Autonomous Motion Article 2011

Bayesian robot system identification with input and output noise

For complex robots such as humanoids, model-based control is highly beneficial for accurate tracking while keeping negative feedback gains low for compliance. However, in such multi degree-of-freedom lightweight systems, conventional identification of rigid body dynamics models using CAD data and actuator models is inaccurate due to unknown nonlinear robot dynamic effects. An alternative method is data-driven parameter estimation, but significant noise in measured and inferred variables affects it adversely. Moreover, standard estimation procedures may give physically inconsistent results due to unmodeled nonlinearities or insufficiently rich data. This paper addresses these problems, proposing a Bayesian system identification technique for linear or piecewise linear systems. Inspired by Factor Analysis regression, we develop a computationally efficient variational Bayesian regression algorithm that is robust to ill-conditioned data, automatically detects relevant features, and identifies input and output noise. We evaluate our approach on rigid body parameter estimation for various robotic systems, achieving an error of up to three times lower than other state-of-the-art machine learning methods

Author(s): Ting, J. and D’Souza, A. and Schaal, S.
Journal: Neural Networks
Volume: 24
Number (issue): 1
Pages: 99-108
Year: 2011
Bibtex Type: Article (article)
URL: http://www-clmc.usc.edu/publications/T/ting-NN2011.pdf
Cross Ref: p10405
Electronic Archiving: grant_archive
Note: clmc

BibTex

@article{Ting_NN_2011,
  title = {Bayesian robot system identification with input and output noise},
  journal = {Neural Networks},
  abstract = {For complex robots such as humanoids, model-based control is highly beneficial for accurate tracking while keeping negative feedback gains low for compliance. However, in such multi degree-of-freedom lightweight systems, conventional identification of rigid body dynamics models using CAD data and actuator models is inaccurate due to unknown nonlinear robot dynamic effects. An alternative method is data-driven parameter estimation, but significant noise in measured and inferred variables affects it adversely. Moreover, standard estimation procedures may give physically inconsistent results due to unmodeled nonlinearities or insufficiently rich data. This paper addresses these problems, proposing a Bayesian system identification technique for linear or piecewise linear systems. Inspired by Factor Analysis regression, we develop a computationally efficient variational Bayesian regression algorithm that is robust to ill-conditioned data, automatically detects relevant features, and identifies input and output noise. We evaluate our approach on rigid body parameter estimation for various robotic systems, achieving an error of up to three times lower than other state-of-the-art machine learning methods},
  volume = {24},
  number = {1},
  pages = {99-108},
  year = {2011},
  note = {clmc},
  slug = {ting_nn_2011},
  author = {Ting, J. and D'Souza, A. and Schaal, S.},
  crossref = {p10405},
  url = {http://www-clmc.usc.edu/publications/T/ting-NN2011.pdf}
}