  This study presents a technique to safely control the Sit-to-Stand movement
of powered lower limb orthoses in the presence of parameter uncertainty. The
weight matrices used to calculate the finite time horizon linear-quadratic
regulator (LQR) gain in the feedback loop are chosen from a pool of candidates
as to minimize a robust performance metric involving induced gains that measure
the deviation of variables of interest in a linear time-varying (LTV) system,
at specific times within a finite horizon, caused by a perturbation signal
modeling the variation of the parameters. Two relevant Sit-to-Stand movements
are simulated for drawing comparisons with the results documented in a previous
work.
