| With the development of social economy,China has gradually entered the aging population.The incidence rate of stroke increases year by year,and is becoming younger and younger.However,due to the improvement of medical level,the mortality of stroke patients is gradually decreasing,but the disability rate is still very high.Limb dyskinesia is a common sequelae in post-stroke patients,including hand dysfunction.Aiming at patients with hand dysfunction,this paper develops an exoskeleton rehabilitation manipulator.In terms of structure,the rehabilitation manipulator is driven by thin flexible cable and steel cable to simulate the flexibility and elasticity of human muscles,so as to ensure safety and comfort.At the same time,the whole structure realizes the design of lightweight and easy to wear;In terms of control,the rehabilitation manipulator has an active and passive rehabilitation mode,in which the passive rehabilitation mode can achieve accurate position grasping and strength grasping,and the active rehabilitation mode can achieve impedance movement with different degrees of resistance.At the same time,it also has safety protection and control functions,mainly including speed safety protection,position safety protection and emergency stop safety protection.The main research contents and conclusions of this paper are as follows.Firstly,in order to realize the ultra-lightweight design of the rehabilitation manipulator,the hand structure and the driving structure are divided into two separate modules to design,and the fingers are driven by thin flexible cables to ensure that the humanmachine force has a muscle-like force.Elasticity;at the same time,in order to prevent the driving cable from bending and deforming in a wide range when pushing the fingers to bend,the guide blocks and the driving blocks are specially designed.In order to ensure the smooth movement of the drive cables in the proximal/middle phalanx guide blocks and to prevent gaps during fixation on the distal phalanx drive blocks,the guide blocks for each finger and the guide holes for the cables of the drive blocks are designed respectively.Secondly,in the passive rehabilitation mode,in order to realize the position control and grip strength control of fingers,two control modes of empty grip and force control are established respectively.The empty grip mode is to control the bending position of the finger by controlling the feed rate of the driving flexible cable by analyzing the relationship between the bending degree of the finger and the feed rate of the corresponding driving flexible cable;In the force control mode,the grasping force of the patient’s fingers is always maintained within the allowable error range of the expected force through the force control algorithm.The force control algorithm realizes the regulation of the grasping force of the hand by constantly changing the expected feed of the driving flexible cable,and the expected feed of the driving flexible cable depends on the difference between the actual grasping force and the expected force.Then,in the active rehabilitation mode,in order to make the patient move the rehabilitation manipulator autonomously,an active control algorithm is established,which is mainly composed of motion intention judgment algorithm and impedance motion control algorithm.In the process of patient movement,in order to eliminate hand jitter and make the system misjudge the patient’s movement intention,the system adds volume deviation;In order to eliminate the noise of the system data and enhance the stability of the system,the second-order low-pass filter is adopted.Finally,the human-computer interaction interface of the active and passive rehabilitation motion control system is developed based on MFC.The empty grip mode,force control mode,active rehabilitation mode and safety protection of passive rehabilitation are tested respectively to verify the effectiveness,reliability and safety of the function. |
