JP2501508Y2 - Bilateral master slave manipulator - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a bilateral master / slave manipulator, in particular, a force feedback type with improved friction compensation.

B, Outline of the Invention The present invention is a bilateral master / slave manipulator in which the friction compensation gain is changed according to the change of the weight compensation value.

C. Conventional Technology In a master / slave manipulator, when an operator operates a master arm, a slave arm connected to the master arm by an electric mechanism similarly operates in accordance with the movement of the master arm. In order to surely perform the work using such a master / slave manipulator, it is necessary not only to visually observe the operated side but also to know each situation of the operated side accurately. In particular, it is important for the operator to feel the feeling of grasping an object and the feeling of collision with an object in real time. Therefore, a bilateral master / slave manipulator having a feedback mechanism for sending a force applied to the slave side to the master side, that is, a bilateral feedback mechanism having a force transmission function has been developed.

Here, a conventional example of the force feedback type bilateral master / slave manipulator will be described with reference to FIG. FIG. 2 shows a control system for one axis, and other axes also perform similar control. Therefore, the configuration and operation for this one axis will be described as a representative.

In the figure, the master arm 1 is an articulated arm and is provided with a motor for generating a reaction force. Each axis of the master arm 1 is provided with a torque detector 2 for detecting the torque acting on the master arm 1 and a position detector 3 for detecting the position (rotational angle of each axis) of the master arm 1.

On the other hand, the slave arm 4 is a multi-joint type arm of the same type as the master arm 1, and is equipped with a motor for generating driving force. Each axis of the slave arm 4 is provided with a torque detector 5 that detects the torque generated by the slave arm 4 and a position detector 6 that detects the position (rotational angle of each axis) of the slave arm 4.

The position control of this manipulator is performed based on the position signal θ _M detected by the position detector 3 on the master side and the position signal θ _S detected by the position detector 6 on the slave side. That is, the position deviation Δθ (= θ _M −θ _S ) between the position signals θ _M and θ _S is sent to the position adjuster 7, and the position adjuster 7 puts the position deviation Δθ at zero, in other words, the signal. The motor of the slave arm 4 is drive-controlled so that θ _S matches the signal θ _M.

The force feedback control of the manipulator is performed based on the torque signal T _M detected by the torque detector 2 on the master side and the torque signal T _S detected by the torque detector 5 on the slave side. In principle, it is sufficient to control the master arm 1 to generate a reaction force according to the torque deviation between the signals T _M and T _S. Actually, feedback control is performed while compensating for the weight and friction of the master arm 1. That is, the torque signal T _M is multiplied by α (fixed gain of 1 or more) by the friction compensation calculator 8 to obtain the torque deviation ΔT between the friction compensation torque signal α T _M and the torque signal T _S. Further, the self-weight compensation calculator 9 obtains the attitude of the master arm 1 based on the position signal θ _M , and outputs a self-weight compensation value β (variable) for compensating the self-weight of the master arm in this attitude. Then, the torque deviation Δt obtained by adding the self-weight compensation value β to the torque deviation ΔT is sent to the torque adjuster 10, and the torque adjuster 10 causes the master arm to generate a reaction force corresponding to the torque deviation Δt.

In the force feedback described above, the friction compensation and the master arm 1 that increase the reaction torque in the direction in which the reaction force is generated are performed.
Since the self-weight compensation for canceling out the self-weight is performed, the operability of the master arm 1 is improved.

D. Problem to be Solved by the Invention By the way, although the friction of the master arm 1 differs depending on its posture, the friction compensation gain α by the conventional friction compensation calculator 8 is a fixed value. Therefore, the friction compensation cannot be completely executed in all the postures of the master arm 1. Further, the upper limit setting value of the friction compensation gain α (fixed value) cannot be made large because the self-weight compensation value β may increase or decrease, and there is a limit. Therefore, in a certain posture, the friction compensation is not sufficiently performed, and the operation of the master arm 1 becomes heavy.

