STEUERSYSTEM FÜR EINE ELEKTRISCHE SCHALTEINRICHTUNG

摘要

A control system for an electric shift apparatus for a motor vehicle having an automatic transmission. The apparatus includes a power module adapted to be mounted on the housing of the transmission proximate the transmission mode select shaft and a control module adapted to be mounted in the passenger compartment. The power module includes an electric motor driving a speed reduction unit which in turn drives the transmission mode select shaft. The control module includes a logic module and a plurality of push button members corresponding respectively to the transmission shift positions. An encoder wheel provides a constant coded signal indicating the instantaneous position of the transmission mode select shaft. The logic module compares the present transmission position to the selected shift position and generates a signal to the motor to move the mode select shaft in a direction to achieve the selected shift position and stop the motor assembly when the encoder signal matches the selected shift position. The logic module provides a closed loop control system which, in the situation where the requested new position is only one position away from the present transmission position, moves the mode select shaft at a relatively slow speed and, in the situation where the requested position is more than one position away from the present transmission position, initially moves the mode select shaft at the relatively rapid speed and thereafter, as the mode select shaft reaches a position within one position of the requested position, moves the mode select shaft at the relatively slow speed to ensure accurate positioning of the mode select member without overshoot.