JP2015142952A - Teaching method for component inserting operation of robot, and operation method of robot using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a teaching method for component inserting operation of a robot in which a teaching operator who is not familiar with teaching the robot can easily teach the inserting operation in such a case, and an operation method of the robot using the same.SOLUTION: As a method of teaching a track of insertion of an insert component gripped by an end effector 18 of a parallel link robot 10 into an insertion target member, there is provided a teaching method for component inserting operation of a robot that includes: teaching a track of an extracting operation for the insert component inserted into the insertion target member; and setting a track in the opposite direction from the taught track of the extracting operation for the insert component as a track of the component inserting operation.

Description

  The present invention relates to a teaching method of component insertion operation of a robot mainly for industrial use, and a robot operation method using the teaching method.

Conventionally, as a teaching method used for a component insertion robot system for inserting a workpiece held by an end effector attached to the tip of a robot arm into an object, there is a method using force display means. (See Patent Document 1)
In Patent Document 1, as shown in FIG. 12, the teaching worker sets the pressing force setting means 55 based on the pressing force displayed on the acting force display means 56 and the deviation displayed on the search movement amount display means 57. By operating, the pressing pressure can be adjusted during the search operation.

JP 2009-190147 A

  However, the conventional teaching method has a problem that the teaching operator of the robot needs to operate the pressure setting means based on the pressing force and the search movement amount, and requires skilled work. .

  The present invention solves the above-described conventional problems. For example, even when a teaching worker who is not accustomed to teaching a robot teaches an insertion work, a teaching method of a robot component insertion operation that can be easily taught. And an operation method of a robot using the same.

  In order to achieve the above object, the teaching method of the component insertion operation of the robot according to the present invention is a method for teaching a trajectory of inserting an insertion component gripped by an end effector provided on a movable plate of a robot into an inserted member. A trajectory of the extraction operation of the insertion part inserted into the member to be inserted is taught, and a trajectory in the direction opposite to the trajectory of the insertion operation of the inserted part is set as a trajectory of the component insertion operation. To do.

  According to the present invention, for example, even when a teaching worker who is not used to teaching a robot teaches an insertion work, the robot can be taught easily.

Schematic of the parallel link robot in Embodiment 1 of the present invention The figure which shows the teaching method in Embodiment 1 of this invention The figure which shows the teaching method by the hand gesture in Embodiment 1 of this invention The flowchart which shows the teaching method by the hand gesture in Embodiment 1 of this invention The figure which shows the insertion by the robot in Embodiment 1 of this invention The flowchart which shows the insertion by the robot in Embodiment 1 of this invention Explanatory drawing of the compliance control in Embodiment 2 of this invention Diagram showing the insertion model when the elastic center is placed at the center of the tip of the insertion part The figure which shows the insertion model at the time of arrange | positioning the elastic center in Embodiment 2 of this invention in the center of the tip of an insertion component The flowchart which shows the insertion by the robot in Embodiment 2 and 3 of this invention Block diagram of compliance control in Embodiment 3 of the present invention Figure of Example of Patent Document 1

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

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a parallel link robot 10 according to the first embodiment of the present invention.

  In FIG. 1, the parallel link robot 10 connects a fixed plate 12 and a movable plate 13 by a plurality of arms 14 and links 17. The parallel link robot 10 can control the operation of the movable plate 13 by controlling the position or posture of the arm 14 and the link 17.

  Since the movable plate 13 of the parallel link robot 10 according to the first embodiment has an extremely light structure without a heavy object such as its own drive source, the movable plate 13 can be operated at high speed or at a high speed. Useful for teaching. Note that “hand teaching” means that the user (teaching worker) directly moves the movable plate 13 while the power of the motor 15 is turned off, and the teaching operation by the user's hand is performed. In this method, the locus of the movable plate 13 is directly taught to the parallel link robot 10 by recording the locus with the encoder 15a. For example, an end effector 18 for gripping an object (inserted part) is attached to the movable plate 13.

