Direct Yaw-moment Control Controller Research Articles

Integrated Four-Wheel Steering and Direct Yaw-Moment Control for Autonomous Collision Avoidance on Curved Road

<div>An automatic collision avoidance control method integrating optimal four-wheel steering (4WS) and direct yaw-moment control (DYC) for autonomous vehicles on curved road is proposed in this study. Optimal four-wheel steering is used to track a predetermined trajectory, and DYC is adopted for vehicle stability. Two single lane change collision avoidance scenarios, i.e., a stationary obstacle in front and a moving obstacle at a lower speed in the same lane, are constructed to verify the proposed control method. The main contributions of this article include (1) a quintic polynomial lane change trajectory for collision avoidance on curved road is proposed and (2) four different kinds of control method for autonomous collision avoidance, namely 2WS, 2WS+DYC, 4WS, and 4WS+DYC, are compared. In the design of DYC controller, two different feedback control methods are adopted for comparison, i.e., sideslip angle feedback and yaw rate feedback. The simulation results demonstrate significant improvements in the path tracking performance and stability of the 4WS+DYC control system compared to other control systems. Furthermore, the performance of the DYC control system with yaw rate feedback outperforms that of the DYC control system with sideslip angle feedback.</div>

Coordinated control of AFS and DYC for electric vehicles with mechanical elastic electric wheels considering the roll effects and uncertain parameters

In order to improve the lateral stability of in-wheel motors electric vehicles (IMEV) equipped with mechanical elastic electric wheels (MEEW) under extreme conditions, this paper proposes an integral sliding mode control (ISMC) algorithm based on the coordination of active front steering (AFS) and direct yaw moment control (DYC) considering the roll effects and the uncertainty of tire cornering stiffness. Firstly, the AFS control algorithm based on adaptive integral terminal sliding mode is proposed, which uses radial-basis-function neural network (RBFNN) to adaptively approximate the integrated nonlinear unknown disturbance. Secondly, considering the roll effects and uncertain cornering stiffness, a mismatched uncertain system for integrated control of AFS and DYC is established. An integral sliding mode control algorithm based on linear matrix inequality (LMI) is designed, and the asymptotic stability of sliding mode dynamics is proved. Further, a constraint optimization algorithm is used to distribute the additional yaw moment. Then, a coordinated control strategy based on the elliptical stable region of the phase plane and the rollover index is designed to activate the integrated controller of AFS and DYC at the right time. Finally, the effectiveness of the control algorithm is verified by high-fidelity CarSim-Matlab simulations. The results show that the proposed controller can effectively and robustly ensure the vehicle lateral stability under extreme conditions.

Handling and Stability Integrated Control of AFS and DYC for Distributed Drive Electric Vehicles Based on Risk Assessment and Prediction

How to improve the trajectory following ability and lateral stability under extreme conditions is an important research problem for distributed drive electric vehicles (DDEVs). This paper proposes a novel integrated control architecture of active front steering control (AFS) system and direct yaw moment control (DYC) system for DDEVs. First, to deal with the future instability problem caused by driver’s misoperation or delayed control, online risk assessment and prediction models, including self-regulating phase plane stability judgment and future driving state prediction of vehicles, is designed to provide decision commands for actuators in advance under extreme conditions. Then, on the basis of comprehensive consideration of system chattering, robustness and control constraint index requirements, an integrated control method based on robust sliding mode predictive control (SMPC) to put forward to solve the multi-objective and multi-constraint optimization problem for multi-subsystem integration. Finally, the simulation and experimental results show that the proposed control architecture can effectively assist drivers improve the trajectory following ability and handling stability of DDEVs, as to ensure the maneuverability and safety of emergency obstacle avoidance under extreme conditions.

