Cancellation of Biodynamic Feedthrough in Vehicle Control Tasks
Szabolcs Sövényi and R. Brent Gillespie
Submitted July 2005, IEEE Transactions on Control Systems Technology
Abstract—Biodynamic feedthrough refers to the transmission
of vehicle motion from the seat through the driver’s body to the
steering or speed control interface where it produces unintended
vehicle control commands. This pathway through the body closes
a feedback loop that degrades driving performance and can even
produce sustained oscillations in the human-vehicle system. In
certain instances these oscillations can jeopardize vehicle safety.
In this paper we propose and test a model-based cancellation
controller to mitigate the effects of biodynamic feedthrough.
The biodynamic model is constructed in a preliminary system
identification experiment in which vehicle acceleration and
control interface interaction force are measured. The system
identification experiment is carefully designed to capture the biodynamic
transmittance rather than the driving point impedance
at the control interface. In operation, the controller processes
vehicle acceleration measurements through a transfer function
model of the human biodynamics and a motor imposes the
result as a torque that acts directly on the manual control
interface.We investigated the efficacy of model-based cancellation
by quantifying the manual performance of 12 human subjects
using a joystick to control displacements of a single-axis motion
platform upon which they were seated. Biodynamic models were
individually fit and tested as cancellation controllers for each
subject. Comparing performance with and without cancellation
in place, the cancellation controller reduced oscillation spectral
energy in the 1-7Hz band by 75 % and reduced the root mean
square tracking error by 44 %. The cancellation controller also
had a positive effect on the disturbance response of the drivervehicle
system.