Structural Design And Kinematics Simulation Analysis Of Quadruped Robot

In rugged environments,foot robots have an unparalleled advantage over wheeled and tracked robots.The foothold of the foot robot is discrete.In the work space,the appropriate footing point can be arbitrarily selected to avoid obstacles,and the flexible body can be used for all-round movement,so that the stability of the trunk can be maintained even in an unstable terrain.The foot robot can not only better adapt to the unstructured environment,but also make the whole machine more flexible.In this paper,the German Shepherd is used as a biological blueprint for bone anatomy research and analysis.The MCVN Quadruped(MQ)four-legged robot is divided into three modules: skeleton,flexible waist and leg using modular design.Using the topology analysis of flexible waist degrees of freedom and coupling degree,it is found that the four-legged robot flexible waist design principle is met.Compare the advantages and disadvantages of several common driving methods and use the servo motor to drive the whole machine.Calculate the joint torque and speed by using the virtual displacement principle and determine the motor and reducer selection.The Denavit-Hartenberg Matrix(D-H)method and the closed vector method are combined to solve the forward and inverse solutions of the leg kinematics,and the foot end is planned as a polynomial trajectory planning method to verify the correctness of kinematics.The Monte Carlo method is used to draw the foot end working space,analyze the factors affecting the working space of the foot end,and determine the size parameters of the leg mechanism according to the influence of the above factors on the working space.The analytic hierarchy process is used to determine the optimal joint performance of the leg joints,and the whole system is divided into the target layer,the criterion layer and the plan layer.It is best to calculate the joint arrangement of the anterior knee and elbow leg by sorting the total index level and the total order of the hierarchy.Analyze the influence of Walk's gait leg movement sequence on stability margin.According to the self-stability of the whole machine,the order of leg movement is 1-4-2-3.Develop the principle of lifting the trajectory of the four-footed robot's legs,and compare the advantages and disadvantages of several footend trajectory planning such as cycloidal,parabolic,polynomial and joint swing angle trajectory planning.Finally,the polynomial and joint swing angle trajectory planning is selected as the MQ robot trajectory planning,and the trajectory planning driving function graph is obtained.Using Adams software to simulate the motion sequence of 1-4-2-3 in the Walk gait,the driving function simulates the joint swing angle trajectory planning and obtains the centroid displacement and joint moment diagram.The result shows that the whole machine is in X,Y and Z.The centroid displacement in the direction is smooth and there is no mutation,which proves that the movement of the 1-4-2-3 leg movements in the Walk gait is stable,and no rollover and imbalance occur.The joint torque diagram proves that the selection of the motor and reducer at the joint is reasonable and appropriate.