The present invention has been made in view of the above-described conventional art, and an object of the present invention is to provide a bilateral master / slave manipulator capable of optimal weight compensation in all postures of a master arm.

E. Means for Solving the Problem In the present invention that achieves the above object, in a bilateral master / slave manipulator in which the self-weight compensation value β changes depending on the position of the master arm, friction is adjusted according to the change of the self-weight compensation value β. The point is to change the compensation value.

F. Action As the position (orientation) of the master arm changes, not only the weight compensation value but also the friction compensation value changes, and the master arm can be operated smoothly.

G. Embodiment FIG. 1 shows one axis of a force feedback type bilateral master / slave manipulator according to an embodiment of the present invention. In this embodiment, the position control is the same as the conventional one. That is, according to the deviation Δθ between the position signal θ _{M from} the position detector 3 included in the master arm 1 and the position signal θ _{S from} the position detector 6 included in the slave arm 4, the position adjuster 7 sets the slave arm 4 in position. Activate. Thus, the slave arm 4 moves so that the deviation Δθ becomes zero.

On the other hand, in the force feedback control system of this embodiment, the friction compensation gain varying device 12 is newly added and the gain in the friction compensation computing device 11 is made variable. That is, the friction compensation gain varying device 12 changes the gain γ of the friction compensator 11 in accordance with the increase or decrease of the self weight compensation value β obtained by the self weight compensator 9 (this value changes depending on the posture change of the master arm 1). Increase or decrease.

Therefore, in this embodiment, force feedback control is performed as follows. That is, the torque signal T _M is calculated by the friction compensation calculator.
The value is multiplied by γ (variable value) in 11 to obtain the friction compensation torque signal γT _M , and the torque deviation Δτ between the torque signal γT _M and the torque signal T _S is obtained. Further, the torque deviation Δτ ₀ obtained by adding the self-weight compensation value β to the torque deviation Δτ is sent to the torque adjuster 10, and the torque adjuster 10 causes the master arm to generate a reaction force according to the torque deviation Δτ ₀ .

After all, in this embodiment, the friction compensation gain γ decreases as the weight compensation value β decreases, and the friction compensation gain γ increases as the weight compensation value β increases.

Generally, when large self-weight compensation is required, large friction compensation is necessary, and when self-weight compensation may be small, friction compensation may be small. Therefore, in the bilateral master / slave manipulator of the present application, the master arm 1 can be moved with good operability regardless of how the position (posture) of the master arm 1 changes.

H. Effect of the Invention According to the present invention as described in detail with the embodiments above, the friction compensation is changed according to the position of the master arm, so that the manipulator operability is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a prior art. In the drawing, 1 is a master arm, 2 and 5 are torque detectors, 3 and 6 are position detectors, 7 is a position adjuster, 8 and 11 are friction compensation calculators, 9 is a weight compensation calculator, and 10 is a torque adjuster. Reference numeral 12 is a friction compensation gain varying device.

Claims (1)

(57) [Scope of utility model registration request] 1. A force feedback type bilateral master / slave manipulator in which a slave arm operates according to the movement of a master arm, and a force acting on the slave arm is generated in the master arm as a reaction force. a friction compensation computing unit resulting amplifies the torque signal T _M indicating the torque output as friction compensation torque signal [gamma] T _M, weight compensation value whose value changes to compensate for the own weight of the master arm in accordance with the attitude of the master arm The weight compensation calculator that outputs β and the deviation Δτ between the torque signal T _S indicating the torque generated in the slave arm and the friction compensation torque signal γT _M are added to the master arm according to the value obtained by adding the weight compensation value β. And a torque adjuster for generating a force, the friction compensation that changes the gain γ of the friction compensation calculator according to the weight compensation value β obtained by the weight compensation calculator. Bilateral master-slave manipulator, characterized in that it comprises a gain variable unit.