Design And Research On Parallel Structure Of Nine Degree Of Freedom For Human-like Rehabilitation

With the continuous improvement of social medical level,the fatality rate of stroke and other diseases has been greatly reduced,but the hemiplegia it brings to patients has gradually become the main cause of threats to human health.Once stroke patients have hemiplegia,the impact on a family is enormous,not only need additional treatment costs,but also need to be cared for by others.For patients,the earlier the rehabilitation training,the greater the probability of recovery,especially in the three months after the onset of the golden period of treatment.Therefore,aiming at the current problem of hemiplegia,a nine-degree-of-freedom parallel structure for human-simulated rehabilitation is proposed.This paper first summarizes the development status of upper limb rehabilitation robots at home and abroad,and points out the research trend of upper limb rehabilitation robots in the future.At present,the research institutes of upper limb rehabilitation robots need to face the following problems: because most of the structures of upper limb rehabilitation robots are in series or in series and in parallel at the same time,the specific analysis and research of parallel-series structures are carried out.As a result,the parallel structure is only a joint of the upper limb rehabilitation institution.Aiming at the problems faced by rehabilitation robots at present,a new type of parallel-series mechanism is designed,which is equivalent to three parallel mechanisms directly connected in series.Firstly,using the theory of constrained helix and the modified Kutzbach-GrU ble formula,the degree of freedom of the mechanism is analyzed.The analysis is divided into integral analysis and hierarchical analysis.For parallel mechanism with three or more layers,the actual helix of each layer will interfere with each other during the whole analysis,and the actual degree of freedom can not be obtained.Therefore,it is necessary to analyze the degree of freedom of parallel mechanism with three or more layers.Firstly,it divides into several layers,and finds out the degrees of freedom of each layer,and adds them to be the degrees of freedom of the whole mechanism.Secondly,the position analysis of the mechanism is carried out,and the forward position solution of the mechanism is solved by using the characteristics of the tandemmechanism;the inverse position solution of the mechanism is solved by exploring the transition layer of the mechanism,and the solution conditions of the inverse position solution of the mechanism are obtained.Finally,the singularity characteristics of the multi-layer parallel mechanism are obtained from the singularity of the mechanism,and the kinematics analysis of the mechanism is obtained by using the influence coefficient theory of the mechanism.It can be seen that the influence coefficient theory of the mechanism is indeed a general method to study the velocity and acceleration of the final moving platform and the various active parts of the mechanism.