JP7763962B2 - Tracking control device and tracking control method - Google Patents

Description

This disclosure relates to a tracking control device and a tracking control method for controlling mechanical systems such as robots and automatic assembly machines that perform work on objects moving on a transport means such as a conveyor.

In the conveying system, the robot works on the object while it is being transported without stopping on the conveyor, eliminating the need for intermittent conveyor operation and the need for the robot to temporarily place the object while working. This reduces system costs and shortens overall work time by reducing the number of work processes.

The tracking control device described in Patent Document 1 calculates a predicted picking position where a robot is expected to pick an object being transported, based on sensing information of the workpiece and the transport speed of the transport device. This tracking control device generates a motion trajectory of the robot from the operation start position to the predicted picking position based on the robot's posture at the operation start position and its posture at the predicted picking position. The robot is then controlled according to the motion trajectory, and after the robot reaches the predicted picking position, it synchronizes the robot's motion with the transport speed of the transport device, and then picks up the object being transported by the transport device.

Japanese Patent Application Laid-Open No. 2019-25618

However, with the technology of Patent Document 1, the speed of the transport device and the robot is synchronized after the robot hand reaches the object to be transported, which means that it takes time before the robot can start work such as picking, which results in a long time before the robot can start work.

The present disclosure has been made in consideration of the above and aims to provide a tracking control device that can shorten the time it takes for a robot to start working.

To solve the above-mentioned problems and achieve the objectives, the tracking control device of the present disclosure includes a synchronization command generation unit that generates a synchronization command that synchronizes the operation of a mechanical system that performs work on a transported object with the operation of a transport device that transports the transported object, based on a synchronization start timing, which is the timing at which synchronization starts that is determined based on the transport speed of the transported object.The tracking control device of the present disclosure also includes an operation command generation unit that generates a mechanical system operation command, which is a command for the mechanical system to reach a target position, and a combination unit that combines the synchronization command and the mechanical system operation command to generate a combined command and outputs the generated combined command.The synchronization command generation unit generates a synchronization command that starts synchronization before the mechanical system reaches the target position.

The tracking control device disclosed herein has the effect of shortening the time it takes for a robot to start working.

FIG. 1 is a diagram showing a configuration of a tracking control device according to a first embodiment; FIG. 10 is a diagram for explaining an example of a velocity waveform of a synchronization command generated by the tracking control device according to the first embodiment; FIG. 1 is a diagram illustrating a configuration of a synchronization start timing determination unit included in a tracking control device according to a first embodiment; 1 is a flowchart showing a processing procedure of a process executed by a tracking control device according to a first embodiment; FIG. 10 is a diagram illustrating a configuration of a synchronization start timing determination unit included in a tracking control device according to a third embodiment. FIG. 10 is a diagram showing a configuration of a tracking control device according to a fourth embodiment; FIG. 10 is a diagram for explaining a point where a tracking control device according to a fourth embodiment calculates torque. FIG. 13 is a diagram showing a configuration of a tracking control device according to a fifth embodiment. FIG. 13 is a diagram for explaining an interference consideration-free region used when the tracking control device according to the fifth embodiment determines the synchronization start timing. FIG. 20 is a diagram showing a configuration of a learning unit included in a tracking control device according to a sixth embodiment; FIG. 20 is a diagram showing a configuration of a learning unit included in a tracking control device according to a seventh embodiment; FIG. 10 is a diagram showing a configuration example of a processing circuit provided in the tracking control device according to the first to seventh embodiments when the processing circuit is realized by a processor and a memory. FIG. 10 is a diagram showing an example of a processing circuit when the processing circuit included in the tracking control device according to the first to seventh embodiments is realized by dedicated hardware.

Below, the tracking control device and tracking control method relating to embodiments of the present disclosure are described in detail with reference to the drawings.

Embodiment 1.
1 is a diagram showing the configuration of a tracking control device according to embodiment 1. The transport system of embodiment 1 includes a tracking control device 50A, a robot 6, and a transport device such as a conveyor (not shown).

The tracking control device (mechanical system control device) 50A is a computer that controls mechanical systems such as robots and automatic assembly machines that perform work on objects moving on transport means such as conveyors. In embodiment 1, we will explain the case where the tracking control device 50A controls the robot 6. The tracking control device 50A is connected to the robot 6.

Robot 6 is a robot that performs work on transported objects, such as workpieces, transported by a conveyor. An example of robot 6 is a robot that picks up transported objects. Robot 6 may also be a robot that places a picked workpiece on a transported object transported by a conveyor, or a robot that performs work such as tightening screws.

The tracking control device 50A of embodiment 1 starts synchronizing the movement speed of the robot 6 with the conveying speed of a conveying device such as a conveyor before the robot 6 reaches the object to be conveyed. The process of synchronizing the movement speed of the robot 6 with the conveying speed is a process in which the relative speed between the conveying speed and the movement speed of the robot 6 is controlled to zero. The tracking control device 50A controls the movement speed of the robot 6 by sending a command including a synchronization command to the robot 6, thereby controlling the movement speed of the robot 6 to be the same as the conveying speed. Hereinafter, the control of the robot 6 that synchronizes the movement speed of the robot 6 with the conveying speed will be referred to as synchronization control.

The tracking control device 50A comprises a synchronization start timing determination unit 1, a synchronization command generation unit 2, a target position determination unit 3, an operation command generation unit 4, each axis control unit 5, a gripping operation control unit 7, and a synthesis unit 15.

The target position determination unit 3 receives the conveyance speed of the conveyor and the conveyance position of the object to be conveyed from an external device. The target position determination unit 3 receives the conveyance speed and conveyance position from, for example, a conveyance control device that controls a conveyance device such as a conveyor. The target position determination unit 3 may also receive the conveyance speed and conveyance position from a sensor, camera, etc.

The target position determination unit 3 determines the target position (robot target position) of the robot 6 based on the transport speed and transport position. The target position is the target position of the operation command generated by the operation command generation unit 4, and is the reference position when the robot 6 performs work on the transported object. The robot 6 operates in accordance with the synchronization command generated by the synchronization command generation unit 2 and the robot operation command generated by the operation command generation unit 4, which is an operation command that does not take into account synchronization with the robot 6. The target position determination unit 3 sends the target position to the operation command generation unit 4 and the synchronization start timing determination unit 1.

The motion command generator 4, which is a robot motion command generator, generates a robot motion command (mechanical system motion command) that is a motion command for the robot 6 to move up to the target position of the robot 6 based on the target position. The robot motion command includes a position command for the target position, etc. The motion command generator 4 sends the generated robot motion command to the synthesis unit 15.

The operation command generation unit 4 also generates a gripping operation command that commands the robot 6 to perform a gripping operation at a target position based on a gripping program for executing the gripping operation, etc. The gripping operation command is a command to operate the robot hand, which is the hand of the robot 6. The operations specified in the gripping operation command include, for example, an operation to lower the robot hand to the position of the transport object, an operation to open and close the robot hand, and an operation to return the robot hand to its original position. The operation command generation unit 4 sends the gripping operation command to the gripping operation control unit 7. Note that the operation command generation unit 4 may also generate a work command that commands a work other than a gripping operation and send it to the gripping operation control unit 7.

The synchronization start timing determination unit 1 receives the conveyor transport speed and the transport position of the transported object from an external device, and receives the target position from the target position determination unit 3. The synchronization start timing determination unit 1 determines the timing to start synchronization control using a synchronization command (hereinafter sometimes referred to as synchronization start timing) based on the transport speed, transport position, and target position. The synchronization start timing is the timing before the robot 6 reaches the target position specified in the robot operation command. In other words, the synchronization start timing is the timing for starting synchronization control before the robot 6 reaches the target position specified in the robot operation command. The synchronization start timing determination unit 1 sends a synchronization start command indicating the determined synchronization start timing to the synchronization command generation unit 2.

