Building Of Hardware Platform And Study Of Control For Dual-motor Windshield Wiper System

With the rapid development of automotive electronic technology, the requirements ofautomobile factories and consumers for automobile electronic equipments are much morethen before. The comfort, convenience, efciency, safety and fashion of vehicle equipmentare paid more attention. The wiper is one of the most common body equipments. It isused to clear water and dirt on the windshield surface and this will ensure that driverscan have a good driving vision. So its performance will directly efect the driver’s trafcsafety.Now, most vehicles are equipped with traditional wiper which is driven by singlemotor. The wiper motor drives the four-bar linkage to realize the cyclical swing in thesame direction of the two wipers. This mechanical structure of this kind wiper is complex,it not only increases the weight of the car, but also takes up a lot of space of enginecompartment. In addition, it has drawbacks of large noise and high failure rate. Becauseof the two wipers swing in the same direction, the area cleaned by the wipers is limited,so there is a blind spot in windshield of the passenger side. The dual-motor wiper whichwe study in this paper is a new kind of wiper equipment, it can solve these problems.The dual-motor wiper contains two independent sets of wiper systems, each of them hasDC motor, reduction gear and wiper. The two motors are placed in lower left and rightcorner of the windshield, to drive the wiper of each side. There is not need of mechanicalstructure to link the two wiper, the two wipers can realize the opposite movement. Itwill make the cleaned area of windshield larger than before and provides a open and clearvision to the driver. The dual-motor wiper has smaller noise, lower failure rate and thestructure is much more compact than the traditional wiper.For the work method of dual-motor wiper we need to solve these two problems oneis how to make the wipers swing according certain rules the other is how to avoid thecollision of the wipers. So in this paper, we study the control algorithm for the dual-motorwindshield wiper system.To ensure the reliability and efectiveness of the controller, we built the hardware platform of the dual-motor wiper system as the accurate plant in the experiment. Thisplatform uses the real dual-motor wiper equipments and we assembled them with thewindshield according the real vehicle. We designed and made the drive circuit which isbased on H-bridge reversible PWM converter to drive the wiper DC motor. To measurethe angle of the wipers as the feedback signal, we also made the angular transducer withthe magnetic field sensor and sensor signal conditioning IC.After completing the platform, we built the mathematical model based on the realdual-motor wiper and found out the flat output of the system according to the principleof diferential flatness. Then, we planned the nominal trajectory of the flat output underthe constraints of the wipers’ motion and distance limitation. Finally, we got the nominaltrajectories of each side’s wiper swing angle and DC motor’s input voltage.The interference in real operating condition will trigger the wipers swing angle deviatefrom nominal trajectories, we should keep the wipers to track the nominal angular positiontrajectory. So we designed the control scheme with feed forward and feedback for eachside system. The feed forward signal is the DC motor’s nominal input voltage and thefeedback controller will correct feed forward voltage signal based on deviation signal ofthe wiper swing angle. We designed an improved incremental digital PI controller asthe feedback controller and it can eliminate the integral saturation efectively. We alsostudied the application of PID neural networks in dual-motor wiper and found that theneural networks and the control law can be combined together efectively. The PID neuralnetworks feedback controller has the ability of adaptive adjustment for the PID parameterswithin a certain range. Compared with traditional neural networks, the selection of theparameters and weights is more efcient. The experimental results show that the above-mentioned control method can make the each side system have a good performance inwiper swing angle trajectory tracking.When the wiper encounters a larger disturbance, there is still a greater deviation ofthe wiper swing angle if the wiper only under control of PID controller and the two wiperswill collide. For avoiding the collision, we should add the synchronous controller to thewiper system besides the PID controller of the each side. The synchronous controller isbased on the theory of adjusting the clock to change the given trajectory of the side whichis under control. It ensures that the wiper of both sides to coordinate the operation. Theexperimental results show that when either wiper closes to the other side’s wiper due tothe interference, the trend will be efectively suppressed within the synchronous controller.