JPH0829507B2 - Force sensing type manipulator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a force-sensitive manipulator.

[Conventional technology]

As a manipulator of this type, the one described below has been widely put into practical use.

(Symmetrical Load Force Sensing Method) A master actuator lever is provided with a torque actuator such as a torque motor, and a drive signal based on a positional deviation between the lever and a slave working machine is applied to the torque actuator. Since the position deviation is proportional to the load force acting on the work machine, the operator can sense the load force through the control lever.

This manipulator does not require a special load force detector, and has a simple structure and high reliability. Also, since the position servo system also works on the control lever, even if the control lever is driven in reverse from the work machine side, the position of the control lever and the work machine does not shift, and therefore stable. It is possible to operate.

(Force feedback type load force sensing method) The load force of the working machine is detected by the hydraulic pressure of a hydraulic cylinder for driving the working machine or a strain gauge attached to the working machine,
A torque actuator attached to the steering lever is driven by a drive signal corresponding to this load force. Therefore, in this type of manipulator, the load force is directly fed back to the steering lever and sensed by the operator.

In this manipulator, since the load force is transmitted to the control lever side via the force servo system independent of the position servo system, the load force sensing performance is high and the impact force transmissibility is also excellent. In addition, since the force servo system acts so as to make the force acting on the control lever zero during no-load operation,
There is also an advantage that the operating force of the control lever is not affected by the viscous resistance and frictional resistance of the lever.

[Problems to be solved by the invention]

The symmetrical load force sensing type manipulator has a drawback in that the load force is once converted into position deviation and then transmitted to the control lever side, so that the manipulator is inferior in sensitivity to impact force acting on the working machine.

Also, in this manipulator, since the viscous resistance and frictional resistance of the control lever directly affect the lever operation force, some kind of compensation is usually required to obtain good load sensing performance, but if the viscous resistance component is completely removed. There is also a problem that the operation of the control lever becomes unstable and the original high stability of the symmetric type is easily impaired.

On the other hand, in the manipulator of the force feedback type load force sensing system, since the position servo system is not added to the control lever, there is a drawback that the operation tends to be unstable when the control lever is reversely driven from the working machine side. is there.

An object of the present invention is to provide a manipulator of high stability capable of compensating the drawbacks of the manipulators according to the above-mentioned methods and having a high load sensing ability.

[Means for solving problems]

The present invention provides a force-sensitive manipulator configured to include position deviation detecting means for detecting a position deviation between a master and a slave, and to operate an actuator on the slave side so that the slave follows the master based on the position deviation. A force detecting means for detecting the force acting on the slave, and means for applying a drive signal based on the sum of the outputs of the position deviation detecting means and the force detecting means to the torque actuator on the master side. I am trying.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a basic configuration diagram showing an embodiment of a force sensing type manipulator according to the present invention.

In this figure, the master control lever 1 has a shape similar to that of the slave work implement 2, and its rotation shaft portion has a position sensor 3 such as a potentiometer for detecting the rotation position θ _m, and its rotation. A torque actuator 4 (for example, a torque motor, a servomotor, etc.) that exerts a torque on the moving shaft, and a force sensor 5 (for example, a magnetic torque sensor, a torsion torque sensor) that detects a rotational force acting on the rotating shaft are provided. Has been done. The torque actuator 4
Is provided to apply a torque to the lever 1 in a direction opposite to the operating direction thereof.

On the other hand, a position sensor 6 such as a potentiometer for detecting the rotation position θ _s is provided on the shaft of the work machine 2. Further, the servo valve 7 is provided at the center of the working machine 2.
Piston rod of hydraulic cylinder 8 to which hydraulic pressure is applied via
8a is pivotally attached. A pressure sensor 9 for detecting the differential pressure of the pressure oil flowing between the servo valve 7 and the hydraulic cylinder 8 is provided between the pair of oil passages. The output of the pressure sensor 9 indicates the load force acting on the work machine 2.

The outputs of the position sensors 3 and 6 are added to the subtractor 10,
Here, the difference between the two, that is, the positional deviation ε between the lever 1 and the working machine 2
₁ = θ _m −θ _s is detected. The output of the subtractor 10 is applied to the servo valve 7 via the servo amplifier 11 and, after being appropriately weighted by the amplifier 17, added to the adder 16.

On the other hand, the outputs of the force sensor 5 and the pressure sensor 9 are applied to the subtractor 14 via the amplifier 12 and the amplifier 13. In the subtractor 14, the difference between the outputs of the amplifier 12 and the amplifier 13, that is, the deviation ε of each force acting on the lever 1 and the working machine 2
₂ is detected, and the signal showing the deviation ε ₂ is added to the adder 16 after being appropriately weighted by the amplifier 15. The output of the adder 16 is applied to the torque actuator 4 via the drive amplifier 18.

In the manipulator according to the above embodiment, the driving force of the position servo system based on the deviation ε ₁ and the driving force of the force servo system based on the deviation ε ₂ act on the torque actuator provided on the operation lever 1.

