Abstract
In this paper we present a hybrid Sliding Mode Control (SMC) and Constant Amplitude Feedback Control (CAFC) architecture for slewing flexible structures. The SMC controller is used to servo the flexible structure and the CAFC is used to suppress residual vibrations of the flexible structure. A single-axis encoder/DC motor/harmonic drive assembly is used for large angle slewing. A graphite/epoxy composite structure with embedded strain sensors/actuators is used for active vibration suppression. The results of this study include the analytical dynamic and control system development with experimental verification. The hybrid control algorithm uses the output sensor data from the encoder and strain sensor along with filters to derive velocity information to compute the control effort for the motor and strain actuators. Near-minimum time maneuvers based on an equivalent rigid structure are used to slew the flexible active structure. The tip mass was varied to evaluate control system robustness. Experimental slewing studies were performed to compare the benefits of using active rather than passive structures. For the active case the experimental results showed a reduction in residual vibration and settling time.
