A Real-Time Center of Gravity Trajectory Generation of a Biped Humanoid under Variable Reference ZMP Trajectory

Abstract:

This paper describes a method for generating a center of gravity trajectory of a biped humanoid robot under variable reference ZMP trajectory. A simple inverted pendulum model (SIPM) is used to calculate a center of gravity (CoG) trajectory from a reference zero moment point (ZMP) trajectory with an analytic form, which is based on the Fourier series. Fundamentally, we used a time segmentation based approach. For each segment, we defined its duration and boundary conditions, which are the key parameters of ZMP trajectory design. After designing the ZMP trajectory in each segment, we can automatically calculate the CoG trajectory by matching the boundary conditions and by calculating the coefficients between the time segments. The reference ZMP trajectory can be changed by updating the boundary conditions during walking. We successfully verified the proposed method through full-body dynamic simulations with variable step length.

• Periodical: Applied Mechanics and Materials (Volumes 284-287)
• Pages: 1734-1738
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.284-287.1734
• Online since: January 2013
• Authors: Ill Woo Park, Baek Kyu Cho, Jung Yup Kim
• Keywords: Analytic Solution, Biped Walking, Center of Gravity, Humanoid Robot, Zero Moment Point

References

[1] Q. Huang, K. Yokoi, S. Kajita, K. Kaneko, H. Arai, N. Koyachi and K. Tanie: Planning Walking Patterns for a Biped Robot, IEEE Transactions on Robotics and Automation Vol. 17, no. 3 (2001), pp.280-289.

DOI: 10.1109/70.938385

[2] I. W. Park, J. Y. Kim, J. Lee and J. H. Oh: Online Free Walking Trajectory Generation for Biped Humanoid Robot KHR-3 (HUBO), IEEE Int. Conf. on Robotics & Automation (2006), pp.1231-1236.

DOI: 10.1109/robot.2006.1641877

[3] I. W. Park and J. Y. Kim: Fourier Series-Based Walking Pattern Generation for a Biped Humanoid Robot, IEEE-RAS International Conference on Humanoid Robots (2010), p.461–467.

DOI: 10.1109/ichr.2010.5686303

[4] T. Sugihara and Y. Nakamura: A Fast Online Gait Planning with Boundary Condition Relaxation for Humanoid Robots, IEEE Int. Conf. on Robotics & Automation (2005), pp.305-310.

DOI: 10.1109/robot.2005.1570136

[5] H. Lim, Y. Yamamoto, and A. Takanishi: Control to Realize Human-like Walking of a Biped Humanoid Robot, Int. Conf. on Systems, Man and Cybernetics (2000), pp.3271-3276.

DOI: 10.1109/icsmc.2000.886509

[6] S. Schaal: The SL simulation and real-time control software package, Technical report, University of Southern California (2004).