JP6947083B2 - Robot control device and robot control method - Google Patents

Description

The present invention relates to a robot control device and a robot control method, and more particularly to a robot control device and a robot control method for controlling a plurality of robots in coordination with each other.

Conventionally, as a robot control method of this kind, for example, as disclosed in Patent Document 1 (Japanese Unexamined Patent Publication No. 08-161015), each joint axis of an articulated robot is independently controlled, and each joint axis is controlled. It is known that the control parameters for independent control are changed in real time according to the operation. In particular, the document discloses that the control parameters are changed according to the assembly work for each arm of the dual arm. As a result, it is possible to provide a copying mechanism that escapes when a large external force is applied to one arm in cooperative work, and it is possible to prevent collisions between the arms and destruction of parts to be assembled.

Japanese Unexamined Patent Publication No. 08-161015

By the way, at a work site where a robot is used, various types of work objects (including work-in-process and finished products being assembled), particularly work objects having different weights (mass) are handled. Therefore, in order to handle various types of work objects, it is considered necessary to change the number of robots according to the weight of the work objects. However, Patent Document 1 does not describe this point at all.

Therefore, an object of the present invention is to provide a robot control device and a robot control method suitable for handling various work objects having different weights.

In order to solve the above problems, the robot control device of this disclosure is
A robot control device that controls multiple robots in coordination with each other.
A weight determination unit that determines whether the weight of the work object is heavier than the predetermined payload of one first robot, and a weight determination unit.
When the weight of the work object is less than the payload of the first robot, the independent control of handling the work object only by the first robot is selected, while the weight of the work object is the first. When it is equal to or more than the payload of the robot, the cooperative control in which the work object is handled by the first robot and the second robot different from the first robot is selected, and the weight of the work object is higher than the weight of the work object. It is equipped with a control unit that keeps the total payload of the first and second robots large .
The second robot includes a force sensor that detects the force that the gripper of the second robot receives from the work object.
The control unit controls the position of the first robot when performing the cooperative control, while the force sensor cancels out the force generated by gravity on the work object for the second robot. It is characterized in that the gripper of the second robot is made to follow the gripper of the second robot so as to perform a copying operation so that the received force becomes zero.

As used herein, "handling" a work object broadly includes operations such as translation and / or rotation of the work object, assembly to another work object, and the like.

Further, the first robot is one robot having a predetermined payload. The second robot may be one robot having a predetermined payload, or may be a plurality of robots having a predetermined payload.

In the robot control device of the present disclosure, the weight determination unit determines whether or not the weight of the work object is larger than the predetermined payload of the first robot. When the weight of the work object is less than the payload of the first robot, the control unit selects independent control in which the work object is handled only by the first robot. Here, since the weight of the work object is less than the payload of the first robot, the work object can be handled without any trouble only by the first robot. Further, since only the first robot (only one) is controlled by the independent control, the control is easily performed. On the other hand, when the weight of the work object is equal to or greater than the payload of the first robot, the control unit uses the first robot and a second robot different from the first robot to perform the work object. Select the cooperative control to be handled so that the total payload of the first and second robots is larger than the weight of the work object. Here, since the total payload of the first and second robots is larger than the weight of the work object, the work object can be handled by the first and second robots without any trouble. .. As described above, this robot control device is suitable for handling various work objects having different weights.

In particular, in this robot control device, the control unit controls the position of the first robot when performing the cooperative control. Therefore, the first robot is normally controlled by general position control. On the other hand, when the control unit performs the coordinated control, the force received by the force sensor with respect to the second robot in a state of canceling the force generated by gravity on the work object becomes zero. Is made to perform a copying operation in which the gripper of the second robot follows the work object. Therefore, the first robot and the second robot can be controlled in cooperation with each other. As a result, the work object can be handled stably.

As used herein, the "gripper" of a robot refers to a portion that grips a work object.

Further, "position control" means control such that the target value of the servo mechanism included in the robot is a position or an angle.

In the robot control device of one embodiment,
A plurality of the above second robots are provided,
The control unit is characterized in that, when performing the cooperative control, the plurality of second robots are made to perform the imitation operation, respectively.

In the robot control device of this one embodiment, since there are a plurality of the second robots, it is possible to easily make the total payload of the first and second robots larger than the weight of the work object. can. Further, when the cooperative control is performed, the control unit causes each of the plurality of second robots to perform the imitation operation. Therefore, the first robot and the plurality of second robots can be coordinated and controlled with each other. As a result, the work object can be handled stably.

