Available online at www.sciencedirect.com Available online at www.sciencedirect.com
Procedia Engineering
ProcediaProcedia Engineering 00 (2011) Engineering 15 000–000 (2011) 3875 – 3880 www.elsevier.com/locate/procedia
Advanced in Control Engineering and Information Science
Study on Dynamic Simulation System for Vessel’s Collision Process and Its Application Shenhua Yang a, Guoquan Chena a* a
Jimei University, Xiamen and 361021, China
Abstract In order to reappear the process of vessels’ collision, the paper presented a project of dynamic simulation system for vessel’s collision process based on the technology of Ship Handling Simulator, and then made a discourse upon framework and key technologies of the system and workflow of dynamic simulation, and finally reappeared an accident of collision, which occurred in the north fairway of Changjiang Kou, using the developed system. The study on the system and its application may offer administrator of maritime safety a new approach for investigating and analyzing the accidents of vessel’s collision.
© 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [CEIS 2011] Open access under CC BY-NC-ND license.
Keywords: Ship Handling Simulator, accident of collision, dynamic simulation, electronic chart, three-dimensional vision;
1. Introduction According to statistics of IMO, in the shipwreck took place in the world, more than 30% of them are caused by collision[1]. Maritime collision, because of its high proportion, large losses, difficulties in the investigation and handling etc., was concerned by the judiciary, marine industry and maritime safety authorities. However, the analysis of collisions at sea is not only rigorous technical and legal issues, but also mixed with a lot of interpersonal and social problems. People have an instinctive sense of selfprotection, so to get a complete and accurate process after the accident from the parties is very difficult.The parties usually accidentally or intentionally exaggerated or disguise the process, their testimony is very arbitrary. Unlike the road accident scene which can be maintained, objective evidence of the accident is likely to disappear in subsequent operations. Sometimes for business reasons or the
* Corresponding author. Tel.: +86-592-7961518; fax: +86-592-6181415. E-mail address:
[email protected].
1877-7058 © 2011 Published by Elsevier Ltd. Open access under CC BY-NC-ND license. doi:10.1016/j.proeng.2011.08.725
23876
Shenhua Yang andetGuoquan ChenEngineering / Procedia Engineering 15 (2011) 3875 – 3880 Shenhua Yang al. / Procedia 00 (2011) 000–000
purpose of civil compensation, it is even deliberately concealed or modified (including logs and Marine reports) [2]. With the rapid development of science and technology, computer technology has penetrated into all areas of social life. Research on the virtual reality system combined with modern navigation has produced the ship handling simulator. Ship Handling Simulator is a multidisciplinary simulation system, fused of computer technology, computer graphics, computer vision and modern navigation etc[3-5]. Using computer systems to simulate the collision process of two vessels real timely and dynamically, and implementing ship operating measures each vessel adopted in the simulator, you can get position, course and the relative position of them and other data at every moment before the collision of two ships. This information has important reference value for the determining collision responsibility of two ships. Therefore, the Simulation environment（including the shoreline, water depth, aids to navigation, air flow, etc.）should be consistent with the environment when the accident occurred. The simulation ship mathematical model and the actual accident ship should be very similar in handling performance. Navigation & control programs of the simulation ship should be consistent with the actual navigation & control programs of the ship involved before the collision. People who implementing the simulation program should be a staff engaged in the maritime industry. In operation, we should also take full account of the impacts on manipulation results because of control officers’ psychology. Under these conditions, the results of simulation and related data are valid, credible, which can provide a scientific basis for Judiciary, Navigation and Marine Safety Authority to analyze accident and determine responsibility. 2. Construction of dynamic simulation system for ship collision 2.1. System structure Building Dynamic simulation system of ship collision based on handling simulator technology includes the following work: build electronic charts of simulation areas, take the litigant ship as a prototype, build ship motion mathematical model used to simulate the ship handling based on the involved ship; build analog control and process record software about navigation, and entering and leaving port, berthing and departing, develop peripheral interfaces and related support software of Ship handling, and research threedimensional scene of accident water area etc.. Therefore, the framework of system is shown in Fig. 1.
