JPS5949153B2 - Master/slave type servo manipulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a force reflex (bilateral) type device in which the load torque on the slave (driven) side is fed back as a sensation of the force of the operator's hand, arm, etc. operating the master (active) side. Regarding master-slave type servo manipulator.

As a conventional manipulator of this type, there is a double-acting servo mechanism shown in FIG.

The figure shows an electric type, and when the operator rotates the master shaft IM in a certain direction, the resulting angular deviation signal εθ between the master shaft IM and the slave shaft Is is detected by the angle detectors 2M and 2s. This signal εθ is detected and used as a driving force for a servo 4s through a servo amplifier 3s on the slave side, and the servo motor 4s drives the slave axis Is in a direction in which the angle θ2 coincides with the angle θ1 of the master axis IM. On the other hand, torque detectors 5M and 5s provided on both axes IM and ls generate torques Tl and T2, respectively.
is detected, the deviation signal εT is given to the servo amplifier 3M on the master side, and the torque T of the master shaft IM is increased by the servo motor 4M driven by the output of this amplifier 3M.
It is driven so that l matches the torque T2 of the slave shaft Is. Thus, the angular displacement applied to the master axis IM is faithfully reproduced on the slave axis Is, and
The operator who operates the master shaft IM can feel the torque (force) corresponding to the load of s. This manipulator has excellent workability because there is a reaction from an object in addition to the visual operation status, but in order to accurately match the angle of the slave axis with that of the master axis and to increase the response speed, a servo amplifier 3s is required. , it is necessary to increase the amplification degree (gain) of 3M to increase the servo rigidity.

However, when the servo rigidity is increased, when the slave axis touches a highly rigid fixed object, a large slave axis torque T2 corresponding to the saturation torque of the servo motor 4s is suddenly generated on the master axis IM, making the operator stable. There was a problem that the aircraft could not be operated. The present invention provides a force reflection type master/slave type servo manipulator using a drive type servo mechanism that has excellent workability and maneuverability by providing local torque feedback and adding a nonlinear element to its control loop. purpose. FIG. 2 is a configuration diagram showing an embodiment of the present invention.

In the figure, the torque deviation signal εT=Kf2T2−KflTT detected by the torque detectors 5M and 5s of each axis is input to the master side servo amplifier 3M, amplified, and its output is supplied to the servo motor 4M. . In addition, the slave side amplifier 3s is provided with an angle deviation signal εθ=kθ (θ, −θ2) detected by the angle detectors 2M and 2s, which is obtained by inputting it into a converter 6 with linear or nonlinear characteristics. The difference (
ε2-52) is input, amplified, and its output is supplied to the servo motor 4s.

It is.

The equations of motion on the master side and slave side in the double-acting servo mechanism configured as above are as follows. Here it is.

If equations (1) and (2) are Laplace-transformed using four variables θ, θ2, T, , T2, then Z=R+SL.

When the slave shaft 1s has constant loads T and O, the operator's force sensations T and O when moving the master shaft 1M at a constant angular velocity ω10 are as follows.

In equation (4), the torque transmission ratio in the stopped state is ω,
o=0 or Ks+0, which is larger by Kkfl force, and can be set to any size by selecting the values of Kfl and kf2.

Even in the conventional servo mechanism described in FIG. 1, the torque transmission ratio is the same as equation (8). Next, let's compare the servo rigidity.

becomes.

When a certain angular displacement is applied to the master shaft with the scrape shaft fixed, the rigidity can be determined from the ratio of the final value of the master shaft torque and the applied angular displacement. In other words (in 9th grade,
ω2=Oθ1=θ10/STS=TsO/S(θ10,
If the final value of T when TSO is a constant) is TlO, then if Kk, kfln, kklkf2n>R, then it can be seen that.

According to equation (12), the servo stiffness not only changes depending on the amplification rate k of the amplifier, but also the resistance of the servo motor and the speed reducer, and also includes a large constant term. However, in the present invention, the rigidity can be controlled relatively freely because it can be determined using only three elements, kθ, . . . Kfl, as shown in equation (). As shown in equation (8), the torque of the master shaft is proportional to the load torque of the slave shaft. In other words, the master shaft constitutes a torsion spring that is twisted by the load torque, and its spring constant is (11)
Corresponds to the rigidity given by Eq. Moreover, kθ, G, kfl
If one of these (often the conversion coefficient g) is taken as a nonlinear characteristic element, the same characteristics of the nonlinear spring can be obtained. In particular, simply changing the magnitude of the coefficient g of the converter or operating it nonlinearly will not change the value of kθ or Kf.
Since l does not change, the positional relationship between the two shafts and the torque transmission ratio do not change. In particular, such non-linear spring characteristics reproduce the feeling that the operator is directly acting on the target object on the master axis, which further improves the sense of operation as a master-slave servo manipulator, making it easier to operate. Sexuality improves. Examples of the torque transmission ratio and spring constant (rigidity) are shown in FIGS. 3 and 4, respectively.

Further, FIG. 5 shows a specific embodiment of the present invention.

In the same figure, 2M, 2s are potentiometers that detect the angular displacement of the master shaft 1M1 and the slave shaft 1s, and 7, 8M
, 8s, 9M, and 9s are operational amplifiers that amplify or compare signals, and 11 is a converter that uses two multipliers and has nonlinear characteristics due to cubic characteristics or forward characteristics of a semiconductor PN junction. be. This transducer 11 can also be removed, then the nonlinear properties of the stiffness are lost. 4
M and 4s are power amplifiers, and 5M and 5s are servo motors, which are directly connected to the reducers of 10M and 10s, respectively.

6M and 6s are torque detection units using strain gauges, which detect the torque of the master shaft 1M1 and the slave shaft 1s.

The above is an example of an electric servo, but it goes without saying that it can be configured as an electric-hydraulic servo by using a hydraulic motor as the servo motor and speed reducer, and using hydraulic pressure as the torque detection.

As described above, the present invention employs a double-acting servo mechanism in a force reflection type manipulator that feeds back reaction from an object to the master side, and the present invention improves the torque transmission characteristics between the master and slave by localized torque feedback. It is possible to control servo rigidity without damage, and stable maneuvering is possible even against highly rigid fixed objects.

Furthermore, by adding non-linearity to rigidity control, the handling sensation and workability can be further improved.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional master-slave type servo manipulator, and FIG. 2 is a configuration diagram showing an embodiment of the present invention.
3 and 4 are characteristic diagrams for explaining the operation of FIG. 2, and FIG. 5 is a diagram showing a specific embodiment of the present invention. 1M...Master axis, 1s...Slave axis, 2M, 2s...Angle detector, 4M, 4s
... Servo motor, 5M, 5s ... Torque detector, 6 ... Characteristics converter, 10M, 10
s...Reducer, 11...Nonlinear characteristic converter.

Claims (1)

[Claims] 1. A first control system that drives the slave axis by amplifying the difference between a signal proportional to the angle or position deviation between the master axis and the slave axis and a signal proportional to the slave axis torque; A force reflection type master-slave type servo manipulator using a drive type servo mechanism, characterized in that it is equipped with a second control system that drives the master shaft by amplifying a signal proportional to the torque deviation between the torque and the master shaft torque. . 2. In claim 1, the first control system is configured to drive the slave shaft by amplifying the difference between a signal obtained by non-linearly converting a signal proportional to the angle or position deviation and a signal proportional to the slave shaft torque. A master who is characterized by
Slave type servo manipulator.