Anti-roll Research Articles

Analyses of the Effect of Clamping Distance on Stress and Roll Stiffness of Anti Roll Bar

Analyses of the Effect of Clamping Distance on Stress and Roll Stiffness of Anti Roll Bar

Prediction and evaluation of fatigue life for mechanical components considering anelasticity‐based load spectrum

AbstractTo accurately predict the degraded fatigue life of components under random loads, anelasticity effect of metal on life estimation needs to be explored. Weighting coefficient and dynamic elastic modulus are introduced to modify the calculation process of the model. By establishing an equal‐amplitude fatigue median surface and applying Miner linear fatigue cumulative damage theory, a fatigue life prediction model of the component under random loads is proposed. The model can be used to calculate the degraded fatigue life of components, which provides a theoretical basis for life estimation under random load spectrum. The two‐dimensional load spectrum is compared with the unprocessed two‐dimensional load spectrum and the one‐dimensional program spectrum in life prediction results. With the comparison of the target life and simulation life and the data calculated by the model of the automobile front stabilizer bar, it is concluded that the data obtained by the modified model are more reasonable and accurate.

Using an LQR active anti-roll bar system to improve road safety of tractor semi-trailers

Introduction: Tractor semi-trailer vehicles are playing an increasingly important role in the global freight chain. However, due to the heavy total load and height of the center of gravity, this type of vehicle is often at a higher risk of instability than other vehicles. This paper focuses on improving the vehicle roll stability by using an active anti-roll bar system.
 Methods: The Linear Quadratic Regulator (LQR) approach is used for this purpose with the control signal being the torque generated by the active anti-roll bar system. In order to synthesize the controller, the roll angle of the vehicle body and the normalized load transfer at all axles of the tractor semi-trailer vehicle are considered as the optimal goals.
 Results: The simulation results in time and frequency domains clearly show the effectiveness of the proposed method for the active anti-roll bar system, because the reduction of the desired criterias is about 40% less when compared to a vehicle using the passive anti-roll bar system.
 Conclusions: The effectiveness of the active anti-roll bar system on improving the vehicle roll stability, has been verified in this theoretical study with the LQR optimal controller. This is an important basis for conducting more in-depth studies and future experiments.

Material and design parameters optimization to enhance the life of Anti-Roll bar of commercial truck

In this study, an anti-roll bar that will be used in the front axle suspension of a 25 metric tonnes capacity rigid as well as construction Trucks s focused. It is redesigned to minimize the stress concentration at the corner bends. In order to execute this, regions that are under stress concentration during the roll motion of the vehicle body are determined by using finite element analysis. Geometric parameters which constitute the form of these regions are assigned. In the light of the results obtained from the stress analyses that were carried out for the different values of these parameters, stress and mass alteration are assessed by using Trial and Error Method. The effects of these modifications on stress concentration and anti-roll bar mass are studied. Response surfaces for maximum von Mises stress and the mass of the anti-roll bar are also constructed by Multi-body Dynamics and Hyper works commercial finite element software Package. By using these results, transition from among the design candidates that gives Minimum stress concentration is determined. Four kinds of modification in design considered which includes the change of material, radius of curvature and length of the bar. The dynamic analysis based results evaluated and suggested the outperformed design.

Developing a Strategy to Improve Handling Behaviors of a Medium-Size Electric Bus Using Active Anti-Roll Bar

Electric vehicles are a major trend in research and development in the automobile industry. A vehicle’s handling ability is changed when the structure of the power system is altered, which is more obvious in medium-sized buses with higher load and a longer body whose body stiffness is relatively less stiff. In this context, flexible multi-body dynamic modeling, instead of rigid body modeling, is used to reflect the stiffness effects of the vehicle body and chassis systems. A control strategy is developed with an active variable stiffness anti-roll bar to improve vehicle handling characteristics by using the flexible body dynamic simulation with consideration of the step and single sinusoidal steering input tests. Through simulation, it was learned that the proposed control strategy could reduce the time of stabilization by 54.08% and suppress undesired handling behaviors in the step steering input test. Moreover, at high speed, the original unsteady condition became stabilized with little sacrifice in yaw velocity. In the single sinusoidal steering input test, the time of stabilization could be reduced by 8.43% and with 14.6% less yaw angle changes in the improved design. The overall handling was improved.