Fig.1. Framework of dynamic simulation system for vessel’s collision process
3877 3
ShenhuaShenhua Yang andYang Guoquan / Procedia Engineering 15 (2011) 3875 – 3880 et al. /Chen Procedia Engineering 00 (2011) 000–000
2.2. The key technologies 2.2.1. Making electronic chart of accident area Construct dynamic simulation system for vessel collision, firstly, According to the need of simulation we should choose a paper chart with latest version and put it into digital form, then produce an electronic chart of the accident area. The information such as navigation channel slot, depth, navigation aids, obstruction, shoreline etc. which have important meaning to analysis of the maritime, should be reflected accurately on the electronic chart. Putting the paper chart into digital form and displaying it on a computer screen needs to transform Mercator coordinates into computer screen coordinates and transform geographic coordinates into screen coordinates when working on the electronic chart. Overall, in the Electronic Chart Display algorithm, the main problem is types of coordinate transformation. Specific description as follows[6]: In the Mercator projection of navigation charts, q is called equivalent latitude, then: e
⎛ π ϕ ⎞ ⎛ 1 − e sin ϕ ⎞ 2 (1) ⎟⎟ q = ln tan ⎜ + ⎟ ⎜⎜ ⎝ 4 2 ⎠ ⎝ 1 + e sin ϕ ⎠ where e is Earth flat rate, ϕ is geographic latitude. So, using Newton iteration method, geographic latitude ϕ can be get through inversing equivalent latitude q. Namely: π ⎧ q ⎪⎪ϕ 0 = 2 arctan( e ) − 2 (2) ⎨ F (ϕ i ) ( i = 0 ,1, 2 , / ) ⎪ϕ i +1 = ϕ i − ⎪⎩ F ′(ϕ i ) e
2 Among them, F (ϕ ) = ln tan ⎛⎜ π + ϕ ⎞⎟ ⎛⎜ 1 − e sin ϕ ⎞⎟ − q , iterations until ϕ i +1 − ϕ i < ε . ⎜ ⎟ ⎝ 4 2 ⎠ ⎝ 1 + e sin ϕ ⎠ Take lower left corner of the electronic chart as the origin of coordinates O when the North up. OY axis is up. OX axis is right. Unit is mm. To establish logical display coordinate system. To set up a paper chart or a cutting rectangular area on a paper chart, its upper left corner geographic coordinates as point A(ϕ1 , λ1 ) ; the lower right corner as point B (ϕ 2 , λ 2 ) ; M (ϕ , λ ) is any point in the graph. When the figure display in the graphical display, points A, B and M correspond to logical display coordinates a ( X 1 , Y1 ) , b( X 2 , Y2 ) and m( X , Y ) . And suppose equal latitude of points A, B and M is q1, q2 and q3 respectively. Then:
λ2 − λ1 X 2 − X1 = X − X1 λ − λ1
q 2 − q1 Y2 − Y1 = q m − q1 Y − Y1
(3)
From the equation (3), (4), we get:
X=
λ=
λ2 X1 − λ1X 2 X 2 − X1 + ⋅λ λ2 − λ1 λ2 − λ1 λ1X 2 − λ2 X1 λ2 − λ1 X 2 − X1
+
X 2 − X1
⋅X
(5) (7)
q 2 Y1 − q1Y2 Y2 − Y1 ⋅ qm + q 2 − q1 q2 − q1 q Y − q2 Y1 q 2 − q1 qm = 1 2 + ⋅Y Y2 − Y1 Y2 − Y1
Y=
(4)
(6) (8)
If the logical coordinates Y of point M is known, from equation (8) first we can obtain the corresponding equivalent latitude q. Then we solve geographic latitude from equation (2) iteration.
43878
Shenhua Yang andetGuoquan ChenEngineering / Procedia Engineering 15 (2011) 3875 – 3880 Shenhua Yang al. / Procedia 00 (2011) 000–000
If the latitude ϕ of point M is known, then choose equation (1) to find the equivalent latitude q, and then from equation (6) we get the logical Y coordinate. 2.2.2. Build maneuvering motion mathematical model of the litigant ship Building maneuvering motion mathematical model of the litigant ship is the core of the collision accident simulation, which determines the validity and accuracy of simulation results. This article used such kind of modeling method, which based on mathematical model of fluid-mechanics combination, and combine with motion-responsive mathematical model in the low-speed, shallow water and other state. Meanwhile, it takes into full account of the mathematical treatment of the propeller power calculation of the four quadrants, which makes the calculation of the endpoint and a certain extension accurate and reliable. It used Holtrop resistance calculation method which makes the fat large vessels and bulbous resistance calculation more accurate. It completed the work of mathematical regression with a certain extension capability of Blue Wave-Oven Keller map[3][4].
