JPH0253587A - Driving device for robot - Google Patents

Abstract

PURPOSE:To optionally control the power giving a load by providing the control means for controlling the driving power of a driving source by adjusting it according to the reaction force from the load detected by a detection means. CONSTITUTION:The driving of a driving source 13 is transmitted to a load and the transmission means becoming these buffers is provided as well. The reaction force W1 from this load is detected by a detecting means (magnescale) 18 from the buffer operation of the transmission means. The driving force of the driving source 13 is controlled by its increase and decrease by control means 30, 33 according to the reaction force W1 from the load detected by this detection means 18. Consequently, the power given to the load can optionally be controlled by force.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a robot drive device, and more specifically,
This invention relates to simultaneous control of the driving force of the drive device and the reaction force from the load.

[Prior art and its problems] Industrial robot devices are generally equipped with various tools or jigs at the tips of their arms, and are used to perform various tasks. Further, it has been common for the arm to make a predetermined movement, for example, to move a workpiece gripped at the tip of the arm from a certain point to a certain point.

However, in recent years, there has been a demand for moving the arm to a predetermined location on a workpiece or the like and applying a predetermined force to the workpiece or the like there. In other words,
There has been a demand for so-called force control, such as the desire to press a workpiece, etc., with a predetermined constant force or with various forces that can be arbitrarily changed. For example, when a robot device is used to remove the deburr from a cast workpiece, it is necessary to control the force so that the contact force of the deburr tool held at the tip of the arm of the robot device against the workpiece is kept constant.

For such force control, a so-called direct drive structure (DD structure) in which a drive shaft of a motor or the like serving as a drive source directly drives the load side is advantageous.

When force is controlled using the DD structure, a load is always applied to the motor serving as the drive source, which causes problems such as the motor generating heat and becoming high temperature.

On the other hand, AC motors, pulse motors, etc. are unsuitable for the DD structure due to insufficient torque and difficulty in controlling the torque, and the problem is that they cannot perform force control as described above.

Although JP-A-63-7285 discloses an industrial robot having a DD structure, it does not perform so-called force-side control.

[Object of the Invention] The present invention has been made in view of the above-mentioned background, and an object of the present invention is to provide a robot drive device that does not rely on a direct left dry structure and can arbitrarily control the force applied to a load. purpose.

[Structure of the Invention] In order to achieve the above object, the robot drive device according to the present invention is a robot drive device that controls increasing and decreasing the driving force according to the reaction force from the load. A transmission device that is interposed between a drive source and a load, transmits the driving force of the drive source to the load, and acts as a buffer for them.

A detection means for detecting a reaction force from a load from a buffering operation of the transmission means, and a control means for increasing or decreasing the driving force of the drive source, based on the control operation of the control means or the amount detected by the detection means. It is designed so that it can be used.

With the above configuration, the driving force of the drive source is controlled to increase or decrease according to the reaction force from the load detected by the detection means, so that the force applied to the load can be controlled as desired.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a side view schematically showing the main parts of a robot device to which this preferred embodiment of a robot drive device based on the robot rJ1 is applied.

This robot device automatically performs a deburring operation on a cast workpiece A using a deburring tool 2 held at the tip of an arm l. That is, in this robot device, an arm 4 is rotatably supported on a base 3, and the tip of the arm 4 has the other end of the arm 1, that is, the side of the arm 1 that grips the deburring tool 2. The ends are connected. And the robot drive device 10 which is a cylinder type drive source,
Its both ends are connected to a base 3 and an arm 4, respectively.
The robot drive device i! The arm 4 is rotated in conjunction with the expansion and contraction of the arm 210, and the contact force of the deburring tool 2 at the tip of the arm 5 to the workpiece A is controlled to a predetermined force.

Note that the workpiece A is placed a on a fixed table 50, and is transported in a predetermined direction by the fixed table 50 after the deburring operation by the robot device is completed.

FIG. 2 is a partially cutaway side view showing the robot drive device IO of FIG. 1 in enlarged detail. Moreover, FIG. 3 is a cross-sectional view of the robot drive device IO shown in FIG.

The robot drive device IO is a cylinder-type drive source in which an outer cylinder 11 and an inner cylinder 12 are slidably fitted together, and the outer cylinder 11 moves in conjunction with the rotation of a motor 13 that has a built-in speed reducer. Driven to expand and contract.

The motor 13 is fixed to the end face of the inner cylinder 12, and a foot screw 15 extending long inside the inner cylinder 12 is connected to the rotating shaft of the motor 13 on the inner cylinder 12 side.
An encoder 14 is connected to the rotating shaft at the opposite end.

The foot screw 15 is engaged with a piston 16 disposed within the inner cylinder 12. That is, the piston 16 has a ball thread, and the piston 16 is moved in the longitudinal direction of the foot screw 15 in conjunction with the rotation of the foot screw 15. Further, the piston 16 is formed with a pair of opposing four parts 16a, 16a, and the recessed part 1
6a, 16a are slidably fitted into a pair of protrusions 12a, 12a formed on the inner periphery of the inner cylinder 12 to face each other. In addition,
The convex portions 12a, 12a are formed to extend in the longitudinal direction of the inner cylinder 12.

A splinter 17 is provided between the piston 16 and the inner end of the outer cylinder 11, and the outer cylinder 11 is expanded and contracted via the splinter 17 as the piston 16 moves. That is, since the piston 16 is moved as the motor 13 rotates, the movement of the piston 16 causes the outer cylinder 11 to expand and contract via the spring 17.

