Vehicle Rollover Stability Research Articles

Analysing the Effect of Chassis Torsional Flexibility on the Rollover Threshold of a Multi-Purpose Agricultural Vehicle

Multi-purpose agricultural tractors are vehicles that are usually involved in different operations, including road maintenance in small villages and cultivation of small agricultural plots, particularly in mountainous areas. These vehicles typically feature narrow tracks to enhance manoeuvrability, making rollover stability a critical consideration in operational settings. This characteristic arises from the interplay between the suspension and vehicle chassis. This paper introduces a numerical multi-body model designed to replicate the dynamics of a multi-purpose tractor with a torsional chassis. Model parameters were derived through experimental measurements conducted on an actual vehicle. Static measurements were performed to assess tire and suspension stiffness while tilting tests were performed to establish the static rollover limit of the vehicle. Dynamic tests conducted on a four-post test rig characterised the vehicle’s dynamics. The validated model was utilised to explore the vehicle’s stability by reproducing the static rollover tests and simulating the vehicle’s performance under working conditions on a banked road. The vehicle rollover stability was studied by performing a sensitivity analysis that considered both chassis torsional stiffness and suspension stiffness under different loading conditions. The results indicate a trade-off between frame and suspension stiffnesses that enhances overall vehicle stability.

Model predictive control for three-axle trucks during tire blowout on expressway based on equivalent chassis

Unexpected tire blowout on expressway is one of the most dangerous scenarios for heavy load multi-axle trucks, especially under the inexperienced driver’s improper intervention. To this end, this paper proposes an autonomous tire blowout controller for three-axle trucks based on model predictive control (MPC) method. First of all, aiming at balancing the computing load and the path-tracking accuracy, an equivalent chassis is transformed based on the stable two-dimensional vehicle dynamic model. Second, a tire blowout–oriented vehicle high-fidelity dynamic model is established based on the equivalent chassis, in which the vehicle lateral, yaw, and roll motions are all considered at the same time. Then, an MPC-based dynamic control strategy is proposed to achieve effective tire blowout suppression with the consideration of vehicle rollover stability. Afterward, a transient vertical tire force shock is employed to simulate the real tire blowout behavior, on which two typical scenarios are constructed based on the TruckSim–Simulink co-simulation platform. The simulation results illustrate the feasibility and effectiveness of the proposed method. In two different dangerous tire blowout conditions, the lateral load transfer rate (LTR) value of the vehicle is reduced by 3.45% and 40.87%, respectively, while the trajectory tracking error is reduced at the same time.

Study on Highway Alignment Optimization Considering Rollover Stability Based on Two-Dimensional Point Collision Dynamics

In order to reduce the influence of unreasonable road alignment design on vehicle driving safety, a study on road alignment optimization and vehicle driving safety based on two-dimensional point collision dynamics was carried out. First, through the two-dimensional point collision dynamics model, the relationship of the kinematic parameters before and after vehicle collision was deduced. Second, according to the vehicle–road coupling dynamic model analysis after collision, the safety threshold between the radius of the circular curve and the road superelevation was derived by taking vehicle rollover as the critical condition. Next, the road alignment optimization scheme based on vehicle rollover stability after collision was proposed. Finally, the rationality of the optimization scheme was verified by PC-Crash simulation. The simulation results showed that the proposed optimization scheme of the minimum radius and superelevation of the circular curve meets the safety requirements of vehicle rollover. This study optimized the relevant indicators of the road alignment under the premise of ensuring vehicle rollover stability and provides a reference for the improvement and optimization of road alignment design. It also has important guiding significance for the formulation of vehicle driving safety management measures.

Rollover Prevention and Motion Planning for an Intelligent Heavy Truck

It is very necessary for an intelligent heavy truck to have the ability to prevent rollover independently. However, it was rarely considered in intelligent vehicle motion planning. To improve rollover stability, a motion planning strategy with autonomous anti rollover ability for an intelligent heavy truck is put forward in this paper. Considering the influence of unsprung mass in the front axle and the rear axle and the body roll stiffness on vehicle rollover stability, a rollover dynamics model is built for the intelligent heavy truck. From the model, a novel rollover index is derived to evaluate vehicle rollover risk accurately, and a model predictive control algorithm is applicated to design the motion planning strategy for the intelligent heavy truck, which integrates the vehicle rollover stability, the artificial potential field for the obstacle avoidance, the path tracking and vehicle dynamics constrains. Then, the optimal path is obtained to meet the requirements that the intelligent heavy truck can avoid obstacles and drive stably without rollover. In addition, three typical scenarios are designed to numerically simulate the dynamic performance of the intelligent heavy truck. The results show that the proposed motion planning strategy can avoid collisions and improve vehicle rollover stability effectively even under the worst driving scenarios.

A mathematical model for determining and improving rollover stability of four-wheel earthmoving vehicles with arbitrary undercarriage system design

Earthmoving vehicles, especially ones with articulated frame steering, are very vulnerable to rollover. Consequently many dangerous rollover accidents occur all around the world. This problem is not only caused by difficult operating conditions and high productivity requirements. The current standards in this area do not offer an acceptable method of assessing vehicle rollover stability. Furthermore, in the previous literature there have been no research on rollover stability of increasingly common unconventional undercarriage systems, equipped with inclined/virtual oscillation and steering axes. In response to the above-mentioned situation, an innovative test vehicle, whose undercarriage system can be optionally selected (including unconventional solutions), was designed and built. The experimental stand consisted of a rotary-tilting platform equipped in wheel weighting pads and a two-axis inclinometer. Completely new experimental results were presented, proving a strong influence of unconventional undercarriage system on vehicle rollover stability. Moreover, the extensive experimental investigation was used to derive and validate an accurate and universal mathematical model, enabling to calculate and improve the rollover stability of any four-wheeled vehicle. It was also shown that a geometrical optimisation of an unconventional undercarriage system permits an increase in rollover stability—even up to several dozen percentage relative to the conventional solutions.

