Research And Design Of Shape Memory Alloy Space Unfolding Structure Actuator

Shape memory alloys(SMAs)are known as one of the most promising smart materials in the 21 st century due to their unique mechanical properties,and have high practical value in the field of new drives.SMA actuator is one of the flexible actuators with larger output force and higher energy density.However,due to the limitation of the accuracy of the current driving response model,this type of actuator has not been widely used.In this paper,based on the research and implementation of spatially unfolded structural actuators,based on heat transfer and driving geometry,the driving response models of two-dimensional bending recovery SMA actuators and three-dimensional SMA spring actuators are studied,and a driving response performance test platform is built for the driving The response model is verified,and an SMA-based spatial deployment structure driver is designed,which can achieve two-way rotational motion output,and has the advantages of light weight and controllable vibration.The main research contents are as follows:First,a two-dimensional SMA bending recovery actuator drive response study.In the first step of this part,the driving response model of Ni Ti shape memory alloy wire with nearly equal atomic ratio is established.In the model,the parameter values affected by temperature are dynamically corrected by introducing the volume fraction of martensite,which greatly improves the driving response.Accuracy of the response model.Furthermore,the influence of section shape on the driving response is analyzed by introducing the average strain of the section,and the influence of wire diameter,initial central angle and driving current on the driving response is also analyzed.Finally,a two-dimensional SMA bending recovery driver performance test platform was built,and the drive response with a diameter of 0.0012 m,a length of 0.01 ?m,an initial central angle of ?/ 6,and a current intensity of 6A was tested to verify the rationality of the model.Second,the three-dimensional SMA spring actuator drive response study.The first step of this part takes the two-way shape memory alloy spring as the research object,and uses the Lagoudas constitutive relation and the spring actuation geometric relation to establish the response model of the SMA spring actuation.Then,based on the model,the influence of the spring wire diameter,initial radius and driving current on the torque output and driving force output,respectively,was analyzed,which provided a reference for the design of the SMA spring driver.Finally,the driving response test platform of the SMA spring driver was built,and the driving response of the wire diameter of 1.0mm,the initial radius of 10 mm,and the driving current of 6 A was tested,and the rationality of the model was verified.Finally,the design and implementation of the SMA spatial deployment structure driver.The first step uses the MATLAB Fmincon function to find the optimal parameter combination that meets the technical requirements,and designs the motion transformation structure based on this group of parameters.Then,based on the stress-strain curve of the uniaxial cyclic loading experiment,the optimal pre-deformation amount and the optimal loading amount of the hyperelastic SMA for vibration reduction were analyzed,and the vibration reduction mechanism for single-vibration to achieve double-sided energy absorption was designed.Then,combined with the motion conversion mechanism and the vibration damping mechanism,a set of driver implementation solutions that meet the requirements of lightweight structure and controllable vibration are integrated.Finally,each part of the drive is processed and the prototype assembly and debugging are completed.A performance test platform is built to test the angular output performance,angular velocity output performance and three-axis acceleration performance,which verifies the feasibility of the prototype.