An approximate stance map of the spring mass hopper with gravity correction for nonsymmetric locomotions

Date
2009
Advisor
Instructor
Source Title
2009 IEEE International Conference on Robotics and Automation
Print ISSN
1050-4729
Electronic ISSN
Publisher
IEEE
Volume
Issue
Pages
2388 - 2393
Language
English
Type
Conference Paper
Journal Title
Journal ISSN
Volume Title
Abstract

The Spring-Loaded Inverted Pendulum (SLIP) model has long been established as an effective and accurate descriptive model for running animals of widely differing sizes and morphologies, while also serving as a basis for several hopping robot designs. Further research on this model led to the discovery of several analytic approximations to its normally nonintegrable dynamics. However, these approximations mostly focus on steady-state running with symmetric trajectories due to their linearization of gravitational effects, an assumption that is quickly violated for locomotion on more complex terrain wherein transient, non-symmetric trajectories dominate. In this paper, we introduce a novel gravity correction scheme that extends on one of the more recent analytic approximations to the SLIP dynamics and achieves good accuracy even for highly non-symmetric trajectories. Our approach is based on incorporating the total effect of gravity on the angular momentum throughout a single stance phase and allows us to preserve the analytic simplicity of the approximation to support our longer term research on reactive footstep planning for dynamic legged locomotion. We compare the performance of our method in simulation to two other existing analytic approximations and show that it outperforms them for most physically realistic non-symmetric SLIP trajectories while maintaining the same accuracy for symmetric trajectories. © 2009 IEEE.

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Keywords
Analytic approximation, Complex terrains, Correction schemes, Descriptive Model, Footstep planning, Hopping robots, Legged locomotion, Nonsymmetric, Slip dynamics, Spring loaded inverted pendulums, Spring mass, Stance phase, Total effect, Animals, Biped locomotion, Infrared detectors, Machine design, Robotics, Robots, Trajectories
Citation
Published Version (Please cite this version)