DEVELOPMENT OF A VISUAL-AID TEACHING MATERIAL LINKED TO A SHIP HANDLING SIMULATOR
Kinzo INOUE (Kobe University of Mercantile Marine, Japan)
Hideo USUI (Kobe University of Mercantile Marine, Japan)
Rong MA (Kobe University of Mercantile Marine, Japan)
Abstract: The fundamental knowledge and understanding about ship-handling are indispensable for students of navigation course. Especially in steering, different movement such as kick, turn, heel, will arise simultaneously for a short time in a transition stage until it goes into steady turning motion immediately after taking rudder. In order to realize more effective education about steering, we developed a simulation system as an educational teaching material, which enables display of many phenomena in accordance with turning motion. In this integrated steering simulation system (ISSS), output data obtained from a ship-handling simulator were processed and displayed on the animation, which is easy to understand visually. Five sub-windows are displayed on the main screen of the ISSS: hull movement and vector; locus of hull; position of pivoting point; heeling; time series data such as ship's speed, turn rate, heel angle, drift angle and transition of pivoting point. Concerning with the educational effect of this steering simulation system, the experiment was conducted and the effectiveness was verified by the test and the questionnaire. It can be said that the group, which received the lecture using the ISSS was able to understand the simultaneity more correctly about the phenomenon simultaneously generated in the initial stage of turning motion comparing with the group, which received the lecture in classroom without using this simulation system.
A ship-handling simulator has been used as a tool to simulate real ships for training purposes, but it is now expected that ship-handling simulators will be used as a teaching material to support lectures in classroom at maritime education and training institutions.
In a subject involving ship-handling theory, not only ship-handling skills but also a theoretical understanding of ship motions is indispensable. Experience gained through the use of a ship-handling simulator enables students to empirically understand ship motions. However, it is difficult to help students understand the dynamic mechanism behind the generation of ship motions.
To use a ship-handling simulator not only for training but also for education, it needs to be improved so that calculation outputs from the ship-handling simulator are processed into the visual]y understandable dynamics information shown additionally.
It is considered to be instrumental for providing students with deep and solid understanding of the theory of ship motions to combine experience gained through the use of a ship-handling simulator and visual-aid information that can display the dynamic mechanism of ship motions in a visually understandable form.
During steering operations, in particular, a variety of phenomena occur simultaneously in a brief time, including: drift, turning, speed reduction, displacement of pivoting point, kick, drift angle, heeling, etc. Lectures in classroom using a blackboard can only explain these individual phenomena, one by one, occurring simultaneously after the rudder is taken, separately, so it is not easy to have students correctly understand that these phenomena are occurring simultaneously.
From these points of view, the authors have developed an Integrated Steering Simulation System (ISSS) that is capable of processing a variety of dynamic data outputted from a ship-handling simulator into a visually understandable form of animation, displaying the processed information on a 50-inch display screen.
To validate the usefulness of this system for promoting students' achievements, an experimental study was conducted with the subjects of students in Kobe University of Mercantile Marine.
2. FUNCTION OF THE ISSS
2.1 System Configuration
Work Station 02 manufactured by Silicon Graphics was used for developing ISSS. C language was used for developing programs. Motif was used as a user interface library. OpenGL was used as the graphic library for displaying graphics. The ship-handling simulator of Kobe University of Mercantile Marine was also used as a simulator to be linked to the ISSS.
Fig. 1 System configuration of the ISSS
Fig. 1 shows the system configuration of the ISSS. This system is composed of the Management Section that receives data covering moment-to-moment ship's positions, course and speed, and transmits data received to each display, and the Displays Section displays an animation after processing of received data into graphic information.
2.2 Composition of Displayed Screen
Fig. 2 is a photo showing the 50-inch display unit of the ISSS, which is installed on the port side of the bridge mockup of the ship-handling simulator.
50-inch display unit of the ISSS installed m bridge mockup
Fig. 3 shows a screen displayed on the 50-inch display unit of the ISSS, which is linked with the ship-handling simulator.
At each sub-window of the screen, normal pressure acting on the rudder, force and moment acting on the centre of gravity of the hull, ship position and posture, ship's speed (speed component in the longitudinal direction: u, speed component in the transverse direction: v, composite velocity vector: Vs), turning angular velocity, drift angle, changes in position of pivoting point and heeling angle, etc. are displayed as both numerical information and animation.
Fig. 3 The 50-inch display unit of the ISSS
Viewing the screens of this newly developed system, students can learn correctly and effectively a variety of phenomena generated simultaneously in a brief time in association with steering attempts, while experiencing steering operations with the ship-handling simulator.
The contents of the individual sub-windows displayed on the screens of this ISSS are as follows: