JPH0962322A - Control device and method for multiaxial robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device/method which can facilitate teaching jobs for actions of a multiaxial robot. SOLUTION: A controller is prepared to control a multiaxial robot based on the target movement position that is previously set. The controller reads the target movement position (S1) and a right-hand inhibition area (S2) out of a RAM when a movement command is executed. Then the target movement position is compared with the right-hand inhibition area (S3). If the target movement position is included in the right-hand inhibition area, the target movement position is shifted to a left-hand inhibition area (S4) and the turnover amount of every rotate joint of the robot is calculated in a left-hand system (S5). If the target movement position is excluded out of the right-hand inhibition area, the target movement position is shifted to the right-hand inhibition area (S6). Then the turnover extent of every rotate joint of the robot is calculated in a right-hand system (S7). Based on these calculation results, the positioning action of the robot is started (S8).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device and a control method for controlling a multi-axis robot.

[0002]

2. Description of the Related Art In order to make a multi-axis robot work,
Generally, the operation program of the robot is created in advance,
It is stored in a storage device inside or outside the control device. The operation program is composed of position information of the work point and an operation program written by various command words called a robot language.

When the multi-axis robot is made to perform a reproducing operation by automatic operation, first, the position information of the working point is stored in the storage device by the teaching work by the teaching device.

Next, the operation program stored in the storage device takes out the instruction words one by one and performs a predetermined operation while decoding the instruction words. When executing an operation command for performing a certain work among these operation commands, the multi-axis robot moves to the designated position by referring to the content of the position information of the work point. Generally, position information of a working point is taught by a worker as a position of a hand provided on a multi-axis robot, and the hand position is expressed in Cartesian coordinates so that the worker can intuitively understand ( For example, "P1 (X0, Y0, Z0, S
0) ”, where S0 is the rotation angle of the hand axis with respect to the Cartesian coordinate system.) Therefore, when the hand position is represented by Cartesian coordinates, the motor stop position of each joint of the multi-axis robot is unique. Is not decided, that is, the multi-axis robot
With respect to one hand position, there are two stop positions of the motor of each joint, that is, the right hand system and the left hand system. There are two methods for uniquely determining this during the teaching reproduction in the automatic operation of the multi-axis robot.

[0005] 1. In teaching work, as hand position information,
Pn (Xn, Yn, Zn, Sn) (n is a work point number) is taught, and when the teaching position is reproduced by the command word of the operation program, there are two left and right motor stop positions for each joint in the operation program. How to select information.

FIG. 6 is a diagram showing an operation program example 1 as a conventional example.

FIG. 9 is a diagram showing hand position information as a conventional example.

As shown in FIG. 6, in LNO2, of the two left and right motor stop positions of each joint of the multi-axis robot, when those motors reach the stop position, the posture of the arm of the multi-axis robot is changed. Set the conditions so that the stop position of each motor is calculated so that is a right-handed system. Then L
In NO3, the stop position of each motor is calculated in a state where the relationship of each joint is a right-handed system. Further, FIG. 7 shows LNO2 and LNO of FIG.
3 is an example in which 3 is combined into one instruction.

FIG. 7 is a diagram showing an operation program example 2 as a conventional example.

[0010] 2. At the time of teaching work, the hand position information is taught in the form of Pn (Xn, Yn, Zn, Sn, ARMn), and the posture element "ARMn" in the hand position information is taken into consideration when the taught position is reproduced. To calculate the stop position of each motor of each joint.

FIG. 8 is a diagram showing an operation program example 3 as a conventional example.

FIG. 10 is a diagram showing hand position information as a conventional example.

As shown in FIG. 10, during teaching work, "RIGHT" or "LE" indicating a right-handed system or a left-handed system is shown as position information on the Cartesian coordinate system as hand position information and posture information.
FT "is set. When the teaching position is reproduced by executing the operation program example 3, the posture information is considered in addition to the position information (LNO2), and the stop position of the motor of each joint is set so that the hand moves to the teaching position. calculate.

