Extended Model-Based Feedforward Compensation in ℒ1 Adaptive Control for Mechanical Manipulators: Design and Experiments

Abstract

This paper deals with a new control scheme for parallel kinematic manipulators (PKMs) based on the L 1 adaptive control theory. The original L 1 adaptive controller is extended by including an adaptive loop based on the dynamics of the PKM. The additional modelbased term is in charge of the compensation of the modeled non-linear dynamics in the aim of improving the tracking performance. Moreover, the proposed controller is enhanced to reduce the internal forces, which may appear in the case of redundantly actuated PKMs (RA-PKMs). The generated control inputs are first regulated through a projection mechanism that reduces the antagonistic internal forces, before being applied to the manipulator. To validate the proposed controller and to show its effectiveness, realtime experiments are conducted on a new four degrees-of-freedom (4-DOFs) RA-PKM developed in our laboratory.

A Redundant Parallel Robotic Machining Tool: Design, Control and Real-Time Experiments

“…Several control techniques have been proposed and studied in the literature starting from the non-model-based non-adaptive and adaptive controllers, ending up with model-based non-adaptive and adaptive controllers. One can mention few examples from the aforementioned classes of control implemented on PKMs respectively: Proportional-Integral-Derivative (PID) [29,18], nonlinear PID [25], Augmented PD (APD) [28], Adaptive Feedforward plus PD [2,17], Desired Compensation Adaptive Control Law (DCAL) [12], Adaptive controller based on the Robust Integral of the Sign of the Error (RISE) [13], Feedforward Compensation in L1 Adaptive Control [14]. This chapter introduces a five-degree-of-freedom redundantly actuated PKM named ARROW 1 characterized by the good compromise between rapidity and precision developed for machining tasks.…”

L 1 Adaptive Fractional Control Optimized by Genetic Algorithms with Application to Polyarticulated Robotic Systems

“…Among the drawbacks of the L 1 adaptive control is the time lag. Researchers in [13][14][15] have proposed to add different supplementary controllers aiming to eliminate the appearing time lag. In this paper, the proposed contribution is the L 1 adaptive fractional control based on fractional calculus [16][17][18][19].…”

A Novel Model-Based Robust Super-Twisting Sliding Mode Control of PKMs: Design and Real-Time Experiments

“…The proposed control structure formed by a dynamic feedforward term, a feedback supertwisting term, and a stabilizing feedback term, can be more adequate for real-time implementations. Moreover, this control scheme can be easily applied to the general class of robotic manipulators whose dynamics is described by (4).…”