JPS6297005A - Controller for articulated robot - Google Patents

Abstract

PURPOSE:To cope with the change of the working environment and a complicated working object by fetching the environment information or the command of an operator to change automatically the characteristics of an articulated robot control system in a working mode. CONSTITUTION:The angle command signal delivered from a microcomputer is amplified by a servo amplifier and transmitted to a serve valve 13 to control the driving direction and the driving amount of a hydraulic oscillating actuator 10. The action angle of the actuator 10 is detected by an angle detector 12 and always fed back to the servo amplifier. The servo amplifier compares the angle information on the microcomputer with the feedback information given from the detector 12 and delivers the driving signal of the valve 13 in the direction where the deviation between said angle information and feedback information is corrected. When the load conditions and the environmental conditions are decided, a variable feedback mechanism changes the position feedback control to the force feedback control or the speed feedback control.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a control device for an articulated robot, and in particular, when an articulated robot performs an object grasping operation, it is possible to grasp a soft object with less deformation, and to The present invention relates to a control device for an articulated robot (leg mechanism) that is suitable for walking stably without falling over due to uneven floor surfaces when the articulated robot (leg mechanism) walks.

[Background of the invention]

As described in Japanese Patent Application Laid-Open No. 59-18194, the conventional control device, when various types of redemption codes are input to the robot,
Some robots are equipped with a control device that switches the operating mode of the robot from an operating state to an eight state, and vice versa. Also, JP-A-58-47310
Some devices, such as the one described in the above publication, are equipped with a contact detector attached to the gripping part of the robot, and the positioning of the robot is controlled based on the detection signal from the contact detector.

As described above, in the conventional device, even when switching the robot operation mode, the control sequence such as position feedback control is fixed, and only the actual operation of the robot is changed. Therefore, when the robot's task is to palletize soft objects with complex shapes, it is necessary to develop a dedicated gripping device, and there has been no device that takes into consideration the handling of various complex-shaped objects.

[Object of the Invention] An object of the present invention is to enable an articulated robot to respond to changes in the work environment and the increasing complexity of work objects, and to expand the work range of the highly functional articulated robot.

[Summary of the invention]

The present invention relates to a control device for an articulated robot.

By capturing surrounding environment information or operator commands, the characteristics of the control system of the articulated robot can be automatically adjusted during work←
It is designed to function as a completely separate robot before and after the switching and control system switching. That is, it is characterized in that it is equipped with a variable feedback mechanism that switches from one-position feedback control to position feedback control or velocity feedback control in accordance with various detectors or commands from the operator.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described as an articulated biped robot,
The explanation will be given using a manipulator that performs palletizing work of flexible materials as an example.

Figure 1 shows the outline of the foot walking robot. The bipedal walking robot has two axes, waist pitch 1 and waist roll 2, at the position corresponding to the human waist, one axis of wisteria pitch 3 at the knees, and ankle pitch 4 and ankle roll at the ankles. One leg is made up of two axes (5) and one axis (yaw axis 6) for changing direction. Each joint shaft has a hydraulic swing actuator 10 for driving. Furthermore, hydraulic swing actuator]
An angle detector 12 and a servo valve 13, which is a fluid control element that controls the operation of a hydraulic swing actuator, are attached to the shaft of 0 through a coupling 11. Also,
Hydraulic pressure P input to the hydraulic swing actuator 1o
CI and PC2 are detected, and the load acting on the joint is determined from the results (Fig. 2).

The hydraulic power sources 9.9', 9' are further provided with a control device 9 on the waist with a heat insulating material 8 in between.

A flexible piping hose is connected to one joint between the hydraulic power source and the servo valve, and a signal cable is connected to the control device 9, the servo valve 13, and the angle detector 12 by three hoses for supply, return, and drain. is connected. The hydraulic power source is a hydraulic pump motor 9
, a hydraulic tank 9', and accessories such as a relief valve 9', which supply the pressure and flow required to drive the robot. The control device 7 includes a microcomputer that processes information that determines the walking motion of the robot, and a servo amplifier that drives and controls the servo valve 13 that is a fluid control element. A heat insulating material 8 is provided between the hydraulic power source and the control device so that the control device is not affected by the heat generated by the hydraulic pump motor.

