Proceedings Article | 4 February 2013
KEYWORDS: Sensors, Control systems, Detection and tracking algorithms, Cameras, Unmanned aerial vehicles, Global Positioning System, Target detection, Image segmentation, RGB color model, Sensor fusion
In recent years, autonomous, micro-unmanned aerial vehicles (micro-UAVs), or more specifically hovering micro-
UAVs, have proven suitable for many promising applications such as unknown environment exploration and search
and rescue operations. The early versions of UAVs had no on-board control capabilities, and were difficult for
manual control from a ground station. Many UAVs now are equipped with on-board control systems that reduce the
amount of control required from the ground-station operator. However, the limitations on payload, power
consumption and control without human interference remain the biggest challenges.
This paper proposes to use a smartphone as the sole computational device to stabilize and control a quad-rotor.
The goal is to use the readily available sensors in a smartphone such as the GPS, the accelerometer, the rate-gyros,
and the camera to support vision-related tasks such as flight stabilization, estimation of the height above ground,
target tracking, obstacle detection, and surveillance. We use a quad-rotor platform that has been built in the Robotic
Vision Lab at Brigham Young University for our development and experiments. An Android smartphone is
connected through the USB port to an external hardware that has a microprocessor and circuitries to generate pulse-width
modulation signals to control the brushless servomotors on the quad-rotor. The high-resolution camera on the
smartphone is used to detect and track features to maintain a desired altitude level. The vision algorithms
implemented include template matching, Harris feature detector, RANSAC similarity-constrained homography, and
color segmentation. Other sensors are used to control yaw, pitch, and roll of the quad-rotor. This smartphone-based
system is able to stabilize and control micro-UAVs and is ideal for micro-UAVs that have size, weight, and power
limitations.
