Model-Based Cancellation of Biodynamic Feedthrough
Using a Force-Reflecting Joystick
R. Brent Gillespie and Szabolcs Sövényi
ASME Journal of Dynamic Systems, Measurement, and Control, to appear.
Abstract�Manual control performance on-board a moving
vehicle is often impeded by biodynamic feedthrough�the effects
of vehicle motion feeding through the operator's body to produce
unintended forces on the control interface. In this paper, we
propose and experimentally test a model-based controller that
acts through a motorized manual interface to cancel the effects
of biodynamic feedthrough. The cancellation controller is based
on characterization data collected using an accelerometer on the
vehicle and a force sensor embedded in the manual interface
and a protocol under which the manual interface is temporarily
immobilized while in the grip of the operator. The biodynamic
model fit to the data is based in turn on a carefully constructed
model of the coupled vehicle-operator system. The impact of
biodynamic feedthrough and the ability of the model-based controller
to cancel its effects were estimated through an experiment
in which 12 human subjects used a joystick to carry out a
pursuit tracking task on-board a single-axis motion platform.
Cancellation controllers derived from biodynamic models fit individually
to each subject significantly improved pursuit tracking
performance, as evidenced by a 27% reduction in root-mean-square
tracking error, a 35% improvement in time-on-target,
and an increase in crossover frequency from 0.1 to 0.14 Hz.