A framework for constrained control allocation using CFD-based tabular data

• 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.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Rymd- och flygteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Aerospace Engineering (hsv//eng)

Nyckelord

Aerodynamic forces

Automated generation

CFD codes

Constrained control allocation

Control allocation problem

Data tables

Deflection angles

Efficient sampling

Fighter trainers

Flow solver

Large data

Look up table

Lower limits

Mode shapes

Multidimensional arrays

Multiple control surfaces

Reduced geometry

State vector

Surface deflection

Tabular data

Test case

Trailing edges

University of Liverpool

Vortex lattice method

Aerodynamics

Aerospace engineering

Boundary conditions

Control surfaces

Data fusion

Deflection (structures)

Surface treatment

Table lookup

Tornadoes

Vortex flow

Computational fluid dynamics

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