JPH04130904A - Control device for master/slave manipulator - Google Patents

Abstract

PURPOSE:To attain a master/slave manipulator control device strong even at idle time and excellent in stability and operability at working time by executing virtual symmetry type bilateral control using impedance. CONSTITUTION:The 1st control part 13 on the real master side 3 controls the feedback of an output xm outputted from the 1st motion value detecting part 11 for a real master arm 5 based upon the motion value xmi of a virtual master arm 17 and generates a command from the 1st driving part 7 for the arm 5. On the real slave side 23, the feedback of an output xs outputted from the 2nd motion value detecting part 31 for a real slave arm 25 is controlled based upon the motion value xsi of a virtual slave arm 37 and a command is generated from the 2nd driving part 27 of the real slave side 23. Thus, respective real arms 5, 25 can follow the positions of their corresponding virtual arms 17, 27.

Description

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

(Prior Art) A master-slave manipulator (hereinafter referred to as "master-slave") allows the operator to easily operate the device on the mask side, while the slave side accurately follows the operator's movements and performs the work. It is important to allow the operator to accurately sense the time reaction force through the mask. For this reason, in the bilateral control system, symmetrical type, force reversal type,
The control method changed to a force feedback type.

The above-mentioned force feedback type uses force control to compensate and reduce the frictional force present in the master arm, and is said to be a pirate type control system with good operability.

However, it has recently become clear that stability during work deteriorates due to the slave's follow-up delay (JRA
J, vol, 7, 1989.446-452.
``Parallel Control Method of Pilateral Master-Slave Manipulator''). Against this background, various control methods began to be announced, and in February 1988, the Society of Instrument and Control Engineers (February 1988, Proceedings of the Society of Instrument and Control Engineers, Vol. 24, 2
A master-slave system using a virtual model was proposed in the previous issue.

This virtual model following type master slave will be explained below. This control uses an arbitrarily set virtual mask and virtual slaves, and the virtual mask is moved by the resultant force of the operating force applied to the real mask and the external force applied to the four real slaves. The real mask is optimally controlled and driven so as to follow the movement of the virtual mask at this time. The position of the virtual slave is controlled with the movement of the virtual mask as the goal, but in addition (an external force applied to the virtual slave is applied to the virtual slave,
This causes the virtual mask and virtual slave to have a deviation. This deviation is determined from the impedance of the position control system between the virtual mask and the virtual slave, and as a result, the virtual slave moves with respect to the virtual mask while allowing a deviation of the impedance. The real slave is
As with the real mask, the position is controlled and driven using optimal control with the virtual slave as the target.

By allowing impedance on the slave side in the above-mentioned virtual model following type master slave, a relatively stable force feedback type bilateral control system is constructed even if there is a follow-up delay in the slave.

However, if the impedance on the slave side is high, the problem of instability during work due to force feedback still occurs. On the other hand, if the impedance is reduced, the positional deviation between the mask and the slave increases during work, making it difficult to operate the slave freely and at the same time decreasing the sensitivity of reaction force during work.

For these reasons, a parallel type bilateral control method, which is a modification of the virtual model following type, has been proposed. The parallel type is
This method uses one virtual manipulator as a model, applies the resultant force of external forces applied to a real mask and a real slave to the virtual model, and controls the position so that the movement of this model is followed by the real mask and real slaves.

Since the mask and slave follow the same target, there is no delay between the mask and slave, allowing stable control during work. Furthermore, since there is no deviation between the mask and the slave, it is easy to operate the slave, and the operator can feel the external force applied to the slave with good sensitivity.

In this way, parallel control can be said to be a desirable control method as a master-slave control method, but this control can only be achieved in an ideal state where there is no dead time of signals. In other words, in systems where slave signals are processed as serial signals on the mask side, or in systems where there is a delay in signal transmission due to remote work that is very far away, there is wasted time on one side, so parallel processing between the mask and slave is necessary. This has the disadvantage that the premise of this is broken and resonance occurs as a result.

On the other hand, the master-slave using the virtual model proposed by the Society of Instrument and Control Engineers assumes a delay in the slave, so it is relatively robust against signal transmission delays.
In systems with dead time, it is superior to parallel types in terms of stability.

(Problems to be Solved by the Invention) As described above, the conventional master-slave control system still lacks a decisive factor in terms of wasted time, has advantages and disadvantages, is unstable during work, and is difficult for the operator to control as a slave. Sensitivity to external forces was poor.