A Magnescale 18 is provided on the outer periphery of the inner cylinder 2, and a scale rod 19 is slidably fitted into the Magnescale 18. That is, one end of the scale rod 19 is fixed to the outer periphery of the outer cylinder 11 by the support part 20, and the opposite end is fitted into the Magnescale 18. As the outer cylinder 11 expands and contracts, the scale rod 19 moves inside the Magnescale 18. As a result, the amount of expansion and contraction of the outer cylinder 11 is detected by the magnescale 18 .

As described above, in this robot drive device IO, the rotational driving force of the motor 13 becomes the moving force of the piston 6, and the movement of the piston 16 is transmitted to the outer cylinder 11 via the spring 17. The contact force of the deburring tool 2 against the workpiece A due to its own weight is controlled by the piston 16 controlling the expansion and contraction of the spring 17 in its contracted state. That is,
The stretch of the spring 17 is work A of the firming tool 2.
It depends on the contact force, that is, the reaction force from the load, and the outer cylinder 11
When a reaction force is applied from a load to the spring 17, the spring 17 is extended according to the reaction force, and the elongation of the spring 17 is equal to the extension of the outside 011 detected by the Magnescale 18, which is 111 m.
It is calculated from the movement position of the piston 16 detected (calculated) by the encoder 14.

FIG. 4 is a control block diagram of the robot device shown in FIG. 1.

In the same figure, 30 is a CPU, which is equipped with arithmetic units 31 and 32 inside, the arithmetic unit 31 executes force conversion and displacement calculation, and the arithmetic unit 32 executes tonnage balance calculation. do.

The rotation of the motor 13 is controlled by a motor controller 33, and its rotational position, that is, the movement position of the piston 16, is detected by an encoder 14. Then, the position detection value P+ is sent from the encoder 14 to the connection point 34 and the calculation section 32, and the position detection value P1 is mixed and the motor 13 is subjected to so-called feedback control.

The force detection value W1 by the Magnescale 18 is calculated by the calculation unit 31
The calculation unit 31 calculates force conversion and displacement from the force detection value WI, the force command Wj5 and the gravity balance calculation value sent from the calculation unit 32, and sends the results to the connection point 35. It is being sent to In other words, this Magnescale 18° CPU30. The motor 13 is force-controlled by the group of connection points 35 . Note that the position detection value P2 of the other axis is also sent to the calculation unit 32.
A comprehensive sub-coverage balance calculation is performed.

That is, according to such a configuration, the reaction force from the load is detected (
In other words, the spring 17 is calculated from the amount of expansion and contraction of the outer cylinder 11 detected by the magnescale 18 and the movement position of the piston 16 detected by the encoder 1-4.
Since the amount of elongation is calculated, if the motor 13, which is the drive source, is feedback-controlled as shown in Fig. 4 based on the calculation result, the driving force of the motor 13 can be increased or decreased according to the reaction force from the load. The force applied to the load can be controlled by α.

In addition, this robot drive device IO does not rely on the so-called direct trites structure, but instead has a spring 17 between the piston 16 driven and moved by the motor 13 and the outer cylinder 11.
It has a simple configuration in which a spring 17 is inserted, and the force control is performed by utilizing (detecting) the force of the spring 17, that is, its buffering force, so that the heat generated by the motor 13 during cal control is not detected. It is also advantageous in terms of cost.

In the above embodiment, the spring 17 is expanded in response to the reaction force from the load, but is not limited to this.For example, in FIG.
In the case where a2!2 is placed above the arm l, the contact force of the sharpening tool 2 to the workpiece A can be similarly controlled by changing the sharpening tool A2 upward, and in that case, , the sublinter 17 is contracted according to the reaction force from the load.

Further, the robot drive device i10 may be a cylinder-type drive source or a rotary drive type as shown in FIG.

The robot drive device shown in FIG. 5 connects an output shaft 110 and a drive shaft 160 via a winding spring 170, and absorbs the reaction force from the load by the buffering force (spring force) of the winding winding 170. )
The rotational deviation between the output shaft 110 and the drive shaft 160 is detected by the encoder 180 installed at the tip of the drive shaft 160.

In the figure, 120 is a housing, 130 is a motor, i31 is a speed reducer, 140 is an encoder that detects the rotational position of the motor 130, that is, the rotational position of the drive shaft 160, and 190 is the rotational shaft of the encoder 180, which detects the rotational position of the drive shaft 160. The tip of the shaft 190 is fixed to the output shaft 110.

[Effects of the Invention] As explained above, according to the present invention, the driving force of the driving source is controlled to increase or decrease depending on the reaction force from the first stage of detection or the detected load, so the force applied to the load can be controlled arbitrarily. Power can be controlled.

[Brief explanation of the drawing]

Figure m1 is a side view schematically showing the main parts of a robot device to which a preferred embodiment of the robot drive device according to 1 of the present invention is applied, and Figure 2 [J is an enlarged detailed view of the robot drive bag 211O in Figure 1. 311 is a partially cutaway side view shown in FIG.
FIG. 4 shows the control block [A] of the robot device shown in FIG.
, FIG. 5 is a side view schematically showing the main parts of a robot drive device in another embodiment. lO... Robot drive device 13.130... Motor (drive fi) 14.140.
...Encoder (detection-L stage) 17...Spring (
Transmission means) 170-... Winding blade (transmission means) 18... Magnescale (detection means) 180... Encoder (detection means) 30... CPU (control means) 33-... Motor controller (control Means) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A robot drive device that increases or decreases the driving force according to the reaction force from the load, and is interposed between the drive source and the load, transmits the driving force of the drive source to the load, and acts as a buffer for them. A transmission means, a detection means for detecting a reaction force from a load from a buffering operation of the transmission means, and a control means for increasing or decreasing the driving force of the drive source, and the control operation of the control means is controlled by the detection means. A robot drive device characterized by being configured to be based on a detected amount.