Study Of Embedded Control System For Pneumatic Power-Assist Exoskeleton

Exoskeleton is a kind of wearable equipment combining human intelligence and mechanical energy similar to the shell of insect.It can be divided into power-assist and rehabilitation type according to the purpose of use.Rehabilitation type is mainly used to help the patients without exercise capacity to train.Power-assist type is mainly used in the area of minority and disaster relief.The control system is the key part of exoskeleton which is in charge of the acquisition of signal,human-computer interaction and the control of implementation.The focus of this study is the design of control system.The main difficulties are the design and realization of complex control system and the porting of control algorithm.The study begins with analysis of the structure and system demand to determine the system plan surrounding the embedded control system.As the key part of this study,the control system consists of master computer and slave computer.The master computer is an ARM with embedded Linux system to realize the human-machine interaction and rout plan of upper limp and lower limp.The slave computer is a DSP which is used to control high speed valves to control pneumatic muscle.The signal of angle and air pressure sensor is transferred to PC to display and save.The frame of control system is designed according to the demand of system and then choose components.Experiments were carried out to test the control system.Fuzzy PID algorithm and sliding mode algorithm are used to control the signal pneumatic artificial muscle and the sliding mode algorithm is chosen as the final one being used to control the arm of exoskeleton.The study of human-machine interaction was carried for the system.The interaction of upper limb is.controlled by impedance control algorithm.For the legs,the gait can be divided into three kinds and then the weighting sensors and angel sensors are used to identify gait.Finally,Portable gas source system and portable electric system is designed for the free movement of exoskeleton.It is proven that the exoskeleton can work with portable energy system for a while by experiments.