| At present,problems such as low degree of freedom and small range of travel exist in ankle rehabilitation robot,which leads to insufficient rehabilitation training of ankle rehabilitation robot at the ankle.In order to solve this problem,an ankle rehabilitation robot based on 3-PRPS parallel mechanism is designed in this paper.The main research work is as follows.Firstly,the parallel mechanism configuration of ankle rehabilitation robot is determined.The design principle of ankle rehabilitation robot is defined through physiological structure,movement mode and motion parameters of ankle joint.Based on spiral theory,the design and selection of branched chain configuration were carried out,and the ankle rehabilitation robot was identified as a 3-PRPS parallel spatial mechanism.Based on the modified K-G formula and spiral theory,the degree of freedom of the mechanism is analyzed and a three-dimensional model of 3-PRPS parallel ankle rehabilitation robot is established by using Solid Works software.Secondly,kinematics calculation of ankle rehabilitation robot is carried out.The position coordinate system is established according to the initial state of the parallel mechanism and the transformation relationship between the dynamic platform and the static platform is established by the position and attitude transformation matrix.According to the position relationship between the branches,the position inverse kinematics calculation based on geometric analysis method and the position forward kinematics calculation based on numerical method are carried out for the moving platform.The speed Jacobian matrix and acceleration Hessian matrix of input and output of parallel mechanism are established by closed-loop vector method.Using MATLAB software,examples of inverse and forward position solutions were calculated for the parallel mechanism platform.Finally,kinematics simulation analysis of ankle rehabilitation robot is completed.The posture GUI interface of 3-PRPS parallel ankle rehabilitation robot was established by using MATLAB software.By defining different dynamic platform posture parameters,the overall posture and component parameters of the rehabilitation robot were obtained.According to the constraints of components of parallel mechanism and kinematics solution model,the workspace of parallel mechanism is established and analyzed by MATLAB software.A virtual prototype of 3-PRPS parallel ankle rehabilitation robot was built using ADAMS software.The kinematic analysis was verified by inverse kinematic simulation analysis.Based on the requirements of isokinetic rehabilitation training,a composite function of rehabilitation training motion is created and kinematic simulation analysis of rehabilitation training under different conditions is carried out.The results show that the motion requirements of ankle and foot rehabilitation robot can be met. |
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