[0014]

The above-mentioned case 1 is disadvantageous when the positioning accuracy during reproduction is required. For example, since the posture information at the time of teaching is not left, if the posture opposite to the posture at the time of teaching is instructed in the operation program, the lost motion of the deceleration mechanism of each joint, that is, the movement to the taught position At this time, positioning cannot be performed with high accuracy due to a positioning operation error due to mechanical factors in the robot's right-handed or left-handed operation. As a result, it is expected that the hand attached to the hand position of the multi-axis robot cannot hold the work. In the case of 2, since the element of the teaching position includes the posture when the multi-axis robot is positioned at the teaching position, when the operator performs the teaching work, the teaching position is reproduced for each teaching position. Since it is necessary to set the position accurately while considering the posture of the time, the teaching operator must be skilled in teaching the multi-axis robot. As a specific example, the teaching work was performed with the right-handed system on the same pallet at first, but there is an area where the next position cannot be taught with the right-handed system, so change to the left-handed system. Therefore, it becomes necessary to continue the teaching work, and teaching position data in which the left and right hand systems are mixed is completed on the same pallet. In this state, if the teaching position is reproduced by automatic operation, an extra tact for changing the hand system occurs on the same pallet. In order to prevent this, the teaching work must be redone from the beginning in a left-handed posture, which puts a great burden on the operator.

Therefore, an object of the present invention is to provide a control device and a control method for facilitating the work of teaching the operation of a multi-axis robot.

[0016]

As a constitution of the present invention for solving the above-mentioned problems, a first aspect of the present invention is a control device for controlling a multi-axis robot in accordance with a preset target movement position. A means for presetting an area for limiting the posture during operation, and whether or not the trajectory plan is included in the area for limiting the posture when creating the trajectory plan of the multi-axis robot according to the target movement position. And a means for determining the movement amount of each axis of the multi-axis robot corresponding to the target movement position according to the determined result and the trajectory plan. It is a control device.

This makes it possible to set the individual teaching positions and the limitation of the movement posture during reproduction independently.

According to a second aspect of the present invention, the means for correcting the amount of movement of each axis of the multi-axis robot includes a change of a right-handed system or a left-handed system in which each axis of the multi-axis robot can assume. The control device for a multi-axis robot according to claim 1.

Thus, the multi-axis robot can be operated while avoiding obstacles during operation. Also, the change of hand system,
This is performed only when the multi-axis robot moves in and out of the area where the posture is restricted.

According to a third aspect of the present invention, the means for setting the area in which the posture is restricted is performed by an external device connected to the control device via a communication means. It is a control device.

As a result, the parameter setting at the site level independent of the operation program of the multi-axis robot is realized.

According to a fourth aspect, the area for limiting the posture is
The control device for a multi-axis robot according to claim 2, wherein a plurality of settings can be made.

Thus, a control device for a multi-axis robot can be obtained which can be applied even when the physical constraints of the robot arm and the work are different at the two positions of the movement start position and movement end position.

According to a fifth aspect of the present invention, during the inching operation of the multi-axis robot, the inching operation is stopped when the multi-axis robot touches a boundary of a region that limits the posture. Multi-axis robot controller.

With this, during the inching operation of the multi-axis robot, it is prevented that the hand system whose use is restricted inadvertently enters and leaves the area where the posture is restricted.

As another configuration of the present invention for solving the same problem, a sixth aspect of the present invention is a control method for controlling a multi-axis robot according to a preset target movement position, wherein the multi-axis robot is operated in the following manner. An area for limiting the posture is set in advance, and when the trajectory plan of the multi-axis robot is created according to the target movement position, the trajectory plan is determined whether or not it is included in the area for limiting the posture. A method of controlling a multi-axis robot, comprising: correcting the amount of movement of each axis of the multi-axis robot corresponding to the target movement position according to the determined result and the trajectory plan.

Thus, the setting of each teaching position and the limitation of the operation posture during reproduction can be set independently.

According to a seventh aspect of the present invention, the method of correcting the movement amount of each axis of the multi-axis robot includes changing the right-handed system or the left-handed system which is the posture that each axis of the multi-axis robot can take. The method for controlling a multi-axis robot according to claim 6.

Thus, the multi-axis robot can be operated while avoiding obstacles during operation. Also, the change of hand system,
This is performed only when the multi-axis robot moves in and out of the area where the posture is restricted.

According to the eighth aspect, the area for limiting the posture is
The control method for a multi-axis robot according to claim 7, wherein a plurality of settings can be made.

