JPH05237784A - Direct teaching device of articulated robot - Google Patents

Abstract

PURPOSE:To provide the direct teaching device of an articulated robot which can act lightly and stop at a minute position. CONSTITUTION:A force is detected by a force detector 12 installed on the top end part 11a of a robot and the size and its direction of the maximum force worked within a certain period of time after starting the detection of the force by the force detector 12 is calculated by a maximum force calculating part 22 and the distance corresponding to the size of the maximum force is calculated by an action distance calculating part 23 and the robot is controlled so as to move the top end part of the wrist of the articulated robot in the maximum force direction by the distance calculated by the action distance calculating part 23 by a pitch action controller 24. Thereafter, after stopping for a certain time, a pitch action mode by which a minute distance action can be preformed surely can be carried out. This device is constituted so that this pitch action mode can be switched freely to a continuous action mode by which the articulated robot is driven continuously by a speed command corresponding to the detection signal of the detector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct teaching apparatus for teaching articulated robots, which teaches movements to articulated robots.

[0002]

2. Description of the Related Art As a conventional articulated robot teaching method, a teaching person operates a robot operation key of a remote control device connected to a robot controller to guide the articulated robot and store the position. There are a teaching method and a direct teaching method in which an operator grabs and operates the tip end portion of the wrist of the articulated robot to operate and teach.

However, in the case of the above-mentioned remote teaching method, in order to guide the articulated robot to a desired position or posture to operate, the robot operation keys must be operated, so that the operability is poor and skill is required. there were.

Further, in the case of the direct teaching method in which the operator grasps and operates the tip portion of the multi-joint robot, the robot has a multi-joint robot in which the driving source of the joint which does not fall due to gravity is cut off in the old art. Although there is a teaching method of grabbing and operating the tip portion, this teaching method is limited to the case of a joint that does not fall due to gravity, and has a drawback of poor operability.

Recently, a force detector is provided at the tip of an articulated robot, and a signal generated from the force detector, that is, a speed corresponding to the magnitude of the force to the tip is continuously detected,
There is a direct teaching device that continuously drives a driving device of an articulated robot at this speed to perform teaching.

[0006]

However, in the direct teaching device for the articulated robot having the above-mentioned conventional structure, the force signal detected by the force detector changes abruptly. It was difficult to operate it lightly and stop it at a fine position. In other words, when an operator holds the robot tip and teaches directly, if the driving force is increased with respect to the force signal, the robot tip reacts sensitively and oscillates too much. It required a great deal of power to make it move big.

The present invention solves the above problem, and an object of the present invention is to provide a direct teaching method for a multi-joint robot, which enables the robot to move lightly and stop at a fine position.

[0008]

FIG. 2 is a diagram showing the principle configuration of the present invention. As shown in FIG. 2, the articulated robot 1
In the direct teaching device, the force detector 2 that detects the direction and magnitude of the force acting on the wrist tip of the articulated robot 1 is attached to the wrist tip, and the force command detector 3 detects the force detector. The speed command is calculated from the force signal to drive the joint drive motor 1a of the articulated robot 1, and the storage device (not shown) stores the position of the articulated robot. In addition to such conventional functions, the maximum force calculator 4 that calculates the magnitude and direction of the maximum force that has worked within a fixed time after the force detector 2 starts detecting the force.
And a movement distance calculation unit 5 for calculating a minute movement distance according to the magnitude of the maximum force calculated by the maximum force calculation unit 4.
Then, the wrist tip of the articulated robot 1 is controlled to move at a constant speed in the direction of the maximum force by the distance calculated by the movement distance calculating unit 5, and then stopped for a fixed time, and the memory is stored. Articulated robot 1 for the device
And a pitch operation control unit 6 for storing the position of the robot, and continuously sends a speed command according to the force signal detected by the detector, and continuously drives the joint drive motor 1a of the articulated robot by this speed command. A mode selector switch 7 is provided for switching between a continuous operation mode to be performed and a pitch operation mode by the pitch operation controller 6.

