An Improved Fractional-Order Reset Active Disturbance Rejection Control Scheme for Plants with a Fractional Pole

Abstract

Reset control is known to overcome fundamental limitations of linear time-invariant systems by breaking the trade-off between transient speed and overshoot. However, when the plant exhibits fractional-order dynamics, conventional reset approaches fail, as the plant’s non-local memory is not erased by resetting the controller state, and persistent post-reset oscillations are thereby induced. In this paper, the structural mismatch responsible for this failure is first identified. To address it, an improved fractional-order reset active disturbance rejection control strategy is proposed. A dedicated post-reset state assignment is introduced, by which the residual historical excitation driving the oscillations is actively compensated, and the closed-loop stability is analyzed separately under the flow dynamics and the jump dynamics. Simulations are conducted on a fractional-order electromagnetic model of a permanent magnet synchronous motor, through which the elimination of oscillations observed with conventional fractional-order reset integrators is confirmed, and an overshoot-free transient response with strong robustness against parameter mismatches is demonstrated.