Search

The hierarchical control strategy was proposed to solve the problem that distributed electric vehicle was easy to lose stability under lane change or extreme conditions with high speed and low adhesion coefficient. The stability of the vehicle was analyzed, and the opening conditions of the controller were judged. In the upper controller, the fuzzy sliding mode control was adopted. The additional yaw moment was obtained by integral sliding mode control. In order to reduce the chattering of integral sliding mode controller, the fuzzy controller was used to optimize. In the lower controller, the longitudinal force distribution types were adopted based on tire load rate and axial load ratio, and the two types of torque distribution were compared. Through Carsim and MATLAB/Simulink co-simulation, the verification tests were carried out on high speed pavement with high adhesion and low speed pavement with low adhesion, respectively. The results show that the proposed stability control strategy can effectively improve the vehicle stability, and both of the two torque distributors have good control effects, while the effect of the longitudinal force distribution based on axle load ratio is better. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jiangsu University (Natural Science Edition) / Jiangsu Daxue Xuebao (Ziran Kexue Ban) is the property of Editorial Department of Journal of Jiangsu University (Natural Science Edition) 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.)

To evaluate the ride comfort of vehicle, the 8-degree-of-freedom dynamic model of the double-motor-driven electric vehicle with front and rear axles was established based on MATLAB/Simulink software with considering the vertical degrees of freedom of four wheels, the vertical movement of driver and seat and the vertical movement of body, the pitching movement, the roll movement. With the excitation input of white noise of grade C pavement, the acceleration speeds of center of mass, roll, pitch and seat of the body were simulated and analyzed respectively. Particle swarm optimization (PSO) was used to optimize the system parameters, and the optimized front and rear suspension stiffness and damping coefficient were obtained. The simulation validation of the optimized model shows that the ride comfort of the electric vehicle driven by front and rear axle dual motors is improved, and the root mean square value of the weighted acceleration at the optimized seat is significantly reduced. The theoretical optimum value is only 43.8% of that before the optimization, which is within the comfort limit. The mean square root values of the weighted acceleration at the foot and back are also reduced to some extent, and the theoretical optimum values are 42.1% and 44.0% of those before optimization, respectively. [ABSTRACT FROM AUTHOR]

To improve the fuel economy of hybrid electric vehicles (HEVs), an optimization of equivalent fuel consumption minimization strategy (EFCMS) was proposed based on firefly algorithm (FA). Taking the parallel hybrid electric vehicle as research object, the equivalent factor of EFCMS and the battery state of charge (SOC) were optimized by FA to realize the equivalent control. A whole vehicle model was established in Matlab/Simulink for simulation. The results show that compared with that before optimization, the fuel saving rates under three working conditions of urban dynamometer driving schedule (UDDS), new European driving cycle (NEDC) and highway fuel economy test (HWFET) can respectively reach 28.5%, 25.5% and 16.9%. Compared with the traditional algorithms, the fuel consumption of the proposed EFCMS based on FA is effectively decreased, and the battery SOC can be well maintained near the target value. [ABSTRACT FROM AUTHOR]

To solve the coordination problem between the driving anti-skid strategy and the optimal torque distribution strategy, based on the real-time particle swarm optimization algorithm, a comprehensive torque distribution strategy with the consideration of stability and economy of vehicles was proposed. The driving anti-skid strategy with slip rate as control target could output the front and rear axle torque constraints. By the particle swarm optimization with real-time optimization as optimization method and with front and rear axle torque constraints as dynamic constraint condition, the optimal torque distribution strategy could run normally when the anti-skid strategy took effect. Based on AVL-Cruise and Simulink platform, a joint simulation model of vehicle economy was established to analyze the optimization effect. The results show that under the three selected cycle conditions, the power consumption per hundred kilometers is averagely decreased by 4. 79%, and the driving mileage is averagely increased by 5. 49%. The comprehensive torque distribution strategy can improve the fuel economy on the premise of ensuring the longitudinal stability of bus. [ABSTRACT FROM AUTHOR]

To solve the problem of torque ripple in traditional direct torque control of permanent magnet synchronous motor(PMSM) for pure electric vehicle at low motor speed, a new control strategy of space vector pulse width modulation(SVPWM) was proposed based on two-level generalized inverter(TLGI) technology. The principle and implementation process of applying SVPWM technology based on TLGI to PMSM motor were discussed. The switch state function table of SVPWM was derived, and the voltage amplitude and voltage vector partition of SVPWM were investigated. Based on the new SVPWM control method, a pure electric vehicle motor was modeled and simulated by Matlab/Simulink. The simulation results of the motor control system show that the proposed method can effectively expand the SVPWM linear modulation region and shorten the system regulation time. Compared with the hysteresis control method in traditional direct torque control, the proposed control method has more advantages. [ABSTRACT FROM AUTHOR]

According to the distributed structure of common hybrid vehicle powertrains, a domestically traditional fuel vehicle was used as research platform, and a new two-axis drive hybrid vehicle powertrain was designed without changing the overall structure of original vehicle. The powertrain of original car was retained, and a complete electric drive system was installed on the rear axle. Based on the passenger car emission and energy consumption test standards and the actual operating conditions, the parameters of relevant power components of the rear axle electric drive system were matched, and the vehicle control strategy was designed. The vehicle simulation model was established by AVL-Cruise, and the vehicle performance was also simulated and analyzed. The results show that the new two-axis drive hybrid system can flexibly switch the vehicle drive mode to meet the requirements of different driving conditions. The new two-axis drive hybrid system has greater improvement in power performance than the original vehicle, and the fuel economy is 10.58% higher than that of original vehicle with significantly improved vehicle performance. [ABSTRACT FROM AUTHOR]

According to the structure of parallel hybrid electric bus (PHEB) and typical China conditions, the parallel electric auxiliary control strategy was used for the PHEB. A segmented and crossed design method of shifting schedule was proposed to select appropriate shifting schedule based on the different operation modes of PHEB and the opening degree of throttle. The vehicle model and the parallel electric auxiliary control strategy were established with the cooperation between AVL Cruise and Matlab. The simulation results show that compared with the best economic shift control strategy, the acceleration performance is improved by 6.3%, and the economy is greatly improved compared with the optimal power shift control strategy. The simulation study of dynamic performance and fuel economy demonstrates that the designed shifting schedule can ensure the vehicle dynamic performance with suitable economy. [ABSTRACT FROM AUTHOR]