Improved Robust Speed Tracking Controller Design for an Integrated Motor-Transmission Powertrain System Over Controller Area Network

Integrated motor-transmission (IMT) systems have the properties of simple structure, but higher energy efficiency and better drivability. In an IMT powertrain system, the performance of speeding tracking is of importance. It is well known that controller area network (CAN) has been a common communication medium to exchange signals between controller and physical apparatus in vehicular systems. The CAN-bus-induced delays due to the limited network capacity are a challenge to the speed tracking control for the IMT systems involving varieties of CAN communication nodes. In this paper, we aim to design a tracking controller for IMT powertrain systems by considering the CAN-bus-induced delays. To achieve the objective, the discrete-time system model of IMT powertrain systems coupled with the influence of CAN-bus-induced delays is analyzed. Then, a new system augmentation method considering the integral of error is applied to the obtained discrete-time system. With the augmentation technique, the tracking controller design is transformed into a state-feedback controller design for the augmented closed-loop system. In addition, the mixed $H_{\infty }$ and linear quadratic regulator ( $\text{LQR}$ ) performance is considered and a design approach for robust mixed $H_{\infty }/\text{LQR}$ controller is proposed. Finally, simulation and comparison results are carried out. Compared with a conventional proportional-integral controller and an $L_2-L_{\infty }$ controller, the superiority and the improvement of proposed controller are displayed.