Coordinated Control of Active Suspension and DYC for Four-Wheel Independent Drive Electric Vehicles Based on Stability

Active suspension control and direct yaw-moment control (DYC) are widely used in the vehicle control field. To solve the coupling between those two controllers, a coordinated control of active suspension and DYC is proposed to further improve the vehicle roll and yaw stability. To enhance the adaptive ability of the active suspension, a proportional integral control optimized by the genetic fuzzy algorithm is introduced. DYC is proposed based on the sliding mode control. To restrain the chattering, the parameters of the sliding mode control is optimized by a genetic algorithm. Finally, a coordinated controller is presented based on the adaptive distribution of the anti-roll torque in the front and rear suspension. The simulation results show that the proposed active suspension and DYC can greatly improve the roll and yaw stability, respectively. The expected vehicle status can be well tracked. In addition, the coordinated control is compared by simply using two independent controllers under a different tire–road friction coefficient and different steering maneuver. The results show that the coordinated control has an even better performance under each working condition.

Design of the integrated AFS and DYC scheme for vehicles via FTSM and SOSM techniques

<p style='text-indent:20px;'>Improving the stability and safety is of great significance for the in-wheel electric vehicle. There are many studies only concentrating on active front steering (AFS) control or direct yaw-moment control (DYC). However, When the in-wheel electric vehicle is under extreme conditions, AFS or DYC alone is not effective. In this paper, an integrated controller of AFS and DYC is proposed. Firstly, the ideal values of yaw rate and sideslip angle can be calculated based on the two-degree-of-freedom vehicle model. Secondly, the AFS controller is obtained according to the backstepping-based fast terminal sliding mode (FTSM). Then, the DYC controller which consists of the upper controller and the lower controller is constructed. The upper controller is developed via the integral-based second-order sliding mode (SOSM). The appropriate torque is outputted to each wheel by the lower controller. Finally, the simulation results show that the actual yaw rate and sideslip angle can approach the ideal ones as closely as possible under the proposed integrated controller.</p>

Research on intervention criterion and stability coordinated control of AFS and DYC

To improve vehicle handling stability, an intervention criterion and a coordinated control method for active front steering (AFS) and direct yaw moment control (DYC) are proposed. First, the intervention criterion of AFS/DYC stability control based on the working state of lateral tyre force is proposed. Next, a 7-DOF (degree-of-freedom) dynamics model is established, and a method for identifying nonlinear pure lateral force model based on onboard sensors and vehicle handling stability experiment is developed. Then, the mapping relationship between lateral tyre force saturation point and wheel angle is constructed to rapidly judge the working state of lateral tire force. Subsequently, a UKF-based state observer, a hierarchical control algorithm and the yaw moment distribution coefficient are designed for the proposed AFS/DYC control system. Finally, a fishhook test and a step input test are carried out on low adhesion coefficient roads to verify the effectiveness of the proposed AFS/DYC coordinated control method.

Vehicle direct yaw moment control system based on the improved linear quadratic regulator

Purpose This study aims to propose an improved linear quadratic regulator (LQR) based on the adjusting weight coefficient, which is used to improve the performance of the vehicle direct yaw moment control (DYC) system. Design/methodology/approach After analyzing the responses of the side-slip angle and the yaw rate of the vehicle when driving under different road adhesion coefficients, the genetic algorithm and fuzzy logic theory were applied to design the parameter regulator for an improved LQR. This parameter regulator works according to the changes in the road adhesion coefficient between the tires and the road. Hardware-in-the-loop (HiL) tests with double-lane changes under low and high road surface adhesion coefficients were carried out. Findings The HiL test results demonstrate the proposed controllers’ effectiveness and reasonableness and satisfy the real-time requirement. The effectiveness of the proposed controller was also proven using the vehicle-handling stability objective evaluation method. Originality/value The objective evaluation results reveal better performance using the improved LQR DYC controller than a front wheel steering vehicle, especially in reducing driver fatigue, improving vehicle-handling stability and enhancing driving safety.

