JP7467932B2 - Simulation device and simulation program - Google Patents

Description

This disclosure relates to a simulation device and a simulation program that can estimate the behavior of an object placed in a three-dimensional virtual space.

Simulations using computers are applied in a variety of technical fields. As an example of the use of such simulations in FA (Factory Automation), for example, JP 2016-042378 A (Patent Document 1) discloses a simulation of a control program executed in a controller that controls the movement of a machine.

JP 2016-042378 A

In the field of FA, there has been a demand for designing in advance the routing of cables to be attached to industrial robots, which are an example of machinery. Specifically, in the past, when routing cables for industrial robots, the user would actually manipulate the cable to determine the appropriate installation position or cable length, but this work required repeated trial and error and took a long time. Therefore, there has been a demand for designing cable routing (installation position or cable length, etc.) in advance.

The objective of this disclosure is to provide a simulation device and a simulation program that enable the prior design of cable routing to be attached to equipment.

The simulation device according to the present disclosure is a simulation device that calculates the behavior of a cable attached to a device, and includes a cable behavior calculation unit that calculates the behavior of a second object placed in a virtual space corresponding to the device using parameters related to the cable attachment based on the behavior of a first object placed in a virtual space corresponding to the device, and an evaluation unit that evaluates the behavior of the second object calculated by the cable behavior calculation unit based on the behavior.

According to the above disclosure, the behavior of the cable can be calculated based on the behavior of the equipment using parameters related to the cable installation, and by evaluating the calculated behavior, the cable routing can be designed from the evaluated parameters related to the installation.

In addition, the simulation can be performed to design cable routing without the need for an actual device to which the cable will be attached.

In the above disclosure, the behavior of the first object includes behavior calculated for each predetermined time step, and the cable behavior calculation unit calculates the behavior of the second object for each time step using parameters based on the behavior of the first object corresponding to that time step.

According to the above disclosure, it is possible to calculate the behavior of the cable for each time step based on the behavior of the equipment calculated for each time step.

In the above disclosure, the cable behavior calculation unit includes a physical simulator.
According to the above disclosure, the behavior of the cable can be calculated using a physical simulator.

In the above disclosure, the second object includes a modeled rigid body link in which adjacent rigid bodies are connected by joints, and the physical simulator calculates the behavior of the second object by performing calculations based on the behavior of the first object according to equations that represent the relationship between the positions and orientations of adjacent rigid bodies in the modeled rigid body link and the constraints imposed on the relationship between the positions and orientations of the rigid bodies, which are conditions corresponding to the joints.

According to the above disclosure, the cable can be modeled as a rigid link with constraints imposed, and its behavior can be calculated using equations that represent the model.

In the above disclosure, the simulation device further includes a load calculation unit that calculates the load on the second object based on the behavior of the second object calculated by the cable behavior calculation unit.

According to the above disclosure, the load on the second object can be calculated based on the calculated behavior.

In the above disclosure, the load includes the load applied to each rigid body included in the second object.
According to the above disclosure, the load acting on each rigid body can be calculated.

In the above disclosure, the simulation device displays a load based on the behavior of the second object calculated at each time step according to a time series of time steps.

According to the above disclosure, it is possible to display the fluctuations in the load on the second object according to a time series of time steps.

In the above disclosure, the simulation device changes the display mode of a load that exceeds a threshold.

According to the above disclosure, a load that exceeds a threshold can be presented by changing the display mode.

In the above disclosure, the evaluation unit evaluates the behavior of the second object based on the load calculated by the load calculation unit.

According to the above disclosure, the behavior of the second object can be evaluated based on the load.

In the above disclosure, the simulation device includes a parameter setting unit that sets parameters, and when the load satisfies a predetermined condition, outputs the parameters that were set when calculating the behavior of the second target.

According to the above disclosure, parameters can be set (changed) when a simulation is performed, and when the load satisfies a specified condition, the parameters used to calculate the behavior can be output.

In the above disclosure, the parameters include the length of the cable or the location of the cable attachment.

According to the above disclosure, the parameters can include cable length and mounting location.
In the above disclosure, the parameters include a parameter representative of the stiffness of the cable.

In accordance with the above disclosure, the parameters can include the stiffness of the cable to be attached to the device.

In the above disclosure, the device includes a robot, and the behavior of the first object is calculated by emulation of a robot program having command codes for operating the robot.

According to the above disclosure, a simulation of the behavior of a cable attached to a robot can be performed based on a first behavior calculated by an emulator of a robot program.

In the above disclosure, an image generation unit is further provided that generates an image that visualizes the virtual space.

According to the above disclosure, a virtual space with a simulated object arrangement can be visualized and provided to a user.

The simulation program according to the present disclosure is a simulation program that causes a computer to execute a method for calculating the behavior of a cable attached to a device. This method includes a step of calculating the behavior of a second object placed in a virtual space corresponding to the cable based on the behavior of a first object placed in a virtual space corresponding to the device, using parameters related to the cable attachment, and a step of evaluating the calculated behavior of the second object based on the behavior.

According to the above disclosure, by executing the simulation program, the behavior of the cable can be calculated based on the behavior of the device using parameters related to the cable installation, and by evaluating the calculated behavior, the cable layout can be designed from the evaluated parameters related to the installation. In addition, the simulation can be performed without the actual device to which the cable is to be installed, and the cable layout can be designed.

This disclosure allows the routing of cables to be attached to equipment to be designed in advance.

FIG. 1 is a diagram illustrating an example of an application scene of a cable simulation device 1B according to an embodiment of the present invention. 1 is a diagram illustrating a schematic diagram of a device simulated by a simulation device 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a unit configuration of a control system 2 according to the present embodiment. FIG. 1 is a schematic diagram showing an example of a hardware configuration for implementing a simulation device according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing an example of a functional configuration for implementing a simulation device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a processing sequence of the cable simulation device 1B according to the present embodiment. 10 is a diagram illustrating an example of a UI screen for setting parameters of a cable according to the embodiment; FIG. 13 is a diagram illustrating another example of a UI screen for setting parameters of a cable according to the embodiment. FIG. FIG. 13 is a diagram illustrating a data association of the cable simulation according to the present embodiment, using cable data 146. FIG. 2 is a diagram illustrating an example of a physical simulation model of the cable according to the present embodiment. FIG. 11 is a diagram showing an example of simultaneous equations 147 for the physical simulation model of the cable of FIG. 11A and 11B are diagrams illustrating an example of updating a position in a physical simulation according to the present embodiment. 1 is a flowchart illustrating a cable simulation according to the present embodiment and related processing. FIG. 2 is a diagram illustrating an example of load information 142 according to the present embodiment. 4 is a flowchart of an evaluation process according to the present embodiment. FIG. 2 is a diagram showing an example of a display screen of load information 142 according to the embodiment.

Each embodiment will be described below with reference to the drawings. In the following description, the same parts and components are given the same symbols. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

<A. Application Examples＞
An example of a scene in which the present invention is applied will be described. Fig. 1 is a diagram showing a schematic diagram of an example of a scene in which a cable simulation device 1B according to the present embodiment is applied. The device 1B calculates (estimates) the behavior of a cable that can be attached to a robot 30, which is an example of a device provided in an FA production line. Note that the device to which the cable is attached is not limited to the robot 30. The robot 30 includes, but is not limited to, an arm 301 that is configured with multiple joints. The robot 30 includes a robot hand 210 that is detachably attached to the arm 301 at the tip end by a connector 7. The arm 301 includes , cables 341, 342 and 343 are attached using cable guides 350, 351, 352 and 353 on surface 306 (FIG. 10) of arm 301. Cable guide 350 is attached to robot hand 210. Cable 341 is mounted between cable guides 350 and 351 , cable 342 is mounted between cable guides 351 and 352 , and cable 343 is mounted between cable guides 352 and 353 .

Because the cables 341, 342, and 343 have similar characteristics (shape, material, etc.), they are collectively referred to as cable 340 in the common description. The cable 340 is formed, for example, by covering a linear conductor constituting a signal line with an insulator. The material of the insulator can be, but is not limited to, a resin material such as plastic, rubber, or vinyl. The material of the conductor can be, but is not limited to, a metal having electrical conductivity. Because the cable guides 350, 351, 352, and 353 have similar characteristics (shape, material, etc.), they are collectively referred to as cable guide 350 in the common description. By attaching the cable 340 to the robot 30 via the cable guide 350, other devices such as the robot controller 310 can exchange signals with the robot 30 via the cable 340.

Considering that cables 340 for robots are generally expensive and that the work of laying them takes a long time as described above, if the appropriate layout of the cable 340 to be attached to the actual robot 30 is designed in advance and an operator lays the cable 340 based on the design results, the cost of laying the cable 340 (including the cost of the cable 340 and the work time) can be reduced. This advance design is realized by performing a cable simulation using the cable simulation device 1B.

Specifically, the cable simulation device 1B includes a cable simulator 165 that calculates (estimates) the behavior in a three-dimensional virtual space of an object (hereinafter also referred to as a second target) corresponding to the cable 340 attached to the robot 30, and an evaluation module 167 that evaluates the calculated behavior. In FIG. 1, this three-dimensional virtual space is defined, for example, by orthogonal X-, Y-, and Z-axes. The cable simulation device 1B can be implemented in an information processing device 100 that is configured, for example, by a general-purpose computer, and the cable simulator 165 and the evaluation module 167 are realized by the information processing device 100 executing a predetermined program.

