Zheng Taixiong

Transportation-cyber-physical-systems-oriented engine cylinder pressure estimation using high gain observer*

In transportation cyber-physical-systems (T-CPS), vehicle-to-vehicle (V2V) communications play an important role in the coordination between individual vehicles as well as between vehicles and the roadside infrastructures, and engine cylinder pressure is significant for engine diagnosis on-line and torque control within the information exchange process under V2V communications. However, the parametric uncertainties caused from measurement noise in T-CPS lead to the dynamic performance deterioration of the engine cylinder pressure estimation. Considering the high accuracy requirement under V2V communications, a high gain observer based on the engine dynamic model is designed to improve the accuracy of pressure estimation. Then, the analyses about convergence, converge speed and stability of the corresponding error model are conducted using the Laplace and Lyapunov method. Finally, results from combination of Simulink with GT-Power based numerical experiments and comparisons demonstrate the effectiveness of the proposed approach with respect to robustness and accuracy.

Development and implementation of the ABS based on model library

In order to solve the shortcomings of expandability and maintainability in the traditional process of ABS development, the ABS model library is put forward and applied in the development of ABS. The hierarchical system structure of the ABS model library is constructed on the theory of ABS. Under powerful visual environment of Simulink, the reusable technology is applied to construct the ABS model library which is based on hierarchical modeling method. All modules of the ABS model library are programmed with C MEX S-Function which has the advantage of easily downloading to hardware. After testing the simulation, the RTW technology is used to automatically generate the control code. Finally, the experiment results show that the simulation effect of ABS model which is based on ABS model library is closed to the actual result of road test.

Engine cylinder pressure estimation based on the robust sliding mode observer

Cylinder pressure is an important parameter for engine combustion analysis and fault diagnosis. In order to improve the estimation precision and the tracking speed of cylinder pressure, the method of engine cylinder pressure estimation based on the robust sliding mode observer is proposed. On the basis of the establishment of the engine dynamic model, it designes the robust sliding mode observer. According of the Lyapunov stability theory, it gets the feedback matrix of the robust sliding mode observer to guarantee the observer convergence, simultaneously, it proposes the robust control strategy to ensure the robustness for the nonlinear uncertain part of the observer. The simulated result show that, compared with the conventional sliding mode observer, the method of engine cylinder pressure estimation based on the robust sliding mode observer not only has higher estimation precision, but also has quicker tracking speed.