为了得到一个结构紧凑无摩擦、无磨损且高效率的微进给装置，分析了具有任意角度椭圆凹槽弹性铰链的特性，得到其在不同载荷作用下刚度的封闭解析解，并讨论了弹性铰链的刚度随椭圆长短轴之比s变化时的情况当s由1变化到无穷大时，即由圆形凹槽的弹性铰链经过椭圆凹槽的弹性铰链变化到矩形凹槽的弹性铰链，弹性铰链的刚度逐渐减小，由此引起的应力集中也逐渐减小，但是其运动精度也随之降低此外，还利用有限元的方法对弹性铰链的刚度和运动精度进行了校验

为补偿精密磨床砂轮的振动对加工精度的影响，设计了一台作为磨床辅助进培装置的徽进给工件平台。谊工作平台采用压电陶瓷作为驱动机构，弹性链链作为预紧机构。为了避免压电陶瓷驱动器受到事矩的作用．在压电陶瓷驱动器的顶部和动平台之间加了一个球形接头。利用弹性铰链的顸紧力．实现驱动嚣和动平台之间的赫兹接触。高精度的电容式位移传感器用来测量动平台的实际输出并形成反馈控制系统。为了消除压电陶瓷的迟、蠕变等非线，采用了非线性PID控制算法柬实现微进绔平台的实时控制。采用跟踪徽分器对信号进行跟踪井得到其微分信号，提高了控制系统的鲁棒性。通过计算机仿真了所设计的微进给平台的特性和闭环控制算法的有效性。

研制了一种基于高刚度PZT作动器的超精密定位工作台，其特点是采用弹性铰链预紧和提供工作台侧向刚度，结构简单。动态响应速度快，分辨率高，为防止PZT作动器受到过大弯力作用和动平台弯曲变形，在动平台与PZT作动器间加入弹性缓冲环节和辅助性隔离板，另外，对工作台输入输出特性、静动态刚度和模态振刚、以及受外力作用时产生的静态位移误码差进行了试验研究。试验数据表明，该工作台可作为精密磨床的辅助工作台，极大地提高机床的定位精度。PZT作动器; 精密定位工作台; 动态特性

In this paper, a new type of model for the end milling process is presented considering cutter flexibility, which includes not only the static but also the dynamic deflection of the cutter. According to the basic assumption for a linear elastic body, the force acting on the cutter and its deflection in the milling process are both divided into two parts: the static and the dynamic. By considering the regenerative feedback in the practical milling process, the dynamic milling force acting on a unit length of the cutter is derived. Furthermore, a new kind of dynamic deflection model of the cutter is established. Based on this model, a new set of efficient numerical simulation algorithms are presented. In the mean time, the static deflection of the cutter is also formulated. Finally, the simulation and measurement of the milled surface topography for the end milling process show the feasibility of this model.

In order to achieve active control for improved machining accuracy and efficiency, the control commands will include a substantial amount of high frequency signals. The high frequency command signals may not be sufficiently implemented by the single actuating unit that is the wheel infeed system. To solve this problem, an additional actuating unit will be required to support the workpiece in order to implement small but fast control actions. A high performance workpiece micro-positioning table utilizing a piezoelectric translator under preloaded Hertzian contact has been developed and experimentally tested. The table has shown to have a high resolution of better than 20 nm and a high natural frequency of approximately 579.2 Hz. When implementing a 43.587 ~tm step motion, the acceleration could be up to 33.5 l g, where g is acceleration due to gravity. It is found that when large step commands are applied, the workpiece table would exhibit excessive overshoot due to the separation between the piezoelectric translator and the moving part of the table. This would cause large shock accelerations, seriously affecting the machining accuracy. Dynamic models have been established to describe the table-top motions and the occurrence of the separation, which should be significant due to the wide use of the design of preloaded Hertzian contact. The models have not been examined systematically using an experimental approach. The micro positioning table is briefly introduced and the velocity and acceleration models of the table are presented. Experimental results are analyzed to verify the established models and to validate the findings about the separation. The average modeling error was found to be less than 3 %. This gives confidence in using the system for the fast active control required in high speed machining processes.