近年来，随着医学设备、阀、微纳加工、光纤等领域的快速发展，对于高精度机械系统的需求日益增加。由于压电驱动器具有精度高、结构紧凑、功耗低等优点，目前已成为越来越热门的研究课题。根据压电驱动器的运行方式，主要可分为两种模式:谐振模式和非谐振模式压电驱动器。不同模式下的压电驱动器由于其具有各自的功能被应用在不同的领域，但同时这些驱动器也存在一些缺点，主要的缺点就是压电驱动器的输出位移比较小，通常是在微米级别的尺度。为了解决这个问题，我们可以通过使用放大驱动器来提高压电驱动器的输出位移。目前，放大驱动器根据结构划分主要分为: 杠杆式和桥式放大机构。其中，最常见的是杠杆式放大驱动器，这个结构非常简单，但结构体积偏大而且放大比较低。相对的，桥式放大驱动器拥有较高的效率以及紧凑的结构，所以具有较高的发展潜力。但是，因为桥式放大驱动器中的铰链是薄弱环节，在受力较大时可能发生断裂失效的危险，因此需要对结构进行优化设计，以保证放大驱动器在输出较大位移时不会发生断裂，而有限元分析可以从理论计算的角度完成这种优化设计。本文采用静力学分析对桥式放大驱动器在不同结构尺寸和铰链长度下来进行模拟，并且用基于几何关系以及刚度理论模型来计算输出位移和放大比，进而对比理论和仿真结果。结果发现，在调整尺寸比原来的大0.5倍时，可以在不影响到输出位移的情况下大幅减少铰链受到的受力。为了保证结构的稳定性，也对此结构进行不同输入位移测试；此外，在原来结构大0.5倍的条件下，单独再增长铰链长度时，可以在几乎不影响铰链受力的情况下有效的提高放大比。由于振动可能会导致放大驱动器在使用过程中容易失效，对放大驱动器进行了动态分析。由于机械系统运动过程会存在振动现象，所以可以增加弹簧来抑制振动，但是弹簧会使输出位移减少。因此，为了抑制铰链在应用过程中不出现太大的振动并减少弹簧的影响，本文也对弹簧作用下的放大驱动器进行分析，通过来调整弹簧刚度以及输入位移的激励时间两种方式进行动态模拟，为了分析它们对振动幅度和振动时长的影响。结果发现，随着弹簧刚度的增加，驱动器的振动幅度和振动时间并不会降低。在另一方面，在增加激励时间从0.5ms到2ms的时候，放大驱动器的振动幅度会大大减少，振动时间也会变短。因此可以为桥式放大机构的结构尺寸优化提供理论指导，并为放大机构的控制奠定基础。

In the recent years, with rapid development of medical equipment, valves, micro machining, optic fiber and other field, the need of high precision machinery system has been gradually increased. Due to advantages of high precision, compact structure and low power costs; piezoelectric actuator has become a popular research topic. Based on piezoelectric actuator operation mode, it can be classified into two modes; resonance and non-resonance piezoelectric actuators. Due to its unique functions, piezoelectric actuators under different mode could be used in different fields. But at the same time, these actuators also have some drawbacks. The main drawback is that the output displacement of piezoelectric actuator is relatively small, usually in the scale of micron. In order to solve this problem, amplifier actuator could be used to increase the output displacement of the actuator. At present, based on its structure, amplifier actuator can be classified into two major types; lever-type and flextensional-type. Among these, lever-type is the most common amplifier actuator due to its simple structure, however it tends to have larger structure and low amplification ratio. Compared to it, bridge-type amplifier actuator has higher development potential due to it has higher efficiency and compact structure. However, under high stress condition could cause breaking failure at the weak link area around flexure-hinge of the bridge amplifier actuator; as the results, the structure must be optimized in order to ensure the amplifier actuator operate without breaking failure under larger input displacement; while finite element analysis could complete this optimization design from theoretical calculation perspective. In this paper, static analysis method is used to simulate bridge-type amplifier actuator under different structure size and bridge length. In addition, Geometrical-based and Stiffness-based theoretical calculated method are used to calculate the output displacement and amplification ratio; then, the theoretical and simulation results are compared. Based on the results we found that, when structure size is increased to 50% of the original size, we could significantly reduce the stress around the hinge without decreasing the output displacement. In order to ensure the stability of the amplifier actuator, we also simulated this structure under different input displacement. Additionally, by increasing the bridge length under condition of structure size is 50% of the original we found that, the amplification ratio could be greatly increased without significantly influence the stress around the hinge. Due to vibration could easily cause failure during operation of amplifier actuator; therefore, dynamic analysis is conducted on amplifier actuator. As mechanical system could produce vibration during its operation, thus, we could use spring to suppress its vibration. However, the application of spring will reduce the output displacement. Therefore, in order to suppress the vibration of the hinge and reduce the influence of spring on the output displacement; this paper also analyzes amplification actuator under the effect of spring and conducted dynamic simulation by adjusting spring stiffness and the excitation time of input displacement, in order to study its influence on the vibration amplitude and vibration time. Based on the results we found that, with the increasing of spring stiffness, it doesn’t affect the vibration amplitude and vibration time of the amplifier actuator. However, through adjusting the excitation time from 0.5ms to 2ms, the vibration amplitude of amplifier actuator is greatly reduced, at the same time reducing vibration time. In summary, these results will be useful to provide theoretical guidance for the structural optimization of bridge amplification actuator mechanism and establish foundation for the control of amplification actuator structure.