Title
Preintegrated Velocity Bias Estimation to Overcome Contact Nonlinearities in Legged Robot Odometry
Abstract
In this paper, we present a novel factor graph formulation to estimate the pose and velocity of a quadruped robot on slippery and deformable terrain. The factor graph introduces a preintegrated velocity factor that incorporates velocity inputs from leg odometry and also estimates related biases. From our experimentation we have seen that it is difficult to model uncertainties at the contact point such as slip or deforming terrain, as well as leg flexibility. To accommodate for these effects and to minimize leg odometry drift, we extend the robot's state vector with a bias term for this preintegrated velocity factor. The bias term can be accurately estimated thanks to the tight fusion of the preintegrated velocity factor with stereo vision and IMU factors, without which it would be unobservable. The system has been validated on several scenarios that involve dynamic motions of the ANYmal robot on loose rocks, slopes and muddy ground. We demonstrate a 26% improvement of relative pose error compared to our previous work and 52% compared to a state-of-the-art proprioceptive state estimator.
Year
DOI
Venue
2020
10.1109/ICRA40945.2020.9197214
2020 IEEE International Conference on Robotics and Automation (ICRA)
Keywords
DocType
Volume
preintegrated velocity bias estimation,contact nonlinearities,legged robot odometry,factor graph formulation,quadruped robot,slippery terrain,deformable terrain,preintegrated velocity factor,leg flexibility,leg odometry drift,IMU factors,ANYmal robot,proprioceptive state estimator
Conference
2020
Issue
ISSN
ISBN
1
1050-4729
978-1-7281-7396-2
Citations 
PageRank 
References 
0
0.34
9
Authors
3
Name
Order
Citations
PageRank
David Wisth182.33
Marco Camurri2382.72
Maurice F. Fallon358837.73