Controls

Aircraft, launch vehicles and satellites represent complicated aerospace systems comprising of many subsystems that exhibit a wide variety of complex nonlinear dynamical behavior. Examples of such complex behavior include the phenomena of surge and stall of compressors used in jet engines, wing rock oscillations and jump phenomena in combat aircraft, and structural vibrations in flexible space structures. These complex phenomena require equally complex control strategies to meet the stringent performance requirements on aerospace systems. The dynamical behavior of aerospace systems as well as the control strategies that it warrants present a challenge to the analysis and design of aerospace control systems.

Techniques based on bifurcation theory, nonlinear dynamical systems theory, linear and nonlinear control theory, stability theory, and neural and fuzzy control are being developed and applied to problems in aircraft flight dynamics and control, combustion acoustics, spacecraft attitude dynamics and control, and control of structural vibrations. The following links provide glimpses of recent and ongoing work at the Department in the area of Dynamics and Control.

Literal Approximations to Aircraft Dynamic Modes

The derivation of literal approximations to aircraft dynamic modes has engaged the attention of flight dynamicists for nearly a century since the work of Lanchester in the 1900"s. The topic is widely covered in all textbooks, yet it is universally accepted that the present approximations are often unsatisfactory. Attempts by several researchers to address this problem over the years have been largely unsuccessful. The problem has finally been resolved in recent work at IITB which shows that the existing approximations are faulty due to a crucial error in the derivations. A new formulation of the equations for flight stability has been derived and correct literal approximations obtained which are expected to replace the existing presentation in textbooks.