JPH0441189A - Control device for articulated manipulator - Google Patents

Abstract

PURPOSE:To enable a highly accurate control difficult to receive the effects of the tare torque of a manipulator itself and friction, by realizing the simultaneous control of position and force for a articulated manipulator with speed as input. CONSTITUTION:The difference in the target values of the positions and forces in each directions of the orthogonal coordinates system provided on an articulated manipulator and the measurement values of actual positions and forces fed from angle sensors 13-15 and a force sensor 16 is found by a subtraction mean 50, the slippage from the target value is calculated and a correction speed for correcting this slippage is found. This correction speed is analyzed by a speed analysis mean 3, converted into the rotation speed of each joint of the manipulator and the articulated manipulator is driven with this rotation speed being fed to actuators 10, 11, 12 as command. Consequently, in the case of the command being 0, speed = 0 namely, respective joints of the manipulator become just as still because of the speed of each joint being command.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a pricking device applied to an articulated manipulator.

<Prior art> An articulated manipulator has a shape similar to a human arm, and has a shoulder joint and an elbow joint. Furthermore, a gripper is provided at the end of this manipulator, and this corresponds to a human hand.

In addition, each joint of such an articulated manipulator is equipped with an angle sensor that detects the rotation angle of the joint, an actuator that drives the joint, and a force sensor that detects the force applied to the hand at the wrist. It is being

As a conventional technique, there is a structure shown in FIG. 2. The object in FIG. 2 is an articulated manipulator to which the torque of each joint is given as a command. below,
Position control will be explained in order. That is, the angle sensor 13
．． The signals 14 and 15 are converted by the angle/position conversion means 7 into positions viewed from the orthogonal coordinate system 4° in the three-dimensional space. The positional deviation between this position and the target position is determined by the subtraction means 50 and inputted to the position control direction selection means 1, and only the positional deviation in the direction in which position control is performed is outputted to the velocity decomposition means 3. The positional deviation is converted into an angular deviation by the velocity decomposition means 3, and this is outputted to the position control means 5. A correction torque for correcting the angular deviation is determined by the position control means 5. On the other hand, regarding force control, the signal of the force sensor 16 is converted by the force conversion means 8 into a force seen from the orthogonal coordinate system 40 in a three-dimensional space. The edge damage difference between this force and the target force is input to the force m one-direction selection means 2, and only the force deviation in the direction in which force control is performed is output to the force/torque conversion means 4. The force/torque conversion means 4 converts the force deviation into a torque deviation, which is output to the torque control means 6. A correction torque for correcting the torque deviation is determined by the torque control means 6.

The sum of torques for correcting these angular deviations and torque deviations is calculated by the addition means 6o, and is sent to the torque input type servo amplifier 19 of each axis, and is sent to the actuator 1 of each joint.
By driving 0.11.12, the position and force are amended simultaneously so that the position or force of the hand coincides with the target position or force.

<Problems to be Solved by the Invention> However, in the above-mentioned position control and force control, the aim is to match the target position and target force, but the actuator of the manipulator is generally accompanied by a decelerator, There is 1g1W1 in which it is difficult to perform highly accurate force control due to the friction of this decelerator.

Furthermore, although the manipulator's own weight torque is applied to each joint, the angle of the joint may similarly deviate from the target value due to this weight torque, which again makes it difficult to perform highly accurate control.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, it is an object of the present invention to provide a control device for an articulated manipulator that performs highly accurate control.

Means for Solving the Problems> The present invention achieves the above-mentioned objects by providing an articulated manipulator that is equipped with an angle sensor at each joint and a force sensor at the wrist. The subtraction means for obtaining the difference between the target value and the actual position measurement value and force measurement value from the angle sensor and the force sensor is provided, and the dividing part means is provided for obtaining a correction speed from the deviation from the target value, and the correction speed is The present invention is characterized in that it includes a speed decomposition means that decomposes the speed to convert it into the rotational speed of each joint, and uses this rotational speed as a command to simultaneously control the force and position of each joint in each direction.

