JPH05297920A - Controller for robot - Google Patents

Abstract

PURPOSE:To provide a robot controller for which can prevent the robot from being broken owing to misoperation. CONSTITUTION:In a step 33, an operation area table to be used to decide which operation inhibition area the operation point of the robot is in and in a step 34, the decision is made by using the area data in the selected operation area table. Consequently, an optional number of operation inhibition areas of the robot in an optional spatial shape can be provided and the area matching operation environment can be selected among them. Therefore, the best operation inhibition areas can be selected corresponding to the operation environment, so the robot is prevented from being broken owing to misoperation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a robot which limits a movement range of the robot, and more particularly to a control device suitable for a robot controlled by a master-slave system.

[0002]

2. Description of the Related Art The operating range of a robot has never been so wide as to be versatile. However, in actual use, from a safety point of view, there is no choice but to limit it to the minimum necessary range depending on the work situation. For this reason,
Conventionally, there has been known a robot apparatus in which an operation area of the robot is separately set as needed within an operation area of the robot.
It can be found in JP-A-195602 and JP-A-61-273605.

In such a case, generally, the motion area of the robot is set for each joint position or orthogonal position according to the type of manipulator, and this motion area is compared with the target position of the robot. Control. For example, in the technique disclosed in Japanese Patent Laid-Open No. 60-195602, the operating region of the joint shaft is taught, and the angle of the operating region is compared with the angle of the joint shaft. In the technology, the operation area is specified by a plurality of planes specified by coefficients and constants of a plane equation.

[0004]

By the way, in the industrial robot, since the operator can actually operate while seeing the work object, the teaching / playback method is generally adopted. In such a case, Even if the operating area is fixed, it does not pose a problem.

However, for example, when a worker cannot directly teach, such as a robot used in space or a robot for deep sea work, that is, the worker cannot be in the vicinity of the work object or is extremely difficult. In such a case, of course, maintenance of the robot is almost impossible, and therefore damage to the robot due to contact with the work object must be absolutely avoided.

Further, in such a case, the robot is often operated by a master-slave method, and it is necessary to prevent the operator's erroneous operation in advance. It must be adapted to the target and work environment.

However, the above-mentioned prior art does not take into consideration the change of the setting of the operation area for the robot, and there is a problem that the robot cannot be sufficiently satisfied from the viewpoint of preventing damage to the robot. ..

This will be described with reference to FIG.
As shown in FIG. 7A, when the target object (work target object) is located at the position indicated by the solid line, the target object indicated by the solid line becomes an obstacle for the robot. Cannot prevent the robot from being damaged unless the area shown by the solid line is excluded.

Next, if the object is moved from the position indicated by the solid line to the position indicated by the broken line, the object indicated by the solid line in FIG. 7B becomes an obstacle for the robot.
The area in which the robot 1 can safely move is a portion excluding the object shown by the solid line, and therefore, the operation area allowed for the robot changes as the work progresses. However, in the conventional technique, since the operation area of the robot is fixed, it is difficult to sufficiently cope with it.

An object of the present invention is to provide a control device for a robot which can always reliably and reliably prevent damage to the robot in response to a change in the position of a work object when the robot is operated. is there.

[0011]

The above object is to provide prohibited area setting means for setting a plurality of intrusion prohibited areas having an arbitrary space shape in the operable area of the robot body, and to select one of the plurality of intrusion prohibited areas. This is achieved by providing area selection means for selecting an arbitrary number of areas and determination means for matching the position of the robot body with the intrusion prohibited area selected by the area selection means.

[0012]

The above-mentioned means works so that the movement of the robot into the arbitrarily selected invasion prohibited area is automatically prohibited during the operation of the robot. Therefore, since the operation area suitable for the work target and the work environment is set, contact between the robot and the target object due to an erroneous operation by the operator is prevented in advance, and there is no risk of the robot being damaged.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A robot controller according to the present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 2 shows the entire configuration of a robot in one embodiment when the present invention is applied to an articulated robot. In the figure, 1 is a robot main body (manipulator), which is driven by six actuators. Stuff, 2 is the robot controller,
3 is a playback console, which starts playback,
A program unit 4 is used to stop the robot, and is used for teaching the robot and setting the operation area.

