A comparison study of nonlinear control techniques for the RTAC system

In this paper, we implement the recently developed energy- and entropy-based hybrid control framework for stabilization of Lagrangian systems on the experimental testbed of the Rotational/Translational Proof-Mass Actuator (RTAC) system. In addition, on the same experimental platform, we implement the sliding mode control framework for stabilization of underactuated dynamical systems and compare the performances of all three controllers. The concept of an energy-based hybrid controller involves a hybrid controller that exploits the feature that the states of the dynamic controller may be reset to enhance the overall energy dissipation in the closed-loop system. We give a detailed description of the hardware layout for the testbed and present the experimental results. The real-time data indicate that the energy- and entropy-based hybrid controllers result in almost the same closed-loop system behavior with the same control effort. However, hybrid controllers use significantly less control effort and stabilize the system in a shorter period of time than the sliding mode controller. (C) 2009 Elsevier Ltd. All rights reserved.