Multi-axle Vehicle Research Articles

A Novel Integrated Stability Control Based on Differential Braking and Active Steering for Four-axle Trucks

Differential braking and active steering have already been integrated to overcome their shortcomings. However, existing research mainly focuses on two-axle vehicles and controllers are mostly designed to use one control method to improve the other. Moreover, many experiments are needed to improve the robustness; therefore, these control methods are underutilized. This paper proposes an integrated control system specially designed for multi-axle vehicles, in which the desired lateral force and yaw moment of vehicles are determined by the sliding mode control algorithm. The output of the sliding mode control is distributed to the suitable wheels based on the abilities and potentials of the two control methods. Moreover, in this method, fewer experiments are needed, and the robustness and simultaneity are both guaranteed. To simplify the optimization system and to improve the computation speed, seven simple optimization subsystems are designed for the determination of control outputs on each wheel. The simulation results show that the proposed controller obviously enhances the stability of multi-axle trucks. The system improves 68% of the safe velocity, and its performance is much better than both differential braking and active steering. This research proposes an integrated control system that can simultaneously invoke differential braking and active steering of multi-axle vehicles to fully utilize the abilities and potentials of the two control methods.

Determination of dynamic axle load using suspension deflection method for the load distribution optimisation of multi-axle vehicles

Identification of dynamic axle loads in multiple axle vehicles requires complex calculation methods because of its hyper static solving necessity. In this study, suspension deflection method is proposed to determine the dynamic axle loads for optimisation of load distribution of a multi-axle vehicle having more than two axles. The determination of the dynamic axle loads is performed for driving conditions with a climbing angle and a longitudinal acceleration to optimise the loads at the axles of the vehicle using suspension deflection method. General equations and calculation methodology are presented for a multi-axle vehicle and a numerical example is implemented using the suspension deflection method for a four-axle vehicle as a case study. Finally, it is shown that the suspension deflection method is more simple and useful than other approaches to define the dynamic axle loads for an optimisation study of the vehicles which have multiple axles.

Determination of dynamic axle load using suspension deflection method for the load distribution optimisation of multi-axle vehicles

Identification of dynamic axle loads in multiple axle vehicles requires complex calculation methods because of its hyper static solving necessity. In this study, suspension deflection method is proposed to determine the dynamic axle loads for optimisation of load distribution of a multi-axle vehicle having more than two axles. The determination of the dynamic axle loads is performed for driving conditions with a climbing angle and a longitudinal acceleration to optimise the loads at the axles of the vehicle using suspension deflection method. General equations and calculation methodology are presented for a multi-axle vehicle and a numerical example is implemented using the suspension deflection method for a four-axle vehicle as a case study. Finally, it is shown that the suspension deflection method is more simple and useful than other approaches to define the dynamic axle loads for an optimisation study of the vehicles which have multiple axles.

Structural Analysis and Comparison of Multiaxle Vehicle Suspension System

Leaf springs are main part of the suspension system of any automobile. These are used in heavy commercial vehicles such as vans and trucks, Multiaxle vehicles. For heavy vehicles, they have the advantage of spreading the load more widely over the vehicle's chassis. Therefore, this type of suspension does not provide good riding comfort. The inter-leaf friction between the leaf springs affects the riding comfort. But still they are suited best for heavy duty commercial vehicles. It is a structural member and it absorbs the energy by its deflection and in current scenario, automobile industry is heading their way to lighten up their vehicle as much as they can without decrease in performance. This paper includes the study and comparison of existing leaf spring of heavy duty vehicles, considering recent as well as conventional materials. The dimensions of existing conventional leaf spring of TATA LS3718 were taken and modelled in CATIA software and then FEA is performed in high optimization tool ANSYS. The objective is to compare load carrying capacity, stiffness and weight savings and to show the potential of composite against conventional steel. Theoretical and software based results are presented and compared for validation.

