The Stracture Optimization Of Rocket Propellant Filling System And Research On Impedance Control

The filling of rocket propellant is an important part of rocket launch. The propellant has a strongly corrosive and toxic,whose filling work demands high-risk.Unmanned and automatic propellant filling should be realized,which can not only improve the efficiency,but also greatly reduce the operating risk.The filling of rocket propellant is an important part of rocke t launch. The propellant has a strong corrosive and toxic,whose filling work demands high-risk.Unmanned and automatic propellant filling should be realized,which can not only improve the efficiency,but also greatly reduce the operating risk.Because of the external factors such as wind,the rocket ready to launch usually generate irregular freedom of movement.It will generate excessive contact force or torque in the rocket valve,which may damage the rocket body.So when the rocket propellant filling device is designed,it should have the ability of all degrees of freedom movement,and in addition to the ability of compliance.In order to minimize the system power and reduce the operating cost,the optimization of the Stewart platform should be researched;in order to expand the position loop bandwidth as much as possible,the characteristics of position servo system should be researched;in order to guarantee the stability of system and make the contact force conform the expectations,the characteristics of force control system should be researched.They are the main contents of this paper.In order to consist with the design requirements of the Stewart platform,it takes the system power to a minimum as the objective function.And the genetic algorithm(GA) is used to optimize the design.Then the optimized design is verified by simulation.After hydraulic kinetic mechanism is designed,the mold of position servo system is established.In order to improve the single channel damping ratio and the position loop bandwidth,the meth od of dynamic pressure feedback is used.On the basis of the position loop,the impedance control strategy is adopted to establish.The stability and its influencing factors are analyzed.Without knowing the environmental parameters,the classical impedance controller is not good in tracking the expect force.According to the Lyapunov stability theory,an on-line environment parameters estimation based on the feedback force error is presented.A Lyapunov energy function is found to deduce the adjustment rules of controller parameters,and the stability is demonstrated.Finally,two kinds of control strategy is used to multi-DOF compliant control,and the on-line environment parameters estimation strategy is proved to have a good control performance.