Showing papers in "Vehicle System Dynamics in 1993"
TL;DR: A review of dynamic modelling of railway track and of the interaction of vehicle and track at frequencies which are sufficiently high for the track's dynamic behaviour to be significant is presented in this paper.
Abstract: A review is presented of dynamic modelling of railway track and of the interaction of vehicle and track at frequencies which are sufficiently high for the track's dynamic behaviour to be significant. Since noise is one of the most important consequences of wheel/rail interaction at high frequencies, the maximum frequency of interest is about 5kHz: the limit of human hearing. The topic is reviewed both historically and in particular with reference to the application of modelling to the solution of practical problems. Good models of the rail, the sleeper and the wheelset are now available for the whole frequency range of interest. However, it is at present impossible to predict either the dynamic behaviour of the railpad and ballast or their long term behaviour. This is regarded as the most promising area for future research.
615 citations
TL;DR: In this paper, a new method of analysis was developed for determining yaw moment and side force of the vehicle with a parameter of the side slip angle at the center of gravity when its center-of-gravity point was fixed.
Abstract: SUMMARY This paper deals with a study to theoretically formulate an effective method of improving vehicle performance, particularly, its characteristics in the nonlinear region, and to verify the feasibility of the proposed method by calculations and examinations. In order to analyze vehicle characteristics in the nonlinear region, a new method of analysis was developed for determining yaw moment and side force of the vehicle with a parameter of the side slip angle at the center of gravity when its center of gravity point was fixed. The study with this new method found that direct yaw moment control by proper distribution of traction and braking forces on the right and left tires could provide a very effective means of stabilizing vehicle characteristics, specifically for acceleration and deceleration, and enlarging the limit of vehicle maneuverability.
304 citations
TL;DR: In this article, different driver models and driver/vehicle/road closed-loop directional control systems are reviewed and compared, and the evaluation methods of vehicle handling quality based on closedloop system dynamics, stability of the closed loop system, and optimization of vehicle design are discussed.
Abstract: Different driver models and driver/vehicle/road closed-loop directional control systems are reviewed and compared. Evaluation methods of vehicle handling quality based on closed-loop system dynamics, stability of the closed-loop system, and optimization of vehicle design are discussed.
157 citations
TL;DR: In this paper, a nonlinear, "sliding" control law is developed and compared with the linear control of a quarter-car active suspension system acting under the effects of coulomb friction.
Abstract: SUMMARY This paper illustrates the use of nonlinear control theory for designing electro-hydraulic active suspensions. A nonlinear, “sliding” control law is developed and compared with the linear control of a quarter-car active suspension system acting under the effects of coulomb friction. A comparison will also be made with a passive quarter-car suspension system. Simulation and experimental results show that nonlinear control performs better than PID control and improves the ride quality compared to a passive suspension.
84 citations
Journal Article•
TL;DR: In this article, the Magic Formula tire model, road surface correction of tire force and momentum data, vehicle and aircraft landing gear simulation, modeling transient nonlinear tire responses, tire force computation model were discussed.
Abstract: Proceedings of a conference held in Delft, Netherlands, in October 1991. Paper topics include the Magic Formula tire model, road surface correction of tire force and momentum data, vehicle and aircraft landing gear simulation, modeling transient nonlinear tire responses, tire force computation model
76 citations
TL;DR: This paper gives a review of multibody simulation software for vehicle system dynamics and finds surveying and benchmarking appear to be useful for guiding decisions.
Abstract: This paper gives a review of multibody simulation software for vehicle system dynamics. Computer aided engineering has moved more strongly into vehicle system dynamics through the development of multibody computer codes. Available software packages are quite numerous and comparisons between them are difficult to make. The comparison problem is multi-objective and it is not feasible to establish the best in any overall sense. However, surveying and benchmarking appear to be useful for guiding decisions. For the covering abstract see IRRD 860691.
69 citations
TL;DR: In this paper, the methods used in railway dynamics to take into account the non Hertzian multi contact patches occurring on a wheel are summarised and some application cases are presented as well as an explanation of the so called “squat” rail deterioration.
Abstract: In the present paper, the methods used in railway dynamics to take into account the non Hertzian multi contact patches occurring on a wheel, are summarised. Some application cases are presented as well as an explanation of the so called “squat” rail deterioration.
59 citations
TL;DR: In this paper, a mathematical simulation and an experimental vehicle were used to clarify vehicle dynamics effected by traction force distribution, not only between the front and rear wheels but also between the left and right wheels.