In consideration of the above facts, the present invention provides a control method and a master slave that are relatively robust in terms of dead time, have excellent stability during operation, and allow an operator to sense slave external forces with relatively high sensitivity. is the purpose.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the invention described in claim (1) provides the following:
a virtual master arm; a third motion value detection unit that represents the movement of the virtual master arm; a third drive unit that inputs the result detected by the first force detection unit to drive the virtual master arm; a slave arm, a fourth motion value detection unit representing the motion of the virtual slave arm, and the second
a fourth drive unit that inputs the result detected by the force detection unit to drive the virtual slave arm; a coupling unit that connects the virtual master arm and the virtual slave arm via impedance; and a third motion value detection unit. The output of is set as the target value,
A first control section that performs feedback control on the output of the first motion value detection section and outputs it to the first drive section; and a first control section that performs feedback control on the output of the first motion value detection section and outputs the output of the fourth motion value detection section as a target value, and the output of the second motion value detection section. The present invention is characterized in that it includes a second control section that performs feedback control and outputs the feedback control to the second drive section.

In the invention according to claim (2), the first, second, third,
a fourth motion value detection section, and the first and second force detection sections;
It is characterized by connecting the coordinate conversion means between the master arm coordinate system and the common coordinate system, and the coordinate conversion means between the slave arm coordinate system and the common coordinate system.

Further, the coupling means may be formed of a spring and a damper.

(Function) According to the invention described in claim (1), when an operating force is applied to the master arm, the first force detection section detects this operating force,
The operating force is transmitted to the virtual master arm via the third drive section. If an operating force is applied to the slave arm at the same time, the second
The force detection section detects this operating force and transmits the operating force to the virtual slave arm via the fourth drive section.

The third drive unit of the virtual mask normally applies the operating force as it is to the virtual mask, but the fourth drive unit on the virtual slave side
The drive unit increases or decreases the external force based on the force reflectance and applies it to the virtual slave as an external force.

The virtual master arm and the virtual slave are coupled through impedance, so the virtual master arm
The virtual slave arm is subjected to a force exerted by the coupling means.

That is, the virtual master arm moves due to the operating force and the force acting on the coupling means, and the virtual slave arm moves due to the external force and the force acting on the coupling means. These movements of the virtual arm are detected by the third and fourth movement value detection sections, and the force acting on the coupling means is successively changed. The simultaneously detected motion values are input as target values for the first control means and the second control means. That is, the first control section generates a command for the first drive section by feedback-controlling the output from the first motion value detection section, with the motion value of the virtual mask as a target, and the second control section generates a command for the first drive section. With the motion value as a target, the output from the second motion value detection section is feedback-controlled to generate a command for the second drive section.

This causes the master arm and slave arm to follow the positions of the corresponding virtual master arm and virtual slave arm.

Therefore, in conventional symmetrical bilateral control, a very large operating force was required due to the effects of friction and inertia existing in the master arm and slave arm. By introducing an arm and a virtual slave arm, it has become possible to configure a master slave with an ideal arm with extremely low inertia and no nonlinear friction. That is, the virtual symmetrical bilateral control of the present invention constructs a symmetrical pirate via coupling means for these virtual arms, and the master arm and slave arm follow the movement of the virtual arm.

Further, by using an impedance such as a spring damper as a coupling means, an impedance can be interposed between the master arm and the slave arm.

As in the past, in the virtual model following master-slave, only the slave has an impedance with respect to the mask, and basically inherits force feedback.

In contrast, the present invention is a control device that basically has a symmetrical bilateral with impedance intervening as a virtual model, and is clearly different from the above.

In addition, if the intervening impedance is infinite, that is, a rigid connection, the result will be equivalent to a parallel type bilateral,
Although this parallel type is included in the bilateral, it is different from the conventional method in that an impedance is interposed between the two virtual models, making it relatively robust against wasted time.

The virtual symmetrical pirate of the present invention uses an impedance, but unlike the force feedback type, the virtual mask and the virtual slave are connected by a symmetrical coupling means, so it is difficult to work when the same impedance is introduced. The stability is far superior to the conventional virtual model following type. Therefore, if the stability against dead time is set to be the same, the impedance can be set higher, and as a result, the slave reaction force can be transmitted to the operator with relatively high sensitivity.