In the robot control device of one embodiment,
A storage unit that stores the types of multiple work objects and the weight of each work object as a correspondence table in association with each other.
It is equipped with an input unit for inputting the type of the work object.
The weight determination unit knows the weight of the work object corresponding to the above type by referring to the above correspondence table based on the type of the work object input by the input unit, and the weight of the work object is calculated. It is characterized in that it is determined whether or not it is larger than the payload of the first robot.

In the robot control device of this embodiment, when the user inputs the product type of the work object by the input unit, the weight determination unit uses the input unit to input the product type of the work object. By referring to the correspondence table, the weight of the work object corresponding to the above product type is known. Then, the weight determination unit determines whether or not the weight of the work object is larger than the payload of the first robot. Therefore, the user can save the trouble of measuring the weight of the work object one by one at the work site.

In another aspect, the robotic control method of this disclosure
It is a robot control method that controls multiple robots in cooperation with each other.
Judging whether the weight of the work object is heavier than the predetermined payload of one first robot,
When the weight of the work object is less than the payload of the first robot, the independent control of handling the work object only by the first robot is selected, while the weight of the work object is the first. When it is equal to or more than the payload of the robot, the cooperative control in which the work object is handled by the first robot and the second robot different from the first robot is selected, and the weight of the work object is higher than the weight of the work object. It is characterized in that the total payload of the first and second robots is large.

In the robot control method of the present disclosure, first, it is determined whether or not the weight of the work object is heavier than the predetermined payload of the first robot. When the weight of the work object is less than the payload of the first robot, the independent control in which the work object is handled only by the first robot is selected. Here, since the weight of the work object is less than the payload of the first robot, the work object can be handled without any trouble only by the first robot. Further, since only the first robot (only one) is controlled, the control is easily performed. On the other hand, when the weight of the work object is equal to or greater than the payload of the first robot, cooperative control is performed in which the work object is handled by the first robot and a second robot different from the first robot. Select to make the total payload of the first and second robots larger than the weight of the work object. Here, since the total payload of the first and second robots is larger than the weight of the work object, the work object can be handled by the first and second robots without any trouble. .. As described above, this robot control method is suitable for handling various work objects having different weights.

As is clear from the above, the robot control device and the robot control method of the present disclosure are suitable for handling various work objects having different weights.

It is a figure which shows the block structure of the robot control apparatus of one Embodiment of this invention. It is a figure which shows the operation flow of the robot control method of one Embodiment performed by the said robot control device. It is a figure which shows the mode in which a certain finished product is assembling from two parts at the work site where two robots are used. It is a figure which shows the state which the said finished product was assembled at the work site where two robots are used. It is a figure which shows the mode in which the said finished product is conveyed from an assembly table to a payout table. It is a figure which shows the state which the said finished product is placed on the payout table. It is a figure which shows the mode in which another finished product is assembling from two parts at the work site where two robots are used. It is a figure which shows the state which the said finished product was assembled at the work site where two robots are used. It is a figure which shows the mode in which the said finished product is conveyed from an assembly table to a payout table. It is a figure which shows the state which the said finished product is placed on the payout table.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a block configuration of a robot control device 10 according to an embodiment of the present invention. The robot control device 10 is devised to control a plurality of robots (in this example, the first robot 101 and a second robot 102 different from the first robot 101) in coordination with each other.

In this example, the first robot 101 and the second robot 102 are composed of a 6-axis (6-control axis) articulated robot having grippers 101 g and 102 g as shown in FIG. 3 (A), respectively. The first robot 101 and the second robot 102 grip the work object 900 (shown in FIG. 1) by the grippers 101 g and 102 g, respectively, and carry the work object 900 including translation and / or rotation. , Can be assembled to another work object. In this example, the payload of the first robot 101 (referred to as TW1) and the payload of the second robot 102 (referred to as TW2) are both defined as 5 kg. .. That is, in this example, TW1 = TW2 = 5 kg.

As shown in FIG. 3A, in this example, a force sensor 103 for detecting the force received by the gripper 102g from the work object 900 is mounted on a portion of the second robot 102 near the gripper 102g. .. This force sensor 103 is used when performing a copying operation described later.

As shown in FIG. 1, in this example, the robot control device 10 includes an input unit 11, a storage unit 12, a first robot control unit 20, a central control unit 30, and a second robot control unit 40. .. In this example, the first robot control unit 20, the central control unit 30, and the second robot control unit 40 constitute the control unit.

The input unit 11 is composed of a teaching pendant in this example. In this example, the input unit 11 is particularly used to input the type of work object 900 to be handled by the first robot 101 and the second robot 102.

