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Copyright of Journal of National University of Defense Technology / Guofang Keji Daxue Xuebao is the property of NUDT Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With regard to the rear-drive in-wheel motor vehicle, this paper studies the joint estimation method for the vehicle state and road adhesion coefficient. A nonlinear seven degrees of freedom vehicle estimation model and a tire estimation model are established. A vehicle driving state estimator and a road adhesion coefficient estimator based on the generalized high-order cubature Kalman filter (GHCKF) algorithm are designed. The vehicle state estimator combines the vehicle model and the tire model to calculate the vehicle state parameters, provides the state parameters for the road adhesion coefficient estimator, and realizes the real-time estimation of the road adhesion coefficient. The exponential fading memory adaptive algorithm is used to update the measurement noise variance, and we upgrade the GHCKF to the adaptive generalized high-order cubature Kalman filter (AGHCKF), which estimates the vehicle state and road adhesion coefficient. The typical working conditions using the double GHCKF/AGHCKF estimation algorithm were simulated and analyzed. Then, high-and low-speed driving experiments based on typical working conditions were carried out. An integrated navigation system (INS), global positioning system (GPS), and real-time kinematic positioning (RTK) were used to collect the real-time data of the vehicle, and compare them with the estimated values of the joint estimator, to verify the feasibility of the vehicle-state–road-adhesion-coefficient joint estimator. We compared a high-order GHCKF algorithm, high-order improved AGHCKF algorithm, and a cubature Kalman filter (CKF) algorithm, and the simulation and experimental results show that the joint estimator using the CKF, GHCKF, and AGHCKF algorithms can realize the real-time estimation of the vehicle state and the road adhesion coefficient. The AGHCKF algorithm shows the best effectiveness and robustness of the three algorithms. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Accurate energy flow results are the premise of excavator energy-saving control research. Only through an accurate energy flow analysis based on operating data can a practical excavator energy-saving control scheme be proposed. In order to obtain the excavator's accurate energy flow, the excavator components' performance and operating data requirements are obtained, and the experimental schemes are designed to collect it under typical working conditions. The typical working condition load is reconstructed based on wavelet decomposition, harmonic function, and theoretical weighting methods. This paper analyzes the excavator system's energy flow under the typical working condition load. In operation conditions, the output energy of the engine only accounts for 50.21% of the engine's fuel energy, and the actuation and the swing system account for 9.33% and 4%, respectively. In transportation conditions, the output energy of the engine only accounts for 49.80% of the engine's fuel energy, and the torque converter efficiency loss and excavator driving energy account for 15.09% and 17.98%, respectively. The research results show that the energy flow analysis method based on typical working condition load can accurately obtain each excavator component's energy margin, which provides a basis for designing energy-saving schemes and control strategies. [ABSTRACT FROM AUTHOR]

In order to study the flow characteristics and sealing properties of single phase and two-phase cavitation flows under typical working conditions, the numerical simulation of cryogenic floating ring seals with transitions was carried out, and the features of pressure distribution of rotor face, axial and circumferential direction in the seal clearance were compared and analyzed. The effects of inlet pressure, inlet temperature, eccentricity and speed of rotor on leakage rate, flow loss coefficient, seal force and angle of displacement under single phase and two-phase flow conditions were investigated. The results show that under concentric state, the flow fields of single phase flow and two-phase flow are symmetrical. Under eccentric state, the pressure at larger clearances is lower than that at smaller ones in single phase flow, but greater in the vicinity of seal exit when two-phase is applied, resulting in a lower extent of cavitation near the larger clearance. The leakage rate and seal force both increase as rotor speed decreases or inlet pressure and eccentricity increase, and the characteristic values of two-phase flow are lower than those of single phase flow. The leakage rate and seal force both increase as inlet temperature drops in two-phase flow, while the corresponding values of single phase flow are not affected by the change of temperature. The angle of displacement of single phase flow is little affected by the changes of various parameters, indicating the direction of seal force is always in close proximity to the position of minimum clearance. While the fluctuation of the angle of displacement of two-phase flow is relatively large, and it intends to intensify with the increase of inlet temperature. The inlet flow loss coefficient of single phase flow increases slightly as eccentricity decreases or inlet pressure and rotor speed increase, while the inlet flow loss coefficient of two-phase flow is more sensitive to the changes of various parameters. [ABSTRACT FROM AUTHOR]

The three-dimensional geometric model of the driving and driven bevel gear， differential transmission planetary gear and half axle gear of driving axle main reducer is established by using three-dimensional software UG， and the non-interference assembly model is obtained and the creation of virtual prototype model is completed in the dynamic software Adams by which importing into with the common Parasolid graphics interchange format. Based on the Hertz elasticity contact theory， combining with the actual working status of driving axle for a sightseeing car， the dynamics simulation analysis of the starting， straight driving， turning working conditions are achieved by selecting appropriate contact parameters and applying corresponding constraints and loads. Reliable basis for the further research on kinematics and dynamics characteristics of driving axle main reducer and differential transmission gear is provided and technical support to reduce the vibration of the drive axle main reducer and differential transmission and optimize its performance characteristic is provided.