Trajectory Planning And Balancing Characteristics Analysis Of A Fully Autonomous Mobile Two-wheeled Balancing Vehicle

As a kind of dynamically stable wheeled mobile robot,fully autonomous mobile dual-wheel balancing vehicle has become a hotspot in robot research in recent years.Compared with the traditional static wheeled mobile robot,its mechanical body is usually designed with high center of gravity and small footprint.Due to the principle of inverted pendulum,the fully autonomous mobile dual-wheel balancing vehicle needs to constantly consume energy to maintain its balance.Stability is the primary performance that a fully autonomous mobile dual-wheeled balancing vehicle must possess,which is not only reflected in simple movements such as forward/backward motion,but also more important in complex movements such as steering.This is because the fully autonomous moving dual-wheel balancing vehicle controls its motion through the cooperation of dual coaxial motors.Based on the structure of the fully autonomous mobile dual-wheel balancing vehicle,this paper analyzes its dynamics and kinematics characteristics,and innovatively uses the trajectory planning method to improve the stability of the fully autonomous mobile dual-wheel balancing vehicle in the steering process,so that it can move along the established trajectory curve at a fast and constant speed without collision.The main research content of this topic is divided into the following four parts:1.The dynamic and kinematics mathematical models of the fully autonomous dual-wheel balancing vehicle were established.Based on the dynamic model,the balance characteristics of the vehicle were analyzed.The kinematics model was used to analyze the relationship between curvature and velocity under the condition of critical tilt in the steering process,and the maximum curvature value of the trajectory was determined.2.According to the discontinuity of trajectory generated by A*path search algorithm,A cubic b-spline curve trajectory planning method based on A*algorithm is proposed.On the basis of the collision free path generated by the original A*path search algorithm,the smooth path of the cubic b-spline curve is utilized to make the trajectory curve have C2 continuity,so as to avoid the continuous start,stop and in-situ steering of the fully autonomous moving dual-wheel balancing vehicle at the path point.3.Considering that the generated trajectory curve may collide with obstacles,and that the curvature does not necessarily meet the requirements of the trajectory curvature of fully autonomous moving dual-wheel balance vehicle,a curve curvature control method based on control point correction is proposed.Firstly,collision analysis is carried out on the trajectory curve.Then,combining with the A*path search algorithm and the properties of the cubic b-spline curve,the moving position of control points is determined,and finally the curvature of the trajectory curve is controlled.4.The feasibility of moving control points to control the curvature of trajectory curve is verified.According to the above analysis process,the algorithm is compiled and simulated on matlab software.Simulation results show that this method can effectively control the curvature of trajectory curve and make it meet the maximum curvature requirement of fully autonomous moving dual-wheel balancing vehicle.