Design Analysis And Training Planning Of An Ankle Rehabilitation Mechanism

The ankle joint is one of the important joints in the body and is the energy hub that supports the body’s weight and sustains daily life and movement,but it is also the joint most susceptible to damage from weight or external impact.With the rise of the national fitness movement and an ageing population,traditional medical rehabilitation methods are no longer able to meet the increasing demand for ankle rehabilitation training year on year.As a result,rehabilitation facilities combined with medical-industrial rehabilitation have become a research hotspot in recent years at the intersection of medicine and engineering.In this paper,an ankle rehabilitation mechanism based on the 3-UPRU/S parallel configuration and its foot fixation and quick release components are designed to address the rehabilitation needs of the ankle joint,and its motion performance and training planning are investigated.Firstly,from a physiological point of view,the skeletal structure,type and range of motion of the human ankle joint were investigated,the medical mechanism of ankle rehabilitation was clarified and the corresponding design indexes and principles of the rehabilitation mechanism were formulated;on this basis,a new configuration based on the 3-UPRU/S parallel mechanism was proposed and the corresponding kinematic analysis was carried out with the aid of MATLAB to initially determine the correctness of the configuration.Secondly,on the basis of the configuration design,the transmission method and component selection of the drive support chain were clarified,and the specific structural design of each part of the rehabilitation mechanism was completed using UG;to further improve the safety of the rehabilitation process,the foot fixation and quick release components were designed;a modal analysis of the entire rehabilitation machine and the actuator was carried out using Patran ＆ Nastran in order to avoid possible resonance phenomena when driving the rehabilitation mechanism subsequently.Again,in order to eliminate the influence of the non-coincidence between the physiological centre of rotation of the ankle joint and the centre of rotation of the rehabilitation mechanism on the rehabilitation training planning,a human-machine interactive rehabilitation training simulation model was established,and its positive and negative kinematic analysis was simulated and verified to ensure the correctness of the kinematic analysis and simulation model of the mechanism;The rehabilitation of plantarflexion/dorsiflexion of the ankle was planned and the rehabilitation process of rotation around the centre of the human ankle was planned accordingly,and an optimal training planning scheme was obtained;Then,through the biomechanical simulation conducted by the rehabilitation training model in accordance with the above training plan,the activation curves of the muscles around the ankle joint during the rehabilitation process were obtained,and the rehabilitation effect and feasibility of the training plan were evaluated;Further,through inverse kinematic simulation of the rehabilitation training model,the drive functions of the actuators of the rehabilitation mechanism were obtained for plantarflexion/dorsiflexion training of the ankle according to the optimal training plan,laying the foundation for subsequent experimental verification and optimal control.Finally,the prototype of the ankle rehabilitation mechanism was assembled and the test system was built;the motion performance,limit stroke and repetitive positioning accuracy of the actuators were tested to ensure that they met the motion specifications of the mechanism;the coordinate measuring system was built with the aid of an Akcome binocular measuring camera and a coordinate matrix of multiple targets was used to replace the human ankle in the training plan;the actual reachable angle of the rehabilitation mechanism was tested and the rehabilitation training plan was compared before and after optimisation,thus verifying the feasibility of the ankle rehabilitation mechanism designed in this paper and the rationality of the corresponding rehabilitation training plan.