压电式微夹持器设计、建模与实验

发布时间：2017-12-31 12:09

本文关键词：压电式微夹持器设计、建模与实验　出处：《江西理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：微夹持器广泛应用于生物工程、医疗科学、微机电系统和航空航天等前沿领域,为了实现夹持不规则形状的微小物体、避免对其造成损伤和实现稳定释放,对微夹持器进行设计、建模和释放操作具有重要的理论和实际意义。本文采用实验设计的方法设计了两种微夹持器,并对其进行了性能优化和释放操作,主要内容如下:采用杠杆原理设计了一种新型的平面微夹持器,为了综合平衡微夹持器的张合量、夹持力灵敏度与快速响应,提出一种基于Kriging模型的性能优化方法。采用有限元软件ANSYS建立夹持器的参数化有限元模型,基于该模型得到对应不同结构参数的各性能指标值,即放大倍数、固有频率、输出刚度和最大应力。采用拉丁超立方抽样方法确定试验点,采用ANSYS计算各试验点对应的响应值。根据试验点进行相关性分析以确定对夹持器性能影响较大的结构参数,并将其作为优化设计变量。根据试验样本点采用Kriging理论建立能反映微夹持器性能指标与设计变量之间关系的非线性模型,为微夹持器的多目标优化提供精确的理论模型。建立以夹持器的放大倍数、固有频率和输出刚度为目标,强度为约束的多目标优化模型,采用多目标遗传算法对其进行全局寻优得到3目标Pareto最优解集,对3个性能指标进行权衡以从Pareto解集中选取最优设计方案。比较分析优化前与优化后的微夹持器各性能指标可知,放大倍数增大了7.4%,固有频率增大了16.46%,输出刚度增大了9.84%,最大应力减小了5.75%,说明所提出的性能优化方法的有效性。为了避免平面微夹持器在夹持微小对象过程中对其造成损伤或脱落,要求对夹持力进行预测和控制。提出了一种将电阻式应变片集成于微夹持器结构实现结构-传感一体化设计。以夹持力产生的应变最大、压电陶瓷驱动力产生的应变最小为目标对传感单元的尺寸参数进行优化设计。采用最小二乘方法分别标定压电驱动器输入电压、夹持力与力传感单元应变之间的关系。结果表明,描述驱动电压与传感单元应变的关系为3阶多项式,力传感单元应变与夹持力之间的关系为线性关系。可得出夹持力与驱动电压之间的关系为3阶多项式,利用该关系式可实现预测和控制夹持力。所提出的设计思路和标定方法为微夹持器设计提供一种新思路。针对平面微夹持器在夹持微小物体过程中的粘着问题,提出了一种基于压电振动控制的释放操作方法。基于弹性粘着理论证明了利用压电振动产生的惯性力可克服微夹持器与微小物体之间的粘着力,说明了该释放操作方法的可行性。采用实验方法建立反映压电微夹持器振动特性的动态模型,基于该模型得出稳定释放微小物体时驱动器输入电压幅值和频率应满足的条件。以一种微夹持器为对象搭建实验平台进行微小物体的释放实验,实验结果表明所提出的释放操作方法的可行性。同时,实验结果表明微小物体的尺寸越小释放越困难,需要越大的惯性力克服其受到的粘着力。针对平面微夹持器夹持微小物体时为2点接触,不能适应不规则形状微小物体的夹持操作,设计了一种能夹持不同大小和形状不规则物体的新型空间微夹持器,由两个相互垂直放置的夹持支链形成空间4点接触式夹持。夹持支链采用二级杠杆原理设计,支链设计下凹槽和上凹槽结构,将上凹槽与下凹槽相互嵌套实现采用一个驱动器同时驱动两个支链。为了提高该微夹持器的夹持平稳性和张合量,提出了一种基于支持向量机建立其性能指标与结构参数之间关系的回归模型,基于该模型对性能指标进行优化。采用所设计的空间微夹持器分别对小螺钉和小电阻进行夹持操作实验,实验结果表明微夹持器能稳定地夹持它们,说明了微夹持器设计和优化的有效性。
[Abstract]:The micro gripper is widely used in biological engineering, medical science, Frontiers of MEMS and aerospace etc., in order to realize the micro object clamping of irregular shape, avoid damage and achieve stability on its release, the micro gripper is designed, it has important theoretical and practical significance of modeling and release operations. This paper designed two kinds of micro gripper using experimental design method, and the performance optimization and release operation, the main contents are as follows: using the lever principle to design a new type of planar micro gripper, in order to balance the micro gripper with a clamping force, sensitivity and rapid response and put forward a performance optimization method based on Kriging model. The parameterized finite element model established by finite element software ANSYS holder, the performance index of the model corresponding to different structure parameters based on the value of the magnification, The natural frequency, output stiffness and maximum stress. By using Latin hypercube sampling method to determine the test point, response is calculated by ANSYS corresponding to the experimental values. The correlation analysis was performed according to the test point to determine the gripper performance effects of structure parameters of the larger, and as optimization design variables. According to the test samples. Using Kriging theory to establish the nonlinear model can reflect the Microgripping relationship between the performance index and the design variables, provide an accurate theoretical model of multi-objective optimization for micro gripper is established. The magnification to grip, natural frequency and output stiffness as the goal, the strength for the multi-objective optimization model with constraints. The multi-objective genetic algorithm for global optimization of the 3 target Pareto optimal solution set, on the 3 performance indicators to weigh on choosing the optimal design scheme from Pareto. A comparative