Оценка боковой жесткости пневмогидравлической подвески многоосной колесной машины с использованием имитационного математического моделирования

Оценка боковой жесткости пневмогидравлической подвески многоосной колесной машины с использованием имитационного математического моделирования

Adaptive Robust Control of Multi-Axle Vehicle Electro-Hydraulic Power Steering System With Uncertain Tire Steering Resistance Moment

To investigate the unknown (uncertain) tire steering resistance moment and model uncertainties in a multi-axle vehicle electro-hydraulic power steering system (EHPSS), including the steering mechanisms, valve-controlled double hydraulic actuators, and heavy-duty tires, an adaptive robust control algorithm is developed to estimate the tire steering resistance moment online and compensate for the model uncertainties of EHPSS. The proposed control strategy consists of an adaptive control law and a robust controller which are based on a Lyapunov function. The adaptive control law is employed to update estimated values of the (unknown) tire steering resistance moment and parameter uncertainties in the EHPSS, whereas complicated nonlinearities are addressed by the robust controller. All adaptive laws of the EHPSS and controller, which can impede parametric uncertainties and stabilize the EHPSS, are synthesized by backstepping techniques. The comparative simulation results demonstrate that the proposed adaptive robust control scheme can achieve the desired performance for feasible tracking trajectories despite the existence of an uncertain tire steering resistance moment and external disturbance in the EHPSS.

Multi-axle vehicle dynamics with roll

The classic two-axle yaw-plane or bicycle model has historically provided basic insight into vehicle handling. It has previously been augmented with suspension effects to allow sprung mass roll, and separately more recently to accommodate multiple axles, any of which could be steering. In this work these two extensions of the yaw-plane model are combined, to form a dynamic model of a vehicle with an arbitrary number of axles, any of which could be steered, and also with a suspension that allows sprung mass roll. Convention and nomenclature are introduced to allow compact expression. As such this work introduces the most general dynamic yaw-plane model to date.

Multi-axle vehicle dynamics with roll

The classic two-axle yaw-plane or bicycle model has historically provided basic insight into vehicle handling. It has previously been augmented with suspension effects to allow sprung mass roll, and separately more recently to accommodate multiple axles, any of which could be steering. In this work these two extensions of the yaw-plane model are combined, to form a dynamic model of a vehicle with an arbitrary number of axles, any of which could be steered, and also with a suspension that allows sprung mass roll. Convention and nomenclature are introduced to allow compact expression. As such this work introduces the most general dynamic yaw-plane model to date.

Analysis and optimization of coupled vibration between substructures of a multi-axle vehicle

The vibration from transport vehicles may negatively affect the ride comfort in the cab and the product safety in the carriage. A 15 degrees of freedom vehicle model consisted of a cab, a carriage, a chassis, and mounts and suspensions between them are introduced to present the vibration behavior of a three-axle vehicle. Two indices, the coupling factor and the vibration attenuation factor, are employed to quantify the correlation between structures and the vibration isolation capability of subsystems. A sensitivity analysis is carried out with a 43-factor optimal Latin hypercube design, concerning the effect of mass properties, geometries, stiffness, and damping on the vibration coupling effect and the vibration attenuation of subsystems. Results show obvious trade-offs between the vibration coupling effect and the vibration attenuation among different subsystems. Based on the significant factor identified, multi-objective optimizations are conducted to improve the vibration performance of both the cab and the carriage and simultaneously reduce the correlations between structures using different algorithms. Comparison between different optimal results indicates that a compromise can be achieved between the ride comfort and the cargo safety based on a lightweight constraint.

Matching and optimising analysis of multi-axle steering vehicle steering system

The analysis of the multi-axle steering link mechanism (MASLM) link forces provides the foundation for the mechanism's design. The matching level between the steering cylinder driving torque and the tyre pivot steering resistance torque can dramatically influence the link forces. In this study, the accuracy of the tyre resistance torque formula reached 90.7%. A steady kinematic-mechanical coupling model of the MASLM was built modularly, and a method of calculating the link forces and steering hydraulic pressure is proposed. To verify the coupling models, an all-terrain QAY130 crane was chosen for simulation and testing. Two vehicle models were built by using the Adams and Matlab software, respectively. The discrepancies were less than 23.5% between the test values and the predicted values for the previous two models, but exhibited similar variation trends. The installation site and diameter parameters of the steering cylinders were optimised to minimise the link forces.

