Control-oriented modeling and torque estimations for vehicle driveline with dual-clutch transmission

Over the years, dual-clutch transmission (DCT) has demonstrated its higher efficiency and superior shift performances over other types of transmissions, and has been increasingly used in modern mass-produced vehicles. However, due to the absence of the smoothing effects of torque converters, vehicles with DCT are easily exposed to driveline oscillations that lead to poor driving quality, especially during gear shifts. Therefore, torque transfer through the driveline should be controlled with great care by two clutches and engine to achieve the DCT's outstanding performance. The main obstacle to the accurate torque control is its lack of adequate sensors in production vehicles. Thus, the objectives of this paper are two-fold. First, a control-oriented model with practical concerns is implemented for DCT drivelines, aiming to accurately describe the powertrain oscillations that should be suppressed by the torque control. Secondly, a real-time torque monitoring strategy based on the proposed model is suggested to deal with the absence of torque sensors. The primary task of the torque estimator is to concurrently estimate the torque transmitted through both clutches and drive shaft by using only readily available data from production cars. The developed torque estimator is verified through multiple experiments under various driving conditions.