In the case of very remote locations such as Earth and space, there is significant wasted time and it becomes necessary to manage virtual models separately. Therefore, instead of a coupling means having an impedance such as a single spring/damper system, a coupling means having an impedance element for each mask/slave is required. However, since the dead time is very large, even if these coupling means are used, the impedance at the stability limit is quite small, and the operability is somewhat sacrificed.

(Embodiment) Next, an embodiment of the master-slave manipulator control device according to the present invention will be described with reference to FIGS. 1 to 4.

First Embodiment FIG. 1 shows the configuration of a master-slave manipulator control device (hereinafter referred to as "control device") 1 of a first embodiment. This control device 1 includes a real mask side 3, a virtual mask side 15, a real slave side 23, a virtual slave side 35, a coupling means 43 for coupling the virtual mask side 15 and the virtual slave side 35, and a real mask side 15. It is composed of a first control section 13 for performing feedback control on the side 3 and a second control section 33 for performing feedback control on the actual slave side 23.

On the real mask side 3, there is a first drive section 7 that drives the real master arm 5, a first force detection section 9 that detects an external force applied to the real master arm 5, and a first movement representing the movement of the real master arm 5. It is composed of a value detection section 11.

On the virtual mask side 15, a third drive #19 for driving the virtual master arm 17 by inputting the operating force detected by the first force detection unit 9, and a third motion value detection representing the motion of the virtual master arm 17 are provided. A section 21 is provided.

The real slave side 23 includes a second drive section 27 that drives the real slave arm 25, a second force detection section 29 that detects an external force applied to the real slave arm 27, and a second drive section 27 that drives the real slave arm 25.
A second movement value detection unit 31 representing the movement of No. 7 is provided.

The virtual slave side 35 includes a fourth drive unit 39 that receives the operating force detected by the second force detection unit 29 and drives the virtual slave arm 37, and a fourth motion value detection unit that represents the movement of the virtual slave arm 37. A section 41 is provided.

The first motion value detection section 11 also includes a first motion value detection section 1
A first control unit 13 is provided that performs feedback control on the output of the first drive unit 1 and outputs the same to the first drive device 7 .

Furthermore, the second motion value detection section 31 is provided with a second control section 33 that performs feedback control on the output of the second motion value detection section 31 and outputs it to the second drive section 27 .

FIG. 2 is a schematic diagram of the coupling means 43 when the dead time is not large, and is composed of a spring damper.

When the motion value xmiSxsi is input to the coupling means 43,
Both end portions of the spring portion 45 and the damper portion 47 move, thereby generating reaction forces fcm and fcs by the coupling means 43 as shown in the following equations.

fcmm-fcs.

fcm-d(large si-large mi) +k(large si-*mi (large represents speed).In other words, in this case, equal force is applied to the virtual mask side 15 and the virtual slave side 35 as the force acting on the coupling means. can be conveyed to.

Note that this time, only the motion information is input to derive the force acting on the coupling means, but the operating force fmi and external force fci are input to the coupling means 43 together with the motion value, and an impedance element is constructed with position, force, and a hybrid configuration. You may do so.

FIG. 3 is a schematic diagram of the coupling means when the dead time is relatively large. In the same figure, the broken line portions 51 and 53 indicate the second
This is an impedance element similar to the spring portion 45 and damper portion 47 shown in the figure.

The reason for adopting the configuration shown in Figure 3 is that if there is a large amount of wasted time on one side, the overall symmetry will be disrupted, resulting in a system that is not much different from the force feedback type in which master and slave are connected in series. This is because it will only be possible to obtain the same effect as the virtual model following type.

Furthermore, the dead time element 49 in FIG. 3 represents a delay in transmission, and the virtual mask side, mask side control section, and coupling means left side 51 are constructed on the computer on the mask side, and the virtual slave side, slave side control section And the coupling means right side 53 will be constructed on the slave side computer. Further, in the same figure, since the movement value of one of the coupling means 51 and 53 has a delay corresponding to dead time, the acting forces from the coupling means do not normally match on the mask and slave in a dynamic state.

Next, the operation of the control device 1 according to the present invention will be explained.

When an operating force f0 (not shown) is applied to the actual master arm 5,
The first force detection section 9 detects this as the operating force fm, and applies the operating force to the virtual master arm 17 constructed on the computer via the third drive section 19 of the virtual mask. Similarly, the second force detection section 29 on the slave side 23 is connected to the actual slave arm 25.
An external force fw (not shown) during work that is applied to the controller is detected as an external force fs, and the external force is applied to a virtual slave arm 37 constructed on a computer via a fourth drive unit 39. The third drive unit 19 of the virtual mask has a normal operating force f. is applied as is to the virtual master arm 17 as the operating force fmi, but the fourth drive unit 39 on the virtual slave side 35 increases or decreases the external force by force reflection and applies it to the virtual slave arm 37 as the external force fsi.