The storage unit 12 is made of a non-volatile semiconductor memory in this example. In this example, the storage unit 12 associates the product type and the weight (represented by the reference numeral W) with each work object 900 to be handled by the first robot 101 and the second robot 102, and shows the table below. It is stored (stored) as a correspondence table such as 1. These types and weights are input in advance via the input unit 11. By referring to this correspondence table, the central control unit 30 can see, for example, the weight W of the part A is 3 kg, the weight W of the part B is 1 kg, the weight W of the part B'is 4 kg, and the weight W of the finished product C is 4 kg. It can be known that the weight W of the finished product C'is 7 kg.
(Table 1) Correspondence table between product type and weight

In this example, the first robot control unit 20 uses a 6-axis first robot 101 and a master information CV1 composed of 6 elements having the same number of axes as the number of axes, according to a first robot control program stored in a storage unit (not shown). Use to control. The master information CV1 is three elements representing the degree of freedom of translation, X (position of the X axis), Y (position of the Y axis) and Z (position of the Z axis), and three elements representing the degree of freedom of rotation. Includes Yaw (yaw angle value), Pitch (pitch angle value) and Rot (roll angle value). The values of each element of the master information CV1 are sequentially updated at regular intervals in this example, whereby each axis of the first robot 101 is driven.

In order to control the first robot 101 and the second robot 102 in coordination with each other, the central control unit 30 controls the first robot control unit 20 and the second robot control unit 40 by the control signals CL1 and CL2. Synchronize. In this example, the central control unit 30 performs either independent control in which the work object 900 is handled only by the first robot 101 or cooperative control in which the work object 900 is handled by the first robot 101 and the second robot 102. , Switch and select (details will be described later).

In this example, the second robot control unit 40 uses a second robot 102 with six axes and a slave information CV2 composed of six elements having the same number of axes as the number of axes, according to a second robot control program stored in a storage unit (not shown). Use to control. In this example, the second robot control unit 40 receives the output signal FS of the force sensor 103 with respect to the second robot 102, and the force received by the force sensor 103 (the force received by the gripper 102 g from the work object 900) is applied. It is possible to perform a copying operation in which the gripper 102g of the second robot 102 is made to follow the work object 900 so as to be zero. The second robot control program is designed to offset the force generated by gravity with respect to the work object 900.

Such a first robot control unit 20, a central control unit 30, and a second robot control unit 40 are composed of a processor that operates according to a program.

FIG. 2 shows an operation flow of the robot control method of one embodiment performed by the robot control device 10 described above.

First, as shown in step S1 of FIG. 2, the central control unit 30 refers to the above-mentioned correspondence table (Table 1) based on the type of the work object 900 input by the input unit 11. Know the weight W of the work object 900 corresponding to the product type.

Next, as shown in step S2 of FIG. 2, the central control unit 30 acts as a weight determination unit, and whether or not the weight W of the work object 900 is larger than the payload TW1 of one first robot 101. To judge. As a result, the user can save the trouble of measuring the weight W of the work object 900 at the work site one by one.

Here, if the weight W of the work object 900 is less than the payload TW1 of the first robot 101 (NO in step S2 of FIG. 2), the central control unit 30 controls as shown in step S3 of FIG. It works as a unit and selects an independent control that handles the work object 900 only by the first robot 101. Here, since the weight W of the work object 900 is less than the payload TW1 of the first robot 101, there is no problem in using the work object 900 only by the first robot 101 (controlled by the first robot control unit 20). Can be handled. Further, since only the first robot 101 (only one robot) is controlled by the independent control, the control can be easily performed.

On the other hand, if the weight W of the work object 900 is equal to or greater than the payload TW1 of the first robot 101 (YES in step S2 of FIG. 2), the central control unit 30 is the control unit as shown in step S4 of FIG. To select the cooperative control in which the work object 900 is handled by the first robot 101 and the second robot 102. As a result, the total payload of the first and second robots 101 and 102 (this is represented by the reference numeral TWS) is larger than the weight W of the work object 900. Here, since the total payload TWS of the first and second robots 101 and 102 is larger than the weight W of the work object 900, the work object 900 is set to the first and second robots 101 and 102 ( Each can be handled without any trouble by the first robot control unit 20 and the second robot control unit 40).