Thus, a control apparatus for a multi-axis robot can be obtained which can be applied even when the physical constraints of the robot arm and the work are different at the two positions of the movement start position and movement end position.

A ninth aspect of the present invention is characterized in that, during the inching operation of the multi-axis robot, the inching operation is stopped when the multi-axis robot touches a boundary of a region that limits the posture. Is a control method of the multi-axis robot.

With this, during the inching operation of the multi-axis robot, it is prevented that the hand system whose use is restricted inadvertently goes in and out of the area where the posture is restricted.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a system configuration diagram of a multi-axis robot to which the present invention is applied.

In the figure, 4 is a robot controller for controlling the system of the present multi-axis robot, which controls the multi-axis robot for individually moving a plurality of works 29 placed on the pallet 28 to the conveyor 30. This multi-axis robot 11
The first shaft (22), the second shaft (24), and the S shaft (2
6) and the arm 1 (23) that operates using them as a starting point,
Arm 2 (25) and finger (27) are provided. 1 is a teaching device as a man-machine interface.

FIG. 2 is a block diagram of a multi-axis robot to which the present invention is applied.

In the figure, the teaching apparatus 1 is provided with an input unit 2 for inputting various parameters and teaching positions for motions, and a display unit 3 for displaying input values and results. Reference numeral 4 denotes a robot control device, which is a communication interface 5 for exchanging data with the teaching device 1, a CPU for deciphering a movement command or the like from the teaching device 1, servo control, trajectory planning calculation, and the like.
6, a ROM 7 that stores a control program for operating the CPU, a trajectory planning calculation algorithm, etc., a servo gain, a maximum rotation speed of the electric motor, servo parameters such as a rotation direction, and a parameter that determines the type of the coordinate system,
A RAM in which the lengths of the first and second arms of the multi-axis robot 11, the maximum and minimum values of the amount of rotation of each joint, and the left-handed control area are stored as arm solution parameters.
8, a bus 9 for data communication of each element inside the robot controller 4, and a servo system interface 10 having a servo driver. The multi-axis robot 11
It is connected to the robot controller 4 and operates according to the instructions.

First, in the present embodiment, the posture element (the above-mentioned conventional examples FIGS. 6 to 10) input from the teaching device 1 (or the robot control device 4) at the time of setting the motion program or the hand position information. When the position is taught without setting, an area for restricting the movement posture is set within the entire movement area of the multi-axis robot 11. Robot controller 4
When the robot is operated in accordance with the taught position, it determines whether or not each taught position is within a preset region that limits the movement posture of the robot arm, and executes the operation. The explanation is given below based on this idea.

The operation of the servo system interface 10 will be described with reference to FIGS.

FIG. 3 is a flow chart of processing of a movement command command as an embodiment of the present invention.

In the figure, the servo system interface 10 decodes the command transmitted from the CPU 6 via the bus 9, and if it is a movement command command, step S
The target movement position is read in 1 and the right hand system prohibited area in the arm solution parameter is read from the RAM 8 in step S2. Next, in step S3, the read target movement position is compared with the right hand system prohibited area, and if the target movement position is within the right hand system prohibited area, the target movement position is changed to the left hand system (step S4), and in step S5. Multi-axis robot 1
The joint rotation amount of 1 is calculated by the left-handed system. On the other hand, if the target movement position is outside the right-handed system prohibited area, the target movement position is changed to the right-handed system (step S6), and the joint rotation amount of the multi-axis robot 11 is calculated by the right-handed system in step S7. Then, based on the calculation result, the robot 11
Start the positioning operation of.

FIG. 4 is a diagram showing an operation area of the robot 11 as an embodiment of the present invention.

In the figure, the movable area 40 of the multi-axis robot has a structure in which both the right hand system and the left hand system can be taken at the same position, and the area where only one of the right hand system and the left hand system can be taken. Exists above. Here, in order to simplify the explanation, the basic operation of the multi-axis robot 11 is a right-handed system. Next, the method of setting the right-handed system prohibited area 43 in this right-handed system area is as follows.
Point, that is, 44 first area setting position (X1, Y1)
And 45 second area setting positions (X2, Y2). Further, a region 41 that can be physically taken only by the left-handed system is detected by utilizing the rotation angle of the motor, and the other region is a right-handed region 42. If the target movement position is (X,
(Y, Z), the target movement position is determined to be the right hand system prohibited area 43 only when the X coordinate is between X1 and X2 and the Y coordinate is between Y1 and Y2. This applies not only to the PTP (POINT TO POINT) operation during automatic operation of the SCARA type robot, but also to the inching operation during teaching work.