<Operation> A control device is configured for an articulated manipulator in which the command for each joint of the articulated manipulator is changed to a speed, and the rotational speed of each joint is given as a command. The difference between the target value of position and force in each direction of the orthogonal coordinate system provided in , a correction speed for correcting this deviation is determined, this correction speed is decomposed by a speed decomposition means, and converted into a rotational speed of each joint of the manipulator, and the articulated manipulator is driven using this rotational speed as a command.

As a result, since the speed of each joint is a command, if the command is O, the speed=0, that is, each joint of the manipulator remains stationary.

Therefore, even if the manipulator's own weight torque is applied, the angle of the joint will not deviate from the target value due to this weight torque.

Furthermore, since each joint rotates at a minute speed in response to a minute speed command, it is possible to significantly reduce the effects of friction, allowing highly accurate force control.

Example of implementation An embodiment of the present invention will now be described with reference to FIG.

Note that the same parts as in FIG. 2 are given the same reference numerals.

Each joint of the articulated manipulator 20 is provided with an angle sensor 13.14.15 for detecting the rotation angle of the joint and an actuator 10, 11.12 for driving the joint. Further, a force sensor 16 is provided at the wrist to detect the force applied to the hand.

The actuators 10, 11.12 of each joint are connected to a speed input type servo amplifier 9 and driven thereby. That is, the articulated manipulator 20 is driven by speed commands for each joint.

Breathe down, position control, I'll explain to you in order. Angle sensor 13,1
The signals No. 4 and 15 are converted by the angle/position converting means 7 into positions seen from the orthogonal coordinate system 40 in three-dimensional space.

The positional deviation between this position and the target position is determined by the subtraction means 50 and inputted to the position control direction selection means 1, where only the positional deviation in the direction in which position control is to be performed is outputted to the position control means 5. In the position control means 5, a correction speed for correcting the position wheel difference is determined.

On the other hand, regarding force control, the signal from the force sensor 16 is converted by the force converting means 8 into a force seen from an orthogonal coordinate system 40 in a three-dimensional space. The force deviation between this force and the target force is determined by the subtraction means 50 and inputted to the force 1#im direction selection means 2, where only the force deviation in the direction in which force control is performed is outputted to the force control means 30. . In the force control means 30, a correction speed for correcting the force deviation is determined.

The sum of the corrected speeds from the position control means 5 and the force aiaia means 30 is calculated by the adding means 60 and output to the speed decomposition means 3. In the velocity decomposition means 3, the corrected velocity is converted into a corrected angular velocity for each joint. The corrected angular velocity of each axis is sent to the velocity input type servo amplifier 9, which drives the actuators 10, 11, 12 of each joint so that the position or force of the hand matches the target position or target force. position and force are controlled simultaneously.

In this way, the control of each joint is changed to a speed command and the rotational speed is given as a command, so if the speed is 0, it will remain stationary, and even if its own weight torque is applied, the joint angle will change. The joints will not move or shift, and each joint will rotate accordingly even if minute speeds occur due to friction from the decelerator.

<Effects of the Invention> As explained above, according to the present invention, simultaneous control of position and force is achieved for an articulated manipulator that uses speed as input, thereby reducing the influence of the manipulator's own weight torque and friction. This enables highly accurate control that is difficult to control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional example. In the figure, 3 is a speed resolution means, 5 is a position control means, 9 is a speed input servo amplifier, 10, 11, 12 are actuators, 13, 14, 15 are angle sensors, 30 is a force control means, 50 is a subtraction means, 60 is an addition means. Patent applicant Mitsubishi Heavy Industries, Ltd. Agent

Claims (1)

[Claims] In an articulated manipulator equipped with an angle sensor at each joint and a force sensor at the wrist, position target values and force target values in each direction in a Cartesian coordinate system, and actual values from the angle sensor and force sensor are provided. It is equipped with a subtraction means for calculating the difference between the position measurement value and the force measurement value, it is equipped with a control means for obtaining a corrected speed from the deviation from the target value, and it is provided with a velocity decomposition method that performs velocity decomposition to convert this corrected speed into the rotational speed of each joint. 1. A control device for an articulated manipulator, comprising means for simultaneously controlling force and position of each joint in each direction using the rotational speed as a command.