Abstract: SUMMARY The purpose of this study is to clarify vehicle dynamics effected by traction force distribution, not only between the front and rear wheels but also between the left and right wheels. Contribution of traction force distribution to vehicle turning performance was investigated using a mathematical simulation and an experimental vehicle. The results indicates that the control of traction control distribution between the left and right wheels greatly influences vehicle turning characteristics and improve the performance even in a marginal turning condition.
53 citations
TL;DR: The methods currently being used in North America, Britain and Europe for the safety assessment of rail vehicles are discussed in this article, and conclusions are drawn and some recommendations are made for the future direction of safety assessment methods.
Abstract: The methods currently being used in North America, Britain and Europe for the safety assessment of rail vehicles are discussed. There is considerable disparity between the methods that have been developed in the different countries. These differences, and the possible reasons for them, are discussed in the paper. Finally, conclusions are drawn and some recommendations are made for the future direction of safety assessment methods.
51 citations
TL;DR: In this article, a continuous time control strategy for an active suspension with preview, based on optimal control theory, is presented, which is applied to a two DOF model of the rear side of the tractor of a tractor-semitrailer.
Abstract: A continuous time control strategy for an active suspension with preview, based on optimal control theory, is presented. No approximation is needed to model the time delay between the excitation of the front and the rear wheels. The suspension is applied to a two DOF model of the rear side of the tractor of a tractor-semitrailer. The purpose of the suspension is to reduce either the required suspension working space or the maximum absolute acceleration of the sprung mass, without an increase of the dynamic tire force variation. For a step function as road input, reductions of 65% and 55%, respectively, are possible compared with a passive suspension.
45 citations
TL;DR: In this paper, the Variable Linear Transmission (VLT) was used as a damper in a typical passenger vehicle for regenerative damping in vibration control, which can provide damping nearly identical to that of a passive viscous damper while storing the damped energy.
Abstract: This paper introduces the concept of regenerative damping in vibration control, die storage of energy normally dissipated by a passive viscous damper. A device, the Variable Linear Transmission, is proposed to accomplish this task. Analysis of die proposed device as a damper in a typical passenger vehicle is conducted for die cases in which the device's active component operates ideally and with activation dynamics included. Results indicate that regenerative vibration control is feasible and can provide damping nearly identical to that of a passive viscous damper while storing the damped energy.
TL;DR: In this article, the authors used Kalker's contact software to solve the non-Hertzian case for normal and tangential forces, demonstrating that the assumption of summing Hertzian contacts is realistic provided that enough ellipses are considered.
Abstract: In a previous paper [1], a new method using ‘multi-Hertzian’ elasticity for identifying equivalent parameters of railway wheelsets rolling on defined tracks was presented. Another method also using Hertzian elasticity [2] has produced different results. Without knowing the origin of these discrepancies, the question was asked whether any of these methods could adequately describe actual non-Hertzian contacts. This paper, using as a basis Kalker's ‘Contact’ software which solves the non-Hertzian case for normal and tangential forces, answers this question, demonstrating that the assumption of summing Hertzian contacts is realistic provided that enough ellipses are considered. On this basis, the ‘equivalent conicity’ of the standard wheelset equipped with S1002 profiles rolling on UIC60 (1/40) rails is analysed in the range of small lateral displacements: around 2 mm it amounts to between 0.13 and 0.16. It is demonstrated that, due to actual wheel and rail elasticity, linearization of rigid profile...
TL;DR: In this article, a non-amplifying suspension system with a semi-active damping is developed for road and terrain vehicles, where the use of an electronically controlled rotational damper has been studied theoretically.
Abstract: The main shortcoming of vehicle suspension systems is the amplification of input vibrations at the resonant frequency. A non-amplifying suspension system with a semi-active damping is being developed. The use of an electronically controlled rotational damper has been studied theoretically. A new sprung seat is being designed for the improvement of the working conditions for drivers of road and terrain vehicles.
TL;DR: In this paper, the authors derived a method of controlling four wheel steering using optimal control theory to minimize the side-slip angle at the center of gravity, and showed that the sideslip angle is reduced to zero even in the transient state, and that understeer characteristic and frequency response can be changed regardless of the vehicle static margin.
Abstract: SUMMARY This paper derives a method of controlling four wheel steering using optimal control theory. The purpose of control is to minimize the sideslip angle at the center of gravity. The control method feeds forward the steering wheel angle and feeds back the yaw velocity and the sideslip angle to the front and rear wheel angles. Theoretical studies show that the sideslip angle is reduced to zero even in the transient state, and that the understeer characteristic and frequency response can be changed regardless of the vehicle static margin. This Paper also examines various characteristics of the influence of the side force nonlinearities of tires and crosswinds.
TL;DR: In this article, a dynamical model is presented to analyse the stability of motion of the two-wheeled Fokker F.28-like landing gear including tyres, which is equally applicable to similar landing gears.