The cable simulation calculates the behavior of the second object based on the equipment behavior data 2520. The equipment behavior data 2520 indicates the behavior of an object (hereinafter also referred to as the first object) corresponding to the robot 30, which is placed in the same three-dimensional virtual space as the object of the cable 340. This first object is not limited to, but includes, for example, an object corresponding to the robot 30 and the robot hand 210 attached to the robot 30.

Here, the equipment behavior data 2520 is calculated by the information processing device 100, or provided to the cable simulation device 1B from an external device. The equipment behavior data 2520 is provided to the cable simulation device 1B. The equipment behavior data 2520 is calculated, for example, by executing a simulation that calculates the behavior of the first object in the three-dimensional virtual space for each predetermined time step ti. The behavior of the first object indicated by the equipment behavior data 2520 includes the position of the first object that changes over time in the three-dimensional virtual space.

The cable simulator 165 is an example of a "cable behavior calculation unit." The cable simulator 165 calculates the behavior of a second object placed in the same three-dimensional virtual space in synchronization with the above-mentioned predetermined time step using cable parameters 139 related to the attachment of the cable 340 to the robot 30 based on the behavior of the first object indicated by the equipment behavior data 2520, i.e., the time-series position in the three-dimensional virtual space. The cable parameters 139 are parameters of a type that should be considered in the design of the routing of the cable 340, and include, but are not limited to, the length of the cable 340 and the attachment position of the cable 340 (i.e., the position of the cable guide 350). For example, the cable parameters 139 may include parameters that affect the behavior, such as parameters that depend on the material of the cable 340 (e.g., parameters that represent the hardness of the cable 340).

The cable simulation calculates the behavior of an object (second target) corresponding to cable 340 in a three-dimensional virtual space, which is synchronized with the behavior of an object (first target) corresponding to robot 30. The behavior of the object (second target) corresponding to cable 340 includes the position and orientation of the object on each of the X, Y, and Z axes in the three-dimensional virtual space. This orientation is represented by a combination of roll angle α, pitch angle β, and yaw angle γ, which are acceleration components for the X, Y, and Z axes, for example.

The evaluation module 167 is one example of an "evaluation unit." The evaluation module 167 evaluates the behavior of the second object based on the behavior of the second object calculated by the cable simulator 165. The evaluation module 167 evaluates the behavior based on, for example, a load on the second object calculated from the behavior of the second object, more specifically, a load that affects the behavior. Such a load is calculated by a load calculation module 166 provided in the cable simulation device 1B.

The load calculation module 166 is one example of a "load calculation unit." The load calculation module 166 calculates the load for each time step based on the behavior of the second object. The type of load is not limited, but may include at least one of the following: elongation, bending, and twisting of the second object, the number of collisions of the second object, and the force applied to the second object when a collision occurs. Furthermore, the type of load may include a value indicating whether or not the bending radius exceeds the minimum bending radius (a value specified by the specifications of the cable 340).

When the evaluation module 167 determines that the calculated load satisfies the predetermined conditions, it evaluates the length and attachment position of the cable 340 (i.e., the position of the cable guide 350) indicated by the parameters set in the cable simulation as design values that can realize optimal routing. The cable simulation device 1B outputs, stores, or communicates the evaluation information.

In the cable simulation, the behavior of a second object corresponding to the cable 340 is calculated using attachment parameters based on equipment behavior data 2520 indicating the behavior of a first object corresponding to the robot 30 in a three-dimensional virtual space, and the calculated behavior of the second object is evaluated. The evaluation can indicate whether the design values for the routing of the cable 340 indicated by the parameters applied to the cable simulation are appropriate. Therefore, even if there is no actual device (robot 30, cable 340, and cable guide 350), it is possible to implement an optimal design for the routing of the cable 340.

A more specific application example of this embodiment will now be described.
B. Example of a Control System
FIG. 2 is a diagram showing a schematic diagram of a device simulated by the simulation device 1 according to the present embodiment. The simulation device 1 includes a system simulation device 1A that estimates the behavior of a device, which is an actual device controlled by a PLC (Programmable Logic Controller) 200 of a control system 2 provided in an FA production line. The simulation device 1 can be implemented in an information processing device 100 that is configured with a general-purpose computer including a terminal device such as a PC (Personal Computer) or a tablet terminal, and the information processing device 100 executes a predetermined program to realize a system simulation that estimates the behavior of the device. The information processing device 100 provides a support tool for supporting a user in operating the control system 2. The support tool includes a setting tool for preparing an execution environment of the simulation, an execution environment of a control program for the control system 2, and a communication environment of the control system 2. The support tool is provided to the user by, for example, a UI (User Interface).

In FIG. 2, the information processing device 100 is communicatively connected to the PLC 200, but it is also possible to perform a simulation without being connected to the PLC 200. The cable simulation device 1B described above may be provided in the simulation device 1. In that case, the simulation device 1 provides an environment in which cable simulation and system simulation can be performed.

Referring to FIG. 2, the control system 2 includes a PLC 200, a robot controller 310, and servo motor drivers 531 and 532. The PLC 200, the robot controller 310, and the servo motor drivers 531 and 532 are connected in a daisy chain via a field network 22. For example, EtherCAT (registered trademark) is adopted for the field network 22. However, the field network 22 is not limited to EtherCAT. The information processing device 100 may be connected to the PLC 200 via a network 80. Any wired or wireless communication means may be adopted for the network 80. The PLC 200 and the information processing device 100 communicate with each other according to, for example, USB (Universal Serial Bus).

The PLC 200 executes the designed control program based on field values including sensor output values from the field network 22, and controls the robot 30 and the equipment related to the transport of the conveyor 230 by providing target values to the robot controller 310 or the servo motor drivers 531, 532, respectively, according to the results of the execution.

Servomotor drivers 531 and 532 drive servomotors 41 and 42 of the conveyor 230. Encoders 236 and 238 are arranged on the rotation shafts of the servomotors 41 and 42. The encoders output the servomotor position (rotation angle), rotation speed, cumulative number of rotations, etc. to the PLC 200 as feedback values for the servomotors 41 and 42.

The robot 30 and the conveyor 230 work together to move the workpiece 232. For simplicity, the movement of the workpiece 232 will be described here, but it is not limited to this. For example, the robot 30 may process the workpiece 232 placed on the tray 9.

In FIG. 2, as an example of a drive device for the robot 30, servo motors 1301, 1302, 1033, and 1304 (hereinafter collectively referred to as "robot servo motors") provided on the robot 30 and a robot controller 310 that drives the robot servo motors are shown. Similarly, as an example of a drive device for the conveyor 230, servo motor drivers 531 and 532 that drive servo motors 41 and 42 provided on the conveyor 230 are shown.

The robot controller 310 drives the robot servo motors of the robot 30. An encoder (not shown) is disposed on the rotation axis of each robot servo motor. The encoder outputs the position (rotation angle), rotation speed, cumulative number of rotations, etc. of the servo motor as feedback values for the robot servo motor to the robot controller 310.

The servo motor drivers 531, 532 drive the corresponding servo motors 41, 42 according to the command values. The control system 2 further includes a photoelectric sensor 6 and an openable/closable stopper 8 associated with the conveyor 230. The photoelectric sensor 6 detects that a tray 9 provided on the transport surface of the conveyor 230 has arrived in front of a specified work tracking area, and transmits the detection value to the PLC 200. The stopper 8 closes according to the command value to stop (fix) the tray 9 that has arrived within the tracking area.

The robot hand 210 of the robot 30 is attached according to the process. The types of the robot hand 210 include, but are not limited to, parallel hands, multi-fingered hands, and multi-jointed hands, and may also include types that pick and place the workpiece 232 by suction.

The robot 30 performs pick-and-place in accordance with command values from the robot controller 310. Specifically, the robot 30 picks up the workpiece 232 placed on the tray 9 on the conveyor 230 with the robot hand 210, moves the picked-up workpiece 232 to a predetermined position on the table 55, and places it on the table 55. The opening and closing operation of the robot hand 210 to pick or place the workpiece 232 is controlled in accordance with command values from the robot controller 310.

The equipment whose behavior is estimated by the simulation performed by the system simulation device 1A includes, for example, the conveyor 230 that transports the workpiece 232 and the robot 30 (robot 30 and robot hand 210) that handles the workpiece 232, but the equipment whose behavior is estimated is not limited to these. The cable simulation device 1B calculates (estimates) the behavior of the cable based on the behavior of the equipment calculated (estimated) by the system simulation.

The information processing device 100 may design a control program using the results of such simulations. The control program designed on the information processing device 100 is sent to the PLC 200 via the field network 22.

C. Control and position in 3D virtual space
With reference to FIG. 2, the control of the robot 30 and the conveyor 230, which are the target devices in the system simulation, and the behavior of these devices in the three-dimensional virtual space will be described.

As described above, the robot 30 and the conveyor 230 have movable parts that can be moved by multiple drive axes. Each of these drive axes is driven by a servo motor. Specifically, the robot 30 has multiple arms that are driven by the rotation of the robot servo motors (servo motors 1301 to 1304). Each robot servo motor drives each corresponding arm by rotating. The robot controller 310 controls the driving of the robot servo motors, so that each arm is driven three-dimensionally. The behavior of the robot 30 is realized by driving each arm in this way. Similarly, the conveyor 230 and the tray 9 on the conveying surface move when the servo motors 41 and 42 rotate. The amount of movement (speed, direction, distance, etc. of movement) is determined by the amount of rotation (direction of rotation, angle) of the servo motors 41 and 42. The behavior of the conveyor 230 and the tray 9 and other devices is realized by driving the servo motors 41 and 42 in this way.

