Pinch Detection of Power Window Using Disturbance Observer for Obstacles with Wide Range of Force Deflection Ratios

This paper proposes a pinch detection method for an automotive power window. Due to a power window system, we can easily rise and lower a window glass only by pressing a switch. However, if the window is rising while there is a finger or an arm between the window frame and the window glass, it might occur a pinching accident. In order to avoid injuries by the accident, an anti-pinch control that detects the pinching and lowers the window glass, is installed in a power window system. In this paper, an anti-pinch control that can detect pinching of the object with both small and large force deflection ratios is proposed. In order to achieve it, the pinch state index is calculated from the motor angular speed and detects pinching when it exceeds the threshold. The main process of calculating the index is realized by a disturbance observer and a non-linear gain. When an object with small force deflection ratio is pinched, the index moves like a pinch force, and when an object with large force deflection ratio is pinched, the index increases faster than a pinch force by the non-linear gain. Performance and effectiveness of the anti-pinch control is evaluated by the experimental data measured on a power window test rig.