Control Strategy of Vehicle Anti-Rollover Considering Driver’s Characteristic

In the process of vehicle anti-rollover, the driver’s behavioral characteristics have a great influence on the vehicle rollover stability. However, the existing researches on anti-rollover rarely consider the driver in the human-vehicle-road closed loop system, which may directly affects the rollover dynamics characteristics of the vehicle. Aiming at this problem, this work analyzes the influence of different driver parameters on vehicle dynamics and establishes a driver model considering the vehicle rollover stability. Based on this, a collaborative control strategy of vehicle anti-rollover considering the driver’s characteristics is designed to assist the driving stability requirements of different types of drivers. It includes the upper layer of supervision decision control and the lower layer of cooperative execution control. The supervisory decision control layer sets different rollover constraint boundaries for different types of drivers, and makes six control decision modes combining driver input and vehicle path tracking error. Aiming at different types of drivers, the lower cooperative execution control layer constrains the front wheel angle by the active steering system to reduce yaw rate and the risk of rollover. Moreover, it reasonably distributes the braking force of four tires by the active braking system to reduce the path tracking error while preventing rollover. The simulation results show that, the proposed cooperative control strategy can provide different control effects for different drivers, and ensure the effective anti-rollover control of the vehicle and achieve good path tracking performance.

Integrated yaw and rollover stability control of an off-road vehicle with mechanical elastic wheel

An integrated control algorithm of the differential braking and the active suspension to improve yaw and rollover stability of vehicles with mechanical elastic wheel (ME-Wheel) is developed. By simplifying the structure of ME-Wheel, a fitting tire model named brush model is constructed. Then, a nonlinear 8-DOF vehicle model with ME-Wheel is built up for rollover prevention, which utilizes a predictive load transfer ratio (PLTR) as the rollover index and a Kalman filter is used to eliminate the measurement noise. In order to design an integrated control algorithm, fuzzy proportional-integral-derivative (PID) methodology is adopted by simultaneous control of the yaw and roll motions. The proposed algorithm, based on the idea that makes yaw stability controller and roll stability controller work independently first, then unifies by way of weight according to fuzz control, after that, brake force distributor selects single efficient braking wheel to achieve yaw moment and one of the front braking wheels with varying brake pressure to achieve the desired brake torque and the wheel slip regulator is designed with sliding mode control technique to prevent the wheels from locking; and the active suspension system alters the stiffness of the active suspension to prevent rollover. Simulation results show that the integrated yaw and rollover stability control system could improve the handing stability of vehicle under the limit driving conditions, and prevent rollover happening.

Influences of Driver on Vehicle Rollover Stability and Anti-roll Control

Influences of Driver on Vehicle Rollover Stability and Anti-roll Control

Vehicle roll-over stability in strong winds on long-span bridges

Vehicle roll-over stability in strong winds on long-span bridges

Study on the Rollover Characteristic of In-Wheel-Motor-Driven Electric Vehicles Considering Road and Electromagnetic Excitation

For in-wheel-motor-driven electric vehicles, the motor is installed in the wheel directly. Tyre runout and uneven load can cause magnet gap deformation in the motor, which will produce electromagnetic forces that further influence the vehicle rollover characteristics. To study the rollover characteristics, a verified 16-degree-of-freedom rollover dynamic model is introduced. Next, the vehicle rollover characteristics both with and without electromagnetic force are analyzed under conditions of the Fixed Timing Fishhook steering and grade B road excitation. The results show that the electromagnetic force has a certain effect on the load transfer and can reduce the antirollover performance of the vehicle. Therefore, the effect of the electromagnetic force on the rollover characteristic should be considered in the vehicle design. To this end, extensive analysis was conducted on the effect of the road level, vehicle speed, and the road adhesion coefficient on the vehicle rollover stability. The results indicate that vehicle rollover stability worsens when the above-mentioned factors increase, the most influential factor being the road adhesion coefficient followed by vehicle speed and road level. This paper can offer certain theory basis for the design of the in-wheel-motor-driven electric vehicles.

Anti-rollover Control System Design of Articulated Off-road Vehicles

This paper designs an anti-rollover control system to improve articulated off-road vehicle rollover safety. This controller consists two level control which target to two different instability stages: 1) the active swing bridge adjustment control algorithm for the first stage instability; and 2) the active braking control algorithm for the second stage instability. The first level control is based on fuzzy PID control and second is based on switch control, they work together to prevent the articulated wheel loader from rollover accident. Multi-body dynamics model of a ZL50 articulated wheel loader is built by commercial software RecurDyn, and the MBD model and controller model were co-simulated under the same solver in RecurDyn/CoLink. The co-simulation results show that, during the high speed steering rollover process, these two level controller work efficiently to reduce the roll angle and improve the vehicle rollover stability.

Consider Roll of Heavy Vehicle's Modeling Research

Existed consider roll of heavy vehicle's dynamics model have defects and deficiencies. Vehicles lateral-load transfer that will lead to vehicles rollover is not considered; the whole vehicles dynamics model neglect unspring masss roll angle while the unspring masss independent force analysis considered the roll angel, the establishment of the model is not consistent in; the model dont have a united positive direction rule for all the variables. Because of all of these defects the model cant rightly reflect vehicles motion status. This paper takes lateral-load transfer as a dynamic variable; unspring masss roll angle is considered when establishing the whole vehicles dynamics model; all variables positive direction is united. Reasonable, right, applied to evaluate vehicle's rollover stability and quite newly model is established.