Alternative Trim Analysis Formulations for Vehicles with Redundant Multi-Axis Control Surfaces

Garmendia, Daniel C.; Mavris, Dimitri N.

doi:10.2514/1.c033184

Cited by 8 publications

(12 citation statements)

References 22 publications

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“…Equilibria for this study were performed using all elevons with equal deflection. Other studies showed the benefits of segregating trim and maneuver control surfaces [6], but this trade is out of the scope of our work. However, for maneuvers, each of the 10 elevons is actuated independently, through a control allocation strategy presented in Sec.…”

Section: A Linearized State-space Representation Of Flight Dynamics mentioning

confidence: 99%

“…Major challenges are yet to be solved before a potential entry into service, including control-related issues [5]. These issues first originate from the nature of the control devices used for this configuration: the BWB (also known in the literature as hybrid wingbody [6]) is controlled with multicontrol surfaces (also named elevons), usually spanning the whole trailing edge and acting as pitch and roll devices. Among the challenges associated with this technology, new handling quality criteria are required in order to take into account the combined authority of control surfaces on longitudinal and lateral axes.…”

Section: Introductionmentioning

confidence: 99%

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Multicontrol Surface Optimization for Blended Wing–Body Under Handling Quality Constraints

Denieul

Bordeneuve-Guibé

Alazard

et al. 2018

Journal of Aircraft

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Section: A Linearized State-space Representation Of Flight Dynamics mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multicontrol Surface Optimization for Blended Wing–Body Under Handling Quality Constraints

Denieul

Bordeneuve-Guibé

Alazard

et al. 2018

Journal of Aircraft

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“…As the scaled model will feature three independent elevons, the vehicle can be considered as a multi-redundant control-surfaces vehicle [13]. Trimming can therefore be performed in various ways.…”

Section: Trim Analysismentioning

confidence: 99%

Experimental Aerodynamic Analysis of a 4.6%-Scale Flying-V Subsonic Transport

Palermo

Vos

2020

AIAA Scitech 2020 Forum

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The experimental investigation into the aerodynamic characteristics of a 4.6%-scale half-model of a flying-wing transport aircraft is detailed. The study is performed in an open-jet wind tunnel where forces and moments are recorded using a 6-axis balance. Two control surfaces in the outboard wing are deflected to measure their effect in terms of lift, drag, and pitching moment up to a Reynolds number of 1 million. The results are subsequently combined with the estimated thrust force using a flight mechanics model of the aircraft in order to predict the most forward and most aft center-of-gravity locations for which the aircraft can be balanced with the control surfaces, while still being statically stable. The results show that the aircraft can attain an untrimmed maximum lift coefficient of 1.02 at an angle of attack of 35 degrees. Furthermore, the pitching moment around the leading-edge of the mean geometric chord is negatively correlated to the angle of attack up to 19 degrees, after which a strong pitch-break is observed, making the aircraft statically unstable. This is associated with a forward shift of the aerodynamic center to a longitudinal position 35%c ahead of the moment reference point which is caused by the formation of strong vortices over the wing surface. The effectiveness of the control surfaces hardly deteriorates with angle of attack and all three control surfaces are shown to be effective up to the maximum lift coefficient. Analysis shows that the center-ofgravity location should reside between [-7.5; 0.5] %c, in power-off conditions, and between [-6; 1] %c, in power-on conditions, from the leading edge of the mean geometric chord to ensure an ultimate static stability margin of 4.4% as well and a minimum landing speed of 20 m/s. Within these ranges, trimmed maximum lift coefficient values of 0.68 and 0.66 can be achieved respectively in power-off and power-on conditions.

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“…The case of under-determined trim problems due to control effectors redundancy has been analyzed in [5], with application to the Blended Wing Body (BWB) aircraft configuration. Two approaches to the trim problem are proposed: 1) A Minimum Drag Trim Optimization (MDTO) formulation applied to 6-DoF dynamics.…”

Section: Introductionmentioning

confidence: 99%

“…Comparing the two approaches presented in [5] would be overall unfair. The MDTO is an optimization-based approach that exploits controls redundancy to minimize drag at trim conditions.…”

Section: Introductionmentioning

confidence: 99%

Trim for Maximum Control Authority using the Attainable Moment Set

Varriale

Veldhuis

Voskuijl

2020

AIAA Scitech 2020 Forum

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This paper presents a method to find trimmed flight conditions while maximizing the available control authority about one or more motion axes. Maximum pitch-up, or lift-up, control authority could find interesting application in aborted landing situations, while maximum balanced control authority about all motion axes is a reformulation of the classic concept of minimum control effort. The trim problem is formulated in the form of a constrained optimization problem. The constraints and the objective function are obtained by exploiting the geometric properties of the Attainable Moment Set, a convex polytope containing the forces and moments attainable by the aircraft control effectors. The method is applied to an innovative box-wing aircraft configuration called PrandtlPlane, whose double wing system can accommodate a large number of control surfaces, and hence allow Pure Torque and Direct Lift Control possibilities. Control surface deflections are compared for trim conditions with maximum control authority in the pitch axis, in the lift axis, and maximum balanced control authority, for symmetric and asymmetric flight. Results show that the method is able to capitalize on the angle of attack or the throttle setting to obtain the control surfaces deflections which maximize control authority in the assigned direction.

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Alternative Trim Analysis Formulations for Vehicles with Redundant Multi-Axis Control Surfaces

Cited by 8 publications

References 22 publications

Multicontrol Surface Optimization for Blended Wing–Body Under Handling Quality Constraints

Multicontrol Surface Optimization for Blended Wing–Body Under Handling Quality Constraints

Experimental Aerodynamic Analysis of a 4.6%-Scale Flying-V Subsonic Transport

Trim for Maximum Control Authority using the Attainable Moment Set

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