Abstract:
This paper aims to establish block-structured
nonlinear model (Hammerstein model) to predict oxygen uptake
during moderate treadmill exercises. In order to model the
steady state relationship between oxygen uptake (oxygen consumption)
and walking speed, six healthy male subjects walked
on a motor driven treadmill at six different speed (2,3,4,5,6,
and 7 km/h). The averaged oxygen uptake of exercisers at
steady state was measured by a mixing chamber based gas
analyzer(AEI Moxus Metabolic Cart). Based on these reliable
experiment data, a nonlinear static function was obtained by
using Support Vector Regression. In order to capture the
dynamics of oxygen uptake, a suitable Pseudo Random Binary
Signal (PRBS) input was designed and implemented on a
computer controlled treadmill. Breath by breath analysis of all
exercisers’ dynamic responses (PRBS responses) to treadmill
walking was performed. A useful ARX model is identified to
justify the measured oxygen uptake dynamics within the aerobic
range. Finally, a Hammerstein is achieved, which is useful for
the control system design of oxygen uptake regulation during
treadmill exercises.
