Design And Study Of Load Disturbance Observer For Two-mass Elastic System

AC servo system is widely used in industry and motion control field with its superior performance. Mechanical resonance phenomenon caused by the finite elasticity of the connecting device and the dynamic disturbance phenomenon by the load mutation exist in the power transmission mechanism, such as rolling mill, robot joint and so on. The existence of these two phenomena not only damages the equipment itself, but also affects the process and efficiency of production, reduces the quality of the work-piece, and deteriorates the quality of control, which restricts the development of industrial equipment ma nufacturing. Therefore, it is of great practical significance and influence to solve the problem of anti-resonance and anti-disturbance.This paper firstly studies single inertia load disturbance observer, and improve the structure of the DOB in single in ertia system. There are problems of dynamic speed drop caused by load or other external influences and periodic speed ripples in single inertia system. Those problems can be solved by improved disturbance observer, and the effect of DOB is verified by simu lation.Secondly, the two-inertia modeling of rolling mill and other transmission equipment is analyzed, and the related mechanism is analyzed. The contradiction between anti-resonance and anti-disturbance is studied, and its validation is verified by simulation. In order to solve this problem, a state feedback control strategy based on observer is proposed. There is no sensing device for the load side of the transmission mechanism, so that the state of the load is obtained by using the observer method. Its purpose is to suppress speed and torque fluctuation caused by the mechanical resonance, and to enhance the anti-disturbance ability of the system when the load is changed, which has good performance to suppress the dynamic changes. The scheme is combined with the fractional order disturbance observer and state observer. This paper makes a detailed study of the mechanism and the realization of the dual observers. Simulation results demonstrate that the effectiveness of the proposed method.Finally, the upwards algorithm is validated on the test platform of single inertia and two-inertia. Single inertia load disturbance observer can effectively solve the problem of the disturbance rejection and periodic speed ripples in low speed range. For load disturbance observer of two-inertia system, it can not only effectively estimate the state of load side of the transmission mechanism, but also solve the contradiction between the anti-resonance and anti-disturbance, while improving mechanical resonance suppression and disturbance rejection capability of system.