JPH085017B2 - Master / slave robot control method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control method for a master / slave robot.

[Conventional technology]

In remote control of a robot in outer space, the distance between the robot and the operator is large, which causes communication delay. In particular, when there is a control loop such as feedback between the robot and the operator, the longer the transmission delay, the more difficult the robot is to operate, and it was necessary to reduce the robot operating speed for stable operation. .

To solve these problems, a bilateral master / master that creates a dynamic characteristic model of the work object based on the dynamic characteristics of the work object of the slave robot, obtains a virtual reaction force from the model, and returns it to the operator. A method for configuring a slave robot has been proposed.

In addition, when a slave robot is used to carry a heavy object or to perform remote control in a highly viscous substance, it is difficult to return the reaction force from these operations to the operator as it is. Therefore, there has been proposed a method of changing a feeling of operation in which a model of a work target is created, and the model is adjusted to control the dynamic characteristics of the work target so as to be apparently changed to facilitate the operation.

[Problems to be Solved by the Invention]

When the robot measures the work object and creates a model thereof, an error occurs between the dynamic characteristics of the actual work object and the model.

In each of the above-described conventional techniques, the dynamic characteristic model of the work target is used, but since there is no mechanism for verifying the error of the dynamic characteristic model of the work target during the work, the error may occur while performing the work. May accumulate and the robot may not operate as intended by the operator.

The present invention has been made in view of the above circumstances, and it is possible to realize a master / slave robot that uses a dynamic characteristic model of an object to cope with a transmission delay or a change in operation feeling. The purpose is to propose a method for measuring the error between the dynamic characteristics of the work object and its model.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a method for controlling a master / slave robot, wherein when a hand of a slave robot contacts or grasps a work object, an actual motion V _S of the hand of the slave robot is V _S = (D ² X _s / dt ² ,, dX _s / dt, X _s ) where d ² X _s / dt ² : Acceleration of the slave robot's hand dX _s / dt: Speed of the slave robot's hand X _s : Slave robot Represents the position of the hand of the slave robot, and the motion model _s of the hand of the slave robot is _s = (d ² _s / dt ² , d _s / dt, ₂ ) where d ² _s / dt ² : acceleration of the hand of the slave robot d _s / dt: Velocity of the hand of the slave robot _s : When it is expressed as the position of the hand of the slave robot, the difference between the dynamic characteristics of the work object and its dynamic characteristic model e = ‖ _s −V _s ‖ , Weighted norm of velocity term and position term ‖ _s −V _s ‖ ＝ α | d ² _s / dt ² −d ² X _s / dt ² | + β | d _s / dt −dX _s / dt | + γ | _s −X _s | where α, β and γ are weighting factors (α + β + γ = 1) It is characterized in that when the norm exceeds a preset reference value, the operation of the slave robot is stopped and a warning is issued to prompt the operator to change the transmission delay or the operational feeling.

[Action]

From the internal sensor of the manipulator, the actual motion of the hand of the slave robot when the slave robot is touching or gripping the work object is measured, the motion model of the hand of the slave robot is calculated, and it is substituted in the above formula. ,
An error between the dynamic characteristic of the work target and the dynamic characteristic model can be obtained.

When this error exceeds a predetermined value, a warning is issued to the operator, and the operator changes the transmission delay and the operation feeling based on the warning.

〔Example〕

 Hereinafter, the present invention will be specifically described based on Examples.

The dynamic characteristic model (M ₀ , B ₀ , K ₀ ) of the work target
₀ , ₀ , ₀ ) is created.

The master robot dynamics (M _m , B _m , K _m ), the slave robot dynamics (M _s , B _s , K _s ), the slave manipulator dynamics and the object model For the combined model (,,), the motion of the master robot's hand is expressed as d ² X _m / dt ² : Master robot's hand acceleration dX _m / dt: Master robot's hand speed X _m : Master manipulator Let the position of the hand be the motion of the hand of the slave robot, and d ² X _s / dt ² : Acceleration of the hand of the slave robot dX _s / dt: Speed of the hand of the slave robot X _s : Position of the hand of the slave robot. A motion model that matches the dynamic characteristics of the object model and the slave robot is d ² _s / dt ² : acceleration of the hand of the slave robot d _s / dt: speed of the hand of the slave robot _s : position of the hand of the slave robot. FIG. 1 shows a block diagram of a master / slave robot using the model at this time.

In the figure, 10 is a master robot, 11 is its object model, 20 is a slave robot model, 21 is its object model, 30 is a slave robot, 31 is its object, 40 is a modeling error detector, 41 is a model. It is a conversion error determination unit.

Now, for the sake of simplicity, it is assumed that the dynamic characteristics of the master robot 10 are adjusted to be equal to the dynamic characteristics (M, B, K).

