JP2019150918A - Robot control device and robot control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot control device and a robot control method suitable for handling various work objects having different weights. SOLUTION: It is determined whether or not the weight W of the work object is larger than the predetermined payload TW1 of one first robot (S2). When the weight W of the work object is less than the payload TW1 of the first robot, the independent control of handling the work object only by the first robot is selected (S3). On the other hand, when the weight W of the work object is equal to or greater than the payload TW1 of the first 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. , The total payload of the first and second robots is set to be larger than the weight W of the work object (S4). [Selection diagram] Fig. 2

Description

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

  Conventionally, as this type of robot control method, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 08-161015), each joint axis of an articulated robot is controlled independently, and each joint axis is controlled. There is known a method in which control parameters for independent control are changed in real time according to the operation. In particular, this document discloses that the control parameter is changed for each arm of the double arm according to the assembly work. Accordingly, it is possible to provide a copying mechanism that escapes when a large external force is applied to one of the arms in a cooperative operation, and prevents the arms from colliding with each other and the parts to be assembled to be destroyed.

Japanese Patent Laid-Open No. 08-161015

  By the way, in a work site where a robot is used, various types of work objects (including work-in-progress products being assembled, finished products, etc.), particularly work objects having different weights (mass) are handled. For this reason, 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 anything about that point.

  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 apparatus that controls a plurality of robots in cooperation with each other,
A weight determination unit for determining whether the weight of the work object is larger than a predetermined portable weight of one first robot;
When the weight of the work object is less than the transportable weight of the first robot, single control for handling the work object only by the first robot is selected, while the weight of the work object is the first weight. When the weight is equal to or greater than the transportable weight of the robot, the cooperative control for handling the work object by the first robot and a second robot different from the first robot is selected, and the weight is larger than the weight of the work object. And a control unit configured to make the total payload of the first and second robots large.

  In this specification, “handling” a work object broadly includes work including parallel movement and / or rotation of the work object, assembly to another work object, and the like.

  Further, the first robot is a single robot having a predetermined weight. The second robot may be a single robot with a predetermined payload, or may be a plurality of robots with predetermined payloads.

  In the robot control apparatus according to the present disclosure, the weight determination unit determines whether the weight of the work object is larger than a predetermined portable weight of the first robot. When the weight of the work object is less than the transportable weight of the first robot, the control unit selects single 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 transportable weight of the first robot, the work object can be handled only by the first robot without any trouble. Further, since only the first robot (only one unit) is controlled by the single control, the control is easily performed. On the other hand, when the weight of the work object is greater than or equal to the transportable weight of the first robot, the control unit moves the work object by the first robot and a second robot different from the first robot. The cooperative control to be handled is selected so that the total payload of the first and second robots is greater than the weight of the work target. Here, since the total transportable weight 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. . Thus, this robot control apparatus is suitable for handling various work objects having different weights.

In the robot control apparatus of one embodiment,
The second robot includes a force sensor that detects a force received by the gripper of the second robot from the work object,
When performing the coordinated control, the control unit controls the position of the first robot, while the second robot is applied to the work target so that the force received by the force sensor becomes zero. A copying operation for causing the gripper of the second robot to follow is performed.

  In this specification, the “gripper” of the robot refers to a portion that holds a work target.

  “Position control” means control in which a target value of a servo mechanism included in the robot is a position or an angle.

  In the robot control apparatus according to this embodiment, the control unit controls the position of the first robot when performing the cooperative control. Therefore, the first robot is controlled as usual by general position control. On the other hand, when the control unit performs the cooperative control, the gripper of the second robot follows the work target so that the force received by the force sensor is zero for the second robot. The copying operation to be performed is performed. 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.

In the robot control apparatus of one embodiment,
A plurality of the second robots are provided,
The control unit causes the copying operation to be performed on each of the plurality of second robots when performing the cooperative control.

  In the robot control apparatus of this embodiment, since there are a plurality of the second robots, it is easy to make the total payload of the first and second robots larger than the weight of the work object. it can. In addition, the control unit causes the copying operation to be performed for each of the plurality of second robots when performing the cooperative control. Therefore, the first robot and the plurality of second robots can be controlled in cooperation with each other. As a result, the work object can be handled stably.

In the robot control apparatus of one embodiment,
A storage unit that associates and stores a plurality of work object types and the weight of each work object as a correspondence table;
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 product type by referring to the correspondence table based on the product type of the work object input by the input unit, and the weight of the work object is It is determined whether or not it is larger than the loadable weight of the first robot.