Figure 2 shows a control system diagram of a bipedal walking robot. The angle command signal output from the microcomputer is amplified by the servo amplifier and transmitted to the servo valve. The servo valve 13 has the function of adjusting the oil flow rate supplied from the hydraulic power source using a spool built into the servo valve 13 and switching the flow direction of the oil.
Adjust the driving direction and driving amount of o. The operating angle of the hydraulic swing actuator 10 is detected by an angle detector 12,
The angle information is constantly fed back to the servo amplifier, and the servo amplifier compares the angle information from the microcomputer with the feedback information from the angle detector 12.
A signal is output to drive the servo valve in a direction that corrects the deviation. FIG. 3 shows a block diagram of this control system.

According to Figure 3, the output angle θ and the set angle □. Find the difference, differentiate it using differentiator C, and use the result as position control gain A.
It is multiplied proportionally by , and integrated by an integrator circuit. The new output angle θ obtained in this way is outputted to the robot again, and the position feedback control system performs the above-mentioned arithmetic processing and controls the robot.

Here, the walking method of the bipedal walking robot will be explained with reference to FIG.

FIG. 4 is a conceptual diagram of staggered walking, which is one example of robot walking. In Figure 4, the joint J is marked with
The body of the robot is represented by straight lines connecting the joints, and the sole plate 16 is represented by a rectangle.

Walking begins with movement step I, and moves to movement step ■1.
The walking motion of the steps is completed.

First, in operation step (2), the robot stands with its right foot R and its left foot floating backwards. From this state to the state of movement step ■, the left foot swings forward. Therefore, in movement steps I to ■, the right foot R supports the robot's own weight, so a large load is applied to the right foot. However, since the left foot is floating in the air, there is almost no load acting on this left foot. Furthermore, when this movement is performed, the left foot is swung forward, so that the inertia force generated along with the movement of the left foot acts on the right foot R1, particularly the right ankles 4 and 5, as a large load fluctuation.

The next operation steps V to (2) are steps for switching the foot supporting the robot's own weight from the right foot R to the left foot. Therefore, the unevenness of the floor surface acts as a very large disturbance to the stability of the robot, resulting in severe load fluctuations on both ankles 4 and 5.

When such load conditions and surrounding connection conditions are determined,
The above-mentioned position feedback control is optimal at the left end of the operation steps I to (2), where the load is light and positional accuracy is a problem, floating in the air.

Also, the right foot R of movement steps I~■ and movement steps 7~
Both feet R and L between 1 are in order to cope with the influence of the floor surface etc.
Simple position feedback control is insufficient, and position feedback control is optimal. Based on this result, we invented a control system in which the control system can be switched between position feedback control and position feedback control. The control block diagram is shown in FIG.

When the foot is in the air, the feedback control system F is disconnected by the switch E, and the position feedback control system becomes the same as that shown in FIG. 3. Here, when grounding information is input from the grounding sensor 15 to the control device 7, the switch E is operated and the feedback control system F is connected.

As a result, a stable control system can be realized that can operate at high speed when the feet are floating in the air, and can respond to irregularities on the floor when the feet are on the ground, so that the biped walking robot device does not fall over. This has the effect of making you walk more stably.

Next, a manipulator will be explained as a second embodiment.

FIG. 6 is an external view of the manipulator. The manipulator includes a drive control device 17 and a base portion 21 combined. Further, an upper arm portion 22 and a forearm portion 24, 2 are attached to the base portion 21.
5. Wrist parts 26, 27 and grip parts 28, 29 are attached. The drive control device incorporates a drive source 35 and a control device 34, which drives the drive mechanism 18, 19 and rotates the base part 21. Similar drive mechanism 20°2
3. 30 to 32 are assembled to each arm, and each joint is structured to rotate. In addition, 1 gripping part 2
Reference numeral 8 denotes a drive device 33 that drives the gripping portion @29, and includes a detector 36 that detects an external load acting on the gripping device.

Consider the operation of the manipulator during palletizing. Palletizing involves taking boiled eggs out of a pot and arranging them on a desk.

Boiled eggs are very soft and will break if too much force is applied to them, and each boiled egg has a different shape. Therefore, position feedback control is inappropriate for grasping with a manipulator, and it is necessary to perform position feedback control. On the other hand,
Position feedback control is suitable for the positioning operation performed by the gripping section to prevent the egg from rolling after it is placed on the table.