More specifically, for example, as shown in FIG. 3A, the first robot 101 and the second robot 102 grip the parts A and B as the work object 900, respectively, and these parts are held on the assembly table 800. It is assumed that A and the component B are combined with each other as shown by the arrow AS (assembly process). At this time, since the weight W of each part A is 3 kg, the payload of the first robot 101 is less than TW1 (= 5 kg). Similarly, since the weight W of the component B is 1 kg, it is less than the payload TW2 (= 5 kg) of the second robot 102. Therefore, the first robot 101 and the second robot 102 can handle the parts A and the parts B, respectively, without any trouble, not to mention the operation flow of FIG. However, the operation flow of FIG. 2 may be applied to this assembly process to independently control the first robot 101 and the second robot 102 as the "first robot" in the operation flow of FIG. 2 (FIG. 2). Steps S1 to S3).

Next, as shown in FIG. 3B, it is assumed that the finished product C is produced on the assembly table 800 by the above assembly process. The product type is input by the input unit 11 for the finished product C, and the central control unit 30 knows that the weight W is 4 kg by referring to the above-mentioned correspondence table (Table 1) (step in FIG. 2). S1). Next, the central control unit 30 functions as a weight determination unit to determine whether or not the weight W (= 4 kg) of the finished product C is larger than the payload TW1 (= 5 kg) of one first robot 101. (Step S2 in FIG. 2). At this time, since the weight W (= 4 kg) of the finished product C is less than the payload TW1 (= 5 kg) of the first robot 101 (NO in step S2 of FIG. 2), the central control unit 30 works as a control unit. Then, the independent control in which the finished product C is handled only by the first robot 101 is selected (step S3 in FIG. 2). Then, as shown in FIGS. 3C to 3D (a view showing the view from above), only the first robot 101 controlled by the first robot control unit 20 is a payout table from the assembly table 800 as shown by an arrow D. The finished product C is transported (translated in this example) onto the 880 (payout process). At this time, the control of the first robot 101 by the first robot control unit 20 is easily performed by general position control.

In another example, as shown in FIG. 4A, the first robot 101 and the second robot 102 grip the part A and the part B'as the work object 900, respectively, and the parts A on the assembly table 800. And the component B are combined with each other as shown by the arrow AS'(assembly process). At this time, since the weight W of each part A is 3 kg, the payload of the first robot 101 is less than TW1 (= 5 kg). Similarly, since the weight W of the component B'is 4 kg, it is less than the payload TW2 (= 5 kg) of the second robot 102. Therefore, the first robot 101 and the second robot 102 can handle the parts A and the parts B', respectively, without any trouble, not to mention the operation flow of FIG. However, as in the case of FIG. 3A, the operation flow of FIG. 2 is applied to this assembly process, and the first robot 101 and the second robot 102 are independently controlled as "first robots" in the operation flow of FIG. 2, respectively. It may be done (steps S1 to S3 of FIG. 2).

Next, as shown in FIG. 4B, it is assumed that the finished product C'is produced on the assembly table 800 by the above assembly process. The product type is input by the input unit 11 for the finished product C', and the central control unit 30 knows that the weight W is 7 kg by referring to the above-mentioned correspondence table (Table 1) (FIG. 2). Step S1). Next, the central control unit 30 functions as a weight determination unit to determine whether or not the weight W (= 7 kg) of the finished product C'is larger than the payload TW1 (= 5 kg) of one first robot 101. Judgment (step S2 in FIG. 2). At this time, since the weight W (= 7 kg) of the finished product C'is equal to or greater than the payload TW1 (= 5 kg) of the first robot 101 (YES in step S2 of FIG. 2), the central control unit 30 serves as a control unit. It works and selects the coordinated control in which the finished product C'is handled by the first robot 101 and the second robot 102 (step S4 in FIG. 2). As a result, the total payload TWS (= 10 kg) of the first and second robots 101 and 102 is set to be larger than the weight W (= 7 kg) of the finished product C'. Then, as shown in FIGS. 4C to 4D (a view showing the view from above), the first robot 101 controlled by the first robot control unit 20 and the second robot 102 controlled by the second robot control unit 40 In cooperation with, the finished product C'is transported (translated in this example) from the assembly table 800 to the delivery table 880 as shown by the arrow D'(delivery process). Here, since the total payload TWS (= 10 kg) of the first and second robots 101 and 102 is larger than the weight W (= 7 kg) of the finished product C', the finished product C'is first. And the second robots 101 and 102 can handle it without any trouble.

In the payout process (when cooperative control is performed) of FIGS. 4C to 4D, the first robot control unit 20 controls the position of the first robot 101 in response to a command from the central control unit 30. Therefore, the first robot 101 is normally controlled by general position control. On the other hand, in response to the command from the central control unit 30, the second robot control unit 40 receives the output signal FS of the force sensor 103 for the second robot 102, and the force received by the force sensor 103 becomes zero. As described above, the finished product C'is subjected to a copying operation in which the gripper 102g of the second robot 102 is made to follow. Therefore, the first robot 101 and the second robot 102 can be coordinated and controlled. As a result, the finished product C'can be handled stably.

