Research Of Six-bar Linkage Mobile Robot Driven By Shape Memory Alloy

The six-bar mechanism mobile robot driven by shape memory alloy wire is a new type of mobile device that integrates shape memory alloy sensing,control,driving and planar link transmission.The connecting rod structure converts the reciprocating linear motion of the shape memory alloy wire into the continuous rotary motion of the driving wheel to realize the movement of the robot.This mobile device is not only simple in structure,but also can be controlled by low voltage,and has broad application prospects in the fields of medical equipment and special robots.This paper proposes a six-bar mechanism mobile robot driven by shape memory alloy wire.Based on the structure and working principle of the mobile robot,the parameter design of the driving part of the robot is carried out according to the constitutive relationship of the shape memory alloy;according to the working principle of the planar link mechanism,considering the requirement of the continuous rotation of the robot for the movement amount of the slider the rod length of the six-bar mechanism is determined;the design of the robot drive and control system is carried out according to the driving and control principle of the single chip microcomputer.Based on the SMA constitutive relationship,heat transfer equations and static analysis of the planar linkage mechanism,a team of the multi-field coupled statics equations for mobile robots was established.Based on these equations,the current and temperature changes of SMA wire and the stress of the transmission part are studied.The influence of parameter changes on the deformation of the memory alloy wire in the drive part and the force of the link mechanism in the transmission part is analyzed.The motion analysis model of the six-bar mechanism mobile robot driven by shape memory alloy wire is established,and the calculation formulas of mobile robot position,velocity and acceleration are derived.The changes of the position,velocity and acceleration of the main nodes of the mobile robot are analyzed.The kinematics simulation is carried out by using Adams software.The simulation results are close to the theoretical results.It verifies the correctness of the theoretical analysis.Using the SMA phase transition theory and Newton's second law,the free vibration equations of the driving part and transmission part of the robot are derived,the natural frequencies of the driving part and transmission part are solved,the fluctuation characteristics of the natural frequency of the transmission part are revealed,and the effects of the main parameters on the natural frequencies are investigated.Based on the control system of mobile robot,the design and construction of a mobile robot drive and control platform is done.Based on the robot parameter design,the robot prototype is produced,and the stress and strain performances of the shape memory alloy wire are measured and the working principle verification test of the mobile robot prototype is completed.The test results show that when the heating time and cooling time are both 2s,the mobile robot can move continuously,which verifies the correctness and rationality of the proposed driving principle and structure of the mobile robot.