JPH0780139B2 - Master-slave manipulator - Google Patents

Description

Detailed Description of the Invention a. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manipulator used in various industrial fields for remote control using a plurality of arms, and relates to a coordinated control device for a master manipulator and a plurality of slave manipulators. .

(Prior Art) In remote manipulation, a human operates a master arm or an operation lever (hereinafter referred to as a master arm),
It is realized by operating the slave arm in accordance with the operation.

Conventionally, many manipulation devices are configured so that the posture of one master arm operated by an operator is made to follow the posture of one slave arm. In addition, a worker usually controls the movement of one slave arm by using a TV camera and a TV display for monitoring the posture and work status of the slave arm.

If the weight or size of the work target is too large,
I needed a big slave arm.

(Problems to be solved by the invention) Therefore, in such an operation configuration at present, since a person indirectly moves the slave arm to a position away from the master arm, the work is difficult and the operation is complicated. ,
It had the drawback of being complicated. For example, a skilled operator is required to realize the subtle movement of the slave arm. Also,
It was necessary to feed back the force difference of the disturbance applied to the slave arm to the master arm. Therefore, there is a drawback that the control system becomes unstable.

Further, it becomes difficult for one slave arm to perform an operation while applying an external force to the work object and at the same time maintaining an internal force. On the other hand, if two or more slave arms were operated, it was difficult to realize a high degree of cooperative operation such as control of the force acting on the work object. An object of the present invention is to provide a novel master-slave manipulator that realizes a system in which an operator can concentrate only on the operation of an object in such a case and a system that automatically performs the possible work.

B. Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, a master-slave manipulator according to the present invention uses a command from a master arm as a motion command of a target object of a slave arm to perform a plurality of target motions. In a master-slave manipulator system that controls slave arms in cooperation with each other, a master arm, a plurality of slave arms, and inputs from the master arm are command values according to work such as position, speed, and internal force of a work object. A selection unit, a unit that applies the internal force to be held to the work target to the selection unit, and a calculation unit that calculates positions, velocities, and accelerations of the plurality of slave arms based on a command from the selection unit, A servo control unit that controls the plurality of slave arms using an output from the arithmetic unit as a command value, and a servo control unit that is added to each of the slave arms. A force sensor that detects force and torque and outputs the force and torque to the calculation unit, and the position and speed of the plurality of slave arms that take the force and torque detected by the force sensor as inputs and that correspond to the inputs. , A virtual mechanical model computing unit that computes according to a predetermined virtual mechanical model so as to output acceleration, and is provided by a master-slave manipulator.

Further, in the master-slave manipulator of the present invention, when the target trajectories of the plurality of slave arms, the force and the moment to be generated are input, the deviation to be generated by each slave arm due to the input from the force sensor is detected. It is more effectively provided by the master-slave manipulator, wherein the virtual-dynamics model computing unit takes a new target trajectory when it occurs.

(Operation) In the master-slave manipulator of the present invention, the force and torque applied to the plurality of slave arms are detected by the force sensor and input to the virtual dynamic model calculation unit. The characteristic of the slave arm with respect to the mechanical quantity is stored in advance in the virtual dynamic model calculation unit (data of virtual mass, virtual viscosity, and virtual spring constant is stored in a database), and is input to the calculation unit according to the characteristic. The master-slave manipulator is controlled by calculating the position, velocity, and acceleration most suitable for the given work according to the sense of force and giving them to the servo controller.

(Example) The master-slave manipulator of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

The master arm 1 is operated by the operator via the servo control unit 2, and a motion command of the work target 12 is input to the motion, force and torque calculation unit 3. Here, the motion command from the master arm 1 is selected as a position command or a speed command. At the same time, the internal force 13 to be held by the work object 12 is also input. Based on this input, the motion / force / torque calculation unit 3 determines the positions, velocities, and accelerations of the two slave arms 6 and 10 and the work object 12.
The force to be applied to is output to the virtual dynamic model calculation units 4 and 8 of the slave arms 6 and 10, respectively. The virtual mechanical model computing units 4 and 8 receive the force and torque signals from the force detectors 7 and 11, respectively, as input to the two slave arms 6, and
The position, velocity, and acceleration of 10 are calculated and output to the servo control units 5 and 9.