In the embodiment, each arm 301 of the robot 30 is associated with a virtual axis, and the position of the robot 30 is determined from the position of each axis. The PLC 200 controls the robot 30 according to a target position converted into a time series for each axis, and the speed and trajectory of the movement of each arm 301 are changed to a speed and trajectory that follows the target.

The target position of the robot 30 is stored in advance, for example, in the PLC 200. The robot controller 310 receives the target position from the PLC 200, determines the amount of rotation of each robot servo motor based on the received target position, and outputs a command value specifying the determined amount of rotation to each robot servo motor.

(c1. Coordinate system of three-dimensional virtual space)
An example of a process for calculating the position of the axis corresponding to each arm 301 of the robot 30 in the three-dimensional virtual space according to the present embodiment will be described. In this embodiment, the coordinate system in the three-dimensional virtual space is exemplified as a world coordinate system shared by each unit such as the robot 30 and the PLC 200. When calculating the position in the world coordinate system, in this embodiment, the rotation amount of the servo motor 1301 is represented as αA, the rotation amount of the servo motor 1302 as αB, the rotation amount of the servo motor 1303 as αC, and the rotation amount of the servo motor 1304 as αD. By performing a calculation using a predetermined function for each of the servo motor rotation amounts (αA, αB, αC, αD), each of the servo motor rotation amounts (αA, αB, αC, αD) can be converted into a position in the three-dimensional virtual space. For example, when the three-dimensional coordinates P (x, y, z) of the axis of each arm 301 that picks the workpiece 232 are calculated, the behavior of the object corresponding to the robot 30 in the three-dimensional virtual space can be shown by the time-series change in the three-dimensional coordinates P (x, y, z) of each arm 301. In this embodiment, the system simulation device 1A calculates the behavior (time-series change in three-dimensional coordinates P (x, y, z)) of a first object placed in a three-dimensional virtual space corresponding to an equipment (more specifically, a robot 30), and outputs equipment behavior data 2520, which is the calculation result.

The system simulation device 1A can also calculate the behavior in the three-dimensional virtual space of the object corresponding to the workpiece 232 and the conveyor 230 that transports the workpiece 232 in the same manner as the robot 30, and output the calculation results as equipment behavior data 2520.

Furthermore, in the control system 2, the devices are time-synchronized with each other. Specifically, the multiple devices connected to the field network 22, namely the PLC 100, the robot controller 310, the servo motor drivers 531 and 532, and the robot hand 210, each have timers 90, 91, 92, 93, and 94 that are time-synchronized with each other, and the devices operate based on these timers, thereby synchronizing the timing of sending and receiving data, including control commands.

<D. Overall configuration of the control system>
Fig. 3 is a schematic diagram showing an example of a unit configuration of the control system 2 according to the present embodiment. Referring to Fig. 3, the control system 2 includes a PLC 200, servo motor drivers 531, 532 and a remote IO terminal 5 connected to the PLC 200 via a field network 22, a robot controller 310 to which a cable 340 is connected, and IO devices provided in the field, such as a photoelectric sensor 6, a proximity sensor 87 provided in a stopper 8, and encoders 236, 238.

The PLC 200 includes an arithmetic unit 13 that performs the main arithmetic processing, one or more IO units 14, and a special unit 17. These units are configured to be able to exchange data with each other via a system bus 81, and are supplied with power from a power supply unit 12. An information processing device 100 can be connected to the arithmetic unit 13.

The IO unit 14 collects detection values 61, 71, 237, and 239 from IO devices including the photoelectric sensor 6, the proximity sensor 87 of the stopper 8, and the encoders 236, 238. The proximity sensor 87 detects without contact that the tray 9 has approached the stopper 8 to a predetermined distance. The detection values from each IO device are set (written) in, for example, a memory provided in the IO unit 14. The calculation unit 13 executes calculations of the control program using the values collected by the IO unit 14, and sets (writes) the values of the calculation results in the memory of the IO unit 14. The peripheral devices or IO devices operate by referring to the values in the memory of the IO unit 14.

The field network 22 may be connected to a robot controller 310, servo motor drivers 531, 532, and a remote IO terminal 5. The IO remote terminal 5 includes a communication coupler 52 for performing processing related to data transmission in the field network 22, and one or more IO units 53. These units are configured to be able to exchange data with each other via a remote IO terminal bus 51.

The servo motor drivers 531 and 532 are connected to the arithmetic unit 13 via the field network 22, and drive the servo motors 41 and 42 according to command values from the arithmetic unit 13. The arithmetic unit 13 generates these command values based on the detection values 237 and 239 from the encoders 236 and 238.

The arithmetic unit 13 executes a predetermined control program by referring to the detection values from the IO devices described above, causing the robot 30 to perform pick-and-place. Specifically, when the arithmetic unit 13 detects that the workpiece 232 has approached a predetermined tracking area from the detection value 61 of the photoelectric sensor 6 and the detection value 71 of the proximity sensor 87, it generates a control command 211 for the robot arm 301 that performs pick-and-place, and a control command 222 for the robot hand 210, and outputs them to the robot 30 via the robot controller 310 and the cable 340.

E. Hardware Configuration
Next, an example of a hardware configuration of the simulation device 1 according to the present embodiment will be described.

Fig. 4 is a schematic diagram showing an example of a hardware configuration for realizing the simulation device 1 according to this embodiment. In this embodiment, the simulation device 1 can be implemented in an information processing device 100 as shown in Fig. 4. Specifically, the simulation device 1 is realized by the processor 102 of the information processing device 100 executing necessary programs. In Fig. 4, the simulation device 1 is provided with an environment for performing a system simulation and a cable simulation.

The information processing device 100 includes, as its main components, a processor 102 that executes an operating system (OS) and various programs as described below, a main memory 104 that provides a working area for storing data necessary for the processor 102 to execute the programs, an operation unit 106 that accepts user operations such as a keyboard and mouse, an output unit 108 that outputs processing results such as a display 109, various indicators, and a printer, a network interface 110 that is connected to various networks including a network 80, an optical drive 112, a local communication interface 116 that communicates with external devices, and a storage 111. These components are connected to enable data communication via an internal bus 118 or the like.

The information processing device 100 reads various programs or data from a computer-readable storage medium 114, which includes an optical storage medium (e.g., a DVD (Digital Versatile Disc)) that non-transiently stores computer-readable programs, using the optical drive 112, and installs the programs or data in the storage 111, etc.

The various programs or data executed by the information processing device 100 may be installed via a computer-readable storage medium 114, or may be installed by downloading them via the network interface 110 from a server device (not shown) on the network.

The storage 111 is composed of, for example, a hard disk drive (HDD) or a flash solid state drive (SSD), and stores the programs executed by the processor 102. Specifically, the storage 111 stores a virtual time generation program 120, a relay program 121, a physical simulation program 122, a PLC simulation program 126, a robot emulation program 130, an integration program 134, and a cable simulation program 137 as simulation programs for realizing the simulation according to this embodiment. The storage 111 further stores an image processing program 136 that generates an image displaying an object arranged in a three-dimensional virtual space, an evaluation program 143, and a parameter setting program 145.

When the cable simulation program 137 is executed, it calculates the behavior of the object corresponding to the cable 340 in the three-dimensional virtual space. The cable simulation program 137 includes a load calculation program 138. When the load calculation program 138 is executed, it calculates the load on the cable 340 based on the behavior calculated by the cable simulation program 137. Note that although the load calculation program 138 is said to be included in the cable simulation program 137, it may be a program that does not depend on the execution timing of the cable simulation program 137, i.e., is independent of the cable simulation program 137.

The evaluation program 143 evaluates the behavior based on the behavior of the object corresponding to the cable 340 calculated by the cable simulation program 137. More specifically, the evaluation program 143 evaluates the behavior based on the load information 142 described below, and outputs evaluation data 144 indicating the evaluation result. The evaluation data 144 can be stored in the storage 111.

The parameter setting program 145 stores the cable parameters 139 in the storage 111 based on, for example, user operations on the information processing device 100.

The virtual time generation program 120 generates virtual time for the simulation. The simulation device 1 executes the simulation at a period based on the virtual time.

The physical simulation program 122 calculates the behavior of an object corresponding to equipment that operates in relation to the movement of the workpiece 232. Equipment for which the behavior of the corresponding object is calculated by the physical simulation program 122 includes, for example, the photoelectric sensor 6, the conveyor 230, the tray 9, the stopper 8, and the robot hand 210 that are related to the transportation or movement of the workpiece 232. The physical simulation program 122 is provided with physical simulation parameters 124 that include parameters for defining the behavior of the object corresponding to such equipment, and parameters for defining the weight or shape of the workpiece 232. The values of the physical simulation parameters 124 may be changed as appropriate by user operation, the integrated program 134, or the like.

CAD (Computer Aided Design) data of the workpiece 232 and the equipment related to the transportation or movement of the workpiece 232 may be used as the physical simulation parameters 124. By using CAD data, the behavior of the actual equipment can be reproduced more accurately using objects.

