A STUDY OF SHIP HANDLING SUPPORT SYSTEM
Masatoshi Endo (Ishikawajima-Harima Heavy Industries Co., Ltd., Japan)
Abstract: In this study, it decided to aim at building of the human centered ship handling system by developing the ship handling support system which exposed a focus to the human characteristics of the ship operator. A ship handling in restricted water area and collision avoidance were made the target of the study as a fundamental maneuvering situation. First, as for the ship handling in restricted water area, the purpose of the study was to support to improve the result of maneuvering ship by the ship operator. A ship operator has the adaptive control characteristic which varies an own control characteristic in the change in the ship's length of the target ship. We utilize the adaptive control characteristic of the ship operator, and devised the support display which improved a ship operator characteristic by indicating a controlled variable in this study. An experiment by the ship handling simulator was done by using the devised support display. Devised controlled variable display is about the heading deviation angle and the turn rate. As for the display of the controlled variable, it was decided intuitively that a ship operator could grasp condition for maneuvering a ship. As for the display of the turn rate, it became clear that a ship operator characteristic could be improved remarkably in case of a large ship as that result. Next, we aimed to support ship operator to maneuver in collision avoidance safely and securely even if under the condition of high load for ship operator. As for the maneuvering in collision avoidance, original information throughput becomes a limit when a ship operator is set up in a state of high load. It paid attention to the information analysis, decision making process that a collision avoidance plan was planned in this research. The factor that the throughput of the ship operator becomes a limit in this process is the un-sureness of other ship movements. Therefore, we planed that a ship operator was supported by making other ship movements decision in this research. We devised the destination display and way point display of the other ship as an display of information to make an other ship movement decision, and carried out the ship handling simulator experiment Proper DCPA was obtained by the way point display with the decrease in analysis time of the ship operator as this result. As for the controlled variable display in the maneuvering in restricted water area and the way point display of the other ship in the maneuvering in collision avoidance, it became clear that a maneuvering support could be performed based on the ship operator character from the above.
Recently, an environment to surround a ship operator has been changing, and also the responsibility which a ship operator realizes for the safety service of the ship has been increasing. Specially, influences due to the sea disaster accident have been increasing caused by the enlargement of the hull.
The intervention of the human error is pointed out, and it is long in most of the causes of the sea disaster accident. A human error occurrence cause can be thought to have the room that a ship handling system can improve, though various things can be thought about it.
It has been proceeding with the development of a new ship handling system like LBS and the voyage information display device where it is represented by ECDIS, AIS, and so on as well on one hand. As for these machine kinds, it is working for the fulfillment on the function side. But, the function that it is equipped isn't made for the ship operator in detail the analysis about whether to be useful. In other words, it cannot but be said that it isn't being done based on the ship operator characteristic about the development of these machine kinds.
It can consider that improvement in a result of a maneuvering becomes possible with making a human error occurrence factor diminish by supporting in consideration of the human characteristics of the ship operator in this.
A maneuvering in restricted water area and a maneuvering in collision avoidance were featured in this research as a fundamental maneuvering situation, and a ship handling support method based on the ship operator characteristic was decided to be explained to each.
2. SUPPORTING SHIP OPERATOR IN THE MANEUVERING IN RESTRICTED WATER AREA
2.1 Characteristic improvement by the controlled variable display
A ship operator maneuvers with confirming three controlled variables of the lateral deviation, the heading deviation angle and the turn rate. Then, a ship operator increases the control coefficients concerned with each controlled variable when the confirmation of the turn rate can't be done.
In other words, the matter that ship operator's own control characteristic is made to change and made to adapt itself is being cleared. Such a characteristic is used, and the adaptive control characteristic of the ship operator is enhanced more by indicating a controlled variable effectively, and it is considered that it can get a good result of a maneuvering.
The display that a ship operator could grasp a turn rate and a lateral deviation easily was devised by this research. And, a heading used gyro repeater in this experiment, and decided to be grasped. A lateral deviation display screen is shown in Fig. 1.
Fig. 1 Lateral Deviation Display
As for the central perpendicular of the screen, the inside of the figure shows a planned course line. When a current position locates in the left, the symbol which shows an ownship is painted over with red and indicated. When a current position locates in the right, the symbol which shows an ownship is painted over with green and indicated. At this time, it is not a ship form, but it is shown by the circle the symbol which shows an ownship not to give a ship operator a prediction.
A turn rate display screen is shown in Fig. 2. The volume of the turn rate is shown with a fan type in these figures. Then, a fan type and the frame of the ship form are shown at the time of the left turn by red, and it is shown at the time of the right turn by green.
Fig.2 Turn Rate Display(in the Left)
Furthermore, a ship form is painted over with the development of the turn rate, by orange, decline, ashes white at the time of the left-right turn. It is painted over and shown with at the time of the left turn, by red, at the time of the right turn, green at the time of the fixed size without turn rate.
2.2 Controlled variable display experiment
A ship handling simulator experiment was carried out by using the display devised with a preceding paragraph. Examinees are skillful mates.
Moreover, this experiment made the condition which no display about the controlled variable was in a basis, and it was indicated lateral deviation, heading and turn rate, respectively, individual. Then, it led a ship operator control coefficients, and a difference in these display was explained.
The kind of the ownship made as a small size ship, the small size steel ship of a ship's length 100m, as a large ship, the container ship of a ship's length 280m the target here.
2.2.1 Control coefficients comparison
The control coefficients derived in each display experiments is shown in Fig. 3. The following became clear from the figure.
a. ship's length 100m
Not only control coefficients corresponding to the controlled variable made a display target in case as each display except for "NO. Support" but also the control coefficients which coped with other controlled variables increase.
b. ship's length 280m
In case of Turn Rate indication, Kx, Kp and Kd increase more remarkably than other cases in case as other display.
Fig.3 Control Coefficients derived in each display