Search

In this study, a data-driven adaptive iterative learning Kalman consensus filtering (DD-AILKCF) method is designed for high-speed trains to address the parameter identification and speed consistent optimal estimation problem. The nonlinear train dynamics model is transformed into a linear-like state-space model by using the Full Form Dynamic Linearization (FFDL) technique. Meanwhile, four types of sensors are used to obtain different kinds of datasets to implement the multi-sensor system. The method proposed in this paper consists of two steps. First, an adaptive iterative learning Kalman filtering (AILKF) algorithm is proposed to estimate the fast-time varying train parameter in the iteration domain. Then, based on the identified parameter, a distributed multi-source heterogeneous network consensus filtering (MHN-CF) algorithm is proposed for the speed estimation of high-speed trains. The convergence of the proposed algorithm is derived based on the Lyapunov Function. The proposed method is compared with existing methods by numerical simulations, and the results indicate that the proposed method achieves good effectiveness in improving the accuracy of high-speed train speed estimation.

In this paper, a novel model-free adaptive control (MFAC) algorithm based on a dual successive projection (DuSP)-MFAC method is proposed, and it is analyzed using the introduced DuSP method and the symmetrically similar structures of the controller and its parameter estimator of MFAC. Then, the proposed DuSP-MFAC scheme is successfully implemented in an autonomous car “Ruilong” for the lateral tracking control problem via converting the trajectory tracking problem into a stabilization problem by using the proposed preview-deviation-yaw angle. This MFAC-based lateral tracking control method was tested and demonstrated satisfactory performance on real roads in Fengtai, Beijing, China, and through successful participation in the Chinese Smart Car Future Challenge Competition held in 2015 and 2016.

At present, the aeration-assisted cutting-carrying technology is faced with complexities in the drilling of CBM multi-branch horizontal wells. For example, the aerating pressure is hardly maintained, and the borehole instability may happen. In view of these prominent problems, the technology of double casing tubes & a binary cycle system suitable for CBM multi-branch horizontal wells was developed according to the Venturi principle by means of parasitic tube insufflation which is used for well control simulation system. Then, a multiphase flow finite element model was established for the fluid-cutting particle system in this drilling condition. This technology was tested in field. Double-casing tubes cementing is adopted in this technology and a jet generator is installed at the bottom of the inner casing. In the process of drilling, the drilling fluid injected through double intermediate casing annulus is converted by the jet generator into a high-efficiency steering water jet, which, together with the water jet generated by the bit nozzle, increases the fluid returning rate in the inner annulus space. It is indicated from simulation results that the cutting-carrying effect is the best when the included angle between the nozzle of the jet generator and the vertical direction is 30°. Besides, the influential laws of cutting size, primary cycle volume, accessory cycle volume and drilling velocity on hole cleaning are figured out. It is concluded that this technology increases the flow rate of drilling fluid in annulus space, the returning rate of drilling fluid significantly and the cutting-carrying capacity. It is currently one of the effective hole cleaning technologies for CBM multi-branch horizontal wells where fresh water is taken as the drilling fluid.

The feasibility of substituting nickel for cobalt in La-Mg-Ni-based hydrogen storage alloys to reduce material costs and improve electrochemical properties is investigated. The series of alloys with the chemical formula La0.75Mg0.25Ni2.7+xCo0.4-xMn0.1Al0.3 (x = 0-0.4) that reflects the gradual substitution of Ni for Co are prepared by chemical co-precipitation plus reduction method. The detailed synthesis process, structure, morphology, electrochemical performance, and kinetic properties of the resulting alloy electrodes are discussed in terms of the variation in substitution amount of Ni for Co. Results reveal that the hydrogen storage alloy substituted with x = 0.1 exhibits the best overall electrochemical performance among all investigated samples, whereas the complete substitution of Ni for Co has no significant effect on electrochemical performance. Based on these results, a mechanism underlying the effect of substituting Ni for Co on the electrochemical performance of the resulting alloy is discussed in detail and effectively verified by conducting three electrochemical kinetic experiments. Complete substitution of Ni for Co is found to be suitable for reducing material costs and improving the overall electrochemical performances of La-Mg-Ni-based hydrogen storage alloys.

The feasibility of substituting nickel for cobalt in La-Mg-Ni-based hydrogen storage alloys to reduce material costs and improve electrochemical properties is investigated. The series of alloys with the chemical formula La0.75Mg0.25Ni2.7+xCo0.4-xMn0.1Al0.3(x= 0–0.4) that reflects the gradual substitution of Ni for Co are prepared by chemical co-precipitation plus reduction method. The detailed synthesis process, structure, morphology, electrochemical performance, and kinetic properties of the resulting alloy electrodes are discussed in terms of the variation in substitution amount of Ni for Co. Results reveal that the hydrogen storage alloy substituted with x= 0.1 exhibits the best overall electrochemical performance among all investigated samples, whereas the complete substitution of Ni for Co has no significant effect on electrochemical performance. Based on these results, a mechanism underlying the effect of substituting Ni for Co on the electrochemical performance of the resulting alloy is discussed in detail and effectively verified by conducting three electrochemical kinetic experiments. Complete substitution of Ni for Co is found to be suitable for reducing material costs and improving the overall electrochemical performances of La-Mg-Ni-based hydrogen storage alloys.