Design And Research Series 3-DOF Transfer Assistive Device

According to the seventh national census report,the number of elderly people in my country is increasing,and the proportion of disabled and semi-disabled elderly is also increasing.In addition,the proportion of people with lower limb disabilities in the disabled population in my country is also increasing.Helping the elderly and those with lower extremity disabilities to complete their daily activities and exercise their physical functions will be beneficial to the development of my country’s pension and disability undertakings,and is of great significance in building a harmonious society,promoting the development of social civilization and social stability.In this thesis,30 healthy adult subjects were selected as the research objects,and STS test was carried out under the conditions of different armrest forms,armrest heights,seat heights and with or without knee joint support;the exercise process was divided into three phases.The movement laws and characteristics of the subjects at each phase were analyzed;according to the movement laws of the waist points obtained from the experiment,a tandem3-DOF transfer assistive device was designed,and the trajectory planning of the end effector of the device was carried out;the prototype processing and assembly were completed;The control system was constructed and the prototype test was carried out;by analyzing the waist point trajectory during the prototype test,the human-machine coupling motion mechanism of the device was obtained;finally,the position compensation was performed on the waist point trajectory of the prototype during the human-machine coupling,and the prototype control program was modified to make The human-machine coupling motion trajectory of the prototype basically coincides with the design trajectory,which realizes the secondary control of the prototype and makes it conform to the STS motion law of the human body.The results of the experimental study showed that STS movement was affected by both handrail type and seat height.Using high seat and horizontal handrail could take less time to accomplish STS movement;it also reduced the maximum trunk tilt angle and thus reduce the risk of falling;the time from hindfoot to forefoot peak pressure when using high seat and horizontal handrail was short and subjects could accomplish STS movement easier.Therefore,we proposed an assisted standing strategy that could be applied to the design of assistive devices;that is,choose to use a high seat and horizontal handrail in the assistive device in order to make full use of the arm strength and enable users to more quickly and easily complete STS movements.Through the prototype test verification,the tandem 3-DOF transfer assistive device can realize the design trajectory.