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To improve the comprehensive performance of the distributed wheel-side four-wheel-drive electric bus, the problem of optimal distribution of the driving torque of the four wheel-side motors is studied. Aiming at the poor economy and failure of switching control due to the consideration of both straight and steering conditions, this paper proposes a fuzzy yaw moment control strategy based on the golden section search algorithm. Under full working conditions, according to the efficiency characteristics of the front and rear axle drive motors, the golden section search algorithm is used to determine the best front and rear axle motor torque distribution coefficient K to distribute the front and rear axle motor torques. Given the stability problems existing in the steering conditions, based on the optimal torque distribution of the front and rear axles, fuzzy control is used to calculate the expected yaw moment, and the left and right wheel torques are adjusted in real time. The simulation is carried out through TruckSim and MATLAB/Simulink, and a hardware-in-the-loop platform is built for experimentation under step steering conditions and sine wave steering conditions. The results show that the proposed torque optimal distribution strategy can optimally distribute the torque of the four drive motors through the real-time identification of working conditions. Compared with the four-wheel equal distribution, under two different steering conditions, the torque distribution efficiency of the torque distribution strategy using the golden section search algorithm increased by 4.35% and 3.83%, respectively. The energy utilization rate of the whole vehicle is improved under all of the working conditions. Under steering conditions, compared with the four-wheel equal distribution and the torque distribution strategy using the golden section search algorithm under all of the conditions, the yaw rate deviation and the slip angle deviation can be reduced, and the yaw stability has been improved.

For intelligent four-wheel-drive (4WD) electric vehicle (EV), the vehicle speed can be planned and controlled for energy saving based on the slope information of road ahead. To reduce the calculation load of the optimisation algorithm, the model predictive control (MPC) method is formulated based on the time horizon in this study. Furthermore, a fast gradient method based control tool-GARMPC is used to solve the optimisation problem. First, the longitudinal dynamics model of 4WD EV based on time horizon and distance horizon is established based on the road slope information, respectively. Second, the MPC problem based on the time-discrete model is formulated and solved by GARMPC tool. For comparison, a dynamic program (DP) control method is introduced based on the distance-discrete model. Finally, the simulation is conducted under a designed road condition and a real measured road condition. The results show that the time-horizon based MPC method can significantly reduce the energy consumption compared with the proportion integration differentiation control method, which is similar to the driver's operation. Compared with the DP optimisation method, the time-based MPC method reduces the calculation time to smaller than 1 ms, which is essential for real-time application in a road vehicle.

For performance improvement of modern vehicle dynamic control systems, exact knowledge of the vehicle motion state and the road conditions is essential. Addressing this problem, the development and...

In this paper, a novel hybrid vehicle chassis is designed without assisted steering system and its kinematics model, dynamics model as well as a model of the control system. The existing steering mechanism does not provide enough torque or has a shortage of mechanical strength and control. The proposed design has the capability to solve these problems easily. In the first part of this study, the design and development of the vehicle are introduced. After that, a new 4-wheel-drive (4WD) hybrid vehicle chassis including a vehicle platform, a control device, and self-steering mechanism is designed. Its kinematics and dynamics models are built. Furthermore, to optimize the control model and linkage are added between the front and rear bodies. In addition, the new hybrid vehicle chassis has been tested in actual driving. The reliability and feasibility of the vehicle are evaluated by UG software. The open-loop simulation for validation is performed by MATLAB. Finally, traditional proportion-integration-differentiation (PID) control system of the improved model of vehicle chassis is presented. Therein, the PID feedback control loop was employed to track the reference torque of 4-independent wheels. The results are verified using the real-time vehicle. The proposed design is proved feasibility not only has a small turning radius but also has a high control precision, which ensures the flexibility of the vehicle and can control the direction as well. In addition, the proposed design is best for modern agricultural vehicle and can be implemented in commercial and private vehicles.

