Author
J.D. Robson
Bio: J.D. Robson is an academic researcher from University of Glasgow. The author has contributed to research in topics: Random vibration & Stochastic process. The author has an hindex of 6, co-authored 15 publications receiving 922 citations.
Papers
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TL;DR: It is shown that typical road surfaces may be considered as realizations of homogeneous and isotropic two-dimensional Gaussian random processes, and a single direct spectral density function provides a road surface description which is sufficient for multi-track vehicle response analysis.
586 citations
Journal Article•
TL;DR: In this paper, the authors investigated the response of a vehicle to traversal of a road surface described by means of the concepts of random process theory, and developed a relevant response theory, first in terms of a four-variate excitation and then in terms with the possible simplifying assumptions.
Abstract: The paper is concerned with the determination of vehicle response due to traversal of a road surface described by means of the concepts of random process theory. The relevant response theory is developed, first, in terms of a four-variate excitation and then in terms of the possible simplifying assumptions. The relationship between excitation and the road profile is explained. Roads are described in terms of single profiles, profile pairs and then, using the concept of isotropy, complete surfaces. The validity of the isotropic hypothesis is considered.
189 citations
TL;DR: In this paper, the authors proposed a road surface model based on the assumption of isotropy and showed that a particular profile spectral density can be used to define an effective surface model, and validated the proposed model by comparison with coherencies based on measurement.
67 citations
TL;DR: In this article, a new spectral description f(n) is expressed in terms of the profile spectral density S(n), which provides essential admissibility criteria for proposed forms of S n and is shown that some simple idealized profile descriptions are inadmissible.
44 citations
TL;DR: In this paper, the stationary response of a travelling system to profile-imposed excitation is investigated and the system is treated as linear and both the profile and traversal velocity of the system are considered to be stationary and Gaussian random functions of horizontal distance.
33 citations
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TL;DR: In this article, the central limit theorem is invoked to show that the variance of the height distribution of a structure is linearly related to the length of sample involved, and this relationship is shown to agree well with measurements taken over many scales of size, and from throughout the physical universe.
Abstract: TOPOGRAPHY is often considered as a narrow bandwidth of features covering the form or shape of the surface. After detailed study of many measurements we consider that as well as the possibility of a dominant range of features there is always an underlying random structure where undulations in surface height continue over as broad a bandwidth as the surface size will allow. We consider this a result of many physical effects each confined to a specific waveband but no band being dominant. We invoke the central limit theorem and show through Gaussian statistics that the variance of the height distribution of such a structure is linearly related to the length of sample involved. In another form, the power spectral density, this relationship is shown to agree well with measurements of structures taken over many scales of size, and from throughout the physical universe.
634 citations
TL;DR: In this article, a comparative study of several simple passive suspension struts, each containing at most one damper and inerter as a preliminary investigation into the potential performance advantages of the element is made.
Abstract: A new ideal mechanical one-port network element named the inerter was recently introduced, and shown to be realisable, with the property that the applied force is proportional to the relative acceleration across the element. This paper makes a comparative study of several simple passive suspension struts, each containing at most one damper and inerter as a preliminary investigation into the potential performance advantages of the element. Improved performance for several different measures in a quarter-car model is demonstrated here in comparison with a conventional passive suspension strut. A study of a full-car model is also undertaken where performance improvements are also shown in comparison to conventional passive suspension struts. A prototype inerter has been built and tested. Experimental results are presented which demonstrate a characteristic phase advance property which cannot be achieved with conventional passive struts consisting of springs and dampers only.
377 citations
TL;DR: In this paper, a review of the literature relating to the design of automobile suspension systems for ride comfort and control of wheel load variations for frequencies below body structure resonances is reviewed.
Abstract: SUMMARY Based mainly on English language literature, information relating to the design of automobile suspension systems for ride comfort and control of wheel load variations for frequencies below body structure resonances is reviewed. The information is interpreted in the context of vehicles which travel through a wide speed range on roads of markedly differing quality, which do so carrying different loads and which are required to possess good handling qualities. Sections are devoted to describing road surfaces, modelling vehicles and setting up performance criteria, and to passive, active, semi-active and slow-active system types. Methods for deriving active system control laws are outlined. Strengths and weaknesses of the various systems are identified and their relative performance capabilities and equipment requirements are discussed. Attention is given to adaptation of the suspension or control system parameters to changing conditions. Remaining research needs are considered.
344 citations
TL;DR: In this article, the authors compared numerical results and some analytical prediction formulae available for fatigue damage evaluation; amongst all expressions, a new proposed original approach was shown to give sound theoretical framework and improved results.
295 citations
TL;DR: In this paper, a road adaptive modified skyhook control for the semi-active Macpherson strut suspension system of hydraulic type is investigated, which incorporates the rotational motion of the unsprung mass.
Abstract: In this paper, a road adaptive modified skyhook control for the semi-active Macpherson strut suspension system of hydraulic type is investigated. A new control-oriented model, which incorporates the rotational motion of the unsprung mass, is introduced. The control law extends the conventional skyhook-groundhook control scheme and schedules its gains for various road conditions. Using the vertical acceleration data measured, the road conditions are estimated by using the linearized new model developed. Two filters for estimating the absolute velocity of the sprung mass and the relative velocity in the rattle space are also designed. The hydraulic semi-active actuator dynamics are incorporated in the hardware-in-the-loop tuning stage of the control algorithm developed. The optimal gains for the ISO road classes are discussed. Experimental results are included. @DOI: 10.1115/1.1434265#
245 citations