FIG. 3 is a block diagram of the robot controller 2. The CPU-A5 controls the operation of the robot body 1 and processes such as a man-machine interface, and monitors the operation of the robot using a selected operation area. It also has a function to do. The CPU-B6 uses the data sent from the CPU-A5 as the servomotor M1 as an actuator.
~ Serves as a servo circuit for driving M6. CPU
-C7 communicates with the playback console 3 and the programming unit 4.

Reference numeral 8 is a RAM-A in which a program describing the processing procedure of the CPU-A5 is stored, and 11 is RAM-B in which a program describing the processing procedure of the CPU-B6 is stored. , 12 are RAM-C, C
A program that describes the processing procedure of the PU-C7 is stored. A ROM 9 stores a processing program for loading the program stored in the auxiliary storage device 10 into the RAM-A 8 at the time of initialization.

Next, the control operation according to this embodiment will be described with reference to the flowchart of FIG.

First, in step 21, the interpolation distance M and the interpolation direction vecM vector are calculated. Here, the interpolation start vector is vecPs, and the interpolation end point vector is vec
Let Pe be the interpolation distance M and the interpolation direction vector vec.
M can be calculated by the following equation (1).

[0018]

[Equation 1]

Next, in step 22, the interpolation end is determined using the interpolation distance M and the interpolation cumulative distance Mc. Now
When the interpolation cycle is Δt (ms) and the interpolation speed is V (mm / ms), the interpolation cumulative distance Mc is expressed by the following equation (2).

[0020]

[Equation 2]

If Mc <M and there is no error, it is determined that the interpolation is not completed, and the process proceeds to step 22. If not, the process proceeds to step 28. When the process proceeds to step 28, the interpolation ending process is performed, and the process ends here.

In step 23, the position of the working point is calculated. If the position of the work point is vecPi, this is
It is expressed by the equation (3).

[0023]

[Equation 3]

Then, in step 24, the position vecPi of the working point is changed to the position A of each joint axis by inverse coordinate transformation.
i (i = 1 to 6) is calculated. Then, in step 25, the position vecPi of the working point and the position A of each joint axis
It is determined whether i is in the operation area. If it is within the operation area, the process proceeds to step 26, where the servo position command is performed using each joint angle Ai, while if it is outside the operation area, the operation proceeds to step 27 to stop the robot.

Therefore, the robot main body 1 can be controlled by performing the processing from step 23 to step 26 until the interpolation is completed or the operation area is outside.

Next, the operation area check processing in step 25 will be described with reference to the flowchart of FIG. First, in step 31, the count value c of the counter is set to 0. Then, in step 32, this count value c
If is equal to or larger than the number n of operation area tables, the process is terminated. If not, the process proceeds to step 33.

Step 33 is a process for judging whether or not to use the operation area table indicated by the count value c. In this embodiment, the operation area definition table as shown in FIG. 6 is used for the judgment. It should be noted that this table serves as a region selection means.

If the c-th data in this operation area definition table is other than 0, the operation area table indicated by the count value c is used to proceed to step 34. If not, the operation proceeds to step 35.

In step 34, it is checked whether the position of the working point and the joint angle are within the operation area. For this check, the position vecPi of the work point, the joint angle Ai of each joint axis, and the motion area table indicated by the counter c are used. FIG. 7 shows an operation area table. It should be noted that this table serves as a prohibited area setting means.

There are n motion area tables, and at the beginning of each table, there is provided data called a motion area type indicating whether the following data is data at an orthogonal position or at a joint position. The determination method differs depending on this operation area type as follows. This is
This is to enable the robot body to be adapted to both the multi-joint type and the Cartesian coordinate type. Therefore, in the embodiment of FIG. 2, the motion area type is the joint type. Become.

In case of joint position For each joint angle Ai (i = 1 to 6) of each joint,
If both of them are between the upper limit value and the lower limit value of the operation area table, it is determined as normal, and if not, it is determined as abnormal.

In the case of the orthogonal position, regarding each of the x, y, and z components of the position vecPi of the working point, if they are between the upper limit value and the lower limit value of the operation area table, it is normal, and if not, it is abnormal. To do. Then, it progresses to step 35 and a counter is incremented here.

