| In recent years,the aging of the population and the problems of the disabled have become increasingly serious social problems,among which the number of patients with lower limb dysfunction caused by various diseases such as osteoarthrosis,spinal injury and stroke is increasing.For the elderly and patients,due to the functional decline of lower limbs,muscle strength and balance ability are greatly reduced,which seriously affects the ability of sit to stand transfer and walking,and the necessary sit to stand transfer auxiliary products are especially necessary for the above groups.Therefore,this paper is designed and studied based on the support of knee joint for sit to stand transfer aids,aiming at improving the quality of life of the elderly and patients with lower limb dysfunction,and reducing the pressure of nursing staff.First of all,this paper recruit a number of volunteers,divided into three groups based on knee joint support of the distance between the different feet sit to stand transfer experiments,and three stages to convert sit movement,analysis of different height,gender and weight sit to stand transfer path and kinematics law of subjects,to have the following knee joint support sit to stand transfer auxiliary equipment design provides the basis.Secondly,according to the experimental data,the mechanism design scheme is proposed,the kinematics equation is established,and the activity domain of the mechanism is solved by MATLAB software.The motion trajectory obtained by the experiment is matched with the motion region of the mechanism to verify the rationality of the mechanism design,and the joint angle and rod length are inversely calculated.Finally,a set of dimension values suitable for all subjects and three groups of different height are obtained.On this basis,in order to enhance the safety of the auxiliary tools for sit to stand transfer,a balanced wheel loading mechanism is designed.Finally,the interference of the mechanism is checked by the UG software motion simulation module,and according to the movement trajectory obtained in the experiment.The statics analysis of the mechanism is carried out by using the finite element analysis module to verify the rationality of the structure size and material strength.The experimental results of this paper show that the distance between the feet significantly affects the smooth completion of the sit to stand transfer,and the height and weight are important factors.Different distance between the feet affects the extension mode of joints,the displacement of trunk forward flexion and the distance of body forward tilt.Based on this,the design 2-DOF sit to stand transfer mechanism,including the four connecting rod cross rotary connection of the vertical degree of freedom and the rotating connection parallelogram mechanism as the level of freedom.It can sit to stand transfer according to the predetermined trajectory,at the same time increase the resistance switching device.Through the motion simulation and finite element analysis of the whole mechanism,and finally get the multi-functional sit to stand transfer auxiliary device,walking aid and rehabilitation training is obtained,which can make different rehabilitation training programs according to different rehabilitation periods. |
