Anilysis And Control Design For Rate Servo System With High Precision

In this paper, the performance of a high precision rate servo system with a highspeed and large moment of inertia performance is studied. The research work includes:the establishment of servo system controlled object mathematical model and theanalysis on impact factors of system speed tracking performance, which mainlyinclude disturbance torque and the system uncertainty. Then a robust controller basedon disturbance observer is designed and the simulation result is given to show theeffects of the proposed method.First, the impact factors of speed tracking precision on the performance of thesystem is analyzed, and the mathematical model of the servo system is derived. Thekey performance indicators for location-based closed-loop servo system lies in thespeed stability. Its impact factors are mainly divided into external disturbance torquesand systematic uncertainties.Second, the effect of disturbance torque on servo system speed tracking precisionis analyzed. Also, transfer-function-based evaluation and norm-based evaluation forthe speed stability are given respectively.Next, the mathematical models of the system uncertainties are established. Basedparameter sensitivity, comparison of various parameters perturbations effect onvelocity tracking performance is stated. By simulation results, the major influenceuncertainty factors are pointed out．Further, mathematical model of the system withuncertainties is established.Finally, the disturbance-observer-based robust controller design is given.Consider that the robust control design based on single-degree-of-freedom has a majorflaw: the weighting function of disturbance torques either applies only to interferencesuppression with certain frequency or introduce a great conservative. To solve thisproblem, a robust controller based on disturbance observer is designed. Thedisturbance-observer-based inner loop is used to suppress the disturbance while theouter robust-controller-based loop is use to guarantee the tracking performance of thesystem. The simulation result is given to show the effects of the proposed method.