Abstract: The shift quality of an automated mechanical transmission is improved and transmission wear is reduced by controlling the armature current of the motor driving the transmission shifting mechanism. The current is monitored by a microcontroller to determine if the shifting mechanism has encountered a snag or has stalled during a shift operation. The microcontroller 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 and thus the sliding clutch and transmission gearing.

Abstract: A control method/system for sensing cold temperature/high viscosity conditions of a transmission lubricant sump (78) in an automated mechanical transmission system (10) without requiring a dedicated temperature sensor and the required CPU input port and input signal processing capacity associated therewith is provided.