Abstract
The goal of this study is to create and examine machine learning algorithms that adapt in a controlled and cadenced way to foster a harmonious learning environment between the user and the controlled device. To evaluate these algorithms, we have developed a simple experimental framework. Subjects wear an instrumented data glove that records finger motions. The highdimensional glove signals remotely control the joint angles of a simulated planar two-link arm on a computer screen, which is used to acquire targets. A machine learning algorithm was applied to adaptively change the transformation between finger motion and the simulated robot arm. This algorithm was either LMS gradient descent or the Moore-Penrose (MP) pseudoinverse transformation. Both algorithms modified the glove-to-joint angle map so as to reduce the endpoint errors measured in past performance. The MP group performed worse than the control group (subjects not exposed to any machine learning), while the LMS group outperformed the control subjects. However, the LMS subjects failed to achieve better generalization than the control subjects, and after extensive training converged to the same level of performance as the control subjects. These results highlight the limitations of coadaptive learning using only endpoint error reduction.
Original language | English (US) |
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Article number | 4776455 |
Pages (from-to) | 1502-1511 |
Number of pages | 10 |
Journal | IEEE Transactions on Biomedical Engineering |
Volume | 56 |
Issue number | 5 |
DOIs | |
State | Published - May 2009 |
Funding
Manuscript received June 13, 2008; revised October 10, 2008. First published February 6, 2009; current version published May 22, 2009. This work was supported in part by the Craig H. Neilsen Foundation, in part by the National Institute of Neurological Disorders and Stroke (NINDS) under Grant NS35673, Grant NS 048845, and Grant 1R21HD053608, and in part by the Northwestern University’s Biomedical Engineering Department. Asterisk indicates corresponding author. *Z. Danziger is with Northwestern University, Evanston, IL 60208 USA, and also with the Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL 60611 USA (e-mail: zacharydanziger2011@ u.northwestern.edu).
Keywords
- Adaptive learning
- Hand posture
- Human- machine interface
- Machine learning
ASJC Scopus subject areas
- Biomedical Engineering