We present a technique for measuring, controlling, and stabilizing the attitude of a UAV by using a camera to monitor the visual horizon. A vision-based algorithm incorporating color and intensity information is used to detect the horizon by segmenting the ground from the sky. The attitude of the aircraft is then measured using the position, shape, and orientation of the horizon profile in the ...

In this paper an observer-controller structure for attitude synchronization of a satellite formation is presented. The design applies methods from mechanical synchronization to design a nonlinear observer and controller for satellites actuated by means of reaction wheels and magnetic torquers. In this approach one satellite is defined as the leader of the formation, while the rest are defined a...

This paper addresses the problem of how to coordinate the spatial motion of individual agents in a multi-agent system in such a way that the distance between any two agents is maintained at a constant value (but not stabilized) throughout the evolution of the system while simultaneously rotating the formation of agents to a pre-set reference attitude. We propose a distributed control law based ...

The theoretical challenge involved in the operation of VTOL UAVs is often divided into two main problems. The first problem involves the development of an estimation scheme which can accurately recover the orientation, or angular position, of the aircraft. The second problem involves the development of algorithms which can be used to reliably control the orientation and/or the position of the v...

Quadrotor is a widely used aircraft now and be with the nonlinear, uncertain characteristics. Because of requirement on high attitude stability the attitude control system of quadrotor needs to be well designed. Firstly the movement pattern and working principle of the quadrotor are analyzed. Then the hardware schematic diagram of attitude control system is designed which includes several senso...

We develop a non-linear tracking control law to be applied to formation flying spacecraft. Each spacecraft in the formation is modeled as a rigid body with N axisymmetric wheels controlled by axial torques, and the kinematics are represented by Modified Rodriques Parameters (MRPs). The paper first derives the open-loop reference attitude, rate, and acceleration commands for tracking a moving ob...