JPH02279285A - Method and device for controlling master/slave manipulator - Google Patents

Abstract

PURPOSE:To bestow a force sense on a master arm without exerting a servolock on the master arm and to increase safety by driving a slave arm with the displacement amount of the master arm as the moving speed information of the slave arm. CONSTITUTION:Based on the signal transmitted from a position detecting means 6 provided on a master arm 1, a speed signal corresponding to the displacement amount of the master arm 1 is formed by a converting means 12. This speed signal is made the driving signal of a slave arm 2, input to the motor driving part 13 of the slave arm 2 and this slave arm 2 is driven and controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a control method and apparatus for a master/slave manipulator.

(Prior art) A general control method for a master/slave manipulator is to spatially connect a master arm with a similar shape to the slave arm, and then adjust the position of the slave arm by a constant times the position of the master arm, and then the slave arm. There is one that makes the force applied to the master arm equal to a constant times the applied force. With this kind of controlled master-slave manipulator, the operator does not have difficulty in positioning the slave arm, and the reaction force is fed back, so the manipulator can easily perform detailed operations.

However, for example, if you want to move the slave arm a lot or use a slave arm that is larger and longer than the master arm, the operating area of the master arm will be smaller than the operating area of the slave arm, making it difficult to respond adequately. In this case, the master arm is electrically fixed with a servo lock, and a speed change is applied to the slave arm joints in proportion to the force applied by the operator to the master arm joints. A method of manipulating the arm was used. This method is called the speed command type, and according to this method, when the operator applies force to the master arm, the slave arm continues to move in that direction. Also, if a large force is applied to the master arm, the movement speed of the slave arm will also increase.

On the other hand, if a small force is applied to the master arm, the movement speed of the slave arm will also be small.

However, conventional speed command type master/slave manipulators have a drawback in that the force acting on the slave arm is not fed back to the master arm because the master arm is servo-locked. Therefore, even if the slave arm collides with an object, it continues to move, and in some cases, the slave arm may be damaged.

(Problems to be Solved by the Invention) As described above, in the conventional speed command type master/slave manipulator, the master arm is servo-locked, so the force acting on the slave arm is not fed back to the master arm. The present invention solves these conventional drawbacks and provides a control method and device for a speed command type master/slave manipulator that improves safety by imparting force sensation to the master arm. purpose.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the force acting on the slave arm is fed back to the master arm, and the displacement amount of the master arm is used as movement speed information of the slave arm. This is the control method for driving the arm. In addition, in order to obtain a drive signal for the master arm, a position detection means is provided on the master arm, and a speed signal corresponding to the displacement amount of the master arm is generated based on the signal from the position detection means, and a speed signal is generated in accordance with the displacement amount of the master arm. The control device has displacement/velocity signal conversion means.

(Function) As described above, if the displacement amount of the master arm is used as the speed command value of the slave arm, there is no need to apply a servo lock to the master arm, and moreover, it is possible to impart a sense of force to the master arm. Therefore.

It becomes a speed command type master/slave manipulator with improved safety.

(Example) The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a control device for a master/slave manipulator according to the present invention. Note that only one degree of freedom each of the master arm and slave arm of the same structure is shown here. A master arm 1 operated by an operator and a slave arm 2 that performs work in conjunction with the master arm 1 each have a multi-degree-of-freedom configuration with a plurality of joints, and are spatially connected. As shown in the figure, one degree of freedom of this joint is determined by a torque detector 3, which is a force detection means.
4, position detectors 5 and 6 degrees as position detection means, and a motor 7.8 as drive means. When the operator applies an appropriate force to the master arm 1, the force Tm is detected by the torque detector 3. On the other hand, when the slave arm 2 acts on an object, the force rs received from the object is detected by the torque detector 4, and multiplied by an appropriate force feedback rate to the master arm 2 by the amplifier 9. These forces JTm
, Ts are compared by a comparator 10 to generate force information T1 that is input to an adder 11 as a force command value.

On the other hand, the axial position 01 of the joint caused by the operator's operation of the master arm 1 is detected by the position detector 5. This signal is manually input to the controller 12, which is a displacement/velocity signal conversion means, and the signal of the shaft position θ is immediately transmitted to the slave arm 2, which performs dead band processing and displacement control to prevent abnormal vibrations from occurring. → Signal conversion to speed and multiplication by amplification factor are performed.

The generated drive signal is inputted to the motor drive section 13 as a speed command value, and drives the motor 8.

Note that although the slave arm 2 is equipped with the position detector 6 here, it is of course possible that the slave arm 2 is not equipped with the position detector 6.

The signal conversion from displacement to velocity in the controller 12 will be further described. First, a predetermined axial position θ1 of the master arm 1 is set in advance as a reference position during operation using a manipulator. Based on the current axis position θ determined by the position detector 5, the controller 12 determines the amount of displacement (θ, -〇,).
is calculated. This detects how much the master arm 1 has displaced from the reference position, and then this displacement amount (θ).

0m) and the output speed signal V, which correspondence is taken? For example, as shown in Fig. 4, even if the output speed signal vll with respect to the displacement (θ, -〇,) is linear, or it changes logarithmically. The speed command value to the jetter drive unit 13 is generated so that it can be freely set in consideration of the content of the work performed by the manipulator, the ease of operation by the operator, and the like.

