A novel RISE-based adaptive feedforward controller for redundantly actuated parallel manipulators

• Published in: 2014 IEEE/RSJ International Conference on Intelligent Robots and Systems pp. 2389 - 2394
• Main Authors: Bennehar, M., Chemori, A., Pierrot, F.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.09.2014
• Subjects: Adaptation models; Feedforward neural networks; Joints; Manipulators; Robot kinematics; Uncertainty
• ISSN: 2153-0858; 2153-0866
• DOI: 10.1109/IROS.2014.6942886

A novel adaptive controller based on the Robust Integral of the Sign of the Error (RISE) is proposed. The RISE feedback strategy yields semi-global asymptotic tracking despite the presence of unstructured additive disturbances provided some limited assumptions on the system. To achieve better tracking performance, the RISE controller is extended with a model-based adaptive feedforward term. The addition of the feedforward term compensates for the structured uncertainties yielding reduced tracking errors and reduced control effort. The proposed controller is experimentally implemented on a 3-DOFs redundantly actuated parallel manipulator. The computed control inputs are projected using a kinematics based projector in order to remove the internal efforts that may damage the mechanical structure of the manipulator. Experimental results show a better performance of the proposed adaptive controller compared to the basic RISE controller in terms of tracking accuracy and energy consumption.