Lab, v. Scheepsbouwkuncie

Technische Hogesckool

Deft

Paper n. 5

"MASTERPILOT SYSTEM MANOEUVRE CONTROL"

E. Brizzolara - SCHOTTEL ITALIANA

NAV '88 - WEMT '88 SYMPOSIUM

Trieste, Italy

12 - 13 - 14 October 1988

I

Abstract:

The inst&llation of many azimuthal thruster on thesame vessel permit to reach unexpected manoeuvra-

bility. To simplify the shipmasters control of

many units simultaneously, Schottel developed itsown computerized control, called MASTERPILOT.

This device is able to control each unit in thrustand direction in order to obtain the requested

ship movement in parallel motion with or withoutsuperimposed turning angle.

The hardware is a Schottel standard product, mean-while the software is developed for each applica-tion based on Schottel large experience.

The MASTERPILOT units are installed in a large

number of different type of vessels, like ferries,

tractor tugs, special ships, firefighting boats,defence vehicles, etc.. arid can control any numberof thruster.

5.1

The number of crafts and ships that are equipped with azimutal thruster

is growing continuously. The azimuthal thrusters or S.R.P. (Schottel

Rudder Propellers) are rarely installed as a single unit.

The biggest part of applications is related to two or more units on the

same ship and commonly the units are be of different powers or, better,

of different thrust.

In these applications the rudder proppellers can be controlled with

different systems:

- a - one by one with single and separate follow-up control;

- b - with automatic computer control for D.P. operations;

- c - with one hand lever computerized control.

The system - a - still in use for ships equipped with 2 or 3 SRP is

shown in figure 1 and consist of one small pre-selecting wheel for each

azimutal thruster.The consolle shown in figure 1 is the pilot-house consolle of a tanker

equipped with 2 SRP at the stern.

For special applications like D.P. in the offshore vessels the number

of SRP installed on board can be 4 or more reaching also 8 or 10

units.All the SRP are controlled in thrust and in azimuth automatically by

the D.P. computer (system - b -). But many applications require a

prompt, direct shipmaster control and, of course, it is not simple for

him to steer all the power units simultaneously, during quick and

precise manoeuvres.

This is the reason why Schottel developed the MASTERPILOT System for

their rudder propellers and for their azimuthal jets.

The function, advantages and experiences with this usefull steering

device can be described as follows.

A ship with two or more Rudderpropellers or other manoeuvring aids can

execute almost all conceivable manoeuvres and motions. Therefore, not

only it can sail straight ahead, astern or in random curves, but it can

also, as shown on the figures 2 and 3, move transversally in random

directions in addition to superimposed rotations and also turning on

the spot.

In developing the input device and the software, Schottel have taken

other handling and application scope approaches in comparison with

competitors.The system configuration of the tractor tug was chosen as the first

program.And this was for a good reason, because the customer had seen repeated

demonstration of perfect tug manoeuvring in the port of Hamburg.

The fact that a lot of experience and practise is required for this

purpose, however, was mostly overlooked. Translating this experience

5.2

into a program and developing a simple input device for the purpose wasthe first objective.

In the meanwhile this software has been supplemented by many others and

so almost any propulsion configuration is programmed. (Figure 4)

Now a few basic details of the Masterpilot:

The Schottel Masterpilot control is a microcomputer control for ships

(Figure 5).

A clearly arranged input unit permits the shipmaster to execute all

conceivable manoeuvres extremely rapidly without having to waste

thoughts of engine speeds, propeller pitches or directions of thrust.

The shipmaster can thus concentrate himself entirely on the ship's work

and mission, while the microcomputer relieves him of the task of set-

ting control elements.

The MASTERPILOT control permits ship's motions with a degree of

precision wich would demand a considerable amount of experience of the

part of the shipmaster if the thrusters were to be controlled manually.

The input unit of the Masterpilot control is matched in the best

possible way to the ship's possibilities of movement. In order to

undestand it, it is first of all necessary to remember, that the motionof a ship can basically be split up into two parts: a longitudinal

motion and a rotation.It is thus logical that the input unit is designed so that the direc-

tion and the intensity of both motions are entered separately and can

be superimposed on each other (Figures 6 and 7).

The central lever specifies the direction and intensity of the required

longitudinal motion while the outer handwheel specifies those of the

required rotation.The complete task of evaluation and control is performed by the micro-

processor (Figure 8). With the aid of its program the computer controls

the thrust angle, clutches and the speed of all thrusters (or pitch of

CCP)The program integrates optimized Rudderpropeller settings and

experience with the respective system configuration, thus dispensing

with problems in direction of rotation inputs for direction reversals

or for tranversing with superimposed rotations. Even if a few system

components should fail, the simple input setting will not change and,

with the aid of an emergency program, the computer will determine and

realize the ship's motions which are still possible.

Manual intervention in the steering program is also possible.

For instance, a system can be deactivated to save fuel, or it is

possible to switch between high speed (sensitive steering) and

manoeuvring speed.

5.3

Just like the COPILOT system the Masterpilot input lever can also be

equipped with a slaving control for simple switchover of the control

position during operation.

For an automatic heading an Autopilot can be connected to the

Masterpilot system.

In this case the Autopilot replaces the handwheel of the Masterpilot

input unit.

Software errors such as program interrupts or hardware faults in the

computer system results an immediate switching to an emergency system.

All occuring faults and errors are additionally signalled visually and

acoustically.

5.4

01

01

the Copilot corisolle in a tanker

equipped with 2 SRP at the stern

UNBEGRENZTE MANVRIER-MGLICHKEITENDURCH

urirestri cted manoeuvrabi 1 ity

through a Schottel tractor tug

Figure 2

5.6

UNBEGRENZTE MANtVRI ER-MOGLICHKEITENDURCH

unrestri cted manoeuvrabi ii ty

through a Schottel stern tug

Figure 3

5.7

SUOfl6!.JUOuo!.SlfldO.Ad aqssod

'

111MICRO COMPUTER

T J

the principle of a f1asterpilot

system for a ship with two Rudder-

propellers in the stern and two

lateral thrusters in the bow

Figure 5

5.9

REMOTE REMOTE REMOTE REMOTECONTROL CONTROL CONTROL CONTROL

DEVICE DEVICE DEVICE DEVICE

the input device of the Schottel

Masterpilot System (900 transverse

and superimposing rotation)

Figure 7

5.11

m -5 (D co