When the synchronization command generation unit 2 receives a synchronization start command from the synchronization start timing determination unit 1, it generates a synchronization command for synchronizing with the conveyor transport speed based on the synchronization start command. The synchronization command generation unit 2 generates a synchronization command for starting synchronization control before the robot 6 reaches the target position specified in the robot operation command. In other words, the synchronization command generation unit 2 starts generating a synchronization command before the robot operation command generated by the operation command generation unit 4 reaches the target position.

For example, if a conveyor that moves an object to be transported in a linear direction is used as the transport device, the synchronization command generation unit 2 generates a synchronization command (motion command) that causes the robot hand of the robot 6 to move parallel to the conveyor, with the target position of the robot motion command generated by the motion command generation unit 4 as the starting point and the conveyor's transport speed as the target speed. This synchronization command includes a command to accelerate until the target speed is reached, a command to operate at the target speed, and a command to decelerate from the target speed until stopping. The synchronization command generation unit 2 sends the generated synchronization command to the synthesis unit 15.

The synthesis unit 15 synthesizes the synchronization command and the robot operation command for each axis to generate a synthesized command, and outputs the generated synthesized command to each axis control unit 5.

The axis control units 5 are control units that control the movement of the robot 6. The axis control units 5 control each axis of the robot 6 based on the combined command (an operation command that combines a synchronization command and a robot operation command) sent from the combination unit 15. The grip operation control unit 7 controls the robot hand in accordance with the grip operation command sent from the operation command generation unit 4.

Here, we will explain an example of the velocity waveform in a Cartesian coordinate system of the synchronization command generated by the synchronization command generation unit 2. Figure 2 is a diagram for explaining an example of the velocity waveform of the synchronization command generated by the tracking control device of embodiment 1. The horizontal axis of the graph shown in Figure 2 represents time, and the vertical axis represents the velocity command of the synchronization command. The positive side of the vertical axis corresponds to the operating direction of the conveyor (the transport direction of the transported object). Note that Figure 2 omits the illustration of the velocity command during deceleration.

The speed command (speed waveform) of the synchronization command generated by the synchronization command generation unit 2 is a command to accelerate from 0 to the conveyor transport speed V at a constant acceleration, and after reaching the conveyor transport speed V, to operate parallel to the conveyor while maintaining the conveyor transport speed V. This speed command accelerates from 0 to the conveyor transport speed V at a constant acceleration during the acceleration time Kt.

The distance traveled by the robot hand during the acceleration time Kt under the synchronization command is the acceleration distance L. In other words, the distance traveled while the robot hand is accelerating up to the conveying speed V under the synchronization command is the acceleration distance L. In Figure 2, the acceleration distance L, which is the distance traveled under the synchronization command during the acceleration time Kt, is indicated by the shaded area.

As shown in Figure 2, if the acceleration during acceleration is constant and the velocity waveform during acceleration is shown as a straight line, then L = (V x Kt) / 2. The distance traveled by the robot hand during the deceleration time is the deceleration distance. If the acceleration and deceleration are constant and the velocity waveform during acceleration and deceleration is shown as a straight line, the velocity waveform of the synchronization command will be a trapezoidal velocity command.

Figure 3 is a diagram showing the configuration of the synchronization start timing determination unit provided in the tracking control device of embodiment 1. The synchronization start timing determination unit 1 has a synchronization start position calculation unit 10 and a synchronization start position arrival determination unit 11.

The synchronization start position calculation unit 10 receives the target position, which is the target position of the robot 6, from the target position determination unit 3, and receives the conveyor transport speed from an external device such as a sensor.

The synchronization start position calculation unit 10 determines the position of the transported object on the conveyor at which synchronization control begins (hereinafter sometimes referred to as the synchronization start position) based on the target position and transport speed. In other words, the synchronization start position calculation unit 10 determines the position of the transported object on the conveyor at which the synchronization command generation unit 2 begins generating a synchronization command. In embodiment 1, the synchronization start position is referred to as the synchronization start position PS.

For example, if the target position determined by the target position determination unit 3 is the target position P, the synchronization start position calculation unit 10 determines the position of the transported object on the conveyor at which generation of the synchronization command begins, as the point located upstream of the conveyor from the target position P by the acceleration distance L in the synchronization command (synchronization start position PS). In other words, the synchronization start position calculation unit 10 determines the point at which the transported object reaches a position a predetermined specific distance (acceleration distance L) ahead of the target position P as the synchronization start position PS.

If the direction of movement (transport direction) of the object being transported by the conveyor is the positive X-axis direction, the axis perpendicular to the X-axis in the horizontal plane is the Y-axis, and the XY coordinates of the target position P of the robot 6 are (Px, Py), the synchronization start position PS at which the synchronization command is initiated is PS = (Px - L, Py). In other words, synchronization control begins when the object being transported on the conveyor reaches PS = (Px - L, Py). The synchronization start position calculation unit 10 sends the synchronization start position PS to the synchronization start position arrival determination unit 11.

The synchronization start position arrival determination unit 11 receives the synchronization start position PS from the synchronization start position calculation unit 10 and receives the moment-by-moment transport position of the transported object from an external device such as a transport control device. The moment-by-moment transport position received by the synchronization start position arrival determination unit 11 from the external device is an estimate of the position of the transported object (position estimate value Xh). The position estimate value Xh, which is the transport position, is estimated based on the position of the transported object on the conveyor calculated from an image captured when the transported object passes under an imaging unit (camera, etc.) installed upstream of the conveyor, the elapsed time since the image capture, and the post-image capture output from an encoder, which is a measuring device installed on the conveyor.

The synchronization start position arrival determination unit 11 compares Px-L with Xh, and outputs a synchronization start command to the synchronization command generation unit 2 when Xh≧Px-L. The synchronization start position arrival determination unit 11 outputs a synchronization start command to the synchronization command generation unit 2, for example, when Xh=Px-L. In other words, the synchronization start position arrival determination unit 11 sets the time when the transported object reaches a position a predetermined specific distance (acceleration distance L) ahead of the target position P as the synchronization start timing, which is the timing to start synchronization, and outputs a synchronization start command to the synchronization command generation unit 2.

In addition, the synchronization start position arrival determination unit 11 is not limited to estimating the position estimation value Xh using the estimation method described above, and may also estimate the position estimation value Xh using a speed command to the conveyor or a design value for the conveyor speed instead of the encoder output.

In addition, in a conveying system, an encoder may not be installed on the conveyor, and the object to be conveyed may be imaged multiple times at intervals by an imaging unit installed upstream of the conveyor. In this case, the synchronization start position arrival determination unit 11 estimates the estimated position value Xh of the object to be conveyed based on, for example, the conveyor speed estimated from the multiple imaging results and the elapsed time since the imaging.

The synchronization command generator 2 generates a synchronization command that has a speed pattern as shown in Fig. 2, with the starting point specified by the motion command generator 4 in the robot motion command as the target position P. In this case, the increment in the position command after the acceleration time Kt from the start of generation of the synchronization command is L, so in the synchronization command generated by the synchronization command generator 2, the amount of movement of the robot 6 from Px in the conveyor motion direction is L, and the speed command in the conveyor motion direction is V. In other words, the speed of the robot 6 reaches V when it has moved L from Px in the conveyance direction.

The X-direction position of the object to be transported on the conveyor is Px - L + (V x Kt). Here, V x Kt is 2L, so the X-direction position of the object to be transported on the conveyor is Px + L, just like the robot 6, and the X-direction velocity of the object to be transported is V. As a result, after the acceleration time Kt or more has elapsed since the start of generation of the synchronization command and the robot operation command has reached the target position P, the position and velocity of the robot 6 and the position and velocity of the object to be transported will match. Therefore, the tracking control device 50A can synchronize the robot 6 and the object to be transported once the robot operation command generated by the operation command generation unit 4 has reached the target position P.

