Rollover Dynamics Research Articles

Dynamics performance of long combination vehicles with active control systems

A state-of-the-art review of the dynamics of long combination vehicles (LCVs) is provided. The performance-based standards (PBS) that are commonly used globally are reviewed, including those in Canada and Australia. The discussions include the low-speed and high-speed longitudinal, lateral, and yaw performance of LCVs, which in many respects are different than the conventional tractor-semitrailers. The low-speed discussions include the vehicle startability, gradeability, acceleration, and offtracking. The high-speed considerations include rollover dynamics, braking distance and time, overtaking, down-grade holding, and ride quality. Some of the latest development in actively controlled (intelligent) systems to improve LCVs’ dynamic performance is emphasised, such as hill-start assist (HAS), roll stability control (RSC), electronic stability control (ESC), electrified dolly (e-dolly), active trailer steering (ATS), active braking, slip control (SC), active trailer differential braking (ATDB), active and semi-active antiroll bars, and active and semi-active suspensions. The study concludes that although great progress has been made during the past two decades for integrating advanced, intelligent, electromechanical systems in LCVs, much more work remains to address some of the future environmental and performance demands, particularly considering the integration of electrical and alternative-fuel propulsion systems in heavy commercial vehicles.

Using a novel fuzzy 3-inputs algorithms to control the active hydraulic stabilizer bar with the complex model of the vehicle nonlinear dynamics.

Under the influence of centrifugal force, the rollover phenomenon may occur. The vehicle rolls over when the wheel is completely separated from the road surface, i.e., the vertical force of the wheel is reduced to zero. To overcome this problem, the active stabilizer bar is used at the front and rear axles of the vehicle. The active stabilizer bar works on the difference in fluid pressure inside the hydraulic motor. This article is aimed at studying the vehicle rollover dynamics when the hydraulic stabilizer bar is used. In this article, the model of a complex dynamic is established. This is a combination of the model of spatial dynamics, the model of nonlinear double-track dynamics, and the nonlinear tire model. The operation of the hydraulic actuator is controlled by a fuzzy algorithm with 3-inputs. The defuzzification rule is determined based on the combination of 27 cases. The process of calculation and simulation is done with four specific cases corresponding to steering angles. In each case, three situations were investigated. Besides, the speed of the vehicle is also gradually increased from v1 to v4. As a result of the simulation, which was performed in the MATLAB-Simulink environment, the output values such as roll angle, change of the vertical force, and roll index were significantly reduced when the active stabilizer bar was used. If the vehicle does not use the stabilizer bar, the vehicle may roll over in both the second, third, and fourth cases. If the vehicle uses a mechanical stabilizer bar, this also occurs in the third and fourth cases (only at a very high velocity, v4). However, the rollover phenomenon did not occur if the vehicle used a hydraulic stabilizer bar controlled by the fuzzy 3-inputs algorithm. In all investigated cases, the stability and safety of the vehicle are always guaranteed. Besides, the responsiveness of the controller is also very good. An experimental process needs to be conducted to verify the correctness of this research.

The Effect of Steering Effort on the Simulated Rollover Dynamics Behavior of Cars

The Effect of Steering Effort on the Simulated Rollover Dynamics Behavior of Cars

Warning and active steering rollover prevention control for agricultural wheeled tractor.

Tractor rollover is regarded as the most fatal incident in agricultural production, but some of which can be avoided by timely anti-rollover warning and active control. There have been a lot of researches on the tractor rollover model building and rollover protective structure designing but few on the anti-rollover control. The purpose of this study is to develop a cheaper and practical anti-rollover control system based on active steering technique and to prove the efficiency of the proposed scheme for the wheeled tractors. A three-degree-of-freedom rollover dynamics model including automatic steering system is established. A control scheme by adjusting the roll angle to keep the stability based on the adaptive sliding mode control is proposed with the estimated lateral velocity according to the feedback correction principle. Front wheel angle tracking controller is designed adopting internal model control (IMC) theory. Simulation results exhibit that the active anti-rollover control can calculate the stability index in real time and can keep it within the stable range by adjusting the front steering wheel angle. It is prospective for the proposed scheme to provide a valuable reference to reduce tractor rollover accidents.

Design of a rollover index-based sliding mode controller for roll stability of three wheeled vehicles using rear differential braking

Urban vehicles (like tricycle and bicycle vehicle) are made to handle issues with traffic, air pollution, energy use, and parking restrictions in big cities. However, they are more susceptible to rollovers and stability problems because they are smaller and narrower than normal cars. Now a day, Vehicle manufacturers place a lot of emphasis on the dynamic stability of their products. As a result, develop dynamic model to predict and detect the risk of rollover and designing a controller to reduce it in a delta type configuration of tricycle vehicle is the major concern of this paper. On the basis of a two degree of freedom (2-DOF) bicycle model, develop rollover dynamics, and design state observer for sideslip angle, sliding mode and fuzzy logic controller are the major concern of this paper. The suggested rollover index (RI) accuracy has been evaluated by simulation using a high-fidelity CarSim. The performance analysis to determine the effectiveness of thus proposed controller is conducted using MATLAB/Simulink integrated with the Carsim software. Simulation results with three scenarios are shown with and without the control system. The outcome of the simulation demonstrated that fuzzy sliding mode controller (FSMC) and a fuzzy logic controller can reduces the chance of a vehicle rolling over accident.