  In the robot control apparatus according to the embodiment, when the user inputs the type of the work object using the input unit, the weight determination unit is configured based on the type of the work object input by the input unit. By referring to the correspondence table, the weight of the work object corresponding to the product type is known. The weight determination unit determines whether the weight of the work object is larger than the portable weight of the first robot. Therefore, the user can save time and labor for measuring the weight of the work object at each work site.

In another aspect, the robot control method of this disclosure includes:
A robot control method for controlling a plurality of robots in cooperation with each other,
Determining whether the weight of the work object is greater than a predetermined payload of one first robot;
When the weight of the work object is less than the transportable weight of the first robot, single control for handling the work object only by the first robot is selected, while the weight of the work object is the first weight. When the weight is equal to or greater than the transportable weight of the robot, the cooperative control for handling the work object by the first robot and a second robot different from the first robot is selected, and the weight is larger than the weight of the work object. The total payload of the first and second robots is large.

  In the robot control method of this disclosure, first, it is determined whether or not the weight of the work object is larger than a predetermined portable weight of the first robot. When the weight of the work object is less than the portable weight of the first robot, single control for handling the work object only by the first robot is selected. Here, since the weight of the work object is less than the transportable weight of the first robot, the work object can be handled only by the first robot without any trouble. 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 transportable weight 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. The total load capacity of the first and second robots is selected to be greater than the weight of the work object. Here, since the total transportable weight 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. . Thus, this robot control method is suitable for handling various work objects having different weights.

  As apparent 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 configuration of the robot control apparatus of one Embodiment of this invention. It is a figure which shows the operation | movement flow of the robot control method of one Embodiment which the said robot control apparatus performs. It is a figure which shows the aspect in the middle of assembling a certain finished product from two parts in the work site where two robots are used. It is a figure which shows the state by which the said finished product was assembled in the work site where two robots are used. It is a figure which shows the aspect in which the said finished product is conveyed from an assembly stand to the payout stand. It is a figure which shows the state in which the said finished product was put on the payout stand. It is a figure which shows the aspect in the process of assembling another finished product from two components in the work site where two robots are used. It is a figure which shows the state by which the said finished product was assembled in the work site where two robots are used. It is a figure which shows the aspect in which the said finished product is conveyed from an assembly stand to the payout stand. It is a figure which shows the state in which the said finished product was put on the payout stand.

  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 apparatus 10 according to an embodiment of the present invention. The robot control apparatus 10 is devised to control a plurality of robots (in this example, the first robot 101 and another second robot 102 different from the robot) in cooperation with each other.

  In this example, the first robot 101 and the second robot 102 are each composed of a six-axis (six control axes) articulated robot having grippers 101g and 102g as shown in FIG. The first robot 101 and the second robot 102 hold the work object 900 (shown in FIG. 1) by the grippers 101g and 102g, respectively, and carry the work object 900 including parallel movement and / or rotation. It is possible to perform operations such as assembling to another work object. In this example, the portable weight of the first robot 101 (referred to as TW1) and the portable weight 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 that detects 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. . The force sensor 103 is used when a copying operation described later is performed.

  As shown in FIG. 1, the robot control apparatus 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. . In this example, the first robot control unit 20, the central control unit 30, and the second robot control unit 40 constitute a control unit.

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

In this example, the storage unit 12 is composed of a nonvolatile semiconductor memory. In this example, the storage unit 12 associates the type and weight (represented by the symbol W) for each work object 900 to be handled by the first robot 101 and the second robot 102, and shows the following table. It is stored (stored) as a correspondence table such as 1. These types and weights are input in advance via the input unit 11. The central control unit 30 refers to this correspondence table, 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 respectively known that the weight W of the finished product C ′ is 7 kg.
(Table 1) Correspondence table between varieties and weights

  In this example, according to a first robot control program stored in a storage unit (not shown), the first robot control unit 20 transmits the six-axis first robot 101 to the master information CV1 including the same number of six elements as the number of axes. Use to control. The master information CV1 is three elements representing X (X-axis position), Y (Y-axis position) and Z (Z-axis position), which are three elements representing the degree of freedom of translation, and the degree of freedom of rotation. Yaw (value of yaw angle), Pitch (value of pitch angle), and Roll (value of roll angle). In this example, the values of the elements of the master information CV1 are sequentially updated at a constant period, and thereby each axis of the first robot 101 is driven.

  The central control unit 30 performs control by the first robot control unit 20 and control by the second robot control unit 40 by the control signals CL1 and CL2 in order to control the first robot 101 and the second robot 102 in cooperation with each other. Synchronize. In this example, the central control unit 30 performs either single control for handling the work object 900 only by the first robot 101 or cooperative control for handling the work object 900 by the first robot 101 and the second robot 102. , Select by switching (details will be described later).

