Dynamics Analysis And Optimization On Electromechanical Coupling System Of Solid Rocket Motor Reshaping Machine Tool

Solid-propellant rocket motor is important power equipment in space engineering; therefore, the development of safe and reliable reshaping equipments for solid-propellant rocket motor is an indispensable task in mechanical engineering.Aiming at reshaping equipments for solid-propellant rocket motor, with the design prototype of 5DOF hybrid type parallel machine tool, the structure and planned principal modules of open numerical control system of PC hosted multi special CPU is presented in the paper. Remote control method is adopted and"Zero exposure of operator"manufacturing is realized. Machining experiment with"simulated propellent"(i.e. bluntness propellent with similar physical property of solid propellant) has been performed on the consideration of sensitivity of impact, friction, warming and static electricity. Experimental results indicated that cutting force of solid-propellant is very small, while tool temperature rises up with the increase of cutting parameters. The highest temperature and maximal static electricity accumulation of cutting are both less than the safe limitation of solid-propellant. Machining feasibility of solid-propellant has been verified by machining experiment.Velocity and acceleration of parallel mechanism and swing spindle system, as main parts of reshaping machine tool are analyzed in order to reduce vibration and impact of tool, and to ensure machining safety. Analytical results indicate that moving velocity and acceleration of motion platform are smooth, vibration of parallel mechanism is small and propellent machining can be accomplished. In the spindle system, the rise of speed in spindle motor will cause vibration amplification of the tool, so vibration will be appeared in the actual machining. Swing speed and acceleration of tool are only related to swing motor speed and amplified with the increase of swing motor speed, but the value of amplitude is not too large. Based on the results integration of two partial analysis of speed and acceleration, we can conclude that speed and acceleration exported form parallel mechanism can be controlled in demand range by numerical control system, and vibration of spindle system is inherent property. So optimization design on design variables of dynamics of spindle system is necessary in order to meet the needs of dynamics performance.Servomotor dynamics modeling is the key issue of electromechanical coupling dynamics analysis. Lagrange-Maxwell equations and Park transform are adopted based on electrical and mechanical energy equations consisting of servomotor parameters. Lagrange-Maxwell equations are transformed from three-phase stator reference coordinates to two-phase rotor reference coordinates. Electromechanical coupling dynamics equations of permanent magnet synchronous servomotor in two-phase reference coordinates are obtained for the first time. Current control scheme is chosen for the system after contrasting with different kinds of current control plan. Electromechanical coupling dynamics system is simulated with the swing servomotor as an example. Simulation results show that the electromechanical coupling dynamics equations deduced for servomotor are correct, and current control schemes are reasonable.Driven by permanent magnet synchronous servomotor, 2DOF spindle system dynamics differential equations have been deduced. After the comparison of numerical solution methods of dynamics differential equations for nonlinearity and variable coefficient ordinary differential equations, Hamming method is adopted as the rapid solution.The electromechanical coupling dynamics optimization model of spindle system is established, which the vibration acceleration of tool is taken as objective function, mechanical and electrical design parameters of mechanism are taken as design variables. Particle swarm algorithm with exponential type adaptive inertia weighted method is fabricated after omnifarious seeking, which can solve the electromechanical coupling dynamics optimization problem uniquely. The new algorithm has been verified by many kinds of test functions and convergence analysis has been realized. At last, the design variables of spindle system which consist of mechanical parameters of each member and electrical parameters of drive motor have been optimized by the new optimization method. Thus, research targets, to decrease vibration amplitude of tool acceleration and improve ripple torque of swing motor have been realized, and the electromechanical coupling dynamics optimization problem has been solved successfully by all the above endeavor.