Design And Control Of A Micro Table Actuator Driven By MSMA

Magnetic Shape Memory Alloy (MSMA) Ni-Mn-Ga, which is not discovered until 1993, is one of the newest smart alloys. It has the advantages of shape memory effect, large deformation rate, high concentration of stress and energy, fast dynamic response, excellent linearity and being easily to be controlled. As a result, actuators which are driven by MSMA may become one of the most important driven types in both micro-actuators and precise positioning in the near future. However, almost all of today's researches on MSMA pay more attentions on the manufacture method, micro-mechanism, phase transition and hysteresis characteristic than on its actual applications in domestic. The researches on MSMA actuator has been supported by the project of National Natural Science Foundation of China (NSFC) (50805042)and the project of Natural Science Foundation of zhejiang province(Y10808055). After the introductions of MSMA and the properties of it, an actuator driven by MSMA is designed and lots of experiments has been done to test the machine, aslo the control methods are included.The thesis expounded the development history and the researches all over the world on the new material of MSMA, also the macroscopic deformation and microscopic deformation mechanism in MSMA are included, and then elaborated on the magnetic properties and seven constitutive models of MSMA.The source of the micro-actuators driven by MSMA is magnetism, so it is necessary to build a suitable magnetic loop to meet the need of mechanism. Based on the properties of magnetism and magnetic materials, a tactic of being driven by static magnetic and electromagnetic field is given. The magnetism model used ANSYS suggested that using this method can make the magnetic field adjustable linearly and can also solve the heat problems effectively.The PID control and fuzzy control are introduced. The greatest interesting is the design principles and ways of a Fuzzy Controller (FC). The four parts of a FC, which are Fuzzy interface, Knowledge base, Inference and Defuzzy-interface, are given as an example of a FC model. A model was established to compare the control effects of PID and FC. The final experimental results shows thaa the control effects of FC is better than that of PID.After the researches on basic properties of MSMA, a monolithic construction of actuator made up of MSMA (Ni2MnGa) is made. The work includes the emulations and design of driving magnetic field loops and the magnetic circuits, the manufacture of protector and driving actuator are also involved. At last, many experiments were done to test both of the external and static characteristic, and obtained the ideal curves as we have wanted. The final experimental results show that the designed actuator can meet the requirements well and have an integral capacity mostly thanks to the actuator's structure innovation. And the max displacement of the actuator is 566um, and the strain of Ni2MnGa is nearly by 3%.