Abstract: A dynamical model is presented to analyse the stability of motion of the two-wheeled ‘Fokker F.28-like’ landing gear including tyres. The model is equally applicable to similar landing gears. The influence of the introduction of a specially designed torsional damper on the dynamical behaviour of the landing gear-tyre combination is investigated. Results of the stability calculations are supported by test results.
TL;DR: In this article, an active suspension with preview is tested for rounded pulses and a stochastic road surface, and is compared to a passive suspension, and the performance improvement obtained for a step function as road surface is not achieved but the improvement still significant.
Abstract: SUMMARY An active suspension with preview is tested for rounded pulses and a stochastic road surface, and is compared to a passive suspension. The spectacular performance improvement obtained for a step function as road surface is not achieved but the improvement is still significant. The frequency response of the active suspension is determined for comparison with some suspension systems found in literature An observer to reconstruct the preview information is presented. No model of the road surface is needed. From simulations, it appears that the observer reconstructs both deterministic and stochastic road surfaces satisfactory. However, the influence of measurement noise is not reduced sufficiently.
TL;DR: In SIMPACK the kinematics of elastic bodies are developed up to terms of second order in order to take stress stiffening effects of elastic deformation into account.
Abstract: The SIMPACK software package is a tool that aids engineers in simulating, analysing and designing all kinds of mechanical systems, for instance vehicles The equations of motion are formulated in terms of relative coordinates, and can be generated symbolically and numerically in an implicit and explicit form For realistic modelling, it is sometimes necessary to use elastic instead of rigid bodies In SIMPACK the kinematics of elastic bodies are developed up to terms of second order in order to take stress stiffening effects of elastic deformation into account For the covering abstract see IRRD 860691
TL;DR: In this article, the authors developed a mathematical model of a limited bandwidth hydro-pneumatic suspension that is incorporated into a vehicle handling model to evaluate a suitable control strategy for eliminating body roll during a cornering manoeuvre.
Abstract: SUMMARY The development of a mathematical model of a limited bandwidth hydro-pneumatic suspension that is incorporated into a vehicle handling model is described. The combined model is used to evaluate a suitable control strategy for eliminating body roll during a cornering manoeuvre. The philosophy behind the roll control strategy has been to use feedback measurements of the body motions which do not compromise the ride control. A study of the influence of the position of the body motion feedback transducer on the effectiveness of the system to reduce the body roll is presented. Non-linear modelling of the suspension components for a 0.8g cornering manoeuvre has revealed performance limitations. Conclusions are drawn as to the effectiveness of the control scheme.
TL;DR: In this article, the performance of neural networks to be used for identification and optimal control of nonlinear vehicle suspensions is analyzed, where a neuro-observer is trained to identify the inverse dynamics of the front suspension so that front road disturbances can be identified and used to improve the response of the rear suspension.
Abstract: SUMMARY The performance of neural networks to be used for identification and optimal control of nonlinear vehicle suspensions is analyzed. It is shown that neuro-vehicle models can be efficiently trained to identify the dynamical characteristics of actual vehicle suspensions. After trained, this neuro-vehicle is used to train both front and rear suspension neuro-controllers under a nonlinear rear preview control scheme. To do that, a neuro-observer is trained to identify the inverse dynamics of the front suspension so that front road disturbances can be identified and used to improve the response of the rear suspension. The performance of the vehicle with neuro-control and with LQ control are compared.
TL;DR: In this paper, a system incorporating feedforward plus feedback control was configured such that it would follow the target yaw rate found by calculation, and selection of optimum values for the control system constants made it possible to separate control of the steering input response characteristic from control of vehicle stability against external disturbances.
Abstract: SUMMARY A system incorporating feedforward plus feedback control was configured such that it would follow the target yaw rate found by calculation. Selection of optimum values for the control system constants made it possible to separate control of the steering input response characteristic from control of vehicle stability against external disturbances. The former is controlled by the feedforward control function and the latter by the feedback control function; the values of the two functions can be set independently.
TL;DR: In this paper, the authors discuss the integration of chassis and Traction Control systems, what is possible, what makes sense, and what is under development in VANETs.
Abstract: (1993). Integration of Chassis and Traction Control Systems What is Possible – What makes Sense – What is under Development* Vehicle System Dynamics: Vol. 22, No. 5-6, pp. 283-298.
TL;DR: In this paper, the attitude and vibration control of a passenger car on the basis of a full vehicle model is discussed. And the attitude control using semi-actively generated compensation forces prevents the car from rolling in curves and pitching during braking or accelerating.