In the case of inching operation, an inching command is sent to the robot controller 4 by operating the key of the teaching device 1. When the robot controller 4 receives the inching command,
The hand position of the multi-axis robot 11 is calculated for each predetermined sampling time, it is determined whether the hand position is included in the left or right restricted area, and the current hand position and the hand position after the next sampling time are controlled to be the same. Only if included in the region,
The multi-axis robot 11 is operated so as to reach the hand position. That is, when the hand position is in the right-handed system region 42, the inching operation moves on the orthogonal coordinate system while maintaining the posture of the right-handed system.

When it is determined that the movement position of the hand after the next sampling time is included in the right hand system prohibited area 43, the inching operation is stopped and the multi-axis robot 11 keeps the right hand system posture and the right hand system. It does not enter the prohibited area 43. If it is desired to continue the inching operation in the right hand system prohibited area 43, the posture of the multi-axis robot 11 is changed to the left hand system. Similarly, the right-handed prohibited area 43
When it is determined that the hand position after the next sampling time is included in the right hand system area 42 during the inching operation in the inside, the inching operation is stopped, and the left hand system posture is maintained and the right hand system is maintained. It does not enter the area 42. If it is desired to perform the inching operation in the right-handed system area 42, the posture is changed to the right-handed system and then performed. When the hand position, which is the teaching position, is reached during the inching operation, the inching operation is stopped and the currently stopped hand position is stored in the robot controller 4 as the target teaching position.

FIG. 5 is a top view of a multi-axis robot system to which the present invention is applied.

(1) When teaching the position of the work When teaching all the positions of the work 29 at the location of (A) (the work 29 exists in several stages on the pallet 28), the multi-axis is taught. The robot 11 must be taught in a left-handed state. This is because the multi-axis robot 11 applied to the present embodiment moves the work 29 at the location (A) from the upper stage to the lower stage in the right-handed system because the movement on the Z-axis operates along the support as shown in FIG. If you try to teach with, the work 2 with the whole arm piled up except the place of (A)
This is because it interferes with 9. That is, when the Z axis is lowered, the arm 1 and the arm 2 are simultaneously lowered. In order to avoid such a situation, the area on the pallet 28 is set in advance as a left-handed area so that the operator cannot perform teaching work such as inching with the right-handed area.

(2) In the case of PTP operation When there is a PTP operation command on the operation program, first, this position is the right hand system area 42 or the right hand system prohibition area 43 according to the X, Y and Z coordinate components of the target movement position. Is determined, and the stop position (= rotation amount) of each motor of each joint is calculated so that the hand system of the multi-axis robot 11 has a posture that is restricted in advance, and the calculated position of each motor is calculated. Drive to become. <Effects of Embodiment> (1) When the hand portion of the multi-axis robot 11 moves to the next target movement position during the playback operation of the teaching position, the arm is provided except when the preset right hand system prohibited area 43 enters and leaves. The attitude of is unified. As a result, the mechanical loss of the deceleration mechanism of the left and right joints, that is, when the position is reached with the left-handed system and the position with the right-handed system at the same teaching position, It is possible to avoid the phenomenon that the position is different to the minimum necessary,
Highly accurate positioning is realized without considering lost motion. (2) Since the worker sets the posture restriction information of the arm in advance as a region, it can be released from the fact that the worker is always aware of the posture of the arm when teaching the target operation position. (3) The right hand system prohibited area 43 is set by setting the first area setting position (X1, Y1) and the 45 second area setting position (X2, Y).
Since it is specified by 2 points of 2), the area of the shape most suitable for the work form can be specified. It should be noted that this restricted area may be configured so that a plurality of restricted areas can be set as necessary. (4) Since the worker sets the arm posture restriction information as a region in advance, a simple configuration in which the arm posture information is deleted from the operation program created by the worker and the teaching position data can be realized (that is, The operation program has the configuration shown in FIG. 8 and the teaching position data has the configuration shown in FIG. 9, and the posture information of the arm can be deleted from either of them.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device as in this embodiment. Further, it goes without saying that the present invention can be applied to the case where it is implemented by supplying a program to a system or an apparatus. In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program from the storage medium to the system or device, the system or device operates in a predetermined manner.

