Method and apparatus for controlling shift force in mechanical automatic transmission

摘要

The shift quality of an automated mechanical transmission (10) is improved and transmission wear is reduced by controlling the armature current of the motor driving the transmission shifting mechanism (22). The current is monitored by a microcontroller (16) to determine if the shifting mechanism has encountered a snag or has stalled during a shift operation. The microcontroller (16) is programmed to control the duty cycle of a pulse width modulated (PWM) voltage signal, applied to the motor, in accordance with an algorithm which provides both proportional and derivative control of the error between the measured current and a target current. The rapid reduction in current spikes through PWM control reduces the force applied to the shifting mechanism (22) and thus the sliding clutch and transmission gearing. IMAGE