In the braking process of double-motor electric vehicle, Both front and rear axles can both output regenerative braking force to recover braking energy, In order to study the influence of the ratio of braking force distribution between front and rear axes on the braking energy recovery, In this paper, three different braking force distribution schemes are designed on the premise of ensuring the braking stability of road surface with low adhesion coefficient, and through AVL-Cruise and MATLAB-Simulink to do the Co-simulation. Simulation results underCLTC-P condition show that, the energy recovery of the f curve control strategy, which maximizes the front axle braking force ratio, is higher than that of the other two control strategies, reaching 62.25%.

Vehicle autonomous present a major important problem for modern commercialized four wheel drive electric vehicle (4WDEV) propulsion system. The supply of electric vehicles with batteries is limited by state of charge (SOC) and the type of batteries technologies used. To overcome problem of energy variation in several speed and road topology condition, the proton exchange membrane fuel cells (PEMFC) is presented as best solution of energy management. In this paper we focus the behavior of PEMFC for 4WDEV controlled by direct torque control based space vector modulation (SVM-DTC). The proposed controller law is very appropriate to electric traction systems. To test the performances of PEMFC, we undergo 4WDEV to several tests. Direct torque control based on space vector modulation (SVM-DTC) is proposed. The Obtained results under Matlab/Simulink present satisfactory. The DTC-SVM law increases the utility 4WDEV autonomous under several scenario considerations. Moreover, the future industrial's vehicle must take into considerations the obtained results into design steps.

At the state-of-the-art, electric propulsion systems based on hub-motors allow mechanical components to be removed, increasing also the vehicle stability. However, since motors and wheels are directly coupled, when a high propulsion torque is delivered, in such a configuration the motors could work in low efficiency operative points, negatively affecting the vehicle consumptions. In this paper, a torque distribution strategy is defined to minimize these consumptions. The propulsion configuration under investigation is a four-wheel drive that adopts two different couples of Brushless DC (BLDC) hub motors. The proposed research highlights how the electric efficiency is improved when the propulsion torque required by the vehicle is delivered by the BLDCs in an asymmetric way, according to the motors operative conditions. Since this torque repartition dynamically changes while the vehicle is running, the effects on the vehicle stability are also evaluated. Such an analysis is performed considering, as reference, a Class A vehicle, principally designed for the urban mobility.

A relatively new technology for the electric vehicles considers the use of brushless permanent magnet motors directly connected to the car wheels (in-wheel motors or hub motors). In order to evaluate the performance that can be obtained, a complete dynamic model of a four-wheel drive (4WD) electric vehicle equipped with four in-wheel motors is developed and a correspondent parametric simulator is implemented in Matlab/SimulinkTM. The simulator is also employed for designing, testing and comparing various control logics which reproduce the handling behavior of a real vehicle.

According to the characteristic that each wheel torque of 4WD electric vehicle is independent controllable, the control allocation method with hierarchical structure to optimize the distribution of motor torque can improve the handling stability of the vehicle. The controller is composed of an upper controller and a lower distributor, of which the upper controller can calculate the generalized force of longitudinal force and yaw moment that the vehicle needed based on the vehicle state, and the lower controller is used to figure out the torque allocated to each wheel. The whole vehicle and steering system models are established for simulation and demonstration through the application of Matlab and Simulink. The simulation results show that the control allocation method with hierarchical structure can effectively improve the handling stability of the vehicle.

Each wheel torque can be controlled independently, so four-wheel-drive electric vehicle can not only control the vehicle stability through hydraulic braking pressure regulation, but also through controlling the motor driving and braking force to generate yaw moment, which are different with the conventional vehicles. 4WD Evs have potential applications in control engineering. Both in-wheel motors and the EHB are actuators for vehicle stability control. In this paper, a vehicle co-simulation platform is constructed through the application of AMEsim and Simulink, additionally, a fuzzy controller is designed to generate yaw moment so as to compensate for deviations between CG slip angles and yaw rate. The simulation results show that the stability control system with motors and a mechanical load brake system can effectively improve the handling stability of the vehicle.

