An Experimental Study on Brake Judder via the Frequency Analysis of the Brake System and Vehicle System of a Commercial Vehicle

상용차량의 브레이크 시스템과 차량 시스템 주파수 분석을 통한 브레이크 저더의 실험적 고찰

  • 문일동 (현대-기아자동차(주) 상용선행개발팀) ;
  • 김종대 (전북대학교 대학원) ;
  • 오재윤 (전북대학교 기계항공시스템공학부 자동차신기술연구소)
  • Published : 2007.12.01


This paper studies experimentally on the building-up process for the amplitude of a commercial truck vibration induced by brake judder. A front axle drum equipped with a drum brake system is utilized for this experiment. A brake dynamo test, a real vehicle ride test and a real vehicle braking test are performed for the analysis of brake judder. The brake dynamo test measures judder by applying brake chamber pressures of 1, 2 and 3 bar at initial brake pad temperatures of $100^{\circ}C$ and $150^{\circ}C$. In order to assess the vertical acceleration at the front axle, the real vehicle ride test on a straight test road with velocities of 20, 40, 60 and 80 km/h is performed. The real vehicle braking test is carried out at the deceleration rate of 0.2g from a velocity of 90km/h for evaluating the vertical, lateral and longitudinal accelerations both at the front axle and at the cab floor under the driver's seat. The magnitudes and frequencies of the measured peak accelerations from the brake dynamo test, the real vehicle ride test and the real vehicle braking test are comparatively analyzed. This paper shows that the vibration produced by brake judder is built up due to the brake system's peak acceleration frequency being close to the vehicle ride mode's frequency.


Brake Dynamometer Test;Brake System;Commercial Vehicle;Drum Brake;Frequency Analysis;Brake judder;Unsprung Mass


  1. Abdelhamid, M. K., 1997, 'Brake Judder Analysis: Case Studies,' SAE 972027
  2. Gassmann, S. and Engel, H. G., 1993, 'Excitation and Transfer Mechanism of Brake Judder,' SAE 931880
  3. Youn, S. W. and Han, M. C., 1997, 'Study on Brake Judder Caused by Disc Run-out and Disc Thickness Variation,' Trans. of KSAE, Vol. 7, No.2, pp. 378-386
  4. Lee,K. S., Suh, K. H.,Kuk, J.Y andChyun, LB., 1999, 'Analytical Study in Brake Judder Reduction of Medium Bus,' Trans. of KSAE, Vol. 9, No.4, pp. 148-156
  5. Hwang, I. J. and Park, G.J., 2005, 'System Mode and Sensitivity Analysis for Brake Judder Reduction,' Trans. of KSAE, Vol. 13,No.6, pp. 142-153

Cited by

  1. Squeal Test Using Lab-Scale Brake Dynamometer for Pad Angle and Negative-slope vol.14, pp.7, 2013,