The Multi-axle Trucks and the Indian Transport Industry: A Review

A review of various scholarly articles, working papers and professional studies which deal with four distinct aspects of transport industry utilizing multi-axle trucks; which are-(i) growth of multi axle long distance haulers vis-a-vis road and infrastructural development;(ii) multi axle trucks and their inherent advantages (over two axle vehicles) in long haulage applications;(iii) brand image and any impact it has on purchase decision of Multi Axle Trucks and(iv)the differences in the Business models of various Multi-axle Vehicle Manufacturers in India.

Modeling, simulation, and experimental validation of electro-hydraulic power steering system in multi-axle vehicles

An accurate electro-hydraulic power steering system (EHPSS) model is essential to analyze dynamic steering performance and advanced nonlinear control. The main obstacle to establish an accurate model is the complex structure, including steering mechanism, valve controlled dual hydraulic-actuator, and heavy duty tires. This paper constructs a suitable model incorporating these parts, based on a Lagrange equation describing the steering trapezoid mechanism and dual cylinder hydraulic dynamics, regarding steering resisting moment as an external load. A simplified tire model is used to represent the tire basic steering load characteristics. Due to the complexity of the kinematic relationship in the model, several expressions are fitted using back propagation neural networks to significantly reduce calculation difficulty. Experimental measurements and simulation using Matlab/Simulink and experiment are realized for the case of in situ steering, and the results validate the proposed model accuracy. Thus, the proposed model is suitable to analyze the system and design advanced controllers.

A comparative study of equivalent modelling for multi-axle vehicle

ABSTRACTIn this paper, equivalent modelling methods of a multi-axle vehicle are presented and compared. Firstly, for the sake of comparison, a single-track model of a three-axle and a two-axle vehicle is developed, and then existing equivalent modelling derivations are presented and discussed. Next, the proposed model-based dynamic equivalence of force/moment at the centre of gravity (CG) is introduced and optimised. It represents the approximately equivalent steady-state and transient response of the yaw rate and side slip angle, which allows different cornering stiffness on the central and rear axle. Finally, to demonstrate how the proposed method is advantageous to the other equivalent models available in the literature, different simulation cases are compared in the dimension of time-domain, eigenvalues characteristics and frequency-domain. Furthermore, the proposed method is extended to any multi-axle vehicle configurations and a general expression is formulated.

Analysis of Powertrain Loading Dynamic Characteristics and the Effects on Fatigue Damage

The objective of this study is to investigate the effects of key factors on the powertrain loading dynamic characteristics and fatigue damage. First, the engine and the transmission output shaft torque of a multi-axle vehicle powertrain system were measured by proving grounds (PG) testing and analyzed with a conclusion that the powertrain loading changes were mainly related to three key factors: the mean engine torque, the harmonic engine torque, and the vibration properties of the system. Subsequently, a dynamic model considering the three factors was built and validated by the test data. Finally, fatigue damage of shaft parts and gear parts were calculated to investigate the influence degrees of the three factors. The results show that, the harmonic engine torque and the vibration properties of the powertrain system have a great influence on the fatigue damage of shaft parts, and the mean engine torque is the main factor causing the fatigue damage of gear parts.

On Optimizing Steering Performance of Multi-axle Vehicle Based on Driving Force Control

The steering performance of multi-axle vehicle with independent driving system is affected by the distribution of the wheel driving force. A nonlinear vehicle dynamics model including magic formula tire model for describing 11 DoF four-axle vehicle with dual-front-axle-steering (DFAS) system was presented. The influence of different driving force distribution scheme on the steering performance of the vehicle was analyzed. A control strategy for improving the steady response and transient response of the vehicle steering is proposed. The results show: For the steady response, setting different drive force for internal and external wheels according to the actual steering characteristics of the vehicle can effectively improve its steering characteristics; For the transient response, adopting the zero sideslip angle control strategy and using the PID control algorithm to control the driving force of the outside wheel of tear-two-axle, under angle step input, the vehicle sideslip angle can quickly stabilize to 0 and yaw rate also significantly decreases.