Fig.2. Reference frame of ship’s movement
Coordinate system used in modeling is shown in Fig. 2, is the Geographical coordinate system fixed in the Earth, OXYZ is the moving coordinate system fixed in the ship.On this basis, establish ship maneuvering motion equations as (9). ⎧(m + λ11 )u&− (m + λ22 )vr − (mxg + λ26 )r 2 = X H + X P + X R + X W + X F + X C + X A + X L + X T + X S ⎪ (9) ⎨(m + λ22 )v&+ (m + λ11 )ur + (mxg + λ26 )r&= YH + YP + YR + YW + YF + YC + YA + YL + YT + YS ⎪( I Z + λ66 )r&+ (mxg + λ26 )(v&+ ur ) = N H + N P + N R + N W + N F + N C + N A + N L + N T + N S ⎩ Among them, m is the quality of the ship, I Z is rotational inertia of the hull itself around Z axis, λ11 , λ22 is the X-direction and Y-direction attached quality of the shiphull, λ66 , λ26 is the attached inertia and
static moment around the Z axis, x g is the X-axis coordinate of the center of gravity. u, v are components of the velocity vector in the X, Y axis. r is the rotary angular velocity of the ship. X is the longitudinal force acting on the hull. Y is the lateral force acting on the hull. N is the yaw torque acting on the hull. Subscripts H, P, R, W, F, C, A, L, T and S, indicate respectively the hull, propeller, rudder, wind, wave, current, anchor chain, back to the rope, tug and side wall effects. 2.2.3. Development of visual system
The large ship handling simulator with three-dimensional scene is the most advanced ship handling simulator, the most prominent advantage of which is intuitive. Not only can it reflect different effects of ship maneuvering caused by the day, night, and poor visibility, but also in the simulation experiments
3879 5
ShenhuaShenhua Yang andYang Guoquan / Procedia Engineering 15 (2011) 3875 – 3880 et al. /Chen Procedia Engineering 00 (2011) 000–000
demonstrate the ship blind and give the ship manipulator some environmental pressure. It is more realistic to simulate the accident area navigation environment and improves simulation accuracy. In three-dimensional scene modeling of the accident waters, MultiGen Creator is package software which is powerful and set a variety of functions in one. It has OpenFlight data format for real-time applications optimization, and has the functions of powerful polygon modeling, vector model, and large area terrain precision generation. It can not only perfectly generate single model such as the ship, buildings etc., but also in time use its intuitive visual interface for editing, adding and texture paste in the OpenFligh format FLT file. The finished model can create three-dimensional virtual scene of the maritime occurred by the combination of VEGA development tools and Visual C++ development platform threedimensional driven model[7]. 2.2.4. Dynamic Simulation System test for Ship Collision The test is to verify whether the simulation environment, simulation ship maneuvering characteristics and the actual environment of the accident water, handling characteristics of ships involved are similar. If they are, then the simulation results have reference value. Simulation must provide the true maneuvering performance of the prototype ship under given conditions, and accordingly test the maneuverability of the simulation ship. Usually, comparing of the prototype ship performance parameters and simulation ship, at least, we should compare the cycle performance with the braking performance when ship is in the ballast and under full load[8]. Upon examination, the similar of handling performance parameters between prototype ships and ship simulation must be consistent with A.751(18) Resolution "temporary ship maneuverability standards "adopted by IMO 1993. 3. Application examples At 00:11 on April 23, 2004, A and B collided in the Yangtze River Estuary North Channel Waterway near D22 lights floating. In order to further scientific synthetically reflect the collision of two ships, used SMU-VI new ship handling simulator which accessed to Ministry of Science and Technology Progress Award, A&B ship maneuvering model and corresponding three-dimensional scene, and combined with the prevailing wind, flow, we developed a dynamic simulation system for ship collision and carried out a large number of simulation tests on the collision process. Ship A
Ship B Ship B
Ship B Ship A
Fig.3. Track chart of simulation test on the recorded data of rudder of vessel ‘A’
