Design And Performance Of SMA-Based Soft Crawling Robot

As a hotspot in robotics research,soft robots have important application prospects in detection,medical treatment and other fields attributed to their strong environment adaptability and high security of human-computer interaction.Based on the application study in performance of the new smart material shape memory alloy(SMA),a SMA-Based soft crawling robot was developed in this paper,then the simulations,numerical analysis and experimental research on the components and robot prototypes were carried out.The results will provide theoretical basis for the design of SMA-Based flexible actuating apparatus.According to the law about conservation of energy,the heat transfer model of SMA wires was established.The temperature-rising characteristics were analyzed by Matlab simulation,and the corresponding experiments were carried out to verify the obtained results.Meanwhile,the experiments aiming to driving performance of SMA wires were carried out.The results show that the SMA wires driving force increases at first,and then tends to be a steady value as the voltage is kept constant.Both the rising rate of the driving force and its steady value increase with the the voltage,whereas there is a upper limit for this steady value.When the current is turned on and off,the SMA driving force increases and decreases correspondingly,which reflects its good two way shape memory effect.Based on the principle of bionics,two kinds of soft crawling robot system schemes are proposed.Comparing and analyzing the structural stability and scheme feasibility of above schemes,the SMA-Based Soft Crawling Robot is selected as the research object.Then the telescopic module,cavity actuator and friction gastropods which constitute the main structure of the robot are designed.At last,the mould of telescopic module and cavity actuator are designed according to the silicone casting technology.Finite element simulation analysis of telescopic module and cavity actuator is carried out by ABAQUS,to study how the material hardness and key structural parameters of telescopic module affect its deformation,structural optimization of cavity actuator is finished in the meanwhile.The results show that the smaller hardness of telescopic module material and the bigger corrugation depth h,the better deformation performance of telescopic module.And the value of the liquid flow diameter d has little effect on telescopic module deformation performance.The cavity structure has a great influence on cavity actuator shrinkage performance.When the inner section of cavity actuator is optimized to be an ellipse that with 17 mm long axis and 15 mm short axis,the shrinkage performance of the cavity actuator is the best.Combining the 3D printing technology and silicone molding process,the components of the soft crawling robot are manufactured,and the performance experiments of cavity actuator and expansion module are carried out.The experimental results show that the cavity actuator can produce overall shrinkage under the action of SMA wires,and in the range of SMA wires response voltage,the bigger the voltage,the better the shrinkage performance.The propulsive force and the axial deformation of expansion module increase linearly with the increase of the liquid volume.Then the robot prototype experiment is carried out based on the above research.And the experiment results show that the SMA-Based Soft Crawling Robot can achieve ideal crawling motion.Subquently,the robot structural rationality and driving mode feasibility are verified.