Wavelet-based automatic identification method of axle distribution information

Accurately extracting the axle distribution information of a passing vehicle from bridge dynamic responses experiences a key and challenging step in non-pavement bridge weigh-in-motion (BWIM). In this article, the wavelet transformation is adopted and the wavelet coefficient curve is used as a substitute for dynamic response. The driving frequency is introduced and expanded to multi-axle vehicle, and the wavelet coefficient curve on specific scale corresponding to the driving frequency is confirmed to contain obvious axle information. On this basis, an automatic method for axle distribution information identification is proposed. The specific wavelet scale can be obtained through iterative computing, and the false peaks due to bridge vibration can be eliminated through cross-correlation analysis of the wavelet coefficients of two measure points. The integrand function that corresponds to the maximum value of the cross-correlation function is used to identify the peaks caused by axles. A numerical application of the proposed axle information identification method is carried out. Numerical results demonstrate that this method acquires precise axle information from the responses of an axle-insensitive structure (e.g., girder) and decreases the requirement of sensitivity structure of BWIM. Finally, an experimental study on a full-scale simply supported bridge is also conducted to verify the effectiveness of this method.

Modeling and simulation of multi-axle vehicle powertrain system

Modeling and simulation of multi-axle vehicle powertrain system

Design and analysis of mechanic-hydraulic servo control steering system for pure rolling in multi-axle vehicle

With more axles for multi-axle vehicles, conventional steering trapeziums are unable to let every tire fit Ackermann steering which cause tire wear increasingly more serious. To alleviate this problem, an original mechanic-hydraulic servo steering system with a controllable tie rod is designed. By controlling the angle of one wheel and the length of tie rod, both wheels can be controlled as per default trajectory which implemented Ackermann steering. This article utilized mechanic-hydraulic servo feedback to design a mechanic-hydraulic servo valve which controlled the tie rod accurately. It ensured dynamic characteristics of steering wheels and driving force. To understand inherent characteristics of system, the mathematical model was established. The transfer function was derived, and this high-order system was reduced by Routh approximation. Analyzed natural frequency and the main parameter (the gain coefficient of displacement) which influences the dynamic characteristics had been found out. Analysis shows that the lower the gain coefficient, the higher the speed of response. Moreover, the accurate simulation model of servo system is built on AMESim. Contrasting five groups of simulation results, it is obtained that the influence rule of the gain coefficient is consistent with theoretical analysis. This research provides a useful reference for future nonlinear control.

Разработка шасси многоосного вездеходного транспортного средства с гидрообъемной трансмиссией

Разработка шасси многоосного вездеходного транспортного средства с гидрообъемной трансмиссией

MR Damper Characterization for Implementation of Semi-active Suspension Control

The paper proposes experimental method to characterize the Magnetorheological (MR) damper for realization of the suspension control for multi-axle military vehicle. An ac-curate model of MR damper based on the laws of physics to be embedded in real time controller for suspension system increases the computational load and implementation intricacies attracting higher costs and attendant issues. This paper presents a novel practical based approach to characterize MR dampers using simple experimental set up which, additionally, with the help of simulation technique, aids to assess the dynamic range of MR damper for various parameters of suspension system for vibration control in respect of multi-axle vehicle vehicles. The paper reports experimental investigation for characterization of MR damper through quarter car model. Equivalent damping coefficient is estimated using work diagrams. The governing equations of a quarter car model are formulated analytically and the damping coefficients obtained by experimental investigation have been used for simulation study. Performance analysis in terms of body acceleration, amplitude gain, suspension working space and normalized tyre forces has been carried out. The analysis reveals that with variation of current, there is effective reduction in amplification of the sprung mass displacement at the sprung mass fundamental frequency and improvement in ride comfort. Proposed approach is helpful to achieve better controllability of the MR damper without re-lying on the software based techniques for accounting the behaviour of MR fluid. The method finds practical application for implementation in military multi-axle vehicles.