Reference numeral 8 is a signal amplifier for amplifying the force detected by the force detector 2, and 9 is a tip for coordinate conversion from the tip coordinate system to each joint system of the robot for operating the position and posture of the robot tip. The joint coordinate conversion units 10 are joint drive amplifiers that drive the joint drive motor 1a according to the joint speed command.

[0010]

In the above structure, the operator has the articulated robot 1
When a force is applied by holding the tip of the force detector 2, the force detector 2 detects this force and its direction.

When the mode changeover switch 7 is in the continuous mode, the output from the force detector 2 in the speed command calculation unit 3 directly passes through the maximum force calculation unit 4, the movement distance calculation unit 5, and the pitch movement control unit 6. , Is continuously input to the tip joint coordinate conversion unit 9, and the articulated robot 1 is driven at a speed and a direction according to the detected force. As a result, the articulated robot can be operated lightly.

On the other hand, in the pitch mode, the output from the force detector 2 is sent to the maximum force calculating unit 4, and the maximum force calculating unit 4 within a fixed time after the force detector 2 starts detecting the force. The magnitude of the maximum force exerted and its direction are calculated. Then, the movement distance calculation unit 5 calculates the distance for moving the tip end portion of the articulated robot 1 from the calculated direction and magnitude of the maximum force, and operates the distance calculated by the pitch movement control unit 6. After the operation command is issued, the articulated robot 1 is stopped for a certain period of time. Here, by setting the distance to be operated to be a minute distance as described above, the tip portion of the articulated robot 1 can be easily stopped at a minute position.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 11 is a teaching playback type multi-joint robot, and a wrist detector 11a of this joint robot 11 is provided with a force detector 12 for detecting the direction and magnitude of the force acting on the wrist tip. ing.
Further, 11b is a grip of the articulated robot 11 to which the force detector 12 is coupled, and 11c is a joint drive motor that drives each joint.

The articulated robot 11 is equipped with a direct teaching device. That is, the force detector 12 of the articulated robot 11 includes a speed command calculation unit via the signal amplifier 13 for amplifying and converting the signal of the force detector 12, the low-pass filter 14, the multiplexer 15, and the A / D converter 16. Is connected to the microprocessor 17, and a mode changeover switch 19 is connected to the microprocessor 17 via the I / O port 18.
The joint drive motor 11c is driven via the joint drive amplifier 20 connected to the microprocessor 17.

The microprocessor 17 includes a mode changeover unit 2 connected to a mode changeover switch 19.
1, a maximum force calculation unit 22 that calculates the magnitude and direction of the maximum force that has worked within a fixed time after the force detector 2 starts detecting the force, and the maximum force calculation unit 22 calculates the maximum force. A movement distance calculation unit 23 that calculates a distance according to the magnitude of force, and controls to move the wrist tip 11a of the articulated robot 11 in the direction of maximum force by the distance calculated by the movement distance calculation unit 23. In addition, a pitch operation control unit 24 that stops the operation for a certain period of time and stores the position of the articulated robot 11 in a storage device (not shown) and a direction and speed command from the force detector 12 side or a pitch operation control unit 24 is used. A tip joint coordinate conversion unit 25 that performs coordinate conversion from each direction and distance command to each joint of the robot is provided. In addition, 26 is a timer and 27 is an operator.

Next, the operation of the articulated robot will be described with reference to FIG. In FIG. 1, when the operator 27 holds the grip portion 11b of the articulated robot 11 and applies a force, the force is applied to the force detector 12 coupled to the grip portion 11b. The force detector 12 normally uses forces (Fx, Fy,
Fz) and the moment (M
x, My, Mz) is used. Force detector 1
Since the output of 2 is small, the signal amplifier 13 amplifies up to a voltage (about 5 to 10 V at maximum) that is easily converted by the A / D converter 16. Further, in order to remove noise from the signal, the cutoff frequency is passed through a low-pass filter 14 of about 100 to 200 Hz. The above six types of signals that have passed through the low pass filter 14 are multiplexed by a multiplexer 15 according to an instruction from the microprocessor 17.
Are converted into a single signal and converted into a digital signal by the A / D converter 16.

