Road Wheel Research Articles

Parametric excitation and wavelet transform analysis of a ground vehicle propeller shaft

This paper proposes a numerical model for analyzing torsional vibration of a ground vehicle propeller shaft system. By considering the elasticity and energy of the propeller system, a Lagrangian approach has been used to derive the equation of motion, yielding a highly nonlinear three degree-of-freedom system with five coupled inertias. The model takes into account the dynamics of a Hooke’s joint, a crack-induced parametric excitation, tractive torque at the driving wheels and transient vibration of a rear drive ground vehicle transmission. The forces exciting the vibrations of the propeller shaft system are evaluated by quantifying the tractive forces at the road wheels, Hooke’s joint force, the crack force and the forces emanating from the engine through the clutch and gear box. Subsequently, the forces are projected onto the propeller shaft by either direct coupling or by gearing. Consequently, the nonstationary response of the system in various scenarios has been determined and evaluated by a wavelet transform. By analysis, it is demonstrated that the model is useful for investigating nonlinear vibration of a typical propeller shaft system used in light ground vehicles.

PERFECT AND IMPERFECT NONHOLONOMIC KINEMATIC CONNECTIONS OF THE ROAD WHEEL WITH SURFACE

In the work there are various types of equations describing nonholonomic kinematic connections of the road wheel with the supporting surface. The authors deal with evidence of the adequacy of the results of the pilot studies, and provide justification for the use of each equation type.

A Conjugate Gradient-Based BPTT-Like Optimal Control Algorithm With Vehicle Dynamics Control Application

The paper presents a gradient-based algorithm for optimal control of nonlinear multivariable systems with control and state vectors constraints. The algorithm has a backward-in-time recurrent structure similar to the backpropagation-through-time algorithm, which is mostly used as a learning algorithm for dynamic neural networks. Other main features of the algorithm include the use of higher order Adams time-discretization schemes, numerical calculation of Jacobians, and advanced conjugate gradient methods for favorable convergence properties. The algorithm performance is illustrated on an example of off-line vehicle dynamics control optimization based on a realistic high-order vehicle model. The optimized control variables are active rear differential torque transfer and active rear steering road wheel angle, while the optimization tasks are trajectory tracking and roll minimization for a double lane change maneuver.

The Dynamic Finite Element Analysis of Shearer’s Running Gear Based on LS-DYNA

Base on contact kinetics finite element theory, proceed secondary development of road wheel and pin mesh’s nonlinear dynamic contact analysis in LS-DYNA module, and carry out contrast of simulation analysis, achieved stress, strain and dynamic identities that caused by meshing impact in the whole meshing process, accord with practice, can instruct product practice design.

Comparison of PID and Fuzzy Controller for Automobile Suspension System

The main aim of suspension system is to isolate a vehicle body from road irregularities in order to maximize passenger ride comfort and retain continuous road wheel contact in order to provide road holding. The aim of the work described in the paper was to illustrate the application of fuzzy logic technique to the control of a continuously damping automotive suspension system. The ride comfort is improved by means of the reduction of the body acceleration caused by the car body when road disturbances from smooth road and real road roughness. The paper describes also the model and controller used in the study and discusses the vehicle response results obtained from a range of road input simulations. In the conclusion, a comparison of active suspension fuzzy control and Proportional Integration derivative (PID) control is shown using MATLAB simulations.

Construction and Simulation of a 2S1 Tracked Vehicle Model and its Verification Using Vertical Forces on the Road Wheels while Overcoming a Single Obstacle

We present information about construction tasks of tracked vehicle model in MSC.ADAMS computer program. Kinematic and dynamic relationships inside entire suspension system are described here. Elements of the vehicle are grouped in few subsystems, like suspension, wheels or tracks. The significant accent is put on the tracks with its force connections. Those connections are between all track links as also between wheels, links and ground surface. Also significant accent are put on damping value estimation. It is estimated based on tolerance area of characteristics of real damper element, which is applied in this type of vehicles. In next part of the article, process of appropriate damping characteristics selection is described. This process is applied for high fidelity model building.

