Based On A Flexible Drive Pneumatic Knee Rehabilitation Variable Stiffness Control

CASS Blue Book points out China’s elderly population in2013will exceed200million in2013. The continuous degradation of the joints of older people, people of different sports injuries and accidents leads to the increasing physical disabilities of patients, which provide opportunities for the development of rehabilitation trainer. Because pneumatic compliant actuator is a new type of good flexibility, safe pneumatic drive elements, so it has broad application prospects in the field of rehabilitation medicine. However, the exact expression of its static and dynamic model is very difficult, and fully practical pneumatic muscle actuator needs to solve many problems.The purpose of rehabilitation is to maintain physical function in patients with the greatest degree of limb restores normal movement. Current research is mostly Mckibben pneumatic muscles, and many scholars have studied it, but this is a shorter stroke rehabilitation, generally cannot achieve active training. In active/passive different training phase, we need to take different rehabilitation methods for different patients at different times. This requires the end of the flexible drive having different stiffness in order to provide different damping force or the driving force and the force of the adaptive control can be performed. Therefore, the research works of this thesis are shown as follows:(1) Research of the static and dynamic mathematical model of pneumatic compliant actuator. With pneumatic compliant actuator as an object, we present to stretch the length of the correction factor, and improve static output force model that captures the main factors affecting the output force of pneumatic artificial muscles working length and gas pressure, and then based on the analysis of the pneumatic compliant actuator, we take an experiment. Finally we find the mathematical model to improve is correct by comparing test and model; we establish a dynamic mathematical model for the pneumatic compliant actuator control systems, through simulation and experimental,we analysis the dynamic characteristics of pneumatic muscle systems, which lays the foundation of stiffness.(2) Research of pneumatic muscle stiffness. Based on improved model, we derive the expression of its static stiffness, and analyze the main factors affecting the static pneumatic muscle stiffness; by comparing the model and experiment, we prove the expression of the static stiffness is correct; we give a scientific and reasonable definition of variable stiffness and derive the expression of pressure stiffness with the main factors; The paper establishes a complete mathematical model of dynamic stiffness, through computer simulation and experiment verifies its rationality; With the confrontation installed pneumatic muscle as an object, we find the initial of pneumatic pressure is the main factors affecting stiffness.(3) Research of joint rehabilitation of variable stiffness control. Based on the pneumatic muscles and stiffness characteristics of the study, the paper proposes rehabilitation of variable stiffness joint control strategies and develops adaptive control system based on LABVIEW.