Design Method for Robust Compliant Motion for Manipulators

Kazerooni, H.; Houpt, Paul; Sheridan, Thomas B.

doi:10.23919/acc.1986.4789234

Cited by 18 publications

(20 citation statements)

References 8 publications

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“…Substituting (19) with (20) and (21) in (18) yields mdL1x+kDL1x+kpL1x+kFL1f+klltL1fdcJ = 0 (22) 81 which reveals that, thanks to the integral action, L1f is allowed to prevail over L1x at steady state.…”

Section: Inverse Dynamicsmentioning

confidence: 99%

“…Assuming that the desired force is aligned with the normal to the contact plane and contact is not lost, the stability analysis of the system (1) under the inverse dynamics parallel control (17), (19), (20) and (21) with the environment (14) and (16) can be developed according to c1assicallinear systems theory. In detail, plugging (14) in (22) gives…”

Section: Inverse Dynamicsmentioning

confidence: 99%

“…To the first category belong compliance (or stiffness) control [31, 33] and impedance control schemes [18,20], where the position error is related to the contact force through a mechanical stiffness or impedance of adjustable parameters. A robot manipulator under impedance control is described by an equivalent mass-spring-damper system with the contact force as input.…”

Section: State-of-artmentioning

confidence: 99%

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Parallel Force/Position Control of Robot Manipulators

Siciliano

1996

Robotics Research

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This paper is aimed at presenting a survey on a class of parallel force/position control schemes which have been proposed in the latest five years by the author and co-workers. Several control schemes have been devised under this framework for the case of contact with a compliant planar surface. A common feature of such schemes is that, at the equilibrium, the force can be shown to be regulated to a desired constant value at the expense of a position error which depends on environment stiffness. If tracking of end-effector position along the unconstrained task space directions is desired, a passivity-based control scheme can be used which can be naturally made adaptive with respect to manipulator dynamic parameters. On the other hand, if only regulation of position is desired, a simple PID control can be used which can be made adaptive as well in the case of imperfect gravity compensation, and can even avoid velocity measurements. State-of-ArtControl of interaction between a robot manipulator and the environment is crucial for successful execution of a number of practical tasks where the robot's end effector has to manipulate an object or perform some operation on a surface. The specific feature of robot tasks such as polishing, deburring, or assembly, demands control also of the exchanged forces at the contact. The contact force is thus the quantity describing the state of interaction in the most complete fashion, and the interaction control problem [47] has attracted a wide number of researchers in the last decade.Interaction control strategies can be grouped in two categories; those performing open-loop jorce control and those performing direct closed-loop jorce control. The main difference between the two categories is that the former achieve indirect force control via closed-loop position control, without explicit closure of a force feedback loop; the latter, instead, offer the possibility of controlling the contact force to a desired value, thanks to the closure of a force feedback loop.To the first category belong compliance (or stiffness) control [31, 33] and impedance control schemes [18,20], where the position error is related to the contact force through a mechanical stiffness or impedance of adjustable parameters. A robot manipulator under impedance control is described by an equivalent mass-spring-damper system with the contact force as input. The resulting impedance may be linear or nonlinear, depending on the fact whether force feedback is used or not.The most common strategy belonging to the second category is the hybrid position/jorce control which aims at controlling position along the unconstrained task space directions and force along the constrained task space directions. A selection matrix acting on both desired and feedback quantities serves this purpose for typically planar contact surfaces [32], whereas the explicit constraint equations have to be taken into account for general curved contact surfaces [50,25,26,14, 2,49].An alternative strategy still in the second category is the...

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Section: Inverse Dynamicsmentioning

confidence: 99%

Section: Inverse Dynamicsmentioning

confidence: 99%

Section: State-of-artmentioning

confidence: 99%

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Parallel Force/Position Control of Robot Manipulators

Siciliano

1996

Robotics Research

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“…Compliant motion and force control are still active research areas and such works as [16,21,24,29,30,25] provide ample basis on which this controller is built. If complete joint space reference trajectories are provided to the controller, most of the control theory for active compliance applies to the current problem.…”

Section: Introductionmentioning

confidence: 99%

Localization of hybrid controllers for manipulation on unknown constraints

Bay

Hemami

1993

J Intell Robot Syst

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A robotic control problem is proposed in which a six degree of freedom manipulator is to explore the surface of an object which is a priori unknown to the controller. Choice of an exploration strategy is discussed. The exploration strategy developed uses the maximal freedom of choice allowed under the restrictions of the problem. In particular, it is shown that any admissible reference trajectory can be used, provided it lies in a two-dimensional manifold which maps continuously into the surface. The inverse kinematic velocity problem is then solved using pseudo-inverses which fully exploit the redundancy of the system. The controller used as an example uses computed torque for linearization and compliant motion theory for movement along the desired path. The solution to the inverse kinematic problem together with the on-line generation of 'selection-mappings' constitute a hybrid force/velocity controller. Successful exploration is shown to depend heavily on reliable force control, so PI force feedback is also proposed. Simulation and experimental results demonstrate the effectiveness of the overall design.

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“…The stiffness and mass components in the impedance model is selected to match the desired stiffness and the cutoff frequency of the controller [8]. This method is very simple but highly efficient to regulate the impact transition.…”

Section: Impedance Modulationmentioning

confidence: 99%