Departmental Papers (ESE)


We report on a continuous-time rigid-body pose estimator for a walking hexapod robot. Assuming at least three legs remain in ground contact at all times, our algorithm uses the outputs of six leg-configuration sensor models together with a priori knowledge of the ground and robot kinematics to compute instantaneous estimates of the 6-degrees-of-freedom (6-DOF) body pose. We implement this estimation procedure on the robot RHex by means of a novel sensory system incorporating a model relating compliant leg member strain to leg configuration delivered to the onboard CPU over a customized cheap high-performance local wireless network. We evaluate the performance of this algorithm at widely varying body speeds and over dramatically different ground conditions by means of a 6-DOF vision-based ground-truth measurement system (GTMS). We also compare the odometry performance to that of sensorless schemes—both legged as well as on a wheeled version of the robot—using GTMS measurements of elapsed distance.

Document Type

Journal Article

Subject Area

GRASP, Kodlab

Date of this Version

June 2005


Copyright 2005 IEEE. Reprinted from IEEE Transactions on Robotics, Volume 21, Issue 3, June 2005, pages 411-422.

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body pose estimation, hexapod robot, leg configuration, legged locomotion sensing, legged odometry, robot proprioception, strain-based sensor



Date Posted: 25 February 2008

This document has been peer reviewed.