Mechanism Analysis And Research Of Spherical Robot Driven By Double Omni-directional Wheels Fixed Up Orthogonally

Spherical robot is a new mobile robot with spherical shell structure.Compared with other mobile robots,spherical robot can be used in different fields widely because of its unique advantages.At present,the research focus on spherical robot is mainly in the aspects of new drive mechanism design,kinematics and dynamic characteristics analysis,and motion control.In this paper,a new type of drive mechanism design for a spherical robot driven by double omni-directional wheels fixed up orthogonally is proposed,and its mechanical structure and control system are designed in detail,and its motion characteristics are analyzed.Firstly,this paper analyzes the new structure of the spherical robot driven by double omni-directional wheels fixed up orthogonally,constructs the digital three-dimensional model,and completes the kinematics and dynamics analysis of the robot.Based on the theory of kinematics and contact mechanics,the motion model of the spherical robot driven by double omni-directional wheels fixed up orthogonally is constructed in detail.The plane-ball system and the drive unit system are analyzed theoretically,and the movement position and gesture relationship between the driving unit and the sphere is established.Based on the kinetic principle,the dynamic model of the spherical robot driven by double omni-directional wheels fixed up orthogonally is established by using the Newton-Euler method.The dynamic model is numerically solved by the Runge-Kutta method,the curve of the changes of state variables of driving unit and sphere are obtained.Secondly,this paper also makes a comprehensive and detailed analysis of the movement of spherical robot driven by double omni-directional wheels fixed up orthogonally.The linear motion is decomposed into three stages:start-up,acceleration and uniform,and the complexity of analysis is reduced.The mathematical model of uniform motion is constructed by using differential method.The iterative recursive method is used to obtain the velocity variation curve between the sphere and the omnidirectional wheel.And the theoretical characteristics of the steering movement,the climbing movement,the obstacle movement and the jumping motion of the spherical robot are analyzed in detail.Then,using the ADAMS software to simulate the motion of the spherical robot,the theoretical analysis of the spherical robot is verified.Finally,the fabrication of the physical prototype is completed.Based on the principle of PWM speed control,the control system is designed and manufactured.The test of the prototype is carried out,which further supports the theoretical analysis of the spherical robot driven by double omni-directional wheels fixed up orthogonally.The above research work provides a reference for the further study of spherical robots.