Theoretical and Experimental Analysis of the Hydraulic Actuator Used in the Active Reflector System

Abstract

In order to improve the control quality of the active reflector system which is used in the 500 m aperture spherical radio telescope (FAST) project, a study on hydraulic actuator is proposed. The dynamic performance of hydraulic actuator is due to the interaction of several physical phenomena. Modeling of such a system needs a unified approach to represent the nonlinear behavior characteristics. Bond graph model is ideal for this task. In addition, conventional PID control strategy cannot achieve the required accuracy and precision, so we combine grey prediction with PID control. Furthermore, a new adjustment mechanism is presented to change the grey step size, which is simple, automatic, less time-consuming, and efficient. Simulations and experiments on the actuator are carried out to evaluate the effectiveness of the proposed control method. In experiments, the velocity error is less than 0.05mm/s and the position error is less than 0.2mm. It shows the actuator meets the astronomical observation requirement totally.

Simulation of Hydraulic Cylinder Cushioning

“…The equation of the plane that this data forms is calculated as a mathematical representation of the results. These have the general form of the following equation: (17) where Lp is the piston stroke (in centimeters) and Qgroove is the flow rate through the groove in (in L/min). The coefficients a, b, and c, detailed in Table 1, are determined by least-squared best-fit for the different established experiments.…”

“…Bond graph modeling also shows a powerful applicability in analyzing the control strategies of dynamical mechanical and hydraulic systems [15][16][17]. Besides, it has also been successfully employed in detailed analyses of small-scale mechanical and hydraulic systems, such as pressure regulation valves [18,19].…”

A Nonlinear Vibration Compensation Method for Engineering Forging Hydraulic Press Using Tabu Search Algorithm

“…As a result, their proposed model has overcome the single-cylinder hydraulic press system's nonlinearities. Apart from the above, an adaptive control based on the back-step recursive approach is used in some works of literature [7]. During their work, they first assess the hydraulic press model based on physical features and then develop the speed controller based on this model using the back-step recursive method.…”