【作者】 夏刘可；

【导师】 王凤翔；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2008， 硕士

【摘要】 在现代工业中,对体积小、重量轻和高力能密度运动及位置控制直线执行器的要求越来越高。现在,越来越多的功能材料可以用于产生机械运动,利用新型功能材料制造各种执行机构的研究受到人们的广泛关注。形状记忆合金(SMA)因大功重比、集驱动传动和传感于一身、变形大等优点使得它在微小型应用领域具有独特的应用前景。本文首先总结了SMA的晶体结构和变形机理,给出了SMA的马氏体结构和本构关系。对50.8%Ni-Ti材料进行静态实验研究,分析了SMA材料的应力、应变、温度之间的关系,以此为理论基础,对不同结构内嵌式记忆合金执行器形变模型与性能作了研究。其次,分析了Ni-Ti形状记忆合金弹簧的通电电流、变形速度和位移、相变温度之间的关系,并对差动式形状记忆合金弹簧驱动器的工作原理做了阐述,设计制作了并列型差动式形状记忆合金执行器,选择电脉冲加热和液体冷却方式驱动。实验得出,该执行器输出力和位移比较大,且机构简单控制方便,通电电流在不破坏材料晶体结构范围内,位移及变形速率随着电流的增大而增加,加上合适的冷却措施,可作为不同频率要求的驱动源。差动式SMA执行器通过结构上的创新,不仅大大提高了SMA执行器的工作频率和输出力矩,而且有效减小了运行功耗。最后,设计了一种并列型差动式SMA执行器驱动的无阀泵系统。差动式SMA执行器可以有效减小材料的非线性和宽滞后带来的影响,提高工作频率和输出力。本文详细论述了差动式SMA执行器驱动的无阀泵的结构和运行原理,泵体结构的最优参数设计,设计并制作了一台差动式SMA执行器驱动的无阀泵实验样机,对样机进行了流场有限元分析,并进行了初步的实验研究。分析和实验结果验证了差动式SMA执行器驱动的无阀泵的可行性。更多还原

【Abstract】 Precision motion and position control actuators which can provide greater forces and torques within given volume and weight are in great need in modern industry. Nowadays, more and more functional materials can be adopted to generate mechanical moving. New kinds of actuators based on smart materials are paid more attention to. NiTi Shape Memory Alloy would have unique latent application in miniature or small scale robot because of some merits, such as great power rate, integration between sense and actuators, large strain etc.In this thesis, the crystal structure and shape variation mechanism of SMA are analyzed. The Martensite structure and the constitutive relation of SMA are presented. In this dissertation some main research works are presented as following: 50.8at%-Ni-Ti memory alloy is chosen for the best general property by the comparison with other several present smart materials in actuating properties. The relationships among strain, stress, and temperature and phase transformation of shape memory alloy (SMA) are presented as base theory of development and application of embedded SMA actuator.Next, the relationships among current, strain rate, displacement, phase transition temperature and working principle of the differential SMA spring actuator are discussed, and the operation principle of the differential SMA actuator is described also. A parallel-type differential SMA actuator are designed and made and its characteristics are studied, PWM electrical heating and liquid cooling are chosen for actuator in order to get best operation frequency for differential actuators. The experiments showed that, the actuator can output great force and displacement with a simple structure and control system. Displacement and deformation rate rise with the increase of current in a certain range. The differential SMA actuator with a special structure can operate on higher frequency, provide greater force and have a high efficiency.Finally, in this thesis, a valveless pump driven by the parallel-type differential SMA actuator is proposed. The design principle of the differential SMA actuator and the one-way flow mechanism and structure design of the valveless pump has been analyzed. A prototype and the control system have been developed successfully. The analysis of flow field has been finished, and the preliminary test has been taken. The feasibility of the operation principle and design method of the valveless pump driven by the SMA actuator has been proved by the analysis and test results.更多还原