Insperger, Tamás Antal and Milton, John (2014) Sensory uncertainty and stick balancing at the fingertip. BIOLOGICAL CYBERNETICS, 108 (1). pp. 85-101. ISSN 0340-1200
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Abstract
The effects of sensory input uncertainty, ε , on the stability of time-delayed human motor control are investigated by calculating the minimum stick length, ℓcrit , that can be stabilized in the inverted position for a given time delay, τ . Five control strategies often discussed in the context of human motor control are examined: three time-invariant controllers [proportional–derivative, proportional–derivative–acceleration (PDA), model predictive (MP) controllers] and two time-varying controllers [act-and-wait (AAW) and intermittent predictive controllers]. The uncertainties of the sensory input are modeled as a multiplicative term in the system output. Estimates based on the variability of neural spike trains and neural population responses suggest that ε≈7 –13 %. It is found that for this range of uncertainty, a tapped delay-line type of MP controller is the most robust controller. In particular, this controller can stabilize inverted sticks of the length balanced by expert stick balancers (0.25–0.5 m when τ≈0.08 s). However, a PDA controller becomes more effective when ε>15% . A comparison between ℓcrit for human stick balancing at the fingertip and balancing on the rubberized surface of a table tennis racket suggest that friction likely plays a role in balance control. Measurements of ℓcrit,τ , and a variability of the fluctuations in the vertical displacement angle, an estimate of ε , may make it possible to study the changes in control strategy as motor skill develops.
Item Type: | Article |
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Uncontrolled Keywords: | NOISE; MODEL; TIME-DELAY; delay systems; SMITH PREDICTOR; motor control; FEEDBACK-CONTROL; Inverted pendulum; INTERMITTENT CONTROL; ACT-AND-WAIT; control; Sensory uncertainties; feedback delay; Stick balancing |
Subjects: | Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia > QH3020 Biophysics / biofizika T Technology / alkalmazott, műszaki tudományok > T2 Technology (General) / műszaki tudományok általában |
SWORD Depositor: | MTMT SWORD |
Depositing User: | MTMT SWORD |
Date Deposited: | 03 Apr 2014 06:47 |
Last Modified: | 03 Apr 2014 07:18 |
URI: | http://real.mtak.hu/id/eprint/11262 |
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