  The arm 14 is connected to a main shaft of a motor 15 built in the fixed plate 12. The motor 15 includes an encoder 15a as a joint angle detection means. The angle of the arm 14 can be detected by using the encoder 15a. The motor 15 is an example of a power source of the parallel link robot 10. In FIG. 1, only one motor 15 is shown to simplify the drawing, but in the parallel link robot 10 of the first embodiment, the motor 15 is connected to each of the six arms 14. That is, the fixed plate 12 of the parallel link robot 10 according to the first embodiment includes six motors 15 and six encoders 15a.

  Here, in order to freely set the position and posture of the movable plate 13 of the parallel link robot 10 in a fixed coordinate system set in a predetermined space, the movable plate 13 has six degrees of freedom (movable axes). It is necessary to have. The parallel link robot 10 according to the first embodiment uses six sets including one arm 14, one link 17, and one motor 15, and independently controls the rotation of the motor 15 for each set. In this way, six degrees of freedom are realized. That is, the movable plate 13 is connected to the fixed plate 12 by three sets of six arms 14 and three sets of six links 17 so that the posture can be freely changed, and the position and posture of the movable plate 13 change according to the rotation angle of the six arms 14. To do. That is, the position and posture of the movable plate 13 are connected and restrained by the arm 14 and the link 17, and the position of the arm 14 and the link 17 is controlled by controlling the rotation angle of the arm 14 with a drive source such as the motor 15. And can change in space depending on the posture.

  One end of the arm 14 is attached to the fixed plate 12, and is configured to rotate in a predetermined plane around a predetermined axis. Both ends of the link 17 are connected by a joint portion 11 capable of freely turning in the space. The joint part 11 is an example of a bearing. One end of the link 17 is connected to the other end of the arm 14 by the joint portion 11, and the other end of the link 17 is connected to the movable plate 13 by the universal joint 21. The universal joint 21 is constituted by two intersecting joints.

  Next, a teaching method of component insertion operation in the parallel link robot 10 of the first embodiment will be described.

  As shown in FIG. 2, teaching is realized by holding a movable plate by hand and learning a trajectory to be moved.

  Here, the component insertion operation is an insertion operation of inserting an insertion component into a hole (inserted portion) of a member to be inserted. Here, description will be made with reference to the process diagram of FIG. 3 and the flowchart of FIG.

  First, as shown in FIG. 3 (1), an insertion part is previously placed in the hole of the member to be inserted (see S01 in FIG. 4). This state is an assembly completion state.

  Next, as shown in FIG. 3 (2), the movable plate 13 is brought close to the inserted part with the chuck of the end effector 18 provided on the movable plate 13 open, and as shown in FIG. 3 (3). The insert part is grasped by checking the end effector 18. Next, as shown in FIG. 3 (4), the inserted part is pulled out from the hole by a human hand. Next, as shown in FIG. 3 (5), the insertion part is moved to the part supply position by a human hand. Then, as shown in FIG. 3 (6), the insertion part is released by removing the chuck. Finally, as shown in FIG. 3 (7), the movable plate 13 is retracted by moving the movable plate 13 away from the insertion part and the supply position of the part. These trajectories of a series of pulling operations taught by the hand of the person are stored in the storage unit of the parallel link robot 10 (see S02 in FIG. 4).

  Then, the trajectory in the reverse direction of the extracting operation is set as the trajectory of the inserting operation (see S03 in FIG. 4).

  In this way, the teaching method for the component insertion operation of the robot according to the first embodiment teaches a teaching worker who is not familiar with the teaching of the robot by teaching the trajectory in the reverse direction of the extraction operation as the trajectory of the insertion operation. Even when teaching an insertion operation, it is possible to easily teach a robot.

  Furthermore, by using the motion trajectory taught in this way, the component insertion operation by the parallel link robot 10 and a series of operations (see FIG. 5) associated therewith can be repeatedly realized. FIG. 6 shows a flowchart of this operation. These operations are performed under the control of the control unit of the parallel link robot 10 (not shown).

