Adaptive Fuzzy Control of Stewart Platform under Actuator Saturation
A novel adaptive fuzzy trajectory tracking algorithm of Stewart platform based motion platform is proposed to compensate path deviation and degradation of controller-s performance due to actuator torque limit. The algorithm can be divided into two parts: the real-time trajectory shaping part and the joint space adaptive fuzzy controller part. For a reference trajectory in task space whenever any of the actuators is saturated, the desired acceleration of the reference trajectory is modified on-line by using dynamic model of motion platform. Meanwhile an additional action with respect to the difference between the nominal and modified trajectories is utilized in the non-saturated region of actuators to reduce the path error. Using modified trajectory as input, the joint space controller incorporates compute torque controller, leg velocity observer and fuzzy disturbance observer with saturation compensation. It can ensure stability and tracking performance of controller in present of external disturbance and position only measurement. Simulation results verify the effectiveness of proposed control scheme.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1079532Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1621
 J. P. Merlet, Parallel Robots (2nd), Berlin: Springer, 2006.
 D. Bernstein and A. Michel, "A chronological bibliography on saturating actuators" International Journal of Robust and Nonlinear Control, vol. 5, no.5, pp. 375-380, 1995.
 E. N. Johnson and A. J. Calise, "Neural network adaptive control of systems with input saturation", Proceedings of IEEE American Control Conference, pp. 3527-3532, 2001.
 K. Ohishi, K. Akahori, W. Kaewprom and et al, "Robust manipulator control method considering limit values of torque and controller output", Proceedings of the IEEE IECON 22nd International Conference, pp. 1252-1257, 1996.
 M. V. Kothare, P. J. Campo, M. Morari and et al, "A unified framework for the study of anti-windup designs" Automatica, vol. 30, no. 12, pp.1869-1883, 1994.
 Y. I. Lee and B. Kouvaritakis, "Receding horizon output feedback control for linear systems with input saturation" Proceedings of the 39th IEEE Conference on Decision and Control, pp. 656-661, 2000.
 K. Ohnishi, "A new servo method in mechatronics" Trans. Japanese Society of Electrical Engineering, vol. 107-D, pp. 83-6, 1987.
 E. Kim, "A fuzzy disturbance observer and its application to control" IEEE Trans. on Fuzzy Systems, vol. 10, no. 1, pp. 77-82, 2002.
 L. X. Wang and J. M. Mendel, "Fuzzy basis functions, universal approximation, and orthogonal least-squares learning" IEEE Trans. on Neural Networks, vol. 3, no. 5, pp. 807-814, 1992.
 S. Nicosia and P. Tomei, "Robot control by using only joint position measurements" IEEE Trans on Automatic Control, vol. 35, no. 9, pp. 1058-1061, 1990.
 M. J. Corless and G. Leitmann, "Continuous state feedback guaranteeing uniform ultimate boundedness for uncertain dynamic systems" IEEE Trans on Automatic Control, vol. AC-26, no. 5, pp. 1139-1144, 1981.