Modeling and Control of a Flexible Structure Incorporating Inertial Slip-Stick Actuators

Shapeandvibrationcontrol of a linear  exible structure bymeans of a new type of inertial slip-stick actuator are investigated. A nonlinear model representing the interaction between the structure and a six-degree-of-freedom Stewart platform system containing six actuators is derived, and closed-loop stability and performance of the controlled systems are investigated. A linearized model is also derived for design purposes. Quasistatic alignment of a payloadattached to the platformis solved simplybyusing a proportionalcontroller based on a linear kinematic model. The stability of this controller is examined using a dynamicmodel of the complete system and is validated experimentally by introducing random thermal elongations of several structural members. Vibration control is solved using an H 1 loop-shaping controller and, although its performance is found to be less satisfactory than desired, the nonlinearmodel gives good predictions of the performance and stability of the closed-loop system.