analysis of the advantages and optimization After the micro gripper and each performance index of the magnification increases by 7.4%, the natural frequency is increased by 16.46%, the output stiffness increases by 9.84%, the maximum stress is reduced by 5.75%, to prove the effectiveness of the proposed optimization method. In order to avoid the planar micro gripper holding small objects in the process of clamping the damage or loss, demand forecast and control on holding force is presented. The gauge is integrated in the microgripper structure of sensor integrated design. Produced by clamping force strain is the largest, the pressure generated by PZT strain is the minimum target size parameter of sensing unit the optimization design of piezoelectric actuator input voltage calibration respectively using the least squares method, the relationship between the force and the clamping force sensing element strain. The results showed that describe the relationship between the driving voltage and the strain sensing unit for 3 order number Type, force sensing unit and the clamping force between the strain relationship is linear. The relationship between clamping force and driving voltage between the 3 order polynomial, the formula can forecast and control the clamping force. The proposed calibration method and design ideas for the micro gripper design provides a new ideas. For the planar micro gripper with adhesion problem of micro object in the process of clamping, proposes a release operation method of piezoelectric vibration control based on elastic adhesion theory are proved by the inertial force from piezoelectric vibration can be overcome between the clamping device and micro micro object based on adhesion to illustrate the feasibility. The release operation method. Established dynamic model of piezoelectric micro gripper vibration characteristics by means of experimental method, the model obtains stable driver input amplitude and frequency of voltage conditions. Based on the release of small objects to A micro gripper experimental platform is constructed for the object of micro object release experiment. The experimental results show that the proposed method is feasible to release the operation. At the same time, the experimental results show that the smaller the size of the release of micro object is more difficult, the more need to overcome the inertia by adhesion. In plane micro gripper holding small objects for 2 point contact, can not adapt to the irregular shape of micro object holding operation, the design of a new type of space can hold different sizes and shapes of objects with irregular micro gripper, composed of two mutually vertical clamping chain forming space 4 point contact type clamping clip. A branched chain using two lever principle design, design of groove and the groove on the branched structure, the groove and the lower groove are nested using a drive and drive two branched chain. In order to improve the micro gripper clamp steady And a content, proposed a regression model to establish the relationship between the performance and the structure parameters of support vector machine based on the performance of the optimization based on the model. The design of the space of small screws and small resistance gripping operation experiments holder micro clamp, experimental results show that the micro gripper device can steadily clamp them, to demonstrate the effectiveness of the micro gripper device design and optimization.

【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH-39

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