ACTIVE VIBRATION ABSORBER FOR THE CSI EVOLUTIONARY MODEL - DESIGN AND EXPERIMENTAL RESULTS

The development of control technology for large flexible structures must include practical demonstrations to aid in the understanding of controlled structures in space. To support this effort, a testbed facility has been developed to study practical implementation of new control technologies. The paper discusses the design of a second-order acceleration feedback controller that acts as an active vibration absorber. This controller provides guaranteed stability margins for collocated accelerometer/actuator pairs in the absence of accelerometer/actuator dynamics and computational time delay. Experimental results in the presence of these factors are presented and discussed. The primary performance objective considered is damping augmentation of the first nine structural modes. Comparison of experimental and predicted closed-loop damping is presented, including test and simulated-time histories for open- and closed-loop cases. Although the simulation and test results are not in full agreement, robustness of this design under model uncertainly is demonstrated. The basic advantage of this second-order controller design is that the stability of the controller is model-independent for collocated accelerometers and actuators.