Research on New Varying Gear Ratio System

A new automotive varying gear ratio system(VGRS)is introduced in this paper. Based on the analysis of foreign advanced theory in this field, a relationship among road wheel angle, steering wheel angle and vehicle speed is derived in order to achieve the optimum steering control for cornering and emergency maneuvers, whilst retaining the high-speed stability.

Comparing Pid And Fuzzy Logic Control A Quarter-car Suspension System

The main aim of suspension system is to isolate a vehicle body from road irregularities in order to maximize passenger ride comfort and retain continuous road wheel contact in order to provide road holding. Theaim of the work described in the paper was to illustrate theapplication of fuzzy logic technique to the control of a continuously damping automotive suspension systemThe ride comfort is improved by means of thereduction of the body acceleration caused by the car body whenroad disturbances from smooth road and realroad roughness.The paper describes also the model and controller used in thestudy and discusses the vehicle response results obtained from a range of road input simulations In the conclusion, a comparison of active suspension fuzzy control and Proportional Integration derivative (PID) control is shown using MATLAB simulations.

Semiempirical model of a wheel-soil system

Developing new concepts for the prediction of off-road traction is becoming essential as an increasing number of sport utility vehicles (SUVs), sport activity vehicles (SAVs), and other off-road vehicles arrive on the market. The prediction of off-road traction is a difficult problem because of the number of factors affecting wheel performance on soft soils or snow. Most of the existing methods for wheel-soil thrust prediction are based on Coulomb’s equation, in which stresses acting on the wheel-soil contact patch are analyzed. The objective of this work was to develop a new method to infer mathematical models of a wheel-soil system in which soil-stress states are correlated with the forces acting on a road wheel. A set of model equations is obtained by means of the system identification method with the use of experimental data gathered in the field with real vehicles. This paper includes a description of the experimental setup, procedures, and methods used in the tests. The experimental method is based on simultaneous measurements of the soil-stress state and wheel forces during test runs of an instrumented vehicle over soft soil surfaces. Soil-stress states consist of three principal stresses and their direction cosines, which are determined with the use of a stress state transducer (SST) placed at a depth of 15–30 cm under the wheels. Longitudinal, vertical, and transverse wheel forces are measured with a six-element wheel force transducer. The wheel forces obtained in the test runs are correlated with the respective soil stresses. Based on the data, three families of models were obtained by means of the system identification method.

Burst Oscillations in the Accelerating Bicycle

The purpose of this paper is to study the dynamics of the accelerating bicycle. It is shown that time-scale separation can be used to study the oscillatory characteristics of the accelerating machine using time-invariant models. These models are used to explain practically observed wobble-mode bursting oscillations that are associated most frequently with down-hill riding. If the vehicle is cornering under constant acceleration, at a fixed roll angle, it is shown that for low values of acceleration (and braking), it follows closely a logarithmic spiral shaped trajectory. The studies presented are facilitated by a novel adaptive control scheme that centers the machine’s trajectory on any arbitrary point in the ground plane. The influences of cambered road surfaces are also investigated. The bicycle model employed is an extension of that originally developed by Whipple, and comprises two road wheels and two laterally-symmetric frame assemblies that are free to rotate relative to each other along an inclined steering axis. For the most part, the front frame is treated as being flexible and the bicycle is fitted with force generating road tires, rather than classical nonholonomic rolling constraints. This research provides the ground work required for generating more complex dynamic models for high-performance motorcycle studies.

New extrusion process of Mg alloy automobile wheels

The recent research and development of forged magnesium road wheel were reviewed. Methods of flow-forming, spin forging of manufacturing a forged magnesium alloy wheel were introduced. A new extrusion method was investigated especially. Extrusion from hollow billet was proposed in order to enhance the strength of spoke portion and reduce the maximum forming load. By means of the developed technique, the one-piece Mg wheels were produced successfully by extrusion from AZ80+ alloy. At the same time, the existing problems on the research and development of forged magnesium road wheel were analyzed. The impact testing, radial fatigue testing and bending fatigue testing results show that AZ80+ wheel can meet application requirement in automobile industry.

