Design And Research Of Displacement-speed Composite Regulating Electro-hydrostatic Actuator For Rocket Rudder

Electro-hydrostatic servo technique is a hybrid of hydraulic volume control and ser-vo motor, it’s a newly developed mechatronics technique in last20years. It combinesthe advantages of hydraulics’ high power density and self-lubrication with the convenientwiring and control agility of motor drive system, so it has been paid special attention fromboth academia and industry around the world, and has been an important research branchof energy-saving hydraulics.Coincided with the power-by-wire trend in aerospace, electro-hydrostatic actua-tor (EHA) applying in aircraft rudder surface control has become a research hotspot. Sometypes of US’s latest combat aircraft have equipped EHA, however, present EHA almostall using constant displacement pump though it has been figured out that with pump dis-placement adjustable, the new variable pump variable motor (VPVM) actuator may havebetter dynamic performance and be more energy-efcient. So, In this subject I researchedthe design and application of VPVM actuation system in rocket rudder and its capability.At first, I accomplished the parts selection and actuator integrated structural designbased upon rocket rudder’s kinematics and dynamics analysis; and then, set up the math-ematical model of entire system from parts to subsystems. Thus, I lay the base for controlalgorithm design and module analyze.With two control elements-variable pump and servo motor, whose outputs-displacementand speed-are multiplied, the system becomes essentially nonlinear, if utilizing feedbacklinearization, and then conduct pole assignment or optimum control, the system’s robust-ness will be poor. By analyzing rocket rudder’s working states, the decoupling control isrealized by transmitting diferent feedbacks to pump and motor, with a fuzzy controller toset the control rules. The simulation and experiment result shows that displacement-speedcomposite regulation has better dynamic performance than single variable regulation andthe energy efciency is also improved. With a compact EHA design, all module index-es are also fulfilled. These both prove the superiority of VPVM EHA, and indicate theefectiveness and rationality of the research methodology in this paper.