Application of Robust Control Design Techniques to the Aeroservoelastic Design Optimization of a Very Flexible UAV Wing

Abstract

A multidisciplinary design optimization framework is developed to integrate control system design and aerostructural design of an aircraft in the conceptual design phase. The aircraft's wings are very flexible and the aircraft's aeroservoelastic equations of motion are derived and integrated with the aerostructural analysis and control system design. A two degree of freedom multi-objective control architecture capable of structural load alleviation is proposed. The linear matrix inequalities technique is used to express the control design process as a convex optimization problem. Time-domain analysis of the aircraft encountering an atmospheric gust is included in the design process. The optimal trade-off between aerodynamics, structures and control systems is found by maximizing the endurance subjected to stress constraints.

Mixed-Norm Multi-Objective Robust Controller Applied to a Very Flexible Aircraft

“…The kinetic and potential energies can be expressed in terms of translational and rotational velocities and structural deformations (more detailed derivation of kinetic and potential energy terms can be found in authors' previous work 24 ). Substituting those terms into Equations (1, 2 and 6) and rearranging them, the equations of motion of a deformable aircraft become   …”

Attenuation of Aircraft Flexible Modes during Maneuvering Flight

“…Wildschek et al 17,18 introduces an adaptive feedforward controller to provide wing load alleviation, identifying on-line the frequency content of important flexible modes based on accelerometers placed along the fuselage and wing. Recently, Haghighat, Liu and Martins applied nonlinear control techniques such as Model Predictive Control, 19 Robust Linear Matrix Inequality 20 and Robust Mixed-Norm Multi-Objective, 21 considering an aeroservoelastic model with integrated rigid-body dynamics and flexible dynamics.…”

Applications of the unsteady vortex-lattice method in aircraft aeroelasticity and flight dynamics

“…The steady VLM has since been employed in a number of applications, such as modelling yacht sails [48], in the computation of stability derivatives and flight dynamics analysis [49][50][51], in aerodynamic interference of aircraft [52][53][54], or in multidisciplinary optimisation [55], among many others.…”