Simulation of the Dynamics of Helicopter Slung Load Systems

Cicolani, Luigi S.; Kanning, Gerd; Synnestvedt, Robert

doi:10.4050/jahs.40.44

Cited by 34 publications

(22 citation statements)

References 8 publications

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“…However, several studies have addressed the behavior of configurations with multiple attachment points. Reference will only be made here to an assessment of the state of the art for multi-point suspension configurations, presented by Sheldon [10], to an in-depth theoretical study of the dynamics of a 2-suspension point, 4-cable load configuration subsequently carried out by Prabhakar [11], and to a paper by Cicolani et al [12] which proposes a formulation valid for arbitrary numbers of aircraft, loads, and suspension points.…”

Section: More Recently Cicolani Et Al Have Reported the Results Of mentioning

confidence: 99%

Flight Dynamics of an Articulated Rotor Helicopter with an External Slung Load

Fusato¹,

Guglieri²,

Celi³

2001

j am helicopter soc

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The paper presents a study of the flight dynamics of an articulated rotor helicopter carrying a suspended load. The aircraft model includes rigid body dynamics, individual flap and lag blade dynamics, and inflow dynamics. The load is a point mass with a single suspension point. Results were obtained for load masses of up to 2000 kg, with load-tohelicopter mass ratios of up to 28%, cable lengths from 3 to 8 m, turn rates of up to 16 deg/sec, and advance ratios of up to 0.3. The load affects trim primarily through the overall increase in the weight of the aircraft; the influence of cable length is negligible. Substantial coupling can occur between the Dutch roll and the load modes. Because of this coupling, the Dutch roll damping can decrease with a deterioration of handling qualities. The effects on the phugoid are very small. A suspended load modifies the roll frequency response by adding a notch to the gain curves and a 180-degree jump in the phase curves at the pendulum frequencies of the load. The changes in bandwidth and phase delay are small. Notation a L Absolute acceleration of the suspended load, Eq. (4). D Aerodynamic force vector acting on the load, Eq. (6). F H Force applied by the load to the helicopter, Eq. (8). f L Vector of load equations of motion, Eq. (7). i B , j B , k B Unit vectors of the body axis coordinate system (Figure 1). i G , j G , k G Unit vectors of the gravity axis system; the k G vector is directed along the vertical. i H , j H , k H Unit vectors of hook coordinate system (Figure 1). l Cable length. m Mass of the suspended load. n T Load factor. p, q, r Roll, pitch, and yaw rate of the helicopter. R H Position vector of the suspension point with respect to the aircraft CG, Eq. (2). R L Position vector of the load with respect to the suspension point, Eq. (1). S L Equivalent flat plate area of the suspended load. x H , y H , z H Components of the position vector of the suspension point with respect to the aircraft center of mass (Figure 1). Greek Symbols and Subscripts θ L , φ L Coordinates of the suspended load (Figure 1). θ F , φ F Pitch and roll angle of the fuselage. µ Advance ratio.

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Section: More Recently Cicolani Et Al Have Reported the Results Of mentioning

confidence: 99%

Flight Dynamics of an Articulated Rotor Helicopter with an External Slung Load

Fusato¹,

Guglieri²,

Celi³

2001

j am helicopter soc

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“…Searching in the specialist literature for papers on this particular area of load failures revealed that the subject has not been well investigated. The publications found are somewhat sparse, many of them relating only to the subject of modelling of the dynamics of a helicopter with a slung load (1)(2)(3)(4)(5)(6)(7) , the dynamic instabilities of a slung load (8)(9)(10)(11)(12)(13)(14)(15)(16)(17) , handling qualities of helicopter/slung load system (18)(19)(20)(21) or modelling the control system of a helicopter with a slung load (22,23) . A few publications have been identified dealing with load problems; however, they address mainly a rather different problem from that considered in the present paper, i.e.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Chinook helicopter operations with an external slung load after cable failure

Pavel¹

2010

Aeronaut. j.

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NOMENCLATURE a 0f , a 0r coning angle of front and rear rotor (rad) a 1f , a 1r longitudinal disc-tilt angles of front and rear rotors, positive when the rotor disc plane tilts backwards (rad) b 1f , b 1r lateral disc-tilt angles of front and rear rotor, positive when the disc plane tilts to the azimuth position ψ = 90˚ (rad)blade lift curve slope (rad -1 ) C Q rotor torque coefficient (-) C T,elem,f, C T,elem,r rotor thrust coefficients in blade element theory respectively for front and rear rotor (-) C T,Glau,f, C T,Glau,r rotor thrust coefficients in Glauert formulation respectively for front and rear rotor ( ABSTRACTThe Royal Netherlands Air Force (RNLAF) conducts frequent operations of Chinook helicopters with external slung loads. The normal RNLAF practice is for large external loads to be underslung by means of a two-strop suspension system backed up by a third point of suspension, the so-called 'redundant HUSLE (Helicopter Underslung Load Equipment)' comprising a redundant set of slings which come into action if one of the normal strops fails. The redundant HUSLE is relatively expensive in terms of time and operating costs. The present work has investigated the behaviour of a Chinook helicopter with an underslung load following failure of a front or rear strop, to determine whether the three-point suspension system can be safely replaced by a two-point suspension, eliminating the redundant HUSLE. The paper will demonstrate that although in general the redundant HUSLE results in a less violent helicopter reaction to a cable failure, it does not necessarily guarantee safety. It is concluded that flying with loads up to around two tonnes could be done safely with a two-point suspension system. A novel feature of this analysis of helicopter operations with slung loads is the integrated approach used for simulating pilot-in-the-loop load failures using a full non-linear model.

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“…INTRODUCTION There are various applications for aerial load transportation such as usage in construction, military operations, emergency response, or delivering packages. Load transportation with the cable-suspended load has been studied traditionally for a helicopter [1], [2] or for small unmanned aerial vehicles such as quadrotor UAVs [3], [4], [5].…”

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confidence: 99%

Dynamics and control of quadrotor UAVs transporting a rigid body connected via flexible cables

Goodarzi

Lee

2015

2015 American Control Conference (ACC)

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Abstract-This paper is focused on the dynamics and control of arbitrary number of quadrotor UAVs transporting a rigid body payload. The rigid body payload is connected to quadrotors via flexible cables where each flexible cable is modeled as a system of serially-connected links. It is shown that a coordinate-free form of equations of motion can be derived for arbitrary numbers of quadrotors and links according to Lagrangian mechanics on a manifold. A geometric nonlinear controller is presented to transport the rigid body to a fixed desired position while aligning all of the links along the vertical direction. Numerical results are provided to illustrate the desirable features of the proposed control system.

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Simulation of the Dynamics of Helicopter Slung Load Systems

Cited by 34 publications

References 8 publications

Flight Dynamics of an Articulated Rotor Helicopter with an External Slung Load

Flight Dynamics of an Articulated Rotor Helicopter with an External Slung Load

Investigation of Chinook helicopter operations with an external slung load after cable failure

Dynamics and control of quadrotor UAVs transporting a rigid body connected via flexible cables

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