Research On Control Technology Of Power Assisted Bicycle

Nowadays,with the rapid development of motor-driven technology,control technology and sensor technology in the fields of engineering and technology,a new type of transportation adapted to people's healthy green travel-the power assisted bicycle-comes into being.The power assisted bicycle belongs to the manpower and electricity hybrid drive motor vehicles,that is,the motor auxiliary system will provide assistant electromagnetic torque according to a certain control law based on the riding status perceived by the torque sensor.At present,there are some power assisted bicycles that adopt the proportional control method in the market.That is,the output of the motor auxiliary torque varies with the pedal torque input proportionally.Obviously,this type of control does not take into account the special riding conditions and the impact of external environmental resistance on riding performance.For example,during the ride,the power assisted bicycle suddenly accelerates and decelerates,then a sudden change in the human power will bring about a sudden change in the power output of the motor,which may cause the power assisted bicycle to rush forward and cause potential safety problems.What is more,when riding on the slope or the wind speed is too high,the output torque of the hybrid system may not be able to effectively compensate the environmental resistance moment,thus affecting the normal running of the power assisted bicycle.This paper starts from the actual riding scene,focusing on the research of the power assisted bicycle riding control technology,and mainly completed the following work:Firstly,in order to obtain the pedaling force data,the circuit system of the crankshaft torque sensor is analyzed and designed.According to the data interference in the sensor measurement process,the application of Kalman filter algorithmin the power assisted bicycle torque detection is studied.Besides,the analysis and modeling of sensor measurement process are carried out.The comparison between the measured data and the filtered data shows that the filtering effect of the Kalman filtering algorithm is improved and the accuracy of the pedaling force measurement is improved.Secondly,in order to obtain the resistance in the riding environment,the kinematics model of the power assisted bicycle system is researched.The dynamic equation of the assisted bicycle and the control equation of the motor are analyzed in detail.The environmental resistance estimation model is further established and the specific mathematical expressions are derived.The results of resistance estimation are analyzed from the aspects of parameter estimation and model estimation and the feasibility of the environmental resistance estimation model obtained in this paper is verified.Thirdly,in order to improve riding performance,the paper takes riding comfort and safety as criteria,combines with sensing equipment,environmental resistance estimation model and fuzzy rule base to research and design control technology of the power assisted bicycle.Including: riding mode selection,special status Control technology,slope control technology and motor steady control technology;and the realization of various control technologies are further analysised.Finally,in order to verify the performance of the riding control technology studied in this paper,an experimental platform of the power assisted bicycle is built.Two sets of comparison tests are carried out between the new control technology proposed in this paper and the traditional proportional control scheme,that is,smooth output test and ramp control test.The experimental results show that the control technology of the power assisted bicycle can not only reach the steady boosting effect of the start and acceleration riding on the flat road,but also compensate the environmental resistance effectively and improve riding comfort.