Device for controlling the direction of movement and thrust force of a watercraft

A watercraft includes two steerable propellers driven by motors, the angular positions of and the thrusts produced by the steerable propellers being controlled by a control system. The control system includes an input device having a frame, a head and a handwheel supported on the frame for independent pivotal movement about a common first axis, and a lever supported on the head for pivotal movement about a second axis normal to the first axis. The head, handwheel and lever are each operatively coupled to a respective input element by a respective gear arrangement. A microcomputer responsive to the input elements is connected through several control devices to the motor and the steerable propellers for effecting the requisite control thereof.

FIELD OF THE INVENTION 
This invention relates to a device for controlling a watercraft and, more 
particularly, to a device for controlling the direction of movement and 
the force in such direction of a watercraft having at least two thrust 
generating devices, at least one motor for driving the thrust generating 
devices, and an input device which can control rotation of the watercraft, 
linear movement of the watercraft, and the thrust forces which produce 
these movements. 
BACKGROUND OF THE INVENTION 
In the sense of the invention, the term thrust generating devices includes 
all drive members suitable for the mechanical drive of a watercraft, for 
example a steerable propeller, a jet drive, a cycloidal propeller and 
others. 
Devices of the foregoing type are already known, for example a control 
device with a single lever which is supported in two crosswise arranged 
members which are rotatable about perpendicularly arranged axes, which 
members operate electrical circuits which control a pair of steerable 
propellers. If the lever is deflected in any direction which does not lie 
on an axis of rotation of the members all senders are operated. (See U.S. 
Pat. No. 3,976,023). 
Also, a device of the above-mentioned type is known with which a watercraft 
can be controlled for rotational and linear movement by means of a lever. 
The control impulses are forwarded from the lever through sending devices 
to the thrust generating devices, which serve several functions. They are 
effective both for linear and also rotational movement of the watercraft. 
(See German Offenlegungsschrift No. 30 13 654, which corresponds to U.S. 
Pat. No. 4,418,633). 
When two or more functions are combined with a common lever, and a control 
element thus serves several functions, it is hardly possible to control a 
change in the direction of travel without necessarily changing the 
effective thrust strength. If the helmsman wants to carry out only a 
single control function, he must have great sensitivity and experience in 
order to do so in a precise manner. In the conventional devices, the 
effective thrust of the steerable propellers or other thrust generating 
devices is in some circumstances, for example during forward travel, 
stronger than that with the same control lever inclination in other 
circumstances, such as transverse travel. The reason is that, in any 
desired direction of movement other than straight forward or backward, the 
thrusts of the steerable propellers are always directed at least partially 
against one another, namely, at different angles. 
It is a purpose of the invention to avoid the described problems, or in 
other words to provide a device for driving and controlling watercraft and 
the like with which all conceivable maneuvers and movements can be carried 
out, for example travel straight ahead and back, rotation along any 
desired curve and in any desired direction or in one spot, and also 
transverse movement, if desired with superposed rotation, and in which the 
required thrust strengths can in each case always be predicted for the 
helmsman without unintentional changes occurring during adjusting of the 
presetting lever. 
A further very important purpose is to prevent control settings from being 
inadvertently selected which might endanger the watercraft. 
A further purpose of the invention is to make it clear positionally and 
visibly at the input device, namely, on the lever, handwheel or the like, 
which direction and thrust strength have been selected for the watercraft. 
Only through this does an indication for thrust reversal for stopping the 
vehicle by means of the input device become possible, or at least easier. 
SUMMARY OF THE INVENTION 
The purposes of the invention are met by providing a device which includes 
a first input element for defining the force of a linear movement of the 
watercraft, a second input element for defining the direction of such 
linear movement, and a respective control member operatively coupled to 
each such input element. 
Particularly advantageous is a development of the invention which includes 
a third input element and associated control member for defining the 
direction and magnitude of a rotational movement of the watercraft. 
Through these characteristics, all movements of the watercraft are cleanly 
separated from one another at the input device. 
A further very important development of the invention involves the 
provision of a microcomputer responsive to the input elements. Due to the 
fact that, for each function of movement, a separate input element is 
provided which is not influenced by the other input elements, the 
microcomputer can control the thrust for linear movement, the direction of 
linear movement, the direction of rotation, and the magnitude of rotation. 
Furthermore, additional maneuvering devices can be provided, for example 
lateral thrust rudders. If jet drives are used, then not only their 
rotation, but also their valves or the like can be controlled. In the case 
of cycloidal propellers, the wings can be adjusted. Moreover, the 
microcomputer can regulate the drive motor or any clutches and, if 
desired, adjust the propeller blade pitch. 
