Essential Criteria for Handling Measurement of a Ground

Topics: Steering, Vehicle dynamics, Caster angle Pages: 14 (4491 words) Published: September 25, 2010
Introducing Essential Criteria for Handling Measurement of a Ground Vehicle Ehsan G. Naeini, Hassan Sayyaadi2, Mahmoud Saadat3

1Master of Science, Sharif University of Technology; 2Proffessor Associate, Sharif University of Technology; 3Proffessor Assistant, Sharif University of Technology;

Handling behavior of a ground vehicle is one of main properties of a vehicle that play an important role in technical and commercial evaluation of a vehicle. The frequency weighted mean square value of the vertical acceleration is a well-known criterion for ride comfort. For handling, several criteria have been put forward, which are to a more or lesser extent dependent on driver input and each car company select some of these criteria as major criteria for their design, with attention to car application, consumption bazaar, environment and road condition. Off-road test is one of the best choices for handling quality evaluation of a vehicle, in which some properties of vehicle are measured by diverse sensors that fixed on vehicle. Resultant of these sensor's data and professional driver's opinion is good criterion in handling evaluation. In this work we performed some objective steady state tests (CRC) and objective transient tests (impulse steering input) on five most common vehicles in Iran and recorded different sensor's outputs and obtained some quantities. Also we performed some subjective test with professional drivers and their opinions about handling quality were recorded with scores between 1 and 20. Then we will introduce 3 criteria, side slip angle and roll angle and time lag between steering input and lateral acceleration as most essential criteria in handling measurement, and then we will show a good agreement between categorizing these five vehicles according to each these 3 criteria and categorizing them according to drivers’ scores.

Keywords: Handling Criteria, Roll Angle, Slip Angle, Steady State Test, Transient Test

The root mean square value of the vertical acceleration is known to be a good criterion of comfort, and levels of acceptance in terms of comfort and safety have been determined [1]. A single, unambiguous objective criterion for handling has however eluded the vehicle science community despite numerous studies pertaining to the topic. As Vlk [2] notes with respect to truck-trailer devices, ‘‘It is most desirable to define evaluation criteria for the handling performance of vehicle combinations, both for steady state and transient driving behavior’’. The aim of this paper is to summarize suggestions and conclusions of research on handling criteria, and to present and discuss the results of tests performed and professional drivers’ opinions to introduce the most essential handling criteria, which will be suitable for handling evaluation and can be used by vehicle companies to enhance their products quality.

Literature survey

Yaw rate and lateral acceleration:
Horiuchi et al. [3] determined that drivers focus attention on yaw angle rather than on lateral position error, Ye, for steering a two wheel steering system car. For a four wheel steering system car Ye becomes more important. Handling (steer response) is measured in terms of yaw rate and lateral acceleration for handling characteristics of four wheel active steering vehicles over a wide maneuvering range of lateral and longitudinal accelerations [4]. Sharp and Pan [5] comment that a vehicle with no body roll in general has better steering behavior than one that rolls. Handling performance could thus be improved if the vehicle is made stiffer in roll by stiffening of anti-roll bars.

Roll angle:
Metrics used in subjective/objective driver-handling correlations for J-turns (step steer input) by Crolla et al. [6] include: peak lateral acceleration response time, peak road wheel steer angle and response time, peak yaw and roll rate and response...

References: [1] British Standards Institution. British Standard Guide to Measurement and Evaluation of Human Exposure to Whole Body Mechanical Vibration and Repeated Shock. BS 6841, 1987.
[5] Sharp RS, Pan D. On active control for automobiles. In: 12th IAVSD Symposium August 26–30, 1991. Suppl. to Veh. Sys. Dyn. 20.
[6] Crolla DA, Chen DC, Whitehead J P, Alstead CJ. SAE Technical Paper No. 980226, 1998.
[7] Reichardt W. Correlation analysis of open/closed loop data for objective assessment of handling characteristics of cars. SAE Technical Paper No. 910238, 1991.
[8] National Highway Safety Administration, 2000. Roll over prevention Docket No. NHTSA-2000-6859 RIN 2127-AC64.Availablefrom: Accessed September 2002.
[11] Dahlberg E. A method determining the dynamic roll over threshold of commercial vehicles. SAE paper 2000-01-3492. 2000.
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