Spelling suggestions: "subject:"airplanes -- andhandling characteristics"" "subject:"airplanes -- tandbehandling characteristics""
1 |
An analytical investigation of aircraft handling qualitiesGiles, Richard F. January 1968 (has links)
During the design of an aircraft it becomes necessary to predict the aircraft handling qualities. Previously, this has been done through the use of pilot opinion ratings of similar vehicles. However, it is desirable to develop more objective means of predicting handling qualities which also do not require the expensive flight testing or simulation necessary to obtain pilot ratings directly.
An analysis of the closed-loop pilot-airframe system is performed, utilizing the linear human-pilot transfer function in conjunction with conventional servoanalysis techniques. Boundaries are developed on aircraft frequency and damping ratio for "good" longitudinal short-period control. The lateral phugoid mode is also investigated and the conclusion reached is that this mode cannot be controlled in a manner resulting in "good" pilot ratings.
Comparison of the results obtained for the longitudinal short-period mode with experimental data indicates that the analysis is valid. Experimental data is lacking for comparison in the case of the lateral phugoid mode. / M.S.
|
2 |
Sliding-mode control of the super maneuverable aircraftKoo, Chang Sul 13 July 1993 (has links)
In this thesis, A nonlinear methodology for the control of the highly
maneuverable, high performance aircraft HARV (F-18) is studied by using sliding-mode
control (SMC). This control law, which takes a continuous function when the
input constraints are not considered, satisfies the reachability condition by which
concerned states are driven to their sliding surfaces. Especially, this SMC is
generalized for the so-called (square) uncoupled multi-input multi-output (MIMO)
system by the use of error dynamics and applied directly to the nonlinear aircraft
system without linearizing the system.
For the practical application of the SMC to aircraft with input constraints, two
control schemes are used, considering that variations of pitch rate q directly affect
variations of the angle of attack. The first scheme consists of an ��-q control for the
fast response. The second scheme consists an a-control for making the output
approach its sliding surface slowly by setting boundary layers and adjusting reachable
speeds to the sliding surface.
Robustness to parameter uncertainties and disturbances is also studied for the
SMC. Especially, when the effect of parameter uncertainties is severe, then multiple
boundary layers are set in the neighborhood of sliding surface, in which different
reachable speeds to the sliding surface are used to sustain the concerned state within
the boundary layer and to reduce the effect of chattering. / Graduation date: 1994
|
Page generated in 0.0993 seconds