【作者】 张雷；

【导师】 邬义杰；

【作者基本信息】 浙江大学 ， 机械制造及其自动化， 2012， 博士

【摘要】 活塞异形销孔能够显著改善销孔座应力分布,提高活塞的使用寿命,但由于活塞异形销孔结构的特殊性,给其精密加工提出了难题。对此,本文采用超磁致伸缩材料(Giant Magnetostrictive Material,GMM)嵌入刀杆内部,研制嵌入式GMM微进给机构以实现活塞异形销孔的精密加工。在研制过程中深入系统地研究了活塞异形销孔加工工艺特点、微进给机构的设计方法以及精密位移数控等技术,如：嵌入式GMM微进给机构的机-电-磁多场多目标耦合优化设计方法；交、直流分离式驱动结构；动态迟滞非线性建模；实时可编程数控系统；前馈补偿复合PID控制策略；预压力、偏置磁场等对嵌入式GMM微进给机构输出位移的影响等。在此基础上,建立了活塞异形销孔精密加工的嵌入式GMM微进给机构测控平台,并开展了嵌入式GMM微进给机构的机、电、磁、热主要性能测试和活塞异形销孔精密加工的试验工作。第1章介绍课题的研究背景和意义,然后对活塞异形销孔精密加工技术、嵌入式GMM微进给机构的设计方法、迟滞非线性建模方法、微位移跟踪控制策略的研究现状进行综述,指出目前嵌入式GMM应用研究中所存在的一些问题,并阐述了本文的研究内容和选题意义。第2章针对非圆截面异形销孔的精密加工,采用超磁致伸缩材料嵌入镗杆本体,通过磁场驱动使其产生弯曲变形,实现径向微进给运动的结构方案。首先,为满足嵌入式GMM微进给机构精密加工异形销孔的频响、行程、刚度等机械性能需求,对其变形刚度、抗扭转刚度、一阶固有频率进行数学建模；其次,对励磁机构的设计方案进行优选、建模,同时考虑励磁线圈的阻抗、电流、电压、功率等匹配问题,并降低系统整体能耗及发热。为合理配置该机构电-磁-机多场耦合的性能参数,采用多目标遗传算法对该机构多场优化设计模型进行求解。最后,按预期的技术指标要求对优化设计后的嵌入式GMM微进给机构主要性能进行测试验证。第3章采用理论和实验建模两种方法,分别建立了嵌入式GMM微位移机构加工活塞异形销孔的迟滞非线性数学模型和迟滞线性化的数学模型。首先,通过对控制系统的模块化机理建模和动力学分析,建立了嵌入式GMM微进给机构的迟滞非线性数学模型。其次,针对该模型中未知参数较多,且部分参数难以准确获得,存在可操作性和实用性差的问题,进一步采用实验建模的方法。根据活塞非圆截面(椭圆)异形销孔加工刀刀具轨迹的特点,对实验测得的驱动电流与输出位移进行相关分析,建立了嵌入式GMM微进给机构迟滞线性化的数学模型。在此基础上,以活塞倒锥形和倒椭圆形销孔加工轨迹跟踪控制为例,开展了基于该线性化模型的逆模型开环补偿控制实验,验证了该线性化建模方法和基于其逆模型的开环补偿控制能有效克服嵌入式GMM微进给机构迟滞非线性。第4章在第3章迟滞非线性建模和开环逆模型补偿控制研究的基础上,针对嵌入式GMM微进给机构交、直流线圈分离驱动的方式,采用前馈补偿复合PID的控制策略实现刀具轨迹的闭环跟踪控制,进一步提高位移跟踪控制的精度。在PID参数辨识试验后,经不同控制方法的对比实验,验证了前馈补偿复合PID控制策略能有效提高嵌入式GMM微进给机构的位移跟踪精度。并以倒椭圆形销孔加工轨迹为例进行了前馈补偿复合PID的闭环控制实验,结果表明,该控制策略相比开环补偿控制能有效提高位移跟踪精度。第5章在嵌入式GMM微进给机构的结构设计和控制策略研究的基础上,进一步开展活塞异形销孔精密加工控制系统的软、硬件设计工作。该控制系统主要分为上位机PC和下位机DSP两部分。其中,上位机主要实现人机交互、数据的采集、处理和保存等功能；而下位DSP作为可编程控制系统,主要实现嵌入式GMM微进给机构的运动与机床主轴转动、拖板进给运动的联动控制。根据嵌入式GMM微进给机构的交、直流分离式驱动线圈结构,采用DSP控制板分别控制两个线性恒流功放,驱动准直流线圈和交流线圈工作。同时,说明了一种双电涡流测量的方法暂时无法实现任意角度下微位移信号反馈的原因,但能实现圆截面异形销孔加工的闭环反馈,并通过实验验证了该方法的可行性和检测的准确性。第6章介绍了嵌入式GMM微进给机构的性能综合测试平台,并开展嵌入式GMM微进给机构性能的静态测试和异形销孔的加工试验工作。静态测试实验包括：预压力对机构输出位移的影响实验；偏置磁场对机构位移输出的影响测试;频响特性测试；重复定位精度测试。动态加工试验分析包括：活塞倒锥形和倒椭圆形销孔的加工试验与分析。试验结果表明,嵌入式GMM微进给机构精密加工活塞异形销孔的质量(尺寸精度、表面粗糙度)均达到了预期技术指标的要求。第7章 概括全文的主要研究工作,并对将来的研究工作作了展望。更多还原