  In this example, the second robot control unit 40, in accordance with a second robot control program stored in a storage unit (not shown), displays the six-axis second robot 102 and slave information CV2 consisting of the same number of six elements as the number of axes. Use to control. In this example, 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 (the force received by the gripper 102g from the work object 900). The copying operation of causing the work object 900 to follow the gripper 102g of the second robot 102 can be performed so as to be zero. Note that the second robot control program is configured to cancel the generated force with respect to the force generated by gravity on the work object 900.

  The first robot control unit 20, the central control unit 30, and the second robot control unit 40 are configured by a processor that operates according to a program.

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

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

  Next, as shown in step S <b> 2 of FIG. 2, the central control unit 30 works as a weight determination unit, and whether or not the weight W of the work object 900 is larger than the portable weight TW <b> 1 of one first robot 101. Determine whether. Thereby, the user can omit the trouble of measuring the weight W of the work object 900 at each work site.

  Here, if the weight W of the work object 900 is less than the transportable weight TW1 of the first robot 101 (NO in step S2 of FIG. 2), the central control unit 30 performs control as shown in step S3 of FIG. The single control that handles the work object 900 only by the first robot 101 is selected. Here, since the weight W of the work object 900 is less than the transportable weight TW1 of the first robot 101, the work object 900 is not affected by the first robot 101 (controlled by the first robot control unit 20). It can be handled. Further, since only the first robot 101 (only one) is controlled by the single control, the control is easily performed.

  On the other hand, if the weight W of the work object 900 is not less than the transportable weight TW1 of the first robot 101 (YES in step S2 in FIG. 2), the central control unit 30 controls the control unit as shown in step S4 in FIG. The cooperative control in which the work object 900 is handled by the first robot 101 and the second robot 102 is selected. As a result, the total transportable weight of the first and second robots 101 and 102 (represented by TWS) is greater than the weight W of the work object 900. Here, since the total transportable weight 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 moved to the first and second robots 101 and 102 ( They can be handled without any trouble by the first robot controller 20 and the second robot controller 40, respectively.

  More specifically, for example, as shown in FIG. 3A, the first robot 101 and the second robot 102 respectively hold the parts A and B as the work object 900, and these parts on the assembly table 800. Assume that A and part B are combined with each other as shown by an arrow AS (assembly process). At this time, since the weight W of the part A is 3 kg, it is less than the transportable weight TW1 (= 5 kg) of the first robot 101. Similarly, since the weight W of the part B is 1 kg, it is less than the transportable weight TW2 (= 5 kg) of the second robot 102. Accordingly, the first robot 101 and the second robot 102 can handle the part A and the part B without any problem without depending on the operation flow of FIG. However, the operation flow of FIG. 2 may be applied to this assembling process, and the first robot 101 and the second robot 102 may be individually controlled as “first robot” in the operation flow of FIG. 2 (FIG. 2). Steps S1-S3).

  Next, as shown in FIG. 3B, it is assumed that a finished product C is manufactured on the assembly table 800 by the assembly process. The 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 correspondence table (Table 1) (step of FIG. 2). S1). Next, the central control unit 30 works as a weight determination unit to determine whether or not the weight W (= 4 kg) of the finished product C is larger than the portable weight 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 transportable weight TW1 (= 5 kg) of the first robot 101 (NO in step S2 in FIG. 2), the central control unit 30 works as a control unit. Then, single control for handling the finished product C only by the first robot 101 is selected (step S3 in FIG. 2). As shown in FIGS. 3C to 3D (views seen from above), only the first robot 101 controlled by the first robot control unit 20 is moved from the assembly table 800 as indicated by the arrow D. The finished product C is transported onto 880 (parallel movement in this example) (dispensing step). 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 respectively hold the part A and the part B ′ as the work object 900, and these parts A on the assembly table 800. And part B are combined with each other as shown by arrow AS '(assembly process). At this time, since the weight W of the part A is 3 kg, it is less than the transportable weight TW1 (= 5 kg) of the first robot 101. Similarly, since the weight W of the part B ′ is 4 kg, it is less than the transportable weight TW2 (= 5 kg) of the second robot 102. Accordingly, the first robot 101 and the second robot 102 can handle the part A and the part B ′ without hindrance, without needing to follow 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 individually controlled as the “first robot” in the operation flow of FIG. (Steps S1 to S3 in FIG. 2).

