Prototype Design And Balance Control Of A Dual-drive Unmanned Bicycle

Electric bicycles are inexpensive,lightweight and convenient,making them the best tool of for the last step in the distribution industry.Unmanned driving can improve delivery efficiency,reduce labor costs and reduce traffic accidents.Unmanned bicycles provide an ideal solution for distribution services.Balancing is an integral part of unmanned bicycle control.Bicycles have features such as underdrive and non-linearity,so their dynamic characteristics are complicated.The control input of ordinary unmanned bicycles is limited,making its balancing control difficult and its motion mode limited.This paper proposed a dual-drive unmanned bicycle to overcome the shortcomings of ordinary bicycles,such as few control inputs and limited motion modes,and performed dynamic modeling and analysis,prototype design and construction,and balance control algorithm design based on it.The unmanned bicycle consists of a frame structure,a counterweight structure,and two steering structures.The bicycle is symmetrical about the frame.It has 5 degrees of freedom and 4 independent control inputs.Each wheel can be used as the driving wheel.Dynamics modeling was performed to the unmanned bicycle.A static dynamic model was established by the momentum moment theorem method controlled by the counterweight structure.The zero-input response and the maximum controllable tilt angle of the bicycle were analyzed.A moving dynamic model was established by the Lagrangian method controlled by the counterweight and steering structures.The controllability of the bicycle was proved.Based on the dynamic models,single-input balance controllers were designed and simulated for different control inputs.The effect of balance control in the case of multiple inputs was also discussed.Under the condition of single control input,a linear quadratic optimal controller was designed for the counterweight input which realized the balance of the bicycle tilt angle within 1° when the unmanned bicycle is stationary;linear quadratic optimal control and fuzzy control were adopted for the steering input which can achieve a balance within 10° in a uniform speed.They also had a certain balance effect on the simultaneous movement of the dual steering structure.Under the condition of multiple control inputs,linear quadratic optimal control was used for both counterweight and steering inputs.Compared with the single control input,the system overshoot was reduced.Finally,a balance control experiment was performed on the physical prototype of the dualdrive unmanned bicycle.The experimental results indicated the effectiveness of the steering controller during a short time.It could help achieve the balance control and cooperative movement of unmanned bicycles completely.