Anti-Roll Bar Design and Material Selection for the Torsion Member for A Formula Student Vehicle

Anti-Roll Bar Design and Material Selection for the Torsion Member for A Formula Student Vehicle

Performance analysis of a newly designed single air spring running gear for automated people mover (APM)

ABSTRACT The APM 300 running gear structure follows the structural design of the automobile steering drive axle; therefore, the lateral stiffness of the suspension system is considerable, resulting in poor lateral ride comfort. To improve the lateral ride comfort of the vehicle, this paper proposed a new type of running gear called single air spring running gear (SARG), and according to the original loading conditions, the parameters of the SARG air spring are modified. By establishing a theoretical model of linear steady-state curve negotiation of the single-axle tyre running gear, the radial adjusting index is deduced to evaluate the radial performance of the SARG. By establishing the force analysis model of APM rolling in the static state, APM’s flexibility coefficient is obtained to evaluate the anti-overturning capacity. The influence of running gear parameters on the flexibility coefficient is discussed in detail. Based on this, the stiffness of the SARG anti-roll bar is determined. By comparing the dynamic performance of both types of vehicles, the SARG advantages are proved. Finally, several improvements on the SARG structure are proposed for its adaptation to more complex scenario.

Experimental investigation on the mechanical behavior of hybrid bonded (rivet/adhesive) tubular lap joint (composite to metal) under pure torsion

The hybrid joints being used in the design of mechanical structures because of their significant advantages. The tubular lap joints are used widely in aerospace, naval, and transport industries such as rudder and elevator rods, driving shafts, pull push rods, anti-roll bar and stabilizer bar in cars, trucks and trains. The torsional behavior of mechanical, adhesively bonded, and hybrid tubular lap joints for aluminum to aluminum, and composite to aluminum subjected to pure torsion have been investigated experimentally. The effect of outer tube material and thickness, the joint’s type, and cured and post-cured temperature (room temperature and 40 °C), have been investigated experimentally. A fixture and a torsional set-up device have been designed and manufactured to apply the required torque to the joint. The outcomes from composite to aluminum joints confirm that the hybrid joint has 39.5% and 276.6% higher torque capacity than the mechanical joint and adhesively bonded joint, respectively. Furthermore, the cured and post-cured process at 40 °C, increased the maximum torque to failure, 37.6% and 57.1% for adhesively bonded and hybrid (rivet/bonded) joint, respectively. It has been observed that by upgrading the mechanical joint and adhesively bonded joint to the hybrid (rivet/bonded) joint, increasing the amount of joint’s strength and torque capacity in comparison with the increase in the weight of the structure is affordable.

Modelling and finite element analysis of anti-roll bar using ANSYS software

This design and analysis study has been done for the effectiveness of torsion of anti roll bar to a passenger car and influence the handling of vehicle from body roll. Subsequently, the further study on stabilizer bars in the automotive vehicle, especially in traction and braking condition. Stabilizer bars (also known as Traction bars, Sway bars or Anti-roll bars) are used to stabilize a vehicle from excessive chassis roll when the vehicle is running in high traction conditions. Interestingly, the stabilizer bars are generally used on smooth traction conditions. In view of this work has been done to replace the forged Solid stabilizer rod by using a high strength tubular stabilizer bar thereby reducing the weight of the product and increasing the fuel efficiency of the vehicle. The project involves theoretical estimation of torsional stress in the stabilizer bar and validated with Finite Element Analysis (FEA) by using Solid works for modelling the design work and their experimental results were evaluated. Hence, the simulation has done to take part where the result can determined the effectiveness of the anti roll bar fitted to the vehicle.

Trajectory control for tire burst vehicle using the standalone and roll interconnected active suspensions with safety-comfort control strategy

The lateral pulling of tire burst vehicle results in accident and fatality on the highway due to its sudden C.G displacement of the vehicle. Improper steering input leads to detach wheel from vehicle and rollover accident due to the weight transfer towards the flat tire. Therefore, this paper attempts to reduce the lateral velocity and its displacement of the vehicle by producing the force through suspension actuator within the suspension limitation and without affecting the steering characteristics. For the analysis, 4-axle truck with velocity controller and steering system incorporated model was built in AMESim environment, which is exported into Matlab/Simulink for the co-simulation. Hydraulic control valve integrated standalone and roll interconnected active suspension scheme’s state space model was identified in Matlab through simple identification method for the comfort and safety MPC controller design. Finally, the results of passive system with Anti-roll bar (ARB) and without ARB, passive and active roll interconnected suspensions, comfort and coordinated control standalone active suspension system are comprised to illustrate the effectiveness and its control strategy. In addition, this work showcased the motion trajectory of vehicle with a flat tire on running over highway with and without steer maneuver.

