Adaptive window lift control with pinch force based on object rigidity

Abstract

A power window system employs a computer based control that receives signals from a window position sensor. As the window moves, the position sensor produces periodic signals as an output. The computer cyclically looks for a change in the frequency of the signals as an indication that the window is obstructed and decelerating. Based on the instantaneous deceleration, the computer recalls a stored value for motor force. The recalled forces are accumulated in synchronism with the position sensor output during the deceleration, manifesting the force applied to the obstruction as the window presses on it. The window is reversed when the accumulated force exceeds a stored value. The uppermost window position is a stored value for the position sensor output obtained when the window is closed for the first time. Each time the window is closed thereafter, an offset is added to that value, the sum defining the point at which the window engages the window seal. The offset is the change in the position sensor output signal as the window is slowed by the seal until the motor stops when a stored value of force is applied to the seal.