The target position determination unit 3 desirably selects the target position P used by the operation command generation unit 4 so that the acceleration time Kt has elapsed since the start of generation of the synchronization command before the position of the robot 6 corresponding to the robot operation command reaches the target position P. In other words, the target position determination unit 3 sets the start timing of the synchronization command to a time before the position of the robot 6 corresponding to the robot operation command reaches the target position P, and selects the target position P so that the acceleration time Kt has elapsed since the start of the synchronization command and the robot hand position is above the transport object when the robot operation command generated by the operation command generation unit 4 reaches the target position P. In this way, the target position determination unit 3 can ensure that the robot 6 is above the transport object when the robot operation command generated by the operation command generation unit 4 reaches the target position P, and that the transport speed of the robot 6 is synchronized with that of the transport object.

In embodiment 1, the synchronization command generation unit 2 first generates a synchronization command (position command for the robot hand) in a Cartesian coordinate system, and then converts (called inverse transformation) the generated position command for the robot hand into a position command for each axis of the robot 6. This inversely transformed position command is the synchronization command. The position command for each axis generated by the synchronization command generation unit 2 through inverse transformation is added to the robot operation command generated by the operation command generation unit 4.

In the first embodiment, the tracking control device 50A performs an inverse transformation on the synchronization command before adding it to the robot operation command, but the inverse transformation may be performed later. That is, the tracking control device 50A may add the robot operation command in the Cartesian coordinate system generated by the operation command generation unit 4 and the synchronization command in the Cartesian coordinate system in the Cartesian coordinate system, and then perform an inverse transformation.

In embodiment 1, the target position determination unit 3 calculates in advance the robot's operation times ta1 to tak to multiple points P1 to Pk (k is a natural number) on the conveyor in order to determine the target position P of the robot operation command. Of points P1 to Pk, point P1 is the most upstream position, and point Pk is the most downstream position.

The target position determination unit 3 compares the calculated values ta1-tak with the travel times tb1-tbk of the object to be transported on the conveyor from P1 to Pk. Through this comparison, the target position determination unit 3 determines the maximum value n that satisfies tan≧tbn+Kt (n is a natural number from 1 to k), and outputs the point Pn (not shown) corresponding to this value n as the target position P to the motion command generation unit 4. The maximum value n corresponds to the point where the synchronization command starts the slowest among the points where the speed in the synchronization command reaches the speed of the transport device before the robot motion command generated by the motion command generation unit 4 reaches the target position P. In other words, the maximum value n corresponds to the point Pn where the section where the combined motion matches the robot motion command generated by the motion command generation unit 4 is the longest among the points where the speed in the synchronization command reaches the speed of the transport device before the robot motion command generated by the motion command generation unit 4 reaches the target position P.

In addition, the target position determination unit 3 in embodiment 1 adopts the point corresponding to the operating time that satisfies the maximum n as the target position P, but it may also output a point Pm (not shown) where m < n (m is a natural number) as the target position P.

The target position determination unit 3 is not limited to determining the target position P by calculating the travel time to multiple points on the conveyor in advance, but may also determine the target position P by other methods. For example, the target position determination unit 3 may calculate the robot 6's operation time ta to a predetermined specific point P0 (not shown) on the conveyor and the travel time tb of the object to be transported on the conveyor to that specific point P0, and then determine the target position P based on the comparison of ta and tb. For example, when the x-coordinate of P0 is P0x, the target position determination unit 3 calculates Px by Px = P0x + (ta - tb - Kt - α) × V, and determines the calculated Px as the target position P. Here, α is a predetermined constant. Rather than performing any calculation, the target position determination unit 3 may store a predetermined point PA (not shown) and output PA to the motion command generation unit 4 as the target position P. In this case, the PA may be a point set based on any information such as the conveying speed of the conveyor or the moving speed of the robot 6.

The gripping operation control unit 7 starts the gripping operation at the later of time tr1 when the position command generated by the operation command generation unit 4 reaches the target position P, or time tr2 after the acceleration time Kt has elapsed since the start of generation of the synchronization command. In other words, if the acceleration time Kt has not elapsed since the start of generation of the synchronization command even when the position command has reached the target position P, the gripping operation control unit 7 waits until the acceleration time Kt has elapsed before starting the gripping operation. Also, if the acceleration time Kt has elapsed since the start of generation of the synchronization command even when the position command has not reached the target position P, the gripping operation control unit 7 waits until the position command has reached the target position P before starting the gripping operation.

The grasping operation is an operation in which the robot's hand is lowered and the hand is opened and closed. When any of the following conditions is met: at the end of the grasping operation, at the end of the hand's raising operation after the end of the grasping operation, after a specified time has elapsed since the end of the grasping operation, or after a specified time has elapsed since the start of the grasping operation, the grasping operation control unit 7 sends a command to end the generation of a synchronization command to the synchronization command generation unit 2. When the synchronization command generation unit 2 receives the command to end the generation of a synchronization command, it slows down the speed command of the synchronization command to 0 and stops the synchronization command.

In embodiment 1, the gripping operation control unit 7 starts the gripping operation when the later of times tr1 and tr2 is reached, but the gripping operation may also start when a predetermined time tc has elapsed after the later of times tr1 and tr2, taking into account the control system.

In addition, the tracking control device 50A in embodiment 1 generates a synchronization command so that the hand of the robot 6 is synchronized exactly with the speed of the object being transported, but it is not necessary to be limited to achieving strict synchronization, and it is also possible to match the speed to a slightly different speed within the allowable error range when performing a grasping operation. Note that matching the speed to a slightly different speed within the allowable error range is also defined as "synchronization."

In addition, while embodiment 1 has been described using an example in which an object to be transported is transported linearly on a conveyor, the tracking control device 50A can also be applied to systems in which the object is transported in an arc. When an object to be transported is transported linearly on a conveyor, the tracking control device 50A considers the acceleration distance L and deceleration distance as linear distances, but in a system in which the object is transported in an arc, the acceleration distance L and deceleration distance can be treated as distances on the circumference and similar calculations can be performed.

In this way, the tracking control device 50A of the first embodiment starts synchronizing the position and speed of the transport object and the robot 6 before the robot operation command reaches the target position P. Then, the tracking control device 50A realizes synchronization of the speeds of the transport object and the robot 6 by positioning the tip of the robot 6 above the transport object when the robot operation command reaches the target position P and by making the speeds of the transport object and the robot 6 the same. As a result, the tracking control device 50A can achieve both suppression of gripping position errors and shortening of operation time even when performing tracking control.

Next, the processing steps performed by the tracking control device 50A will be explained. Figure 4 is a flowchart showing the processing steps performed by the tracking control device according to the first embodiment.

The target position determination unit 3 of the tracking control device 50A determines the target position P, which will be the starting point when the robot 6 performs work on the transported object, based on the transport position and transport speed of the transported object (step S10).

The synchronization start timing determination unit 1 determines the synchronization start timing for starting synchronization control based on the target position P, the transport position, and the transport speed (step S20). The synchronization command generation unit 2 generates a synchronization command for synchronizing with the conveyor transport speed based on the synchronization start command indicating the synchronization start timing (step S30). This synchronization command is a command for starting synchronization before the position of the robot 6, which is moving in accordance with the robot operation command, reaches the target position P.

The operation command generation unit 4 generates a robot operation command, which is an operation command for the robot 6 to move to the target position P, based on the target position P (step S40). Note that the processing of step S40 and the processing of steps S20 and S30 may be executed first, or the other may be executed first.