Optimal Coordinated Control of ARS and DYC for Four-Wheel Steer and In-Wheel Motor Driven Electric Vehicle With Unknown Tire Model

To improve the handling and maneuverability of four-wheel steer (4WS) and in-wheel motor driven electric vehicle (EV) in which the mechanical properties of tires are unknown, an optimal coordinated control combining active rear wheel steering (ARS) and direct yaw moment control (DYC) in the form of active drive torque distribution is proposed. By designing a new type of particle filter (PF), the online identification of unknown tire model is realized and its uncertainties and road surface disturbances are both considered. The constraints of vehicle motions tracking ideal values are derived according to the estimated tire lateral forces with Lyapunov stability theory. And then based on the thought of backstepping and optimization, the drive torque distribution method and the rear wheel steer strategy are obtained aiming at minimizing tire load and control inputs, which also take the effective working range of in-wheel motor into account. Finally, the validity and practicability of overall controller are verified through the simulation of Carsim and Matlab/Simulink. The proposed control strategy lays a theoretical foundation for the integration and optimization of 4WS EVs driven by in-wheel motors.

LPV/H∞ Controller Design for Path Tracking of Autonomous Ground Vehicles Through Four-Wheel Steering and Direct Yaw-Moment Control

This paper focuses on the path-tracking controller design for autonomous ground vehicles (AGVs) using four-wheel steering (4WS) and direct yaw-moment control (DYC) systems. In order to deal with the parametric uncertainties, a linear parameter-varying (LPV) H∞ controller is designed as the high-level controller to generate the front and rear wheel steering angles and external yaw moment based on linear matrix inequality (LMI) approach. The lower-level controller is designed for torque allocation between the left and right side wheels to yield the desired total longitudinal force and external yaw moment utilizing weighted least square (WLS) allocation algorithm. To test the performance of the proposed path-tracking controller, numerical simulations are carried out based on a high-fidelity and full-vehicle model constructed in CarSim. Simulation results show that the LPV/H∞ controller has better path-tracking performance than the fixed gain H∞ controller. To show the superiority of 4WS+DYC control system, the contrast simulation is performed based on LPV/H∞ controller. Simulation results indicate that 4WS+DYC control system has better path-tracking performance and handling stability than active front steering (AFS), AFS+DYC and 4WS control systems.

Integrated control of AFS and DYC for in-wheel-motor electric vehicles based on operation region division

The integrated chassis control system can improve vehicle handling and stability effectively. This paper proposes an integrated control system based on operation region division of active front steering (AFS) and direct yaw moment control (DYC) for in-wheel-motor electric vehicles. The control system adopts a two-layer hierarchical control structure. The decision layer employs a modified sliding mode controller to calculate the required corrective yaw moment, and determines operating regions of the two subsystems based on the driving conditions (road adhesion coefficient, tyre load and wheel slip ratio). The execution layer generates the corrective steer angle and the driving/braking torques for the AFS and DYC subsystems respectively. Simulation results show that on the high-adhesion-coefficient road, the integrated control system appropriately adopts subsystems to improve handling, while attenuating the workload of barking system; on the slippery road, the integrated control system maintains vehicle stability and provides control performance superior to those resulting from the single systems.

Integrated control performance of drive-by-wire independent drive electric vehicle

In order to improve the stability and safety of vehicles, it is necessary to control them. In this study, the integrated control method of drive-by-wire independent drive electric vehicle was studied. Firstly, the reference model of electric vehicle was established. Then, an integrated control method of acceleration slip regulation (ARS) and direct yaw moment control (DYC) was designed for controlling the nonlinearity of tyre, and the simulation experiment was carried out under the environment of MATLAB/SIMULINK. The results showed that the vehicle lost its stability when it was uncontrolled; under the control of a single DYC controller, r and β values got some control, but the vehicle stability was still low; under the integrated control of ARS+DYC, the vehicle stability was significantly improved; under the integrated control method, the overshoot, regulation time and steady-state error of the system were all small. Under the simulation of extreme conditions, the integrated control method also showed excellent performance, which suggested the method was reliable. The experimental results suggests the effectiveness of the integrated control method, which makes some contributions to the further research of the integrated control of electric vehicles.

