Anti-Trapping Protection: Notes

The SHD has anti-trapping protection for all closing functions. In order to detect trapping, hall sensors are integrated into the motor. The sensors provide direct measurement of the closing speed and end positions. They are also used for calculation of the sunroof closing power. The result of the calculations are stored in the control unit as the "characteristic curve".

For each closing operation, the required closing power is determined. The characteristic curve is then calibrated to this value and as closing proceeds, the currently measured values are compared. If the measured force increases to a value above the characteristic curve by more than the triggering threshold, the sunroof is reversed.

In compliance with governmental regulations, the maximum closing power should not exceed 100 N in the range of 25 mm to 4 mm. The mass inertia of the moving parts makes it necessary to reduce the adjustment speed of the roof in this area. This is done by reduction of the voltage applied to the motor. The voltage is adjusted by pulse width modulation (smooth-rundown feature).