Finite element analysis of passenger car transverse stabilizer bar based on NX8.0

The parametric design and finite element analysis of the lateral stabilizer bar of the new energy bus were carried out by using NX8.0, and the structural strength and stiffness of the stabilizer bar were qualitatively analyzed. The simplified methods for different boundary conditions, solving types and finite element models are compared. All the processes are completed under the same software, which ensures the uniformity and editability of the data. Finally, the subject is introduced into the student s computer-aided engineering analysis training program, so that the students” comprehensive ability is improved.

Design, fabrication, and assessment of a hydraulic arm with quick coupling system for tractors

Food production processes have required increasing productivity, efficiency, and agility in mechanized agricultural operations. This study aimed to design and size a hydraulic arm with the quick coupling of implements for the three-point system of category II tractors. For the project design, a product development methodology was used until obtaining the final variant of the tractor-implement coupling system. The draft and its detailing were developed and, in order to validate the concept, the mechanism prototype was fabricated to test its operation on the field. The accelerations working on the three-point hitch system were measured to optimize the design. The data collected served as a database for a structural analysis of the set by the finite element method. The structural analysis simulations showed Von Mises values between 70 and 140 MPa and displacement values between 0.3 and 1.2 mm. These analyses were performed with the combination of the weight force of the implement and the acting accelerations, which presented results for system validation. It was verified that overloads occur in two regions: the lateral stabilizer bars support and the hook. Under extreme conditions, the stabilizer bars extrapolated the yield value of the material, and failures and plastic deformations may occur in these regions. The prototype test proved the agility and practicality of the system. http://dx.doi.org/10.18226/23185279.v8iss1p33

Robust adaptive backstepping sliding mode control for motion mode decoupling of two‐axle vehicles with active kinetic dynamic suspension systems

SummaryA mode decoupling control strategy is proposed for the active Kinetic Dynamic Suspension Systems (KDSS) with electrohydrostatic actuator (EHA) to improve the roll and warp mode performances. A matrix transfer method is employed to derive the modes of body and wheel station motions for full vehicle with active KDSS. The additional mode stiffness produced by the active KDSS is obtained and quantitatively described with the typical physical parameters. A new hierarchical feedback control strategy is proposed for the active KDSS to improve the roll and warp motion performances and simultaneously accounting for nonlinear dynamics of the actuators with hydraulic uncertainties. H∞ static output‐feedback control is employed to obtain the desirable mode forces, and a new projection‐based adaptive backstepping sliding mode tracking controller is designed for EHA to deal with address the nonlinearity and parameters uncertainty. This controller is used to realize the desirable pressure difference of EHA required from the target mode forces. Numerical simulations are presented to compare the roll and warp performances between the active KDSS, conventional spring‐damper suspension, and suspension with antiroll bar under typical excitation conditions. The evaluation indices are normalized and compared with radar chart. The obtained results illustrate that the proposed active KDSS with proposed controller does not produce additional warp motion for vehicle body, and has achieved more reasonable tire force distribution among wheel stations, the roll stability, road holding, and significantly improved ride comfort simultaneously.

Optimization of the Stabilizer Bar by Using Total Scores Method

Optimization of the Stabilizer Bar by Using Total Scores Method

Coordination strategy between AFS and ASB with fault-tolerant mechanism for ground vehicle

In order to improve the performance of ground vehicle equipped with the active front-wheel steering and active stabilizer bar, the coordination for the two systems has been researched. A layered functional framework is proposed: the upper controller coordinates yaw motion with a designed Fuzzy proportional–integral–derivative controller algorithm correcting the outputs of active front-wheel steering and active stabilizer bar; for the middle subsystems, an ideal steering ratio is designed with the Sigmoid function to achieve the active steering, and a sliding mode algorithm is designed to reduce the roll angle; the bottom actuators achieve the control target from the middle layer. In addition, the upper layer has a rebuilt fuzzy rule-based fault-tolerant mechanism that handles the failure of stabilizer bar actuators to guarantee the stability of roll and yaw motion. Finally, the simulation and rapid-control-prototype test for step steering show that the designed algorithm can ensure roll and yaw performance. In consideration of the accidental failure of active stabilizer bar actuators, by actively adjusting the coordinated rules, the system could overcome the contradiction of coupling control and still maintain yaw and roll stability, which improves the active safety.

A Novel Roll and Pitch Estimation Approach for a Ground Vehicle Stability Improvement Using a Low Cost IMU.