This force sense detector is, so to speak, a sense of force in terms of robot operation, and the detector detects a force acting on the slave arm or the like.
Also in the present invention, forces and torques in each axial direction in a plurality of dimensions are detected. For example, a strain gauge or the like is used to detect the force acting on each of the three-dimensional directions, and is installed at a plurality of positions suitable for detecting each component force.

Further, the servo control units 5 and 9 realize the motion control of the slave arms 6 and 10 based on this input and the signals from the position, speed and acceleration detectors of the slave arms 6 and 10. In these controls, coordinate conversion is generally important in position control. It can be divided into position control that focuses on the position during exercise and route control that focuses on the movement route. Further, speed control is an important control item because of high speed, small difference between command speed and actual speed, and high speed accuracy during repetition. Acceleration control is necessary for smooth start and stop of robot control. Force control is required in order to realize an accurate work with respect to the force and torque applied to the work target, and is widely used for polishing, assembly and the like.

In response to the above control items, the servo control units 5 and 9 realize motion control of the slave arms 6 and 10.

Next, a dynamic model of the object and the slave arm will be described.

To realize coordinated control of multiple slave arms,
It is necessary to convert the position and velocity of the object given by the master arm into the motion of each slave arm, and further decompose the force to be applied to the object such as internal force into the force generated by each slave arm. So below,
Each position and vector will be defined and explained.

r ₀ : Position vector of the center of gravity of the object viewed from the absolute coordinate system v ₀ : Velocity vector of the center of gravity of the object w ₀ : Angular velocity vector of the center of gravity of the object r ₁ : Position vector p ₁ : Position vector of the tip of the slave arm i as seen from the coordinate system of the target object _IN : N × N unit matrix g: Gravity acceleration vector To explain this relationship in Fig. A mechanical relationship diagram is shown.

Consider a case where a plurality of slave arms hold one object that can be regarded as a rigid body. It is assumed that the i-th slave arm force f _i and the moment n _i are applied to the object at contact points O ₁ and O ₂ with the object. At this time, the force F _i and moment N _i applied to the center of gravity of the object are equivalently F _i = f _i (1) N _i = n _i + p _i × f _i (2) Therefore, the equation of motion of the object is described as follows.

m _{0 0} = F ₀ + m ₀ g (3) M _{0 0} + w ₀ × (M ₀ w ₀ ) = N ₀ (4) However, F ₀ = F ₁ + F ₂ (5) N ₀ = N ₁ + N ₂ (6) Rewriting equations (3) and (4) ... L = K · F (7) K = [I ₆ , I ₆ ] (9) F = [F ₁ ^T , N ₁ ^T , F ₂ ^T , N ₂ ^T ] (10) From the motion command of the object given from the master arm, When L is calculated and Equation (7) is solved for F, F = K ⁺ L + (I ₁₂ −K ⁺ K) · A (11).

However, K ⁺ is a pseudo inverse matrix of the matrix K, and A is an arbitrary 12-dimensional vector.

Here, the second term on the right side of the equation (11) corresponds to the internal force applied to the object.

If the motion of the target object is given by the master arm and the desired internal force to be applied to the target object is set, F from Equation (11)
Can be calculated.

Therefore, the forces and moments that the slave arm should generate with respect to the object are as follows: f _i = F _i (12) n _i = N _i −p _i × F _i (13).

Next, the virtual dynamic model will be described.

When the target trajectory Xd _i of the slave arm and the force and moment fd _i to be generated are input, the target trajectory should be executed by the input f _i from the force sensor (force sensor) attached to the tip of the slave arm. It is modified by ΔX _{i of} the dynamic model selected to fit the task.

