Torque Distribution Control Research Articles

Automatic determination of directional stability parameters of an electric vehicle with a two-motor scheme as part of the torque distribution controller

In case if the front and rear axle of the electric vehicle are not mechanically linked, the presence of automatic torque distribution to the axles or wheels becomes not only an addition to increase the level of consumer properties, but also a necessity. A method for determining the directional stability condition of an electric four-wheel drive vehicle is developed as part of the research by comparing the target and measured yaw rate, and is based on the formulated conditions of drift, skid, and counter steer registration. A method for detecting slipping of the driving wheels of an electric vehicle with a dual-motor scheme is developed, which is based on comparing the target and measured velocity differences of the front and rear axle and includes an auto oscillation detection function. A method for determining the target front and rear axle speed difference in a corner is described. Based on the tests performed, it is concluded that the proposed methods are applicable to the active torque distribution function between the axles of an all-wheel drive electric vehicle being developed by the authors of the paper, which provides improved directional stability and controllability, and counteracts slipping of the drive wheels.

Stability coordinated control strategy of autonomous unmanned 4WID-4WIS vehicle based on APD-LQR and AFSMC

To improve the four-wheel independent driving and four-wheel independent steering (4WID-4WIS) autonomous unmanned vehicles’ active safety performance at their maximum operating capacity, the control of path following, four-wheel steering (4WS) and lateral stability should be coordinated. This paper introduces a hierarchical coordinated control framework, in which several independent controllers collaborate to enhance the overall performance of the vehicle system. Initially, in the upper controller, an adaptive preview distance linear quadratic regulator (APD-LQR) path following algorithm is proposed, considering the dynamic characteristics of the tire. It aimed at making the following error converge and obtaining the optimal front wheel steering angle. Meanwhile, an adaptive fuzzy sliding mode control (AFSMC) algorithm is implemented for obtaining additional yaw moment. It aimed at coordinating and improving effectively path following performance and lateral stability. Using the phase plane approach, the sliding surface is dynamically modified. Subsequently, in the lower controller, a rear wheel angle controller based on vehicle speed is proposed. It aimed at further enhancing vehicle’s maneuverability and stability by fully utilizing its steering redundancy features. Moreover, a torque distribution controller establishes a comprehensive cost function and then the NSGA-III algorithm is employed to optimize the torque distribution coefficients. Finally, simulation and Hardware-in-Loop (HIL) test results demonstrates that the proposed coordination algorithm can fully utilize the redundancy features of the 4WID-4WIS vehicle, and significantly enhances the vehicle’s path following accuracy and lateral stability, especially under extreme driving conditions.

Torque distribution of distributed drive electric vehicle based on efficiency map of drive system

Abstract In order to optimize the system efficiency of distributed drive electric vehicles, based on the MAP of the efficiency of the drive motor system, the objective function of the optimal efficiency is established, and the problem of the no-load loss of the drive motor is considered. A torque distribution control strategy method considering the no-load loss of the motor is proposed. Then, AVL CRUISE and Simulink are used to establish a joint simulation platform, and a comparative simulation test analysis is carried out under ECE conditions. The simulation results show that the torque distribution strategy considering the loss makes the distributed drive motor work in a relatively high efficiency range. Compared with the torque distribution strategy without considering the loss, the power consumption is reduced by 3.4%, which effectively improves the vehicle economy. The research results can provide a reference for system efficiency optimization of distributed drive electric vehicles.

Adaptive differential steering strategy for distributed driving unmanned ground vehicle with variable configurations based on modified localized modelling sliding mode control

When performing complex tasks such as position transfer and material transportation, the distributed driving unmanned platform with variable configurations needs to address the challenge of multi-wheel cooperative torque distribution control to achieve high-performance differential steering and enhance vehicle dynamics. The configuration change will impact the dynamic performance of the unmanned platform, posing a challenge to the performance of the existing control strategy based on mathematical model development. In order to address the aforementioned issues, this paper analyzes the impact of changes in vehicle configuration on steering gain and proposes a hierarchical adaptive differential steering strategy based on variable vehicle configurations. Firstly, the response characteristics of the yaw angle relative to the active yaw moment under the influence of changes in wheelbase and tread are analyzed. Based on this analysis, two structural modes, maneuverable and balanced, are selected. Secondly, a localized-modelling sliding mode control method with an extended state observer is proposed to estimate the desired yaw moment in the upper controller, considering the motor's execution delay. Then, the lower controller optimizes the torque of each wheel in real-time using the whale optimization algorithm. It aims to optimize tire energy dissipation and tire load rate while ensuring driving stability and achieving differential steering. Finally, through co-simulation and experiments on a scaled prototype, the reliability of the dynamics theory and the superiority of the control algorithm are validated. This optimization has led to significant improvements in the tire dissipation energy index and tire load rate index.

