Robust tracking control for a class of electrically driven flexible-joint robots without velocity measurements

• Published in: International journal of control Vol. 85; no. 2; pp. 194 - 212
• Main Authors: Chang, Yeong-Chan, Yen, Hui-Min
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 01.02.2012; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Adaptative systems; Applied sciences; Computer science; control theory; systems; Control system analysis; Control systems; Control theory; Control theory. Systems; Dynamical systems; Dynamics; electrically driven; Exact sciences and technology; Feedback; flexible-joint robot; Modelling and identification; observer-based controller; Observers; Robotics; Robots; robust tracking control; Studies; Tracking control; Disturbance rejection; dynamic control; Feedback regulation; flexible-joint robot; Robotics; Servomotor; Time varying system; Linear time invariant system; Uncertain system; Linkage mechanism; Observer; Reduced order systems; System identification; Electric motor; Dc motor; observer-based controller; Compliant mechanism; Set point; Motion estimation; Measurement sensor; Tracking task; electrically driven; Electric control; Robust control; Position measurement; robust tracking control; Motion control; Output feedback
• ISSN: 0020-7179; 1366-5820
• DOI: 10.1080/00207179.2011.643241

This article addresses the motion tracking control for a class of flexible-joint robotic manipulators actuated by brushed direct current motors. This class of electrically driven flexible-joint robots is perturbed by time-varying parametric uncertainties and external disturbances. A novel observer-based robust dynamic feedback tracking controller without velocity measurements will be developed such that the resulting closed-loop system is locally stable, all the states and signals are bounded and the trajectory tracking errors can be made as small as possible. Only the measurements of link position and armature current are required for feedback and so the number of sensors in the practical implementation of the developed control scheme can be greatly reduced. The observer structure is of reduced order in the sense that the observer is constructed only to estimate the velocity signals and whose dimension is half of the dimension of flexible-joint robots. Especially, for the set-point regulation problem, the developed controller is simplified to a linear time-invariant controller. Consequently, the robust tracking control scheme developed in this study can be extended to handle a broader class of uncertain electrically driven flexible-joint robots and the developed robust control schemes possess the properties of computational simplicity and easy implementation. Finally, simulation results are presented to demonstrate the effectiveness of the proposed control algorithms.