| In recent years,with the explosion of artificial intelligence,the development of autonomous driving technology is changing rapidly.The unmanned bicycle is the representative of the vehicle in the field of autonomous driving.It has the characteristics of small size and simple structure,and can also play a certain role on the narrow road surface.As one of the main functions of the unmanned bicycle,load-bearing plays a vital role in its development.The current research on the load of unmanned bicycles is limited by the change of quality,which cannot cover all the changes of the load in the actual use process.This paper takes the unmanned bicycle as the research object.From the perspective of numerical simulation and physical prototype experiment,this paper studies and analyzes the influence of load mass,up and down placement position and forward and backward placement position on the dynamic balance characteristics of the unmanned bicycle.The main research contents are as follows:(1)The nonlinear dynamic model based on Chaplygin equation is selected according to the characteristics of the dynamic model of the unmanned bicycle;According to the linearization method of Jacobian matrix,the existing experimental data of physical prototype were substituted,and the difference approximation method was used to simplify the calculation process to realize the linearization of the dynamic model.(2)The simulation experiment scheme was designed,and the numerical simulation was carried out according to the weight and placement position of the load.The influence law of the load mass and placement position on the balance characteristics of the unmanned bicycle model was obtained: with the increase of the load mass,the absolute overshoot of the frame roll Angle and the handlebar Angle of the unmanned bicycle gradually increased,and the absolute overshoot of the handlebar moment gradually decreased;The absolute value of overshoot decreases with the higher the load position,while the absolute value of overshoot increases with the handlebar corner speed and handlebar moment.When the load placement position is shifted backward,the absolute overshoot values of the frame roll Angle and angular velocity decrease gradually,the absolute overshoot values of the handlebar Angle increase gradually,and the absolute overshoot values of the handlebar torque increase gradually.(3)The experimental scheme of the physical prototype was designed,and the physical prototype experiment was carried out according to the weight and placement position of the load.The influence law of the load mass and placement position on the balance characteristics of the prototype was obtained in the real environment: with the increase of the load mass,the amplitude of the rolling Angle of the frame and the Angle of the handlebar showed a downward trend on the whole,and the amplitude of the handlebar moment showed a decreasing trend;The amplitude of the frame roll Angle decreases with the increase of the load position.The amplitude of the rolling Angle of the frame decreases as the position before and after the load shifts backward,and the amplitude of the handlebar Angle and the output torque of the handlebar increases.This is basically consistent with the results of numerical simulation,which verifies the correctness of the simulation results.In addition,the output current of the front wheel motor and the angular velocity of the front wheel have no obvious change when the load mass and the position are changed.Based on the linearized model of Chaplygin dynamics model,this paper combined with a full-order sliding mode controller and a Linear Quadratic Regulator(LQR)controller,and conducted numerical simulation and physical prototype experiment.The influence of load mass and position on the balance characteristics of the unmanned bicycle is analyzed.The results can provide some reference for the selection of motor type,battery capacity and load optimization configuration of unmanned bicycle. |
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