JP3163609B2 - Manipulator cooperative control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooperative control device for manipulators that grips an object with a plurality of manipulators using an impedance model.

[0002]

2. Description of the Related Art Impedance control of a manipulator is performed by inputting a force (including torque) acting between the manipulator and an object and outputting an impedance model (also referred to as a virtual dynamic model) that outputs the position (or angle) of the manipulator. It is set and controlled based on the output. Therefore, in a system having a plurality of manipulators, an impedance model is required by the number of manipulators. According to this control method, even when the shape of the target object cannot be accurately grasped in the steady state, the grasping state can be maintained by a plurality of manipulators. However, if an unexpected force (disturbance) is applied from the outside while holding the object, a soft impedance must be set to prevent excessive force from being applied to the object or the outside. No. In such a case, each manipulator individually reacts with a soft impedance, and the object cannot be grasped and may be dropped.

[0003]

When impedance control is performed independently for each manipulator as described above, a soft impedance is used to prevent an excessive force from being applied to a grasped object or the external world against disturbance. However, there is a problem that it is difficult to maintain the gripping state. An object of the present invention is to prevent an excessive force from acting on a gripped object or the outside world without dropping the gripped object when gripping the object with a manipulator that performs a plurality of impedance controls. is there.

[0004]

Means for Solving the Problems The present invention, each Manipyure
From the force acting between the data and the object,
Find the internal force to balance and use the impedance of each manipulator.
The internal force is used as an input to the model. In addition, each mani
Rotate the object and the resultant force acting between the purator and the object
Trajectory correction amount for determining the rotational force to be applied, and having a resultant force impedance model part and a rotational impedance model part for the resultant force and the rotational force , respectively, and distributing the trajectory correction amount obtained by these to the target trajectory of each manipulator. And a distribution unit.

[0005]

[Function] An object is maintained by applying an internal force to the input of the impedance model of each manipulator, the impedance model for the resultant force and the rotational force is set, and the trajectory correction amount obtained by these is set to the target trajectory of each manipulator. By distributing, it is possible to control such that an excessive force is not applied to the outside world.

[0006]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing an embodiment of the present invention, in which two manipulators are controlled. Manipulators 1a, 1b
Are respectively controlled by the motion control units 2a and 2b, and the motion control units 2a and 2b
Control is performed so that the actual trajectory follows a and rb. The forces exerted by the manipulators from the outside world are determined by the force detection devices 3a, 3
b and is input to the force decomposition unit 4. The force input to the force decomposition unit includes an internal force 5a, 5b exerted on each object by each manipulator, a resultant force 6 acting from the outside, and a rotational force 7
Is decomposed into The internal forces 5a and 5b are input to the impedance model units 8a and 8b of each manipulator to obtain a trajectory correction amount. The resultant force 6 and the rotational force 7 are input to the resultant impedance unit 9 and the rotational impedance unit 10, respectively, to obtain an object trajectory correction amount. The obtained object trajectory correction amount is distributed by the trajectory distribution unit 11 to the target trajectory of each manipulator. The decomposition of the force when the object is gripped by the two manipulators is obtained by the following equation, assuming that each contact state is a point contact and only the translational component of the force is given at the contact point (no moment is given). Synthetic force: F ₀ = f ₁ + f ₂ Rotational force: M ₀ = r ₁ × f ₁ + r ₂ × f ₂ Internal force: _Fi = f ₁ · (r ₁ -r ₂ ) / (| r ₁ -r
₂ |) + f ₂ · (r ₂ −r ₁ ) / (| r ₁ −r ₂ |) (where f ₁ and f ₂ are force vectors applied to each contact point,
r ₁ and r ₂ are vectors from the center of rotation to each contact point, ×
Is the outer product, and is the inner product.) At the two contact points, the force component in the direction toward the other contact point is extracted, and two opposing forces are obtained. The smaller of the absolute values is determined between the two points. In some cases. The object gripping by two manipulators has been described above, but this can be easily extended to three or more manipulators.

[0007]

As described above, according to the present invention, when an object is gripped by a plurality of manipulators, the impedance with respect to the internal force for gripping the object and the impedance for flexibly responding to the external force are adjusted. Since the setting can be performed separately, an operation of dropping the object, preventing excessive force from being applied to the object and the outside world, and keeping the object safe can be easily realized.

[Brief description of the drawings]

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

[Explanation of symbols]

 1a, 1a Manipulator 2a, 2b Motion control unit 3a, 3b Force detection unit 4 Force decomposition unit 5a, 5b Internal force 6 resultant force 7 rotational force 8a, 8b impedance model unit 9 resultant impedance unit 10 rotational impedance unit 11 orbital distribution unit ra, rb Target trajectory

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-177566 (JP, A) JP-A-1-316188 (JP, A) JP-A-3-67309 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B25J 9/10 B25J 13/08

Claims (1)

(57) [Claims] A force acting between an object and each manipulator
Equipped with a force detecting device for detecting each of the manipulators
Along with the force detection value obtained by the force detection device and an impedance model unit for each of the manipulators representing the relationship between the positions of the manipulators, the cooperative impedance of a manipulator that grips one object with a plurality of manipulators In the control device, each of the manipulators is obtained from the force detection value of each of the manipulators.
Of the forces acting between the rotator and the object
The total force that is the sum of the internal force balanced inside
And acts on the rotation center of the object to move the object
Translational force and rotation of the object around the center of rotation
Inputting the internal force;
An impedance model part for each manipulator;
A resultant impedance model for inputting the resultant force,
A rotational impedance model unit for inputting a rolling force, and a trajectory correction amount obtained from a trajectory correction amount obtained from the rotational impedance model unit and the resultant force impedance model unit, to each target command obtained from the impedance model unit for each of the manipulators. A cooperative control device for a manipulator, comprising: a trajectory correction amount distribution unit that distributes and corrects.