The synthesis unit 15 synthesizes the synchronization command and the robot operation command for each axis. The synchronization command is a command to start synchronization before the position of the robot 6 corresponding to the robot operation command reaches the target position P. Therefore, the command synthesized by the synthesis unit 15 is a command to start synchronization before the robot 6 reaches the target position P. In other words, by synthesizing the synchronization command and the robot operation command, the synthesis unit 15 starts synchronization before the robot 6 reaches the target position P (step S50). The individual axis control units 5 control each axis of the robot 6 based on the operation command synthesized from the synchronization command and the robot operation command. In this way, the tracking control device 50A starts synchronization before the robot 6 reaches the target position P. The gripping operation control unit 7 controls the robot hand in accordance with the gripping operation command sent from the operation command generation unit 4.

As described above, the tracking control device 50A generates synchronization commands that align the position and speed of the robot 6 with both the position and speed of the object being transported on the conveyor, thereby reducing errors in the grasping operation by the robot 6 and shortening the operating time of the robot 6.

As such, according to embodiment 1, the tracking control device 50A generates a synchronization command to initiate synchronization before the operation command generated by the operation command generation unit 4 reaches the target position P, and therefore initiates synchronization. Therefore, the positions and velocities of the robot 6 and the object to be transported match when the operation command generated by the operation command generation unit 4 reaches the target position P. This allows the tracking control device 50A to cause the robot 6 to start work when the operation command generated by the operation command generation unit 4 reaches the target position P, thereby shortening the time until the robot 6 starts work.

Embodiment 2.
Next, a second embodiment will be described with reference to Fig. 1. In the second embodiment, a tracking control device 50A generates a rectangular wave velocity command as the velocity waveform of the synchronization command.

The tracking control device 50A of embodiment 2 differs from the tracking control device 50A of embodiment 1 in the method of generating a speed command in the synchronization command generation unit 2. Therefore, in embodiment 2, the method of generating a speed command in the synchronization command generation unit 2 will be described, and other descriptions will be omitted.

The synchronization command generation unit 2 provided in the tracking control device 50A of embodiment 1 generated a synchronization command for accelerating and decelerating at a constant acceleration, but the synchronization command generation unit 2 provided in the tracking control device 50A of embodiment 2 internally generates a rectangular wave speed command. That is, while in embodiment 1 the synchronization command generation unit 2 generated a trapezoidal pattern speed command, in embodiment 2 the synchronization command generation unit 2 generates a speed command that increases the speed in a step-like manner during acceleration and decreases the speed in a step-like manner during deceleration.

The synchronization command generation unit 2 in embodiment 2 generates a square wave speed command, passes the generated speed command through a moving average filter with a window length Kt, which is the same length as the acceleration time Kt, and outputs the result as a speed command to the synthesis unit 15. In other words, the synchronization command generation unit 2 generates a speed command for the robot 6 specified by the synchronization command using the square wave speed command and a moving average filter.

In this way, in embodiment 2, the synchronization command generation unit 2 generates a speed command using a rectangular wave speed command and a moving average filter, making it possible to easily generate a synchronization command even if the conveyor speed fluctuates.

Embodiment 3.
Next, a third embodiment will be described with reference to Fig. 5. A tracking control device 50A according to the third embodiment calculates a synchronization start position using parameters (control system parameters) of feedback control or feedforward control in the control system of each axis of the robot 6.

In embodiment 3, the processing in the synchronization start timing determination unit differs from embodiment 1. Therefore, in embodiment 3, the configuration of the synchronization start timing determination unit and the method for calculating the synchronization start position are explained, and other explanations are omitted.

Figure 5 is a diagram showing the configuration of a synchronization start timing determination unit provided in a tracking control device according to embodiment 3. Of the components in Figure 5, those that achieve the same function as the synchronization start timing determination unit 1 of embodiment 1 shown in Figure 3 are given the same reference numerals, and duplicated explanations will be omitted.

The synchronization start timing determination unit 1A of embodiment 3 has a synchronization start position calculation unit 10A and a synchronization start position arrival determination unit 11.

The synchronization start position calculation unit 10A receives the target position P, which is the target position of the robot 6, from the target position determination unit 3, and receives the conveyor transport speed from an external device such as a sensor. The synchronization start position calculation unit 10A also receives control system parameters from an external device.

As such, embodiment 3 differs from embodiment 1 in that the synchronization start position calculation unit 10A of the synchronization start timing determination unit 1A accepts control system parameters in addition to the target position P and conveying speed.

The synchronization start position calculation unit 10A determines the position on the conveyor of the transported object at which synchronization control begins (synchronization start position PS) based on the target position P, transport speed, and control system parameters. The control system parameters are feedback control or feedforward control parameters in the control system of each axis of the robot 6.

Since delays occur in the control system for each axis of the robot 6, not just in tracking control, the robot 6's hand operates with a delay from the command value to the control system. For example, when the tracking control device 50A moves the robot 6's hand along a straight line or an arc, the robot 6's hand operates along the target trajectory with a delay corresponding to the feedback control or feedforward control parameters and the command value speed. Therefore, in embodiment 3, the synchronization start position calculation unit 10A stores in advance the relationship between the control system parameters and conveying speed and the delay amount Ld of the robot 6 in the direction along a straight line or arc (for example, a correspondence relationship shown in tabular form).

Instead of storing the correspondence between the control system parameters, conveying speed, and delay amount Ld in a table format or the like, the synchronization start position calculation unit 10A may store a function that indicates the relationship between the control system parameters, conveying speed, and delay amount Ld. The function that indicates the relationship between the control system parameters, conveying speed, and delay amount Ld may be derived in advance by the synchronization start position calculation unit 10A, or may be derived in advance by another device and stored in the synchronization start position calculation unit 10A.

The synchronization start position calculation unit 10A derives the delay amount Ld corresponding to the input control system parameters and conveying speed based on the correspondence relationship (table or function) between the control system parameters and conveying speed and the delay amount Ld, and the input control system parameters and conveying speed.

Furthermore, the synchronization start position calculation unit 10A uses the derived delay amount Ld to calculate the synchronization start position PS on the conveyor of the transported object at which generation of the synchronization command begins, using PS = (Px - L - Ld, Py), and transmits the synchronization start position PS to the synchronization start position arrival determination unit 11 as the synchronization start position.

The synchronization start position arrival determination unit 11 receives the synchronization start position PS from the synchronization start position calculation unit 10A. The synchronization start position arrival determination unit 11 also receives the transport position (position estimate value Xh) from time to time. The transport position is an estimated position based on the position of the transport object on the conveyor calculated from an image captured when the transport object passes under an imaging unit installed upstream of the conveyor, the elapsed time since the image was captured, and the output from an encoder, a measuring device installed on the conveyor, after the image was captured.

The synchronization start position arrival determination unit 11 compares Px-L-Ld with Xh, and outputs a synchronization start command to the synchronization command generation unit 2 when Xh≧Px-L-Ld.

In this way, in embodiment 3, the tracking control device 50A calculates the synchronization start position using control system parameters. That is, the synchronization start timing determination unit 1A determines the synchronization start timing taking into account delays in the control system. Therefore, the tracking control device 50A can suppress the effects of delays in the control system and achieve high-precision tracking control that reduces gripping errors of the robot 6 due to delays in the control system.

Embodiment 4.
Next, a fourth embodiment will be described with reference to Fig. 6. The tracking control device of the fourth embodiment calculates the shortest acceleration and deceleration times within a range that does not exceed the maximum and minimum values of the allowable torque acting on each axis of the robot 6, and generates a robot operation command using the calculated acceleration and deceleration parameters.

