Minimal-Complexity Helicopter Math Models
Heffley Engineering has applied RotorGen2 minimal-complexity models to a
variety of helicopters.
modeling is based on a scheme outlined in an Army-sponsored program more than 20
years ago (Manudyne Report 83-2-3).
The original concept was to devise
a helicopter math model that embodies the first-principles of rotary-wing
aerodynamics while requiring a minimum of model parameters and computing power.
The main objectives were to
minimize computational delay (frame time), to simplify adaptation to a specific
aircraft, and to minimize the engineering labor in implementation and checkout.
RotorGen was an
implementation of the original minimal-complexity model applied to a series of
handling-qualities studies by the U.S. Army on the NASA Ames VMS large-amplitude
motion simulator facility.
RotorGen2 is a
second-generation development of the original "minimal-complexity" math model
The advantages of RotorGen2
is its implementation in Matlab and Simulink form as well as C++ code, its capability to run in the
TPV modeling environment, and the array of RHE development tools for adapting
RotorGen2 to specific rotary-wing vehicles.
Because RotorGen2 depends
on analytic functions to describe aerodynamics, it can be molded to match a
minimal amount of available data, much of which may be basic geometrical and
RotorGen2 provides a simulation
solution for many applications requiring basic helicopter dynamical modes
without higher-order/high-frequency blade dynamics.
RotorGen2 provides correct
non-linear behavior over a large range of airspeeds and wing-body aerodynamics
for the full range of angle of attack and sideslip.
While the basic RotorGen2 model
models only the normal working state, it can be augmented to include the
autorotation (windmill) state.
Other effects can be added,
including higher-order tip-path-plane dynamics, ground effect, ground contact,
blade stall onset, etc.
RotorGen2 provides the user with
control over the tradeoff between complexity and model accuracy, hence,
engineering cost, computer performance, and simulator fidelity.
Updated 1 March 2011