  Next, as shown in FIG. 4B, it is assumed that a finished product C ′ is produced on the assembly table 800 by the assembly process. The type of the finished product C ′ is input by the input unit 11, and the central control unit 30 knows that the weight W is 7 kg by referring to the above correspondence table (Table 1) (FIG. 2). Step S1). Next, the central control unit 30 functions as a weight determination unit to determine whether the weight W (= 7 kg) of the finished product C ′ is larger than the portable weight TW1 (= 5 kg) of one first robot 101. Judgment is made (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 transportable weight TW1 (= 5 kg) of the first robot 101 (YES in step S2 in FIG. 2), the central control unit 30 serves as the control unit. The cooperative control for handling the finished product C ′ by the first robot 101 and the second robot 102 is selected (step S4 in FIG. 2). As a result, the total transportable weight TWS (= 10 kg) of the first and second robots 101 and 102 is made larger than the weight W (= 7 kg) of the finished product C ′. Then, as shown in FIGS. 4C to 4D (views 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. And the finished product C ′ is conveyed (in this example, parallel movement) from the assembly table 800 onto the dispensing table 880 as shown by the arrow D ′ (dispensing step). Here, since the total transportable weight 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 used as the first product C ′. And it can be handled by the second robots 101 and 102 without any trouble.

  In the payout process (when cooperative control is performed) in 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 controlled as usual by general position control. On the other hand, in response to a 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 copying operation for causing the gripper 102g of the second robot 102 to follow the finished product C ′ is performed. Accordingly, the second robot 102 can be controlled in cooperation with the first robot 101. As a result, the finished product C ′ can be handled stably.

  In the above example, the number of the second robots 102 is 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 second robot 102 is prepared. Thus, the finished product C ″ may be handled by a total of three units including the first robot 101 and the two second robots 102 and 102. In such a case, the total transportable weight TWS (= 15 kg) of the first robot 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. In this case, in response to a command from the central control unit 30, the second robot control unit 40 causes the force received by the force sensor 103 to be zero for each of the two second robots 102 and 102. It is desirable to perform a copying operation for causing the gripper 102g of the second robot 102 to follow the finished product C ′. Thus, the first robot 101 can control the two second robots 102 and 102 in cooperation. 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 combined with the first robot 101 and three or more machines. You may handle with the 2nd robot 102,102,102, ....

  As described above, the robot control apparatus 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 6 axes, but the present invention is not limited to this. Depending on the type of work, the first robot 101 and the second robot 102 may be a robot with less than 6 axes, for example, a 5-axis horizontal articulated robot, a 4-axis parallel link robot, or the like.

  The above embodiments are merely examples, 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. In addition, various features in different embodiments can be established independently, but the features in different embodiments can be combined.

DESCRIPTION OF SYMBOLS 10 Robot control apparatus 11 Input part 12 Memory | storage part 20 1st robot control part 30 Central control part 40 2nd robot control part 103 Force sensor

Claims (5)

A robot control apparatus that controls a plurality of robots in cooperation with each other,
A weight determination unit for determining whether the weight of the work object is larger than a predetermined portable weight of one first robot;
When the weight of the work object is less than the transportable weight of the first robot, single control for handling the work object only by the first robot is selected, while the weight of the work object is the first weight. When the weight is equal to or greater than the transportable weight of the robot, the cooperative control for handling the work object by the first robot and a second robot different from the first robot is selected, and the weight is larger than the weight of the work object. A robot control apparatus comprising: a control unit configured to make a total payload of the first and second robots large. The robot control device according to claim 1,
The second robot includes a force sensor that detects a force received by the gripper of the second robot from the work object,
When performing the coordinated control, the control unit controls the position of the first robot, while the second robot is applied to the work target so that the force received by the force sensor becomes zero. A robot control apparatus for causing a copying operation to follow the gripper of the second robot. The robot control device according to claim 2, wherein
A plurality of the second robots are provided,
The control unit causes the copying operation to be performed for each of the plurality of second robots when performing the cooperative control. In the robot controller according to any one of claims 1 to 3,
A storage unit that associates and stores a plurality of work object types and the weight of each work object as a correspondence table;
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 product type by referring to the correspondence table based on the product type of the work object input by the input unit, and the weight of the work object is It is judged whether it is larger than the said load capacity of the said 1st robot, The robot control apparatus characterized by the above-mentioned. A robot control method for controlling a plurality of robots in cooperation with each other,
Determining whether the weight of the work object is greater than a predetermined payload of one first robot;
When the weight of the work object is less than the transportable weight of the first robot, single control for handling the work object only by the first robot is selected, while the weight of the work object is the first weight. When the weight is equal to or greater than the transportable weight of the robot, the cooperative control for handling the work object by the first robot and a second robot different from the first robot is selected, and the weight is larger than the weight of the work object. A robot control method characterized in that the total payload of the first and second robots is large.

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