The PLC simulation program 126 calculates the positions of the equipment and work 232 whose corresponding object behaviors are calculated by the physical simulation program 122. The calculated positions are provided to the physical simulation program 122. The PLC simulation program 126 is provided with PLC parameters 128, which include parameters necessary to calculate the above positions.

The robot emulation program 130 functions as a simulator that reproduces the behavior of the robot 30 using an object. The robot emulation program 130 reproduces the pick-and-place of the workpiece 232 by the robot 30 based on the results (behavior of the object) calculated by the physical simulation program 122. The robot emulation program 130 is provided with robot parameters 132 including parameters necessary to reproduce the behavior of the robot 30 using the corresponding object.

The relay program 121 provides a relay function for the physical simulation program 122 and the robot emulation program 130 to exchange data with each other. The relay program 121 is not limited to this, but the relay function is described, for example, by a script command.

The integration program 134 executes processing for linking the physical simulation program 122, the PLC simulation program 126, the robot emulation program 130, and the relay program 121 with each other. Specifically, the integration program 134 generates and updates virtual space information 105, which describes the state of an object in a three-dimensional virtual space, typically on the main memory 104. The physical simulation program 122, the PLC simulation program 126, and the robot emulation program 130 refer to (read) the virtual space information 105 to execute the processing of each simulation, and reflect necessary information from the execution results in the virtual space information 105. The function provided by the integration program 134 reproduces the behavior and processing of the equipment in the control system 2 that includes an equipment that transports the workpiece 232 and a robot 30 that moves the workpiece 232 by pick-and-place.

The image processing program 136 is provided with 3D (three-dimensional) visualization data 135 for display on the display 109. The 3D visualization data 135 includes behavior data 252 and image data 253. The image data 253 includes equipment image data 2530 for drawing an object corresponding to the equipment being simulated, and cable image data 2531 for drawing an object corresponding to the cable 340. The cable image data 2531 includes image data corresponding to an object of the rigid body 304 (described below).

The behavior data 252 includes equipment behavior data 2520 and cable behavior data 2521, which include three-dimensional coordinates P (x, y, z) that are positions calculated using a predetermined function for the positions of each piece of equipment in the virtual space information 105, and time series data. The cable behavior data 2521 indicates the behavior of an object placed in the three-dimensional virtual space corresponding to the cable 340, calculated by the cable simulator 165 based on the equipment behavior data 2520.

The image processing program 136 uses the equipment image data 2530 and the equipment behavior data 2520 to generate image data for stereoscopically depicting the behavior of each object, namely, the workpiece 232, the equipment and robot 30 related to the transport of the workpiece 232, and the robot hand 210 attached to the robot 30, in a three-dimensional virtual space, and outputs the image data to the display 109. The image processing program 136 also uses the cable image data 2531 and the cable behavior data 2521 to generate image data for stereoscopically depicting the behavior of the object corresponding to the cable 340 in a three-dimensional virtual space, and outputs the image data to the display 109.

As a result, objects are displayed on the display 109 according to the behavior calculated by the simulation, the behavior of the equipment of the control system 2 is reproduced, and the behavior of the cable 340 linked to the behavior of the equipment is also reproduced. Note that the image data 253 may include CAD (Computer-Aided Design) data, etc.

The storage 111 stores cable parameters 139 and load information 142, which are parameters of the cable simulation program 137. The cable parameters 139 include initial values 140 and candidate values 141 of parameters used when starting execution of the cable simulation. The candidate values 141 are parameters used in the cable simulation, and generally indicate values different from the initial values 140. The load information 142 indicates the load calculated by executing the load calculation program 138. The cable parameters 139 are parameters specific to the material of the cable 340, and include parameters 149 indicating the stiffness of the cable 340, such as the parameters Stiffness and Damping, which will be described later.

While FIG. 4 shows an example in which the simulation device 1 is realized by a single information processing device 100, the simulation device 1 may be realized by linking multiple information processing devices. In this case, part of the processing required to realize the simulation device 1 may be executed by the information processing device 100, and the remaining processing may be executed by a server (cloud) on a network, etc.

Figure 4 shows an example in which the processor 102 executes one or more programs to realize the simulation device 1, but some of the processing and functions required to realize the simulation device 1 may be implemented using circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

<F. Functional Configuration>
Next, an example of the functional configuration of the simulation device 1 according to the present embodiment will be described. FIG. 5 is a schematic diagram showing an example of the functional configuration for realizing the simulation device 1 according to the present embodiment. The functions shown in FIG. 5 are typically realized by the processor 102 of the information processing device 100 executing programs (such as a virtual time generation program 120, a relay program 121, a physical simulation program 122, a PLC simulation program 126, a robot emulation program 130, an integration program 134, an image processing program 136, a cable simulation program 137, an evaluation program 143, and a parameter setting program 145). The simulation device 1 includes functions for the system simulation device 1A and the cable simulation device 1B, a period generation module 154 that generates an execution period of the system simulation and the cable simulation, and a 3D visualizer 164 for drawing an object in a three-dimensional virtual space based on the simulation result. The 3D visualizer 164 may include a function realized by the image processing program 136 being executed.

(f1. Configuration of the System Simulation Device)
Referring to Figure 5, the system simulation device 1A includes a virtual space information management module 150, a PLC simulator 152, a work behavior simulator 155, a physical simulator 156, a relay module 158, a robot emulator 160, a work tracking module 162, and a 3D visualizer 164.

The virtual space information management module 150 is realized by executing the integrated program 134 (Figure 4), and manages the virtual space information 105 that specifies the behavior (position, posture, etc.) of each object in the three-dimensional virtual space in which the simulation is performed.

The PLC simulator 152 is realized by executing the PLC simulation program 126 (FIG. 4), and calculates the behavior of objects corresponding to equipment related to the transport of the workpiece 232 according to the physical simulation parameters 124. The information calculated by the PLC simulator 152 is reflected in the virtual space information 105.

The PLC simulator 152 is a program that estimates the behavior of the equipment involved in the transport of the workpiece 232, and corresponds to a simulation program that includes a plurality of instructions included in the PLC program. These multiple instructions may include a group of instructions for controlling the behavior of the equipment involved in the transport that is included in the PLC program. The PLC program is written in, for example, a cyclic execution language (e.g., a programming language written in a ladder language).

Each time these commands of the PLC simulator 152 are executed based on the data of the virtual space information 105, command values for controlling, for example, the servo motors 41 and 42 of the conveyor 230 are generated and stored in the virtual space information 105.

The relay module 158 outputs the measurement results of the workpiece 232 by the measurement process using the image measurement parameters 129 of the workpiece 232 to the robot emulator 160. The robot emulator 160 reproduces the behavior of the robot 30 that transports the workpiece arranged in the virtual space according to the measurement results from the relay module 158. The information on the behavior of the robot 30 calculated by the robot emulator 160 is reflected in the virtual space information 105. The robot emulator 160 is realized by executing the robot emulation program 130. The robot emulator 160 outputs the equipment behavior data 2520 that indicates the behavior of the robot 30 that moves the workpiece 232 arranged in the three-dimensional virtual space. The robot emulator 160 performs a simulation by regarding the arm 301 of the robot 30 and the robot hand 210 attached to the tip of the arm 301 as an integrated rigid body.

Specifically, the robot emulation program 130 includes a set of instructions included in the program of the robot controller 310. The set of instructions includes robot program instructions having command codes for causing the robot 30 to operate the workpiece 232. These commands include instructions for calculating a target trajectory of the robot 30 based on output data from the PLC simulator 152 of the virtual space information 105, and for calculating command values indicating the behavior of each axis based on the calculated trajectory.

In this way, when the robot emulator 160 executes a command, it generates command values for each axis that controls the behavior of the robot 30, and outputs the generated command values to the virtual space information management module 150. The virtual space information management module 150 manages (stores) the command values from the robot emulator as virtual space information 105.

The work behavior simulator 155 calculates the behavior of one or more workpiece 232 objects arranged in a three-dimensional virtual space. Specifically, the work behavior simulator 155 is realized by executing the physical simulation program 122 (FIG. 4), and calculates and updates the behavior of the workpiece 232 arranged in the three-dimensional virtual space according to the information on the behavior of the object corresponding to the transport device of the workpiece 232 by the PLC simulator 152. When calculating the behavior of the workpiece 232, the work behavior simulator 155 calculates the position, posture, moving speed, moving direction, etc. of the workpiece 232. The position and posture of the workpiece 232 are calculated based on work parameters arbitrarily set by the user, etc. The information on the position and posture of the workpiece 232 calculated by the work behavior simulator 155 is reflected in the virtual space information 105. The workpiece parameters can also be included in the physical simulation parameters 124.

The physical simulator 156 is realized by executing the physical simulation program 122 (Figure 4). The physical simulator 156 calculates the behavior (position, posture, moving speed, moving direction, etc.) of an object corresponding to equipment for transporting or moving the workpiece 232 according to the physical simulation parameters 124. The objects simulated by the physical simulator 156 include the photoelectric sensor 6, the stopper 8, the tray 9, the robot hand 210, the conveyor 230, and the workpiece 232.

The physics simulator 156 calculates the behavior of these objects, such as their positions and orientations, in accordance with a predetermined physics calculation. The physics simulator 156 performs the calculation by setting the mass parameter 127 of the object, which is one of the physics simulation parameters 124 used in the physics calculation, to zero.