Abstract: SUMMARY The paper discusses the attitude and vibration control of a passenger car on the basis of a full vehicle model. The analysis presented consists of two parts: (I) The introduction of a newly developed semi-active anti-roll/pitch system, (ii) An example of an actively suspended full vehicle model using a simple control strategy to improve ride comfort. The attitude control using semi-actively generated compensation forces prevents the car from rolling in curves and pitching during braking or accelerating. The strength of the system is the small energy consumption. The performance of the combination of both attitude and vibration control can compete with a fully active suspension system.
TL;DR: In this paper, new control methods for the active suspension are described for improving ride comfort further, and a preview control rule is proposed for improving stability further, roll stiffness distribution control is examined by the test vehicle.
Abstract: SUMMARY This paper describes new control methods for the active suspension. For improving ride comfort further, preview control rule is proposed. For improving stability further, roll stiffness distribution control rule is examined by the test vehicle. Simulations and vehicle driving tests are conducted to confirm the effect of these new control methods. The results of simulations and vehicle driving tests show in our research phase that preview control can achieve a substantial improvement in ride comfort and application of roll stiffness distribution control provides a large improvement in stability
TL;DR: The simulation of the IAVSD Road Vehicle Benchmark Bombardier Iltis with FASIM, MEDYNA, NEWEUL and SIMPACK is described in this article.
Abstract: (1993). Simulation of the IAVSD Road Vehicle Benchmark Bombardier Iltis with FASIM, MEDYNA, NEWEUL and SIMPACK. Vehicle System Dynamics: Vol. 22, No. sup1, pp. 215-253.
TL;DR: In this article, the kinematic and dynamic behaviors of a five-link suspension unit were investigated, where the movement of the wheel carrier is constrained by five rods with spherical joints at both ends.
Abstract: The problem concerns the kinematic and dynamic behaviours of a five- link suspension unit. The movement of the wheel carrier is constrained by five rods with spherical joints at both ends, so that the overall mechanism has two degrees of freedom: suspension movement of the wheel carrier, and rotation of the wheel. In order to treat the benchmark problem, it was necessary to implement a module for the five-link suspension in the computer program FASIM. For the covering abstract see IRRD 860691.
TL;DR: In this paper, it is shown how the driver adapts himself to the vehicle and which technical parameters may effect this adaptation, which is exactly the other way round as it was originally thought.
Abstract: SUMMARY In order to minimize accidents and achieve comfortable handling it is necessary to analyse the control behaviour of the driver-vehicle system and adapt the vehicle to the driver. However, most of the tests have shown, that under normal driving conditions the driver adapts himself to the vehicle, which is exactly the other way round as it was originally thought. In this paper it would be shown, how the driver adapts himself to the vehicle and which technical parameters may effect this adaptation.
TL;DR: In this paper, an adaptive control system of the model following type is proposed for drive motion control of a four wheel steering car with using neural network (NN) which has mastered nonlinear friction force between tire and road surface.
Abstract: SUMMARY An adaptive control system of the model following type is proposed for drive motion control of a four wheel steering (4WS) car with using neural network (NN) which has mastered nonlinear friction force between tire and road surface. A model of one rigid body is adopted which represents appropriately two kinds of car motion caused by steering action, namely the lateral displacement and the yawing rotation, and an equation of motion is described in a simplified form to make a system equation for motion control possible. Nonlinear relation between the cornering force of tire and the slip angle is obtained by numerical analysis with the tire model proposed by E. Fiala, taking friction coefficient and car speed as the parameters. The result is used as the teaching signal for NN. Three NN are used in the control system composed of both the feed-forward and the feedback circuits in order to realize adaptive control. Validity and usefulness of the proposed adaptive control system with NN are verified by t...
TL;DR: In this paper, the A'GEM multibody dynamics package is presented. But it is limited to a single vehicle and cannot be used in a multi-modal vehicle system.
Abstract: (1993). The A'GEM Multibody Dynamics Package. Vehicle System Dynamics: Vol. 22, No. sup1, pp. 41-44.
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TL;DR: In this article, the main features of the AUTODYN and ROBOTRAN programs are introduced, which allow to derive the equations of motion of mechanical systems which can be represented by a set of rigid bodies interconnected by joints, and are used for various dynamical analysis such as numerical integration, equilibrium determination, numerical linearization, eigenvalue determination and stability analysis.
Abstract: This presentation introduces the main features of the AUTODYN and ROBOTRAN programmes [1]. These programmes, based on d'Alembert Potential Power Principle, allow to derive the equations of motion of mechanical systems which can be represented by a set of rigid bodies interconnected by joints. These results are used for various dynamical analysis such as numerical integration, equilibrium determination, numerical linearization, eigenvalue determination and stability analysis. In particular, they have important applications in the fields of vehicle dynamics and robotics