  First, as shown in FIG. 5 (1), the movable plate 13 is brought close to the insertion part with the chuck of the end effector 18 opened (see S11 in FIG. 6), as shown in FIG. 5 (2). Then, the movable plate 13 is stopped at the position where the insertion part is gripped (see S12 in FIG. 6).

  Next, as shown in FIG. 5 (3), the insertion part is held by the chuck of the end effector 18 (see S13 in FIG. 6), and the movable plate 13 is inserted into the member to be inserted as shown in FIG. 5 (4). Move to near the hole (see S14 in FIG. 6).

  Next, as shown in FIG. 5 (5), the movable plate 13 is brought close to the hole (see S15 in FIG. 6), and as shown in FIG. The insertion operation is started (see S16 in FIG. 6), and the insertion operation is completed as shown in FIG. 5 (7) (see S17 in FIG. 6).

  Finally, as shown in FIG. 5 (8), the chuck of the end effector 18 is removed from the insertion part, and the movable plate 13 is retracted from the hole (see S18 in FIG. 6).

  Note that, among the parts inserting operation by the parallel link robot 10 shown in FIGS. 5 (1) to 5 (8) and a series of operations associated therewith, particularly from FIG. 5 (5), which is an embodiment of the present invention. The operation shown in FIG. 5 (7) is a highly effective operation using the part insertion trajectory taught by the teaching method of the present embodiment described with reference to FIGS. Also, the teaching method for the operations shown in FIGS. 5 (1) to 5 (4) and the operation shown in FIG. 5 (8) may be a conventional teaching method, or the coordinates of the trajectory may be directly set. Other teaching methods such as designated teaching may be used. However, considering the continuity of operation, teaching is performed by the teaching method of the present embodiment up to the component supply position as shown in FIG. Is desirable.

  By memorizing the trajectory for removing the insertion part in this way and teaching the trajectory that moves in the reverse direction as it is, even if it is a fitting insertion with a small clearance, it does not collide near the insertion entrance, and only by position control Can be inserted smoothly. This is considered to be because the operation when removing the inserted part that has already been inserted has no blurring due to the removal.

  Note that when teaching by directly gripping the insertion part by hand, there is a possibility that the teaching may be started from a state where the insertion part has not reached the bottom of the hole (inserted portion). In this case, if the hole (inserted portion) is a cylindrical hole, the height (depth) of the bottom of the hole (inserted portion) is set in advance and the insertion depth of the inserted part is read. Thus, based on these pieces of information, it is possible to detect a displacement between the position of the insertion part and the bottom of the hole (inserted portion). And by extending the trajectory downward from the teaching start position by the amount of deviation of this position (the reverse direction of the pulling operation), even when the inserted part does not reach the bottom of the hole (inserted part), it is more accurate A trajectory can be taught.

(Embodiment 2)
In the second embodiment, when the parallel link robot 10 performs a series of component insertion operations using the component insertion trajectory taught by the teaching method described in the first embodiment, A case will be described in which compliance control is applied so that a hole can be smoothly inserted even when a processing error, an assembly error, a gripping error at the time of chucking, or the like slightly exists in the hole.

  In the present embodiment, as shown in FIG. 7, the compliance control of the parallel link robot 10 is performed by setting an elastic center at the tip, and with reference to the position, the elastic constant and viscosity coefficient in each xyz axial direction, It is defined that the elastic constants and viscosity coefficients for θx, θy, and θz are set for each of the six axes in total.

  The parallel link robot 10 of the present embodiment is provided with a force sensor 20 between the movable plate 13 and the end effector 18, and the compliance control can be performed by setting the position of the elastic center at the center of the tip of the insertion part.

  FIG. 8A and FIG. 8B show typical insertion examples when compliance control is performed.