Through a further feature which includes a locking arrangement, a very 
dangerous control error can be avoided, namely, that during full speed 
forward travel a lateral thrust is inadvertently selected. 
A simple and central combination of the final control elements in one unit 
results from the control member for the second input element being a head 
supported for pivotal movement about a first axis and operating the second 
input element through a gear arrangement, the control member for the first 
input element being a lever pivotally supported on the head for movement 
about a second axis normal to the first axis and operatively connected to 
the first input element by a gear and rack arrangement, and including a 
handwheel supported for rotation about a third axis and operatively 
connected by a gear arrangement to a third input element. This arrangement 
is further improved if the first and third axes are coincident. These 
characteristics are further improved, in order to avoid the 
above-mentioned inadvertent and dangerous control situation, by providing 
a frame having slots which receive the lever when the thrust producing 
devices are each producing a force substantially in a common direction 
which is parallel to the center plane of the watercraft. In order for the 
thrust in forward and backward directions to be carried out with a greater 
force than during traversing, and so that the helmsman gets a feeling for 
these relationships, the invention can be developed so that the maximum 
possible movement of the lever from its initial position is larger when 
the watercraft is being moved in purely forward and reverse directions 
than in any other direction. 
The invention makes it possible for the helmsman to quickly carry out all 
conceivable maneuvers without having to worry about motor speed, propeller 
pitch or thrust direction. The watercraft movements can thus be carried 
out with a precision which is not possible with a manual control, even 
when operated by trained personnel.

DETAILED DESCRIPTION 
FIG. 1 is a block diagram of a preferred arrangement of a system for 
driving and controlling a watercraft 1, the center of gravity of which is 
identified by reference numeral 2. On opposite sides of the vertical 
center plane 3 of the watercraft are provided two steerable propellers 4 
and 5 which are conventional and therefore not described in detail, and 
which are supported for pivotal movement in a conventional manner about 
respective vertical swivel axes 6 and 7 and can be pivoted about such axes 
by servomotors 8 and 9. Two motors 10 and 11 are provided to effect 
propeller rotation. Between the motors 10 and 11 and the steerable 
propellers 4 and 5 are provided respective clutches 25a and 25b. 
To control the drive system, an input device 50 is provided and includes 
three input elements 12, 13 and 14 which, in the preferred embodiment, are 
potentiometers controlled by respective manually engageable control 
members 15, 16 and 17. 
The first potentiometer 12 is operated by a lever 15 and, through a 
microcomputer 18, changes the thrust strength by adjusting the angular 
position of the steerable propellers 4 and 5, by changing the speeds of 
the motors 10 and 11, and/or by changing the pitch of the propeller 
blades, as shown in FIGS. 7a to 9a. 
The second potentiometer 13 is operated by a head 16 and, through the 
microcomputer 18, controls rotation-free transverse movement of the 
watercraft by pivoting the steerable propellers or by changing the speed 
or pitch of the propeller blades, as shown in FIGS. 12a through 13c. 
The third potentiometer 14 is operated by a handwheel 17 and, through the 
microcomputer 18, controls the rotation of the watercraft according to the 
desired direction and degree of rotation, namely, according to a curve 
radius determined for the rotation. If desired, rotation in one spot can 
be effected. Examples of rotational movement are shown in FIGS. 10a, 14a 
and 16a. 
The three potentiometers 12, 13 and 14 act onto the microcomputer 18. The 
outputs of the microcomputer act onto course-dependent control devices 19 
to 24. These control devices are conventional. They are typically 
amplifiers with electronic compensating circuits which adjust output 
signals from the microcomputer 18 to a form compatible with the control 
inputs of the devices which are to be controlled, such as servomotors, 
throttle valves, clutches and so forth. The microcomputer 18 is programmed 
so that it converts the information from the potentiometers 12-14 into the 
desired direction of movement (by positioning the steerable propellers) 
and the desired thrust (by controlling motor speed and/or propeller blade 
pitch). It calculates the necessary speeds and rudder positions. By means 
of test calculations, the input and output signals and the program and 
operating sequence are determined. It is designed in each case to 
correspond to the particular arrangement of the propellers in the 
watercraft. For example depending on whether a front drive, a rear drive, 
or both are provided. If jet drives are used instead of steerable 
propellers, then the microcomputer 18 controls either the angular 
positions or, if flaps are present, the flap positions. In the case of 
cycloidal propellers, control of the wing position can be incorporated 
into the program. In addition, the program can also control lateral thrust 
rudders or other maneuvering devices. 
For controlling the watercraft, its movement is inventively divided into 
basically two components, namely, into a linear or rotation-free movement 
in any desired direction and into a rotational movement. Both components 
can be calculated separately and can then be superposed to achieve the 
direction and speed of movement called for by the input device 50. 
