Parameter Design of Disturbance Observer for a Robust Control of Two-Wheeled Wheelchair System
- 437 Downloads
The wheelchair system presented in this research has only two wheels. This mechanical choice increases the maneuverability of the wheelchair itself, making the system more agile and able to overcome small obstacles (e.g. step, bump, rough terrain, etc.) in different kinds of environments. In addition, the user is able to train her/his body, since it is necessary to lean the body forward and backward to drive the wheelchair along the corresponding direction. Besides these advantages, there is a big drawback: the system is naturally unstable. For this reason, a motion controller is necessary to keep the wheelchair balanced. Furthermore, it is not possible to have a direct control along the pitch direction and a stable configuration is reached only through the actuation of the wheels. In order to estimate the torque acting on the pitch direction, the synthesized pitch angle disturbance observer (SPADO) is introduced. The results collected by SPADO combined with a Lyapunov controller makes the stabilization possible. During the design phase, particular attention should be paid to the inertia parameters variation, otherwise the performance of the entire system decreases. A detailed stability analysis is carried on to identify, from a theoretical point of view, the best parameter tuning. Then, the results from the experiments on the real platform are presented to verify the theoretical results.
KeywordsTwo-wheeled wheelchair Robust motion control Disturbance observer Inverted pendulum Inertia parameters calibration Stability analysis
Unable to display preview. Download preview PDF.
- 2.Acar, C.: Advanced motion control of dynamically stabilized rwo-wheeled mobile system. Ph.D. thesis, Keio University (2011)Google Scholar
- 3.Ahmad, S., Tokhi, M.: Forward and backward motion control of wheelchair on two wheels. In: 3rd IEEE Conference on Industrial Electronics and Applications. ICIEA 2008, pp. 461–466 (2008)Google Scholar
- 4.Ahmad, S., Tokhi, M.: Modelling and control of a wheelchair on two wheels. In: Second Asia International Conference on Modeling Simulation. AICMS 08, pp. 579–584 (2008)Google Scholar
- 7.Murakami, T., Ohnishi, K.: Observer-based motion control-application to robust control and parameter identification. In: Asia-Pacific Workshop on Advances in Motion Control Proceedings, pp. 1–6 (1993)Google Scholar
- 9.Nakamura, A., Murakami, T.: A stabilization control of two wheels driven wheelchair. In: IEEE/RSJ International Conference on Intelligent Robots and Systems. IROS 2009, pp. 4863–4868 (2009)Google Scholar
- 10.Ohnishi, K.: Robust motion control by disturbance observer. J. Robot. Soc. Jpn. (1993). (in Japanese)Google Scholar
- 11.[Online]: Segway human transporter. Available: http://www.segway.com (2004)
- 14.Takahashi, Y., Tsubouchi, O.: Modern control approach for robotic wheelchair with inverse pendulum control. In: Proceedings of the 5th International Conference on Intelligent Systems Design and Applications, ISDA ’05, pp. 364–369 (2005)Google Scholar
- 16.Yun, X., Yamamoto, Y.: Internal dynamics of a wheeled mobile robot. In: Proceedings of the 1993 IEEE/RSJ International Conference on Intelligent Robots and Systems ’93, IROS ’93, vol. 2, pp. 1288–1294 (1993)Google Scholar