Research Of Dual-motor Wiper Controller Control Algorithm

With the continuous development of electronic industry and automobile industry, electronic technology is more and more widely used to equip vehicles in recent years. Traditional mechanical windshield wipers are gradually replaced by windshield wipers system driven by two motors. In two-motor wiper system, the mechanism which was used to connect the two wipers together is completely taken off. As a result, noise and breakdown produced by the mechanism could be evidently reduced, and we could also save the power consumption as well as the space needed for the wiper system. In addition, we can place the wiper system more freely, because the limitation on distance or angle does not exist anymore.For the work method of dual-motor wiper, we need to solve the following two problems:One is how to make the wipers swing according to certain rules; the other is how to avoid the collision of the wipers. So in this paper, we study the control algorithm for the dual-motor windshield wiper system.Firstly, we introduced the basic conception of differential flatness. The theory is the mathematical foundation of system modeling. By system modeling, we can get two desired trajectory of wipers. Besides, we built the stimulant model based on the real dual-motor wiper and found out the flat output of the system according to the principle of differential flatness and Kirchhoff s voltage law. Then, we planned the nominal trajectory of the flat output under the constraints of the wipers’motion and distance limitation. Finally, we got the nominal trajectories of each side’s wiper swing angle and DC motor’s input voltage.Secondly, we studied the trajectory tracking problem of dual-motor windshield wiper system. The interference in real operating condition will trigger the wipers swing angle deviating from nominal trajectories, we should keep the wipers to track the nominal angular position trajectory. So we designed the control scheme with feed forward and feedback for each side system. The feed forward signal was the DC motor’s nominal input voltage and the feedback controller would correct feed forward voltage signal based on deviation signal of the wiper swing angle. We designed an improved incremental digital PI controller as the feedback controller and it could eliminate the integral saturation effectively. The experimental results showed that the above-mentioned control method could make the each side system have a good performance in wiper swing angle trajectory tracking.Finally, we studied the coordinating and synchronizing control problem of dual-motor windshield wiper system. In order to achieve the coordination operation and realize informational interaction between wipers, we needed to design synchronization controller. Firstly, this paper introduced the commonly used method of synchronous motor, the parallel synchronous control system which was suitable for stable and relatively simple system adopted open loop structure and each unit kept running independently, but the system could not guarantee the synchronization of the whole system. Master-slave synchronous control, known as cascade control, of which slaver motor could always subordinate the master motor, but when the slaver’s running status changed due to interference, the master remained running in the same way, leading to the failure of two motors’synchronicity. The method was mainly applied to some industrial automation production situations with low requirements of synchronous accuracy. On the basis of parallel synchronous control, cross coupling synchronous control had information interacted during work. Through the built-in controller, motor could develop self operation parameters calibration, enhancing the synchronization between the motors. But this kind of control mode was only applicable to the two motors’synchronous control, while deviated coupling synchronous control method had obtained the improvement according to the cross coupling synchronization control, this method which was with a better performance of synchronization control could effectively overcome the shortcomings of cross coupling synchronous control. Secondly, we verified the effect of the master-slave synchronous method through simulation experiment and proposed a new system synchronous control method based on clock synchronization controller through analyzing the experimental results. Thirdly, we made an actual working condition of wiper blade by introducing various jamming signal. In the condition, we made experiments about the synchronous controller based on clock synchronization controller. As a result, this method could realize safely synchronous operation of the wipers.