A complex rollover dynamics model with active stabilizer bar controlled by the fuzzy algorithm

The active stabilizer bar is used to improve the vehicle's safety when steering at high speeds. In this paper, the spatial dynamics model and nonlinear double-track dynamics model are used to simulate vehicle oscillations. Besides, the nonlinear tire model is also used. This is a completely novel and complex model. Besides, the fuzzy control algorithm is used to control the active stabilizer bar. This algorithm uses two input signals, which are obtained from the simulation. The membership function and fuzzy rules are designed optimally based on the results of many previous simulations and calculations. The simulation process is performed by MATLAB-Simulink software with three specific cases. The results of the paper show that the roll angle of the vehicle body and the change in vertical force at the wheel are significantly reduced when the vehicle uses the active stabilizer bar controlled by the fuzzy algorithm. The rollover phenomenon has been significantly improved in all the investigated cases, corresponding to three specific speeds. The stability and responsiveness of the controller are very high. The fuzzy algorithm can be combined with some other algorithms to improve system efficiency.

Research on Vehicle Rollover Warning and Braking Control System Based on Secondary Predictive Zero-Moment Point Position

<div class="section abstract"><div class="htmlview paragraph">To solve the contradiction between model complexity and the warning accuracy of the algorithm of the vehicle rollover warning, a rollover state warning method based on the secondary predictive zero-moment point position for vehicles is proposed herein. Taking a sport utility vehicle(SUV) as the research object, a linear three-degrees-of-freedom vehicle rollover dynamics model is established. On the basis of the model, the lateral position of the zero-moment point and its primary and secondary rates of change are calculated. Then, the theoretical solution of time-to-rollover of the vehicles is deduced from the lateral position of the secondary predictive zero-moment point. When the rollover warning index, the lateral position of the zero-moment point, is greater than the set threshold, the active anti-rollover control system will be triggered. The active anti-rollover braking control system adopts a hierarchical control strategy. Taking the rollover warning index as the control target, the upper controller calculates the braking torque required by the front-outer wheel based on the Fuzzy Proportional Integral Derivative (PID) algorithm and the differential braking control strategy. The lower executive controller calculates the corresponding brake wheel cylinder pressure and inputs it to the corresponding wheel through the Electrical Hydraulic Brake(EHB), so that a certain additional yaw moment can be formed to prevent the vehicle from rolling over. Under some typical driving conditions, Carsim-Matlab co-simulation and real vehicle tests are carried out. The comparative test results show that the proposed rollover warning method based on the secondary predictive zero-moment point position can accurately and effectively predict the roll-over state of the vehicle, and the active anti-rollover braking control system can control the vehicle in time and effectively to prevent the vehicle from rollover.</div></div>

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.

Rollover dynamics modelling and analysis of self-propelled combine harvester

This study investigated the rollover phenomenon of a self-propelled combine harvester during short-distance cross-region travel on a road. The mathematical model of the unsteady lateral multi-degree-of-freedom (multi-DOF) motion of the combine harvester was established with consideration to rear wheel steering, front wheel braking, wheel sideslip, and tyre lateral deflection. By carrying out complex kinematics analysis for the entire vehicle and rotational dynamics analysis for the wheels, the mathematical relationships among the lateral deflection angles of the tyres, the kinematic parameters of the combine harvester centroid, the steering angles of the rear wheels, and the speed components of the wheel centroids along their longitudinal directions were derived and used to transform the established mathematical model into a novel form that considers the steering angles and kinematic parameters as unknown quantities. The lateral load transfer ratio (LTR) model of the combine harvester was established to assess the harvester's rollover critical state. Finally, by considering the steering angles of the rear wheels and the braking torque of the front wheels as model inputs, the rollover mechanism and effects of the structural geometry, steering angles, and braking torque on the LTR of the combine harvester were revealed through numerical calculation, and the safety intervals of the parameters were obtained. The results obtained by this study can provide theoretical and technical support for the dynamic design, control, and rollover protection of combine harvesters. • The rear-wheel steering instability analysis method of a combine is proposed. • An unsteady lateral motion model of the combine is established. • Mathematical relationships among the multiple kinematic parameters are established. • The parameter effects and rollover mechanism of the combine are revealed. • Results give a theoretical basis to the anti-rollover design, control and warning.

