£>: ^ ........... ,._ ?'.;& & v, SN \z ,JJ / ai Paul W. Claar II and Wesley F. Buchele Iowa State Univ. Pradip N. Sheth ASIis-ChalmersCorp. International Off-Highway Meeting and Exposition MECCA, Milwaukee September 8-11, 1980 f -i^o* -V ?&* 75th ^fitftS^' anniversary L \.^° sim^: Downloaded from SAE International by University of Wisconsin - Madison , Monday, September 10, 2018The appearance of the code at the bottom of She first page of this paper indicates SAE's consent that copies of the paper may be made for persona! or interne! use, or for the personal or internal use of specific clients. This consent is given on the con­ dition, however, that the copier pay She stated per article copy fee through the Copyright Clearance Center, Inc., Operations Center, P.O. Box 765, Schenectady, N.Y. 12301, for copying beyond that permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale. Papers published prior to 1978 may also be copied at a per paper fee of S2.50 under the above stated conditions. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Order Department. To obtain quantity reprint rates, permission to reprint a technical paper or per­ mission to use copyrighted SAE publications in other works, contact the SAE Publications Division. ISSN 0148-7191 Copyright © 1980 Society of Automotive Engineers, Inc. Downloaded from SAE International by University of Wisconsin - Madison , Monday, September 10, 2018801023 Paul W. Claar II and Wesley F. Buchele Iowa State Univ. Pradip N. Sheth Allis-ChalmersCorp. THE OFF-ROAD VEHICLE - e.g., agricultural wheel tractor or rubber-tired earthmoving scraper, is designed to provide for a pre­ determined drawbar pull and tractive effort. With the increased speed, size, and power out­ put of these vehicles, the operator has been subjected to increasing levels of shock and vibration from the terrain and the attached implements. To reduce operator fatigue from shock and vibration, Ergonoraic considerations have become an important design criteria for vehicle development, and while these improve­ ments - e.g., operator platform and controls, and seat suspensions, help in operator con­ venience and comfort, further development is needed to extend the productivity of man- machine combination. The primary challenge in this development is to achieve the con­ flicting design goals of reduced transmitted vibration to the operator while keeping the relative motion between the operator and the control devices to an acceptable minimum. To design an off-road vehicle along basic automo­ tive theory becomes difficult because the vehicle must provide the base support for the implement in order to regulate the implement depth and level during its operation and to control the implement position during the transport mode. The first objective of this paper is to discuss the design parameters and research activities to improve the ride comfort and the dynamic behavior for increased vehicle produc­ tivity during the past twenty-five years by American and European universities and research institutes, and agricultural and earthmoving equipment manufacturers. The second objective is to review recently available dynamic model­ ing and computer simulation tools for evaluating the effect of design changes on off-road vehicle ride characteristics, in particular for an agricultural wheel tractor. DESIGN CONSIDERATION FOR OFF-ROAD VEHICLE RIDE COMFORT To increase the travel speed of an off-road vehicle and to reduce the vibration, the dy- ABSTRACT European and American suspension systems are described for improving the operator ride comfort on off-road vehicles. Analytical methods are