• Journal of Institute of Control, Robotics and Systems
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• v.14 no.12
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• pp.1260-1265
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• 2008

This study deals with modeling and flight control of quadrotor type (QRT) unmanned aerial vehicles (UAVs). Rigorous dynamic model of a QRT UAV is obtained both in reference and body frame coordinate systems. A disturbance observer (DOB) based controller using the derived dynamic models is also proposed for robust hovering control. The control input induced by DOB is helpful to use simple equations of motion satisfying accurate derived dynamics. The experimental results show the performance of the proposed control algorithm.

• Smart Structures and Systems
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• v.14 no.3
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• pp.327-345
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• 2014

This paper presents a composite control strategy for the active suppression of vibration due to the unknown disturbances, such as external excitation, harmonic effects and control spillover, as well as high-frequency accelerometer measurement noise in the all-clamped stiffened plate. The proposed composite control action based on the modal approach, consists of two contributions including feedback part and feedforward part. The feedback part is the well-known PID controller, which is widely used to increase the structure damping and improve its dynamic performance close to the resonance frequencies. In order to get better performance for vibration suppression, the weight matrixes is optimized by chaos sequence. Then an improved disturbance observer (IDOB) as the feedforward compensation part is developed to enhance the vibration suppression performance of PID under various disturbances and uncertainties. The proposed IDOB can simultaneously estimate the various disturbances dynamically as well as measurement noise acting on the system and suppress them by feedforward compensation design. A rigorous analysis is also given to show why the IDOB can effectively suppress the unknown disturbances and measurement noise. In order to verify the proposed composite control algorithm (IDOB-PID), the dSPACE real-time simulation platform is used and an experimental platform for the all-clamped stiffened plate active vibration control system is set up. The experimental results demonstrate the effectiveness, practicality and strong anti-disturbances ability of the proposed control strategy.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.1 s.24
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• pp.50-59
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• 2006

Lately, there exist growing demands for the use of CTAs(Cased Telescoped Ammunitions) to increase the firepower of mid-calibre automatic guns despite spatial limitations of armament. In this paper, for automatic CTA guns a rotating chamber mechanism is designed based on parallel index concept. Via dynamic simulations it proves capable of smooth operation even at as high a firing rate as 200spm. Subsequently, motor controllers are synthesized to drive the chamber at any constant speed and also to control positions in the presence of large disturbances caused by the intermittently-rotating load. It is remarkable that we successfully adopted a disturbance observer to treat disturbances only with a moderate bandwidth of the closed-loop system.