No abstract

The filling pressure control is one of the key technologies of wet clutches. Pressure sensor is a key component to realize the closed-loop control of the filling pressure. However, with the working hours increasing, the pressure sensor is prone to be faulty. To ensure the filling performance of wet clutches, this article investigates a pressure sensor fault diagnosis and fault-tolerant control strategy for the filling phase of wet clutches. First, the dynamic model of a hydraulic clutch control system is established where the clutch pressure sensor fault is considered. Second, the optimal filling pressure reference trajectory is constructed by Pontryagin’s minimum principle. In the fault-free case, a feedback controller is designed to track the desire pressure trajectory with an observer estimating the unmeasurable state of the system. Third, an adaptive observer is constructed to estimate the pressure sensor fault. Based on the estimated sensor fault information, a pressure sensor fault-tolerant control strategy is proposed for the filling phase of wet clutches. Simulation results show that the proposed fault-tolerant controller can realize smooth and precise clutch-filling control with pressure sensor fault.

No abstract

Speed sensors in the dual clutch transmission (DCT) play an essential role in designing the vehicle launching and gear shifting strategy. The speed information can also be used to monitor whether the DCT system operates normally. The vehicle performance will degrade rapidly once the speed sensor occurs fault, which may lead to poor driving experience. With increasing working hours and poor working environment, the speed sensors are prone to failure. In order to monitor the sensor failure, this article proposes a robust speed sensor fault diagnosis algorithm based on an unknown input observer (UIO). First, the dynamic model of a DCT powertrain is constructed which captures the internal and external disturbance in the system. Based on the dynamic model, a sensor fault detection algorithm is presented by designing an UIO. Second, a set of UIOs is developed to identify which sensor occurs fault. Finally, a sensor fault estimation method using the UIO is proposed. Simulation results reveal that the speed sensor faults can be detected, isolated and estimated, which may further be used for fault-tolerant control of a DCT system.