  FIG. 8A shows a model that is inserted into a hole in a state where an insertion part is held by an end effector 18 provided on the movable plate 13. Here, the center of elasticity in the insertion operation is set to the center of the tip of the insertion part. In this state, the movable plate 13 is brought close to the hole (see (1) “approach” in FIG. 8A). Then, the insertion part comes into contact with the hole, and based on the sensing result of the force sensor 20, along the chamfered part of the insertion part or hole (in this figure, the chamfer of the hole) It is inserted (see (2) “Translation” in FIG. 8A). Once it starts to be inserted into the hole, it is likely to be caught, but since the elastic center is at the tip, it can be inserted without causing the catch (see (3) “Insert” in FIG. 8A). FIG. 8B shows a model when a cylinder is inserted into an insertion part.

  An example in which compliance control is added to a series of component insertion operations of the parallel link robot 10 according to an embodiment of the present invention will be described with reference to the flowcharts of FIGS.

  Since the teaching method is the same as that of the first embodiment, the description is omitted.

  First, as shown in FIG. 9A, with the chuck of the end effector 18 of the movable plate 13 opened, the movable plate 13 is brought close to the insertion part (see S21 in FIG. 10), and shown in FIG. 9B. Similarly, the movable plate 13 is stopped (see S22 in FIG. 10).

  Next, as shown in FIG. 9 (3), the end effector 18 grips the inserted part (see S23 in FIG. 10), and as shown in FIG. 9 (4), the movable plate 13 is moved close to the hole. (See S24 in FIG. 10).

  Next, as shown in FIG. 9 (5), switching to compliance control is started, and the insertion operation, which is the reverse operation of the aforementioned extraction operation, is started with the position of the elastic center being set at the center of the tip of the insertion part. (Refer to S25 in FIG. 10). By performing compliance control at the time of insertion, as shown in FIGS. 9 (6) and (7), even if the position of the hole is shifted, it can be inserted while automatically correcting the insertion operation (see FIG. 9). 10 S26).

  Finally, as shown in FIG. 9 (8), the end effector 18 is removed from the insertion part, and the movable plate 13 is retracted from the hole (see S27 in FIG. 10).

  In this way, by performing compliance control at the time of insertion, in the process of inserting the insertion part into the hole of the member to be inserted, the force sensor 20 detects the force displacement due to the contact of the insertion part with the member to be inserted, and from the target position. The elastic constant and the position of the elastic center can be controlled in accordance with the displacement of.

  In other words, even if there is a processing error, assembly error, gripping error during chucking, etc. in the inserted part or hole, the error is automatically corrected by performing compliance control on the trajectory in the direction opposite to the taught trajectory. Can be inserted. In addition, since it is a compliance control after performing the operation | movement reverse to the locus | trajectory of the teaching teaching of Embodiment 1, precise insertion is possible only by a little chamfering.

(Embodiment 3)
In the third embodiment, when the parallel link robot 10 performs a series of component insertion operations using the component insertion trajectory taught by the teaching method described in the first embodiment, the above-described implementation is performed. The compliance control that does not use the force sensor described in the second embodiment will be described.

  Since the force sensor 20 (see FIG. 9A) converts strain into force, it is vulnerable to impact and easily broken. When this is mounted and operated around the end effector 18 or the movable plate 13, the force sensor 20 may be broken if it collides with the periphery due to some mistake. Therefore, the compliance control without using the force sensor has a simple configuration and excellent durability. FIG. 11 shows a block diagram. The target elastic center is set, viscoelasticity is calculated from the displacement amount and the difference from the set position, and the target generated force is obtained. In order to operate like force control using position control, calculation of position control is next entered. Take the difference of the actual generated force from the target generated force. The actual generated force can be estimated from the current value of the motor 15. As a result, compliance control can be performed without using an expensive force sensor that is weak against impact.

  An example of insertion is the same as in FIG. 9 where the force sensor 20 is not present, and the teaching method is the same as in the first embodiment. The flowchart is also the same as FIG.