Figure 6 is a diagram showing the configuration of a tracking control device according to the fourth embodiment. Of the components in Figure 6, those that achieve the same functions as the tracking control device 50A of the first embodiment shown in Figure 1 are given the same reference numerals, and duplicate explanations will be omitted. The conveying system of the fourth embodiment includes a tracking control device 50B, a robot 6, and a conveying device such as a conveyor (not shown).

In addition to the components of the tracking control device 50A, the tracking control device 50B includes a synchronization-considered acceleration/deceleration determination unit 8. The target position determination unit 3 of the tracking control device 50B sends the target position P to the operation command generation unit 4, the synchronization start timing determination unit 1, and the synchronization-considered acceleration/deceleration determination unit 8.

The synchronization-considered acceleration/deceleration determination unit 8 receives the target position P from the target position determination unit 3. The synchronization-considered acceleration/deceleration determination unit 8 also stores in advance the parameters of the synchronization command (speed pattern) to be combined with the robot operation command, i.e., the parameters related to the speed and acceleration/deceleration of the constant speed section of the synchronization command.

The synchronization-considering acceleration/deceleration determination unit 8 determines acceleration/deceleration parameters within a range that satisfies the constraints on each axis of the robot 6, based on the target position P and the synchronization command that is combined with the robot operation command. The acceleration/deceleration parameters are parameters used for accelerating and decelerating the robot operation command generated by the operation command generation unit 4. The acceleration/deceleration parameters are, for example, the acceleration time and deceleration time when the robot 6 performs synchronization processing in accordance with the synchronization command. The acceleration time and deceleration time determined by the synchronization-considering acceleration/deceleration determination unit 8 are the shortest acceleration time and deceleration time within a range that satisfies the allowable value (allowable torque) of the torque acting on each axis of the robot 6, which is determined taking into account the effects of synchronous operation.

The synchronization-considered acceleration/deceleration determination unit 8 sends the determined acceleration/deceleration parameters to the operation command generation unit 4. The operation command generation unit 4 generates a robot operation command using the acceleration/deceleration parameters determined by the synchronization-considered acceleration/deceleration determination unit 8.

Figure 7 is a diagram for explaining the points at which the tracking control device of embodiment 4 calculates torque. The synchronization-considered acceleration/deceleration determination unit 8 predetermines the length (distance SL) of the section on the conveyor 32 where synchronous operation may be performed.

Next, the synchronization-considered acceleration/deceleration determiner 8 calculates the torque acting on each axis of the robot 6 when the robot 6 is operated along the traveling direction of the conveyor 32 from the target position P determined by the target position determiner 3 at the speed pattern of the synchronization command (for example, the synchronization command shown in FIG. 2 ) generated by the synchronization command generator 2. Specifically, the synchronization-considered acceleration/deceleration determiner 8 calculates the torque τa of each axis at the start of the operation (speed 0 at the target position P), the torque τb of each axis at the end of the acceleration (speed V in the moving direction of the conveyor 32 at point TP0 moved by L in the X-axis direction from the target position P), and the torques τc1 to τcK (K is a natural number) at each predetermined point from the start of the constant velocity section until point TP1 separated by a distance SL from the target position P in the X-axis direction is reached.

For example, if the number of predetermined points between point TP0 and the next point TP1 is four as shown in Figure 7, the synchronization-considered acceleration/deceleration determination unit 8 calculates the torques τc1 to τc4 at these four points. If the robot 6 is a six-axis robot, the torques τa, τb, and τc1 to τc4 will all be vectors with six elements.

Next, the synchronization consideration acceleration/deceleration determiner 8 calculates the maximum value τsi _max and minimum value τsi _min of each axis component of torque τa, τb, and τc1 to τc4. Here, i is the number of axes, and if the robot 6 is a six-axis robot, i is a natural number between 1 and 6. For example, the maximum value of the first axis is τs1 _max , and the minimum value of the third axis is τs3 _min . Furthermore, if the calculated τsi _max is τsi _max < 0, the synchronization consideration acceleration/deceleration determiner 8 sets τsi _max = 0. Furthermore, if τsi _min > 0, the synchronization consideration acceleration/deceleration determiner 8 sets τsi _min = 0.

If the effect of synchronization is not taken into consideration, the motion command generation unit 4 calculates the acceleration time Kt0 and deceleration time gt0 that are the shortest within the range that does not exceed the maximum allowable torque τi _max in the positive direction of each axis and the maximum allowable torque −τi _max in the negative direction of each axis, and generates a robot motion command using the acceleration time Kt0 and the deceleration time gt0.

In the fourth embodiment, which takes into account the influence of synchronization, the synchronization-considered acceleration/deceleration determiner 8 calculates the acceleration/deceleration time after correcting the maximum allowable value of each axis to a value that takes into account the influence of synchronization. Specifically, the synchronization-considered acceleration/deceleration determiner 8 calculates the maximum allowable torque τzi _max in the + direction taking into account the influence of synchronization of each axis as τzi _max = τi _max - τsi _max , and calculates the maximum allowable torque τzi _min in the - direction as τzi _min = -τi _max - τsi _min .

The synchronization consideration acceleration/deceleration determination unit 8 calculates the acceleration time Kt1 and deceleration time gt1 that are the shortest within a range in which the torque of each axis does not exceed τzi _max and τzi _min . That is, the synchronization consideration acceleration/deceleration determination unit 8 determines the acceleration time Kt1 that does not exceed τzi _max based on τzi _max , and determines the deceleration time gt1 that does not exceed τzi _min based on τzi _min . The synchronization consideration acceleration/deceleration determination unit 8 transmits the acceleration time Kt1 and the deceleration time gt1 to the motion command generation unit 4 as acceleration/deceleration parameters.

The operation command generation unit 4 receives the acceleration time Kt1 and deceleration time gt1. The operation command generation unit 4 generates a robot operation command using the received acceleration time Kt1 and deceleration time gt1.

Although the fourth embodiment has been described with reference to an example in which the synchronization-considering acceleration/deceleration determiner 8 determines the acceleration time Kt1 based on τzi _max and the deceleration time gt1 based on τzi _min , the synchronization-considering acceleration/deceleration determiner 8 may determine the acceleration time Kt1 and the deceleration time gt1 by other methods. For example, the synchronization-considering acceleration/deceleration determiner 8 may calculate the acceleration time Kt1 within a range not exceeding τi _max and −τi _max , and may calculate the deceleration time gt1 within a range not exceeding τzi _max and τzi _min .

In this way, the synchronization-considered acceleration/deceleration determination unit 8 calculates the acceleration time Kt1 and deceleration time gt1 that are the shortest possible within the range that does not exceed the maximum and minimum values of the allowable torque.The maximum and minimum values of the allowable torque are set to values that take into account the effects of synchronization, as described above.

The synchronization-considering acceleration/deceleration determination unit 8 calculates the acceleration/deceleration time as a command before adding the synchronization command. Any method may be used to calculate the acceleration/deceleration time. The synchronization-considering acceleration/deceleration determination unit 8 may calculate the acceleration time Kt1 and deceleration time gt1 using any method as long as the method takes into account the dynamic characteristics of the robot 6 and calculates the shortest acceleration time Kt1 and deceleration time gt1 without exceeding the allowable torque.

In this way, the tracking control device 50B of embodiment 4 calculates the shortest acceleration and deceleration times that do not exceed the maximum and minimum values of the allowable torque, and generates a robot operation command using the calculated acceleration and deceleration parameters. This allows the tracking control device 50B to shorten the operation time by operating at high speed while satisfying the allowable torque limits, even when operating the robot 6 by adding a synchronization command to the robot operation command.

Embodiment 5.
Next, a fifth embodiment will be described with reference to Figures 8 and 9. The tracking control device of the fifth embodiment starts issuing a synchronization command when the robot hand reaches an area where it does not interfere with the object and the object to be conveyed reaches the synchronization start position.

