A framework for constrained control allocation using CFD based tabular data

Abstract

This paper describes a framework for control allocation problem using Computational Fluid Dynamics (CFD) aerodata, which is represented by a multidimensional array of dimensionless coefficients of aerodynamic forces and moments, stored as a function of the state vector and control-surface deflections. The challenges addressed are, first, the control surface treatment for the automated generation of aerodata using CFD and, second, sampling and data fusion to allow the timely calculation of large data tables. In this framework, the generation of aerodynamic tables is described based on an efficient sampling/data fusion approach. Also, the treatment of aerodynamics of control surfaces is being addressed for three flow solvers: TORNADO, a vortex-lattice method, and two CFD codes, EDGE from the Swedis Defence Agency and PMB from the University of Liverpool. In TORNADO, the vortex points located at the trailing edge of the flaps are rotated around the hinge line to simulate the deflected surfaces. The transpiration boundary conditions approach is used for modeling moving flaps in EDGE, whereas, the surface deflection is achieved using mode shapes in PMB. The test cases used to illustrate the approaches is the Ranger 2000 fighter trainer and a reduced geometry description of Boeing 747-100. Data tables are then generated for the state vector and multiple control surface deflections. The look-up table aerodata are then used to resolve the control allocation problem under the constraint that each surface has an upper and lower limit of deflection angle.

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Identifiers

ORCID for A. Da Ronch: orcid.org/0000-0001-7428-6935

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