The significance of setting the mass to zero is as follows. That is, if the mass parameter is not zero, the physics simulator 156 uses physics calculations to calculate the components of the mechanical action on each object, such as the velocity, acceleration, and gravity based on the mass of the object, and the physics simulator 156 calculates (updates) the position of the object in the next time step using the calculated components of the mechanical action. Meanwhile, in this embodiment, the PLC simulator 152 and the robot emulator 160 determine (control) the position of each object. Therefore, in order to zero (invalidate) the update components of the object's position by the physics simulator 156, the mass parameter of each object used in the physics calculations of the physics simulator 156 is set to zero.

For objects whose position (behavior) is calculated using physics calculations with a mass of zero, the speed, acceleration, gravity, etc. are also zero, so even if these objects collide with each other, the physics calculations calculate the mechanical components (components such as the object bouncing back, such as repulsion) as zero (nullified), making it possible to nullify the mechanical effects on the object and detect its position in three-dimensional virtual space.

The physical simulator 156 stores the three-dimensional position coordinates P(x, y, z) of the robot hand 210 calculated by physical calculation as equipment behavior data 2520. The physical simulator 156 is executed for each time step, so that the equipment behavior data 2520 includes the time-series three-dimensional coordinates P(x, y, z) corresponding to the robot hand 210.

The work tracking module 162 is realized by executing the robot emulation program 130. The work tracking module 162 tracks the work 232 picked and placed by the robot 30 in a three-dimensional virtual space based on behavior information of the robot 30 from the robot emulator 160. The position information (work position) of the work 232 tracked by the work tracking module 162 is reflected in the virtual space information 105.

(f2. Configuration of cable simulation device)
5, the cable simulation device 1B includes a cable simulator 165 that is realized by executing the cable simulation program 137, and an evaluation module 167 that is realized by executing the evaluation program 143. The cable simulator 165 has a load calculation module 166. The load calculation module 166 is realized by executing the load calculation program 138. Note that the load calculation module 166 may not be provided in the cable simulator 165, but may be independent from the cable simulator 165.

The cable simulator 165 is executed for each time step, and calculates the behavior of an object placed in the three-dimensional virtual space corresponding to the cable 340 using the cable parameters 139 based on the equipment behavior data 2520 corresponding to that time step, and stores the calculation result as cable behavior data 2521.

The cable simulator 165 calculates the behavior of the object corresponding to the cable 340 for each time step, and the cable behavior data 2521 indicates the time series behavior of the cable 340 in the three-dimensional virtual space.

The 3D visualizer 164 corresponds to an image generation unit that generates an image that visualizes the three-dimensional virtual space. The 3D visualizer 164 calculates the three-dimensional coordinates P (x, y, z) of objects in the three-dimensional virtual space corresponding to the workpiece 232, the equipment related to the transport of the workpiece 232, the robot 30, and the robot hand 210, based on the command values for each time step of the virtual space information 105. Equipment behavior data 2520 including the time-series three-dimensional coordinates P (x, y, z) is calculated.

The 3D visualizer 164 generates image data for visualizing the behavior of the equipment in a three-dimensional virtual space based on the equipment behavior data 2520 and the equipment image data 2530, and also generates image data for visualizing the behavior of the cable in a three-dimensional virtual space based on the cable behavior data 2521 and the cable image data 2531. These image data are output to the display 109. As a result, an image showing the behavior of the equipment calculated by the system simulation and an image showing the behavior of the cable 340 calculated by the cable simulation are displayed on the display 109.

The period generating module 154 is realized by executing the virtual time generating program 120. Based on the output of a timer (not shown) possessed by the processor 102, the period generating module 154 outputs a signal ST synchronized with the output of the timer to each of the other parts. Each part executes a process or program in synchronization with the period (hereinafter referred to as a predetermined time step) at which the signal ST is output from the period generating module 154. As a result, each part in FIG. 5 executes in synchronization with each other at each predetermined time step. The period of the signal ST is not limited, but may be determined based on the communication period of the field network 22 (hereinafter also referred to as the "control period") that follows the time synchronization of the control system 2 in FIG. 3. Note that the period indicated by the time step based on the signal ST may be variable.

By linking the various functions shown in FIG. 5 together, it is possible to reproduce the behavior of the cable 340 in conjunction with the behavior of the device.

In this embodiment, the simulation device 1 in FIG. 5 can start one of the system simulation device 1A and the cable simulation device 1B according to an instruction from a user received, for example, via the operation unit 106. The simulation device 1 can also determine the timing to start the system simulation device 1A or the cable simulation device 1B according to an instruction from a user received, for example, via the operation unit 106. For example, the simulation device 1 starts the system simulation device 1A, and then sets the start timing of the cable simulation device 1B. This makes it possible to provide the equipment behavior data 2520 to the cable simulator when the cable simulation device 1B starts.

In FIG. 5, the information processing device 100 is implemented with both the system simulation device 1A and the cable simulation device 1B, but if the equipment behavior data 2520 is available for the cable simulation device 1B, the information processing device 100 may be implemented with only the cable simulation device 1B.

<G. Cable Simulation>
Fig. 6 is a diagram showing a schematic example of a processing sequence of the cable simulation device 1B according to the present embodiment. In Fig. 6, the processing of the cable simulation performed by the cable simulation device 1B is shown in association with peripheral processing. For the sake of explanation, the device behavior data 2520 used in the following cable simulation indicates the behavior of an object corresponding to the robot 30 (more specifically, the arm 301).

Referring to FIG. 6, the user operates the operation unit 106 to input to the information processing device 100 an instruction to set up a system simulation and an instruction to add a cable simulation (steps S80 and S83). The processor 102, in accordance with the user's instructions, sets, for example, various parameters for the system simulation so that the system simulation can be executed. Also, in accordance with the instruction to add a cable simulation, the processor 102 sets a state in which the cable simulation can be executed. For example, the cable simulator 165 is set so that the equipment behavior data 2520 can be referenced.

The user operates the operation unit 106 to input instructions to the information processing device 100 to execute a system simulation and store the equipment behavior data 2520 (step S85).

The processor 102 starts the system simulation device 1A (step S87), stores (holds) the equipment behavior data 2520, which is the result of the system simulation, in the storage 111 (step S88), and outputs a notification that the storage of the equipment behavior data 2520 has been completed, for example, to the display 109 (step S89).

The user operates the operation unit 106 to input the cable parameters 139 to the information processing device 100 (step S91). The parameter setting program 145 executed by the processor 102 stores the cable parameters 139 received from the operation unit 106 in the storage 111.

The user operates the operation unit 106 to input an instruction to start the execution of the cable simulation to the information processing device 100 (step S93). The processor 102 starts the cable simulator 165 in accordance with the instruction to start the execution of the cable simulation.

When the cable simulator 165 is started, it executes a process (loop process) of repeating a cable simulation for each parameter (for each of the initial value 140 and the candidate value 141) (step S100). The cable simulator 165 executes a simulation based on the equipment behavior data 2520 in synchronization with the time step based on the signal ST, thereby calculating and storing cable behavior data 2521 for each time step (step S100a). In addition, when executing the cable simulation, the load calculation module 166 calculates and stores load information 142 for each time step.

The evaluation module 167 executes the evaluation process (step S130). Specifically, the evaluation module 167 evaluates the behavior based on the cable behavior data 2521, more specifically based on the load information 142 calculated from the cable behavior data 2521, and stores the evaluation result, which is evaluation data 144. The evaluation module 167 outputs information on the evaluation data 144 (step S140). For example, it causes the display 109 to display an image based on the evaluation data 144.

(g1. Parameter setting)
For the parameter setting of the cable 340 described above (step S91), the parameter setting program 145 provides a UI tool. Such a UI tool will be described with reference to Figs. 7 and 8. Fig. 7 is a diagram showing a typical example of a UI screen for setting parameters of a cable according to this embodiment. Fig. 8 is a diagram showing a typical example of a UI screen for setting parameters of a cable according to this embodiment. In the cable simulation according to this embodiment, the cable 340 and the cable guide 350 are treated as being integrated.

Figure 7 is an example of a 3D image displayed on the display 109, and shows the arm 301 of the robot 30 and the state in which the cable 340 is attached by attaching a cable guide 350 to the arm 301. The 3D image in Figure 7 is generated by the processor 102 from CAD data of the equipment image data 2530 and the cable image data 2531. The user can set whether or not to connect the cable 340 between the cable guides by, for example, manipulating the image on the display 109.

The user operates the UI screen in FIG. 8 to set initial values 140 and candidate values 141 as cable parameters 139. For example, a set (0) of parameter initial values 140 can be set, and sets (1) to (5) of candidate values 141 can be set. Each set of parameters includes the length of the cable 340 (Cable Length) and the position of each cable guide 350 (Offset From Guide Cad Data). The parameter setting program 145 converts the position of each cable guide 350 from the position on the 3D screen set by the user in FIG. 7. This determines the distance between each cable guide, and the parameter setting program 145 can then determine the length of the cable 340 between the cable guides.

(g2. Data Relevance)
Fig. 9 is a diagram showing a schematic diagram of data associations in a cable simulation according to this embodiment, using cable data 146. In this embodiment, the attachment positions of four cable guides 350, 351, 352, and 353 are set, for example, as shown in Fig. 1, by the user setting operations of Fig. 7 and Fig. 8. As a result, cables 341, 342, and 343 to be connected between each cable guide are set.

