Analysis of a Shift Quality Metric for a Dual Clutch Transmission

This paper defines the shifting quality evaluation index in detail for DCT (Dual Clutch Transmission) from the perspective of control. The vehicle model for DCT is built using MATLAB / Simulink tools, including the models of driver, load, controller, engine, clutch, transmission (synchronizer), actuators, and vehicle dynamics model. And then a control quality evaluation system is designed. The AHP (Analytic Hierarchy Process) is used to determine weights of the control quality evaluation index and the shifting quality control objectives through the co-simulation of vehicle system model and evaluation system, namely expected control range of each evaluation index, which provides reference and guidance for shifting control strategy and control algorithm of DCT. During the process of shifting control, we apply the strategy of fuzzy control and select the highest shifting quality rating scale as the objective function to optimize clutch engagement speed and engine throttle which influences the shifting quality. Then the optimal solution of fuzzy control rules is obtained. Based on the model of vehicle and the simulation platform of evaluation system about DCT, the simulation result about shifting quality before and after the optimization is observed. Simulation results show that the shifting quality of the vehicle is significantly improved after the optimization of shifting fuzzy control rules.