Coordinated torque control for enhanced steering and stability of independently driven mobile robots

PurposeMobile robots with independent wheel control face challenges in steering precision, motion stability and robustness across various wheel and steering system types. This paper aims to propose a coordinated torque distribution control approach that compensates for tracking deviations using the longitudinal moment generated by active steering.Design/methodology/approachBuilding upon a two-degree-of-freedom robot model, an adaptive robust controller is used to compute the total longitudinal moment, while the robot actuator is regulated based on the difference between autonomous steering and the longitudinal moment. An adaptive robust control scheme is developed to achieve accurate and stable generation of the desired total moment value. Furthermore, quadratic programming is used for torque allocation, optimizing maneuverability and tracking precision by considering the robot’s dynamic model, tire load rate and maximum motor torque output.FindingsComparative evaluations with autonomous steering Ackermann speed control and the average torque method validate the superior performance of the proposed control strategy, demonstrating improved tracking accuracy and robot stability under diverse driving conditions.Research limitations/implicationsWhen designing adaptive algorithms, using models with higher degrees of freedom can enhance accuracy. Furthermore, incorporating additional objective functions in moment distribution can be explored to enhance adaptability, particularly in extreme environments.Originality/valueBy combining this method with the path-tracking algorithm, the robot’s structural path-tracking capabilities and ability to navigate a variety of difficult terrains can be optimized and improved.

Research on Stability Control of Distributed Drive Vehicle with Four-Wheel Steering

The four-wheel steering distributed drive vehicle is a novel type of vehicle with independent control over the four-wheel angle and wheel torque. A method for jointly controlling the distribution of the wheel angle and torque is proposed based on this characteristic. Firstly, the two-degrees-of-freedom model and ideal reference model of four-wheel steering vehicle are established; then, the four-wheel steering controller and torque distribution controller are designed. The rear wheel angle is controlled by the feedforward controller and the feedback controller. The feedforward controller takes the side slip angle of the center of mass as the control target, and the feedback controller takes the yaw angle as the control target. Torque is controlled by two control layers, the additional yaw moment of the upper layer is calculated by the vehicle motion state and fuzzy control theory, and the lower layer distributes wheel torque through the road adhesion coefficient and wheel load. Finally, a simulation platform is established to verify the effectiveness of the proposed control algorithm.

Wheel Torque Distribution Control Strategy for Electric Vehicles Dynamic Performance With an Electric Torque Vectoring Drive Axle

The ability of active chassis control for dynamic performance improvement of electric vehicles with centralized drive system is limited duo to the driving torque between two-side wheels always equally distributed. To solve this problem, this paper proposes a novel electric torque vectoring (TV) drive-axle and its torque distribution control strategy, which can realize the function of arbitrary distribution of the left/right wheel driving torque in the form of centralized drive, thereby improving the dynamic performance of the vehicle. First, the structure and torque distribution principle of TV drive-axle are analyzed theoretically. Subsequently, an accurate mathematical model of TV drive-axle is established based on bond graph theory. Next, a wheel torque distribution control strategy of TV drive-axle is proposed based on hierarchical control approach to improve the vehicle’s handling stability. Wherein, the target yaw rate motion tracking controller as the upper-level controller is designed based on the second-order super-twist sliding mode control (SS-SMC) algorithm, and the wheel drive anti-slip controller in lower-level is used to restrict possible wheels slipping. Finally, the off-line simulation and hardware-in-the-loop (HIL) experiment results suggest that the proposed novel TV drive-axle and control strategy can significantly improve the handling stability and steering flexibility of the vehicle.