Regenerating braking technology benefits energy economy of vehicle, being and the important way to improve the energy saving and emission reduction of electric vehicles. To guarantee braking safety and maximize regenerative braking energy, considering the constraints of motor and battery on energy recovery, a strategy of regenerative braking of twin motor 4WD electric vehicle is provided by braking force distribution via I-curve and ECE regulatory curve. A vehicle system simulation model combining the vehicle model and the braking force distribution control model is built. Through the analyses for the strategy braking performance under braking conditions, the results verify the feasibility of control strategy, enabling improving the range of electric vehicles and recovering regenerative braking energy effectively in the case of stability and safety.

Vehicle stability control is one of control strategy to improve yaw stability of the 4 wheel drive electric vehicle (4WD EV). The main purpose of this control strategy is to enhance the vehicle handling and stability such that satisfy the occupant safety even though in the critical condition. The control strategy consists of multi layer control loops. The upper control loop, which employs adaptive sliding mode control, is responsible to specify control effectors required for keeping 4WD EV yaw stability. Moreover, the lower control loop, which is responsible to determine actual control to every actuator, is employed dynamic control allocation. By using this proposed configuration, the control performance is improved, since the upper control loop is developed with an adaptation tuning approach and can deal with unknown but bounded system uncertainties. The proposed method have been successfully proved by using Lyapunov theory to ensure its stability. The simulation results show that the proposed strategy can improve the handling stability of 4WD EV, even though it drives in various conditions.

Taking the independent four motorized wheels driving electric vehicle (4WD EV) as study object, the method and index evaluating ride comfort of automobile suspension system were described, and the input model of random road excitation and the dynamics model of 1/4 vehicle vibration system were established, then the simulation of ride comfort of the established model was conducted, so the evaluating indexes’ responses in time domain and frequency domain were obtained. Above all, the changes of these indexes which are suspension damping, spring stiffness and un-sprung mass were analyzed, their effects on the ride comfort of electric vehicle driven by motorized wheel studied, thus provided reference for the development of electric vehicle driven by in-wheel motor.

The performance test of four different martial lead acid (Li-Acid), Nickel cadmium (Ni-Cd), lithium-ion (Li-Ion) and nickel metal hydride (NiMH) batteries for 4WD electric vehicle under several speeds variation constraints are presented in this paper. The battery materials model choice is a key item, and thanks to an increasing importance on vehicle range and performance, the Li-Acid, Ni-Cd,Li-Ion and NiMH batteries could become a viable candidate that’s our proposal battery model in the present work , in this way the present paper show a novel strategy of 4WD electrical vehicle power electronics studies when the current battery take into account the impact of the direct torque based space vector modulation technique (DTC-SVM) in the several speed variations using the primitive battery SOC of 75 % state. The speed of four wheels is calculated independently during the turning with the electronic differential system computations which distributes torque and power to each in-wheel motor according to the requirements, adapts the speed of each motor to the driving conditions This paper focuses lead acid ,Lithium-ion and NiMH Batteries controlled by Buck Boost DC-DC converter power supply for EV. The performances of the proposed strategy controller give a satisfactory simulation results. The proposed control law increases the utility EV autonomous under several roads topologies.

Four-Wheels-Drive (4WD) electric Vehicle (EV) controlled with Direct Torque Control based Space Vector Modulation (DTC-SVM) is presented, where the electrical traction chain was well analyzed and studied from the lithium battery, the buck boost to the mechanical load behavior. The speed of four wheels is calculated independently during the turning with the electronic differential system computations which distributes torque and power to each in-wheel motor according to the requirements, adapts the speed of each motor to the driving conditions. The basic idea of this work is to maintain the initial battery state of charge (SOC) equal to 70% and the prototype was tested in several topology conditions and under speed. The simulations carried in Matlab/Simulink verified the efficiency of the proposed DTC-SVM controller, and show that the system has more favorable dynamic performance. Results also indicate that this strategy can be successfully implemented into the traction drive of the modern 4WD electric vehicles.