Fig.4. Recurrence of collision process between vessel ‘A’ and ‘B’ by the way of two-dimension
Ship A
Fig.5. Recurrence of collision process between vessel ‘A’ and ‘B’ by the way of three-dimension
1) The track test corresponding to A ship rudder angle According to "A" ship's rudder angle, vessel position records and other data a few hours before the collision provided by maritime authorities, carried out a large number of simulation experiments critically according to the time series and recorded simulation test data and results, then to study the rudder effect situation of ship "A" through concluding, arrangement, process playback and analysis. The results show
63880
Shenhua Yang andetGuoquan ChenEngineering / Procedia Engineering 15 (2011) 3875 – 3880 Shenhua Yang al. / Procedia 00 (2011) 000–000
that, manipulation under the rudder angle record data of ship "A", at 00:11 it be off and out of the ship channel, and will not encounter B in the vicinity of D22 lights floating . As shown in Fig. 3. 2) Collision simulation According to the ship track records of the Yangtze Estuary VTS center, using simulation platform can reproduce the collision of the two ships through three-dimensional or two-dimensional, which is conducive to analyze objectively the causes of the collision. As shown in Fig. 4-5. Through a large number of simulation experiments for the collision process and analyzing the rudder usage, speed and course of ship A&B for every simulation experiment, analyze possible causes of the collision. (1)"A" rudder equipment became abnormal within a short time under sailing conditions at the time ; (2)"A" rudder equipment exists efficiency differences between left and right rudder steering device actually; (3)"A" did not properly control the its position when it sailed in the channel for some time ; (4)Two ships at that time considered the impact of air flow insufficiently. 4. Conclusion Ensuring the objectivity and scientific of maritime survey and analysis is one of the most important parts to maritime security and is the important aspect of safeguarding the benefits of all parties of shipping. With the gradual installment of VDR, the accuracy, authenticity and continuity of the recorded data of shipping dynamic and operating information got by Maritime investigators can not be got by traditional Maritime survey. It will increase the reliability and authenticity through using ships handling simulator technology to make collision dynamic simulation. Besides, Experts and scholars home and abroad made extensive and in-depth research in the ship automatic avoidance collision recent years, if we could insert the intelligent shipping automatic avoidance collision system into the shipping collision dynamic simulation system, according to the sea conditions and meeting trend, the system can supply the correct and reasonable plans of handling and anti-collision to involved ships, and we can easily and clearly judge the misfeasance and responsibility of involved ships by comparing the rudder record. This will be the direction for our future study. Acknowledgements This work is partially supported by Natural Science Foundation of Fujian Province, 2009J05148, and the Foundation for Young Professors of Jimei University. References [1]Li Pu. Research and prevention on current situation of ship collision. Maritime Technology, 1996, 3: 2-4. [2]Liu Jingxian. VDR and maritime investigation.China Water Transport, 2003, 2: 12-13. [3]Shi Chaojian, Cai Cunqiang. Development of SMU-IV composite shiphandling simulator. Journal of Shanghai Maritime University, 1998, 19(4): 32-37. [4]Le Meilong. The prediction of Ship manoeuvring and simulation of incoming control motion. Shanghai: Shanghai Jiao Tong University Press, 2004. [5]Yang Shenhua, Xiao Yingjie. Application of Ship Manoeuvring Simulator in the Selection of Shanghai LNG Reception Terminal Project. Maritime Technology, 2004, supplementary issue: 26-30. [6]Zhang Junying. Mathematic and algorithm basic of electronic chart. Dalian: Dalian Maritime University Press, 2001. [7]Guan Keping, Wang Shengzheng, Chen Jinbiao. A Kind of New Method to Make Terrain Data File in the Navigation Simulator. Journal of Shanghai Maritime University, 2003(3): 213-216. [8]Jia Xinle, Yang Yansheng. Ship motion mathematical model-Modeling and identification modeling mechanism. Dalian: Dalian Maritime University Press, 1998.
