Mechanical resonance suppression and disturbance rejection of two-mass system based on state-feedback observer

High stiffness control in servo system can effectively suppress the dynamic disturbance phenomenon by load variation.Based on the motor model, state-feedback observer can provide the load information quickly and accurately for disturbance rejection.But strong disturbance rejection ability will cause mechanical resonance phenomenon with the finite elasticity of the connecting device easily.To solve this problem, the contradiction between anti-resonance and anti-disturbance is studied.On the basis of keeping disturbance rejection ability, a control algorithm is adopted in this paper based on state-feedback observer.It use fractional order disturbance observer(FO-DOB) to build the state-feedback observer up, which can suppress speed and torque fluctuation caused by the mechanical resonance.Fractional order filter will maximize the extent of the filter selection range and coordinate the robustness and anti-resonance ability.Consequently, the algorithm can suppress speed and torque fluctuation caused by the mechanical resonance and enhance the anti-disturbance ability of the system.The effectiveness of the proposed algorithm is verified by simulation. © 2016, The editorial office of Transaction of China Electrotechnical Society. All right reserved.