International Journal of Vehicle Systems Modelling and Testing (15 papers in press)
Economic optimisation of range-extended electric bus based on AMGA algorithm
by Yunfei Zha, Ronghui Guo, Fangwu Ma, Jinglong Song
Abstract: The power of a range-extended electric bus comes from its battery and range- extender. How to design the range-extender working point for the vehicle in the process of running is the key factor to achieve energy conservation and emission reduction. To solve this problem, a vehicle model was built by using AVL Cruise simulation software. Through Cruise and Isight co-simulation optimisation, a multi-objective optimisation model for per 100-km fuel consumption and pollutant emission is established. Optimal variables include upper and lower limits of the power unit and working point of the range-extender. Adaptive mutation genetic algorithm (AMGA) was used as an optimisation algorithm. Results showed that fuel consumption and pollutant emissions were effectively reduced. The per 100-km fuel consumption decreased by 48.0%, carbon monoxide emission decreased by 49.6%, hydrocarbon emission decreased by 47.28%, and nitrogen oxide emission decreased by 51.1%. The economics of range-extended electric bus have been greatly improved.
Keywords: range-extended electric bus; multi-objective optimisation; AMGA algorithm; optimal working point of range-extender.
Study on the laminated frame strength of heavy-duty fracturing pump truck considering slip effect
by Zhongyan Liu, Wensheng Xiao, Junguo Cui, Xiaodong Sun
Abstract: A differential equation for the slip effect of a continuous superposition beam under asymmetric loads and flexible support is formulated to study the effects of the stress distribution law and the slip effect of laminated frame under actual loads on the overall stress level of the frame. While considering continuity and free boundary conditions, a semi-analytical solution to the slippage of the superposed beam interface is proposed. An experiment for frame strength is designed based on the results of the numerical analysis. A field stress test is performed on the main frame and sub-frame, and the results demonstrate that the slip effect could influence the overall mechanical properties of the laminated frame to some extent. Considering the slip effect conforms to the actual mechanical properties of the laminated frame.
Keywords: fracturing pump truck; laminated frame; stress test; slip effect.
Study on equivalent circuit model of lithium titanate battery for rail transit
by Qiuting Wang, Wei Qi
Abstract: Recently, lithium titanate batteries have been widely used in the energy storage system, because of their attractive performance and environmentally friendly characteristics. Regarding the state estimation of lithium titanate batteries used in the new energy rail transit vehicles, the research work accomplished in our study mainly includes model-driven state estimation method on short time scale, and ageing mechanisms analysis based on state estimation result over a long time scale. The experiments were conducted under constant current and UDDS dynamic conditions using three types of lithium titanate battery. The results indicate that the maximum voltage error of our new battery model and estimation method is less than 2%.
Keywords: lithium titanate battery; equivalent circuit model; first-order RC model; OCV-SOC; Butler-Volmer equation; UDDS.
Prediction and validation of terramechanics models for estimation of tyre rolling resistance coefficient
by Fatemeh Gheshlaghi, Zeinab El-Sayegh, Mirwais Sharifi, Moustafa El-Gindy
Abstract: This research focuses on prediction of the rolling resistance coefficient of an agriculture tyre using Finite Element Analysis (FEA) technique, Bekker, and Wismer-Luth models. The tyre-soil interaction is modelled using FEA and Smoothed-Particle Hydrodynamics (SPH) techniques in Visual Environment's Pam-crash software and validated based on experimental results. A single-wheel tester along with a controlled soil bin at Urmia University, Iran, is used to investigate the effect of a tyre's multi-pass and vertical load on the rolling resistance coefficient of an off-road tyre. In order to calculate the rolling resistance in the Bekker model, a Bevameter device is installed on a carriage moving on clayey-loam soil and a digital penetrometer is used for obtaining the output of Wismer-Luth model. Analysis of experimental data shows that the rolling resistance coefficient increases as the vertical load increases and decreases with each pass of the tyre. These results are used to compare and evaluate the above-mentioned methods. The results of this study will be used to further research on the interaction between a tyre and soil.
Keywords: rolling resistance coefficient; finite element analysis; smoothed-particle hydrodynamics; Bekker; Wismer-Luth; off-road tyre.
