| The vast majority of stroke patients have hand motor dysfunction,which requires rehabilitation training with the intervention of a rehabilitation experts.At present,China is facing the problems of shortage of rehabilitation experts and high costs of manual rehabilitation training.The appearance of hand rehabilitation robots provides the possibility for solving these problems.Early rigid hand rehabilitation exoskeleton robots was gradually replaced by flexible hand rehabilitation robots with low cost,strong flexibility and strong adaptability because of its high cost,poor adaptability and easy to cause secondary injury to the human body.However,at present,flexible hand rehabilitation robots can’t realize the independent rehabilitation of any joint like rigid robots,and because of the small stiffness of flexible materials,it can’t simulate the variable stiffness characteristics of fingers in daily life when lifting and pulling.In order to solve these problems,this paper designs a multi-joint flexible exoskeleton rehabilitation glove with variable stiffness,which realizes the separation and rehabilitation of finger joints through variable stiffness joints and simulate the variable stiffness characteristics of finger pulling action.The content of this paper are as follows:(1)Aiming at the problem of insufficient freedom of movement of flexible exoskeleton rehabilitation robot,a multi-joint fast pneumatic mesh flexible actuator model is proposed.Based on the piecewise constant curvature model,the mathematical model of single airbag bending is established and the parameters are modified.Through finite element simulation,the structure of the air chamber of the soft actuator is optimized,and the shape of the air chamber with the largest bending angle and terminal output pressure is obtained under the same pressure.Compared with before optimization,the bending angle is increased by 35.8% and the output pressure is increased by 32.23%.Combined with bionics in human finger movement,the overall structure of the multi-joint software driver is designed to meet the rehabilitation needs of patients with independent joint movement during rehabilitation.(2)Aiming at the problem of insufficient joint stiffness of flexible exoskeleton rehabilitation robot,a parallelogram joint structure with deformation stiffness based on shape locking is proposed.The design goal of variable stiffness joints was determined by analyzing the joint stiffness requirements of the human hand when lifting and pulling heavy objects,as well as the stiffness changes of the soft drive joint load.The correctness of the structural design of the variable stiffness joint is verified by establishing the kinematic model of variable stiffness joint and static finite element simulation analysis.Through the stiffness analysis of the variable stiffness joint,it is proved that the variable stiffness joint can provide additional stiffness of 1.9～2.5N·m/rad,which can meet the rehabilitation needs of patients with variable stiffness during rehabilitation.(3)Finally,in order to verify the practicality of the software driver structure and the variable stiffness joint structure,a flexible multi-joint finger driver was manufactured,and an experimental prototype was completed by combining the variable stiffness joint and a pneumatic control system was built.Through experiments on the bending angle and fingertip force of a single finger joint of rehabilitation exoskeleton gloves,the whole multi-joint variable stiffness exoskeleton rehabilitation gloves is used to complete various gestures,and objects with different shapes and masses are grabbed and experimented,which proves that the software-driven and variable stiffness joint structure designed in this paper can meet the rehabilitation needs of patients with independent joint movement and variable stiffness during the rehabilitation process. |
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