Research On Event-based Synergy Of Upper Limb Joints And Manipulation Of Dexterous Prosthetic Wrist

The multi-degree-of-freedom dexterous prosthesis greatly improves its sports rehabilitation ability,especially the addition of the active wrist,which further improves the dexterity of the prosthesis.However,the patient’s ability to manipulate the prosthesis is relatively weak,and the dexterity of the multi-free holiday limb is difficult to reflect.Traditional methods such as electromyography control can only control a small number of motion modes or degrees of freedom,and are easily affected by confounding factors in the experimental environment and are difficult to clinically quote.Aiming at the problem of dexterous prosthetic wrist control,this paper proposes a control method based on the synergy of upper limb joints,which aims to achieve natural control of the dexterous prosthetic wrist and reduce the patient’s compensatory movement.First,the typical events of human upper limb operation were selected,the experimental procedure was designed,and the corresponding experimental platform was developed.The multi-joint posture data of healthy subjects was collected,the calculation formula of joint angle was deduced,and the joint data set was processed by dimensionality reduction.Visual analysis of the principal components and wrist angles confirmed the synergy of the human upper limb joints,quantitative analysis of the principal components,and discussion of the mechanism of upper limb joint synergy in selected experimental events.Secondly,based on the upper limb movement data set of typical events,the correlation analysis of each joint angle is carried out.Two regression methods,principal component regression and multiple linear regression,were proposed for the results of the analysis,and the two methods were used to perform offline regression analysis on joint data.The analysis results were compared and the multiple linear regression method with better results was selected.A visual comparison experiment of the angle of the wrist of healthy people was designed,and the predicted value and the true value in each typical event were visually compared online.The results show that the method can successfully compensate the wrist movement angle and reduce the compensation angle.The completion rate of each event can reach 100%,and the angle error can be adjusted to within 5°.Then,a dexterous prosthesis wearing system that can be used by healthy subjects was designed and produced.Through it,healthy subjects wear dexterous prostheses on their upper arms,but their wrists can rotate freely.The design and production of the system includes three parts: mechanical structure and control system software and hardware.The functional analysis and detailed design of each part are carried out.The mechanical mechanism is designed and manufactured and assembled and tested;the PCB circuit board is drawn and outsourced;the circuit board is written the lowerlevel computer program running in,completes the construction of the entire system.Finally,in order to verify the actual performance and universality of the wrist control algorithm,an online control experiment of human-like dexterous wrist was carried out.The verification test includes the wrist control experiment of healthy people and the wrist control experiment of disabled patients.By analyzing and comparing the data collected in the experiment,the actual effect of the algorithm is discussed from the aspects of learning speed,completion time,compensatory movement angle and subjective feelings of subjects.The results show that in the selected events,the algorithm can improve the function of the prosthetic wrist to a level close to that of a healthy person.The subjects learn fast and show that it is extremely natural to use and easy to adjust.