In the above example, the number of the second robot 102 is assumed to be one, but the present invention is not limited to this. For example, when the weight W of the finished product C ″ as the work object 900 is 12 kg (see the above correspondence table (Table 1)), another robot having the same specifications as the above-mentioned second robot 102 is prepared. The finished product C ″ may be handled by a total of three robots 101 and two second robots 102 and 102. In such a case, the total payload TWS (= 15 kg) of the three robots 101 and the second robots 102 and 102 is easily larger than the weight W (= 12 kg) of the finished product C ″. Therefore, the finished product C "can be handled by the first robot 101 and the second robots 102 and 102 without any trouble. Further, in this case, the second robot control unit 40 receives a command from the central control unit 30 so that the force received by the force sensor 103 for each of the two second robots 102 and 102 becomes zero. It is desirable to perform a copying operation in which the gripper 102g of the second robot 102 is made to follow the finished product C'. As a result, the first robot 101 can be controlled by coordinating the two second robots 102 and 102. As a result, the finished product C "can be handled stably.

Further, for example, when the weight W of the work object 900 exceeds 15 kg, three or more second robots 102, 102, 102, ... Are prepared, and the work object 900 is divided into the first robot 101 and three or more. It may be handled by the second robot 102, 102, 102, ....

As described above, the robot control device 10 is suitable for handling various work objects 900 having different weights.

In the above example, the number of control axes of the first robot 101 and the second robot 102 is assumed to be 6 axes, respectively, but the present invention is not limited to this. The first robot 101 and the second robot 102 may be robots with less than 6 axes, for example, a 5-axis horizontal articulated robot, a 4-axis parallel link robot, or the like, depending on the type of work.

The above embodiment is an example, and various modifications can be made without departing from the scope of the present invention. The plurality of embodiments described above can be established independently, but combinations of the embodiments are also possible. Further, although various features in different embodiments can be established independently, it is also possible to combine features in different embodiments.

10 Robot control device 11 Input unit 12 Storage unit 20 First robot control unit 30 Central control unit 40 Second robot control unit 103 Force sensor

Claims (4)

A robot control device that controls multiple robots in coordination with each other.
A weight determination unit that determines whether the weight of the work object is heavier than the predetermined payload of one first robot, and a weight determination unit.
When the weight of the work object is less than the payload of the first robot, the independent control of handling the work object only by the first robot is selected, while the weight of the work object is the first. When it is equal to or more than the payload of the robot, the cooperative control in which the work object is handled by the first robot and the second robot different from the first robot is selected, and the weight of the work object is higher than the weight of the work object. It is equipped with a control unit that keeps the total payload of the first and second robots large .
The second robot includes a force sensor that detects the force that the gripper of the second robot receives from the work object.
The control unit controls the position of the first robot when performing the cooperative control, while the force sensor cancels out the force generated by gravity on the work object for the second robot. A robot control device characterized in that a copying operation is performed so that the gripper of the second robot follows the work object so that the received force becomes zero. In the robot control device according to claim 1,
A plurality of the above second robots are provided,
The control unit is a robot control device, characterized in that, when performing the cooperative control, the plurality of second robots are made to perform the imitation operation, respectively. In the robot control device according to claim 1 or 2.
A storage unit that stores the types of multiple work objects and the weight of each work object as a correspondence table in association with each other.
It is equipped with an input unit for inputting the type of the work object.
The weight determination unit knows the weight of the work object corresponding to the above type by referring to the above correspondence table based on the type of the work object input by the input unit, and the weight of the work object is determined. A robot control device for determining whether or not the weight of the first robot is larger than the payload of the first robot. It is a robot control method that controls multiple robots in cooperation with each other.
Judging whether the weight of the work object is heavier than the predetermined payload of one first robot,
When the weight of the work object is less than the payload of the first robot, the independent control of handling the work object only by the first robot is selected, while the weight of the work object is the first. When it is equal to or more than the payload of the robot, the cooperative control in which the work object is handled by the first robot and the second robot different from the first robot is selected, and the weight of the work object is higher than the weight of the work object. In addition to making the total payload of the first and second robots large ,
The second robot includes a force sensor that detects the force that the gripper of the second robot receives from the work object.
When performing the cooperative control, the position of the first robot is controlled, while the force received by the force sensor is zero for the second robot in a state where the force generated by gravity with respect to the work object is offset. A robot control method, characterized in that a copy operation is performed so that the gripper of the second robot follows the work object so as to be.

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