The operation area is checked by repeating steps 33 to 35 described above until the value of the counter becomes equal to or larger than the number of operation area tables.

Therefore, according to this embodiment, if the data is set in the motion area definition table according to the motion target or the motion environment, the required robot can be selected from the plurality of motion area tables that are prepared in advance. A table corresponding to the invasion prohibited area is arbitrarily selected only for the necessary types, and the operation of the robot body 1 is automatically prohibited corresponding to the table, and the robot can be sufficiently prevented from being damaged.

Next, another embodiment of the present invention will be described. First, in the above-described embodiment, as is apparent from the flowchart of FIG. 1, the operation area is checked under the sum (or) condition for all the operation prohibited areas selected from the plurality of operation prohibited areas. However, instead of this, the check may be performed under the condition of product (and). That is, according to this embodiment, it is normal only when the position of the working point or the joint angle is between the upper limit value and the lower limit value of all the selected operation region tables, and otherwise it is abnormal. ..

Further, in the above embodiment, the operation area is checked during the interpolation operation, but it may be performed during the manual operation during the teaching operation or during the remote operation. Then, for such an embodiment, step 21, step 22, and step 28 in the flowchart of FIG. 4 may be modified appropriately.

In the above embodiment, the present invention is implemented by software. In this case, however, if the software is abnormal for some reason, it cannot be implemented. Therefore, the present invention may be implemented by hardware or may be used together. In the case of this embodiment, a plurality of mechanical limit switches may be provided on each joint axis of the robot, and any one of these limit switches may be selected and used.

Therefore, according to the above embodiment, the following effects can be expected. (1) Since a plurality of operation area tables are prepared and the operation prohibited area can be checked using any one of them, it is possible to easily obtain an operation area suitable for the work target or the work environment. (2) When the robot goes out of the operation area, the robot automatically stops, so damage to the robot can be prevented. (3) Since the operating area can be checked not only by software but also by hardware, it is possible to deal with the case where an abnormality occurs in the check by software.

[0039]

According to the present invention, since there are a plurality of operation prohibited areas, it is possible to easily select an operation area suitable for a work target and a work environment. Also, since any number can be selected from a plurality of operating areas,
You can check the operation area suitable for the work target and work environment.

When the robot tries to enter the operation prohibited area, the robot is stopped, so that the damage of the robot can be prevented.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation area check process in an embodiment of a robot controller according to the present invention.

FIG. 2 is an overall configuration diagram of a robot system to which an embodiment of the present invention is applied.

FIG. 3 is a block diagram of a control device according to an embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of one embodiment of the present invention.

FIG. 5 is an explanatory diagram of an operation area definition table according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of an operation area table.

FIG. 7 is an explanatory diagram showing a problem of the conventional technique.

[Explanation of symbols]

 1 Robot main body (manipulator) 2 Robot control device 24 Checking operation area

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Sarugaku 7-1, 1-1 Higashi Narashino, Narashino, Chiba Prefecture Hitachi Keiyo Engineering Co., Ltd. (72) Inventor Masaki Sumita 7-1, Higashi Narashino, Narashino, Chiba Prefecture Hitachi Keiyo Engineering Co., Ltd. (72) Inventor Shinichi Takarada 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefectural office Hitachi Information & Communication Division

Claims (3)

[Claims] 1. A prohibition area setting means for setting a plurality of intrusion prohibition areas having an arbitrary space shape in an operable area of a robot body, and an arbitrary number of areas are selected from the plurality of intrusion prohibition areas. Area selection means and determination means for comparing the position of the robot body with the intrusion prohibition area selected by the area selection means are provided to automatically move the robot into the selected intrusion prohibition area during robot operation. A robot controller characterized in that it is configured to be prohibited. 2. The robot controller according to claim 1, wherein the robot body is a multi-joint type manipulator, and the invasion prohibited area is represented by each joint position of the manipulator. .. 3. The robot controller according to claim 1, wherein the robot body is a Cartesian coordinate type manipulator, and the intrusion prohibited area is expressed by a Cartesian coordinate position of the manipulator. ..