Browse Topic: Biomechanics

Items (58)
In the context of Rotorcraft Pilot Couplings, the biomechanics of the pilot body play a fundamental role in determining the stability of the pilot-vehicle closed loop system. The response of the pilot body is, in turn, inherently stochastic, being a function of pilot biometrics and muscular activation. Coupling the statistical distribution of pilot biomechanical behavior determined in specialized experimental campaign with linear models of the helicopter heave dynamics, an uncertainty propagation procedure is developed, with the aim of estimating the statistical distribution of the stability margins of the closed loop pilot-vehicle system. Results obtained varying the collective lever characteristics, as well as the helicopter model parameters, align well with results obtained previously in deterministic settings. However, the new scheme allows to define quantitative robustness indices.
Zanoni, AndreaMasarati, PierangeloColombo, FrancescaZilletti, MicheleMarchesoli, DavideTalamo, CarmenCassoni, Gianni
ABSTRACT
Colombo, FrancescaKemp, SarahFosco, ErmannoZanoni, AndreaCocco,  AlessandroMarchesoli,  DavideMasarati,  PierangeloTalamo, Carmen
This work presents the results of a piloted flight simulator campaign aimed at measuring biomechanical performance indicators -- upper limbs motion and electromiography of main muscle bundles -- of pilots performing complex, realistic tasks. Ship deck landings performed by a single pilot, flying several helicopter configurations with sea conditions of increasing intensity have been considered. The analysis of the results shows an increase in muscular activity in relation with the increase in task difficulty, in agreement with subjective ratings (Bedford workload scale). The study provided useful indications to improve the corresponding biomechanical simulations, as well as to characterize pilot performance during specific tasks.
Zanoni, AndreaMaisano, GiorgioFrigerio, LorenzoMurawa, MichalZago, MatteoPaolini, RitaQuaranta, GiuseppeMasarati, PierangeloGalli, Manuela
The paper investigates structural coupling problems in tiltrotor aircraft. A detailed tiltrotor model, representative of the Bell XV-15, has been built. The airframe model has been modified with a thinner wing to better reveal structural coupling proneness. A linearized FCS has been introduced to analyze the overall stability on an extended frequency band, ranging from the flight mechanics up to the aeroelastic modes. In addition to the FCS, biomechanical models of the pilot, acting on the power-lever and on the center stick, are included in feedback loop. Overall stability analyses demonstrate that the FCS improves handling qualities although several structural coupling mechanisms arise, in combination with the involuntary pilot's response, reducing flutter clearance. A modified version of the XV-15, using differential collective pitch for yaw control in airplane mode, has been also investigated. This configuration reduces costs and weights although the FCS destabilizes the
Muscarello, Vincenzo
ABSTRACT This work investigates rotorcraft-pilot coupling phenomena in tiltrotors. A detailed tiltrotor model, representative of the Bell-Boeing XV-15, has been built. Biomechanical models of the pilot, acting on the power lever and on the centre stick, are included in feedback loop to define the Pilot-Vehicle System. Pilot-Assisted Oscillation phenomena are investigated on the overall conversion corridor using Nyquist's criterion. Pilot-in-the-loop analyses demonstrate that a critical parameter is detected in the vertical fins geometry. Due to an asymmetric flaperons deflection the wing's wake impacts on the vertical fins, producing a side force. The pulsating tail-side-force makes the fuselage to yaw and excites the asymmetric wing chord mode coupled with the lateral pilot's biomechanics, leading to a reduction, or even a loss, of stability. No unstable event is detected about the longitudinal direction. Conversely, a resonance between the pilot's biomechanics and the aircraft poorly
Colombo, FrancescaMuscarello, VincenzoQuaranta, GiuseppeMasarati, Pierangelo
The paper investigates the basic mechanism of aeroservoelastic Pilot Assisted Oscillation phenomenon (PAO) about the roll axis due to the interaction with the pilot's arm biomechanics. The motivation stems from the observation that a rotor imbalance may occur as a consequence of rotor cyclic lead-lag modes excitation. The instability mechanism is analogous to the 'air resonance' phenomenon, in which the pilot's involuntary action plays the role of the AFCS. Using robust stability analysis, the paper demonstrates that, in particular, the introduction of a gain and a time-delay between the stick motion and the servoactuator displacements may reduce the gain and phase margins of the pilotvehicle system. The mechanism of instability proves that the pilot biodynamics is participating to the destabilization of the system by inputting energy directly into the flapping mode. This destabilizes the airframe roll motion which, in turn, causes lag motion imbalance. It is found that, depending on
Masarati, PierangeloTod, GeorgesPavel, MarilenaMuscarello, VincenzoQuaranta, GiuseppeMalburet, François
ABSTRACT This work proposes a helicopter pilot model identified from experimental results obtained in piloted simulation flight tests. The tests were originally designed to verify predicted unstable pilot-vehicle systems. The results have been further analyzed using methods for the detection of pilot induced oscillation that are available from the literature. The results show that a pilot-assisted oscillation event occurring in one configuration is characterized by a change of biomechanical properties of the pilot. It is conjectured that such change is triggered by a change in the task of the pilot induced by the specific maneuver that is requested of the pilots in the tests.
Jump, MichaelMarguerettaz, PaoloMasarati, PierangeloLu, LinghaiGuglieri, GiorgioMuscarello, VincenzoQuaranta, Giuseppe
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