C G Giles

Bio: C G Giles is an academic researcher. The author has contributed to research in topics: Deflection (engineering) & Dynamic loading. The author has an hindex of 1, co-authored 1 publications receiving 19 citations.

Static and dynamic stiffness and deflection mode measurements on a motorcycle, with particular reference to steering behaviour

Abstract: A comparison between two different methods of determining the stiffness of a motorcycle frame is made. The first employs conventional, static loading of the frame with deflections and mode shape measured by dial gauges. The second entails dynamic loading of the frame by means of a sinusoidally driven shaker with deflections obtained by means of an accelerometer, electronic data processing then yielding frequency response information. Conclusions are drawn about the implications for accurate modelling of motorcycle steering behaviour arising from differences between the static and dynamic properties of the frame.

Advances in the modelling of motorcycle dynamics

Abstract: Starting from an existing advanced motorcycle dynamics model, which allows simulation of reasonably general motions and stability, modal and response computations for small perturbations from any trim condition, improvements are described. These concern (a) tyre/road contact geometry, (b) tyre shear force and moment descriptions, as functions of load, slip and camber, (c) tyre relax- ation properties, (d) a new analytic treatment of the monoshock rear suspension mechanism with sample results, (e) parameter values describing a contemporary high performance machine and rider, (f) steady-state equilibrium and power checking and (g) steering control. In particular, the "Magic Formula" motorcycle tyre model is utilised and complete sets of parameter values for contemporary tyres are derived by identification methods. The new model is used for steady turning, stability, design parameter sensitivity and response to road forcing calculations. The results show the predictions of the model to be in general agreement with observations of motorcycle behaviour from the field and they suggest that frame flexibility remains an important design and analysis area, despite improvements in frame designs over recent years. Motorcycle rider parameters have significant influences on the behaviour, with results consistent with a commonly held view, that lightweight riders are more likely to suffer oscillation problems than heavyweight ones.

Bicycles, motorcycles, and models

Abstract: The development of bicycles and motorcycles since the first patented running machine, or draisine, in 1817 is described. Bicycle modeling and control were also discussed. These models include: derivatives or simplifications of Whipple's bicycle dynamics model in which the lateral motion constraints at the road contact are nonholonomic, requiring special techniques to form correct equations of motion; and the Timoshenko-Young model in which the steer angle and speed completely determine the lateral motion of the base point of an inverted pendulum that represents the vehicle's roll dynamics

Multibody Aspects of Motorcycle Modelling with Special Reference to Autosim

Abstract: Modelling of the ride and handling dynamics of motorcycles using the symbolic mechanical multibody system package Autosim has been carried out since 1995. Motorcycles are principally of tree structure but their geometry is complex in relation to the tyre to road contact and tyre force and moment descriptions and to the chain drive system. They may contain closed kinematic loops, according to common suspension and steering design variations. Various aspects of the modelling problem are discussed and some implications, from a multibody standpoint, of choosing different options are exposed. Simulation results illustrate the “antisquat” behaviour of a chain drive transmission and the “anti-dive” behaviour of a Telelever front suspension system.

The influence of frame compliance and rider mobility on the scooter stability

Abstract: This article investigates the effect of frame compliance and rider mobility on the scooter stability Particular attention is given to the wobble mode, because it may easily become unstable in the vehicle speed range This article includes a synthetic discussion of previous works, presents a new mathematical model, and discusses the results of both numerical and experimental analyses of the vehicle stability by varying the vehicle characteristics and motion conditions The mathematical model describes the out-of-plane dynamics of the scooter and consists of a twelve-degree-freedom linear model It describes the main scooter features and, in particular, includes the frame compliance, rider mobility, and an advanced tire model The torsion and bending compliance of both the front fork and swingarm are modelled using lumped rotational springs; similarly, the rider mobility is described by means of two soft springs which connect the rider body to the chassis The tire model describes in detail the carcass geo

On steering wobble oscillations of motorcycles

Abstract: The paper is aimed at an improved understanding of steering wobble oscillations of motorcycles through simulation. The background to the problem is discussed first. Then, an existing mathem...