The analog signals of the potentiometers 12, 13, 14 are converted into 
digital signals in the microcomputer 18 (FIGS. 17A and 17B) by a 
commercially available, adjusted analog-to-digital converter card 51. From 
given values of these digital signals, the steerable propeller angles 
which correspond with these given values and the thrust values, such as 
motor speed, propeller blade pitch and the like, are calculated on a 
calculating card 52, namely a microprocessor (for example a module 
available from the firm Motorola). These calculations are dependent on the 
arrangement of the steerable propellers in the ship, and in particular on 
whether for example two steerable propellers are arranged in the front 
region or the rear region of the ship. Also, other propeller arrangements 
can be considered. Characteristics of these arrangements are stored in 
so-called EPROM's. (EPROM's are commercially available parts, which for 
example are manufactured by the firm Motorola.) 
The thus-calculated values are then converted by means of a 
digital-to-analog converter card 53 into analog signals and are fed to the 
corresponding electronic cards in a basic apparatus (FIG. 17B) as control 
signals. This basic apparatus contains evaluating logic circuits 55 and 
55', control cards 56 and 56' for speed adjustment, switching or 
proportional amplifiers 57 and 57' for 360.degree. control of the 
steerable propellers and/or for adjusting the propellers, coupling cards 
58 and 58' for the coupling and brake circuit, and a bus plate. 
In addition, the calculator can give signals for the coupling and 
uncoupling of the steerable propellers, which are forwarded through an 
opto coupling card 59 to the coupling cards 58 and 58' in the basic 
apparatus of the microcomputer. (An opto coupling card is an optically 
coupled isolating circuit located between the computer output and a 
further circuit, and is commercially available.) 
The system can be provided with a switch 61, through which the lateral 
center of gravity 2 corresponding with the condition of the ship, namely 
whether empty, half-loaded or fully loaded, can be considered. 
Literature is available on which the man skilled in the art can rely for 
implementing details of the inventive development and the described 
connections, for example U.S. Pat. No. 4,258,425 or publications of the 
firm Motorola or the firm Siemens. 
FIGS. 2 to 4 illustrate the input device 50, in which the potentiometers 
12, 13 and 14 and the control members 15, 16 and 17 are combined. The head 
16 is supported for rotation about a vertical axis 28 by a bearing 27 
which is fixedly connected to a frame 26. The lever 15 is adapted to 
facilitate rotation of the head 16. A gear 29 is secured to the lower end 
of the head 16 and mates with a countergear 30 secured on the drive shaft 
of the second potentiometer 13. 
The head 16 has a central vertical slot and a gear 31 is supported in the 
slot for rotation about an axle 32 which extends at a right angle to and 
intersects the axis 28. The lever 15 is secured on the gear 31. The gear 
31 mates with an intermediate gear 33 (FIG. 3) which is fixedly connected 
to a coaxial intermediate gear 34 adjacent to it. The gear 34 mates with a 
rack 35 which is supported for vertical movement along the first axis 28. 
The rack 35 mates with a pinion 36 which is secured on the drive shaft of 
the first potentiometer 12. 
The handwheel 17 is supported on the frame 26 for rotation about the first 
axis 28, and has a gear 37 thereon. The gear 37 mates with a countergear 
38 which is secured on the drive shaft of the third potentiometer 14. 
The bearing 27 has two slots 39 and 40 in its upper edge which lie 
diametrically opposite one another and along a line parallel to the center 
plane 3 of the watercraft. The lever 15 can move into the slots 39 and 40 
in its two extreme positions. Important positions of the control elements 
15, 16 and 17 can be defined by spring biased locking balls which engage 
detents, as at 41 and 42. The top surface of the bearing 27 serves as a 
sliding surface 49 for the lever 15, and is interrupted by the slots 39 
and 40. Through this, the angle .alpha. of the lever 15 in the pure 
forward and backward directions is larger than in all other directions. 
The consequence is that, for pure forward or backward travel, a greater 
thrust force is applied than in all other directions, and the helmsman 
feels this. A scale 43 is provided on the surface 49 of the bearing 27 in 
order to designate various positions of the head 16. Further, a double 
arrow 44 is provided on the frame 26 and a pointer 17a is provided on the 
handwheel 17 in order to identify the angle of rotation of .+-.90.degree. 
of the handwheel 17. 
FIGS. 5 and 6 show a modified version of the input device according to FIG. 
