Xin‐long Chen and Di Yang
The purpose of this paper is to examine the attitude control problem of a certain and big flexible satellite with unmodeled dynamics and unknown bounded disturbances and control…
Abstract
Purpose
The purpose of this paper is to examine the attitude control problem of a certain and big flexible satellite with unmodeled dynamics and unknown bounded disturbances and control input saturation; and to present a design method of robust adaptive controllers (RACs).
Design/methodology/approach
First, using the Lyapunov stability theory, it is shown that the proposed adaptive controller can guarantee the stability of the nonlinear system. Then, the parameters regulation method of the RAC is introduced. Finally, an RAC is designed for the object satellite model consisted of all the error‐source models.
Findings
The simulation results are compared with other results that are derived by using the typical PID controller. It is proved that the designed RAC has some properties of quickly response, high steady‐state precision and strong robustness.
Originality/value
The paper is of value in presenting a design method of RACs aiming at the object satellite with uncertainties and control input saturation.
Details
Keywords
Abstract
Purpose
The purpose of this paper is to develop a monocular visual measurement system for autonomous aerial refueling (AAR) for unmanned aerial vehicle, which can process images from an infrared camera to estimate the pose of the drogue in the tanker with high accuracy and real-time performance.
Design/methodology/approach
Methods and techniques for marker detection, feature matching and pose estimation have been designed and implemented in the visual measurement system.
Findings
The simple blob detection (SBD) method is adopted, which outperforms the Laplacian of Gaussian method. And a novel noise-elimination algorithm is proposed for excluding the noise points. Besides, a novel feature matching algorithm based on perspective transformation is proposed. Comparative experimental results indicated the rapidity and effectiveness of the proposed methods.
Practical implications
The visual measurement system developed in this paper can be applied to estimate the pose of the drogue with a fast speed and high accuracy and it is a feasible measurement strategy which will considerably increase the autonomy and reliability for AAR.
Originality/value
The SBD method is used to detect the features and a novel noise-elimination algorithm is proposed. Besides, a novel feature matching algorithm based on perspective transformation is proposed which is robust and accurate.