Research On Wire-driven Parallel Robot System For Gait Rehabilitation Training

With the aging of the social population,the number of elderly people suffering from diseases such as hemiplegia or stroke is increasing.Such diseases often cause people to lose some of their limb functions.More and more studies have shown that the affected limbs are repeated a lot Sexual rehabilitation exercises can help patients recover their limb function.During the rehabilitation training of lower limb gait,most patients with walking dysfunction cannot bear their own weight on their lower limbs and thus cannot control the loss of balance ability of the center of gravity.Therefore,it is of great practical significance to study a rehabilitation robot that can provide patients with weight loss support to help patients maintain balance.Most existing wire-driven rehabilitation robots use a single wire with only a single degree of freedom in weight reduction control of the human body,and the gait movement of the human body is complex with multiple degrees of freedom.For patients with hemiplegia or stroke,hip support and hip protection are particularly important during gait training.Traditional wire-driven weight loss rehabilitation robots cannot meet the requirements,therefore,this article designed an eight-wire-driven six-degree-of-freedom parallel rehabilitation robot for gait rehabilitation training.Which can effectively play the role of weight loss during rehabilitation training,realize multi-degree-of-freedom movement of the hip,and protect the patient's hip position and posture within a controllable range.The main contents are as follows:(1)Structural design of wire-driven parallel rehabilitation robot.According to the laws and characteristics of human gait movement and the characteristics of the wire-driven parallel mechanism,the overall structural plan of the wire-driven parallel rehabilitation robot was determined.Considering patients with different heights,weights,and different degrees of illness,in order to meet the needs of different groups of people,the whole wire-driven parallel rehabilitation robot is completed with the goal of individual adaptability.At the same time,based on the structural characteristics of the fixed pulley,a pulley group model capable of measuring the change in rope length and wire tension is designed,which provides a basis for the control of the robot.(2)Modeling and analysis of wire-driven parallel rehabilitation robot.First,a wire-driven parallel rehabilitation robot kinematics model is established based on the closed vector quadrature method and Newton iteration method.The correctness of the model is verified through simulation analysis.Secondly,on the basis of static analysis,a Newton-Euler method is used to establish the robot dynamics model,which provided a basis for the subsequent research on wire tension distribution.Kinematics and dynamics models provide theoretical guidance for robot control.(3)Research on workspace analysis and tension distribution of wire-driven parallel rehabilitation robot.According to the characteristics of the singular configuration of the wire-driven parallel mechanism,combined with the wire force constraints,the definition and calculation process of the force control workspace are given,and the force control workspace of the robot is obtained through theoretical analysis and simulation calculation.On this basis,a space safety wall setting for patient protection and a trajectory planning method for returning to safe space are proposed.In addition,on the basis of the dynamic model,and according to the weight loss gait rehabilitation training requirements,the distribution method of each wire pulling force is researched to achieve the weight reduction output effect of the wire-driven parallel rehabilitation robot.The change of the pulling force on each wire during movement has verified the feasibility and effectiveness of the pulling force distribution algorithm.(4)Research on control method of wire-driven parallel rehabilitation robot.Different control targets are formulated according to the recovery of the patient's condition.In the early stage of rehabilitation training,a force/position parallel control strategy is proposed to control the position of the patient's hips while providing the patient with reduced gravity.The simulation experiments verified the double effectiveness of closed-loop control;In the later stage of rehabilitation training,a fuzzy differential-first PID control algorithm is proposed to implement active patient assistance training.Combining the characteristics of the fuzzy control algorithm and differential-first PID control algorithm to perform closed-loop force control of each wire to achieve vertical Requirements for vertical gravity reduction,and the safety monitoring motion control algorithm are designed at the same time,when the patient leaves the safety wall,the patient can be effectively and timely pulled back into the safety wall,thereby ensuring the safety of the patient during the rehabilitation training.(5)Experimental study on wire-driven parallel rehabilitation robot.A wire-driven parallel rehabilitation robot experimental prototype is set up,which mainly includes the design and construction of the experimental system mechanical body,sensor information acquisition system,control system software and hardware,and successively carried out hardware debugging experiments and sensor calibration experiments to carry out the robot's no-load performance Tested and further completed the early rehabilitation training experiment based on the force/position parallel control strategy and the later rehabilitation training experiment based on fuzzy differential advance PID control algorithm,which verified the rationality and structure of the wire-driven parallel rehabilitation robot structure designed.It shows that the proposed wire-driven parallel robot can be used for gait rehabilitation training of patients.