• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.1
• /
• pp.1-5
• /
• 2002

A common way to design a digital control system is to design an analog controller first and discretize it for digital implemention. In this paper, optimal digital controller design is studied within the framework of sampled -data control theory. In particular, multirate discretization of analog controller is considered using an Η$_2$optimality criterion. Solutions are obtained via multirate H2 optimization with a causality constraint due to the multirate structure. In design example, the comparison of the proposed methods is made with the conventional discretization methods, and demonstrate the superiority of the multirate design method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.10a
• /
• pp.271-274
• /
• 2001

In this paper, optimal digital design is studied within the framework of sampled-data control theory. In particular, multirate discretization of analog controller is considered using an H$_2$optimality criterion. Solutions are obtained via multirate H$_2$optimization with a causality constraint due to the multirate structure. In design example, the comparison of the proposed methods is made with the conventional discretization methods, and demonstrate the superiority of the multirate design method.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.15 no.1
• /
• pp.36-41
• /
• 2005

The smart space is composed of the wire and/or wireless network, multi-sensor-based environment, and many various controllers. For the smart space, this paper presents a new design method of multirate digital decentralized controller using the digital redesign technique. In specific, the proposed method is based on the delta-operator and the multirate sampling and takes the form of the LMIs. To shows the feasibility of the suggested method, the computer simulations for HVAC system are provided.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.1
• /
• pp.13-20
• /
• 2001

Adaptive digital filters with long impulse response such as acoustic echo canceller and active noise controller suffer from slow convergence and computational burden. Subband techniques and multirate signal processing have been recently developed to improve the problem of computational complexity and slow convergence in conventional adaptive filter. Any FIR transfer function can be realized as a serial connection of interpolators followed by subfilters with a sparse impulse response. In this case, each interpolator which is related to the column vector of Hadamard matrix has band-pass magnitude response characteristics shifted uniformly. Subband technique using Hadamard transform and decimation of subband signal to reduce sampling rate are adapted to system modeling and acoustic noise cancellation In this paper, delayless subband structure with nonuniform bandwidth has been proposed to improve the performance of the convergence speed without aliasing due to decimation, where input signal is split into subband one using tree-structured filter bank, and the subband signal is decimated by a decimator to reduce the sampling rate in each channel, then subfilter with sparse impulse response is transformed to full band adaptive filter coefficient using Hadamard transform. It is shown by computer simulations that the proposed method can be adapted to general adaptive filtering.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.11a
• /
• pp.41-46
• /
• 2004

In this paper, we study the stabilization control if an underwater vehicle from its initial posture to its desired one. We assume tint the underwater vehicle has velocity constraint, i.e. it has no velocity component for some direction. Our approach is based on the nonholonomic system which am derived from velocity constraints that cannot integrable. We proposed a control strategy for posture control of the underwater vehicle using multi-rate digital control. The proposed control scheme is applied to the berthing control if an underwater vehicle and verified the effectiveness if control strategy by numerical simulation.