Mechanical Analysis On Soft Pneumatic Arm

With the rapid development of robot technology,more and more robots are used to serve people in heavy industry,light industry or services,and people are freed from a portion of the heavy labor.While traditional rigid robot technology is quite mature,which is applied in a wide range of ways,its quality is great,processing cost is high,however the compatibility with unstructured environment is poor.To compensate for these shortcomings,inspired by nature hydrostatic skeleton structure,soft robot come into being,which is flexible and to perform tasks in an unstructured environment.In this paper,pneumatic muscles are used to fabricate variable stiffness soft pneumatic arm,and its theoretical analysis and experimental research are conducted.Since the pneumatic muscles are driven by atmospheric pressure,the hysteresis characteristic is significantly,the stiffness exhibit non-linear characteristic.Therefore,we designed an experiment to test the stiffness of pneumatic muscle,fitting the experimental results,obtaining the relationship between the stiffness of homemade pneumatic muscle and the air pressure in them.Not difficult to find,pneumatic muscles can be seen as variable stiffness of the spring as the structural parameters are unchanged,which possesses non-linear relationship with pressure.Based on the theory of continuity and equal arc assumptions,software pneumatic arm bending motion in space are simplified into equal arc model,and then,kinematics and differential kinematics model of the arm are analyzed,and the relationship between arm position in space and the length of muscles is analyzed.MATLAB software is used to simulate the motion space of the arm and the velocity of the end of the arm.Meanwhile,the static model of software pneumatic arm is established in this paper,making it clear that when the arm at a spatial position is in equilibrium,the filling pressure in each pneumatic muscle is need.The influence of pneumatic pressure within the elongation muscle on the pneumatic pressure within the contractile muscle is studied.Finally,the experimental platform is set up to analyze the dynamic characteristics of the pneumatic arm,laying a good foundation to establish dynamics of models.This study can be applied to software robot development,and provide some reference.