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A novel trajectory generation and control architecture for fully autonomous autorotative flare that combines rapid path generation with model-based control is proposed. The trajectory generation component uses optical Tau theory to compute flare trajectories for both longitudinal and vertical speed. These flare trajectories are tracked using a nonlinear dynamic inversion (NDI) control law. One convenient feature of NDI is that it inverts the plant model in its feedback linearization loop, which eliminates the need for gain scheduling. However, the plant model used for feedback linearization still needs to be scheduled with the flight condition. This key aspect is leveraged to derive a control law that is scheduled with linearized models of the rotorcraft flight dynamics obtained in steady-state autorotation, while relying on a single set of gains. Computer simulations are used to demonstrate that the NDI control law is able to successfully execute autorotative flare in the UH-60 aircraft. Autonomous flare trajectories are compared to piloted simulation data to assess similarities and discrepancies between piloted and automatic control approaches. Trade studies examine which combinations of downrange distances and altitudes at flare initiation result in successful autorotative landings. [ABSTRACT FROM AUTHOR]

The time-to-contact t theory posits that purposeful actions can be conducted by coupling the actor's motion onto the so-called τ guides generated internally by their central nervous system. Although significant advances have been made in the application of t for flight control purposes, little research has been conducted to investigate how pilots are able to adapt their τ-guidance strategy to different aircraft dynamics, or how a τ-guide-based pilot-aircraft model might be used to represent control behavior. This paper reports on the development of such a model to characterize the adaptation of pilot guidance to variations in aircraft dynamics using data obtained from a clinical pilot-in-the-loop flight simulation experiment. The results indicate that pilots tend to maintain a constant coupling between the dynamic system's motion and the r guide across a range of different configuration parameters. Simultaneously, the pilot modulates the guidance maneuver period to adapt to these different aircraft dynamics that result in changes in workload. Modeling the complete pilot stabilization and guidance function as a regulator plus inverter yields good comparative results between the pilot-aircraft model and simulator trajectory data, and it supports the hypothesis that the following r-based guidance strategies suppress an aircraft's natural dynamics. [ABSTRACT FROM AUTHOR]

With recent increased interest in autonomous vehicles and the associated technology, the prospect of realizing a personal aerial vehicle seems closer than ever. However, there is likely to be a continued requirement for any occupant of an air vehicle to be comfortable with both the automated portions of the flight and their ability to take manual control as and when required. This paper, using the approach to landing as an example maneuver, examines what a comfortable trajectory for personal aerial vehicle occupants might look like. Based upon simulated flight data, a "natural" flight trajectory is designed and then compared to constant deceleration and constant optic flow descent profdes. It is found that personal aerial vehicle occupants with limited flight training and no artificial guidance follow the same longitudinal trajectory as has been found for professionally trained helicopter pilots. Further, the final stages of the approach to hover can be well described using the Tau theory. For automatic flight, personal aerial vehicle occupants prefer a constant deceleration profile. For approaches flown manually, the newly designed natural profile is preferred. [ABSTRACT FROM AUTHOR]

This paper presents the development of a multiloop pilot model for use in boundary-triggered pilot-induced oscillation investigations. In doing so, the point-tracking and boundary-avoidance elements of the pilot control strategy are assumed to act simultaneously for a point-tracking-dominant task during a boundary-avoidance tracking event. The theoretical analysis indicates that the essence of the boundary-avoidance tracking phenomenon consists of an additional requirement for the pilot to provide lead equalization as the boundary is approached as the task transitions from a full-attention point-tracking task to both a point-tracking and boundary-avoidance task. This process leads to a narrower open-loop system bandwidth and a larger tracking error, or the triggering of a pilot-induced oscillation. It is also found that the severity of the boundary-avoidance influence can be reduced by including the effects of vestibular and proprioceptive cues into the model. The boundary-avoidance tracking pilot model exhibits pilot-vehicle responses that are consistent with those observed in a piloted-simulation study and can therefore be considered to be representative of pilot activity. Consideration of the results in the round indicates that the boundary-triggered pilot-induced oscillation can be categorized as Category III pilot-induced oscillation within the existing recognized taxonomy. [ABSTRACT FROM AUTHOR]

The investigation of motion guidance and its subsequent application using tau (T) theory relies on the accurate calculation of the coupling term between the T (time to contact) of the motion and the appropriate r guide. However, the traditional approach for this calculation can be numerically unstable, requires experience and skill to execute in a meaningful manner, is sensitive to the data selected, and has limited application when the motion information is incomplete or deviates from the ideal. To deal with these issues, a new approach, based on positive wavelet analysis, is proposed in this paper. The mother wavelet is constructed using the desired r-guide shapes, with its scale considered to be defined by the maneuver period. The scale and time information of interest are found by searching for the best local correlation within the whitened original signal. An inverse dewhitening process is then used to reconstruct an approximation to the original motion signal. The adequacy of the positive wavelet method has been demonstrated using data obtained from piloted simulation test campaigns. The results show that the approach is not only feasible, but it has better numerical stability, reliability, enhanced performance, and wider applicability than those that have been used to date. [ABSTRACT FROM AUTHOR]

Pilot–vehicle interaction represents a critical aspect of aircraft design. Very low-frequency, voluntary although unintentional interaction has been extensively investigated in fixed and rotary wing aeromechanics. Higher frequency, involuntary and thus passive interaction received similar attention in fixed wing aeromechanics, but not as much for rotary wing. The results of an experimental campaign for the characterization of the passive behaviour of rotorcraft pilots' biomechanics are presented. A flight simulator has been used to excite human subjects. The accelerations of their limbs and the motion induced by the vibrations of the limbs in the control inceptors have been recorded. The vertical, longitudinal and lateral directions have been independently excited, while measuring the motion of the arm directly involved in the control inceptor mostly affected by motion in each direction, namely the left and the right arms for the collective and the cyclic sticks, respectively. The frequency domain response has been evaluated; resulting noteworthy behaviour is discussed, addressing its relevance in modelling the passive behaviour of pilots within the bioaeroservoelastic rotorcraft analysis. The measurements of human body impedance, under realistic cockpit motion, are used to identify the direct transfer functions between the motion of the seat and the controls inadvertently fed back into the rotorcraft. [ABSTRACT FROM AUTHOR]