Research On Control Method Of Electro-hydraulic Position Servo System Of Three-degree-of-freedom Heavy-load Swing Table

The multi-degree-of-freedom swing table is a typical physical simulation test equipment,and the control accuracy of its drive system determines the motion accuracy of the multi-degree-of-freedom swing table.The heavy-load swing table that can realize the three-degree-offreedom motion of roll,pitch,and heave,which is studied in this paper,uses an electrohydraulic position servo system as a driving device.The load structure has the characteristics of large size,large mass,large inertia,coupling interference of motion of various degrees of freedom.As a result,the structure of the swing table requires four sets of hydraulic cylinders to be driven synchronously to achieve heave motion,and there are problems such as poor position tracking performance during the motion.In order to improve the position tracking performance and synchronization accuracy of the three-degree-of-freedom heavy-load swing table movement,the research contents of its electro-hydraulic position servo system are as follows:Firstly,according to the structural characteristics of the three-degree-of-freedom heavyload swing table,the dynamic models of roll,pitch and heave motion are established,and the mathematical model of its electro-hydraulic position servo system is established.The coupling interference moment between roll and pitch motion,the interference force of roll and pitch motion on heave motion,and the influence of partial load of heave motion on the motion of heavy-load three-degree-of-freedom swing table are analyzed theoretically and simulated.Secondly,using ADAMS,AMESim and Matlab software,a three-degree-of-freedom heavy-load swing table virtual prototype was designed,and a virtual prototype simulation study based on a feedforward PID controller was carried out.The simulation shows that the feedforward PID controller cannot solve the influence of the coupling disturbance torque on the roll and pitch position servo system,and the tracking performance is poor.For the four-channel heave position servo system,an adjacent cross-coupling synchronization control strategy is designed,and the equivalent synchronization and adjacent cross-coupling synchronization control strategies are compared based on feedforward PID control.The simulation results show that the heave motion is greatly affected by disturbance force and partial load,and the simple use of feedforward PID controller and synchronous control strategy can not obtain satisfactory control effect.Finally,in order to solve the problem that the roll and pitch position servo system and the four-channel heave position servo system are greatly affected by interference factors,a nonlinear robust controller is designed through the backstepping method,which overcomes the influence of interference factors.The virtual prototype simulation shows that for the roll and pitch position servo system and the four-channel heave position servo system,the control effect of the robust control algorithm is significantly better than the feedforward PID control.The control effect of the robust control algorithm based on the adjacent cross-coupling synchronization control strategy is also significantly better than the robust control algorithm based on the equivalent synchronization control strategy,which verifies the effectiveness of the designed adjacent cross-coupling synchronization control strategy.In summary,the research content of this paper enriches the research theories and methods of the swing table,and has reference significance for the research of similar electro-hydraulic position servo systems and synchronous control systems,and also has certain engineering significance for the engineering realization and safe operation of the three-degree-of-freedom heavy-load swing table.