In FIG. 9, cable data 146 is stored corresponding to each of cables 341, 342, and 343 in FIG. 1. Cable data 146 indicates data obtained when a cable simulation is performed for the corresponding cable 340 using the initial value 140 and each of two candidate values 141 of cable parameter 139.

The cable data 146 for cables 341, 342, and 343 are referred to as cable data (1), cable data (2), and cable data (3), respectively. In addition, in explanations common to cable data (1), cable data (2), and cable data (3), they are collectively referred to as cable data 146.

Referring to FIG. 9, the cable data 146 includes cable behavior data 2521, load information 142, and evaluation data 144 associated with the initial values 140 and candidate values 141 of the cable parameters 139, respectively.

Here, two types of candidate values 141 of the cable parameter 139, candidate value (1) and candidate value (2), are shown, but the types of the candidate values 141 are not limited to two. The cable behavior data 2521 includes cable behavior data (0), cable behavior data (1), and cable behavior data (2) associated with the initial value 140, candidate value (1), and candidate value (2), respectively. The cable behavior data (0), cable behavior data (1), and cable behavior data (2) indicate the cable behavior data 2521 calculated for each time step ti (i = 1, 2, ... n) by the cable simulation using the parameters of the initial value 140, candidate value (1), and candidate value (2), respectively. In FIG. 9, the load information 142 includes load information (0), load information (1), and load information (2) calculated from the cable behavior data associated with the cable behavior data (0), cable behavior data (1), and cable behavior data (2), respectively. The evaluation data 144 includes evaluation data (0), evaluation data (1), and evaluation data (2) that are associated with load information (0), load information (1), and load information (2), respectively, and are the results of evaluating behavior from the load information.

(g3. Physical Simulation Model)
FIG. 10 is a diagram illustrating an example of a physical simulation model of the cable according to the present embodiment.

The cable simulator 165 according to this embodiment includes a physical simulator that executes a physical simulation. With reference to FIG. 10, in this physical simulation, an object (second target) corresponding to the cable 340 includes a rigid body link modeled by connecting a plurality of rigid bodies 304 together by connecting adjacent rigid bodies 304 with joints (articulations 305). Specifically, the rigid bodies 304 have a predetermined size and shape, and in the rigid body link, the rigid bodies 304 are connected in a row by the joints 305.

The rigid body 304 is, for example, a cylindrical object that does not deform. In the physical simulation, focusing on the center of the rigid body 304, the rigid body 304 is defined as a mass point having the current position and the previous position of the center. The joint 305 corresponds to a joint such as a spring or a damper, and in the model, the joint 305 corresponds to a constraint condition that restricts the translation and rotation of adjacent rigid bodies 304 in the x, y, and z axial directions. In FIG. 10, both ends of the row of rigid bodies 304 are shown attached to the robot 30 by the object 302 corresponding to the cable guide 350. In this way, in the cable simulation, the rigid body link is modeled with a joint structure that adds a constraint condition to the relationship between adjacent rigid bodies with respect to the position and orientation of the rigid body 304. In FIG. 10, the rigid body link is made up of three rigid bodies 304, but the number of rigid bodies 304 is not limited to three. In other words, the number of rigid bodies 304 is set according to the cable length (Cable length in FIG. 8) specified by the cable parameter 139.

In the cable simulation, the behavior of the model (Figure 10) in the three-dimensional virtual space (cable behavior data 2521) is calculated by calculating a constraint equation including constraint conditions representing the model of Figure 10 using cable parameters 139 based on the given behavior of the object in the three-dimensional virtual space corresponding to the robot 30 (equipment behavior data 2520).

11 is a diagram showing an example of simultaneous equations 147 of the physical simulation model of the cable in FIG. 10. Equation 147 includes equations Ati, Bti, and Cti corresponding to each of the rigid bodies 304 in FIG. 10. Each equation includes variables of the position (coordinates of the x-axis, y-axis, and z-axis) and attitude (tilts α (roll), β (pitch), and γ (yaw) of the x-axis, y-axis, and z-axis), respectively, of the rigid body 304, and the values of these variables are calculated by solving simultaneous equations (equation 147). That is, the cable simulator 165 repeatedly solves the simultaneous equations (equation 147) for each time step ti using parameters 139 based on the equipment behavior data 2520. This allows the values of variables corresponding to the position and attitude of each rigid body 304 to be calculated for each time step ti.

(g4. Position update according to constraints)
Furthermore, in the cable simulation, the position of the rigid body 304 is updated (modified) in accordance with a position-based physical simulation (Position Based Dynamics: PBD). Fig. 12 is a diagram showing a schematic diagram of updating the position of the physical simulation according to the present embodiment. The process of updating the position of the rigid body 304 performed by the cable simulator 165 will be described with reference to Fig. 12.

Specifically, in the cable simulation, the behavior of each rigid body 304 is calculated for each time step. As a result of the simulation, when adjacent rigid bodies 304 collide with each other, one of the colliding rigid bodies 304 may invade (sink) into the other (Figure 12 (A)). The cable simulator 165 detects whether a rigid body 304 invades another rigid body 304 (Figure 12 (A)).

In FIG. 12(A), the cable simulator 165 calculates a predicted position Xpredict (Xpredict=x0+v×Δt, where x0=calculated position, Δt=time of time step, and v=velocity) for each time step using the calculated position x0 of the objects (rigid bodies 304) in the three-dimensional virtual space, and detects whether or not the objects collide with each other based on the relationship between the predicted positions Xpredict. A collision includes, for example, the distance between the position (coordinates) of an object and the position (coordinates) of another object in the three-dimensional virtual space being equal to or less than a threshold value. The threshold value may be a value based on the size (width, height, etc.) of the objects. Note that the method of detecting a collision is not limited to this.

12(A), the cable simulator 165 changes the positions (position: Xpredict) of the colliding rigid bodies 304 so as to resolve the intrusion (FIG. 12(B)). In this case, when the position X0 (position: Xpredict) of a certain rigid body 304 is changed to the position X (corrected position: Xcorrect), the position of the other rigid bodies 304 adjacent to the rigid body 304 may shift due to the change. Then, by repeating such position changes, the behavior of each rigid body 304 in the cable simulation becomes stable. In this embodiment, the above constraint conditions correspond to physical constraint parameters for transitioning the behavior of the object to such a stable state.

When the cable simulator 165 changes the position of the rigid body 304, that is, when it calculates the position X of the rigid body 304 (corrected position: Xcorrect), it changes the velocity v (Figure 12 (C)). Specifically, the cable simulator 165 calculates the corrected velocity Vcorrect using Vcorrect = (X - X0) / Δt, and sets the calculated velocity Vcorrect as the velocity v for the next time step (velocity v in Figure 12 (A)).

The above describes updating the x-coordinate position of the rigid body 304, but the cable simulator 165 can also update the y-coordinate position and z-coordinate position in the same manner as updating the x-coordinate position.

In this way, the behavior of the rigid body link is calculated by performing calculations based on the equipment behavior data 2520 according to equations (Equation 147 and the equation shown in FIG. 12) that represent the relationship in position and orientation between adjacent rigid bodies in the modeled rigid body link and the constraint conditions that correspond to the joints and are imposed on the relationship in position and orientation between the rigid bodies. As a result, at each time step, the behavior of the rigid body link made up of rigid body 304 in a state where rigid body 304 has not intruded (a state where the embedment has been resolved) can be calculated.

(g5. Position update based on stiffness of cable 340)
In the cable simulation according to this embodiment, a parameter 149 representing the stiffness of the cable 340 can be included as a parameter related to a constraint condition for transitioning the behavior of the cable 340 to a stable state. The stiffness parameter 149 includes, for example, a parameter Stiffness and a parameter Damping that are specific to the material of the cable 340. The parameter Stiffness indicates how difficult it is for the rigid body 304 to deform, and is equivalent to, for example, Young's modulus. The parameter Damping indicates the damping characteristic of the rigid body 304 against vibration.

The parameter Damping acts to suppress vibration of the cable 340 in the cable simulation. Specifically, the cable guide 350 attached to the robot 30 is moved (its behavior changes) by the robot emulator 160, so the rigid body 304 accelerates according to the speed of the robot 30, and the cable 340 continues to vibrate accordingly. Therefore, by performing a cable simulation using the parameter Damping, it is possible to suppress vibration of the cable 340 by decelerating the speed of the rigid body 304 when the position of the cable guide 350 moves in accordance with the behavior of the robot 30.

The cable simulator 165 performs the calculations shown in STEP 1, STEP 2, and STEP 3 below to perform position updates based on the stiffness of the cable 340.

[STEP 1] The cable simulator 165 calculates the velocity (var_velocity) from the position (prevPositions[current]) calculated in the previous time step of the rigid body 304 and the position (positions[current]) calculated in the current time step, using the calculations of the following (Equation 1). The cable simulator 165 adds gravity, damping, and a force that tries to maintain the shape to the calculated velocity, using the calculations of (Equations 2) to (Equation 6).

var_velocity = (positions[current] - prevPositions[current]) / prevDeltaTime (Equation 1);
var_geometricError=distance-data.maxDistance (Formula 2); in this (Formula 2), the difference (var_geometricError) between the distance (distance) between two adjacent rigid bodies 304 and a threshold value (data.maxDistance) that is the maximum allowable distance is calculated. If the cable simulator 165 determines that the condition (var_geometricError=0) is satisfied, it detects that the two adjacent rigid bodies 304 do not collide (one penetrates the other), and if it determines that the condition is not satisfied, it detects that the collision (intrusion) has occurred.

positionForce(F)=stiffness×−geometricError (Equation 3);
velocity += positionForce * Time.deltaTime (Equation 4);
velocity += Vector3.down * gravity * Time.deltaTime (Equation 5);
velocity *= damping (Eq. 6);
[STEP 2] The cable simulator 165 updates the positions (positions[current]) at the current time step by calculating (Equation 7) and (Equation 8) based on the velocity calculated in [STEP 1] above.

prevPositions[current] = positions[current] (Equation 7);
positions[current] = positions[current] + velocity * Time.deltaTime (Equation 8);
[STEP 3] When the cable simulator 165 detects that the rigid body 304 has invaded (sunk into) another adjacent rigid body 304, it changes the current position (positions[current]) to a position where the intrusion is resolved (no sinking). This position change is performed in accordance with the position update shown in FIG. 12.

