Dynamic External Force Feedback Loop Control of a Robot Manipulator Using a Neural Compensator—Application to the Trajectory Following in an Unknown Environment

Abstract

Force/position control strategies provide an effective framework to deal with tasks involving interaction with the environment. One of these strategies proposed in the literature is external force feedback loop control. It fully employs the available sensor measurements by operating the control action in a full dimensional space without using selection matrices. The performance of this control strategy is affected by uncertainties in both the robot dynamic model and environment stiffness. The purpose of this paper is to improve controller robustness by applying a neural network technique in order to compensate the effect of uncertainties in the robot model. We show that this control strategy is robust with respect to payload uncertainties, position and environment stiffness, and dry and viscous friction. Simulation results for a three degrees-of-freedom manipulator and various types of environments and trajectories show the effectiveness of the suggested approach compared with classical external force feedback loop structures.

Modified Position-Force Control for a Manipulator Geometrically Constrained by Round Obstacles

“…The type of environment and the degree of its familiarity largely determine the choice of the control algorithm. An approach in which the environment is well-known is shown, among others at work [4] and [10], while dealing with limited knowledge about the environment is presented in [6,7,11,17] and [16]. In this paper we assume that environment is well known.…”

Adaptive Position/Force Control of a Robotic Manipulator in Contact with a Flexible and Uncertain Environment

“…In the field of robotized mechanical processing [4,7,14], an important and topical issue is the development and implementation of a strategy for movement control, which could provide an appropriate quality of mechanical processing, despite the occurrence of phenomena that are not modelled, e.g., caused by significant errors in the description of the geometry of the processed component parts (connected with the uncertainty of their location regarding the robot) or local disturbances of their surface [20][21][22][23][24][25][26][27][28][29]. The present paper is concerned with the synthesis of movement control systems in the cases of disturbances of natural position constraints, which are the result of surface susceptibility and inaccuracies in its description.…”

Performance Optimization of Force Feedback Control System in Virtual Vascular Intervention Surgery

“…The loop-shaping method is used to improve performance and stability of force feedback, while nonlinearities can affect the behavior of the controller away from the nominal operating point [ 18 ]. Force/position control strategy is an effective way to help the operator to interact with the virtual environment, while it is also affected by the uncertainties of dynamical model and environment stiffness [ 19 , 20 ].…”