Title: Nataraj R, Audu ML, Kirsch RF, Triolo RJ. Center of mass acceleration feedback control for standing by functional neuromuscular stimulation: A simulation study. J
1Figure 1. Overall model system. Two parallel
controllers act to maintain three-dimensional
(3-D) model of bipedal spinal cord injury stance
at set point position against postural
perturbations. (1) Functional neuromuscular
stimulation (FNS) controller modulates trunk and
lower-limb muscle excitations according to center
of mass (COM) acceleration feedback in
anterior-posterior (AP) and medial-lateral (ML)
directions driving artificial neural network
(ANN). ANN is trained to output muscle excitation
changes that counter measured effects induced by
disturbances and net recovery responses upon COM.
(2) Upper-limb (UL) controller, representing user
volitional loading, produces 3-D point forces at
shoulders according to position errors relative
to shoulder set point posture. COM acceleration
and shoulder positional errors are expressed in
globally fixed 3-D Cartesian coordinates. Gains
for UL control are determined according to
Ziegler-Nichols tuning rules. FNS controller
gains are optimized using global-search algorithm
to minimize UL controller output ("loading")
against perturbations. ME muscle excitations, P
proportional gain, PID proportional-integral-d
erivative, SCI spinal cord injury, SE
shoulder errors, SF shoulder forces.
Nataraj R, Audu ML, Kirsch RF, Triolo RJ. Center
of mass acceleration feedback control for
standing by functional neuromuscular stimulation
A simulation study. J Rehabil Res Dev.
201249(2)27996.http//dx.doi.org/10.1682/JRRD.
2010.12.0235