With this embodiment, even if it is a speed command type master/slave manipulator, the force applied to the slave is fed back to the master arm, so the possibility of damage to the slave arm is extremely reduced and safety is improved. Much improved. Of course, the same effect can be obtained by using a joystick lever or other control device as the master arm.

In addition, in this embodiment, the axial position θ of the joint of the master arm 1,
constitutes a loop so as to be fed back to the master arm 1 itself. This is to generate a restoring force corresponding to the displacement amount of the axial position of the joint of the master arm 1. Now, for example, F [kgf = K [kgf
/mkoXz[mko-Q), let K be a predetermined value,
A restoring force F proportional to I from the reference position is generated, and the larger the operator moves the master arm 1 from the reference position, the greater the braking is applied. Therefore, even if the operator takes his hand off master arm 1,
Since the master arm 1 attempts to return to its reference position, there is no danger that the slave arm 2 will move in the direction it was being operated.

In the restoring force generator 14, which is a displacement/force signal conversion means, a predetermined shaft position θ is set in advance in the same manner as the controller 12, and the displacement amount (era, -o
Calculate ea). Then, this value is replaced with the force in equation (2) to generate the restoring force F, which is used as force information T2 to the adder 11. Here, the axis position θ1 in the restoring force generator 14 is determined by the controller 1.
It is desirable that the same value as the value in 2 be arbitrarily set. Of course, in the above formula (■), K may be a constant or a function of the force as shown in Figure 5, and the restoring force may be generated by a relational expression other than 2 It's okay. ``It is desirable that these settings can be freely set in consideration of the content of work performed by the manipulator, ease of operation by the operator, etc.

The force information T□ obtained as described above is added to the force information T1 obtained from the torque detectors 3 and 4 in the adder 11. The output is then input as a force command value to the motor drive section 15 to drive the motor 7.

In this way, the further the operator moves the master arm 1 from the reference position, the greater the braking will be applied, but when an external force is applied to the slave arm 2, a reaction force in that direction will suddenly be applied to the master arm. 1, so the operator can easily distinguish between the restoring force and the external force.

It becomes a master/slave manipulator that can sense reaction force.

Note that the present invention is not limited to the above configuration. For example, as shown in FIG. 2, only the torque detector 4 on the slave arm 2 side may be used to generate the drive signal for the master arm 1. With such a configuration, it is possible to reduce the number of detectors by two per degree of freedom.

Furthermore, the method of the present invention can be applied to master-slave manipulators having different structures, such as a master arm having a three-degree-of-freedom orthogonal coordinate system and a slave arm having a three-degree-of-freedom rotary joint type. In the control device shown in FIG. 3, two slave arms can be used. The speed command value from the master arm 1 is converted into the slave coordinate system by multiplying it by the slave inverse Jacobian matrix in the coordinate conversion section 16.

An angular velocity signal to the motor drive section 13 is generated. - way,
Force T3 detected by torque detector 4 of slave arm 2
after being compensated for its own weight by the gravity compensator 17.

The coordinate transformation unit 18 transforms the coordinate system into a mask coordinate system by multiplying it by an inverse device Jacobian matrix, and force information for the amplifier 9 is generated. By performing control in this manner, speed command type control in which the force applied to the slave arm is fed back to the master arm is possible even in master-slave manipulators having different structures.

As described above, if the force acting on the slave arm is fed back to the master arm and the displacement of the master arm is used as movement speed information of the slave arm to drive the slave arm, it is necessary to apply a servo lock to the master arm. This realizes a speed command type master/slave manipulator that has no force sensation on the master arm.

〔Effect of the invention〕

As described above, according to the present invention, a speed command type master/slave manipulator with improved stability is realized.

[Brief explanation of drawings]

1 to 3 are block diagrams showing a control device for a master/slave manipulator according to the present invention, and FIG.
A graph showing the relationship between the displacement amount and the output speed signal in the speed signal converting means. FIG. 5 is a graph showing the relationship between the displacement amount and its coefficient in the displacement/force signal converting means. 1... Master arm 2... Slave arm 3
．． 4...Torque detector (force detection means) 5.6...Position detector (position detection means) 12...Controller (displacement/speed signal conversion means) 14...Restoring force generator (displacement・Force signal conversion means) Agent Patent attorney Noriyuki Chika Yudo Mitsuyuki Matsuyama

Claims (4)

[Claims] (1) A method for controlling a master/slave manipulator, characterized in that the force acting on the slave arm is fed back to the master arm, and the displacement amount of the master arm is used as movement speed information of the slave arm to drive the slave arm. . (2) The method for controlling a master/slave manipulator according to claim 1, characterized in that the amount of displacement of the master arm is fed back to the master arm as force information. (3) a detection means included in at least the slave arm for obtaining a drive signal for the master arm; a position detection means provided for the master arm in order to obtain the drive signal for the slave arm; A control device for a master/slave manipulator, comprising: a displacement/velocity signal conversion means that generates a velocity signal according to the displacement amount of the master arm based on the signal and uses it as a drive signal for the slave arm. (4) Displacement/force signal conversion means that generates a force signal according to the amount of displacement of the master arm based on the signal from the position detection means and uses it as part of the drive signal for the master arm. A control device for a master/slave manipulator according to claim 3.