Planar Dynamics of a Motorcycle: Influence of Vibration Isolation System Nonlinearity

This paper investigates the influence of the nonlinearities of a vibration isolation system on the planar dynamics of a motorcycle. The use of a nonlinear isolation system is often necessitated by design and packaging constraints. Although the use of a vibration isolation system is uncommon in motorcycles, it is used in some cases to enhance ride comfort by mitigating vibrations transmitted to the rider due to shaking forces. In such cases, the handling of the motorcycle can be influenced due to the coupled dynamics of the rear unsprung mass and the swing arm. In this paper, a stochastic analysis has been performed by using the statistical linearization method to specifically examine nonlinearities associated with the vibration isolation system. An eight degree-of-freedom planar model has been developed, and each isolator is represented by a modified multi-axial Kelvin-Voigt model. It has been observed that the model developed in this study can capture the coupled dynamics between the rear suspension and the vibration isolation system. Results indicate that the nonlinear design of the vibration isolation system can be useful in enhancing ride comfort in the lower frequency range without an adverse impact on handling. Furthermore, it has been observed that the parameters associated with the nonlinear vibration isolation system can be tuned to enhance ride comfort while meeting the design requirements of spatial dynamics.

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Influence of a Vibration Isolation System on Planar Dynamics of a Motorcycle

10.20855/ijav.2020.25.11603 ◽

2020 ◽

Vol 25 (1) ◽

pp. 96-103

Author(s):

Sudhir Kaul

Keyword(s):

Simple Model ◽

Design Process ◽

Dynamic Characteristics ◽

Vibration Isolation ◽

Ride Comfort ◽

Isolation System ◽

Vibration Isolation System ◽

Natural Modes ◽

The Impact ◽

Unsprung Mass

This paper examines a model to investigate the impact of a vibration isolation system on the planar (in-plane) dynamics of a motorcycle. While it is not very common, a vibration isolation system is used in some motorcycles to mitigate vibrations resulting from the shaking forces of the engine. For such layouts, the powertrain is assembled to the frame through the vibration isolation system that typically consists of two to four isolators. It is critical to comprehend the influence of the isolation system on the overall dynamic characteristics of the motorcycle due to the coupled dynamics of the rear suspension, the isolation system, and the rear unsprung mass. The influence of a vibration isolation system on the in-plane dynamics is analysed by using a relatively simple model that has been developed in this study. This model has been used to evaluate the influence of the isolation system on natural modes, transmissibility, and ride comfort. Results indicate that the use of a vibration isolation system couples the rear unsprung hop to the pitch motion of the powertrain with a slight increase in the corresponding natural frequency. Results indicate that the use of a vibration isolation system directly affects handling of the motorcycle. Furthermore, results indicate that the pitch of the sprung mass and the hop of the rear unsprung mass are particularly influenced by the vibration isolation system. The model presented in this paper could be useful in the early stages of the design process to compare the rigidly mounted powertrain to different layouts of the vibration isolation system.

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Study on Ambulance Stretcher Vibration Isolation System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.226-228.324 ◽

2012 ◽

Vol 226-228 ◽

pp. 324-327 ◽

Cited By ~ 1

Author(s):

Gong Yu Pan ◽

Ying Zhang

Keyword(s):

High Speed ◽

Vibration Isolation ◽

Ride Comfort ◽

Angular Acceleration ◽

Mathematic Model ◽

Vertical Acceleration ◽

Active System ◽

Linear Quadratic ◽

Isolation System ◽

Vibration Isolation System

The ride comfort is one of the most important performances of the ambulance. In order to avoid patients' illness or injury to deteriorate during the transportation, the ambulance is required to hold smooth motion and high speed. Therefore, it is necessary to develop stretcher vibration isolation system to improve ambulance ride comfort. In this paper, a mathematic model of six degree freedom ambulance-stretcher-occupant system is established. Based on the theory of linear quadratic optimal control, the linear quadratic regulator (LQR) controller of active ambulance stretcher is designed. The simulation results indicate that the active system equipped with the optimal controller has better vibration reduction perfomance on vertical acceleration and pitch angular acceleration of the ambulance stretcher.

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Connection of a Scanning Tunneling Microscope with a Molecular Beam Epitaxy Chamber and Analysis of the Vibration Isolation System

Journal de Physique III ◽

10.1051/jp3:1995231 ◽

1995 ◽

Vol 5 (11) ◽

pp. 1871-1885 ◽

Cited By ~ 3

Author(s):

P. Krapf ◽

J.P. Lainé(*) ◽

Y. Robach ◽

L. Porte

Keyword(s):

Molecular Beam Epitaxy ◽

Scanning Tunneling Microscope ◽

Molecular Beam ◽

Vibration Isolation ◽

Scanning Tunneling ◽

Isolation System ◽

Vibration Isolation System ◽

Tunneling Microscope ◽

Molecular Beam Epitaxy Chamber

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Characterization of force factor on voice coil actuator for active vibration isolation system

10.1063/5.0051555 ◽

2021 ◽

Author(s):

Muhajir Ab. Rahim

Keyword(s):

Vibration Isolation ◽

Force Factor ◽

Isolation System ◽

Vibration Isolation System ◽

Active Vibration ◽

Active Vibration Isolation ◽

Voice Coil Actuator

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Design and analysis of a vibration isolation system with cam–roller–spring–rod mechanism

Journal of Vibration and Control ◽

10.1177/10775463211000516 ◽

2021 ◽

pp. 107754632110005

Author(s):

Yonglei Zhang ◽

Guo Wei ◽

Hao Wen ◽

Dongping Jin ◽

Haiyan Hu

Keyword(s):

Vibration Isolation ◽

Dynamic Stiffness ◽

Experimental Studies ◽

Excitation Amplitude ◽

Isolation System ◽

Vibration Isolation System ◽

Stiffness Characteristic ◽

Negative Stiffness Mechanism ◽

Isolation Systems ◽

Vibration Isolation Performance

The vibration isolation system using a pair of oblique springs or a spring-rod mechanism as a negative stiffness mechanism exhibits a high-static low-dynamic stiffness characteristic and a nonlinear jump phenomenon when the system damping is light and the excitation amplitude is large. It is possible to remove the jump via adjusting the end trajectories of the above springs or rods. To realize this idea, the article presents a vibration isolation system with a cam–roller–spring–rod mechanism and gives the detailed numerical and experimental studies on the effects of the above mechanism on the vibration isolation performance. The comparative studies demonstrate that the vibration isolation system proposed works well and outperforms some other vibration isolation systems.

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