Development and Implementation of Hardware in the Loop Simulation for Dual Clutch Transmission Control Units

A control oriented model of a Dual Clutch Transmission was developed for real time Hardware In the Loop (HIL) applications. The model is an innovative attempt to reproduce the fast dynamics of the actuation system maintaining a step size large enough for real time applications. The model comprehends a detailed physical description of hydraulic circuit, clutches, synchronizers and gears, and simplified vehicle and internal combustion engine sub-models; a stable real time simulation is achieved with a simplification of the model without losing physical validity. After an offline validation, the model was implemented in a HIL system and connected to the TCU (Transmission Control Unit) via two input-output boards, and to a load plate which comprehends all the actuators. The paper presents a selection of the several tests that have been performed for the development of the DCT controller: electrical failure tests on sensors and actuators, mechanical failure tests on hydraulic valves, clutches and synchronizers, and application tests comprehending all the main features of the control performed by the TCU, i.e. drive away and gear shift strategies, and interactions with the driver. Furthermore, the paper shows that the model is capable of reproducing the behavior of the real system during adaption procedures performed by the TCU under particular conditions, i.e. synchronizer position detection and clutch pressure characteristic detection. Being based on physical laws, in every condition the model simulates a plausible reaction of the system to the imposed failure or maneuver, as demonstrated by the possibility of performing a complete new software release test in fully automatic mode.