Reliable Integrated ASC and DYC Control of All-Wheel-Independent-Drive Electric Vehicles Over CAN Using a Co-Design Methodology

This paper deals with the negative effects of the in-vehicle network on the integrated anti-slip control (ASC) and direct yaw-moment control (DYC) of all-wheel-independent-drive electric vehicles (AWID-EVs). In the integrated control design of the modern AWID-EVs, increasing control components, e.g., sensors, controllers, and actuators, are usually connected via an in-vehicle network, such as a controller area network (CAN), rather than the traditional point-to-point communication. However, the application of CAN would also bring about unexpected problems, e.g., signal asynchrony, multiple-package transmission, and signal delay, which may degrade the control performance and even destroy the stability of the system. This paper presents a co-design methodology to deal with all these challenges caused by CAN and guarantees a satisfactory vehicle dynamics performance. First, a hierarchical structure is designed for the integrated ASC and DYC control of AWID-EVs over CAN, and an active torque distribution strategy based on a well-known maximum transmissible torque estimation approach is adopted. Then, a scheduling-based communication idea is introduced to deal with all these problems caused by CAN. Third, a Lyapunov-based pole assignment theory is applied to estimate the parameter values in the scheduling design and to guarantee the satisfactory dynamic performance of the control system. A generalized linear quadratic regulator controller is designed for the system synthesis to ensure the tracking control of the vehicle. Finally, simulations and preliminary hardware-in-loop tests indicate that the proposed co-design methodology can deal with the negative effects of the in-vehicle network and ensure reliable vehicle dynamics performance.

The Decoupling Control of ARS and DYC Based on the Neutral Network Inverse System Method

According to the interference and coupling characteristics among sub-systems of the chassis of the forklift truck, the the neutral network inverse system method of the non-linear system is applied for the decoupling control of the active rear steering (ARS) and the direct yaw moment control (DYC) of the forklift truck. Based on the analysis of the reversibility of the chassis system, a back propagation neutral network reverse system model is set to decouple the chassis system into two independent pseudo-linear system; A PD closed loop controller is designed to comprise a composite controller with the neutral network reverse system and the simulation is performed for verification. The simulation result shows that the decoupling control strategy with the neutral network reverse system can eliminate the interference and coupling among sub-systems of the chassis and thus enhances the status tracking and operating stability of forklift trucks.

Study on Integrated Control of AFS and DYC for Active Obstacle Avoidance

In order to realize the obstacle avoidance and improve the vehicle’s yaw stability, a chassis integrated controller which cooperated Active Front Steering (AFS) and Direct Yaw Moment Control (DYC) is designed based on model predictive control (MPC) theory. It takes the corrective steering angle and desired yaw moment as inputs, and composes the driver-vehicle-road closed-loop system with the driver model. Performance of the controller is demonstrated as the continuous obstacle avoidance case. The simulation results show that the integrated controller can make the vehicle avoid the obstacle on both sides of the road and improve the yaw stability of the vehicle.

Vehicle handling and stability control by the cooperative control of 4WS and DYC

This paper proposes an integrated control system that cooperates with the four-wheel steering (4WS) and direct yaw moment control (DYC) to improve the vehicle handling and stability. The design works of the four-wheel steering and DYC control are based on sliding mode control. The integration control system produces the suitable 4WS angle and corrective yaw moment so that the vehicle tracks the desired yaw rate and sideslip angle. Considering the change of the vehicle longitudinal velocity that means the comfort of driving conditions, both the driving torque and braking torque are used to generate the corrective yaw moment. Simulation results show the effectiveness of the proposed control algorithm.

Integrated control of direct yaw moment control and active suspension system for 4wd vehicles

This paper presents an integrated control of DYC (direct yaw moment control system) and ASS (active suspension system) for 4WD (four-wheel drive) vehicles. In order to improve the comprehensive performance of 4WD vehicles, a ten degree of freedom nonlinear vehicle dynamics model is established and the torque distribution characteristic of an inter-wheel torque distribution device is analyzed. Based on the two degree of freedom linear vehicle model, the direct yaw moment controller with distribution of driving force is designed by means of sliding mode variable structure control. The active suspension system controller with a double-loop control structure is designed on the basis of its dynamics model. According to the analysis of the influence of the suspension on the vehicle steering performance, the integrated control of direct yaw moment control system and active suspension system is studied. The simulation of step steering condition and single lane change condition of vehicle is carried out using MATLAB/Simulink software. The simulation results show that the integrated control system can obviously improve vehicle riding comfort and handling stability much more than the individual control.DOI: http://dx.doi.org/10.5755/j01.mech.23.3.18481

