JPS59205283A - Industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot used for assembly work and the like.

Conventional industrial robots are based on a teach/reproduce method that faithfully reproduces taught positions and postures, so the servo mechanism that drives each axis is simply one that does not have a position control function. ing. A conventional robot control device of this type is shown in FIG. In the figure, (1) is a command generation unit b (2aX2b) - (21) is a subtracter;
(3a) (3b)-(31) are control elements, (4a) (4
b)... (41) is a power amplifier that drives a servo motor, (5a) - (51) is a DC servo motor, (6
a)-(6i) are speed detectors, (7a)...(71)
is a position detector, (8) is a servo controller, (9) is a robot control device, and (10) is a robot. Note that the subscript i here represents the number of axes constituting the robot.

Next, the operation will be explained. The position command taught in the absolute coordinate system in the work space is divided into two operation commands for each drive axis of the robot in the command generation unit (1), and then sent from the command generation unit (1) to the servo controller (8). for,
Each movement amount per sampling time Xa, Xb,...-
Xt is given. The servo controller (8) includes speed detectors (6a) (6b)...(61) and a position detector (7a) that are directly connected to the output shafts of the servo motors (5a), (5b), and -(5i). (7b)...The speed feedback control system and the position feedback side leg system from (71) are respectively configured, and the robot) (10)
Servo motors (5a) (5b)...(5
1) is stably driven to the target position via power amplifiers (4a), (4b), . . . (41).

Conventional robot control devices are configured as described above, so there is no problem in applications where the robot is moved accurately to a taught position, but it is not a problem in applications such as assembly, deburring of castings, surface polishing of workpieces, etc. For adaptive control applications such as applying a constant force to a target object, or applying a constant force to the surface of a target object, there is a fixed method for controlling the uniqueness of the target object. could not be applied adequately.

(6) This invention was made in order to eliminate the drawbacks of the conventional ones (as described above), and it provides a robot control device with a force control function in addition to the conventional position control function, and each of these functions is By having a function to switch each drive shaft,
It is an object of the present invention to provide an industrial robot that can function both as a conventional position control robot and as the above-mentioned force control robot.

Next, the configuration of the industrial robot of the present invention will be explained.

The industrial robot of the present invention has a robot control device including a speed detector, two position detectors, and a force detector connected to the output shaft of an actuator of the robot, a command generation section, and a servo controller.

The servo controller controls the speed, two positions, and the speed and position output from each of the detectors based on the control mode command output from the command generation unit based on the setting signal input to the command generation unit from the outside.
Position control using force information.

Switching of each force control method is performed for each actuator.

(4) In addition to the position control method and force control method, the robot control device uses the speed 1 position and force information output from the speed detector 1 position detector and the force detector to control external The robot always reacts to the force applied by the robot! I'll lose it 5
It has a switching function between a cover balance control system that operates and an active compliance system that follows the force according to a spring constant set from the outside.

An embodiment of the present invention will be described below with reference to the drawings. , FIG. 2 is a block diagram of an embodiment of the present invention.6 In FIG. 2, (11a) (11b)"-(11i) are force detectors attached to the output shaft of the servo motor; (1)
8j is a command generation unit that generates a position command, and 8j is a servo motor (5a), (5b),
This is a servo controller that controls (51). Based on the data taught in advance, the command generation unit (1) determines whether to control each drive axis of the robot using one of the five control methods provided in the servo controller (8).

Control mode command Ma for each servo motor
g Mb#...v M', position command X&, Xb,
...-, Xi and force commands Pa, F'b, ...
, Fi is output. The servo controller (8) receives the above command and operates the speed detector (6a) (6b) according to each control law.
・(6t), position detector (7a) (7b)・=(7i
) and force detectors (11a) (11b)...(tl
The control law of the command mode is realized using the feedback information of l).

FIG. 3 shows an embodiment of the drive shaft of the servo controller (8). It is assumed that other drive shafts have similar functions as described below.

In Figure 6, (2aH12a) (13a) (15a
) (18a) (20a) are subtractors, (3a) (14a
) (19a) is the control element, (1&) is the position memory, (
17a) (21a) is a switch. The same reference numerals as in FIG. 1 indicate the same configurations. The servo controller shown in FIG. 5 has a one position control mode.

A total of four control modes are available: force control mode, active compliance mode, and coverage mode.

In the case of position control mode, the output of the control element (3a) and the input of the power amplifier (4a) are selectively connected by the switch (24a), and the output of the speed detector (6a) and the position detector IB (7a) are connected. The output PS is input to the Bewer amplifier (4a) and the subtractor (2a) to form a position control law,
Positioning with respect to the commanded position is performed in the same manner as before.