H ∞ robust control of semi-active Macpherson suspension system: new applied design

In this paper, the performance of a robust control scheme for a Macpherson suspension system is investigated using new dynamic and kinematic models. While the new dynamic model incorporates the kinematics of the suspension in order to have a superior description of the plant dynamics, the three-dimensional kinematic model is used to evaluate the wheel motion subject to controlled force variation. A new definition of the measurement of the wheel–road contact is proposed based on the real function of the control arm. In addition, it is recommended to integrate the vertical displacement of the chassis in the formulation of the control design in order to improve wheel motions. It is shown that the robust semi-active suspension system has superior performance compared with those of a modified skyhook controller system and a passive system.

Steering pull and drift considering road wheel alignment tolerance during high-speed driving

This paper describes an analytical vehicle model and a full-vehicle model that consider the effect of suspension geometry on steering pull and drift. Steering pull occurs when a driver applies steering wheel torque to keep a straight-line course, and steering drift means the tendency to deviate from the intended path with a free steering wheel. In designing a chassis system, it is crucial to establish a suspension insensitive to steering pull and drift regardless of manufacturing tolerances. Simulation results show that larger caster trail at the front wheel leads a less-sensitive vehicle towards steering pull and drift, since caster trail reduces the equilibrium slip angle difference between pull and drift by considerably changing the aligning moment diagram. These wheel alignment sensitivities are validated by experimental measurement of drift distance.

On the castor dynamic behavior

Abstract In this paper, a model describing the castor three-dimensional dynamic behavior, is presented. A procedure, based on the Udwadia–Kalaba formulation has been implemented to write the castor non-linear motion equations. The model takes into account the flexural and lateral compliance of the castor frame and the phenomena related to the wheel rotation. To prescind from the wheel–road interaction parameters, the hypothesis of no sideslip of the wheel has been adopted but other tire models can be easily implemented. The non-linear system stability is evaluated integrating the motion equations and performing a fitting procedure on the natural steering oscillation.

Vehicle steering returnability with maximum steering wheel angle at low speeds

In this paper, an analytical model with suitable vehicle parameters, together with a multi-body model is proposed to predict steering returnability in low-speed cornering with what is expected to be adequate precision as the steering wheel moves from lock to lock. This model shows how the steering response can be interpreted in terms of vertical force, lateral force with aligning moment, and longitudinal force. The simulation results show that vertical steering rack forces increase in the restoring direction according to steering rack displacement for both the inner and outer wheels. As lateral forces due to side-slip angle are directed toward the medial plane of the vehicle in both wheels, the outer wheel pushes the steering wheel in the returning direction while the inner wheel does not. In order to improve steering returnability, it is possible to increase the total steering rack force in both road wheels through adjustments to the kingpin axis and steering angle. This approach is useful for setting up a proper suspension geometry during conceptual chassis design.

Torque feedback on the steering wheel of agricultural vehicles

The torque feedback on the steering wheel of automobiles, also known as “road feel”, is important in some driving situations. New electronic and electro-hydraulic steering systems remove the mechanical connection between the road wheel and the steering wheel, but make it possible for the designer to provide any desired torque feedback to the driver. This study was performed to investigate whether the operation of agricultural vehicles can be made easier by the nature of the torque feedback on the steering wheel. For operators of agricultural vehicles, this feedback can be particularly important when they simultaneously monitor the operation of an attached machine. Experiments were performed in the field and in a tractor-driving simulator in which experienced tractor drivers drove in parallel swathing mode with the help of a GPS lightbar. Torque feedback on a real tractors’ steering wheel was measured and implemented in the simulator. Also, in different tractor simulator runs, torque feedback on the steering wheel was computed based on steering wheel angle, the lateral force on the ground wheel, and the projected driving error. Analysis showed that when steering is the only task, the behavior and performance of the operator does not significantly change if the torque feedback is removed. However, when the operator has to perform a monitoring task as well, the performance of the operator was significantly improved by providing a torque feedback that was a function of the projected driving error. Also, when the feedback torque is a function of steering wheel angle, tending to move the steering wheel towards zero steering angle position, the operator achieved a higher performance, presumably by reducing unnecessary steering inputs.