2, which modification concerns the slots for receiving the lever 15. In 
other respects, both input devices are identical. While in the embodiment 
of FIG. 2 the lever 15 engages the slots 39 and 40 only in its extreme 
positions, thus preventing rotation of the head 16, in the embodiment 
according to FIGS. 5 and 6 the corresponding slots 45 and 46 have 
respective shoulders 47 and 48 on each side thereof which extend radially 
inwardly above the head. Through this, fixation of the lever 15 relative 
to the head 16 first occurs at an angle .beta. of the lever 15 which is 
much smaller than the angle .alpha.. 
FIGS. 7a through 16c illustrate the relationship of the input device 50 to 
the thrust generating devices, namely, the steerable propellers 4 and 5 
(FIG. 7a). In FIG. 8a, as an example, the arrows indicate the direction of 
the propeller thrusts and the parallel lines indicate the water flowing 
away from the propellers, the length of the parallel lines indicating the 
thrust force. 
The zero or initial position of the controls is illustrated in FIGS. 7a and 
7b. The lever 15 is positioned vertically along the axis 28, and head 16 
and handwheel 17 are aligned for travel in a direction parallel to the 
center plane 3. The thrust directions of the propellers 4 and 5 are 
oriented in opposite directions and transversely to the center plane 3 of 
the watercraft 1. The clutches 25a and 25b (FIG. 1) are switched off and 
the watercraft does not travel. If the lever 15, while maintaining the 
described initial position of the input devices 16 and 17, is swung 
forwardly as shown in FIG. 8b, then the propellers 4 and 5 are started and 
pivoted a certain amount in opposite directions (FIG. 8a), so that a 
resulting forward thrust (FIG. 8c) is produced. The watercraft then starts 
to travel forwardly. When the lever 15 has covered the full angle .alpha., 
the propellers are positioned parallel with respect to the center plane 3, 
as shown in FIGS. 9a, 9b and 9c, and the watercraft travels forward at 
full speed. In this position, the lever 15 is in the slot 40 (FIG. 2) and 
the head 16 is thus fixed against rotation. It is therefore impossible to 
move the head 16 and initiate a traversing movement, which would be very 
dangerous in this condition of movement and speed. 
If the watercraft is then to be stopped, the lever 15 is swung back to its 
initial position. It is also possible to momentarily swing the lever 
beyond such position. From this results a thrust reversal which causes the 
watercraft to immediately cease movement in the forward direction of 
travel. This is true for every rotation-free movement of the watercraft. 
Backward travel is controlled in a similar manner by moving lever 15 
rearwardly. 
If the lever 15 is moved from its initial position but the head 16 is not 
rotated from its initial position, and if the handwheel 17 is then 
operated, then a rotation is superposed to the watercraft during forward 
or backward travel, causing it to turn. The microcomputer 18 decides 
whether the superposition must occur through a change in thrust force 
and/or a change in the angular position of the thrust generating devices. 
For approximately oppositely directed thrusts such as those in FIG. 8a, 
superposition is done through a change of thrust force, whereas for 
parallel thrusts such as those in FIG. 9a, a change in the angular 
position of the thrust generating devices is used. 
If the handwheel 17 is maintained in its initial or zero position and the 
head 16 is rotated, together with the lever 15, about the axis 28, then 
the thrust generating devices are controlled, by changing angular position 
and/or thrust force, so that a lateral thrust results in the direction in 
which the lever 15 points and which can be read on the scale 43, and with 
a thrust strength which depends on the inclination of the lever 15. See, 
for example, FIGS. 12a through 13c. The thrust angles and thrust strengths 
which are required for such movements depend on the arrangement of the 
thrust generating devices with respect to the center of gravity of the 
watercraft and on the dynamic behavior of the watercraft, all of which 
must be considered when preparing the program for the microcomputer. 
In order for the resulting thrust to always correspond with the position of 
the head 16, suitable thrust angles and thrust strengths are preset in the 
microcomputer 18. See, for example, the length of the parallel lines which 
indicate the thrusts behind the respective propellers in FIG. 13a. 
If, in addition to the control members 15 and 16, the handwheel 17 is also 
operated, then a rotation of the watercraft is superposed on the 
traversing movement, examples of which are shown in FIGS. 14a through 16c. 
If the lever 15 is in its initial position and the handwheel 17 is rotated, 
then the watercraft rotates in one spot. 
The entire arrangement for controlling a watercraft can also be such that 
the control system according to the invention has associated with it, for 
each thrust generating device, a control device such as a control wheel or 
gas lever which is not connected to the microcomputer 18, but is connected 
directly to the thrust generating device in the usual manner. It or the 
inventive device can be selectively switched on when this is desirous for 
any reason. 
Although particular preferred embodiments of the invention have been 
disclosed in detail for illustrative purposes, it will be recognized that 
variations or modifications of the disclosed apparatus, including the 
rearrangement of parts, lie within the scope of the present invention.