A method for the calculation of the effective Center of Mass of humanoid robots

In this paper we present a general strategy for the calculation of the effective Center of Mass (CoM) of humanoid robots, allowing the reduction of the error between the virtual robot model and the real platform. The method is based on an algorithm that calculates the real position of the CoM of a biped humanoid robot using only 2 force/torque sensors located on the feet of the robot. By means of this algorithm, it is possible to reduce the gap between the real and the virtual posture of the robot and consequently the errors between the ZMP trajectory calculated by the offline pattern generator and the ZMP trajectory calculated by the real-time pattern generator of the humanoid robot. Thus, the influence of the real-time control in the static and dynamic balance of a humanoid platform is minimized. Experimental results using SABIAN platform are provided to validate the proposed method. The results support the applicability of the method to more complex systems.

[1]  Eiichi Yoshida,et al.  On humanoid motion optimization , 2007, 2007 7th IEEE-RAS International Conference on Humanoid Robots.

[2]  Jun-Ho Oh,et al.  Adjustment of home posture of a biped humanoid robot using an inertial sensor and force torque sensors , 2007, 2007 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[3]  O. Stasse,et al.  Inertial Forces Posture Control for Humanoid Robots Locomotion , 2007 .

[4]  Atsuo Takanishi,et al.  Development of a bipedal humanoid robot-control method of whole body cooperative dynamic biped walking , 1999, Proceedings 1999 IEEE International Conference on Robotics and Automation (Cat. No.99CH36288C).

[5]  Atsuo Takanishi,et al.  Online walking pattern generation for biped humanoid robot with trunk , 2002, Proceedings 2002 IEEE International Conference on Robotics and Automation (Cat. No.02CH37292).

[6]  Atsuo Takanishi,et al.  Biped walking robots created at Waseda University: WL and WABIAN family , 2007, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[7]  Atsuo Takanishi,et al.  Development of a human-like walking robot having two 7-DOF legs and a 2-DOF waist , 2004, IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004.

[8]  Atsuo Kawamura,et al.  A study on the zero moment point measurement for biped walking robots , 2002, 7th International Workshop on Advanced Motion Control. Proceedings (Cat. No.02TH8623).

[9]  Atsuo Takanishi,et al.  Development of a new humanoid robot WABIAN-2 , 2006, Proceedings 2006 IEEE International Conference on Robotics and Automation, 2006. ICRA 2006..

[10]  Miomir Vukobratovic,et al.  Zero-Moment Point - Thirty Five Years of its Life , 2004, Int. J. Humanoid Robotics.

[11]  Yonghwan Oh,et al.  Estimation of the center of mass of humanoid robot , 2007, 2007 International Conference on Control, Automation and Systems.

[12]  E. Yoshida,et al.  Optimizing Humanoid Motions Using Recursive Dynamics and Lie Groups , 2008, 2008 3rd International Conference on Information and Communication Technologies: From Theory to Applications.