[0051]

As described above, according to the present invention, by setting the posture restriction information of the arm of the multi-axis robot as the area in advance, the burden on the operator who teaches the operation of the multi-axis robot is reduced, It is possible to provide a control device and a control method thereof that facilitate the work.

[0052]

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a multi-axis robot to which the present invention is applied.

FIG. 2 is a block configuration diagram of a multi-axis robot to which the present invention is applied.

FIG. 3 is a flowchart of processing of a movement command command according to an embodiment of the present invention.

FIG. 4 is a diagram showing an operation area of the robot 11 as one embodiment of the present invention.

FIG. 5 is a diagram of a multi-axis robot system to which the present invention is applied, viewed from above.

FIG. 6 is a diagram showing an operation program example 1 as a conventional example.

FIG. 7 is a diagram showing an operation program example 2 as a conventional example.

FIG. 8 is a diagram showing an operation program example 3 as a conventional example.

FIG. 9 is a diagram showing hand position information as a conventional example.

FIG. 10 is a diagram showing hand position information as a conventional example.

[Explanation of symbols]

 1 Teaching device 2 Input part 3 Display part 4 Robot control device 5 Communication interface 6 CPU 7 ROM 8 RAM 9 Bus 10 Servo system interface 11 Multi-axis robot 21 Strut 22 First axis 23 Arm 1 24 Second axis 25 Arm 2 26 S Axis 27 Finger 28 Pallet 29 Work 30 Conveyor 40 Multi-axis robot movable area 41 Area that can be taken only by left hand system 42 Right hand system area 43 Right hand system prohibited area 44 First area setting position 45 Second area setting position

Claims (9)

[Claims] 1. A control device for controlling a multi-axis robot according to a preset target movement position, wherein a unit for presetting an area for limiting a posture when the multi-axis robot operates, and a unit for presetting the region according to the target movement position. When creating a trajectory plan of a multi-axis robot, a means for determining whether or not the trajectory plan is included in the area for limiting the posture, and the target movement position to the target movement position according to the determined result and the trajectory plan. A control device for a multi-axis robot comprising means for correcting the amount of movement of each axis of the corresponding multi-axis robot. 2. The means for correcting the movement amount of each axis of the multi-axis robot includes a change of a right-handed system or a left-handed system which is a posture that each axis of the multi-axis robot can assume. 1. The control device for a multi-axis robot according to 1. 3. The control device for a multi-axis robot according to claim 2, wherein the means for setting the area for limiting the posture is performed by an external device connected to the control device via a communication means. 4. The control device for a multi-axis robot according to claim 2, wherein a plurality of regions for limiting the posture can be set. 5. The multi-axis robot according to claim 2, wherein when the multi-axis robot collides with a boundary of a region where the posture is restricted during the inching motion of the multi-axis robot, the inching motion is stopped. Robot controller. 6. A control method for controlling a multi-axis robot according to a preset target movement position, wherein a region for limiting a posture is preset when the multi-axis robot operates, and the multi-axis robot is controlled according to the target movement position. When creating the trajectory plan of the robot, it is determined whether or not the trajectory plan is included in the area for limiting the posture, and the multi-path corresponding to the target movement position is determined according to the determined result and the trajectory plan. A method for controlling a multi-axis robot, characterized in that the amount of movement of each axis of a multi-axis robot is corrected. 7. The method for correcting the amount of movement of each axis of the multi-axis robot includes changing a right-handed system or a left-handed system, which is a posture that each axis of the multi-axis robot can take. 6. The control method for a multi-axis robot according to 6. 8. The method of controlling a multi-axis robot according to claim 7, wherein a plurality of regions for limiting the posture can be set. 9. The multi-axis robot according to claim 7, wherein when the multi-axis robot collides with a boundary of a region in which the posture is restricted during the inching motion of the multi-axis robot, the inching motion is stopped. Robot control method.