Design And Optimization Of Lower Limb Kangfu Robot Based On Hip Joint Trajectory

China is a country with a large population,but it is also a country with a large elderly population.With the increasing of people's age,the human body function will gradually deteriorate,which will lead to the inability to independently sit and stand and walk.At this time,Kang Fu robots are needed to assist the elderly to complete basic daily actions and improve their quality of life.At the same time,with the increasing of people's age,the probability of suffering from senile diseases gradually increases.Stroke is one of them,which can lead to limb movement disorders,such as unable to walk independently and unable to sit and stand independently.Medical research shows that necessary physical rehabilitation can help patients suffering from stroke to recover their limb functions and further help them recover.However,the number of rehabilitation doctors in China is too small to undertake the physical rehabilitation of all patients.Kangfu robot can help rehabilitation doctors to recover patients,thus effectively reducing their working pressure.Kangfu robot can help the aged with weakened body function to complete simple actions and ensure their basic life.Kangfu robots can also help the elderly with limb movement disorders caused by stroke and other elderly diseases to carry out scientific and efficient physical rehabilitation and restore their body functions.The design of Kang Fu robot needs to consider many aspects such as humanoid and lightweight.In this paper,we need to find the motion track of the hip joint when healthy people sit and stand and walk.Firstly,a lower limb segment model corresponding to sitting and standing and walking is established,then the motion data of the limb segment is measured by an inertial sensor,and the length of the limb is measured by a caliper,and then hip joint trajectory equations in the sitting-standing process and walking process are respectively established,and finally the motion trajectory of the hip joint is obtained and normalized.According to the motion track of hip joint,a Kang Fu robot is designed,which mainly realizes two functions: assisting sitting-standing and assisting walking.When assist a human body to sit and stand,that rear driving wheel is loc and keptmotionless,the front driving wheel and the posture adjusting motor move simultaneously,so that the motion track at the saddle is matched with the motion track dure the sitting and standing,and human-like assistance is realized;When assisting a human body to walk,the posture adjusting motor does not move,the lower arm of the rear stay rod and the upper arm of the rear stay rod are kept fixed,and the front driving wheel and the rear driving wheel move forward at a differential speed,so that the motion track at the saddle is matched with the motion track of a healthy person when walking,and the humanoid walking assistance is realized.After the functional design of the mechanical structure is completed,the stability of the mechanical structure is verified by using the D'Alembert principle.After completing the functional design and stability verification of the mechanical structure,the motion parameters of the power source are calculated.On the basis of the human sitting-standing trajectory,the motion parameters of the posture adjusting motor and the front driving wheel are calculated and verified by simulation.Based on the human walking track,the motion parameters of the front drive wheel and the rear drive wheel are calculated and verified by simulation.Finally,the lightweight design of mechanical structure is carried out.Firstly,the mechanical structure's stress condition is analyzed to determine its limit stress state,i.e.sitting posture state.Then the mechanical structure is topologically optimized,and the mechanical structure is correspondingly improved according to the results of topology optimization.For the improved mechanical structure,the minimum mass is taken as the goal,the allowable stress of the structure and the maximum displacement at the saddle are taken as the boundary conditions,the size optimization process is established,and the lightweight of the mechanical structure is completed.