Theoretical Analysis And Experimental Research On The Automobile Door Lock Actuator Drived By Shape Memory Alloy Wire

With the improvement of electrification and intelligent level, the car is gradually become a collection of various kinds of electromagnetic drive, and traditional electromagnetic car locks drive have a lot of problems, such as big volume / quality / impact noise, severe electromagnetic interference etc. In order to solve these problems, and improve the level of intelligent car door lock system,this paper proposes an automobile door lock actuator drived by shape memory alloy wire that make use of Shape Memory Alloy wire as a driving element which mainly use Shape Memory effect and superelasticity of SMA.From the drive form, the traditional drive consists of electric drive, hydraulic and pneumatic drive. compared with them, the working principle of SMA alloy drives and design are very different,the traditional drive input energy by the outside world,through complex structure into a displacement or reverse movement to do mechanical work, but a driving force of the SMA actuator is the result of alloy internal solid transformation, what it need is only through the proper way to heat alloy, driven purpose can be realized. comparatively speaking, SMA actuator has the following characteristics : 1) power/weight ratio is big; 2) simple structure; 3) no noise pollution; 4)sensing function; 5 low driving voltage.This paper introduces the research development and application of SMA actuator. Then the basic characteristics of shape memory alloy wire and mechanical properties are analyzed and experimentally researched. On the SMA wire tensile test, we obtain the environment temperature/ cycle times/ strain amplitude/ loading rate and prestrain on the mechanical behavior of SMA wire. The weathering test of memory alloy wire results show that SMA wire has good weatherability. The differential thermal analysis was carried out on the SMA wire test which make us gain the SMA phase transition temperature and obtain some other basic parameters of shape memory alloy wire. In order to obtain the different forms of SMA actuator and improve its reliability and working life, this paper respectively designe offset type and differential type shape memory alloy drive and protection circuit. In order to get the drive output characteristic,this paper applies the memory alloy double flag constitutive model which is written into VUMAT subroutine,then uses ABAQUS software for finite element simulation and analysis, the results show us the basic properties of the SMA(Shape Memory Alloy) actuator.This paper also introduces atemperature- current- time constitutive model of SMA, then the part of the constitutive model was written into program code which canbe calculated by Matlab, temperature and time curve can be obtained, the frequency respo nse can be obtained indirectly drives. In order to obtain the new wire car door drive system performance parameters, and compared with the results of simulation, this paper set up the drive mechanics performance test device. The results show that the wire shape memory alloy actuator not only can replace the electromagnetic motor drives, also can open the car door locks. It improve the intelligent level of the car door lock system and laid a certain foundation for the application of shape memory alloy drive in the car.