Optimal Predictive Torque Distribution Control System to Enhance Stability and Energy Efficiency in Electric Vehicles

This article presents a novel approach to address the critical issues of stable rotation and energy efficiency in electric vehicles (EVs). To achieve these objectives, we propose a comprehensive control system that leverages the power of optimization through optimal predictive control methods. The central idea revolves around minimizing the predicted tracking error for future time steps by intelligently determining control inputs. In this innovative approach, we emphasize the dynamic adjustment of weight coefficients and optimization of wheel torque to strike a delicate balance between energy consumption and enhanced vehicle stability. The result is an adept controller that not only ensures vehicle stability but also significantly reduces energy consumption. Given the inherent limitations of electric motors, especially in terms of torque during vehicle operation, and the growing importance of energy conservation, our method tailors weight coefficients to generate optimal wheel torque. This ensures that the electric motors operate within their power range, thereby minimizing energy consumption and extending the overall efficiency of EVs. The combination of stable rotation and energy efficiency offered by this control system represents a promising step forward in the realm of electric vehicles, making them more sustainable and environmentally friendly while maintaining the high standards of performance and safety that consumers expect.

Hybrid Electric Vehicle Torque Distribution Control Method and System with Environmental Temperature Protection Battery Integration

Hybrid Electric Vehicle Torque Distribution Control Method and System with Environmental Temperature Protection Battery Integration

Research on Path Tracking and Yaw Stability Coordination Control Strategy for Four-Wheel Independent Drive Electric Trucks

Achieving accurate path tracking and vehicle stability control for four-wheel independent drive electric trucks under complex driving conditions, such as high speed and low adhesion, remains a major challenge in current research. Poor coordination control may cause the vehicle to deviate from its intended path and become unstable. To address this issue, this article proposes a coordinated control strategy consisting of a three-layer control framework. In the upper layer controller design, establish a linear quadratic regulator (LQR) path tracking controller to ensure precise steering control by eliminating steady-state errors through feedforward control. The middle layer controller utilizes the fractional order sliding mode control (FOSMC) yaw moment controller to calculate the additional yaw moment based on the steering angle of the upper input, utilizing the error of yaw rate and sideslip angle as the state variable. To collectively optimize the control system, establish a coordinated optimization objective function and utilize the hybrid genetic-particle swarm optimization algorithm (GA-PSO) to optimize the weight coefficient of LQR and sliding mode parameters of FOSMC, effectively improving the performance of the controller. In the lower layer torque distribution controller, use the quadratic programming method to achieve real-time optimal torque distribution based on tire utilization, which improves vehicle stability control. Through simulations conducted under four different working conditions, the proposed control scheme demonstrates a 15.54% to 23.17% improvement in tracking performance and a 10.83% to 23.88% optimization in vehicle driving stability compared to other control methods. This scheme provides a theoretical reference for path tracking and stability control in four-wheel independent drive electric trucks.

Control Strategy of Torque Distribution for Hybrid Four-Wheel Drive Tractor

Based on the analysis of the operating conditions of the tractor, a Hybrid four-wheel drive tractor is proposed, and formulate the torque distribution control strategy based on fuzzy control, to control the driving wheel slip rate of the Hybrid four-wheel drive tractor in the high traction efficiency operating range of the tractor. The vehicle model of the Hybrid four-wheel drive tractor is established in AVL-CRUISE software, and the torque distribution control strategy based on fuzzy control is established in MATLAB/Simulink software. The AVL-CRUISE and MATLAB/Simulink co-simulation was carried out based on the plowing condition of the tractor. The simulation results show that the torque distribution control strategy based on fuzzy control can control the driving wheel slip rate of the Hybrid four-wheel drive tractor in the high traction efficiency operating range, the power performance of the Hybrid four-wheel drive tractor is improved, while the engine runs smoothly and is always in the high-efficiency range of engine operation, and the economy is better.

Adhesion control strategy for trains with driven independently rotating wheels considering active guidance

AbstractThis article presents a torque distribution control strategy for electrical trains equipped with driven independently rotating wheels (DIRW) to realise the coordination of guidance control and adhesion control. For DIRW, active guidance control is required to restore self‐centring ability. Besides, the adhesion condition determines the wheel‐rail tangential force, affecting the realisation of the guidance function. A zero lateral displacement guidance control based on an active disturbance rejection controller and an adhesion control based on optimal adhesion coefficient utilisation are applied. According to the wheel‐rail adhesion state, several torque distribution rules are designed. The primary principle of rule design is to ensure the normal operation of trains, that is, to avoid the occurrence of train idling/sliding. Next, the self‐centring function should be achieved. Finally, the train traction/braking performance should be as close as possible to the requirements of the traction/braking characteristic curve determined by the driver handle instruction. The torque distribution strategy proposed can achieve the traction/braking and guidance function on the adhesion limit. The control performance is verified through MATLAB/Simulink‐SIMPACK co‐simulation.

