南 裕樹

Networked control has been studied by many researchers in recent years. This paper proposes a new system structure of the networked control systems. The evaluation system is presented to find the performance degradation caused by the communication channels. The proposed system has high degree of freedom for design and is not cumbersome structure. The effectiveness of the proposed structure is illustrated by numerical simulations.

This paper focuses on distributed LED lighting systems composed of multiple LED lights, and addresses the lighting pattern design problem for the systems. In the design problem, the dynamic lighting, which is PWM type lighting, is considered, and the lighting patterns are determined such that a supplying illuminance distribution is similar to a desired one. In this paper, we first propose a distributed optimization algorithm for determining lighting patterns. Then, we develop an experimental equipment with 25 LED units. Finally, we verify the effectiveness of our algorithm and the fault-tolerance of the distributed lighting system through some control experiments.

In this paper, a novel quantizer design method for discrete-valued input control is proposed. The key technique of the proposed method is a serial decomposition of systems whose input is discrete-valued. More specifically, we perform an inner-outer like factorization, and a dynamic quantizer is analytically derived for the outer part. The proposed method enables us to design stable dynamic quantizers for non-minimum phase systems and fixed-order dynamic quantizers.

For the control of mechanical systems including discrete-valued devices such as discrete-level actuators and communication encoders, one of the promising approaches is to utilize dynamic quantizers. Here, the dynamic quantizer is a device which converts continuous-valued signals into discrete-valued ones depending on the past signal data. This paper focuses on a dynamic quantizer design problem which is to find a quantizer such that the output behavior of systems with quantizers is similar to that of ideal systems without quantizers. In this paper, we first formulate a design problem of fixed-order dynamic quantizers under several constraint conditions such as stability of quantizer, control input saturation, and pole assignment. Then, for getting a solution to the problem, we present an easy-to-use quantizer design method based on particle swarm optimization (PSO) which is a swarm intelligence technique and is one of the evolutionary computation algorithms. Finally, it is verified that the PSO based method gives satisfactory fixed-order dynamic quantizers through several numerical examples with a cart positioning system and an unstable mechanical system. Further we conclude that the proposed method could be an useful tool for the design of dynamic quantizers.

The Smart Grid is a novel concept which integrates the power grid and the information-communication technology in order to increase the reliability of electricity and the efficiency of energy usage. Toward developing the smart grid, this paper focuses on the control of distributed generation networks composed of multiple generators such as gas-engines and gas-turbines. In this paper, we first formulate an operation mode control problem which is to determine ON/OFF modes of the generators subject to the balance of supply and demand. Then, as a solution to the problem, this paper proposes a simple and useful distributed control algorithm based on the idea of the halftoning which is one of image processing techniques. Finally, the effectiveness of the proposed method by several numerical simulations is evaluated.

This paper addresses a problem of designing decentralized sigma-delta modulators for quantized control, i.e., feedback control subject to quantized signal constraints. The sigma-delta modulators to be considered here have a limited information structure so as to be implemented in a decentralized manner, which poses a challenging design problem. We first analytically derive a solution to the problem such that the resulting quantized feedback system optimally approximates the corresponding unquantized system. Next, the performance is demonstrated by a numerical simulation and an experiment for the stabilization problem of a seesaw-cart system.

This paper presents a software tool, entitled ODQLab, to design dynamic quantizers for discrete-valued input control. ODQLab is a Matlab-based graphical tool, which enables us to obtain and verify dynamic quantizers without the knowledge of any sophisticated design theory. In this paper, we introduce the software tool with the underlying theory. Its effectiveness is demonstrated by design examples and experimental evaluations.