Design Research And Experiment About A Climbing-Rolling Robot For Lunar Extreme Environment

In the lunar exploration mission,some valuable scientific targets exist in the rugged terrain environment that the current lunar detection robot cannot reach,such as lunar caves and craters.At present,the existing conventional robot configuration is not suitable for this kind of complex lunar extreme environment to perform tasks.Therefore,the development of lunar surface robot with more stable and flexible movement and adaptability to extreme environment(such as cave and crater)is the key problem faced by the current lunar surface patrol detection.In view of the scientific detection mission requirements of the lunar extreme environment,combined with the advantages of the leg-enabled robot’s strong adaptability to the unstructured terrain and the rapid movement of the wheel-enabled robot,supported by the NSFC project and the national defense science and Engineering Bureau’s pre research project,this paper proposes a climbing roll robot configuration design which is composed of 4R1 S mechanism,double rocker mechanism and crank rocker mechanism The scheme has the advantages of smart spatial layout,quick switch between climbing and rolling modes,convenient and reliable control,etc.Around the configuration,motion characteristics and gait planning of the climbing roll robot,the research work of robot structure design,kinematics analysis based on D-H modeling method of robotics,and kinematics analysis based on kinematics and dynamics is carried out.The kinematic characteristics of the crawling mode and rolling mode are obtained,the kinematics simulation and prototype test are carried out,and the crawling of the robot is got.It provides a theoretical basis for the follow-up motion control and multi motion mode control.The main contents of this paper are as follows:Firstly,based on the theory of mechanism and bionics,a new configuration scheme of climbing and rolling robot is proposed around the detection environment of lunar surface extreme environment(lunar crater and karst cave).According to the requirements of lunar crater and cave extreme environment,the robot configuration in different application scenarios is studied,and the composition and basic working principle of the configuration scheme are introduced.Secondly,combined with the D-H modeling theory of robotics,the whole kinematics of the robot is studied,and the body coordinate system and the single leg coordinate system are established.The polynomial trajectory planning of the single leg of the robot is established to solve the problem of the discontinuity of the velocity and acceleration of the trajectory of the foot in the process of crawling forward,which lays the foundation for the following trajectory tracking and gait planning analysis of the robot crawling.Thirdly,aiming at the crawling motion mode under the flat road surface,the research on the straight travel,steering and pose adjustment based on kinematics is carried out,the joint angle variation in the corresponding motion process is obtained,and the stability criterion under the crawling mode is established,which provides the theoretical basis for the position control of the crawling motion of the robot.According to the application scenarios of flat land,slope and obstacle crossing in rolling mode,this paper analyzes the parameters that affect the rolling motion performance,gives the calculation method of the motion performance in rolling mode,clarifies the critical conditions of climbing and obstacle crossing in rolling mode,and provides the basis for the selection of the motion parameters in rolling mode.According to the external conditions such as terrain and target task,the switch strategy of crawling and rolling motion mode is established.Finally,respectively to climbing and rolling mode,robot’s motion simulation based on ADAMS is carried out,the motion parameters in the process of straight travel,steering,posture motion between angles of the leg joint with a robot,and the structural parameters of rolling mode and environmental conditions,the influence of the obstacle-surmounting performance relationship for climbing a hill are analyzed,the rolling hills,and under the mode of obstacle surmounting driving force and initial velocity is obtained.In this paper,the moving mode switching method of crawling and rolling robot is proposed.Through the combination of simulation and experiment,the rationality of the structure design and the correctness of the motion analysis model are verified.