【作者】 武建新；

【导师】 李强；

【作者基本信息】 内蒙古工业大学 ， 固体力学， 2007， 博士

【摘要】 固体火箭发动机是航天工程中重要的动力装备,因此,研制固体火箭发动机安全可靠的生产装备是机械工程领域重要的课题。本文以固体火箭发动机复杂型腔药柱整形加工机床为研究对象,完成了固体火箭发动机药柱五自由度混联整形机床的方案设计,确定了基于PC主机——多专用CPU的开放式数控系统的结构,并规划了数控系统的主要模块。采用远程控制方法,实现操作工人“零暴露”生产。在考虑固体推进剂对冲击、摩擦、受热和静电敏感的基础上,用“模拟药”(即物理性能与固体推进剂相似的钝药)进行切削加工试验。试验结果表明,固体推进剂药柱机械加工所需切削力很小;刀具的温度随切削用量的增大而增大;最大切削用量时刀具的温度和静电累积都小于固体推进剂的安全温度和安全静电累计量。试验结果证实了固体推进剂药柱加工的可行性。为了减少加工中刀具对药柱的振动和冲击,保证药柱整形加工过程的安全性,论文对整型机床的主要部件并联机构和可偏转主轴系统进行速度和加速度分析。分析结果表明,在给定轨迹下,并联机构动平台中心的速度和加速度变化平稳,产生的振动很小,可以完成药柱整形加工。在主轴系统中,主轴电机和偏转电机转速的升高都会使刀具的旋转速度和旋转角加速度波动增大,实际加工时可能产生振动;刀具的偏转速度和角加速度只与偏转电机的转速有关,并随偏转电机的转速升高而增大,但幅值很小。综合两个部件的速度和加速度分析结果得到:并联机构输出的速度和加速度可以通过数控系统控制在要求的范围内;而由主轴系统引起的刀具速度和加速度波动是主轴系统固有的特性只能通过对该系统设计参数进行优化设计,使动力学性能达到规定要求。机电耦联系统动力学分析的核心是伺服电机动力学建模,文中利用伺服电机参数,在建立电路和机械能量方程的基础上,应用拉格朗日-麦克斯韦方程,通过Park变换,将三相定子参考系的拉格朗日-麦克斯韦方程变换到两相转子参考系。首次推导了便于实施控制的永磁同步伺服电机两相转子参考系的机电耦联动力学方程。在对比伺服电机各种电流控制方案优缺点的基础上,选定了本系统伺服电机的电流控制方案。以刀具偏转伺服电机为算例,进行了机电耦联动力学仿真。仿真结果展示了伺服电机机电耦联动力学方程推导正确,电机电流控制方案合理有效。完成了主轴系统机电耦联动力学分析。利用Park变换推导了二自由度、永磁同步伺服电机驱动的主轴系统机电耦合动力学微分方程。比较非线性、变系数常微分方程组的数值解法,选用高效Hamming方法实现了微分方程的快速求解。以刀具加速度最小为目标函数;以机构的机械设计参数和电机的电气参数为设计变量;以机电耦联动力学微分方程和设计变量的取值范围为约束条件,建立了机电耦联动力学优化模型。经过多方面的探索,构造了可以实现该工程问题可行的优化方法——指数型自适应惯性权重粒子群算法。并通过多个测试函数对该算法进行了检验。完成了该算法的收敛性分析。利用该算法完成了以各构件的机械参数和驱动电机电气参数为设计变量的主轴系统动力学优化。实现了减小刀具加速度幅值和改善刀具偏转电机波纹转矩的研究目标,解决了机电耦联系统动力学优化的工程问题。更多还原

【Abstract】 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.更多还原