(Georgia Institute of Technology, 2005-06)
Calise, Anthony J.; Johnson, Eric N.; Sattigeri, Ramachandra J.; Watanabe, Yoko; Madyastha, Venkatesh
This paper discusses estimation and guidance
strategies for vision-based target tracking. Specific
applications include formation control of multiple unmanned
aerial vehicles (UAVs) and air-to-air refueling. We assume
that no information is communicated between the aircraft,
and only passive 2-D vision information is available to
maintain formation. To improve the robustness of the
estimation process with respect to unknown target aircraft
acceleration, the nonlinear estimator (EKF) is augmented with
an adaptive neural network (NN). The guidance strategy
involves augmenting the inverting solution of nonlinear line-of-sight (LOS) range kinematics with the output of an
adaptive NN to compensate for target aircraft LOS velocity.
Simulation results are presented that illustrate the various
approaches.
(Georgia Institute of Technology, 2004-12)
Johnson, Eric N.; Calise, Anthony J.; Sattigeri, Ramachandra J.; Watanabe, Yoko; Madyastha, Venkatesh
This paper implements several methods for
performing vision-based formation flight control of multiple
aircraft in the presence of obstacles. No information is
communicated between aircraft, and only passive 2-D vision
information is available to maintain formation. The methods
for formation control rely either on estimating the range from
2-D vision information by using Extended Kalman Filters or
directly regulating the size of the image subtended by a leader
aircraft on the image plane. When the image size is not a
reliable measurement, especially at large ranges, we consider
the use of bearing-only information. In this case, observability
with respect to the relative distance between vehicles is
accomplished by the design of a time-dependent formation
geometry. To improve the robustness of the estimation process
with respect to unknown leader aircraft acceleration, we
augment the EKF with an adaptive neural network. 2-D and
3-D simulation results are presented that illustrate the various
approaches.