Research On Structure Design And Motion Control Of Lunar Hexapod Robot

Moon-based equipment is a key technology for achieving lunar exploration missions,which can replace human operations on complex lunar surfaces and complete space related tasks.The soft lunar soil,uneven craters,and weak gravity pose significant challenges to the autonomous cruising and normal operation of lunar based equipment.Therefore,mechanical structure design and precise motion control of lunar based equipment are key to ensuring its completion of lunar exploration tasks.Therefore,this paper designs a hexapod mobile robot suitable for the lunar environment,studies the load capacity of the hexapod robot under low gravity and carries out statics analysis;The kinematics and dynamics analysis of the hexapod lunar exploration robot is carried out,and a "reverse gait" motion mode is proposed to solve the problem of redundant motion of the hexapod robot when it is started,and the simulation verification is carried out;We have designed the control system architecture of the lunar exploration hexapod robot,completed the production of the lunar exploration hexapod robot experimental prototype,and conducted experimental verification in the lunar test module.The main research content of this article is as follows:(1)A mechanical structure of a hexapod robot suitable for lunar terrain environment has been designed.In response to the characteristics of soft and strong adsorption of lunar soil,this paper designs a lunar exploration hexapod robot that combines a hollow leg structure and a cylindrical foot end structure.This design solves the problem of mechanical legs easily sinking during the lunar exploration robot’s walking process;In order to meet the requirements of light weight and high strength for lunar exploration missions,the lunar exploration hexapod robot designed in this article uses Si Cp/Al composite material with low density,good heat resistance,and strong atmospheric corrosion resistance.The overall design and load capacity of the lunar exploration hexapod robot were verified using finite element analysis software ANSYS.The results indicate that using Si Cp/Al composite material as the main material for the production of the lunar exploration hexapod robot can meet the requirements of lunar exploration missions for lunar based equipment.(2)The kinematics and dynamics analysis of the hexapod lunar exploration robot was carried out.In this paper,the D-H method is used to model and analyze the forward kinematics of the lunar hexapod robot,and the geometric method is used to explore the inverse kinematics of the robot;Considering that the gravitational acceleration on the lunar surface is one-sixth of that on the Earth’s surface,the Lagrange equilibrium method was used to analyze the dynamics of the mechanical leg of the lunar exploration hexapod robot and establish the dynamic equation.This research content lays a theoretical foundation for the gait planning of the lunar exploration hexapod robot.(3)ADAMS simulation analysis of the walking mechanism of the lunar exploration hexapod robot was conducted.The dynamic simulation analysis of the walking mechanism of the lunar exploration hexapod robot was conducted using ADAMS simulation software.In response to the starting process of the lunar exploration hexapod robot,this paper proposes a "reverse gait" motion mode,which solves the problem of redundant actions in the starting state of the hexapod robot and realizes the simulation of the motion state of the lunar exploration hexapod robot in a straight walking state.The research content analyzed the change of the center of mass,the angular velocity of each joint of the mechanical leg,the angular acceleration and the torque of each joint during the movement of the lunar hexapod robot,and verified the stability and rationality of the overall structure of the lunar hexapod robot designed in this paper.(4)Designed and built the control system architecture and prototype of the lunar exploration hexapod robot.This article designs and selects hardware for each module of the lunar exploration hexapod robot,selects STM32 as the main control chip,and draws the hardware circuit diagram of the lunar exploration hexapod robot.In addition,the walking gait of the lunar exploration hexapod robot was analyzed.On the one hand,the Ubuntu 18.04 ROS operating system was built in the VMware Workstation Pro environment and virtual simulation experiments were conducted;On the other hand,on-site testing was conducted on the experimental prototype,and the test results proved the rationality and feasibility of the gait planning of the lunar exploration hexapod robot studied in this paper.