Benefits of over-actuation in motion systems

This paper studies the benefits of using additional actuators in the design of motion systems. The motion part and disturbance attenuation part require different placement of the actuators to work optimally, which is not possible in traditional designs. Allowing extra actuators in the design makes it possible to overcome this limitation. In this way the controllability of the internal dynamics of the structure can be both maximized for feedback and minimized for feedforward. By tuning a static relation between the actuators it is possible to minimize the excitation of resonances in the feedforward path. Feedback controller design is based on an existing vibration control strategy, which enables placement of the bandwidth beyond the lowest resonance frequencies. The idea is demonstrated by the example of a levitated beam.