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On-line learning for humanoid robot systems


Conference Paper


Humanoid robots are high-dimensional movement systems for which analytical system identification and control methods are insufficient due to unknown nonlinearities in the system structure. As a way out, supervised learning methods can be employed to create model-based nonlinear controllers which use functions in the control loop that are estimated by learning algorithms. However, internal models for humanoid systems are rather high-dimensional such that conventional learning algorithms would suffer from slow learning speed, catastrophic interference, and the curse of dimensionality. In this paper we explore a new statistical learning algorithm, locally weighted projection regression (LWPR), for learning internal models in real-time. LWPR is a nonparametric spatially localized learning system that employs the less familiar technique of partial least squares regression to represent functional relationships in a piecewise linear fashion. The algorithm can work successfully in very high dimensional spaces and detect irrelevant and redundant inputs while only requiring a computational complexity that is linear in the number of input dimensions. We demonstrate the application of the algorithm in learning two classical internal models of robot control, the inverse kinematics and the inverse dynamics of an actual seven degree-of-freedom anthropomorphic robot arm. For both examples, LWPR can achieve excellent real-time learning results from less than one hour of actual training data.

Author(s): Conradt, J. and Tevatia, G. and Vijayakumar, S. and Schaal, S.
Book Title: Proceedings of the Seventeenth International Conference on Machine Learning (ICML 2000)
Volume: 1
Pages: 191-198
Year: 2000

Department(s): Autonomous Motion
Bibtex Type: Conference Paper (inproceedings)

Address: Stanford, CA
Cross Ref: p1423
Note: clmc
URL: http://www-clmc.usc.edu/publications/C/conradt-ICML2000.pdf


  title = {On-line learning for humanoid robot systems},
  author = {Conradt, J. and Tevatia, G. and Vijayakumar, S. and Schaal, S.},
  booktitle = {Proceedings of the Seventeenth International Conference on Machine Learning (ICML 2000)},
  volume = {1},
  pages = {191-198},
  address = {Stanford, CA},
  year = {2000},
  note = {clmc},
  crossref = {p1423},
  url = {http://www-clmc.usc.edu/publications/C/conradt-ICML2000.pdf}