Design Of A Wheel-legged Transformable Mobile Robot With Differential Balance Linkage Mechanism

As an important branch of the robot field,mobile robot has been widely used in military investigation,security rescue,environmental monitoring,homeland security,space exploration and other fields with its good comprehensive performance.It has become an important tool to facilitate human society and expand people’s operation space.Due to the limitation of its movement form,the mobility and obstacle crossing ability of the traditional mobile robot can not be taken into account simultaneously.In order to improve the terrain adaptability of the mobile robot,combined with the mechanism research theory,a wheel-legged transformable mobile robot with differential balance linkage mechanism is proposed.The main research contents and achievements are organized as follows:(1)Type synthesis and optimization design of differential balance linkage mechanism: Motion characteristics of differential balance linkage mechanisms and basic conditions to realize its motion function are summarized,and the desired motion pattern of the mechanism is refined.Combined with the screw theory,the mechanisms are classified and synthesized according to the number and type of public constraints.The performance of the mechanisms are compared and a typical mechanism is selected.Kinematic analysis is carried out and its homogenization characteristic is verified theoretically.The kinematic performance evaluation model of the mechanism is established,and the scale parameters of the mechanism are optimized.(2)Structural parameter design of transformable wheel-leg: Based on the planar linkage mechanism,three schemes of transformable wheel-leg are put forward.After comparing performances of the three schemes,the six bar transformable wheel-leg that composed of six rotating pairs is selected.The motion process of the mechanism is analyzed,the conditions for realizing the wheeled mode and legged mode are discussed.Taking the deformation capacity index of the mechanism as the optimization objective,the scale parameters are optimized.The obstacle crossing ability of the wheel-leg is analyzed.Combined with the application scenario,the specific structural parameters of the wheel-leg are determined.(3)Analysis of motion characteristics of mobile robot: The motion of mobile robot on flat ground is analyzed,and its kinematic models in wheeled mode and legged mode are established.The stability in slope terrain is discussed from the perspective of sliding and tipping,and the maximum climbing angle to maintain static stability is obtained.The obstacle surmounting ability in typical stair steps is simulated and analyzed by using simulation software ADAMS respectively.(4)Physical prototype construction and experimental research: The mechanical structure of the robot is designed according to the theoretical parameters.The overall architecture of the robot control system is projected according to the functional requirements,and the main hardwares of the system are selected.The physical prototype of the robot is built and relevant experimental researches are carried out to verify the effectiveness of the robot function and the feasibility of the scheme.The research results of this thesis are of great significance for enriching the structural form,broadening the theoretical research and expanding the practical application of mobile robot.