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.