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Among many nominated papers, three technical papers and an annual review have been published in this volume. However, there are excellent papers in the unselected ones, some of them, are summarized hereafter for readers’ reference. A Study on Automatic Tuning of PID Governor for Marine Diesel Engine By Toshihiko Nakatani, Kohei Ohtsu, Toshiyuki Hotta, Tadatsugi Okazaki The most of governors for marine diesel engine is still designed based on the classical PID control theory. Various methods have been proposed for tuning PID parameters. One of the conventional methods often used in the gain tuning is the Ziegler Nichols ultimate method. There are some problems, however, when this conventional method is applied to operating marine diesel engine as follows; 1) It is not always safe technique because a proportional gain in this method is gradually increased until the system reaches a critical state. 2) The success of the technique depends largely on operator’s experience. To solve these problems, it is necessary to adopt some automatic gain tuning technique, which does not give great influences on the system and can be easily implemented without danger. In this paper, a simple and a safe automatic gain tuning method using relay control is provided for diesel engine governor system with PID control law. In this method, a limit cycle with small amplitude is occurred, at the beginning, through a fuel oil pump rack, and then the amplitude and the period of the limit cycle are observed. Since the two quantities obtained under such limit cycle equivalently correspond to those by the Ziegler Nichols ultimate method, these are utilizable as the parameters for obtaining the optimal gains recommended by Ziegler Nichols. This technique is applied to the governor system of a small training ship, full scale experiments were carried out and the results of the experiments are discussed. —Reprinted from Journal of the M.E.S.J., Vol. 32, No. 10—

This paper has two objects, one is to present a new computer control system for a digital control system (DDC) instead of a conventional governor for the main diesel engine and another is to discuss a control law based on the discrete type of the PID controller.In general, in the case of operating the diesel engine, the governor is indespensable because of its unstable control characteristics, and has played very important roll so far. But, with year there have been a lot of requests to the engine governor, for example, how to overcome the propeller racing, how to decrease fuel oil consumption and so on. In particular, the propeller racing in the rough sea has been a very serious problem in the ocean going ship, because this phenomenon breaks down the propulsion system and then decrease its reliability. Consequently, for studying on such serious and difficult problems, we constructed a new DDC system for the marine systems at the same time when the training ship“SHIOJIMARU”was built up in 1988.Next, we investigate the characteristics of on the discrete type of the PID theory from the viewpoint of practical techniques. More, we propose our new control method for the speed control of the diesel engine and then on the basis of our new method, we provide the outline of software used in our sea test.Finally, the DDC based on the computer system is proved to be very useful system by illustrating our experimental results.

In this paper we describe the outline of an instrumentation system installed in“Shiojimaru”built for Tokyo University of Mercantile Marine as the trainning ship in 1987, and its actual ship test results over past two years. First we give the concepts and construction of the system for instrumentation which are classified into two groups; one group is a system for ordinary navigation and another is for study and development of the ship and its system. Next, in order to show an composed control system concretely, we pick up the engine speed control system as an example from various control systems and then illustrate the new system composed of computers, electronic devices, local area network (LAN) system and so on. Finally, we show our experimental results obtained by actual ship tests, for example, the results of the main engine speed and the Z test controlled by a direct digital control (DDC) .