Figure 8 is a diagram showing the configuration of a tracking control device according to the fifth embodiment. Of the components in Figure 8, those that achieve the same functions as the tracking control device 50A of the first embodiment shown in Figure 1 are given the same reference numerals, and duplicate explanations will be omitted. The conveying system of the fifth embodiment includes a tracking control device 50C, a robot 6, and a conveying device such as a conveyor 32 (not shown in Figure 8).

In addition to the components of the tracking control device 50A, the tracking control device 50C also includes an interference effect determination unit 9. The interference effect determination unit 9 receives robot operation commands from the operation command generation unit 4 from time to time.

The interference effect determination unit 9 determines whether or not the robot end effector has reached the interference consideration-free area A1 based on an area (an interference consideration-free area A1, described later) in which there is no possibility of interference between the robot 6 and an object even if a synchronization command is added to the robot operation command, and the robot operation command. The interference effect determination unit 9 sends information indicating whether or not the robot end effector has reached the interference consideration-free area A1 to the synchronization start timing determination unit 1.

The synchronization start timing determination unit 1 provided in the tracking control device 50C of embodiment 5 outputs a synchronization start command to the synchronization command generation unit 2 when the robot hand reaches the interference-free area A1 and the object to be transported reaches the synchronization start position.

Compared to the tracking control device 50A, the tracking control device 50C is different in that it includes an interference effect determination unit 9 and in the processing performed by the synchronization start timing determination unit 1, synchronization command generation unit 2, and gripping operation control unit 7. The following mainly describes the differences between the processing performed by the tracking control device 50C and the processing performed by the tracking control device 50A.

Figure 9 is a diagram for explaining the interference-free area used by the tracking control device of embodiment 5 when determining the synchronization start timing. In Figure 9, the transported object on which the robot 6 performs work is illustrated as transported object 31.

The interference-free area A1 is an area where there is no risk of interference occurring between the robot 6 and an object (such as an obstacle (not shown), such as equipment or a sensor between the robot 6 and the conveyor 32) even if a synchronization command is added to the robot operation command. The interference-free area A1 includes the area through which the transported object 31 passes.

The interference effect determination unit 9 pre-stores an interference-free area A1 as shown in Figure 9. The interference effect determination unit 9 receives robot operation commands generated from time to time by the operation command generation unit 4. The interference effect determination unit 9 determines whether the position of the robot hand corresponding to the robot operation command has reached the interference-free area A1.

The interference effect determination unit 9 outputs information (e.g., "0") indicating that the position of the robot hand has not yet reached the interference-free area A1 to the synchronization start timing determination unit 1. After the position of the robot hand has reached the interference-free area A1, the interference effect determination unit 9 outputs information (e.g., "1") indicating that the position has reached the interference-free area A1 to the synchronization start timing determination unit 1.

The synchronization start position arrival determination unit 11 of the synchronization start timing determination unit 1 determines whether the transported object 31 has reached the synchronization start position, as in embodiment 1. In embodiment 5, the synchronization start timing determination unit 1 does not output a synchronization start command to the synchronization command generation unit 2 if the output from the interference effect determination unit 9 is "0" even when the transported object 31 has reached the synchronization start position, i.e., if it has received information indicating that the object has not yet reached the synchronization start position.

When the transported object 31 reaches the synchronization start position and the output from the interference effect judgment unit 9 is "1", the synchronization start timing determination unit 1 outputs a synchronization start command to the synchronization command generation unit 2. If the output from the interference effect judgment unit 9 is already "1" when the transported object 31 reaches the synchronization start position, the synchronization start timing determination unit 1 immediately outputs a synchronization start command to the synchronization command generation unit 2. In other words, when the output from the interference effect judgment unit 9 is "1", the synchronization start timing determination unit 1 outputs a synchronization start command to the synchronization command generation unit 2 at the time the transported object 31 reaches the synchronization start position.

In this way, the synchronization start timing determination unit 1 outputs a synchronization start command to the synchronization command generation unit 2 when the position of the robot hand reaches the interference-free area A1 and the object to be transported 31 reaches the synchronization start position.

The synchronization command generation unit 2 may delay the output of the synchronization start command from the desired timing due to interference considerations. In this case, if the tracking control device 50C uses the synchronization command generated by the synchronization command generation unit 2 as is, the position of the robot hand will be shifted by the amount of the delay in starting synchronization. Therefore, the synchronization command generation unit 2 outputs a synchronization command that corrects the shifted position. For example, if the delay from the desired timing of the synchronization start command output by the synchronization start timing determination unit 1 is Kd, the delayed timing causes the transported object 31 to move to a position advanced by Lc = Kd x V. Therefore, the synchronization command generation unit 2 generates a command (hereinafter referred to as a correction command) to move from (Px, Py) as the starting point to (Px + Lc, Py) with an acceleration time Kt. The synchronization command generation unit 2 superimposes the correction command to move to (Px + Lc, Py) with an acceleration time Kt on the original synchronization command without any timing delay, and sends the result to the synthesis unit 15 as the corrected synchronization command.

If the synchronization command generation unit 2 expects that the maximum or minimum allowable torque will be exceeded if the result of superimposing the above-mentioned correction command is output as a synchronization command, it calculates the arrival time Kt2 required to reach the position (Px + Lc, Py) without exceeding the maximum or minimum allowable torque. In this case, the synchronization command generation unit 2 superimposes a correction command for moving to (Px + Lc, Py) in the arrival time Kt2 onto the original synchronization command with no timing delay, and sends the result to the synthesis unit 15 as a synchronization command.

The gripping operation control unit 7 starts the gripping operation at the later of time tr1 when the position command generated by the operation command generation unit 4 reaches the target position P, and time tr2 after the acceleration time Kt has elapsed since the start of generation of the synchronization command.

In addition, if the arrival time Kt2 to (Px + Lc, Py) is longer than the acceleration time Kt, the gripping operation control unit 7 starts the gripping operation at the later of the time tr1 when the position command generated by the operation command generation unit 4 reaches the target position P, and the time tr3 after the arrival time Kt2 has elapsed since the start of generation of the synchronization command.

In this way, in the tracking control device 50C of embodiment 5, the synchronization start timing determiner 1 determines the timing of starting a synchronization command by taking into account the output from the interference effect determiner 9. That is, the synchronization start timing determiner 1 of the tracking control device 50C outputs a synchronization start command to the synchronization command generator 2 when the position of the robot hand reaches the interference consideration-free area A1 and the transported object 31 reaches the synchronization start position. This enables the tracking control device 50C to prevent interference, synchronize the positions and speeds of the robot 6 and the transported object 31, and shorten the operating time of the robot 6.

Embodiment 6.
Next, a sixth embodiment will be described with reference to Fig. 10. A tracking control device 50A of the sixth embodiment learns the correspondence between the target position P, the transport speed, and the control system parameters and the delay amount Ld, and when controlling the robot 6, infers the delay amount Ld based on the target position P, the transport speed, and the control system parameters.

In the tracking control device 50A of embodiment 6, the synchronization start timing determination unit 1A has a learning unit. The tracking control device 50A of embodiment 6 differs from the tracking control device 50A of embodiment 3 in the processing executed by the synchronization start timing determination unit 1A. Compared to the synchronization start timing determination unit 1A of embodiment 3, the synchronization start timing determination unit 1A of embodiment 6 differs in the method of deriving the delay amount Ld from the input target position P, conveying speed, and control system parameters. The following mainly describes the method of deriving the delay amount Ld.

Figure 10 is a diagram showing the configuration of a learning unit provided in a tracking control device according to embodiment 6. The learning unit (learning device) 21 provided in the tracking control device 50A is arranged, for example, within the synchronization start timing determination unit 1A. The learning unit (learning device) 21 performs both learning and inference.