Development of vehicle test system and vehicle state estimation based on GPS/INS integrated navigation system
by Jing Gan, Xiaobin Fan, Zeng Song, Mingyue Zhang, Bin Zhao
Abstract: According to the characteristics of a vehicle with a hub motor, LabVIEW vehicle test system was developed based on GPS/INS integrated navigation system. Based on the dynamics of the vehicle system, the estimation of the centre-of-mass lateral deviation was designed. Firstly, the universal data acquisition card and the LabVIEW software were used to build the testing system of an electric vehicle with a hub motor. The data parameters of GPS/INS integrated navigation system were collected and stored in real time. Secondly, the dynamic simulation method was used to build a vehicle model with seven degrees of freedom to estimate the driving state parameters. Finally, the experimental data and simulation results were contrasted to analyse the accuracy of the simulation experiment. The experimental results show that the test bed system worked effectively and its ability of data collection and analysis has been effectively improved. The estimation of vehicle state parameter is accurate, which lays a good foundation for the research on electric vehicles with hub motor in future.
Keywords: LabVIEW; testing system on vehicle; dynamics of vehicle system; vehicle test on road; estimation of centroid sideslip angle; Kalman filtering; vehicle model with seven degrees of freedom; integrated GPS/INS navigation system; estimation of state parameter; vehicle with hub motor.
Interacting multiple model state observer-based coordination control of electro-hydraulic composite electronic stability program
by Houzhong Zhang, Jiasheng Liang, Haobin Jiang, Xing Xu
Abstract: In this paper, an electrohydraulic electronic stability program composite control method is proposed for an electric wheeled vehicle based on an interacting multiple model state observer. A hydraulic system model, an electric-driving wheel model, 2-degrees-of-freedom vehicle reference model and 7-degrees-of-freedom vehicle model are established at the beginning. The necessary state estimations and calculations are also accomplished using interacting multiple model unscented Kalman filter. Then, the proposed upper controller calculates the additional yaw moment by fuzzy sliding mode control, and the lower controller distributes the longitudinal force and additional yaw moment based on the quadratic programming optimisation allocation to improve the vehicle handling stability. Finally, CarSim is used to set the parameters of electric wheeled vehicle model, and MATLAB/Simulink is used to build the control strategies and models, so as to establish the joint simulation platform. The simulation results show that the state observer can estimate the driving state parameters accurately enough under various conditions, and coordination control method mentioned in this paper can significantly improve the electric wheeled vehicles handling stability under extreme conditions.
Keywords: electric wheeled vehicle; electro-hydraulic ESP; composite control method; fuzzy sliding mode control; vehicle handling stability.
Comparing the calibration methods for intelligent driver model using Beijing data
by Md. Mijanoor Rahman, Mohd. Tahir Ismail, Majid Khan Majahar Ali
Abstract: Safe and comfortable journeys in the traffic systems greatly depend on the drivers behaviour. The Car Following Model (CFM) describes the drivers behaviour by following the path of the preceding driver in a traffic flow. The Intelligent Driver Model (IDM) is the most popular CFM for safe and comfortable journeys. This research compares the calibrated methods with each other for Beijing data by using Genetic Algorithm (GA), Sequential Quadratic Programming (SQP) and Simultaneous Perturbation Stochastic Approximation (SPSA). Findings reveal that the IDM simulation parameters, such as maximum acceleration, maximum deceleration, desired speed, minimum headway and minimum jam distance, differ from the IDM calibration parameters by -66.21%, -36.57%, -44.98%, -98.77%, and -9.76%, respectively, for SPSA. Findings also show that the negative percentage values represent the decrease from the IDM simulation parameters, and the positive percentage values represent the increase from the same parameters. The comparison results show that the IDM calibration parameters are more precise with SPSA than GA and SQP for safe and comfortable journeys.
Keywords: car-following; calibration; vehicle dynamics; intelligent driver model.