That is, when the control lever 1 is operated, the position deviation ε
_The hydraulic cylinder 8 is driven in the direction of decreasing ₁ , so that the working machine 2 is operated in a manner to follow the lever 1. At this time, since the drive signal based on the position deviation ε ₁ is applied to the torque actuator 4 via the adder 16, the torque corresponding to the load force acting on the working machine 2 is opposite to the operating direction of the lever 1. Acts in the direction of. This is because when the load force is small, the verticality of the work implement 2 is good, so the deviation ε ₁ is small, and when the load force is large, the verticality is decreased and the deviation is large, so the lever 1
A torque corresponding to the magnitude of the load force acts on.

On the other hand, in the force servo system, the deviation ε ₂ between the output of the pressure sensor 9 and the output of the force sensor 5, which indicates the load force of the work machine 2,
Is applied to the torque actuator 4 via the adder 16.

Thus, the torque actuator 4 has a deviation ε ₁ ,
A drive signal based on both ε ₂ is applied, which allows the operator to sense the load force via the steering lever 1.

This embodiment, in which both the position servo system and the force servo system are provided on the control lever 1, combines the advantages of the symmetrical load force sensing type manipulator and the force feedback type load force sensing type manipulator described above. Can compensate for the drawbacks of both methods.

That is, since the position servo works on the control lever,
The disadvantage that the control lever 1 is reversely driven from the working machine side is prevented. Further, since the load force is directly transmitted to the control lever 1 side via the force servo system, the load force sensing performance is high. Therefore, for example, when an impact force acts on the working machine 2, this impact force is transmitted to the control lever side. Can be promptly and accurately transmitted.

FIG. 2 shows an embodiment of the present invention in which measures are taken to stabilize the operation, and the basic configuration and function are the same as those of the embodiment shown in FIG.

In this embodiment, a speed sensor 21 (for example, a tachogenerator) that detects the operating speed _m is provided on the shaft of the control lever 1, and the rotation speed of the shaft of the working machine 2 is set.
A speed sensor 22 for detecting _s is provided.

The outputs of the speed sensors 21 and 22 are applied to the subtractor 23, where the speed deviation ε ₃ = _m − _s is detected. The output of the subtractor 23 is negatively fed back to the output of the adder 16 via the amplifier 24 and the subtractor 25.

As a result, according to this embodiment, the steering lever 1 is provided with sufficient damping, whereby the operation on the lever 1 side is stabilized.

On the other hand, the output of the subtractor 23 is the amplifier 26 and the adder.
Positive feedback is provided to the servo amplifier 11 via 27. Therefore, in this embodiment, the natural frequency of the working machine 2 can be improved.

Further, in this embodiment, the output of the speed sensor 22 is the amplifier 28
And the positive feedback is performed to the servo amplifier 11 via the adder 29. Therefore, it is possible to prevent the inconvenience that the position deviation (so-called droop) depending on the operation speed affects the force transmission signal based on the deviation ε ₁ .

Further, in this embodiment, the output of the pressure sensor 9 is an amplifier.
It is negatively fed back to the servo amplifier 11 via 30 and the subtractor 31. Therefore, the working machine 2 that normally has a large inertial load
It is possible to provide sufficient damping to stabilize the operation.

In the above embodiment, a manipulator having a uniaxial structure is shown for the sake of simplicity, but the present invention is naturally applicable to a manipulator having a multiaxial structure.

〔The invention's effect〕

As is clear from the description of the above embodiment, in the force sensing type manipulator according to the present invention, the drawbacks of the symmetrical type manipulator and the force feedback type manipulator described above are mutually compensated, and the advantages of both types are provided. Since it is utilized, the steering characteristics with high stability and excellent load force sensing performance can be obtained.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of a force sensing type manipulator according to the present invention, and FIG. 2 is a basic configuration diagram showing another embodiment of a force sensing type manipulator according to the present invention. 1 ... Steering lever, 2 ... Working machine, 3,6 ... Position sensor, 4 ... Torque actuator, 5 ... Force sensor, 7
…… Servo valve, 8 …… Hydraulic cylinder, 9 …… Pressure sensor, 10,14 …… Subtractor, 11 …… Servo amplifier, 16 …… Adder, 21,22 …… Speed sensor, 23,25,31 ...... Subtractor, 2
7,29 …… Adder.

Claims (1)

[Claims] 1. A force sensing type device comprising position deviation detecting means for detecting a position deviation between a master and a slave, wherein the slave operates an actuator on the slave side so that the slave follows the master based on the position deviation. In the manipulator, force detecting means for detecting a force acting on the slave, speed deviation detecting means for detecting a speed deviation between the master and the slave, output of each of the position deviation detecting means and the force detecting means. And a drive signal based on a value obtained by subtracting the output of the speed deviation detection means from the sum, and means for applying the drive signal to the torque actuator on the master side.