The last decade has seen the advent of active aperture antennas and other large distributed parameter systems. These antennas have the capability to change their shape to resemble a desired radiation pattern. In this study a method to simultaneously achieve active shape and vibration control of distributed parameter systems is presented. The optimal actuator location is computed for a desired profile using non-linear optimal programming techniques. For most shape control applications the actuator and sensor dynamics are much faster than the structural dynamics and slow shape changes are sufficient, thus quasi-static analysis is sufficient. The quasi-static actuation forces for the desired profile are then calculated by using independent modal space control (IMSC) principles. Quasi-static shape control is then implemented in a closed loop control using a 3-D photogrammetry sensing system. A sliding mode controller is designed for each dominant mode such that it drives the error between the required and actual modal contribution to zero. Conventional sliding mode controllers are discontinuous in nature and they might cause “control spillover”. This is avoided by using an “observer-based” solution.

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