Single Lane Change Test Research Articles

A Multi-Objective Optimal Torque Distribution Strategy for Four In-Wheel-Motor Drive Electric Vehicles

Since four in-wheel-motor drive electric vehicles (4IDEVs) are overactuated systems, the torque distribution strategy is crucial for improving the system efficiency, lateral stability, and safety. Hence, this paper proposes a multiobjective optimal torque distribution strategy for 4IDEVs to improve the vehicle yaw stability performance and energy efficiency. First, a motor energy loss model is built to describe the motor power loss characteristics, and an energy efficiency control allocation (EECA) method over the NEDC is proposed to analyze the model accuracy. Then, a hybrid model predictive control (hMPC)-based nonlinear yaw stability controller is employed to calculate the reference yaw moment and the active steering angle. Finally, a multiobjective controller is designed to minimize the drivetrain power loss while ensuring the vehicle stability, in which the four wheels torques are allocated to track the reference yaw moment. The proposed strategy is evaluated on the dSPACE-based platform over the single lane change test and fishhook steering test. The results indicate that the suggested torque distribution strategy can improve the vehicle stability on different conditions and the energy consumption is significantly reduced compared to an electric stability control (ESC) method.

Component Mode Modification Technique for Vibration Control

In the present paper, a vibration mode modification method when the dynamic characteristics of the vibration system change by assembly is proposed. When the dynamic characteristics change, component mode synthesis (CMS) is widely used. However, CMS is not suitable for vibration control. Therefore, the present paper proposes a component mode modification technique for vibration control problem. The vibration modes are modified using component modes for constructing a reduced-order model. In this method, vibration modes are modified using static correction modes (attachment modes). Using these modes, orthogonalization is performed by subspace iteration. First, the concept of vibration mode modification is proposed. This concept is then applied to the proposed modeling method, which is referred to as the extended reduced-order physical modeling method. Finally, the proposed method is examined through dynamic responses of an elastic vehicle. Using the elastic vehicle, a single lane change test and simulation are carried out.

Modelling Commercial Vehicle Handling and Rolling Stability

This paper presents a multi-degrees-of-freedom non-linear multibody dynamic model of a three-axle heavy commercial vehicle tractor unit, comprising a subchassis, front and rear leaf spring suspensions, steering system, and ten wheels/tyres, with a semi-trailer comprising two axles and eight wheels/tyres. The investigation is mainly concerned with the rollover stability of the articulated vehicle. The models incorporate all sources of compliance, stiffness, and damping, all with non-linear characteristics, and are constructed and simulated using automatic dynamic analysis of mechanical systems formulation. A constant radius turn test and a single lane change test (according to the ISO Standard) are simulated. The constant radius turn test shows the understeer behaviour of the vehicle, and the single lane change manoeuvre was conducted to show the transient behaviour of the vehicle. Non-stable roll and yaw behaviour of the vehicle is predicted at test speeds >90 km/h. Rollover stability of the vehicle is also investigated using a constant radius turn test with increasing speed. The articulated laden vehicle model predicted increased understeer behaviour, due to higher load acting on the wheels of the middle and rear axles of the tractor and the influence of the semi-trailer, as shown by the reduced yaw rate and the steering angle variation during the constant radius turn. The rollover test predicted a critical lateral acceleration value where complete rollover occurs. Unstable behaviour of the articulated vehicle is also predicted in the single lane change manoeuvre.

Vehicle dynamic analysis using virtual proving ground approach

Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, noise/vibration/harshness (NVH), crashworthiness and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, we used the virtual proving ground (VPG) approach for obtaining the dynamic characteristics. The VPG approach uses a nonlinear dynamic finite element code (LS-DYNA3D) which expands the application boundary outside the classic linear static assumptions. The VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic results, a single lane change test has been performed. The prediction results were compared with the experimental results, and the feasibility of the integrated CAE analysis methodology was verified.

Side-slip control to stabilize vehicle lateral motion by direct yaw moment

Following to the experimental validation of the side-slip estimation by model observer, the experimental study on the effects of the side-slip control by direct yaw moment on stabilizing vehicle motion which is impaired due to nonlinear tire characteristics is carried out. A double lane change test as well as a single lane change test with braking is conducted in order to prove the effect of the control on stabilizing the vehicle motion during severe maneuvering. It is proved that the side-slip control by DYC has a higher ability to stabilize the vehicle motion compared with 4WS because the vehicle losses its stability due to deterioration of rear tire characteristics, however, 4WS has to use the deteriorated rear tire to control the vehicle motion. The side-slip control is also proved to be superior to the yaw rate control to compensate for loss of stability due to nonlinear tire characteristics.