1. D. Reynaerts, J. Peilw and H. Brussel, Proc., Actuator 96, (1996).
2. S. Guo and Q. Pan, Proc., IEEE/RSJ International Conference on Intelligent Robots and Systems, pp.2265-2270, (2005).
3. J. Kwon, S. Park, B. Kim and J. Park, Proc., IEEE International Conference on Robotics and Automation, pp.1315-1320, (2005).
4. M. Ohno, T. Hamano and S. Kato, Journal of Robotics and Mechatoronics, Vol. 18, No. 1, pp.11-17, (2006).
5. J. Bocko, M. Kelemen, T. Kelemenova and J. Jezny, Bulletin of applied mechanics, Vol. 5, No. 18, pp.34-36, (2009).