This page presents the latest flight tests of a new linear robust controller for
the Carnegie Mellon University Yamaha R-50 Robotic Helicopter.
I
have designed the controller
using a high-order linear model of the R-50
extracted at hover from MOSCA
(MOdelling for Flight Simulation and Control
Analysis) small-scale helicopter non-linear simulation model.
Before flying,
the controller went through extensive non-linear flight simulation
tests. The highly accurate simulation provided by MOSCA
allowed to achieve the results presented here, after only 2 preliminary
flight tests of 20 minutes each.
The maneuvers were all flown with the hover controller.
This controller consists of 1 multivariable (MIMO) inner loop for
stabilization and
4 separate (SISO) guidance loops for velocity and position control.
For every maneuver there is a description and 2 different
videos. The first video is from a Mini-DV camera. The second is a playback
of the flight data recorded during the same maneuver; that is,
it is not a simulation.
The animation in the second video is created with
an inteface designed to read and playback flight data for better
analysis. The graphical inteface also shows the desired
trajectory.
Although the trajectory-following performace during these maneuvers
is remarkable (no other robotic helicopter having ever achieved this level
of tracking at similar speeds),
the main goal of these flight tests is to show the robustness of the
hover controller; the trajectories are in fact not optimal in any
sense (e.g., there is no prescribed transition phase between straight and turning flight)
For the square maneuver there is only the animation video.
The helicopter starts from hover and tries
to mantain constant altitude and yaw angle while
executing 4 horizontal steps of 20.0 m: (1) 20.0 m forward (positive x step),
(2) 20.0 m to the right (positive y step), (3) 20.0 m
backward (x negative step), (4) 20.0 m to the left (y
negative step). The ending point of the trajectory coincides
with the starting one.
Forward Turn
The helicopter starts at hover. Then it accelerates forward
up to to a velocity of 6 m/s trying to stay on a straight line till
the turn is commanded. The turn trajectory is a
circle of 10 m radius. The helicopter flies the
turn mantaining 6 m/s velocity and constant altitude.
Backward Turn
The helicopter starts at hover. Then it accelerates backward
up to to a velocity of 5 m/s trying to stay on a straight line till
the turn is commanded. The turn trajectory is a
circle of 10 m radius. The helicopter flies the
turn mantaining 5 m/s velocity and constant altitude.
Nose-Out Pirouette
The helicopter starts at hover. Then it accelerates laterally
up to to a velocity of 4 m/s trying to stay on a straight line till
the turn is commanded. The turn trajectory is a
circle of 10 m radius. The helicopter flies the
turn mantaining 4 m/s velocity and constant altitude.
The helicopter's tail points always towards the center of the circle.
Nose-In Pirouette
The helicopter starts at hover. Then it accelerates laterally
up to to a velocity of 4 m/s trying to stay on a straight line till
the turn is commanded. The turn trajectory is a
circle of 10 m radius. The helicopter flies the
turn mantaining 4 m/s velocity and constant altitude.
The helicopter's nose points always towards the center of the circle.