Improvement of vehicle stability using a controller based on reinforcement learning
by Thiago Antonio Fiorentin, Janaína Ribas De Amaral, Harald Göllinger
Abstract: This paper presents a study on the use of reinforcement learning to control the torque vectoring of a small electric race car in order to improve vehicle handling and vehicle stability. The reinforcement learning algorithm used is Neural Fitted Q Iteration, and the sampling of experiences is based on simulations of the vehicle behaviour using the software CarMaker. The cost function is based on the position of the states on the phase-plane of sideslip angle and sideslip angular velocity. To investigate the maximum ratio of torque distribution that should be set to guarantee stability as well as to investigate the effectiveness of the controller inputs in the learning process, two experiments were done (A and B) with different states and different possibilities of torque distribution. The resulting controller A is able to improve the vehicle handling and stability with a significant reduction in vehicle sideslip angle. The results for this controller also showed that 70% of torque distribution is enough to keep the vehicle stable, and that in this case, it is better to use the absolute velocity instead of its components.
Keywords: reinforcement learning; vehicle dynamics.
Estimating road profiles in quarter car model using two methods
by Ming Min Gong, Dong Cherng Lin, Chang Der Lee
Abstract: Vehicle controllability analysis on real roads can be obtained only if a valid road profile and the tyre road friction model are known. This work determines the time-varying road profiles, called inputs, in a nonlinear system using two input estimation methods. Both algorithms use the Extended Kalman Filter (EKF) with two different recursive estimators to determine inputs and states. Based on the two regression equations, a recursive least-squares estimator with a tunable fading factor is called a conventional input estimation (CIE) with an adaptive weighting fading factor called an adaptive weighting input estimation (AWIE). Numerical simulations of a nonlinear system, quarter-car model, demonstrate the accuracy of the proposed methods. Simulation results show that proposed methods accurately estimate road profiles, tyre forces, and states, and the AWIE approach has better robust estimation capability than the CIE method in the nonlinear system. The simulation results are the same with a single degree of freedom.
Keywords: input estimation; extended Kalman filter; recursive least-squares estimator.
Random sampling and probabilistic consensus for identifying outliers in road surface datasets
by Savio Pereira, John Ferris
Abstract: Road surface measurement plays a crucial role in the modelling and simulation of vehicles and tyres as the road surface is one of the primary means of excitation. A prevalent technique for measuring road surfaces uses scanning lasers whose measurements produce a non-uniform, three-dimensional point cloud representation of the road surface, in which statistical outliers typically manifest. In this work, a novel, axiomatic, probabilistic method for simultaneously identifying outliers and estimating the road surface height at uniformly spaced grid nodes is developed. The method expands on the concepts used in the seminal model-fitting algorithm, Random Sampling and Consensus (RANSAC), to address a situation common in road surface data in which multiple underlying models may exist in a neighborhood of the data. Specifically, the probability that points are valid (inliers) is estimated by the number of valid surface models in which it is a member and, in turn, the probability that a model is valid is estimated by the valid points it has as members. Logistic functions are employed as admissible surrogates when determining the validity of points and surface models during the classification process. The proposed method, called Random Sampling and Probabilistic Consensus (RSPC), is evaluated on a two-dimensional simulated road surface dataset containing 60% outliers in order to demonstrate its effectiveness at identifying outliers and simultaneously estimating grid node heights.
Keywords: RANSAC; logistic function.
Prediction of energy dissipation of off-road vehicles using smoothed-particle hydrodynamics techniques
by Fatemeh Gheshlaghi, Aref Mardani, Zeinab El-Sayegh
Abstract: This paper studies the energy dissipated during experimental and simulated procedures for the pressure-sinkage and shear-strength test. These tests are performed using a clayey-loam soil and modelled as Smoothed-Particle Hydrodynamics (SPH) technique in Visual Environments Pam-Crash software. The hydrodynamic elastic plastic material is used to define the equation of state for the clayey-loam soil. The soil is modelled at five different levels of compaction to represent multi-pass of a tyre over soil. The soil calibration is performed using the pressure-sinkage and direct shear-strength test and validated using experimental data from a soil bin facility. The energy dissipation is calculated using the soil sinkage values at every pass of the wheel. Finally, the results of experimental and simulation dissipation energy are discussed, and the effect of the tyre multi-pass on dissipated energy is investigated and presented. This research will further continue to model an agricultural FEA tyre over clayey-loam soil to compute tyre performance and interaction characteristics.
