Research On Wheel-legged Hybrid Mobile Robot Based On Eccentric Paddle-wheeled Mechanism

As a typical representative of robotics technology,mobile robots can replace humans to perform dangerous tasks in complex and harsh environments such as expeditions and disaster relief,resource exploration,military strikes,and pipeline maintenance.It has extremely high research significance and broad application requirements.In order to solve the problems of traditional single-mode mobile robots such as single mode and insufficient motion performance,improve the robot's obstacle-crossing ability and adaptability in unstructured environments,and meet the motion requirements of different terrains.Based on the research of the three-degree-of-freedom amphibious motion propulsion mechanism e Paddle(Eccentric Paddle Mechanism),this thesis takes the wheel-legged deformation mechanism as the research starting point,and proposes a wheel-legged hybrid mobile robot based on the two-degree-of-freedom eccentric paddle-wheeled mechanism(2-DOF e Paddle).Thanks to the coordinated cooperation of the eccentric wheel and the paddle rod,the robot has two movement modes: wheeled and legged,and three movement gaits: Circular Wheeled Gait(CW)and Passive Paddle Wheeled Gait(PPW)and Active Paddle Legged Gait(APL),which have both the maneuverability of a wheeled robot and the ability to overcome obstacles of a legged robot.The main contents of this paper include:(1)This thesis proposes a two-degree-of-freedom eccentric paddle wheel mechanism(2-DOF e Paddle),which has two coaxial active joints of the wheel and the paddle rod,and is independently driven by two motors,which improves dynamic performance.Furthermore,the basic kinematics model of the eccentric paddle wheel mechanism is deduced,the vector relationship between the wheel joint and the paddle rod joint is obtained,and the model design of 2-DOF e Paddle-based robot is completed.The robot has a simple and compact structure,stable transmission,strong obstacle crossing performance and environmental adaptability.(2)This thesis analyzes the realization methods of the robot's three movement gaits(CW,PPW and APL)and the complete obstacle-climbing action plan.Taking the two-module 2-DOF e Paddle-based robot as an example,the linear and steering kinematics models of the robot under the CW are established.The necessary condition for the successful obstacle-crossing of the robot is put forward: the margin of slippage D?0.Through the static analysis and the moment synthesis method,the obstacle-crossing posture model of the robot under three gaits is derived,and the analytical expression of slip margin is obtained.(3)This thesis first completes the simulation analysis of the obstacle-climbing kinematics models under three motion gaits of the robot,obtains the obstacle-climbing posture sequence of the robot under the PPW,and analyzes the climbing performance of the PPW and APL.Secondly,a control system based on user processing layer,information interaction layer and drive execution layer is proposed.Serial communication is used as the data transmission method between the mobile control platform and the motor drive system,which realizes the independent drive of each degree and reduces the control difficulty.And two types of robotic motion control software are developed based on C# compiled language.Finally,two robotic prototypes with two modules and four modules 2-DOF e Paddle are built.(4)Based on the prototype of the robot built,this paper first completes the linear,steering and obstacle-climbing motion experiments of the two-module 2-DOF e Paddle-based robot.The experimental performance is consistent with the simulation results,which verifies the accuracy and scientificity of the model.Secondly,completed the basic movement experiment of the four-module 2-DOF e Paddle-based robot,the complete single-step step-climbing experiment,the adaptability experiment in the outdoor environment,and the load movement experiment.The results show that the robot has strong obstacle-overcoming performance and environmental adaptability.Finally,based on experimental results,the optimal gait of the robot under different evaluation indicators is discussed.Compared with the3-DOF e Paddle,the 2-DOF e Paddle-based robot has a simpler and more compact structure,a lighter weight,a reduced degree of freedom,and a significant improvement in the ability to overcome obstacles while retaining the wheel-legged compound movement mode.