Lateral handling improvement with dynamic curvature control for an independent rear wheel drive EV

The integrated longitudinal and lateral dynamic motion control is important for four wheel independent drive (4WID) electric vehicles. Under critical driving conditions, direct yaw moment control (DYC) has been proved as effective for vehicle handling stability and maneuverability by implementing optimized torque distribution of each wheel, especially with independent wheel drive electric vehicles. The intended vehicle path upon driver steering input is heavily depending on the instantaneous vehicle speed, body side slip and yaw rate of a vehicle, which can directly affect the steering effort of driver. In this paper, we propose a dynamic curvature controller (DCC) by applying a the dynamic curvature of the path, derived from vehicle dynamic state variables; yaw rate, side slip angle, and speed of a vehicle. The proposed controller, combined with DYC and wheel longitudinal slip control, is to utilize the dynamic curvature as a target control parameter for a feedback, avoiding estimating the vehicle side-slip angle. The effectiveness of the proposed controller, in view of stability and improved handling, has been validated with numerical simulations and a series of experiments during cornering engaging a disturbance torque driven by two rear independent in-wheel motors of a 4WD micro electric vehicle.

Lateral Handling Improvement with Dynamic Curvature Control for an Independent Rear Wheel Drive EV

The integrated longitudinal and lateral dynamic motion control is important for four wheel independent drive (4WID) electric vehicles. Under critical driving conditions, direct yaw moment control (DYC) has been proved as effective for vehicle handling stability and maneuverability by implementing optimized torque distribution of each wheel, especially with independent wheel drive electric vehicles. The intended vehicle path upon driver steering input is heavily depending on the instantaneous vehicle speed, body side slip and yaw rate of a vehicle, which can directly affect the steering effort of driver. In this paper, we propose a dynamic curvature controller (DCC) by applying a newly-defined parameter, the dynamic curvature of the path, derived from vehicle dynamic state variables; yaw rate, side slip angle, and speed of a vehicle. The proposed controller, combined with DYC and wheel longitudinal slip control, is to utilize the dynamic curvature as a target control parameter for a feedback, avoiding estimating the vehicle side-slip angle. The effectiveness of the proposed controller, in view of stability and improved handling, has been validated with numerical simulations and a series of experiments during cornering engaging a disturbance torque driven by two rear independent in-wheel motors of a 4WD micro electric vehicle.

Integrated Control of Nonlinear Vehicle Stability

A novel vehicle stability control method integrated direct yaw moment control (DYC) with active front steering (AFS) is presented in this paper. By the phase plane of sideslip angle and sideslip angular velocity, vehicle stable region is determined. When the vehicle is outside the stable region, DYC controller is firstly used to produce proper direct yaw moment, which can make the vehicle back to the stable region. Then AFS controller of sliding mode variable structure is constructed and used to control the front steering angle of the actual vehicle, so that the sideslip angle and yaw rate of the actual vehicle model can track those of the reference vehicle model. Computer simulations are carried out on a 2-DOF nonlinear vehicle model to investigate the effectiveness of the proposed method. And the simulation results show that the influence of the proposed method on enhancing vehicle stability is significant. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2609

Direct Yaw-Moment Control through Optimal Control Allocation Method for Light Vehicle

This paper presents a Direct Yaw-moment Control (DYC) strategy to prevent light vehicles from entering the unsteady state and improve the handling stability. A novelty of this work is the ability to achieve superior performance through the lower workload of the actuators by using the optimal control allocation method to distribute the active yaw moment. In the main-loop, the DYC controller is designed based on the classical PID algorithm with the yaw rate and sideslip angle feedback. Simulation tests are carried out on the conditions of sine steering and single lane change steering. Results indicate that the working potential of each actuator can be fully utilized and a significant improvement in handling stability can be achieved from the DYC system.