【Abstract】 that the optimized design fully meet the requirements of non-cylindrical holes precision machining.In chapter 3, The linearized dynamic hysteresis model of EGMM is established respectively by theoretical and experimental based on the feature of non-cylindrical holes precision machining, it constituted pure time delay part and linearity aspects to solve the problem of hysteresis and nonlinearity. The open-loop control experiments showed that the inversed model can effectively overcome the hysteresis nonlinearity of EGMM.In chapter 3, the composite control strategy of closed-loop control is proposed to improve the accuracy of EGMM tracking displacements. It applied PID control hybrid with feed-forward compensation and repetitive control for AC and DC powers independently driven coils based on the hysteresis modeling of EGMM and open-loop control experiments. While, the currents control in the bias DC coil applied PI control hybrid with feed-forward compensation to realize the cutting path control on Z-direction. And the currents control in the AC coil applied PD control hybrid with PD control to realize the cutting path control on circumferential-direction. After PID parameters identification and the results of different control methods showed, the composite control strategy improved the tracking displacement accuracy of EGMM significantlyIn chapter 5, the control system hardware and software design based on working principles and EGMM structural. It’s constituted by the host computer PC and programmable real-time control system. And applied Digital Signital Processor (DSP, TMS320F2812) as real-time control system to control two linearity constant current amplifiers, which driven two excitation coils as AC and DC independently. Then, In order to improve the system accuracy and reliability, two eddy-current sensors orthogonal applied, then get the micro-displacement of EGMM as feedback signals in closed-loop control, and it’s proved by experiments.In chapter 6, the experimental platform for EGMM precision machining non-cylindrical holes is built up. Then, the static tested for EGMM including: the relation tests between output displacement, the pre-stress and the biased magnetic field. And the test for systematic frequency response characteristics. The dynamic experiments including: the inverted cone pin-hole in piston precision machining. the inverted cone pin-hole with oval cross-section in piston precision machining. The precision machining results showed, the quality of non-cylindrical holes are fully meet the desired technical indicators, including dimensional accuracy and surface roughness.In chapter 7, the main conclusions of this dissertation are summarized and the future research work is put forward.The non-cylindrical holes of a piston can remarkable increase its using time. Due to the particularity of non-cylindrical holes of a piston, and the problem appeared in non-cylindrical holes precision machining. In order to solve this problem, a new mechanism is proposed using Giant Magnetostrictive Material (GMM) embedded into the component, to realize the non-cylindrical holes precision machining. Some key technologies of Embedded Giant Magnetostrictive Mechanism (EGMM) are studied comprehensively and systematically, such as:The optimize method of EGMM in multi-field and coupled parameters (mechanical, electrical, magnetic and thermal). The structural of excitation coils drive by AC and DC powers independently. The dynamic hysteresis nonlinearity models of EGMM. The design of programmable and real-time control system. The control strategy of non-cylindrical holes precision machining by feed-forward compensation and repetitive control hybrid with PID control. The inference of the pre-stress and the biased magnetic field to the displacement of EGMM. The testing platform of EGMM to precision machining non-cylindrical holes is constructed.In chapter 1, the research background and significance of non-cylindrical holes precision machining by EGMM are stated. Such as:The present technologies of piston with non-cylindrical holes precision machining, the design methods of EGMM, the hysteresis nonlinearity models, the control strategy of micro-displacement tracking, et al. and then the main content of this dissertation and the project significance are proposed with the problems and shortages in the above researches.In chapter 2, based on the needs of non-cylindrical holes precision machining, the structural comparison of excitation coils and the structure of excitation coil driven by AC and DC powers independently is designed, and the multi-objective optimization model of EGMM integrated with electric, magnetic and mechanical parameters are proposed. Then, the multi-objective genetic glgorithm is applied to solve the multi-objective optimization equations of EGMM. The experimental results showed更多还原