Model-Based Cancellation of Biodynamic Feedthrough
Using a Force-Reflecting Joystick
R. Brent Gillespie and Szabolcs Sovenyi
Submitted April 2005, ASME Journal of Dynamic Systems, Measurement, and Control
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 verify the use of a motorized control
interface to cancel the effects of biodynamic feedthrough. The cancellation
controller is based on a parametric model fit to experimental data collected
using an accelerometer on the vehicle and a force sensor on a temporarily
immobilized manual control interface. The biodynamic model and system
identification experiment are in turn based on a carefully constructed model of
the coupled vehicle-operator system. The impact of biodynamic feedthrough and
the efficacy of the cancellation controller are estimated by comparing the
performance of 12 human subjects using a joystick to carry out a pursuit
tracking task on-board a single-axis motion platform. The crossover model is
used as a basis for developing three performance metrics. After first confirming
the deleterious effects of platform motion, cancellation controllers derived
from individually fit biodynamic feedthrough models were shown to significantly
improve performance. With the cancellation controller active on-board the moving
platform, performance levels were almost half-way restored to the levels
demonstrated on the stationary platform.