Rollover detection and prevention of a heavy-duty vehicle on banked and graded uneven road

The roll performance of vehicle with flexible frame and solid axle suspension has been less studied in current researches. To reveal rollover mechanism of vehicle with flexible frame and solid axle suspension on banked and graded uneven road, a novel rollover index and an integrated control strategy for vehicle rollover are proposed. Taking the coupling of roll motion of sprung mass of the front axle with that of the drive axle into consideration, 10 DOF dynamic model is established. Then, a novel rollover index is derived from rollover dynamics. Moreover, an integrated control strategy combining active steering and active braking of the rear wheel is developed and optimised offline by genetic algorithm. Finally, some numerical cases are studied under untripped and complicated tripped rollover conditions. Results state that the integrated control strategy has good robustness, which can prevent the heavy-duty vehicle rollover effectively and keep the drive intention simultaneously.

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.

Study on Rollover Index and Stability for a Triaxle Bus

Vehicle rollover, and its resulting fatalities, is an actively researched topic especially for multi-axle vehicles in the field of vehicle dynamics and control. This paper first presents a new rollover index for a triaxle bus to accurately evaluate its rollover possibility and then discusses the influence laws of the vehicle rollover dynamics to explore the mechanism of its stability. First, a six degree of freedom rollover model of the triaxle bus is developed, including lateral, yaw, roll motion of the sprung mass of the front/rear axle, and roll motion of the unsprung mass of the front/rear axle. Next, some key parameters of the vehicle rollover model are identified. A new rollover index is deduced according to the basics of vehicle dynamics, to predict vehicle rollover risk for the triaxle bus, which is verified by TruckSim. Furthermore, the influence laws of vehicle rollover dynamics by vehicle parameters and road parameters are discussed based on the simulation results. More importantly, the results show that the new method of modeling can precisely describe the rollover dynamics of the studied bus, and the proposed new index can effectively evaluate the rollover possibility. Therefore, this study provides a theoretical basis to improve anti-rollover ability for triaxle buses.

Rollover prevention for a heavy vehicle using optimised slide mode steering control

For a heavy vehicle, active steering can effectively prevent rollover, however, it also changes the operation of the vehicle away from the driver's intentions. To improve rollover stability and reduce tracking error, an optimised slide mode steering control strategy is proposed. Four degrees of freedom linear model is used, which includes lateral, yaw, and roll motions of the sprung mass and unsprung mass. This model is also validated to describe heavy vehicle rollover dynamics. From the model, slide mode control based roll angle and lateral displacement strategies are developed, respectively, and the optimised slide mode steering control strategy is presented to track the set routes and prevent vehicle rollover. Furthermore, some typical numerical cases are simulated to demonstrate the effectiveness of the control strategies. The results show that the optimised strategy can effectively prevent vehicle rollover and significantly improve the performance of tracking the driver's intention for a heavy vehicle.

LQR Anti-rollover Control of Active Suspension in Vehicle

In order to improve the ability of anti-rollover for vehicle, the paper established a 4 DOF vehicle rollover dynamics model, and proposed a LQR control strategy based on active suspensions for vehicle. Under the Matlab/Simulink, the simulations and the results show that the presented control scheme not only can reduce the roll angle and roll angular velocity, but also can improve the rollover stability of the vehicle, and reduce the possibility of vehicle rollover accident.

State Estimation of Vehicle’s Dynamic Stability Based on the Nonlinear Kalman Filter

An accurate estimation of a vehicle’s state of motion is the basis of dynamic stability control. Two different nonlinear Kalman filters are adopted for the estimation of the vehicle’s lateral/rollover stability state. First, the overall structure of the state estimation with four inputs and four outputs is introduced. After determining tire-cornering stiffness using a recursive least-squares (RLS) method, the equations of state and of observation for the nonlinear Kalman filter are established based on a vehicle model with four degrees of freedom including planar and rollover dynamics. Then, the specific steps of real-time state estimation using the extended Kalman filter (EKF) and unscented Kalman filter (UKF) are both given. In a co-simulation, we find that the RLS algorithm estimates tire-cornering stiffness accurately and quickly, and the UKF improves the effect of state estimation compared with EKF. In addition, the UKF is verified against data from vehicle tests. The results show the proposed method is reliable and practical in estimating vehicle states.

Advanced design for vibroseis truck's ROPS and its secure and protective performance analyses based on dynamics simulation research

This research develops a design methodology for the vibroseis truck rollover protective structure (ROPS) and analyses its safety and protective performance with dynamics simulations. A new ROPS with the vertical anti-rolling over property is designed. For the typical field working conditions, we perform the stability study on the vibroseis truck and find its threshold function by using rollover dynamics. With the proposed protection and performance evaluation criteria, we analyse the protection performance of the new and old ROPS with finite element (FE) dynamics simulation. Then, the stress to strain, impact deformation, impact acceleration and interior energy distribution law are obtained during the process of the truck rolling over. The effect of the structure on its protective performance is also found. These analyses result in an optimal design of ROPS. The results will improve the safety of vibroseis trucks and then enhance the technology of oil and gas exploration equipment.

