Research On The Strategy Of Climbing Up And Down Stairs For The Lower Extremity Exoskeleton Robot Based On Human Cooperative Control

As a wearable electromechanical auxiliary device,the lower extremity exoskeleton robot has broad development prospects in the fields of medical,industrial and military.Considering the different walking characteristics of different wearers and the complexity of the walking environment,the research on the structural design,gait planning and control scheme of the lower extremity exoskeleton robot has become the focus of research in this field.In this thesis,a set of 8 degrees of freedom lower extremity exoskeleton robot was designed.The gait planning and human cooperative control scheme design was completed based on the walking environment of stairs,so that the wearers could climb up and down the stairs wearing the exoskeleton under the condition of no support,and step with only one foot on each step.The main findings of this thesis are summarized as follows:(1)A set of anthropomorphic lower extremity exoskeleton robots was designed.The robot has 6 active degrees of freedom in the knee,hip and pelvic joints and 2 passive degrees of freedom in the ankle joints.The width and height can be dynamically adjusted to meet the needs of different body wearers.The robot adapts to most of daily walking environments such as flats,slopes and stairs by combining multiple speed,position,attitude and force sensors.(2)A gait planning scheme based on virtual slope method was proposed.When the gait planning of the robot is carried out for the stair environment,the ZMP(Zero-Moment Point)equation is difficult to solve,which makes the center of mass trajectory difficult to obtain.Besides,there is also a problem that the ZMP position is difficult to define in the double support phase.The proposed method can solve both problems by constructing a virtual slope on the stairs and transforming the gait planning of the stairs onto the virtual slope.(3)A human cooperative control algorithm based on barrier energy function was proposed.By designing a barrier energy function,the task space of climbing stairs is divided into a human region and a robot region.In the human region,the wearer can actively adjust the posture,and the exoskeleton remains passive;In the robot region,the exoskeleton dominates the control position and can correct the abnormal gait.Thus effectively improving the wearing comfort and movement stability.The research results of the thesis were verified by conducting experiments with multiple selected subjects.After receiving the initial adaptive training,the subjects were able to wear the designed exoskeleton to successfully complete 10 up and down stairs walking experiments,thus verifying the effectiveness of the proposed strategy.This strategy can effectively improve the wearer's guiding efficiency of equipment and can adapt to more complicated external walking environment.The research results lay a good technical research foundation for improving the applicability of lower extremity exoskeleton robots in complex environments.