Research On Pressure Coupled Sysnchro-driven Electrohydraulic Servo Motors

Three-Axis flight simulators are key experiments to simulate flight attitude ofaircrafts such as missiles, spacecraft and so on. The simulation of aircrafts on flightsimulators can provide references to improve and redesign aircrafts. With thedevelopment of the performance of inertial navigation components, the dynamicperformance indicators of the flight simulators has been enhancing, and only horizontaldrive solutions can satisfy the demands.Since the middle and outer frame of thehorizontal hydraulic flight simulator both use a hydraulic motor to drive loads, theresearch on the model of the double synchronously driven by hydraulic motor systemand the design of synchronous controller is of great importance.Two hydraulic motors which have the same displacement have the same torqueoutput by means of connecting the corresponding chambers of the two hydraulic motorsseparately using pressure coupled channels.This paper puts forward the mathematicalmodel of the double synchronous motor drive system considering the stiffness of theframes. On the basis of the modeling, the paper simulates and analyzes how pressurecoupled channels and stiffness of the frames affect the frequency characteristicsandconsistency on two modes, which are: two hydraulic motors drive two loadsseparately (Peer to peer Mode) and drive one common load (Common drive Mode).Cross coupling type synchronization control strategy is adopt to synchronous drivesystem, which makes the synchronization accuracy of the displacement, speed andacceleration of the double-motor system are very high. Considering the double-motorsystem as a control object, the paper designs indicators of the controller which suits thebandwidth of the system.Experiments show that pressure coupled channels can enhance the consistency ofthe double-motor subsystem.The pressure coupled channels can only reduce the middleand high frequency synchronization error due to the differentfriction torques of the twomotors; the rigid connection reduces the natural frequency of the system, but itimproves the consistency of the double-motor subsystem. The cross-couplingsynchronizing controllers can be satisfied.