Rollover Dynamics of a Narrow Tilting Three-Wheeled Vehicle

A narrow-track vehicle possesses many advantages like fuel efficiency and reduced road footprint among others. But the main drawback of this model stems from the fact that they tend to rollover more easily due to their narrow base area. In order to overcome this rollover instability, these vehicles are made to tilt to obtain increased virtual base area. The focus of this paper is to analyse the minimum lean angle necessary for a narrow three-wheeled vehicle under lateral acceleration to negotiate a curve safely. In addition, the influence of the horizontal positions of the centre of mass of the vehicle over the rollover speeds is studied.

ATV Rollover, Rider Response, and Determinants of Injury: In-depth Analysis of Video-documented ATV Rollover Events

Objective: All-terrain vehicle (ATV) rollover events can lead to serious and fatal injuries. Crush protection devices (CPDs) are intended to reduce injury by reducing the frequency of significant contact between an inverted ATV and rider. Currently, field data on real-world ATV rollovers are primarily limited to injury causing events and lack ATV and rider dynamics necessary to evaluate injury mitigation effectiveness and possible unintended consequences of CPDs. Unlike restrained automobile occupants, ATV rider posture and positioning are highly variable and scant data are available to define the dynamically changing rider position in a roll scenario. Additional data on the complex real-world dynamics and interactions of riders and vehicles are needed to further develop and evaluate the effectiveness of rollover injury prevention strategies.Methods: Using YouTube videos of real-world rollover events, vehicle, environment, and rider factors were categorized with a focus on vehicle dynamics and rider responses, including dismount kinematics.Results: One hundred twenty-nine ATV rollover events were coded, with side rolls representing 47%, rear 44%, and forward rolls 9%. The speed at onset of roll was relatively low, with 86% of the rolls occurring at speeds of 10 mph or less and 53% occurring at less than 3 mph. No injury was identified for 79% of the events; 16% resulted in injury due to ATV contact and 5% resulted in injury unrelated to ATV contact. Active dismount of the ATV was a commonly employed strategy, with 63% of the riders attempting active dismount, resulting in successful separation from the ATV in 72% of the attempts. The overall injury rate for riders attempting active dismount was 15% and the injury rate for riders not attempting active dismount was 32%. This investigation confirmed the importance of active rider movements, including active dismount and subsequent separation in determining the outcome of ATV roll events.Conclusions: Rider active dynamics need to be considered when introducing new injury prevention strategies that may obstruct, impede, or otherwise contact riders during an attempted separation. To the authors’ knowledge, this is the first systematic use of real-world video-documented ATV rollover events to quantify and analyze ATV rollover dynamics and rider responses. These data and techniques can guide effective design and implementation of injury mitigation strategies.

Investigations on Vehicle Rollover Prevention Using Dead-Beat Controller

This paper presents results of an initial investigation into models and control strategies suitable to predict and prevent vehicle rollover due to untripped driving maneuvers. Outside of industry, the study of vehicle rollover inclusive of experimental validation, model-based predictive algorithms, and practical controller design is limited. The researcher interested in initiating study on rollover dynamics and control is left with the challenging task of identifying suitable vehicle models from the literature, comparing these models in their ability to match experimental results, and determining suitable parameters for the models and controller gains. For vehicles that are deemed to be susceptible to wheel-lift, various open-loop control strategies are implemented in simulation. The primary assumption in their implementation is that the vehicle in question is equipped with a steer-by-wire system. Nomenclature

Analysis of vehicle rollover dynamics using a high-fidelity model

Recent data show that 35% of fatal crashes in sport utility vehicles included vehicle rollover. At the same time, experimental testing to improve safety is expensive and dangerous. Therefore, multi-body simulation is used in this research to improve the understanding of rollover dynamics. The majority of previous work uses low-fidelity models. Here, a complex and highly nonlinear multi-body model with 165 degrees of freedom is correlated to vehicle kinematic and compliance (K&C) measurements. The Magic Formula tyre model is employed. Design of experiment methodology is used to identify tyre properties affecting vehicle rollover. A novel, statistical approach is used to link suspension K&C characteristics with rollover propensity. Research so far reveals that the tyre properties that have the greatest influence on vehicle rollover are friction coefficient, friction variation with load, camber stiffness and tyre vertical stiffness. Key K&C characteristics affecting rollover propensity are front and rear suspension rate, front roll stiffness, front camber gain, front and rear camber compliance and rear jacking force.