Keywords: energy dissipation; pressure-sinkage; Bevameter; direct shear-strength; multi-pass; smoothed-particle hydrodynamics.
Research on brushless DC hub motor control system
by Zeng Song, Xiaobin Fan, Jing Gan
Abstract: The brushless DC hub motor is an important part of the wheeled electric vehicle. It has the advantages of simple structure, reliable operation, high efficiency and good speed regulation performance. Based on the mathematical model of brushless DC motor (BLDCM), the ontology model of the brushless DC motor is established based on Matlab2016/Simulink environment combined with S-function. Then the model of speed-current double closed-loop PID, fuzzy adaptive PID and sliding mode control system of brushless DC hub motor is established, and the control system of brushless DC motor is simulated according to the demand of the electric vehicle. The results show that the sliding mode control system has a good control effect and lays a solid foundation for the design of the actual control system.
Keywords: PID control; fuzzy adaptive PID; sliding mode control; brushless DC motor control system; simulation.
A study on the enhancement of amplitude of DCT measured load spectrum considering time-frequency domain damage characteristics
by Li-kui Zeng
Abstract: The indoor enhancement simulation bench test of transmission is an important method of assessment, evaluation and promotion of its performance, Firstly, the actual road load spectrum of automobile transmission is collected on an automobile proving ground using wireless telemetry technology, and the actual load spectrum is pretreated divided gear position. Then, the fatigue damage of load spectrum is analysed based on nominal
Keywords: DCT; enhancement of amplitude; road simulation; time domain damage; frequency domain damage.
Research on the mode switching control of vehicle electromagnetic suspension employing Linear motor
by Xiangpeng Meng, Ruochen Wang, Renkai Ding, Long Chen
Abstract: An electromagnetic suspension employing linear motor is able to harvest the energy otherwise wasted in the suspension vibration while the vehicle is running on rough roads. A switch method of operation modes is put forward to coordinate the contradiction between energy regeneration and vibration isolation. A dynamic model is created to analyse the general properties of energy regeneration suspension under different working modes. Both simulation and experiments are conducted to verify the modelling and advantages. In energy regenerative mode, the dynamic properties of electromagnetic suspension are coincident with those of passive suspension, besides more than 14 W of electricity is harvested while driving at 20 m s-1 on level C road. In active control mode, the RMS of vehicle body vertical acceleration and tyre dynamic load are decreased by 21.35% and 4.24%, respectively, much better than passive suspension, which proves that the mode switching method is simple and effective.
Keywords: electromagnetic suspension; linear motor; mode switching; vibration energy regenerative mode; ride comfort.
Development of a rolling truck tyre model using an automatic model regeneration algorithm
by Shahram Shokouhfar, Subhash Rakheja, Moustafa El-Gindy
Abstract: A three-dimensional finite element model of a rolling radial-ply truck tyre is developed to predict its vertical and cornering properties at relatively high speeds. The model includes a detailed representation of the tyre complex geometry and multi-layered composite structure including the carcass and belt plies, bead fillers and tread. LS-DYNA, a nonlinear finite element code, is used as the simulation tool. An algorithm is developed for efficient formulation of the model for parametric analyses. The validity of the proposed tyre model is demonstrated by comparing the predicted load-deflection, cornering and free vertical vibration characteristics with the reported experimental data. The simulation results revealed robust behaviour of the tyre model up to rolling speeds of 100 km/h. The verified tyre model is subsequently employed to study the influences of various operating parameters, namely, the inflation pressure, vertical load, rolling speed and road friction on the tyre vertical and cornering properties.
Keywords: rolling truck tyre models; multi-layered tyre structure; vertical tyre properties; cornering properties; parametric studies; finite element method; FEM; LS-DYNA; automatic model regeneration; truck tyres; tyre modelling; radial-ply tyres; carcass plies; belt plies; bead fillers; tyre tread; simulation; rolling speed; load deflection; free vertical vibration; tyre inflation pressure; vertical load; road friction; radial tyres.