Robust tracking control system for longitudinal manoeuvre of large aircraft
A near-stall condition refers to a critical flight situation in which an aircraft is operating at or near its stall velocity or the minimum speed required to maintain lift. During this condition, the aircraft’s aerodynamic performance is severely compromised, making precise control essential for...
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
2023
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/118263/ http://psasir.upm.edu.my/id/eprint/118263/1/118263.pdf |
| Summary: | A near-stall condition refers to a critical flight situation in which an aircraft is operating
at or near its stall velocity or the minimum speed required to maintain lift. During
this condition, the aircraft’s aerodynamic performance is severely compromised,
making precise control essential for the safe and reliable execution of manoeuvres,
including terrain avoidance, evasive manoeuvres, and safe landings or climbing. In
such a situation, maintaining stability and control becomes paramount to ensure the
safety of the aircraft and its occupants. As flight control systems continue to incorporate
the latest automation technology, it is essential to assess the effectiveness of
these systems in such conditions. However, aircraft models inherit nonlinearity due
to near-stall conditions. In addition to addressing the lack of effective control solutions
in existing systems, this thesis explores the application of sliding mode control
(SMC) to maintaining satisfactory flight performance during manoeuvres that
require rapid changes in attitude, altitude, and velocity in the tracking process. A
nonlinear aircraft model was developed for this purpose, and the model was transformed
into a nonlinear state space to provide an accurate representation of the aircraft
dynamics. To verify the model, open-loop analysis was employed based on the
trimming and linearisation of the model. Additionally, variants of SMC, including
integral SMC (ISMC) and non-singular terminal SMC (NTSMC), were integrated
into the aircraft model to evaluate their potential for enhancing flight stability and
performance. The model underwent various flight phase scenarios to demonstrate
the effectiveness of these control methods in challenging situations. The results were
compared with PID and SMC controllers as baselines. The study revealed that the
sliding surface variable is critical for determining the stability performance of the
aircraft, with the tested controllers outperforming the baselines. Notably, NTSMC
exhibited nearly a 60% improvement in response compared to PID. However, achieving
simultaneous control for attitudes and velocity has posed challenges, emphasizi-ing the necessity of a hierarchical control structure. |
|---|