Since the virtual master arm 17 and the virtual slave arm 37 are coupled by the coupling means 43 having impedance, each virtual arm 17.37 receives the acting force fcmS fcs by the coupling means 43. That is, the virtual master arm 17 is moved by the operating force fmi and the coupling means acting force fcm, and the virtual slave arm is moved by the external force fsi and the coupling means acting force fcs.

The movements of these virtual arms are detected by each movement value detection means 21.
41, the force acting on the joint is fcm.

Change fcs sequentially. Motion value xm detected at the same time
i, xs i is the first control unit 13 of each real arm 5.25
, is input as a target value of the second control section 33.

That is, the first control section 13 on the real mask side 3 performs feedback control on the output xm from the first motion value detection section 11 of the real master arm 5, targeting the motion value xmi of the virtual master arm 17, and A command for the first drive section 7 of the arm 5 is generated.

On the other hand, the real slave side 23 performs feedback control on the output xs from the second motion value detection section 31 of the real slave arm 25, aiming at the motion value xsi of the virtual slave arm 37, and controls the second drive of the real slave side 23. A command for the unit 27 is generated.

This causes each real arm 5.25 to follow the position of the corresponding virtual arm 17.37.

As described above, according to this embodiment, it is possible to realize a control device for a master-slave manipulator that is robust against dead time and has excellent stability and maneuverability during work.

Furthermore, it is effective for master-slave manipulators in extremely remote work or in cases where signal processing is required for information transmission between the mask and slave, and there is wasted time.

Second Embodiment Next, a second embodiment will be explained using FIG. 4. This embodiment is an example in which the present invention is applied to a master-slave manipulator with a different structure (the master manipulator and the slave manipulator have different structures). Note that the same components as those of the control device 1 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals in the drawing, and a description thereof will be omitted.

As shown in FIG. 4, the control device 61 of this embodiment includes:
Coordinate conversion means 19a included in the third drive section on the mask side
A coordinate conversion means 39a included in the fourth drive section on the slave side is provided.

In addition, the first control section 13 on the mask side includes a coordinate transformation means 1.
3a and 13b are provided, and the second control unit 33 on the slave side
Also provided are coordinate conversion means 33a and 33b.

In the control device 61 configured in this way, an operating force f (not shown) is applied. is applied to the real master arm 5, the first force detection unit 9 detects the operating force tm in the master arm coordinates, and the third drive unit 19 of the virtual master arm 17 constructed on the computer
tell. The third drive section 19 includes the coordinate conversion means 1
The fourth drive unit 39 of the virtual slave arm 37 that calculates the common operating force fm using the 9g and has a common coordinate structure similarly constructed on the computer also includes the coordinate conversion means 39.
Using a, the external force ts at the slave arm coordinates of the external force fw (not shown) applied to the real slave arm 25 during work is converted into a common coordinate external force fs, and the external force fsi is applied to the virtual slave arm 37 having the common coordinates.

The third drive unit 19 of the virtual mask usually only applies the operating force fm converted into common coordinates as the operating force f to the virtual master arm 17, but the fourth drive unit 39 on the virtual slave side applies the external force converted into common coordinates. The fs is increased or decreased by force reflection and is applied to the virtual slave arm 37 as an external force fsi.

Since the virtual master arm 17 and the virtual slave arm 37 are coupled by a coupling means 43 having impedance, each virtual arm receives a force fcm exerted by the coupling means 43.
Receive S fcs. That is, the virtual master arm 17 moves by the operating force fmi and the coupling means acting force fcm,
The virtual slave arm 37 moves by the external force fsi and the coupling means acting force fcs. The interlocking of these virtual arms is detected by the third motion value detection section 21 and the fourth motion value detection section 41, and the coupling means acting forces fcm and fcs are successively changed. At the same time, the detected motion values xmi and xsi are input as target values to the first control section 13 and second control section 33 of each actual arm.

On the other hand, the output pm from the first motion value detection unit 11 of the real mask
is converted into motion information xm expressed in common coordinates via the coordinate conversion means 13a included in the first control section 13 of the real mask; the first control section 13 converts the two motion values xmSxmi expressed in common coordinates Based on the common coordinate mask control information vrm
generate.