(M _m , B _m , K _m ) = (M _s , B _s , K _s ) = (M, B, K) At this time, the dynamic characteristic model of the slave robot model 20 including the object model 21 is Is asked for.

(,,) is a _{= (M + 0, B +} 0, K + 0) dynamic characteristics of the slave robot 30 to grasp the real object 31 relative to this _{(M + M 0, B +} B 0, K + K 0).

Forces or motion command values are equally transmitted to the dynamic characteristic models of the slave robot model 20 including the slave robot 30 and the object model 21 by the force applied to the master robot 10 by the operator 50.

At this time, the actual motion V _S of the hand of the slave robot 30 when it is in contact with or gripping the work target 31 is V _s = (d ² X _s / dt ² , dX _s / dt, X _s ). the motion model _S of the end of the slave robot model 20 the combined object model ^{_{21 s = (d 2 s /}} dt 2, d s / dt, s) and expressed, and the dynamic properties of the workpiece 31, the error between the dynamic characteristic model, the modeling error detection unit 40, is determined by e = ‖ _s -V _s ‖ norm like. The method of defining the norm depends on the work, but is defined as follows, for example.

‖ _S −V _s ‖ ＝ | d ² _s / dt ² −d ² X _m / dt ² | ＋ | d _s / dt −dX _m / dt | ＋ ｜ _s −X _m | Some upper limit for this norm Set e _lim .
This upper limit value indicates the allowable range of the error of the object model 21. The system controlling the slave robot 30 is
The norm e is constantly compared with the upper limit value e _lim . When this value is exceeded during work, that is, when e> e _lim , the modeling error determination unit 41 determines that the system has determined that the error of the dynamic characteristic model of the work object has deviated from the permissible range. Stop the operator
A warning is issued to the 50 by the display or voice. Receiving the warning, the operator 50 recognizes that the error of the target object model 21 becomes large, and again the slave robot 30
A command to create the object model 21 is issued to.

 The above operation flowchart is shown in FIG.

The present invention further includes a dynamic characteristic of the workpiece, the norm of the case of obtaining the error between the dynamic characteristics model; a e = ‖ _s -V _S ‖ set as follows. That is, ‖ _s -V _s ‖ _{^{= α | d 2 s / dt}} 2 -d 2 X s / dt 2 | + β | d s / dt-dX s / dt | + γ | s -X s | and defined.

The case of α = β = γ = 1 is the definition of norm. By multiplying the deviations of acceleration, velocity, and position by the weights α, β, and γ, respectively, the weight of the error of each component can be made different depending on the target work. For example, in the work in which the positional deviation is mainly emphasized, the values of α and β may be reduced and the value of γ may be increased. Also, these weightings can be added to the norm definition example.

A certain upper limit value e _lim is set for this norm, and the norm e
If this exceeds this value, e> e _lim The system will stop the slave robot, assuming that the error of the dynamic characteristic model of the work object has deviated from the allowable range,
The operator is also warned by the display or voice. The operator who receives the warning recognizes that the error of the object model has increased, and again issues a command to the slave robot to create the object model.

〔The invention's effect〕

According to the present invention, an error can be detected in the dynamic characteristic model of the work object in the master / slave robot, and a command to create the object model is issued based on this error, so that transmission delay and operation feeling Can be changed. Furthermore, by weighting the deviations of acceleration, speed, and position, it is possible to obtain a feeling of operation according to the importance of the work.

[Brief description of drawings]

FIG. 1 is a block diagram of a master / slave robot using a model, and FIG. 2 is an operation flowchart of a master / slave robot using a model.

Claims (1)

[Claims] 1. In a control method for a master / slave robot, when the hand of the slave robot contacts or grasps a work object, the actual movement V _S of the hand of the slave robot is V _S = (d ² X _s / dt ² , dX _s / dt, X _s ) where, d ² X _s / dt ² : acceleration of the slave robot's hand dX _s / dt: speed of the slave robot's hand X _s : the position of the slave robot's hand , The motion model _s of the hand of the slave robot is _s = (d ² _s / dt ² , d _s / dt, ₂ ) where d ² _s / dt ² : acceleration of the hand of the slave robot d _s / dt: of the slave robot Hand speed _s : Expressed as the position of the hand of the slave robot, the difference between the dynamic characteristics of the work object and its dynamic model e = ‖ _s −V _s ‖ is defined as the acceleration term, velocity term, and position term. norm ‖ _s were weighted to each -V _s ‖ _{^{= α | d 2 s / dt}} 2 -d 2 X s / dt 2 | _{β | d s / dt-dX} s / dt | + γ | s -X s | however, α, β, γ represents the weight coefficient (α + β + γ = 1 ), when this norm exceeds a predetermined reference value A method for controlling a master / slave robot, characterized in that the slave robot operation is stopped and an alarm is issued to prompt the operator to change the transmission delay or the operational feeling.