Voluntary Pilot Action Through Biodynamics for Helicopter Flight Dynamics Simulation

This work presents the integration of detailed models of a pilot controlling a helicopter along the heave axis through the collective control inceptor. The action on the control inceptor is produced through a biomechanical model of the pilot’s limbs, by commanding the activation of the related muscle bundles. Such activation, in turn, is determined by defining the muscle elongations required to move the control inceptor in order to obtain the control of the vehicle according to a high-level model of the voluntary action of the pilot acting as a regulator for the vehicle. The biomechanical model of the pilot’s limbs and the aeromechanical model of the helicopter are implemented in a general-purpose multibody simulation. The helicopter model, the biomechanical model of the pilot’s limbs, the cognitive model of the pilot, and their integration are discussed. The integrated model is applied to the simulation of simple, yet representative, mission task elements

Projection continuation for minimal coordinate set formulation and singularity detection of redundantly constrained system dynamics

The formulation of (possibly redundantly) constrained system dynamics using coordinate projection onto a subspace locally tangent to the constraint manifold is revisited using the QR factorization of the constraint Jacobian matrix, using column pivoting to identify a suitable subspace, possibly detect any singular configurations that may arise, and extract it. The evolution of the QR factorization is integrated along with that of the constraint Jacobian matrix as the solution evolves, generalizing to redundant constraints a recently proposed true continuation algorithm that tracks the evolution of the subspace of independent coordinates. The resulting subspace does not visibly affect the quality of the solution, as it is merely a recombination of that resulting from the blind application of the QR factorization but avoids the artificial algorithmic irregularities or discontinuities in the generalized velocities that could otherwise result from arbitrary reparameterizations of the coordinate set, and identifies and discriminates any further possible motions that arise at singular configurations. The characteristics of the proposed subspace evolution approach are exemplified by solving simple problems with incremental levels of redundancy and singularity orders

Helicopter Rotor Sailing by Non-Smooth Dynamics Co-Simulation

This paper presents the application of a co-simulation approach for the simulation of frictional contact in general-purpose multibody dynamics to a rotorcraft dynamics problem. The proposed approach is based on the co-simulation of a main problem, which is described and solved as a set of differential algebraic equations, with a subproblem that is characterized by nonsmooth dynamics events and solved using a timestepping technique. The implementation and validation of the formulation is presented. The method is applied to the analysis of the droop and anti-flap contacts of helicopter rotor blades. Simulations focusing on the problem of blade sailing are conducted to understand the behavior and assess the validity of the method. For this purpose, the results obtained using a contact model based on Hertzian reaction forces at the interface are compared with those of the proposed approach

Helicopter Kit

A kit (1) for a helicopter (2) is described, the helicopter (2) comprising a fuselage (3) and a rotor (4); the kit (1) comprises at least one device (15) adapted to dampen the vibrations transmitted from the rotor (4) to the fuselage (2) and to be interposed between the fuselage (2) and the rotor (4); the device (15), in turn, comprises a first threaded element (21; 20) operatively connectable to the rotor (4) and adapted to, in use, vibrate parallel to a first axis (B); a second threaded element (20; 21) operatively connectable to the fuselage (4) and operatively connected to the first threaded element (21; 20) so as to, in use, rotationally vibrate about the first axis (B); and a plurality of threaded rollers (22), which are screwed on the first and second threaded elements (21, 20; 20, 21); the rollers (22) being rotatable about their respective second axes (C) parallel to and separate from the first axis (B) with respect to the first and second threaded elements (21, 20); the rollers (22) are also rotatable about the first axis (B) with respect to the first threaded element (21; 20) and the second threaded element (20; 21)

Rotor For A Hover-Capable Aircraft And Method For Containment Of Vibrations Transmitted To The Mast Of A Rotor Of A Hover-Capable Aircraft

A rotor (3) for a hover-capable aircraft is described, comprising: a hub (5) rotatable about an axis (A) and, in turn, comprising a plurality of blades (9); a mast (6) connectable to a drive member of the aircraft (1) and operatively connected to the hub (5) to drive the hub (5) in rotation about the axis (A); and damping means (15) for damping vibrations transmitted to the mast (6), which comprise a mass (17) designed to oscillate in a plane transversal to the axis (A) so as to contain flexural vibrations of the mast (6) generated by rotation of the blades (9); the damping means (15) also comprise elastic means (30) having a desired stiffness along the axis (A) and operatively connected to the mass (17) to contain vibration of the mast (6) along the axis (A)