A novel speed control design of 4WD electric vehicle (EV) to improve the comportment and stability under different road constraints condition is presented in this paper. The control circuit using intelligent adaptive fuzzy PI controller is proposed. Parameters which guide the functioning of PI controller are dynamically adjusted with the assistance of fuzzy control. The 4WD is powered by four motors of 15 kilowatts each one, delivering a 384 N.m total torque. Its high torque (338 N.m) is instantly available to ensure responsive acceleration performance in built-up areas. The electric drive canister of tow directing wheels and tow rear propulsion wheels equipped with tow induction motors thanks to their light weight simplicity and their height performance. Acceleration and steering are ensure by electronic differential, the latter control separately deriving wheels to turn at any curve. Electric vehicle are submitted different constraint of road using direct torque control. Electric vehicle are simulated in MATLAB SIMULINK. The simulation results have proved that the intelligent fuzzy PI control method decreases the transient oscillations and assure efficiency comportment in all topologies road constraints, straight, curved road, descent.

Direct yaw moment control can maintain the vehicle stability in critical situation. For four-wheel independently driven (4WD) electric vehicle with in-wheel motors (IWMs), direct yaw moment control (DYC) can be easily achieved. A fairly accurate calculation of the required yaw moment can improve vehicle stability. A novel sliding mode control (SMC) technique is employed for the motion control so as to track the desired vehicle motion, which is it for different working circumstances compared to the well-used traditional DYC. Through the weighted least square algorithm, the lower controller is used to determine the torque properly allocated to each wheel according to the desired yaw moment. Several actuator constraints are considered in the control strategy. In addition, a nonlinear tire model is utilized to improve the accuracy of tire lateral force estimation. Then, simulations are carried out and the values of vehicle states are compared. The simulation results show that the control system proposed can effectively improve the handling stability of the vehicle.

In-wheel motors have tremendous potential to create an advanced all-wheel drive system. In this paper, a novel power assisted steering technology and its torque distribution control system were proposed, due to the independent driving characteristics of four-wheel-independent-drive electric vehicle. The first part of this study deals with the full description of the basic theory of differential drive assisted steering system. After that, 4-wheel-drive (4WD) electric vehicle dynamics model as well as driver model were built. Furthermore, the differential drive assisted steering control system, as well as the drive torque distribution and compensation control system, was also presented. Therein, the proportional–integral (PI) feedback control loop was employed to track the reference steering effort by controlling the drive torque distribution between the two sides wheels of the front axle. After that, the direct yaw moment control subsystem and the traction control subsystem were introduced, which were both employed to make the differential drive assisted steering work as well as wished. Finally, the open-loop and closed-loop simulation for validation were performed. The results verified that, the proposed differential drive torque assisted steering system cannot only reduce the steering efforts significantly, as well as ensure a stiffer steering feel at high vehicle speed and improve the returnability of the vehicle, but also keep the lateral stability of the vehicle.

This paper proposes a wheel slip control strategy for 4WD Electrical Vehicle with In-wheel Motors. In the first part of this paper, a brief introduction of sliding mode control for acceleration slip regulation is given. Consider that its control effect varies with road conditions, another algorithm which can automatically adapt to different roads is designed. This method takes advantage of the peculiarity of the longitudinal static tire force curve and regulates wheel slip ratio to the detected optimal value, aiming to maximize the traction force while preserving sufficient lateral tire force. Simulation results show that the slip rate can be regulated to a value around the optimal slip ratio, and the driving torque is very close to the maximum transmissible torque. The control strategy achieves stronger stability, shorter driving distance and hence better control performance.