Discrete-Time Nonlinear Damping Backstepping Control With Observers for Rejection of Low and High Frequency Disturbances

A discrete-time backstepping control algorithm is proposed for reference tracking of sys- tems affected by both broadband disturbances at low frequencies and narrow band distur- bances at high frequencies. A discrete time DOB, which is constructed based on infinite impulse response filters is applied to compensate for narrow band disturbances at high fre- quencies. A discrete-time nonlinear damping backstepping controller with an augmented observer is proposed to track the desired output and to compensate for low frequency broadband disturbances along with a disturbance observer, for rejecting narrow band high frequency disturbances. This combination has the merit of simultaneously compensating both broadband disturbances at low frequencies and narrow band disturbances at high fre- quencies. The performance of the proposed method is validated via experiments.

Journal article