| Along with our country entering an aging society,the percentage of people over 60 have reached 17.3% of the total population in 2017,the proportion will reach 34.9% in 2050,and elderly care need to occupy a significant portion of the medical care resources,so the research of walker for the elderly walking and living receives extensive attentions.Moreover,the disabled rate of cerebral apoplexy and other cerebrovascular diseases is high,and the aging of population increases the number of people disabled by cerebrovascular diseases year by year.In addition,traditional treatment methods have such problems as low rehabilitation efficiency,high cost of physiotherapists,large training intensity and inconsistent training effect.Combined with the above two needs,the rehabilitation walker that can help the elderly or stroke patients with walking assistance and rehabilitation training in daily life,help them regain independence and improve their quality of life,is the current research hotspot of lower limb rehabilitation robot.However,the relevant robots developed at home and abroad cannot combine walking assistance and rehabilitation training commendably at present,pay little attention to the pelvic movements and pelvic balance control,and lack of theoretical analysis and technical guidance of force field assistance technology.Therefore,it is of great significance to develop a rehabilitation walker that assist the elderly and stroke patients in rehabilitation training and daily life,which can promote the development of rehabilitation medicine in China.To optimize the control interaction force,the modeling of human bipedal walking is carried out firstly in this paper,through the contrasitive analysis of gait motion and pelvic movements between normal adults and patients,summed up the root cause of abnormal gait and basic needs of rehabilitation training.Then,based on the demand analysis,the prototype of rehabilitation walker is designed,and the performance analysis of the robot is analyzed through the kinematics modeling.The flexible modeling of joints is conducted,and the rigid dynamics of the robot is derived.The force control algorithm and trajectory planning algorithm are presented based on the proposed model,which provide the foundation for man-machine interactive control,the clinical application of rehabilitation robot and related key problems in the field of rehabilitation engineering research.The research work is as follows:1.based on the characteristics of human physiological mechanism and gait analysis,established the human bipedal kinematics and dynamics model(17 bars and 34 Do Fs),the pelvis motion analysis and abnormal gait analysis are derived,and then obtained the joint force wrench based on motion parameters,such as mass,inertia,joint position,speed and acceleration screw,then the Matlab/Simulink software is employed to verify the validity of the model.Based on the user's demands and data analysis,the targets for gait training and balance training in patients are proposed,which provide the references for the interactive control.2.According to the actual requirements of rehabilitation training,this paper proposed a rehabilitation walker to achieve natural pelvic movements,presented the characteristics and working principle of the mechanism.The kinematics of the robot were established to analyze the kinematics performance of the robot,such as workspace and capability map,which provided the foundation for the subsequent rigid body dynamics modeling.3.The Newton-Euler recursion equation of the robot is established to study the assistive technology of force field,and the process of solving the forward-inverse dynamics solution is given.Based on the modeling of joint deformation,the mechanical model of pelvis is established.Combining rigid body dynamics,joint deformation model and comprehensive friction force model,the control algorithm of body weight support mechanism,the feedforward control algorithm of mobile platform and the training trajectory planning algorithm of pelvic support mechanism were proposed,which provided theoretical basis for the interaction force control strategy of the robot.4.The experiments with normal subjects and contrast experiments with simulate patients were conducted in the end.The maneuverability of the robot,the validity of intention recognition and the validity of interaction force control were verified through the “?” path tracking experiment,offloding force control experiment and assistance force control experiment with normal subjects.This was followed by the tests with the volunteers equipped with leg splint to simulate the patients.The experimental results verified the effectiveness of the dynamic model and the proposed force control algorithm,which indicate that the robot is capable of the balance ability rehabilitation and pelvis control of stroke survivors.The fundamental research on rehabilitation walker and the assistance technology during human-machine interaction are carried out in this paper.The correctness and effectiveness of the proposed method are verified by dynamics simulation software and robot experiments.The research results can be applied to the human-machine integration control and optimization of the flexible robot,which is helpful to promote the research on the assistance technology in the rehabilitation training. |
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