A yaw stability-guaranteed hierarchical coordination control strategy for four-wheel drive electric vehicles using an unscented Kalman filter

A novel hierarchical coordination control strategy (HCCS) is offered to guarantee the stability of four-wheel drive electric vehicles (4WD-EVs) combining the Unscented Kalman filter (UKF). First, a dynamics model of the 4WD-EVs is established, and the UKF-based estimator of sideslip angle and yaw rate is constructed concurrently. Second, the equivalent cornering stiffness coefficients are jointly estimated to consider the impact of vehicle uncertainty parameters on the estimator design. Afterwards, a HCCS with two-level controller is presented. The sideslip angle and yaw rate are controlled by an adaptive backstepping-based yaw moment controller, and the computational burden is relieved by an improved adaptive neural dynamic surface control technology in the upper-level controller. Simultaneously, the optimal torque distribution controller of hub motors is developed to optimize the adhesion utilization ratio of tire in the lower-level controller. Finally, the proposed HCCS has shown effective improvement in the trajectory tracking capability and yaw stability of the 4WD-EVs under various maneuver conditions compared with the traditional Luenberger observer-based and the federal-cubature Kalman filter-based hierarchical controller.

All-in-One Control Framework for Distributed Drive Electric Buses Path Tracking Subject to Uncertain Crosswind and Varied Passenger Mass

This paper proposes an all-in-one control framework for distributed drive electric buses (DDEBs) that can effectively attenuate the effects of uncertain crosswind and varied passenger mass in path tracking, while minimizing the electricity consumption of battery. To track the desired path and ensure driving stability, a robust tube-based model predictive control method is proposed considering lateral, yaw and roll motions. Simultaneously, for the longitudinal motion, a robust sliding mode control method is designed to achieve accurate tracking of longitudinal velocity. Meanwhile, the uncertain crosswind and varied passenger mass faced by the DDEBs are decoupled into external disturbances and their effects on the system are eliminated in both controllers. Then, to cope with energy optimization problem in path tracking, a torque distribution controller is constructed by formulating the vehicle stability margin, tracking dynamic requirements and energy efficiency as constrained weighted least squares problem. Finally, a Trucksim-Simulink co-simulation is performed, where the simulation results demonstrated that the proposed control framework is robust and effective, and can achieve better energy saving effect compared to the original control methods.

Path-following and tire loss investigation of a front in-wheel-drive electric vehicle with off-centre CG

Electric Vehicles (EVs) are becoming an inimitable answer to the problem of transport sector pollution. The inherent potential of individual wheels’ control makes in-wheel-drive EVs even more advantageous. This paper investigates the dynamics control of a laterally off-centre CG (Centre of Gravity) electric vehicle as a real-world practice, nevertheless ignored. Apart from dynamic performance, tires’ loss as a representative of their wear and hence TWP (Tire Wear Particle) emission is analysed. In this regard, mathematical modelling of an eight-degree-of-freedom electric vehicle with eccentric CG is pioneered. The model is used to develop a novel control strategy which calculates torque distributions for the front-left and right in-wheel motors. The ideal torque distribution satisfies the torque demand as well as perfect reference yaw rate tracking. Simulation results for two straight and cornering scenarios reveal that while almost removing path-following error, a properly designed torque distribution controller could potentially cancel up to nearly 5% of tires’ wear compared to three other rival strategies.

EV Smart Regeneration using Super Capacitor with Battery Bank

A EV is defined as a vehicle that can be powered by an electric motor that draws electricity from a battery and is capable of being charged from an external source. The biggest factor that determines the range of an EV is the capacity of the lithium-ion battery in the car. This paper proposes a real time optimal driving torque distribution strategy for an electric vehicle (EV) with independently driven front and rear wheels. The proposed optimal torque distribution strategy among the front and rear wheels, improves the overall energy efficiency of the vehicle, there by increasing the driving range achievable per charge cycle of the EV. The torque is optimized with the objective of minimizing the energy consumption during driving as well as maximizing the regenerative energy recuperation during the braking. Here, a real time torque distribution control system is proposed which can realize optimal distribution of driving-braking torque corresponding to the driving commands, for constant speed driving, acceleration, braking and grade climbing driving modes. The optimal torque distribution ensures minimal energy consumption, thus improving the energy efficiency of the EV. By reducing the energy consumption the driving range achievable per charge cycle is improved, realizing range extension of EV.

