Research On Stability Criterion Of Power-assisted Robot For Lower Limb Exoskeleton

The walking-assisted lower extremity exoskeleton robot is a wearable assisting equipment,which integrates multi-modal information instropection system.It can be used for assisted walking,gait rehabilitation training,weight carrying and so on in outdoor areas without roads.At present,the aging of our population and the occurrence of motor nerve disorders are gradually increasing,especially the increasing number of lower limb motor dysfunction,which leads to the abnormal operation of human motor function.More and more old people and disabled people suffer from lower limb physiological function degradation.The lower limb exoskeleton robot will become one of the most important and promising intelligent devices because of its working characteristics of assistingwalking.In this thesis,an exoskeleton robot of lower limbs is optimally designed by electro-hydraulic servo drive.By using gait balance theory,a mathematical model of walking-assisting balance is established,and a human-robot interaction perception channel is constructed by means of perceptual interaction technology.Multi-modal information such as plantar pressure and centroid posture is fused to judge walking-assisting stability,which provides a criterion and verification method for the exoskeleton robot to stabilize its supporting boundary.Specific research contents are as follows:(1)Research on the mechanism of human-robot cooperative motion.Using anatomical theory,the joint structure of human lower limbs is simplified,gait phases are divided,motion characteristics are analyzed,exoskeleton body structure design is optimized,human-robot coupling interaction force is reduced,joint drive is matched,and man-machine cooperation effect is optimized.(2)Kinematics and dynamics analysis of exoskeleton robot.By using D-H parameter method and Newton-Euler equation iteration method,a simplified dynamic model of seven links was established,and the joint angle,angular velocity,driving torque,power and other parameters of exoskeleton robot were calculated.The simulation experiment was completed by ADAMS,which verified the effectiveness of exoskeleton joint structure design and electro-hydraulic servo drive configuration.(3)Research on stability discrimination method based on multi-modal information fusion.This thesis analyzes the limitations of zero moment point in judging the stability of exoskeleton robot’s walking aid,establishes the model of exoskeleton’s human-robot cooperation walking aid,fuses multimodal information such as centroid posture and plantar pressure,and provides a basis for judging the stability of exoskeleton’s walking aid process,and studies and establishes a judgment method based on stable support boundary.(4)Experimental study on discrimination of walking stability.Adams simulation and walking aid experiment of exoskeleton robot were carried out respectively,and the experimental scheme of human-robot cooperation walking aid was designed,and the stability experiment of human-robot cooperation walking aid was carried out.The experimental data were compared and analyzed,and the experimental results showed that the stability criterion was effective.For the lower limb exoskeleton assisted robot,this thesis studies the mechanism of human-robot cooperation,optimizes the design of ontology structure and joint drive,analyzes its kinematic and dynamic characteristic parameters,fuses multi-modal information including centroid posture and plantar pressure,studies and establishes the stability criterion,and conducts Adams simulation and walking stability experiment to verify the effectiveness of the stability discrimination method,which lays a research foundation for the subsequent exoskeleton anti-fall control and effectively promotes the intelligent level of the lower limb exoskeleton robot.