Second order averaging methods for oscillatory control of underactuated mechanical systems

This paper considers the stabilization of underactuated mechanical systems via high-amplitude, high-frequency actuation. Using higher order averaging techniques, we extend previous work to the case where symmetric products of order higher than one are necessary for controllability. We first introduce a second order averaged mechanical system model that incorporates higher order terms. Using this result, we obtain trajectory tracking in the average by feeding back an error signal that is constant over whole periods of the oscillatory actuation. A simulation demonstrates the method.