Effects of transfer case structural parameters on torque transmission based on thermoelastic instability

Based on the theory of thermoelastic instability, the thickness trend of lubricating oil film on the surface of the transfer case friction pair is studied, and the basic process is obtained in which the film thickness changes due to thermoelastic instability. Firstly, the dynamic simulation model of the transfer case is established, Secondly, since the thickness of the transfer case lubricating oil film is affected by the joint action of lubricating oil pressure, contact pressure and thermal expansion, this paper discusses the condition of thermoelastic instability of the transfer case torque transmission. The result shows that the critical speed of the thermoelastic instability increases correspondingly with the increase of the thickness of the oil film. The critical curve divides the engagement process into two parts, namely the stable region at the upper part of the curve and the unstable region at the lower part of the curve; then the thermoelastic instability region of the torque transfer of the transfer case is calculated. Next, in order to further analyze the influence of thermoelastic instability on the characteristics of the transfer case, three factors—the surface roughness of the friction plate, the lubricating oil viscosity, and the thermal conductivity of the dual steel disc—are mainly analyzed, which shows that thermoelastic instability does affect the critical speed and torque transmission of the transfer case. The conclusion is expected to be applied to the engineering practice of torque distribution control of the transfer case.

Coordinated control algorithm of lateral stability of hybrid electric commercial vehicle

Focusing on the problem of mutual interference between the vehicle controller and the lateral stability control system in the stability control of hybrid electric vehicles (HEV), this study proposes a coordinated control algorithm for hybrid power systems and lateral stability, which can meet the real-time control requirements of the vehicle stability. First, the overall architecture of coordinated control between the hybrid power system and the vehicle lateral stability control system is designed. The judgment logic of lateral stability control system intervention and exit is determined on this basis. Second, in the upper layer of the control algorithm, the model predictive control algorithm is used to calculate the additional yaw moment required to maintain stability control under lateral instability of the vehicle with the vehicle two-degrees-of-freedom model as a reference. The motor output torque control and braking force distribution are then carried out in the lower layer of the control algorithm. The target braking wheel is determined according to the oversteering and understeering state of the hybrid vehicle. The additional yaw torque distribution control is formulated based on the quadratic programing algorithm. The strategy is to perform dynamic compensation for unstable or critically unstable vehicles to solve the optimal control problem under multiple constraints. Finally, through Matlab/Simulink and Trucksim co-simulation and hardware-in-the-loop test, the validity and real-time performance of the control algorithm proposed are verified to solve the interference problem in the lateral stability control process of HEVs and further improve the stability of vehicle rideability and active safety.

Torque Distribution Control Strategy of Electric Wheel Loader with Multiple Drive Motors Based on Optimal Motor Efficiency

<div>Wheel loaders are widely used in construction projects. In order to reduce pollution and energy consumption, major wheel loader manufacturers are developing electric powertrain technology. Our main research goal is to reduce the energy consumption of a pure electric loader. This study is intended to build a vehicle simulation model of a multiple drive motor electric loader. According to the common working conditions and empirical formulas of the loader, the simulation data of the electric loader are calculated. The torque distribution control strategy based on the optimal efficiency of the motor is designed for the multiple drive motor electric loader and is compared with the equal proportion distribution control and the axle load ratio distribution control through simulation analysis. The simulation results show that the proposed torque distribution control strategy based on motor optimal efficiency can reduce energy consumption by 7–12%.</div>

Hybrid Electric Vehicle Torque Distribution Control Method and System with Environmental Temperature Protection Battery Integration

This research presents a hybrid electric vehicle (HEV) torque distribution control method and system that incorporates an environmental temperature protection battery. The study involves the collection of ambient temperature information to determine the vehicle's location and utilizes a battery equivalent circuit model to calculate the actual temperature of the battery. The state of charge (SoC) values of the battery are determined based on battery energy dump and maximum capacity. The research utilizes a neural network control method to optimize control parameters considering the actual temperature and SoC values of the battery. Furthermore, an online minimum equivalent oil consumption strategy is developed to model the target function and constraint formulas for fuel consumption, which enables the determination of optimal motor torque values during equivalent fuel consumption. The torque distribution and control commands for the vehicle's power train and dynamics module are established based on the calculated engine torque and motor torque values. By considering battery behavior and controlling the power-driven system, the research aims to protect against galvanic actions and demonstrates its practical significance.