Control of a helicopter is complex, and includes cross coupling of forces and balancing of forces. While sophisticated and advanced controllers can achieve stable control, good mechanical design can reduce the problems and hence make tuning the control loops easier. In this paper, we argue that a coaxial-rotor design solves a number of problems that make control of a four-rotor helicopter diffi...

A slowed-rotor compound helicopter has been synthesized using the NASA Design and Analysis of Rotorcraft (NDARC) conceptual design software. An overview of the design process and the capabilities ofNDARC are presented. The benefits of trading rotor speed, wing-rotor lift share, and trim strategies are presented for an example set of sizing conditions and missions. NOMENCLATURE Acronyms DGW Desi...

The goal of the European project muFly is to build a fully autonomous micro helicopter, which is comparable to a small bird in size and mass. The rigorous size and mass constraints infer various problems related to energy efficiency, flight stability and overall system design. In this research, aerodynamics and flight dynamics are investigated experimentally to gather information for the design...

This paper deals with model predictive control (MPC) approach for a 2 DOF (degree of freedom) helicopter. The main objective is to stabilize beam of the 2DOF helicopter with respect to pitch and yaw angles. Development of controller for 2DOF helicopter is challenging because of its coupling effects between two axes and also due to its highly nonlinear characteristics. An accurate model of the s...

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...

Received Sep 9, 2013 Revised Feb 2, 2014 Accepted Feb 26, 2014 This paper describes the actual flight movements of electric helicopters and how to implement a disaster area monitoring system using electric ground vehicles and electric helicopters. A quad-rotor helicopter and a hex-rotor helicopter were used in the proposed system, specifically, the AR.Drone 2.0 and the DJI Innovations frame kit...

This paper summarizes a method that solves both the three dimensional thin-layer Navier-Stokes equations and the Euler equations using overset structured and solution adaptive unstructured grids with applications to helicopter rotor fiowfields. The overset structured grids use an implicit finite-difference method to solve the thin-layer Navier-Stokes/Euler equations while the unstructured grid ...

Rotor blade injuries are an inherent hazard of helicopter operations. To determine the recent incidence of rotor blade injuries in the U.S. Army, a review of accident records (1972-91) was conducted. Crash-related injuries were not included. During the study period, there were 24 blade strike injuries (12 involving the main rotor), 11 (46%) of which were fatal. Comparison with previous reports ...

The advancement on Wireless Sensor Networks for vibration monitoring presents important possibilities for helicopter rotor health and usage monitoring. While main rotor blades account for the main source of lift for helicopters, rotor induced vibration establishes an important source for understanding the rotor performance and blade condition. A discussion on the dual character of blades as rot...

We present control methods for an autonomous four-rotor helicopter, called a quadrotor, using visual feedback as the primary sensor. The vision system uses a ground camera to estimate the pose (position and orientation) of the helicopter. Two methods of control are studied one using a series of mode-based, feedback linearizing controllers, and the other using a backstepping-like control law. Va...