The first learning unit, learning unit 21, is equipped with a neural network and pre-learns the correspondence (first correspondence) between the combination of target position P, conveying speed, and control system parameters and the delay amount Ld. During learning, learning unit 21 uses the target position P, conveying speed, and control system parameters as inputs to the neural network, and the delay amount Ld corresponding to the target position P, conveying speed, and control system parameters at the time of input as the output (teacher signal) of the neural network to perform learning of the neural network.

The trained neural network is stored in the synchronization start position calculation unit 10A. When the tracking control device 50A actually operates the robot 6, the learning unit 21 outputs from the neural network the delay amount Ld corresponding to the target position P, conveying speed, and control system parameters input to the neural network. The synchronization start position calculation unit 10A uses the delay amount Ld output from the neural network to calculate the synchronization start position PS on the conveyor 32 of the transported object at which generation of a synchronization command begins, using PS = (Px - L - Ld, Py), and transmits the synchronization start position PS to the synchronization start position arrival determination unit 11 as the synchronization start position. In this way, in embodiment 6, the learning unit 21 uses the neural network to derive the delay amount Ld, which is one of the parameters used when performing tracking control.

The learning unit 21 may be located in any position. The learning unit 21 may be located inside or outside the tracking control device 50A. The learning unit 21 may be located, for example, in a server.

Here, the learning unit 21 will be described in detail. The learning unit 21 acquires a combination of the target position P, the conveying speed, and the control system parameters (hereinafter sometimes referred to as combination information) and the delay amount Ld corresponding to this combination information (first combination information). The delay amount Ld acquired by the learning unit 21 may be the delay amount Ld calculated by the synchronization start position calculation unit 10A of embodiment 3, or may be the delay amount Ld calculated by another device.

The learning unit 21 learns the delay amount Ld corresponding to the combination information based on learning data created based on the combination of the combination information and the delay amount Ld. In other words, the learning unit 21 learns the delay amount Ld for the combination information based on the learning data. That is, the learning unit 21 generates a trained model (such as a neural network) that infers the delay amount Ld from the combination information. Here, the training data is data in which the combination information and the delay amount Ld are associated with each other. The learning unit 21 stores the trained model it has generated.

The learning unit 21 learns the delay amount Ld corresponding to the combination information, for example, using so-called supervised learning in accordance with a neural network model. Here, supervised learning refers to a method in which data sets (learning data) of inputs and results (labels) are provided to the learning unit 21, which then learns the features contained in the learning data and infers the results from the inputs.

A neural network consists of an input layer consisting of multiple neurons, an intermediate layer (hidden layer) consisting of multiple neurons, and an output layer consisting of multiple neurons. The intermediate layer may be one layer or two or more layers.

For example, in a three-layer neural network, when multiple input data are input to the input layer, the values are multiplied by weights and input to the middle layer. The results are then multiplied by further weights and output from the output layer. This output result changes depending on the value of the weights.

The neural network used by the learning unit 21 in Figure 10 learns the delay amount Ld corresponding to the combination information through so-called supervised learning, in accordance with learning data created based on a combination of the combination information and the delay amount Ld. In other words, the neural network used by the learning unit 21 learns the delay amount Ld corresponding to the combination information through so-called supervised learning, in accordance with the combination information and delay amount Ld created based on the combination of the acquired first input and second input (correct answer).

In other words, the neural network learns by inputting combination information, which is the first input, and adjusting the weights so that the result output from the output layer approaches the second input (correct answer). Specifically, the neural network learns by inputting combination information into the input layer and adjusting the weights so that the result output from the output layer approaches the delay amount Ld.

The neural network learns the correspondence between combination information and delay amount Ld, thereby generating a trained model that can output an appropriate delay amount Ld when combination information is input. In this way, the learning unit 21 learns a trained model that can output a correct delay amount Ld when combination information is input. By performing the above-described learning, the learning unit 21 generates a trained model represented by a neural network and stores the neural network.

The learning unit 21 acquires combination information when inferring the delay amount Ld. When the actual robot 6 is controlled, the learning unit 21 infers the delay amount Ld corresponding to the combination information using a trained model, which is a trained neural network. In other words, by inputting the combination information into the trained model, the learning unit 21 can output an appropriate delay amount Ld inferred from the combination information.

In this way, the combination of the combination information and the delay amount Ld is the data used during learning, and the combination information is the data used during inference. The tracking control device 50A of embodiment 6 learns a learned model based on the combination of the combination information and the delay amount Ld, and then infers the delay amount Ld by applying the combination information to the learned model. As a result, after learning the learned model, the tracking control device 50A of embodiment 6 is able to infer the delay amount Ld using the learned model.

In the sixth embodiment, the case where the learning unit 21 generates a trained model and outputs an appropriate delay amount Ld using the trained model has been described, but the learning unit 21 may also acquire a trained model from another learning unit. In this case, the learning unit 21 outputs an appropriate delay amount Ld based on the trained model acquired from the other learning unit, etc.

Furthermore, the tracking control device 50A may use the target position P and the conveying speed as the combination information, and may not include control system parameters in the combination information. In other words, the tracking control device 50A may learn the correspondence between the combination of the target position P and the conveying speed and the delay amount Ld, and when controlling the robot 6, may infer the delay amount Ld based on the target position P and the conveying speed.

According to the sixth embodiment, the learning unit 21 learns the correspondence between the combination information and the delay amount Ld, and when controlling the robot 6, infers the delay amount Ld based on the combination information. This allows the synchronization start position calculation unit 10A to accurately calculate an appropriate synchronization start position. This allows the tracking control device 50A to accurately correct the effects of delays in the control system.

Embodiment 7.
Next, a seventh embodiment will be described with reference to Fig. 11. A tracking control device 50A of the seventh embodiment learns the correspondence between the operation start position of the robot 6, the transport speed, and the object position, which is the position of the object to be transported on the conveyor 32, and the target position P, and when controlling the robot 6, infers the target position P based on the operation start position, the transport speed, and the object position.

In the tracking control device 50A of embodiment 7, the target position determination unit 3 has a learning unit. The tracking control device 50A of embodiment 7 and the tracking control device 50A of embodiment 3 differ in the processing executed by the target position determination unit 3.

Figure 11 is a diagram showing the configuration of a learning unit provided in a tracking control device according to embodiment 7. The learning unit (learning device) 22 provided in the tracking control device 50A is arranged, for example, within the target position determination unit 3.

The second learning unit, learning unit 22, is equipped with a neural network and pre-learns the correspondence (second correspondence) between the combination of the operation start position, transport speed, and object position and the target position P. That is, in embodiment 7, the combination of the operation start position, transport speed, and object position is combination information (second combination information).

When the correspondence between the combination information and the target position P is learned, the target position P that minimizes the work time for each combination of operation start position, conveying speed, and object position is repeatedly calculated using a simulator.

The learning unit 22 performs learning of the neural network by using the operation start position, transport speed, and object position as inputs to the neural network, and the target position P that minimizes the work time corresponding to the input operation start position, transport speed, and object position as the output (teacher signal) of the neural network.

The learned neural network is stored in the target position determination unit 3. When the tracking control device 50A actually operates the robot 6, the learning unit 22 outputs the target position P from the neural network, which corresponds to the operation start position, transport speed, and object position input to the neural network. The target position determination unit 3 sends the target position P output from the neural network to the synchronization start timing determination unit 1 and the operation command generation unit 4. In this way, in embodiment 7, the learning unit 22 uses the neural network to derive the target position P, which can be considered a parameter when performing tracking control.

