Bionic Robot Foot-Ground Interaction Mechanism And Experimental Research

In some complex environments, environmental adaptability and flexibility of traditional mobile platforms can not meet the requirements.After millions of years’ evolution, quadruped animal with a strong environmental adaptability, gradually become dominant terrestrial organisms, and researchers of all over the world have started to study foot mobile platform. Legged robot can complete combat, explosive ordnance disposal and goods transportation work in the mountains, swamps, sand and other harsh environments. The foot end as the only carrier between robot and ground environment, determine the flexibility and load capacity of the robot.This paper took quadruped robot’s foot end mutual process with the ground for the research object to expand the research work.This paper reviewed the current general situation of the foot robot research and the foot end of quadruped robot, then analyzed the current important issues in the research field of foot robot. Meanwhile, thesis pointed out the importance of research in the field of quadruped robot foot end to the stability and gait control of multi-legged walking robot. The main content of the study:the theoretical model of quadruped robot’s foot end interaction with the ground was established, a bionic mechanical leg was designed based on the principle of bionics, manufacture of bionic equinus with3D printing technology, Analysis of the kinematics and dynamics of bionic mechanical leg, Development of a foot-terrain testing platform, And experiment research of foot-terrain interaction was carried out.The current four-legged robot foot end which was developed by various countries can be concluded to four categories:flat-shaped foot end, a cylindrical (semi-cylindrical) foot end, spherical (hemispherical) foot end and irregular foot end (including bionic foot). Based on the elasticity, ground environment which the quadruped robot encountered divided into hard ground and soft ground. According to the study on terrestrial mechanics theory and kinetic theory of containing clearance ball hinge motion pair, their foot-terrain interaction models of the former three typical foot end, were established in two kinds of ground environment, and these models deduced the expression of the vertical force Fn and the lateral force Fτ.A foot-terrain testing platform was built in this paper. Meanwhile, taking quadruped mammal for the research object to expand bionics research work, a biomimetic mechanical leg with two degrees of freedom was designed.Kinematics researches of biomimetic mechanical leg were launched by using D-H method. And, inverse kinematics and Jacobi matrix were given for the developed biomimetic mechanical leg. To get driving torque expression of two joints, kinetic were conducted based on Lagrange dynamics equations.Trajectory planning was carried out on the foot end of the quadruped robot, and modeling analysis in ADAMS. On foot-terrain testing platform, the experiments of hemispherical foot and bionic Horseshoe end interaction with mud, and bionic Horseshoe end interaction with soft ground were made. Compared and analyzed the similarities and differences of the three areas that hemispherical end and bionic foot horseshoe in its support, propulsion and mechanical legs torque of the robot, Synoptically, the bionic equinus was better than hemispherical foot in these field.