FIG. 7 is a control block diagram corresponding to such control.

If you want to grasp the eggs softly, use the setting grasping force. ′ and the actual grasping force τ′, and use the result as the force control gain B
', differentiating circuit C', and integrating circuit D'.

D' is processed to determine the output angle θ. On the other hand, when performing the egg positioning operation, from the above case, switch E'
, E'' are switched, resulting in a control system corresponding to the control block in FIG.

By applying the present invention as described above, it becomes possible to palletize boiled eggs without breaking them.

According to the embodiments of the present invention, the functions of the conventionally fixed control system can be automatically changed, so that optimal control of the articulated robot can be achieved. It is possible to realize general-purpose use, high-speed control, and stable control, and also to reduce the size and weight of articulated robots, improve durability, and improve economic efficiency.

The above effects will be specifically explained for a biped walking robot device.

In a bipedal walking robot, the control system can be automatically switched between position feedback control and position feedback control based on ground contact information. Therefore, it is possible to perform optimal control that can flexibly respond to surrounding environmental conditions such as unevenness of the floor surface and the influence of the other foot. For this reason, bipedal walking robots can be adapted to various types of floor surfaces (including slopes, etc.), making them highly functional and versatile. In addition, it is possible to walk stably without falling despite the unevenness of the floor surface, so it is possible to increase the walking speed. Furthermore, since optimal control is possible, the actuator can be made smaller and the robot body can also be made smaller and lighter.

As a result, the load acting on each sliding part of the robot is reduced, so the life of each part is extended, which is economical. In addition, the robot can be made smaller and lighter, which has the effect of reducing the amount of materials used.

A similar effect exists for manipulators.

〔Effect of the invention〕

The present invention includes a variable feedback mechanism that switches between position feedback control, torque feedback control, and speed feedback control according to data from a detector or input data from a command device.
This has the effect of making it possible for articulated robots to respond to changes in the work environment and the increasing complexity of work targets, thereby expanding the work range of highly functional articulated robots.

[Brief explanation of drawings]

1 to 5 are diagrams for explaining one embodiment of the present invention, and FIG. 1 is a front view of a bipedal walking robot. Figure 2 is the control system diagram of the bipedal walking robot shown in Figure 1.
The figure is a position feedback control block diagram of the bipedal walking robot shown in Fig. 1, Fig. 4 is a conceptual diagram of walking when the bipedal walking robot shown in Fig. 1 performs staggered walking, and Fig. 5 is a block diagram of the bipedal walking robot shown in Fig. 1. Control block diagrams, FIGS. 6 and 7 are diagrams explaining the second embodiment of the present invention, FIG. 6 is a front external view of the manipulator device, and FIG. 7 is a control block diagram of the manipulator shown in FIG. 6. It is. 1... Hip pitch axis, 2... Waist roll axis, 3... Knee pitch axis, 4... Ankle pitch axis, 5... Ankle roll axis, 6... Direction change yaw axis, 7 ...control device, 8.
...Insulation board, 9...Hydraulic pump/motor, 9'...
Oil tank, 9'...Accumulator, 10...Hydraulic swing actuator, 11...Coupling, 12...
...Potentiometer, 13...Servo valve, 14...
- Oil pressure sensor, 15... Ground sensor, 16... Foot sole plate. 6. , Agent Patent Attorney Katsuma Ogawa --- Early 1st 2nd 5th Term

Claims (1)

[Claims] 1. In an articulated robot equipped with a joint mechanism, a control device, and a load detector, one of position feedback control, force feedback control, and speed feedback control is performed according to data from the load detector. An articulated robot control device characterized by being equipped with a variable feedback mechanism that switches to. 2. An articulated robot equipped with a joint mechanism, a control device, and a contact detector, including a variable feedback mechanism that switches between feedback control, force feedback control, and speed feedback control according to data from the contact detector. A control device for an articulated robot characterized by: 3. An articulated robot equipped with a joint mechanism, a control device, and a proximity detector, including a variable feedback mechanism that switches between position feedback control, velocity feedback control, and force feedback control based on data from the proximity detector. A control device for articulated robots. 4. An articulated robot equipped with a joint mechanism, a control device, and a command device, including a variable feedback mechanism that switches between position feedback control, force feedback control, and speed feedback control according to input data from the command device. A control device for articulated robots.