In this way, the information that learning unit 22 inputs and outputs during learning is different from that of learning unit 21, but the learning process by learning unit 22 is the same as that of learning unit 21. Also, the information that learning unit 22 inputs and outputs during inference is different from that of learning unit 21, but the inference process by learning unit 22 is the same as that of learning unit 21.

The learning unit 22 may be located in any position. The learning unit 22 may be located inside or outside the tracking control device 50A. The learning unit 22 may be located, for example, in a server.

In this way, in embodiment 7, the learning unit 22 learns the correspondence between the operation start position, transport speed, and object position and the target position P, and when controlling the robot 6, infers the target position P based on the operation start position, transport speed, and object position. This allows the target position determination unit 3 to accurately calculate an appropriate target position P, enabling the tracking control device 50A to further reduce the grasping error of the robot 6 and further shorten the operating time of the robot 6.

Here, we will explain the hardware configuration of the tracking control devices 50A to 50C. The tracking control devices 50A to 50C are realized by a processing circuit. This processing circuit may be a processor and memory that executes a program stored in memory, or it may be dedicated hardware. The processing circuit is also called a control circuit.

Figure 12 is a diagram showing an example of the configuration of a processing circuit when the processing circuit provided in the tracking control device according to embodiments 1 to 7 is realized by a processor and memory. Note that since the tracking control devices 50A to 50C have similar hardware configurations, the hardware configuration of the tracking control device 50A will be described here.

The processing circuit 90 shown in FIG. 12 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is configured with a processor 91 and a memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 92. In the processing circuit 90, each function is realized by the processor 91 reading and executing the program stored in the memory 92. In other words, the processing circuit 90 includes a memory 92 for storing a control program that results in the processing of the tracking control device 50A. This control program can also be said to be a program that causes the tracking control device 50A to execute each function realized by the processing circuit 90. This control program may be provided by a storage medium on which the program is stored, or by other means such as a communication medium.

Here, the processor 91 is, for example, a CPU (Central Processing Unit), processing device, arithmetic unit, microprocessor, microcomputer, or DSP (Digital Signal Processor). Furthermore, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), or EEPROM (Electrically EPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisk, or a DVD (Digital Versatile Disc).

Figure 13 is a diagram showing an example of a processing circuit when the processing circuit provided in the tracking control device according to embodiments 1 to 7 is realized by dedicated hardware. The processing circuit 93 shown in Figure 13 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these.

The processing circuits 90 and 93 may be implemented partly with dedicated hardware and partly with software or firmware. In this way, the processing circuits 90 and 93 can realize the above-mentioned functions using dedicated hardware, software, firmware, or a combination of these.

In addition, the synchronization start timing determination unit 1, synchronization command generation unit 2, target position determination unit 3, operation command generation unit 4, each axis control unit 5, gripping operation control unit 7, and synthesis unit 15 may be realized by separate processing circuits.

The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. Parts of the configuration may also be omitted or modified without departing from the spirit of the invention.

1, 1A Synchronization start timing determination unit, 2 Synchronization command generation unit, 3 Target position determination unit, 4 Operation command generation unit, 5 Each axis control unit, 6 Robot, 7 Grasping operation control unit, 8 Synchronization consideration acceleration/deceleration determination unit, 9 Interference influence determination unit, 10, 10A Synchronization start position calculation unit, 11 Synchronization start position arrival determination unit, 15 Synthesis unit, 21, 22 Learning unit, 31 Transported object, 32 Conveyor, 50A-50C Tracking control device, 90, 93 Processing circuit, 91 Processor, 92 Memory, A1 Interference consideration unnecessary area, P Target position, P0 Specific point, P1-Pk, Pm, Pn, PA, TP0, TP1 Points, PS Synchronization start position.

Claims (11)

a synchronization command generation unit that generates a synchronization command for synchronizing the operation of a mechanical system that performs work on a transport object with the operation of a transport device that transports the transport object, based on a synchronization start timing that is a timing for starting the synchronization determined based on a transport speed of the transport object;
an operation command generating unit that generates a mechanical system operation command that is a command to move the mechanical system to a target position;
a synthesizing unit that synthesizes the synchronization command and the mechanical system operation command to generate a synthesized command and outputs the generated synthesized command;
Equipped with
the synchronization command generation unit generates the synchronization command to start the synchronization before the mechanical system reaches the target position.
A tracking control device characterized by: a synchronization start timing determination unit that determines the synchronization start timing based on the target position, the position of the object to be conveyed, and the conveying speed;
2. The tracking control device according to claim 1, the synchronization start timing determination unit determines a time point when the transport object reaches a synchronization start position, which is a position a predetermined specific distance ahead of the target position, as the synchronization start timing, which is a timing to start the synchronization, and outputs a synchronization start command indicating the synchronization start timing to the synchronization command generation unit;
the synchronization command generation unit generates the synchronization command upon receiving the synchronization start command.
3. The tracking control device according to claim 2. the synchronization start timing determination unit determines the specific distance to be a distance calculated based on the product of a time taken for the mechanical system to accelerate and a speed at which the mechanical system accelerates when synchronizing, and determines the synchronization start position based on the specific distance.
4. The tracking control device according to claim 3. the synchronization command generation unit generates a speed command to the mechanical system, which is specified by the synchronization command, using a square wave speed command and a moving average filter;
5. A tracking control device according to claim 1, wherein the tracking control device comprises: a first input/output terminal; the synchronization start timing determination unit determines the synchronization start position based on a control system parameter used in a control system of the mechanical system.
5. The tracking control device according to claim 4. an acceleration/deceleration determination unit that determines acceleration and deceleration parameters that are parameters for acceleration and deceleration when the mechanical system is synchronized in accordance with the synchronization command;
the acceleration/deceleration determination unit determines the acceleration/deceleration parameters within a range that satisfies constraints on each axis of the mechanical system, based on the synchronization command that is combined with the mechanical system operation command;
the operation command generation unit generates the mechanical system operation command based on the acceleration/deceleration parameter.
7. A tracking control device according to claim 1, wherein the tracking control device is a tracking control device for controlling a tracking operation of a moving object. the synchronization start timing determination unit sets the synchronization start timing to a timing when the mechanical system reaches an interference consideration unnecessary area, which is an area where there is no possibility that the mechanical system will interfere with an object, and when the transported object reaches the synchronization start position.
4. The tracking control device according to claim 3. a first learning unit configured to learn a first correspondence relationship between first combination information, which is a combination of the control system parameters, the target position, and the transport speed, and an amount of delay in the operation of the mechanical system;
the first learning unit, upon receiving the first combination information, infers the delay amount corresponding to the first combination information by using the first correspondence relationship;
the synchronization start timing determination unit determines the synchronization start position based on the estimated delay amount.
7. A tracking control device according to claim 6. a second learning unit configured to learn a second correspondence relationship between second combination information, which is a combination of an operation start position of the mechanical system, the transport speed, and an object position, which is a position of the transport object on the transport device, and the target position;
the second learning unit, upon receiving the second combination information, infers the target position corresponding to the second combination information by using the second correspondence relationship;
10. A tracking control device according to claim 1, wherein the tracking control device is a tracking control device for controlling a moving object. a synchronization command generating step in which the tracking control device generates a synchronization command for synchronizing the operation of a mechanical system that performs work on the transported object with the operation of a transport device that transports the transported object, based on a synchronization start timing that is a timing for starting the synchronization determined based on a transport speed of the transported object;
an operation command generating step in which the tracking control device generates a mechanical system operation command which is a command to move the mechanical system to a target position;
a combining step in which the tracking control device combines the synchronization command and the mechanical system operation command to generate a combined command and outputs the generated combined command;
Including,
In the synchronization command generating step, the tracking control device generates the synchronization command for starting the synchronization before the mechanical system reaches the target position.
A tracking control method comprising: