This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
The Challenge of Designing a Semiactive Damper for Heavy Truck Seat Suspensions
Technical Paper
2005-01-3544
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
The close proximity of seat suspensions to human body presents several challenges in terms of the perception of the suspension forces by the vehicle operator. This is particularly true of the suspensions with time-varying forces, such as semiactive seat suspensions. The major challenge in such suspensions is changing the suspension force from one state to under, without causing excessive amounts of dynamic jerk. This paper looks into the cause of dynamic jerk in semiactive suspensions with skyhook control, and presents two alternative implementations of skyhook control, called “no-jerk skyhook,” and “skyhook function,” for the purpose of this study. An analysis of the relationship between absolute velocity of the sprung mass and the relative velocity across the suspension is used to show the damping force discontinuities that result from skyhook control. This analysis shows that at relative velocity zero crossings, skyhook control introduces a sharp increase (jump) in damping force, which, in turn, causes a jump in sprung mass acceleration. This acceleration jump, or jerk, causes a significant reduction in isolation benefits that is offered by skyhook suspensions. The alternative implementations of skyhook control considered in this study offer modifications to the formulation of conventional skyhook control such that the damping force jumps are eliminated. The alternative policies are compared with skyhook control, using a laboratory implementation of a heavy truck seat suspension with base excitation in vertical direction. An evaluation of the damping force, seat acceleration, and the electrical current to the magneto-rheological (MR) seat damper shows that the alternative implementations of skyhook control can entirely eliminate the damping force discontinuities and the resulting dynamic jerks caused by skyhook control.
Recommended Content
Authors
Citation
Ahmadian, M., "The Challenge of Designing a Semiactive Damper for Heavy Truck Seat Suspensions," SAE Technical Paper 2005-01-3544, 2005, https://doi.org/10.4271/2005-01-3544.Also In
References
- Karnopp, D. C. Cosby, M. J. 1974 “System for controlling the transmission of energy between spaced members,”
- Crosby, M. J. Karnopp, D. C. 1973 “The active damper,” The Shock and Vibrations Bulletin 43 Naval Research Laboratory Washington, DC
- Ivers, D. E. Miller, L. R. 1991 “Semiactive suspension technology: An evolutionary view,” ASME Advanced Automotive Technologies 1991 327 346
- Elbeheiry, E. M. Karnopp, D. C. Elaraby, M. E. Abdelraaouf, A. M. “Advanced Ground Vehicle Suspension Systems - A Classified Bibliography,” Vehicle System Dynamics 231 258 24 1995
- Goncalves, F. D. Ahmadian, M. “A Hybrid Control Policy for Semiactive Vehicle Suspensions,” Shock and Vibration 10 1 January 2003 59 69
- Koo J. H. Ahmadian M. Setareh M. Murray T. “In Search of Suitable Control Methods for Semi-Active Tuned Vibration Absorbers,” Journal of Vibration and Control 10 2 February 2004 163 174
- Ahmadian, M. Reichert, B. A. Song, X. “System Nonlinearities Induced by Skyhook Dampers,” Shock and Vibration 8 2 August 2001 95 104