Zhao Yanan

Stress Analysis and Evaluation of High Pressure Hub

Through the analysis of three-dimensional hub model by using finite element, detailed stress distribution is obtained. On this basis, the dangerous sections of structural discontinuity regions are made stress analysis and classification by using stress linearization method, the stress evaluation is carried out through using design by analysis theory. The results show the structure is safe and reliable.

Position control of hydraulic servo system based on state observer and feedforward

In hydraulic servo system control, in order to ensure the high accuracy of the hydraulic servo system that is the system has strong anti-disturbance performance, infinite bandwidth, larger damping ratio and ideal static/dynamic stiffness are all required. As it is difficult to measure the load disturbance under normal circumstances, a state observer was adopted to evaluate the load disturbance. Then, the observed disturbance torque is fed forward, that can reduce the error caused by the load disturbances and increase the effective stiffness. Aiming at the controlled object with large inertia, the PD controller, which is needed to avoid unacceptable overshoot and improve system dynamic performance, was applied to position control. The system with or without load observer participating in control was compared by simulating; the simulation studies indicate that this method can enhance anti-disturbance ability and improve system dynamic performance.