An Automatic Speed Control System of a Treadmill with Ultrasonic Sensors

초음파 센서를 이용한 트레드밀의 자동속도 제어시스템

  • 마누룽 오라리우스 (경상대학교 기계항공공학부 항공기부품기술연구센터) ;
  • 윤정원 (경상대학교 기계항공공학부 항공기부품기술연구센터)
  • Received : 2010.12.17
  • Accepted : 2011.03.27
  • Published : 2011.05.01


In this paper, we have developed an automatic velocity control system of a small-sized commercial treadmill (belt length of 1.2 m and width of 0.5 m) which is widely used at home and health centers. The control objective is to automatically adjust the treadmill velocity so that the subject's position is maintained within the track when the subject walks at a variable velocity. The subject's position with respect to a reference point is measured by a low-cost sonar sensor located on the back of the subject. Based on an encoder sensor measurement at the treadmill motor, a state feedback control algorithm with Kalman filter was implemented to determine the velocity of the treadmill. In order to reduce the unnatural inertia force felt by the subject, a predefined acceleration limit was applied, which generated smooth velocity trajectories. The experimental results demonstrate the effectiveness of the proposed method in providing successful velocity changes in response to variable velocity walking without causing significant inertia force to the subject. In the pilot study with three subjects, users could change their walking velocity easily and naturally with small deviations during slow, medium, and fast walking. The proposed automatic velocity control algorithm can potentially be applied to any locomotion interface in an economical way without having to use sophisticated and expensive sensors and larger treadmills.


  1. 전자신문 2007년 2월23일자, 헬스케어로봇.
  2. S. Nam and M. Sung, "The study for treadmill exercise using virtual reality simulation program view of the physiology," The Korean Journal of Physical Education, vol. 44, no. 5, pp. 391-399, 2005.
  3. B. Novandy and J. Yoon, "Control and VR navigation of a gait rehabilitation robot with upper and lower limbs connections," Journal of Institute of Control, Robotics and Systems(in Korean), vol. 15, no. 3, pp. 315-322, Mar. 2009.
  4. J. Yoon, J. Ryu, and J. Park, "Intelligent control of a virtual walking machine for virtual reality interface," Journal of Control, Automation, and Systems Engineering(in Korean), vol. 12, no. 9, pp. 926-934, Sep. 2006.
  5. R. R. Christensen, J. M. Hollerbach, Y. Xu, and S. G. Meek, "Inertial-force feedback for the treadport locomotion interface," Presence: Teleoperators and Virtual Environments, vol. 9, pp. 1-14, 2000.
  6. J. Zitzewitz, M. ichael Bernhardt, and R. Riener, "A novel method for automatic treadmill speed adaptation," IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 15, no. 3, 2007.
  7. A. Koenig, C. Binder, J. von Zitzewitz, X. Omlin, M. Bolliger, and R. Riener, "Voluntary gait speed adaptation for robotassisted treadmill training," IEEE 11th Int. Conf. on Rehabilitation Robotics, Japan, Jun. 2009.
  8. M. G. Farnet, "Treadmill having an automatic speed control system," U.S. Patent 5 368 532, Nov. 1994.
  9. L. Lichtenstein, J. Barabas, R. L. Woods, and E. Peli, "A feedback-controlled interface for treadmill locomotion in virtual environments," ACM Transactions on Applied Perception, vol. 4, no. 1, 2007.
  10. J. L. Souman, P. R. Giordano, I. Frissen, A. D. Luca, and M. O. Ernst, "Making virtual reality real: perceptual evaluation of a new treadmill control algorithm," ACM Transaction on Applied Perception, vol.7, Feb. 2010.
  11. F. H. Durgin, K. Gigone, and R. Scott, "Perception of visual speed while moving," J. Exp. Psychol. Hum Percept. Perform., vol. 31, pp. 339-353, 2005.
  12. V. I. Utkin, "Sliding mode control design principles and application to electric drives," IEEE Trans. Industrial Electronics, vol. 40, pp. 41-49, 1993.
  13. J. E. Slotline and W. Li, Applied Nonlinear Control, Prentice Hall, 1991.
  14. H. Lee and V. I. Utkin, "Chattering suppression methods in sliding mode control systems," Annual Reviews in Control, vol. 31, pp. 179-188, 2007.
  15. K. L. Shi, T. F. Chan, Y. K. Wong, and S. L. Ho, "Speed estimation of an induction motor drive using an optimized extended Kalman filter," IEEE Trans on Industrial Electronics, vol. 49, no. 1, Feb. 2002.
  16. P. R. Belanger, "Estimation of angular velocity and acceleration from shaft encoder measurement," IEEE Int. Conf. on Robotics and Automation, France, 1992.
  17. Y. X. Shu, D. Sun, and B. Y. Duan, "Design of an enhanced nonlinear PID controller," Mechatronics, vol. 15, pp. 1005-1024, 2005.