Aeroservoelastic modeling and analysis of a missile control surface with a nonlinear electromechanical actuator

Nalci M. O., KAYRAN A.

AIAA AVIATION 2014 -AIAA Atmospheric Flight Mechanics Conference 2014, Atlanta, GA, United States Of America, 16 - 20 June 2014 identifier

  • Publication Type: Conference Paper / Full Text
  • City: Atlanta, GA
  • Country: United States Of America
  • Middle East Technical University Affiliated: Yes


In this study, aeroservoelastic modeling and analysis of a missile control surface which is operated and controlled by a power limited, nonlinear electromechanical actuator is performed. Linear models of the control fin structure and aerodynamics together with the nonlinear servo-actuation system are built and integrated. The resulting aeroservoelastic system is analyzed both in time and frequency domain. Structural model of the control fin is based on the finite element model of the fin. Aerodynamic model of the control fin is based on the Generalized Aerodynamic Force (GAF) Matrix model which is generated in accordance with the finite element model of the fin. In order to be able to represent the aerodynamic forces in the continuous frequency domain, and the time domain, a rational function approximation formulation of the GAF matrices is utilized. Both the elastic and the rigid body motion of the missile control fin are modeled through modal discretization, so that the interaction between the aeroelastic system and the control system dynamics can be treated appropriately. A PD controller synthesis is carried out using the Root Locus Method, by neglecting the flexibility of the fin and unsteady aerodynamic effects on the fin, as if the fin is rigid and the aerodynamics is steady. The shortcomings of these assumptions are discussed under the effect of aeroelastic loading. A third order servoactuation system together with the PD controller is integrated to the aeroelastic system, so that the limit cycle oscillations of the aeroservoelastic system due to power limit saturation could be studied. Two alternative, common position feedback paths for the PD controller are used and the resulting aeroservoelastic systems are simulated in response to various control commands. It is shown that the stability and dynamic performance of the aeroservoelastic system also depends on the selection of the feedback path, when aeroelastic dynamics is present.