With the development of electrification, automation, and interconnection of the automobile industry, the demand for vehicular computing has entered an explosive growth era. Massive low time-constrained and computation-intensive vehicular computing operations bring new challenges to vehicles, such as excessive computing power and energy consumption. Computation offloading technology provides a sustainable and low-cost solution to these problems. In this article, we study an adaptive wireless resource allocation strategy of computation offloading service under a three-layered vehicular edge cloud computing framework. We model the computation offloading process at the minimum assignable wireless resource block level, which can better adapt to vehicular computation offloading scenarios and can also rapidly evolve to the 5G network. Subsequently, we propose a method to measure the cost-effectiveness of allocated resources and energy savings, named value density function. Interestingly, with respect to the amount of allocation resource, it can obtain the maximum value density when offloading energy consumption equals to half of local energy consumption. Finally, we propose a low-complexity heuristic resource allocation algorithm based on this novel theoretical discovery. Numerical results corroborate that our designed algorithm can gain above 80% execution time conservation and 62% conservation on energy consumption, and it exhibits fast convergence and superior performance compared to benchmark solutions.

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To prevent irreversible demagnetization of a permanent magnet (PM) for interior permanent magnet synchronous motors (IPMSMs) by flux-weakening control, a robust PM flux-linkage nonsingular fast terminal-sliding-mode observer (NFTSMO) is proposed to detect demagnetization faults. First, the IPMSM mathematical model of demagnetization is presented. Second, the construction of the NFTSMO to estimate PM demagnetization faults in IPMSM is described, and a proof of observer stability is given. The fault decision criteria and fault-processing method are also presented. Finally, the proposed scheme was simulated using MATLAB/Simulink and implemented on the RT-LAB platform. A number of robustness tests have been carried out. The scheme shows good performance in spite of speed fluctuations, torque ripples and the uncertainties of stator resistance.

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A novel fault diagnosis method and fault tolerant scheme for open-circuit faults on traction rectifier are proposed in this paper. When open-circuit fault occurs in any leg of the rectifier, indication will be generated accurately to identify the faulty leg without utilization of any extra sensors. Furthermore, the faulty rectifier can be reconfigured to maintain its full output rate to prevent traction rectifier breakdown. The fault diagnosis process is neither related to control trigger signal nor the load fluctuation. The involved parameters are the input and output voltage of rectifier, which are the most common parameters in rectifier control. Working under zero voltage and zero current, five additional switch sets are adopted for the fault tolerant control process to reconfigure the topological structure between the traction rectifier and traction transformer, meanwhile original structure of the rectifier is retained. Analysis, design and implementing consideration for both normal and abnormal operating situations of traction rectifier are present in this paper. Experiment is processed to verify the effectiveness of the theoretical analysis.

This paper is concerned with finite-time stabilization (FTS) analysis for a class of uncertain switched positive linear systems with time-varying delays. First, a new definition of finite-time boundedness (FTB) is introduced for switched positive system. This definition can simplify FTS analysis. Taking interval and polytopic uncertainties into account, a robust state feedback controller is built such that the switched positive linear system is finite-time bounded. Finally, an example is employed to illustrate the validities of obtained results.

Trains running on a bridge face more significant safety risks. Based on the Unsteady Reynolds-Averaged Navier–Stokes turbulence model, a three-dimensional Computational Fluid Dynamics computational model of the train–bridge–wind barrier was proposed in this study to measure the transient aerodynamic load of the train. The transient aerodynamic load was input into the wind–train–bridge coupling dynamic system to perform dynamic analysis of running safety. Significant fluctuations in the aerodynamic coefficients were found when the train entered and exited the wind barrier due to the dramatic change in flow pattern. The maximum value of the derailment coefficient decreased with the height of wind barriers, which hardly affected the wheel load reduction rate. The 2 m high wind barrier had no evident influence on the running posture of a general high-speed train, while the 4 m high wind barrier was proven to have better protection. Over-protection was found with an even higher wind barrier.

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