【作者】 蒋勇敏；

【导师】 许明恒；

【作者基本信息】 西南交通大学 ， 机械制造及其自动化， 2006， 博士

【摘要】 目前，在理论上还没有满意地解决轨迹几何函数与轨迹加工运动的关系问题，还不能找出全面符合工件曲线几何特性、机床运动特性、动力特性的理想加工运动。由于超高速加工，纳米加工，计算机集成制造的飞速发展，对机械制造技术提出了更高的要求，需要解决的问题是提高轨迹加工运动的综合控制性能：轨迹的几何精度、运动平稳性、控制适时性。轨迹控制是以一种运动来实现规定几何曲线的方法。轨迹的几何性质与轨迹运动的联系是轨迹控制的关键问题。假定加工轨迹运动全面符合几何要求，工艺要求，运动要求，建立数控机床加工运动的物理模型，包括位置控制模型，运动学模型，动力学模型，能量模型，相对空间模型。在理想的情况下，采用泛函多维空间理论、运动学、动力学、能量法等理论全面的研究曲线几何函数与运动空间的关系。研究结果表明：所有参数之间存在固有的对应关系，即加工轨迹运动的内在规律。根据参数之间的对应关系，可以控制变化简单的参数去实现变化复杂的参数，使控制简化。可以计算出各坐标轴的瞬态运动参数，对轨迹运动动态监控。一条轨迹的位置点有无穷多个，但运动规律只有一个，按运动规律控制的方法是最简捷、最全面的。用运动参数控制运动等于同时实现运动规律和几何规律，与位置控制相比，控制对象简化，计算少，精度高，运动平稳。经过试验和仿真，证明该方法是能够同时控制位置和运动的好方法。本文建立机床轨迹运动的物理模型，从理论方面深入研究轨迹运动的内在规律，找出能同时控制几何特性与运动特性的方法，并在反复的实验中发现新问题。在以下几个方面取得了一定的创新成果：1．理想运动状态物理模型的建立分析数控机床轨迹运动的特点，提炼主要因素，建立物理模型。假设理想的轨迹运动存在，以数控加工的要求作为约束条件，推导理想条件下加工轨迹运动的运动规律。分别以运动学、动力学、能量法等理论建立运动模型，分析轨迹几何函数、工艺参数，运动规划参数等在各模型中的作用，建立几何因素与轨迹运动的对应规律。2．轨迹控制新方法—运动规律控制轨迹的几何性质是由运动实现的，而且运动规律与几何参数是准确对应的。传统的位置控制不能解决无穷多点的繁琐计算的问题。但是，对于一种运动来说运动规律只有一个，体现在某些参数是常数或简单表达式。控制这些参数和变化规律同样可以实现轨迹。这种方法计算量小，精度高，面向运动控制，控制更全面。3．基于参考时间的轨迹运动规划与控制方法几何参数对参考时间的变化率是人为建立的相对关系，因此可以用参考时间为尺度度量几何参数变化的快慢。一般选择加工关键因素为参考时间，相对变化率为常数。其物理意义是几何参数相对于参考时间成比例变化。如线切割加工速度与电极间的电压成正比，提出根据参考时间规划，以实际的参考时间的变化率修正规划，这样计算简便，能准确的按几何特性规划，能适应适时性要求和环境应变的要求。4．编制了运动规律控制方法的单片机数控软件和计算机仿真软件经过试验和仿真，证明运动规律控制轨迹的方法是能同时控制位置和运动的好方法，也是加工轨迹控制技术的发展趋势。更多还原

【Abstract】 At present, the problem of the relation between geometric function and machining locus motion has not been resolved satisfactorily in theoretical studies. The idea cutting motion which satisfy requirements of locus geometric, machine tool motion and driving force can not be found. With developing of super speed machining, nanometer machining and CIMS, the more and more demand for manufacturing technique is presented. The problem need to be resolved is to pick up the synthetic control ability of machining locus motion. Such as trajectory geometric precision, smooth motion, control timely, etc. Trajectory control is the way to realize prescriptive geometric curve with motion. The key problem is the relationship between geometric characteristic and locus motion characteristic.Assume that the machining locus motion completely suit the requirement which including geometric, dynamic and manufacturing process requirement, the physics model is built, such as position control model, motion model, dynamics model, energy model, relative space model etc. The relationship between geometric function and machining locus motion is studied by means of theories, such as the norm functional multidimensional space theory, kinematics, dynamics, energy method. It is shown by studying result, that there are inherent correspond relation among the parameters, in other words, there is internality regularity of machining locus motion. According this law, to control the simple parameter can realize the complex one. It makes the control process simply. The transient motion parameter of every coordinate axes can be calculated to monitor the locus motion. The numbers of position point are infinity, the regularity, however, is only one. The control method with motion regularity is a short-cut and all-sided method. To control locus motion by control motion regularity is most short-cut and all-sided method. It equals to control motion regularity and geometric law. This thesis describes a new way to control trajectory with motion regularity instead position and give up interpolation. It is proved by experiment and simulation that it is a good way to control geometry and motion comprehensively, to reduce computation times and to increase the capacity of environmental adaptation for path planning.The physics model of machine tool locus motion is built to study internality regularity of machining locus motion theoretically. A good way to control geometry and motion comprehensively is presented, when it is used in practice again and again, new problem is found and studied. Some creative work has been down:a.) to build the physics model of idea motion stateThe speciality of locus motion of CNC machine tool is studied to refine main factors and build-up the physics model. Assume that there is idea machining locus motion and taking the requirement of CNC machining as constraint condition, the motive regularity of locus motion in the idea condition is derived. Motion model is built separately with the follow theory: kinematics, dynamics, energy method. It is studied how the geometric parameter, manufacturing process and motion planning parameter works in this model. The correspond law between geometry factor and motion factor is set up.b.) A new strategy to control locus based on motive regularityThe trajectory geometric character is worked out by motion and the motive regularity correspond to geometric character accurately. The problem of trivially calculation for infinity points can not be solved by traditional position control way. But as far as a motion, there only one motive law, it is shown that some motive parameter is constant or simple equation. To control it can work out locus equally. This way is very good in many characters, such as less calculation, high precision, simple motion control, comprehensive control, etc.c.) Locus motion planning and control method with reference timeThe relation between geometric parameter and reference time is relative relation set up artificially. The tempo of geometric parameter change is measured by reference time as metric, the relatively rate of change is decided by manufacturing process, it is usually a content. Its physics signification is that geometric parameter varies with reference time proportionately. For example, the machining motion velocity of electro-corrosion line cutting is proportional to the voltage between the electrodes, It is a simple way to plan with reference time and to readjust the plan by actual rate of reference time change. It is good way for simple calculation, accurate planning according geometric quality, satisfaction of updated requirements and environment change requirements.d.) Programming software for microcontroller and computer simulationbased on motion lawIt is proved by experiment and simulation that it is a good way to control geometry and motion comprehensively, to reduce computation times and to increase the ability of environmental adaptation for path planning. It is the evolution direction of locus control technology.更多还原