The Control System Design Of Electrically Power-assisted Bicycles

The biggest difference between electrically power-assisted bicycles and traditional electric bicycles lies in the different methods of controlling the motor,the control way of electric bicycles is an open-loop control,which regulates the speed mainly depends on the feeling of the riders,apparently,the speed will have a certain delay,it's the delay that becomes to the main cause of the frequent accidents of electric bicycles.Corresponding,the way of electrically power-assisted bicycles consists of manpower and electric power,which controls the output of the motor by detecting the size of human power output,in return,the assistance of the motor's output will affect the output of the manpower,consequently,which forms the closed-loop control.Therefore,the security of electrically power-assisted bicycles is far superior to the traditional electric bicycles.At present,the study hotspot of electrically power-assisted bicycles is primarily concentrated in the research of torque sensors,while few people are interested in the study of the riding control algorithm,which really concerns the user's riding feel,now the control Algorithms available on the market are mostly simple proportional control,that is to say,the auxiliary motor will provide assistance in accordance with a certain proportion according to the power of the human.In this paper,our own control riding algorithm of electrically power-assisted bicycles for the sake of achieving a better riding experience.This paper,based on the analysis of the bicycle riding comfort,we present a standard to evaluate the advantages and disadvantages of the riding algorithm,and design the hardware architecture of the power-assisted bicycle.And discuss the riding control algorithm based on the torque sensor technology,which involves the selection of power-assisted mode,the control of special state,stationary control algorithm and slope control algorithm,and the control schemes of these sub-modules are analyzed in detail,at last,the control effect of the algorithm is validated through the field riding.Go a step further,the backup control algorithm of the system without a torque sensor or the torque sensor is damaged is studied in this paper,through the dynamic analysis of the electrically power-assisted bicycle system,the dynamic control model of it is established,and propose the torque estimation algorithm in the riding condition,also,discusses the two backup control algorithms of "speed following algorithm" and "manpower estimation algorithm",and validates the performances of both through experiment data.Ultimately,the manpower estimation algorithm is selected to be used for the design the system control algorithm.Though the verification of abundant experiments that the riding control algorithm designed in this paper can not only provide the excellent experience of daily cycling control,but also can provide a spare control algorithm when the torque sensor is damaged,undoubtedly,which is more considerable.