Design And Performance Analysis Of A Quadruped Wheel-legged Mobile Robot

At present,countries around the world have listed alien detection as a national strategic emerging industry,and are gradually stepping up their efforts in the research and development of alien detection equipment.Based on 2-UPS/(S+SPR)R closed loop parallel mechanism,a quadruped wheel-legged mobile robot is designed for the complex environment of alien surface.The mechanism has a large bearing capacity and working space,and retains the flexibility of parallel mechanism,so that the robot has a strong ability to cross obstacles.By analyzing the design requirements of space exploration robot,this paper firstly designs the leg structure of the quadruped wheel-legged mobile robot and establishes its overall structure model.Four identical leg structures are mounted on the four sides of the fuselage in a symmetrical distribution.When the robot is in leg movement mode,the wheel is used as the foot end,which can quickly realize the wheel leg switch.The leg mechanism is driven by a servo motor.At the same time,in order to enable the robot to achieve flexible steering in the wheel movement mode,a miniature steering servo motor is set above the wheel.Secondly,the degree of freedom of 2-UPS/(S+SPR)R closed-loop parallel mechanism is calculated by using the spiral theory,and whether there is associated movement in the process of motion is analyzed.The inverse position equation of the mechanism is established by closed-loop vector method and the positive position solution of the mechanism is solved by particle swarm theory.According to the inverse equation of position,the velocity of the mechanism was analyzed and the velocity Jacobi matrix was established.The workspace of the parallel mechanism and the leg mechanism was drawn with the help of SolidWorks,and the specific dimensions of the workspace were obtained with the help of MATLAB.Then,the walking gait of the robot in the leg movement mode is analyzed,and the static stability margin and dynamic stability margin are used to measure the stability of the robot in the process of walking in the static gait.Through qualitative analysis,stability margin and barycenter adjustment,a walking gait with the best stability was selected from 24 kinds of static gait,and the moving trajectory of the foot end was planned by using the complex cycloid method.At the same time,the gait and stability of the robot in the slope terrain were analyzed,the attitude Angle of the robot body relative to the slope was solved,the moving trajectory of the robot's center of gravity was planned by using the five-degree curve method,and the trajectory equation of the robot's center of gravity was obtained.Finally,based on the three-dimensional model of the quadruped wheel-legged mobile robot,the moving process of the robot in the static gait was simulated through SolidWorks to obtain the corresponding step length and step height,and the changes of the center of mass and the driving force of the legs were analyzed.The movement process of the robot in crossing the convex table,gullies and climbing the slope was simulated to determine the obstacle surmounting ability of the robot in various terrains and to analyze the changes of the center of mass of the robot in various terrains.This paper attempts to provide some design ideas and methods for the extraterrestrial exploration robot.