The first control section 13 further converts this mask control information Vrm inversely into mask control information ωrm in the master arm coordinate system using the coordinate conversion means 13b, and outputs it as a command to the first drive section 7 of the mask.

Similarly, the output p from the second motion value detection unit 31 of the actual slave
s is converted into motion information xs converted into common coordinates via a coordinate conversion means 33a included in the second control unit 33. Second
The control unit 33 controls two motion values xsi expressed in common coordinates.
, xs to generate slave control information vrs of common coordinates. The third control unit 33 further controls this slave information vr.
s is inversely transformed into slave information ωrs in the slave arm coordinate system by the coordinate transformation means 33b, and outputted as a command to the second drive section 27.

Further, the coordinate transformation means 19a, 13a, 13b use the movement information Pm of the mask arm, while the coordinate transformation means 39
a% 33a and 33b are updated one after another using the coordinate conversion means Ps of the slave arm. As a result, the movement of the coordinate transformation corresponding point of each real arm 5.23 follows the movement of the coordinate transformation corresponding point of each virtual arm 17.37.

Note that in this example, the motion values of the real arm are converted into common coordinates, and inverse coordinate transformation is performed after controlling using two motion value information on the common coordinates, but as in the known different structure control method, virtual Control of each axis may be performed after converting the motion value information of the arm into each arm coordinate system.

Furthermore, in this embodiment, the coordinate transformation means is included in the drive unit or the control unit of the virtual arm, but the coordinate transformation may be performed at any point in time.

[Effects of the Invention] As explained above, the master-slave manipulator control device according to the present invention is robust against wasted time and has improved stability and operation during work due to the virtual symmetrical bilateral structure with impedance intervening. This makes it possible to realize a control device for a master-slave manipulator with excellent performance, especially for very remote work or when signal processing is required to transmit information between the mask and slave, and there is wasted time. The excellent effect of being effective against slaves can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the master-slave manipulator control device according to the present invention, and FIG. 2 is a schematic diagram showing the configuration of the coupling means when dead time is small.
FIG. 3 is a schematic diagram showing the configuration of the coupling means when the dead time is relatively large, and FIG. 4 is a block diagram showing the configuration of the master-slave manipulator control device of the second embodiment. 1.61... Master-slave manipulator control device (control device) 3... Actual mask side 5... Actual master arm 7... First drive section 9... First force detection section 11... -First motion value detection unit 13...First control unit 15...Virtual mask side 17...Virtual master arm 19...Third drive unit 2
1...Third motion value detection section 23...Actual slave side 25...Actual slave arm 27...Second drive section 31...Second motion value detection section 33...Second control section 35...Virtual slave side 37...Virtual slave arm 39...Fourth drive section 41...Fourth motion value detection section 43...Coupling means 45...Spring section 47...Damper section 29...Second force detection section

Claims (2)

[Claims] (1) a first motion value detection unit representing the motion of the master arm;
a first force detection section that detects an external force applied to the master arm;
A first drive section that drives the master arm, a second motion value detection section that represents the movement of the slave arm, a second force detection section that detects an external force applied to the slave arm, and a second drive section that drives the slave arm. A control device for a master-slave manipulator, comprising: a virtual master arm; a third motion value detection unit representing the movement of the virtual master arm; and a result detected by the first force detection unit, which is input to the virtual master arm; a third drive unit that drives the master arm; a virtual slave arm; a fourth motion value detection unit that represents the movement of the virtual slave arm;
a fourth drive unit that inputs the result detected by the force detection unit to drive the virtual slave arm; a coupling unit that connects the virtual master arm and the virtual slave arm with impedance interposed therebetween; and a third motion value detection unit. The output of the first motion value detection section is set as a target value, the output of the first motion value detection section is feedback-controlled and outputted to the first drive section, and the output of the fourth motion value detection section is set as the target value, and the output of the fourth motion value detection section is set as the target value. A control device for a master-slave manipulator, comprising: a second control section that performs feedback control on the output of the two motion value detection sections and outputs it to a second drive section. (2) The first, second, third, and fourth motion value detection units and the first and second force detection units include coordinate conversion means between a master arm coordinate system and a common coordinate system, and a slave arm coordinate system. A control device for a master-slave manipulator according to claim 1, characterized in that a coordinate conversion means for the system and a common coordinate system is connected.