  In the embodiment described above, the trajectory of the operation (see FIGS. 3 (3) to 3 (4)) for removing the inserted part previously inserted into the hole from the hole is stored, and the reverse of the stored extraction operation. In the above description, the configuration in which the motion of the orientation is taught as the locus for the component insertion operation corresponds to an example of the teaching method for the component insertion robot of the present invention. However, the present invention is not limited to this. For example, the trajectory of a series of operations from FIG. 3 (3) to FIG. 3 (7) (however, excluding the opening / closing operation of the end effector 18) is stored, and the stored series of operations (extraction operation). 3 (3) is used as a teaching of the first half of a series of component insertion operations (corresponding to the operations of FIGS. 5 (1) to 5 (7)) and stored in FIG. ) To FIG. 3 (6) (except for the opening / closing operation of the end effector 18) in the latter half of the part insertion series of operations (FIG. 5 (8) and subsequent operations). For example, a configuration may be used in which the loci of both are connected smoothly.

  Further, in the above embodiment, in the fitting insertion operation with a small clearance, the locus of the operation for removing the inserted part is stored, and the operation opposite to the stored locus of the removing operation is taught as the part insertion locus. explained. However, for example, in the case of a fit insertion operation with a large clearance, when a blur occurs when the guide is pulled out, a spacer having a thickness corresponding to the clearance between the insert component and the insert member is inserted or inserted to prevent the shake. It is also possible to adopt a configuration in which after a pre-mounting operation is performed, an extraction operation is performed, the locus thereof is stored, and an operation opposite to the stored extraction operation locus is taught as a component insertion locus.

  The present invention can be applied to applications such as teaching precise insertion work, for example, since teaching of robot component insertion operations is easy.

DESCRIPTION OF SYMBOLS 10 Parallel link robot 11 Joint part 12 Fixed plate 13 Movable plate 14 Arm 15 Motor 15a Encoder 17 Link 18 End effector 21 Universal joint

Claims (7)

In a method of teaching a trajectory for inserting an insertion part gripped by an end effector of a robot into an inserted member,
Teach the trajectory of the extraction operation of the inserted part inserted into the inserted member,
Setting a trajectory in the opposite direction to the trajectory of the insertion operation of the inserted component as a trajectory of the component insertion operation;
Teaching method of robot part insertion operation. When the teaching is started from a state where the insertion part is not inserted to the bottom of the insertion portion of the inserted member,
Based on the depth of the bottom of the insertion part and the insertion depth of the insertion part, a deviation between the insertion part and the bottom of the insertion part is detected, and the insertion part is equivalent to the deviation from the position where teaching is started. Extend the trajectory in the opposite direction
The teaching method of the component insertion operation of the robot according to claim 1. A spacer having a thickness corresponding to the clearance between the insertion component and the inserted member is attached in advance to the insertion component or the inserted member to perform the extraction operation.
The teaching method of the part insertion operation | movement of the robot of Claim 1 or 2. The robot is a 6-axis drive parallel link robot that uses a direct drive motor without gears as an electromagnetic motor, and is composed of a movable plate and a fixed plate provided with the end effector.
The teaching method of the part insertion operation | movement of the robot as described in any one of Claims 1 thru | or 3. The component insertion operation of the insertion component is performed using the locus taught by the teaching method of the component insertion operation of the robot according to any one of claims 1 to 4.
How the robot works. The end effector includes a force detection unit capable of detecting a contact force applied to a grasped insertion part,
In the insertion operation of the insertion part using the trajectory, an elastic center based on the contact force detected by the force detection unit is set at the center of the tip of the insertion part.
The robot operation method according to claim 5. In the insertion operation of the insertion part using the locus, the displacement due to the contact of the insertion part with the member to be inserted is detected, and the elastic constant and the position of the elastic center are determined according to the displacement of the displacement from the target position. Control,
The robot operation method according to claim 6.