The signal set by the mode selector switch 19 enters the mode selector 21 via the I / O port 18. When the mode changeover switch 19 is set to the continuous mode, the signal input from the force detector 12 side to the mode changeover unit 21 is directly transmitted to the tip joint coordinate conversion unit 2.
5, the speed command is continuously output to the joint drive motor 11c, and the articulated robot 11 is driven at a speed and a direction corresponding to the detected force. As a result, the articulated robot 11 is operated lightly.

On the other hand, when the mode changeover switch 19 is set to the pitch mode, the signal from the force detector 12 side is sent to the maximum force calculating section 22, and the maximum force calculating section 22 keeps a constant period (0. 2 to 0.4 seconds), the above-mentioned 6 types of signals (forces in the three-dimensional directions XYZ and moments around each axis in the three-dimensional directions XYZ) are input, and the maximum value during the period is obtained for each signal. The time signal from the timer 26 is used for the time measurement at this time. Then, the movement distance calculation unit 23 determines the distance and the angle at which the position and posture of the articulated robot 11 are moved so that the wrist tip 11a moves in the direction in which the force is exerted, from the magnitudes of the above-mentioned six maximum values. calculate.

The pitch motion control unit 24 issues a motion command to move the wrist tip 11a by the input distance and angle, and then controls the wrist motion to stop for a certain period of time.
The time signal from the timer 26 is also used for the time measurement at this time.

The tip joint coordinate conversion unit 25 performs coordinate conversion from the input motion distance and angle motion commands of the wrist end portion 11a to each joint of the robot (usually called inverse kinematics), and each coordinate. Create a speed command for each joint. The joint drive amplifier 20 drives the joint drive motor 11c according to this speed command.

As described above, in the continuous mode, the position and posture of the wrist tip 11a of the articulated robot 11 can be continuously and lightly operated in the direction in which the force of the force detector 2 is acting. In addition, when the pitch mode is set, the wrist tip 11a is surely subjected to a minute movement (for example, about 2 to 5 mm at maximum depending on the magnitude and direction of the force) from the force applied to the wrist tip 11a for a short time. It can be done.

[0022]

As is apparent from the above description, according to the present invention, a speed command is continuously transmitted in response to a force signal detected by a detector, and the speed command is used to drive the articulated robot. In addition to the continuous operation mode in which the robot is continuously driven, a pitch operation mode that allows the wrist tip to be moved in small steps is provided, and both of these operation modes can be switched. It is possible to operate and give a small instruction, and improve operability.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration and an operation sequence of a direct teaching device for an articulated robot according to an embodiment of the present invention.

FIG. 2 is a diagram showing a principle configuration and an operation sequence of a direct teaching device for an articulated robot of the present invention.

[Explanation of symbols]

 11 multi-joint robot 11a wrist tip 11c joint drive motor 12 force detector 17 microprocessor (speed command calculator) 19 mode changeover switch 22 maximum force calculator 23 working distance calculator 24 pitch motion controller

Claims (1)

[Claims] 1. A force detector for detecting the direction and magnitude of a force acting on this wrist tip is attached to the wrist tip of an articulated robot, and a force command calculation unit detects a force signal detected by the force detector. A teaching playback type multi-joint robot direct teaching device that calculates a speed command to drive a drive source of the multi-joint robot and stores the position of the multi-joint robot in a storage device. A maximum force calculation unit that calculates the magnitude and direction of the maximum force that has worked within a certain time after the start of detection, and an operation that calculates a distance according to the maximum force magnitude calculated by this maximum force calculation unit The distance calculation unit and the movement distance calculation unit are controlled to move the wrist tip of the articulated robot in the direction of maximum force by the distance calculated by the movement distance calculation unit, and then stopped for a certain period of time. A pitch operation control unit that stores the position of the articulated robot in a storage device, and a speed command is continuously sent according to a force signal detected by a detector, and the drive source of the articulated robot is continuously supplied by this speed command. Direct teaching device for an articulated robot, comprising a mode change switch for switching between a continuous operation mode for mechanically driving and a pitch operation mode by the pitch operation control section.