In the case of force control mode, the output of the subtracter (12a) and the input of the power amplifier (4a) are selectively connected by the switch (21a), and the output of the speed detector (6a) and the force detector are connected. The output FS of (11a) is inputted into a power amplifier (4a) and a subtracter (1211), respectively, to form a power suppression law. In this case, the force command Fa given from the command generation unit (1) is compared with the feedback information from the force detector (Iia) by subtraction fB (12a), and the output of the servo motor (5a) is calculated as the force command Fa. It is controlled so that it follows.

Next, in the case of active compliance control mode, the output of the subtracter (15a) and the input of the power amplifier (4a) are selectively connected by the switch (21a),
The output signal of the speed detector (6a), the output signal of the force detector (11a), the output signal island of the FS position detector (7a) are respectively the power amplifier (4a), the subtractor (15a), and the subtracter (
13a)(7)-. Further, the spring constant C set from the command generating section (1) is input to the control element (14a) to set this gain. In this active compliance control mode, is the position command Xa set to zero? Therefore, due to the position and force feedback regulation by the subtractor (13aH15a), it becomes a displacement error signal of the servo motor (5a) caused by the force applied to the robot from the outside, and the servo motor (5a) is It generates a force depending on the set spring constant C and operates to return to its original position.

In the cover balance control mode, the switch (21a) controls the output of the subtracter (20a) and the output of the power amplifier (system).
are selectively connected to the output of the speed detector (6a), the output PS of the position detector (7a), and the output of the force detector (11a).
The output FS of the power amplifier (4a) and the subtracter (
18a).

It is input to a subtracter (20a). There is also a position detector (7a
) is also input to the position memory (16a) via the switch (17a)'l. The control element (19a) has a saturation characteristic, and when the input of the control element (19a) is outside a certain range, the output is clamped, and this (
8) The switch (17a) is turned on at the same time. Therefore, in the case of balance control mode, if the magnitude of the force applied from the outside is less than a certain value, it will be equivalent to active compliance control mode, and the servo motor (5a) will generate a force that returns to the original position. But,
When the input of the control element (19a) exceeds a certain value, the servo motor (5a) operates in a direction to reduce the above-mentioned force in accordance with the externally applied force, and as a result, the robot follows the externally applied force. begins to move.

As described above, according to the present invention, a robot control device is not limited to having only a single control law, that is, a position control law, as in the past, but various control laws can be freely selected for each drive axis. So it's nine so.

In addition to conventional position control, there is also force control that generates a constant force, active compliance control that achieves compliance with externally applied forces, and cabalance control that operates to absorb external forces when applied. can be selected for each drive axis, which has the effect of making it possible to create an industrial robot with a control law suited to the required work simply by switching commands.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a conventional robot control device, FIG. 2 is a block diagram showing a robot control device according to an embodiment of the present invention, and FIG. 6 is a block diagram of one drive axis of a servo controller. be. (1) Command generation unit, (6a) (6b)/(6i) =-
Speed detector, (7a) (7b)-(7i)-position detector, (11a) (11b)-(11i)...force detector,
(21a)...Control mode changeover switch% (8)
... Servo controller, (10) ... Robot. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Attorney Masuo Oiwa Procedural Amendment (Spontaneous) Date of 1929 To the Commissioner of the Japan Patent Office 2 Name of the invention Industrial robot 3 Relationship to the person making the amendment Patent applicant address 2-2 Marunouchi, Chiyoda-ku, Tokyo 3 Name (601) Mitsubishi Electric Corporation Representative Hitoshi Katayama 4, Agent address 2-2-3-5 Marunouchi, Chiyoda-ku, Tokyo
, "Detailed Description of the Invention" column of the specification to be amended. 6. Contents of correction (1) "Bewer amplifier" in the first line of page 7 of the specification shall be corrected to "power amplifier." (2) Correct "1 output signal FS position detector" on page 7, line 19 of the specification to "output signal FS, position detector". (3) Details i! :[Power amplifier (5) on page 8, line 12
Correct month a to [power amplifier (41L) J]. that's all

Claims (2)

[Claims] (1) A speed detector, 2 position detectors, and a force detector connected to the output shaft of the actuator of the robot, and a command generation unit that outputs a control mode command based on a setting signal input from the outside. , a servo controller that uses the speed, position, and force information output from each of the detectors to switch the control methods of position control and force control for each actuator based on the control mode command. An industrial robot characterized by having a robot system (incorporated) device. (2) In addition to the position control method and force control method, the robot system uses the speed 1 position and force information output from the speed detector 9 position detector and force detector to The cabalance system (2) system always operates to eliminate the reaction force of the robot against the force applied by the robot, and the active compliance system follows the force according to the spring constant set from the outside. The industrial robot according to claim 1, characterized in that it is equipped with a quantity type switching device.