Research On Control Method Of Two-Motor-driven Windscreen Wiper System

Windscreen wiper is a kind of mechanical device which is used to clean thevehicle’s windshield, and now two-motor-driven windscreen wiper system is becomingwiper’s development trend. This kind of wiper system configures an independent motorfor each side of wiper and cancels traditional four-bar linkage, saving vehicle’s interiorspace and reducing mechanical noise. Meanwhile, both sides of wiper system arecontrolled independently and the whole system operates stably and reliably. Aiming atthis kind of windscreen wiper system, its dynamic model, trajectory planning, trackingcontrol and synchronous control are researched. The main content is shown as bellow.First, the structure of two-motor-driven windscreen wiper system is analyzed andthe dynamic torque balance equations are built contraposing motor and wiper arm. Also,the stick-slip vibration between wiper blade and windshield are analyzed, based on theanalysis of wiper’s nonlinear friction characteristic, the mathematical description aboutwiper’s nonlinear friction model is given. And then, the nonlinear mathematical modelof two-motor-driven windscreen wiper system and corresponding simulation model arebuilt. Moreover, open loop simulation tests are done under different control voltagesand different wiper’s angular speeds, verifying the relationship between wiper system’sstrong nonlinear friction characteristic and angular speed. Thereby, it provides basis forcontroller’s design.Secondly, according to the conclusion of wiper’s friction characteristic analysis,the planning method about wiper’s trajectory is proposed. Wiper’s angular speed andangular acceleration are equal to zero at initial position and terminal position to ensurethat wiper reverses smoothly. Also, wiper’s expected angular speed is in high speedzone to avoid stick-slip vibration. Furthermore, in accordance with nonlinearcharacteristic of wiper’s mathematical model, the controller is designed based onbackstepping method to realize wiper’s tracking control. Afterwards, the control effectsof controller parameters are analyzed by simulation tests. At last, on account of nominalfriction characteristic curve, variable friction characteristic curve and smaller angular speed curve, the simulations are executed respectively to verifying effects of trajectoryplanning and tracking control.Finally, in order to realize synchronous control of both sides of windscreen wipersystem, the cross-coupling controller is designed. By the analysis of cross couplingcontrol’s synchronous control principle and contour error, wiper’s contour error modelis built. And then, cross-coupling controller which has variable gain coefficients isdesigned. In the end, cross-coupling controller’s effect is checked when wiper isaffected by disturbance torque, the simulation results shows that the synchronization ofboth sides of wiper system can be achieved by variable gain cross-coupling controller.