The cable simulator 165 repeats the operations of [STEP 1] to [STEP 3] for each of the x, y, and z coordinate positions of all rigid bodies 304.

As a result, at each time step, the position of each rigid body 304 is a position calculated based on the hardness parameter 149 specific to the material of the cable 340, and is a position where the intrusion (sinking) is eliminated. This allows the cable simulator 165 to start the cable simulation for the next time step using such calculated positions.

<H. Flowchart>
Fig. 13 is a flow chart showing the cable simulation and the associated processing according to the present embodiment. Referring to Fig. 13, the cable simulator 165 obtains parameters (the cable 340 length parameter and the cable 340 attachment position (Offset From Guide Cad Data) parameter) from the cable parameters 139 and sets them in the cable simulation program 137 (step S103). This sets the length of the cable 340 between each cable guide, i.e., the number of rigid bodies 304. At the start of the cable simulation, the parameters of the initial values 140 are set in step S103. For the sake of explanation, the length of the cable 340 between each cable guide is the same.

The cable simulator 165 sets the time step ti to an initial value (i=1) (step S105). After that, the cable simulator 165 updates the time step one step at a time (i.e., i=i+1) (step S121) and performs a cable simulation using the parameters set in step S103 based on the equipment behavior data 2520 until the condition (i=n) is satisfied (YES in step S107) (steps S109 to S115).

Specifically, the cable simulator 165 reads out the behavior data corresponding to the current time step ti from the equipment behavior data 2520 (step S109), and calculates the behavior of the object corresponding to the cable 340 based on the behavior data read out using the cable parameters 139 set in step S103 (step S111). In step S111, the cable simulator 165 performs the calculation using the simultaneous equations shown in equation 147 in FIG. 11, the equation for position update according to the constraint conditions (step S11a) in FIG. 12, and the equation for position update according to the stiffness parameters 149 of the cable 340 (step S11b). For example, the Projected Gauss-Seidel method can be used to calculate the constraint equations using these constraint conditions. The cable behavior data 2521 indicating the behavior of the cable 340 calculated in step S111 is stored in the storage 111.

When the position of the object (the position of each rigid body 304) at the current time step ti is calculated in step S111, the load calculation module 166 calculates the load on the rigid link based on the cable behavior data 2521, which is the cable simulation result for that time step ti (step S113), and outputs the calculated load information 142 (step S115). The load information 142 is stored in the storage 111. Then, the process proceeds to the next time step ti (step S121) and returns to step S107. In step S107, the cable simulator 165 determines whether the condition (ti>tn) is satisfied.

If the condition (ti>tn) is not satisfied (NO in step S107), the process proceeds to step S109. However, if it is determined that the condition is satisfied (YES in step S107), the cable simulator 165 determines whether the next cable parameter 139 is stored in the storage 111, i.e., whether the candidate value 141 is stored (step S123).

If it is determined that the next cable parameter 139 is not stored (NO in step S123), the process ends. However, if it is determined that the next cable parameter 139 is stored (YES in step S123), the process returns to step S103. This causes the next cable parameter 139 (candidate value 141) to be read (step S103), and a cable simulation (steps S105 to S121) is performed using the next cable parameter 139.

According to the process of FIG. 13, the behavior of the cable object (rigid link) is calculated (step S111) in association with each of the cable parameters 139 (initial value 140, candidate value 141), and the cable behavior data 2521, which is the calculation result, and the load information 142 based on the cable behavior data 2521 are stored (FIG. 9).

<I. Load Calculation>
The load calculation module 166 calculates the load information 142 as shown in FIG. 14 based on the cable behavior data 2521. In this embodiment, the type of load 1412 applied to the cable 340 includes, but is not limited to, bending, stretching, twisting, the number of collisions, and repulsive force. FIG. 14 is a diagram showing an example of the load information 142 according to this embodiment. In FIG. 14, load information (0), load information (1), and load information (2) associated with cable behavior data (0), cable behavior data (1), and cable behavior data (2), respectively, are shown. Since the load information (0) to the load information (2) include similar items, they are collectively referred to as the load information 142 in a common description.

Referring to FIG. 14, the load information 142 is the load applied to each rigid body 304 constituting the rigid link between the cable guides for each position 1411 between the cable guides, and includes the load indicated by type 1412. The rigid link between the cable guides is made up of, for example, j rigid bodies 304, and the position 1411 in FIG. 14 is specified by the position of each rigid body 304 (positions indicated by 1, 2, 3, ... j).

The load calculation module 166 calculates the load acting on each rigid body 304, i.e., each position 1411, according to a predetermined calculation based on the behavior (position and posture) of each rigid body 304. For example, the twist and bend of each rigid body 304 is calculated from the behavior of the rigid body 304 and adjacent rigid bodies 304, the extension is calculated from the distance between adjacent rigid bodies 304 (the greater the distance, the greater the pulling force), and the repulsive force is calculated from the penetration distance at the time of the collision described above (the greater the distance, the greater the repulsive force). Note that the collision calculated by the load calculation module 166 may include a collision with an object other than the rigid body 304 (such as the robot 30, the workpiece 232, or the conveyor 230).

J. Evaluation Process
Based on each of the load information 142 (load information (0), load information (1), and load information (2)), the evaluation module 167 evaluates the behavior (cable behavior data 2521) of the rigid link associated with the load information 142. The evaluation module 167 stores the evaluation results, that is, evaluation data 144 (evaluation data (0), evaluation data (1), and evaluation data (2)), in association with the cable behavior data 2521 ( FIG. 9 ).

FIG. 15 is a flowchart of the evaluation process according to this embodiment. The evaluation module 167 sets conditions for evaluating the cable behavior data 2521 in the evaluation program 143 based on user operations from the operation unit 106 (step S131). The predetermined conditions for evaluation are indicated, for example, using a threshold value of the load magnitude for each load type 1412. More specifically, the predetermined conditions may specify the cable parameters 139 used in calculating the cable behavior data 2521 for which the corresponding load value is the smallest, as the optimal values for designing the cable routing.

The evaluation module 167 searches for load information 142 associated with each cable parameter 139 based on the specified evaluation conditions (step S133). Based on the search results, the evaluation module 167 determines whether or not load information 142 that satisfies the specified conditions can be found from the load information 142 associated with each cable parameter 139 (step S135). Specifically, it determines whether or not load information 142 can be found in which the values of all load types 1412 are less than the threshold value.

When the evaluation module 167 determines that the load information 142 satisfying the predetermined condition has not been found (NO in step S135), it outputs that the cable behavior data 2521 that matches the predetermined condition has not been calculated, i.e., the cable parameters 139 have not been set (step S139). When the evaluation module 167 determines that the load information 142 satisfying the predetermined condition has been found (YES in step S135), the cable behavior data 2521 that matches the predetermined condition has been calculated, so it searches for and outputs the cable parameters 139 used in the calculation (set in step S103 at the time of the calculation), i.e., the cable parameters 139 associated with the load information 142 (step S137).

The user can design in advance the routing of the cable 340 from the output cable parameters 139 (parameters for cable length (Cable Length) and installation position (Offset From Guide Cad Data)) to provide the optimal cable length and installation position that satisfies the specified evaluation conditions. In addition, by following the pre-design of the routing, the time required for the task of routing the cable 340 can be shortened, and it is also possible to design the routing jig, such as the cable guide 350, in advance.

<K. Display example＞
16 is a diagram showing an example of a display screen of the load information 142 according to the present embodiment. The load calculation module 166 or the evaluation module 167 displays an image based on the load information 142 on the display 109. For example, a graph of bending load information 142 is shown in FIG. 1. The horizontal axis of the graph represents position information, which is an identifier (segment number) of each rigid body 304, and the vertical axis represents bending values. In addition, in FIG. 16, the graphs for each time step are displayed in the depth direction of the screen according to the time step chronology. For example, the load applied to each position of the object at each time step can be displayed in 3D. The magnitude of the bending and the variation of the magnitude of the load at that location over time can be shown on one screen.

From the screen of FIG. 16, the user can visually check the parts of the cable 340 object that are subject to heavy loads or the load that is applied to the entire object, and can also predict the lifespan of the cable 340 corresponding to the object from the load information 142. For example, in order to identify the parts that are subject to heavy loads, the evaluation module 167 changes the display mode (display color, etc.) for loads that exceed a threshold value among the loads corresponding to the identifiers of each rigid body 304. FIG. 16 shows an example of a bending information screen, but other types of load information 142 can also be displayed in a similar manner.

