| dc.creator |
Carnduff, S. D. |
|
| dc.creator |
Cooke, A. K. |
|
| dc.date |
2008-04-24T10:23:20Z |
|
| dc.date |
2008-04-24T10:23:20Z |
|
| dc.date |
2008-03 |
|
| dc.date.accessioned |
2022-05-09T10:17:13Z |
|
| dc.date.available |
2022-05-09T10:17:13Z |
|
| dc.identifier |
S. D. Carnduff and A. K. Cooke, Formulation and System Identification of the Equations of Motion for a Dynamic Wind Tunnel Facility. College of Aeronautics Report No. 0801, March 2008 |
|
| dc.identifier |
http://hdl.handle.net/1826/2516 |
|
| dc.identifier.uri |
https://reports.aerade.cranfield.ac.uk/handle/1826/2516 |
|
| dc.description |
This document describes the equations of motion of an aircraft model tested in Cranfield’s 4 degreeof-
freedom (DoF) wind tunnel facility. In previous research, the equations have been derived assuming
that the model’s centre of gravity (cg) is coincident with the gimbal mechanism about which the model
rotates on the rig. However, in this report a general approach is taken with the cg assumed to be located
away from the gimbal. The equations are developed from first principles and reduced to a linearised
form where motion can be represented as small perturbations about trim. The equations are also decoupled
into longitudinal and lateral/direction expressions and converted into state space form. It had
been found in practice that models tested in the facility are very responsive in heave and can only be
operated open-loop if movement is restricted to purely rotational motion. Therefore, the equations for
this 3DoF case are also developed. Having obtained theoretical expressions, a series of wind tunnel
tests were conducted on a 1/12 scale BAe Hawk model in order to establish if the theoretical relations
were valid in practice. The particular technique used in testing the model was dynamic simulation and
the analysis of the experimental data was performed using system identification. An established model
structure determination procedure is used to determine which stability and control derivatives should be
included in the equations of motion. Frequency domain, equation error parameter estimation is then
employed to obtain numerical values for the stability and control derivatives. For both the longitudinal
and lateral/directional examples described, the final model structure obtained from experiment matches
that derived from theory. Derivatives values obtained from parameter estimation and empirical analysis
are also in good agreement. |
|
| dc.language |
en |
|
| dc.publisher |
Cranfield University |
|
| dc.relation |
College of Aeronautics Report;0801 |
|
| dc.relation |
COA;0801 |
|
| dc.title |
Formulation and System Identification of the Equations of Motion for a Dynamic Wind Tunnel Facility. |
|
| dc.type |
Technical Report |
|