Design And Optimization Of Control System Of Powered Lower Limbs External Skeleton

Powered lower limbs external skeleton is an equipment which people can wear, it can in favor of people to walk, bear loads and exercise muscle power of lower limbs. This equipment combine the advantage of human with that of robots, in order to fulfill the expected motion demands through the cooperation of human and robots. Nowadays, the trend of aged tendency of population has become more and more serious. Powered lower limbs external skeleton is able to help the aged and a group of people who suffer from stroke and lose motion ability to exercise muscle power of lower limbs, recover the activity of muscle, thus improve their life quality.In this master thesis, human lower limbs motion theory is researched and regarded as theory foundation, three-dimensional motion catching system is used to collect and analysis gait data of human's lower limbs and considered as data basis. The structure of powered lower limbs external skeleton is analyzed in two aspects including kinematics and dynamics,the design of lower limb external skeleton control system has been completed and the main content that has been finished in this master thesis as follows:1)Choose motor as power supply through comparing with the advantage and disadvantage of different actuate channel and use servo motor as actuate element.2)According to the control demand of lower limbs external skeleton and performance parameter requirement for actuate element, complete design and model selection of actuate element through considering existing products domestic and overseas.3)The design of sensor system has been completed in this master thesis, it can measure motion information accurately while people dressing equipment to walk and guarantee safety at the same time.4)The control system is designed by the way of closed loop control strategy and the control requirements are fulfilled through constant feedback regulation. The CAN bus communication mode is adopted in this master thesis, it can realize free communication among all of the points, breakthrough the limit that RS485 correspondence can only communicate through master polling. This communication mode improve the real-time and reliability of control system obviously.5)PID control algorithm has been designed, in order to verify the feasibility and the rationality of control system, conduct the simulation of that at the condition of Simulink module of Matlab software. The fuzzy self-adaption PID control algorithm which Combine the fuzzy control and PID control can make further optimization for the control system.In this master thesis, lower limbs external skeleton control system is designed for rehabilitation,it has many features including little overshoot volume,rapid react speed,strong ability of self-adaption and wonderful stability.