Influence of Road Camber on Motorcycle Stability

This paper studies the influence of road camber on the stability of single-track road vehicles. Road camber changes the magnitude and direction of the tire force and moment vectors relative to the wheels, as well as the combined-force limit one might obtain from the road tires. Camber-induced changes in the tire force and moment systems have knock-on consequences for the vehicle’s stability. The study makes use of computer simulations that exploit a high-fidelity motorcycle model whose parameter set is based on a Suzuki GSX-R1000 sports machine. In order to study camber-induced stability trends for a range of machine speeds and roll angles, we study the machine dynamics as the vehicle travels over the surface of a right circular cone. Conical road surfaces allow the machine to operate at a constant steady-state speed, a constant roll angle, and a constant road camber angle. The local road-tire contact behavior is analyzed by approximating the cone surface by moving tangent planes located under the road wheels. There is novelty in the way in which adaptive controllers are used to center the vehicle’s trajectory on a cone, which has its apex at the origin of the inertial reference frame. The results show that at low speed both the weave- and wobble-mode stabilities are at a maximum when the machine is perpendicular to the road surface. This trend is reversed at high speed, since the weave- and wobble-mode dampings are minimized by running conditions in which the wheels are orthogonal to the road. As a result, positive camber, which is often introduced by road builders to aid drainage and enhance the friction limit of four-wheeled vehicle tires, might be detrimental to the stability of two-wheeled machines.

Experimental evaluation of observers for tire–road forces, sideslip angle and wheel cornering stiffness

This paper proposes a new estimation process to estimate tire–road forces, sideslip angle and wheel cornering stiffness. This method uses measurements from currently–available standard sensors. The estimation process is separated into two blocks: the first block contains an observer whose principal role is to calculate tire–road forces without a descriptive force model, while in the second block an observer estimates sideslip angle and cornering stiffness with an adaptive tire-force model. The different observers are based on an Extended Kalman Filter method. Concerning the vehicle model, for observability reasons, the rear longitudinal forces are neglected relative to the front longitudinal forces. The estimation process was applied and compared to real experimental data, notably wheel force measurements. Experimental results show the accuracy and potential of the estimation process, and a limitation in the estimation of the cornering stiffness.

Flat versus Curved Contact Surfaces Effect on Consumer P-Metric and LT Tire Operating Temperatures

Abstract Rolling stress and resultant operating temperature is critical to the endurance of a tire. There are fundamental differences between the tire stresses when operating on a flat surface, as experienced in normal highway use, and on a cylindrical laboratory test wheel. Even though there are substantially higher tire stresses and temperatures on a curved test wheel, nonetheless, cylindrical road wheels are widely used with the industry for tire endurance testing. Therefore, it is important to consider the severity of test conditions intended for a flat surface and the equivalent severity on the curved surface in order to avoid subjecting the tire to unrealistic stresses and temperatures. In this study, temperature measurements were made at the tire belt edge and centerline, for both flat and curved surfaces, under designed ranges of load, pressure, and speed conditions. Statistical regression models that predict the temperatures at the tire centerline and belt edge locations are developed and discussed. A simple yet consistent conversion from flat to curved conditions is provided so that equivalent tire temperatures are obtained. Flat highway conditions are derived that are temperature equivalent solutions to each of the FMVSS139 step test conditions.

Development of high-mobility tracked vehicles for over snow operations

This paper describes a detailed investigation into the effects of some of the major design features on the mobility of tracked vehicles over snow. The investigation was carried out using the latest version of an advanced computer simulation model, known as NTVPM, developed under the auspices of Vehicle Systems Development Corporation (VSDC), Ottawa, Ontario, Canada. Results show that the road wheel system configuration, initial track tension (i.e., the tension in the track system when the vehicle is stationary on a level, hard ground) and track width have significant effects on vehicle mobility over snow. On deep snow where the vehicle belly (hull) contacts the snow surface, the location of the centre of gravity (C.G.) of the sprung weight in the longitudinal direction has a noticeable effect on vehicle mobility, as it affects the attitude of the belly and the belly–snow interaction. Based on the investigation, a conceptual high-mobility tracked vehicle for over snow operations is discussed. Results of this study will provide the vehicle designer with guiding principles for the development of high-mobility tracked vehicles. It also demonstrates that NTVPM is a useful and effective tool for design and performance evaluation of tracked vehicles from a traction perspective.