An expert system for diagnosing faults in the power train of a twin-engine gas turbine helicopter has been developed. The system, designated HELIX (HELicopter Integrated expert), performs diagnostic reasoning based on a hierarchical qualitative model representing the major power train components and the physical principles that govern their interaction. The approach represents a promising techn...

Airborne geophysical systems have been in use since 1943 (Hildenbrand et al., 1990). These systems used airborne magnetometers for submarine detection and geophysical mapping. Airborne electromagnetic systems were introduced in the 1950s (Barringer et al., 1990) for mineral exploration. These early magnetic and electromagnetic systems were mounted on fixed wing aircraft. In the 1960s helicopter...

Autonomous outdoor quad-rotor helicopters increasingly attract the attention of potential researchers. Several structures and configurations have been developed to allow 3D movements. The quadrotor helicopter is made of a rigid cross frame equipped with four rotors. The autonomous quad-rotor architecture has been chosen for this research for its low dimension, good manoeuvrability, simple mecha...

In this paper, identification of lateral and longitudinal dynamics of helicopter using flight data is presented. Neural networks with linear filter also known as Narendra's model and recurrent neural networks with intemal memory (Memory Neuron Networks) are used for the purpose. These networks are used for identifying the rate and attitude response of the helicopter to a given longitudinal cycl...

Helicopters in flight are unstable, much like an inverse pendulum, and hovering at one spot requires the pilot to do a considerable amount of active control. It is assumed that they do not only use visual information, but also vestibular and somatosensory cues. To test this hypothesis, we measured helicopter hovering performance of human subjects in a simulator. Which senses do pilots use to st...

In this paper, combined attitude control of an underactuated helicopter experimental system is considered. The controlled helicopter experimental system has two inputs and three outputs, namely, this system is underactuated. The combined attitude controller includes a nonlinear MIMO controller based on adaptive sliding mode control and non-adaptive nonlinear controllers. Control system stabilit...

Formally posed in 1965, the problem of optimal attitude estimation from vector measurements has been a hot topic of research in the aerospace community. This paper provides a survey of open source quadrotor helicopter autopilots that demonstrates that the Unmanned Aerial Vehicle community has largely ignored the optimal attitude estimation work to date. Furthermore, the effectiveness of a quadr...

Vortex interactions in helicopter rotor wakes are visualized using enhanced flow visualization techniques, which in turn play a crucial role in understanding the dynamics of these complex flows. Iso-surfaces are clipped in a 3D volume to reduce visual clutter. Flow textures are improved to highlight vortical flow structure and vortex-wake interactions. These visualization techniques are applied...

Airflow hazards such as turbulence, vortices, or low-level wind shear can pose a threat to landing aircraft and are especially dangerous to helicopters. Because pilots usually cannot see airflow, they may be unaware of the extent of the hazard. We have developed a prototype airflow hazard visual display for use in helicopter cockpits to alleviate this problem. We report on the results of a prel...

The Helicopter Adaptive Aircraft (HADA) is a morphing aircraft which is able to take-off as a helicopter and, when in forward flight, unfold the wings that are hidden under the fuselage, and transfer the power from the main rotor to a propeller, thus morphing from a helicopter to an airplane. In this process, the reliable folding and unfolding of the wings is critical, since a failure may deter...