_{Mm i · Δ i + Dm i} · Δ i + Km i · ΔX i = f i -fd i ···· (14) _{wherein, ··· um i = d-Mm} i -1 · Dm i · Δ i - Mm _i ^-1・ Km _i・ ΔX _i ＋ Mm _i ^-1・ (f _i −Fd _i ) (15) The new target trajectory Xm _i is ... This equation (16) represents the virtual mechanical model of the slave arm.

FIG. 3 is a block diagram showing a configuration example of the virtual dynamics model computing unit of the present invention.

The virtual mechanical model is composed of a virtual mass Mm, a virtual viscosity Dm, and a virtual spring constant Km, and the target value xd of the slave arm receives feedback of the force and the moment f detected by the force sensor, and is given by the formula (14). Subject to modification by the dynamic model ΔX shown.

This is the mass Mm, the viscosity coefficient Dm, and the external force (f-fd).
It is expressed as the behavior of the mechanical system consisting of the spring constant Km.

By controlling the slave arm according to such a model, the operator is relieved from paying attention to the internal force and external force of the object. Further, the model used for the series of operations is selected from a database that is stored in advance (data of virtual mass, virtual viscosity, and virtual spring constant is stored in a database) based on the input from the sensor. That is, the virtual mass Mm, the virtual viscosity Dm, and the virtual spring constant Km are concretely given to the virtual dynamics model calculation unit described above.

C. EFFECTS OF THE INVENTION Since the present invention is configured as described above, complicated work can be performed by using a plurality of slave arms.
In addition, the operator is relieved of paying attention to the plurality of slave arms, and it suffices to focus on the object and operate the master arm.

By using the virtual mechanics model as an intelligent auxiliary means, a series of operations can be performed while maintaining the state of the target object, which has the effect of reducing the labor of the operator. In addition, when the object interferes with the external environment, it has an effect of suppressing impact.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a principle diagram of the operation of a slave arm, and FIG. 3 is a block diagram showing a configuration example of a virtual mechanical model computing unit of the present invention. 1: Master arm, 2: Servo control unit 3: Motion, force, torque calculation unit 4, 8: Virtual dynamic model calculation unit 5, 9: Servo control unit 6, 10: Slave arm, 7, 11: Force sensor , 12: Work object 13: Internal force that work object should hold

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazuhiro Kosuge United States 02140 Cambridge, Massachusetts # 7 Abe. Cogswell 11 (72) Inventor Jun Ishikawa 6-15-13 Arima, Miyamae-ku, Kawasaki-shi, Kanagawa (56) References JP-A-63-34609 (JP, A) JP-A-62-297080 (JP, A)

Claims (2)

[Claims] 1. A master-slave manipulator system in which a command from a master arm is used as a motion command for an object of a slave arm to control the motion of the object in cooperation with a plurality of slave arms, wherein a master arm and a plurality of slave arms are provided. A selection unit that uses the input from the master arm as a command value according to the work such as the position, speed, and internal force of the work target; and a unit that adds the internal force to be held by the work target to the selection unit. A computing unit that calculates the positions, velocities, and accelerations of the plurality of slave arms based on a command from the selecting unit; and a servo control unit that controls the plurality of slave arms using the output from the computing unit as a command value. A force sensor that detects the force and torque applied to each slave arm and outputs the force and torque to the computing unit; and the force sensor detected by the force sensor. And a virtual dynamics model calculation unit that calculates a torque according to a predetermined virtual dynamics model that outputs the positions, velocities, and accelerations of the slave arms according to the inputs. Characteristic master-slave manipulator. 2. Target trajectories of said plurality of slave arms,
When a force and a moment to be generated are input, the virtual dynamic model calculation unit takes a new target trajectory when a deviation to be generated by each slave arm occurs due to the input from the force sensor. The master-slave manipulator according to claim 1.