A Motion Study Of The Omnidirectional Mobile Robot

The omnidirectional mobile robot with the MY3 wheels in series is developed based on the narrow working space and the ground inequality,and the omnidirectional motion characteristics of the robot are studied.According to the structure of the wheels,the characteristics of wheels grounding are analyzed,and a continuous model is established based on the analysis results.And the model is validated by simulation.On the basis of continuous modeling,the driving interference condition of MY3 wheel was studied,and it was avoided by designing of motion trajectory to improve the motion accuracy.Firstly,the omnidirectional mobile robot with the MY3 wheels is presented,including the development of the MY wheels and the design of the platform construction of mobile robots.The omnidirectional motion characteristics of the robot are analyzed,and the kinematics and dynamics are established according to the constraint relations.Meanwhile,the change of the grounded radius of the robot and the wheel transition of the robot are studied during the moving process.Secondly,based on the discontinuity of the grounding radius during the movement,a fitting method of sine curve and polynomial curve is presented,which is used to establish the continuous model of kinematics and dynamics.Based on the continuous model,the circular trajectory simulation was carried out,and the position and velocity of the robot were analyzed by using different curve fitting methods.And the advantages of the two curve fitting methods are preliminarily determined by simulation.In order to further determining the optimal curve fitting method,the maximum rolling friction force of the robot is studied,and the relationship between the maximum angular acceleration and the curve parameters during the movement of the robot are analyzed to get the optimal curve parameter.Finally,the driving interference problem of the robot is analyzed according to the unique structure of the series MY3 wheels,and the dangerous driving interference interval of the instantaneous center of velocity is established.In order to optimize the trajectory of the robot,the relationship between different influence factors and trajectory planning are analyzed from two aspects,one is the relationship between the radius of the path and the error of the motion,and the other is the relationship between the cycle of the track and the rotation cycle of the robot.Aiming at the problem of wheel-drive interference,a method of translating and rotating is proposed to realize the reasonable avoidance of force interference to achieve the goal of improving the motion precision of the robot,and the correctness of the trajectory planning method is verified by MATLAB simulation.