Control-Oriented Models for Real-Time Simulation of Automotive Transmission Systems

Abstract

-A control-oriented model of a Dual Clutch Transmission (DCT) was developed for realtime Hardware In the Loop (HIL) applications, to support model-based development of the DCT controller and to systematically test its performance. The model is an innovative attempt to reproduce the fast dynamics of the actuation system while maintaining a simulation 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 submodels. As the oil circulating in the system has a large bulk modulus, the pressure dynamics are very fast, possibly causing instability in a real-time simulation; the same challenge involves the servo valves dynamics, due to the very small masses of the moving elements. Therefore, the hydraulic circuit model has been modified and simplified without losing physical validity, in order to adapt it to the real-time simulation requirements. The results of offline simulations have been compared to on-board measurements to verify the validity of the developed model, which was then implemented in a HIL system and connected to the Transmission Control Unit (TCU). Several tests have been performed on the HIL simulator, to verify the TCU performance: electrical failure tests on sensors and actuators, hydraulic and mechanical failure tests on hydraulic valves, clutches and synchronizers, and application tests comprehending all the main features of the control actions performed by the TCU. Being based on physical laws, in every condition the model simulates a plausible reaction of the system. A test automation procedure has finally been developed to permit the execution of a pattern of tests without the interaction of the user; perfectly repeatable tests can be performed for nonregression verification, allowing the testing of new software releases in fully automatic mode.Re´sume´-Mode´lisation oriente´e-controˆle pour la simulation en temps re´el des syste`mes de transmission automobile -Un mode`le oriente´vers le controˆle d'une transmission a`double embrayage (DCT, Dual Clutch Transmission) a e´te´de´veloppe´et imple´mente´en temps re´el dans un syste`me Hardware In the Loop (HIL), pour supporter le de´veloppement du controˆleur DCT et pour tester syste´matiquement ses performances. Le mode`le repre´sente une tentative innovatrice de reproduire les dynamiques rapides du syste`me d'actionnement tout en conservant une dimension de pas de calcul assez grande pour l'application en temps re´el. Le mode`le comprend une description physique de´taille´e du circuit hydraulique, des embrayages, des synchroniseurs et des engrenages, et des sous-mode`les simplifie´s du ve´hicule et du moteur ac ombustion interne. Comme l'huile circulant dans le syste`me est caracte´rise´e par un module de compressibilite´e´leve´, les dynamiques de pression sont tre`s rapides, pouvant provoquer une Oil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 70 (2015), No. 1,...

Modeling and Optimal Shift Control of a Planetary Two-Speed Transmission

“…Sorniotti sprag clutch to the traditional MT, although it is difficult to shift seamlessly due to the MTs' layout [17]. Two clutches are used in a DCT for removing the torque interruption during gear-shifting [18,19]. Ruan et al [20] developed three case layouts of powertrain system for EVs, and they found that CVT can reduce energy consumption, and manufacturing cost.…”