The 3D visualizer 164 may also generate image data that visualizes the three-dimensional virtual space using the equipment behavior data 2520 and cable behavior data 2521, which are the results of the simulation. The display 109 displays an image based on this image data. This allows the display 109 to display a three-dimensional image in which the cable 340 attached to the robot 30 moves in conjunction with the movement of the robot 30.

<L. Program>
The cable simulation is exemplified by a configuration provided by the processor 102 of the information processing device 100 in FIG. 4 executing a program stored in a memory such as the storage 111, but some or all of the provided configuration may be implemented using a dedicated hardware circuit (for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array)). Alternatively, the main part of the information processing device 100 may be realized using hardware that conforms to a general-purpose architecture. In this case, virtualization technology may be used to run multiple OSs with different uses in parallel, and necessary applications may be run on each OS.

In addition, the information processing device 100 may include multiple processors. In this case, the cable simulation can be performed by the multiple processors. In addition, if the processor 102 includes multiple cores, the cable simulation can be performed by the multiple cores in the processor 102.

The storage medium 114 of the information processing device 100 is a medium that stores information such as a program by electrical, magnetic, optical, mechanical, or chemical action so that a computer or other device, machine, etc. can read the recorded information such as the program. The processor 102 of the information processing device 100 may acquire the program or equipment behavior data 2520 related to the cable simulation described above from these storage media.

<M. Note>
The present embodiment as described above includes the following technical idea.
[Configuration 1]
A simulation device (1B) for calculating a behavior of a cable (340) attached to a device (30), comprising:
a cable behavior calculation unit (165) that calculates behaviors (304, 305) of a second object that is placed in the virtual space and corresponds to the cable, based on a behavior (2520) of a first object that is placed in the virtual space and corresponds to the device, using parameters (139) related to the installation of the cable;
and an evaluation unit (167) that evaluates the behavior of the second object calculated by the cable behavior calculation unit based on the behavior.
[Configuration 2]
The behavior of the first target includes a behavior calculated for each predetermined time step (ti),
The cable behavior calculation unit
2. The simulation apparatus according to configuration 1, further comprising: a calculation unit for calculating, for each time step, a behavior of the second object based on a behavior of the first object corresponding to the time step, using the parameters.
[Configuration 3]
3. The simulation apparatus according to configuration 2, wherein the cable behavior calculation unit includes a physical simulator.
[Configuration 4]
The second object includes a rigid body link modeled as a series of adjacent rigid bodies (304) connected by joints (304);
The physical simulator includes:
the simulation device according to configuration 3, wherein the behavior of the second object is calculated by performing, based on the behavior of the first object, an operation according to an equation expressing a relationship in positions and orientations between adjacent rigid bodies in the modeled rigid link and a constraint condition corresponding to the joint and imposed on the relationship in positions and orientations between the rigid bodies.
[Configuration 5]
5. The simulation apparatus according to configuration 4, further comprising: a load calculation unit (166) that calculates a load on the second target based on the behavior of the second target calculated by the cable behavior calculation unit.
[Configuration 6]
6. The simulation apparatus of claim 5, wherein the load includes a load acting on each of the rigid bodies of the second object.
[Configuration 7]
The simulation device according to configuration 5 or 6, further comprising: a display unit that displays the load based on the behavior of the second object calculated at each time step in accordance with a time series of the time steps.
[Configuration 8]
8. The simulation device according to configuration 7, further comprising: a display mode of a load exceeding a threshold value being changed.
[Configuration 9]
The evaluation unit is
The simulation device according to any one of configurations 5 to 8, further comprising: a load calculation unit that calculates a behavior of the second target based on the load calculated by the load calculation unit.
[Configuration 10]
A parameter setting unit (145) for setting the parameters,
8. The simulation device according to any one of configurations 5 to 7, further comprising: a parameter set at the time of calculating the behavior of the second target, the parameter being output when the load satisfies a predetermined condition.
[Configuration 11]
9. The simulation apparatus of any one of configurations 1 to 8, wherein the parameters include a length of the cable or an attachment position of the cable (140, 141).
[Configuration 12]
12. The simulation apparatus of any one of configurations 1 to 11, wherein the parameters include a parameter (149) representing a stiffness of the cable.
[Configuration 13]
The apparatus includes a robot (30);
13. The simulation device according to any one of configurations 1 to 12, wherein the behavior of the first object is calculated by emulation of a robot program having a command code for operating the robot.
[Configuration 14]
14. The simulation device according to any one of configurations 1 to 13, further comprising an image generation unit (164) that generates an image that visualizes the virtual space.
[Configuration 15]
A simulation program (138) for causing a computer (100) to execute a method for calculating a behavior of a cable (340) attached to a device (30), comprising:
The method comprises:
A step (S100) of calculating a behavior of a second object, which is placed in the virtual space and corresponds to the cable, based on a behavior of a first object, which is placed in the virtual space and corresponds to the device, using a parameter related to the installation of the cable;
and evaluating the calculated behavior of the second object based on the behavior (S130).

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and is intended to include all modifications within the meaning and scope of the claims.

1 Simulation device, 1A System simulation device, 1B Cable simulation device, 30 Robot, 100 Information processing device, 102 Processor, 104 Main memory, 105 Virtual space information, 106 Operation unit, 108 Output unit, 109 Display, 111 Storage, 112 Optical drive, 114 Storage medium, 120 Virtual time generation program, 121 Relay program, 122 Physical simulation program, 124 Physical simulation parameters, 126 Simulation program, 130 Robot emulation program, 132 Robot parameters, 134 Integration program, 135 Visualization data, 136 Image processing program, 137 Cable simulation program, 138 Load calculation program, 139 Cable parameters, 140 Initial value, 141 Candidate value, 142 Load information, 143 Evaluation program, 144 Evaluation data, 145 Parameter setting program, 146 Cable data, 147 Equation, 149 Hardness parameters, 150 Virtual space information management module, 154 Period generation module, 155 Work behavior simulator, 156 Physical simulator, 160 Robot emulator, 164 3D visualizer, 165 Cable simulator, 166 Load calculation module, 167 Evaluation module, 210 Robot hand, 252 Behavior data, 253 Image data, 301 Arm, 304 Rigid body, 305 Joint, 340, 341, 342, 343 Cable, 350, 351, 352 Cable guide, 2520 Equipment behavior data, 2521 Cable behavior data, 2530 Equipment image data, 2531 Cable image.

Claims (14)

A simulation device that calculates behavior of a cable attached to a device whose operation is controlled according to commands communicated via a network, comprising:
a cable behavior calculation unit that calculates a behavior of a second object that is placed in the virtual space and corresponds to the cable, based on a behavior of a first object that is placed in the virtual space and corresponds to the device, by using a parameter related to installation of the cable;
an evaluation unit that evaluates the behavior of the second object calculated by the cable behavior calculation unit based on the behavior ,
The behavior of the first target includes a behavior calculated for each time step indicating a period based on a communication period of the network,
The cable behavior calculation unit
A simulation device that calculates, for each time step, a behavior of the second object based on the behavior of the first object corresponding to that time step, using the parameters . The simulation device according to claim 1 , wherein the cable behavior calculation unit includes a physical simulator. The second object includes a rigid body link modeled by connecting adjacent rigid bodies with joints;
The physical simulator includes:
3. The simulation device according to claim 2, wherein the behavior of the second object is calculated by performing, based on the behavior of the first object, an operation according to an equation that represents a relationship in positions and orientations between adjacent rigid bodies in the modeled rigid link and a constraint condition that corresponds to the joint and is imposed on the relationship in positions and orientations between the rigid bodies. The simulation device according to claim 3 , further comprising a load calculation unit that calculates a load acting on the second target based on the behavior of the second target calculated by the cable behavior calculation unit. The simulation apparatus according to claim 4 , wherein the load includes a load applied to each of the rigid bodies included in the second target. The simulation device according to claim 4 , further comprising : a display unit configured to display the load based on the behavior of the second target calculated at each time step in accordance with a time series of the time steps. The simulation device according to claim 6 , wherein a display manner of a load exceeding a threshold value is changed. The evaluation unit is
The simulation device according to claim 4 , further comprising: a load calculation unit that calculates a behavior of the second target based on the load calculated by the load calculation unit. A parameter setting unit that sets the parameters,
The simulation device according to claim 4 , further comprising: a parameter set at the time of calculating the behavior of the second target, the parameter being output when the load satisfies a predetermined condition. The simulation device according to claim 1 , wherein the parameters include a length of the cable or an attachment position of the cable. The simulation device according to claim 1 , wherein the parameters include a parameter representing a stiffness of the cable. The device includes a robot;
The simulation device according to claim 1 , wherein the behavior of the first target is calculated by emulation of a robot program having a command code for operating the robot. The simulation device according to claim 1 , further comprising an image generation unit that generates an image that visualizes the virtual space. A simulation program for causing a computer to execute a method for calculating behavior of a cable attached to a device whose operation is controlled according to commands communicated via a network, the method comprising:
The method comprises:
calculating a behavior of a second object, which is placed in a virtual space corresponding to the cable, based on a behavior of a first object, which is placed in the virtual space corresponding to the device, by using a parameter related to the installation of the cable;
and evaluating the calculated behavior of the second object based on the behavior ,
The behavior of the first target includes a behavior calculated for each time step indicating a period based on a communication period of the network,
In the step of calculating the behavior of the second target,
a behavior of the second object is calculated for each time step using the parameters based on the behavior of the first object corresponding to that time step .

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