基于应力刚化效应的动态特性可调微动平台设计新方法

发布时间：2018-01-04 11:03

本文关键词：基于应力刚化效应的动态特性可调微动平台设计新方法　出处：《机械工程学报》2015年23期 　论文类型：期刊论文

【摘要】：针对现有基于柔性铰链的微动平台动态特性受材料特性、设计制造等误差影响,难以满足精密微动平台对动态响应(特别是可变频率操作)的高要求,基于应力刚化效应,提出了动态特性可调的微动平台设计新方法,推导预应力作用下一端固定一端导向梁的等效刚度和质量公式;基于对称布置假设,建立含有弹片式柔性铰链(下面简称弹片)组数(离散变量)和截面尺寸(连续变量)的离散连续变量复合优化模型,释放承载刚度约束,获得截面尺寸含有弹片组数变量的精确解系列,分析了给定预应力下不同弹片组数微动平台的承载刚度和频率调节范围,从而通过承载刚度约束和频率调节范围要求确定弹片组数。通过数值算例,验证了推导计算模型求解精度和所提设计方法的应用有效性。计算结果表明,与有限元分析结果相比,本模型的计算结果相对误差小于2%,实现了给定工作刚度、频率和承载刚度约束的微动平台最优结构设计。所提方法实现了刚度和频率大范围的调整,不但降低了加工精度要求,还为动态特性自适应匹配的智能微动平台提供一种实现途径。
[Abstract]:The dynamic characteristics of the existing flexible hinge based fretting platform are affected by the material characteristics, design and manufacture errors, so it is difficult to meet the high requirement of dynamic response (especially the variable frequency operation) of the precision fretting platform. Based on the stress stiffening effect, a new design method of fretting platform with adjustable dynamic characteristics is proposed, and the equivalent stiffness and mass formulas of one end fixed and one end guide beam under prestress are derived. Based on the hypothesis of symmetrical arrangement, a composite optimization model of discrete continuous variables with elastic flexure hinges (hereinafter referred to as shrapnel) groups (discrete variables) and cross-section dimensions (continuous variables) is established to release the bearing stiffness constraints. A series of exact solutions of the section size including the number variables of the shrapnel are obtained, and the bearing stiffness and frequency adjustment range of the fretting platform with different number of shrapnel groups under given prestress are analyzed. Thus, the number of shrapnel is determined by the constraint of bearing stiffness and the range of frequency adjustment. The accuracy of the model and the validity of the proposed design method are verified by numerical examples. The calculation results show that the proposed method is effective. Compared with the results of finite element analysis, the relative error of the model is less than 2, and the given working stiffness is realized. Optimal structural design of fretting platform with frequency and bearing stiffness constraints. The proposed method realizes the adjustment of stiffness and frequency in a wide range, which not only reduces the requirement of machining accuracy. It also provides a way to realize the intelligent fretting platform with adaptive matching of dynamic characteristics.
【作者单位】：广东工业大学微电子精密制造技术与装备教育部重点实验室;佛山市南海区广工大数控装备协同创新研究院;
【基金】：国家自然科学基金(U1134004,50905033) 国家重点基础研究发展计划(973计划,2011CB013104) 广东省自然科学基金(2015A030312008) 广州市科技计划(201510010281) 广东省科技计划(2013B010402014,2012CXZD0020)资助项目
【分类号】：TH703.8
【正文快照】： 0前言10前言柔顺机构通过构件弹性变形来实现力、运动、能量等的传递与转换,因具有体积小、无机械摩擦、无间隙、免润滑等优点而受到广泛的研究[1],并发展起一门新兴的学科——柔顺机构学。柔性铰链被大量应用于柔顺机构的设计,在快刀伺服[2-3]、宏微复合平台[4]等精密工程领

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