Research On Footplate-based Gait Training Robot

In recent years,due to the growing aging population and the number of patients with hemiplegia resulting from stroke are increasing,but the personnel shortage of the therapists is becoming more and more severe.The body weight support(BWS)gait training robots combined with body weight support system have caused wide public concern.And the family-oriented gait training and diversified training modes are new trends of the gait training robot technology.Therefore,improving or developing an ingenious structure,multi-functional and low-cost,family-oriented and community-based gait rehabilitation training robot has widespread application prospects.It has a positive and important practical significance for promoting the development of rehabilitation service and medical rehabilitation level,and enhancing the quality of the elderly's and hemiplegic patients' life.The main objective of this paper is to provide natural walking gait training with BWS for the stroke patients and frail elderly by using the footplate-based gait training robot.The detailed theoretical analysis and experimental research are carried out including the mechanism and control scheme of the gait training robot,mechanism dimensional synthesis,gait motion planning,dynamics analysis of human-machine system.Research status of the gait training robots and related fields is overviewed at home and abroad.The mechanism structure,drive mode,working principle and training modes of the existing gait training robots are analyzed.Depending on the motion feature of human walking and the clinical hemiplegia rehabilitation principles,a kind of mechanism scheme of footplate-based gait training robot is proposed considering the ankle and metatarsophalangeal(MTP)joint motion and active unloading weight control.Mechanism characteristics and working principle of this robot are described.The overall control scheme of the robot is determined according to the structural characteristics and operating requirements.The control strategies of passive training and power-assisted training are proposed for the different patients with different degrees of illness and rehabilitation period.On the basis of kinematic analysis and oneself characteristics of gait mechanism,combined with the normal gait and rotation angle laws of lower limbs,the gait mechanism,constraint mechanisms of the ankle joint and MTP joint attitude,and the assisted flexed knee mechanism are dimensional synthesis design to determine the mechanical dimension parameters and the trajectory of straight and curving constraint mechanism.The simulation model of gait mechanism is established by using Matlab toolbox.And the simulation results will verify the rationality of dimensional synthesis and the design feasibility of the gait mechanism.According to gait phase distribution relationship during normal ground walking and the gait mechanism characteristics,a gait motion planning model is proposed for gait training robot,which can achieve reasonable control of gait phase distribution relationship during gait training.The measured trajectory model of the center of gravity(COG)is used as the predetermined tracking trajectory of the human COG during gait training with BWS.A gait planning method of unloading body weight training based COG motion control is proposed to track real-timely the motion trajectory of the COG and ensure the coordinated control between the COG motion and lower limbs gait.Some planning methods of the special gait training,such as a single leg swing training,bilateral legs swing training,etc.are proposed to help the patients intensify training in the initial rehabilitation.The simulation results will indicate the accuracy and feasibility of the gait motion planning methods.In order to study the mechanical properties of human lower limbs and gait mechanism,their mechanical model are established respectively,the generalized forces are solved by using the principle of virtual work,and the dynamics equations of human lower limbs and gait mechanism are established by using Lagrange method.Dynamics model of man-machine system is established by the Newton-Euler method.Take the dynamics model of gait mechanism with load as the controlled object,and the influence on driving performance of the system caused by gait training is analyzed in cases of different unloading forces and different speeds,which are proved the theoretical dynamics analysis is correct.It also provides a theoretical basis for the gait mechanism system optimization,drive motor section and the man-machine system control methods research.At last,the prototype of the footplate-based gait training robot is developed.Based on the Quanser hardware-in-the-loop(HIL)control system platform,the related experimental researches with the prototype are carried out,such as prototype performance test,verification experiment of the gait training planning model and gait training experiments of the robot with the subject.The experimental results will verify whether the designed mechanism scheme of the robot system is reasonable,whether the gait planning and control strategy are effective,and to verify the robot can assist the walking rehabilitation training of the frail elderly and patients with hemiplegia.