Onboard attitude estimation for a ground vehicle is persuaded by its application in active anti-roll bar design. Conventionally, the attitude estimation problem for a ground vehicle is a complex one, and computationally, its solution is very intensive. Lateral load transfer is an important parameter which should be taken in account for all roll stability control systems. This parameter is directly related to vehicle roll angle, which can be measured using devices such as dual antenna global positioning system (GPS) which is a costly technique, and this led to the current work in which we developed a simple and robust attitude estimation technique that is tested on a ground vehicle for roll mitigation. In the first phase Luenberger and Sliding mode observer is implemented using simplest roll dynamics model to measure the roll angle of a vehicle and the validation of results is carried using commercial software, CarSim® (CarSim, Ann Arbor, MI, USA). In the second phase of research, complementary and Kalman filters have been designed for attitude estimation. In the third phase, a low-cost inertial measurement unit (IMU) is mounted on a vehicle, and both the complementary filter (CF) and Kalman filter (KF) are applied independently to measure the data for both smooth and uneven terrains at four different frequencies. We compared the simulated and real-time results of roll and pitch angles obtained using the complementary and Kalman filters. Using the proposed method, the achieved root mean square error (RMSE) is less than 0.73 degree for pitch and 0.68 degree for roll, with a sample time of 2 ms. Thus, a warning signal can be generated to mitigate roll over. Hence, we claim that our proposed method can provide a low-cost solution to the roll-over problem for a road vehicle.

Influence of shock absorber damping rates on the fatigue of anti-roll bars of a commercial vehicle

Within the framework of an integrated product development, the main objective of this study is to assess the influence of shock absorber damping rates on the fatigue of anti-roll bars of a commercial vehicle. In this regard, force and displacement data have been collected in a durability test track with an instrumented bus on curb weight (CW) and gross axle weight rating (GAWR). Based on the theory of fatigue damage accumulation, the durability of each anti-roll bar of a bus (front and rear suspension) was assessed for three different shock absorber damping rates. Statistical significance between different shock absorbers has been identified for both bars on both loading conditions. The results pointed out that, in some cases, a softer damper could reduce by almost half the fatigue life of an anti-roll bar when compared to the same bar with stiffer dampers.

Influence of shock absorber damping rates on the fatigue of anti-roll bars of a commercial vehicle

Within the framework of an integrated product development, the main objective of this study is to assess the influence of shock absorber damping rates on the fatigue of anti-roll bars of a commercial vehicle. In this regard, force and displacement data have been collected in a durability test track with an instrumented bus on curb weight (CW) and gross axle weight rating (GAWR). Based on the theory of fatigue damage accumulation, the durability of each anti-roll bar of a bus (front and rear suspension) was assessed for three different shock absorber damping rates. Statistical significance between different shock absorbers has been identified for both bars on both loading conditions. The results pointed out that, in some cases, a softer damper could reduce by almost half the fatigue life of an anti-roll bar when compared to the same bar with stiffer dampers.

Reform and exploration of computer aided design and Analysis Course under the background of “new engineering”

In response to the requirements of new engineering construction and reform, the new experimental teaching mode of the comprehensive practice link of computer-aided engineering analysis course was explored, and the “finite element analysis of the lateral stabilizer bar of new energy bus” was introduced into the comprehensive practice of the course to train students’ autonomy learning ability. At the same time, it has improved students’ scientific research and teamwork ability, and used project-based teaching as a link to open up the separation between undergraduate teaching and postgraduate teaching, cultivated students’ ability to continue learning, strengthened the combination of theoretical knowledge and engineering application, and improved student in solving the ability of the problem. It provides a reference for the curriculum reform under the background of “new engineering”.

On the Design of Yaw Rate Control via Variable Front-to-Total Anti-Roll Moment Distribution

In vehicle dynamics, yaw rate control is used to improve the cornering response in steady-state and transient conditions. This can be achieved through an appropriate anti-roll moment distribution between the front and rear axles of a vehicle with controllable suspension actuators. Such control action alters the load transfer distribution, which in turn provokes a lateral tire force variation. With respect to the extensive set of papers from the literature discussing yaw rate tracking through active suspension control, this study presents: i) A detailed analysis of the effect of the load transfer on the lateral axle force and cornering stiffness; ii) A novel linearized single-track vehicle model formulation for control system design, based on the results in i); and iii) An optimization-based routine for the design of the non-linear feedforward contribution of the control action. The resulting feedforward-feedback controller is assessed through: a) Simulations with an experimentally validated model of a vehicle with active anti-roll bars (case study 1); and b) Experimental tests on a vehicle prototype with an active suspension system (case study 2).