FR3016154A1 - DEVICE FOR COMPENSATING THE ROLL OF A VESSEL, VESSEL COMPRISING SUCH A DEVICE AND ASSOCIATED METHOD - Google Patents

Abstract

Roller compensation device for a ship intended to be on board a ship (2) extending along a longitudinal axis (R) and comprising at least two propulsion units (4, 6) adapted to generate a first , respectively a second thrust (P1, P2) substantially parallel to the longitudinal axis (R) and substantially equal to one another, the compensation device (8) being configured to compensate for the inclination (r) of the ship around said longitudinal axis (R). The compensation device comprises a processing device (32) configured to determine the value of two compensation setpoints respectively to be applied by the propulsion units (4, 6) as a function of the inclination information of the vessel about said axis. longitudinal (R), the compensation instructions being both respectively representative of a thrust differential to be applied by one of the propulsion units (4, 6), the difference between the two thrust differentials being non-zero. Ship and associated compensation method.

Description

FIELD OF THE INVENTION The present invention relates to a device for compensating the roll of a ship. More specifically, the present invention relates to a roll compensation device for a ship intended to be on board a vessel extending along a longitudinal axis and comprising at least two propulsion units adapted to generate a first, respectively a second thrusts substantially parallel to the longitudinal axis and substantially equal to one another, the compensation device being configured to compensate for the inclination of the ship about said longitudinal axis. The field of the invention relates to roll compensation devices in the maritime field. In a known manner, the ships at sea undergo the effects of waves, which are reflected in particular by rolling movements. Swell induced roll can cause problems on board the ship. For example, the roll is likely to pick up items of cargo, or to damage certain equipment, including pumps. In addition, the roll of the ships causes a certain discomfort for the passengers, and is likely to cause seasickness. Also, in order to compensate the roll induced by the swell during the displacements of the ships, it is known to equip some of these ships of roll compensation devices. These compensation devices are intended to counterbalance the roll of the ship to solve the problems mentioned above.

Some of the known compensation devices rely on the addition of dedicated equipment at the hull of ships, and whose function is to slow the movement of rolling induced by waves. In addition, certain other compensation devices rely on the determination and transmission of compensation commands to the rudder or rudders of the rudder of the associated vessel.

However, the compensation devices mentioned above have disadvantages. Indeed, the addition of equipment dedicated to the compensation of the roll at the hull of the ships has the effect of increasing the resulting drag. In addition, modification of existing vessels for the introduction of compensation devices based on this principle of operation is expensive and difficult, if not impossible. As for them, the compensation devices based on the control of the rudders of the ships are relatively complex of operation. In particular, their operation is based on the implementation of equipment specifically dedicated to the control of the rudders for roll compensation and separate control equipment for the operation of the vessels in question. The invention aims in particular to overcome these disadvantages, by proposing an effective compensation device, simple to implement and does not require the addition of bulky equipment. For this purpose, the invention relates to a compensation device as described above, the compensation device comprising a processing device configured to determine values of two compensation instructions as a function of information of inclination of the ship around said longitudinal axis, the compensation instructions being intended to be applied by the first or the second propulsion unit respectively and being representative of a first or a second thrust differential intended to be added to the first and the second respectively. second thrust, the difference between the two corresponding thrust differentials being non-zero.

According to other aspects of the invention, the compensation device comprises one or more of the following technical characteristics, taken in isolation or in any technically possible combination: the compensation device is configured to determine the compensation instructions so that said compensation instructions correspond to thrust differentials of substantially equal absolute value and opposite signs; the compensation instructions correspond to thrust differentials whose difference is less than or equal to 5% of the value of the first and second thrusts; the inclination information comprises values of the inclination of the ship about said longitudinal axis during a predetermined period of time; and the processing device is configured to determine, at a given moment and for a subsequent instant, an estimate of the value of the inclination of the ship at the following instant as a function of the inclination information at the given instant, to determine the compensation setpoints according to said estimate, and to control the propulsion blocks the application, at said later time, said compensation instructions. In addition, the invention relates to a vessel extending along a longitudinal axis and comprising at least two propulsion units adapted to generate a first, respectively a second thrust substantially parallel to the longitudinal axis and substantially equal to one another. other, characterized in that it comprises a compensation device according to any one of the preceding claims.

According to other aspects of the invention the ship comprises one or more of the following technical characteristics, taken (s) isolation (s) or any combination (s) technically possible (s): - each propulsion unit comprises a power unit the processing device of the compensation device being configured to modify the power respectively delivered by the engine block of each propulsion unit for the application of the compensation instructions; each propulsion unit comprises a propeller with adjustable pitch, the processing device being configured to modify the pitch of the propeller of each propulsion unit for the application of the compensation instructions; each propulsion unit comprises a propulsion system adapted to generate a thrust by rejecting a jet of water and comprising a turbine and a steerable baffle for the modification of the orientation of the corresponding water jet; compensation device being configured to change the speed of rotation of each turbine and / or the inclination of each of the deflectors orientable about an axis substantially parallel to a pitch axis of the ship for the application of the compensation instructions; and - the longitudinal axis corresponds to the roll axis of the ship, the inclination of the ship relative to the longitudinal axis corresponding to the roll of the ship.

Finally, the invention relates to a method for compensating for the roll of a ship by means of a roll compensation device as defined above in which: - compensation instructions are determined according to information from inclination of the ship about the longitudinal axis, the compensation instructions being both respectively representative of a thrust differential to be applied by one of the propulsion units, the difference between the two thrust differentials being non-zero, and the propulsion blocks are controlled by the application of the compensation instructions. The invention will be better understood on reading the detailed description which follows, given solely by way of example and with reference to the appended figures in which: FIG. 1 is a diagrammatic illustration of a ship comprising a roll compensation according to the invention; Figure 2 is a schematic illustration of propulsion blocks of the ship of Figure 1 according to a first embodiment of the invention; FIG. 3 is a schematic illustration of propulsion blocks of the ship of FIG. 1 according to a variant of the invention; and - Figure 4 is a block diagram illustrating the operation of the compensation device of Figure 1.

Figure 1 illustrates a ship 2 according to the invention. The ship 2 extends along a longitudinal axis designated by the reference R in FIG. 1. The axis R corresponds to the roll axis of the ship 2. The inclination of the ship 2 around the axis R, c ' that is to say its roll, is denoted r in FIG. 1. The roll axis R is one of the three axes of an inertial reference frame 3 conventionally used in the maritime domain and comprising the roll axis R, the pitch axis T and the yaw axis L. The roll r then corresponds to the inclination of the plane containing the axes L and R with respect to a vertical plane. The ship 2 comprises a first propulsion unit 4, a second propulsion unit 6, and a compensation device 8 according to the invention, hereinafter device 8. The propulsion units 4, 6 are located at the rear of the vessel 2 and are offset laterally on either side of the longitudinal axis R. For example, the propulsion units 4, 6 are arranged symmetrically with respect to the plane containing the axes L and R. The first 4 and second 6 blocks of propulsion, hereinafter first block 4 and second block 6, are adapted to generate a first thrust P1, respectively a second thrust P2 both substantially parallel to the longitudinal axis R. Note that in practice, the first P1 and second P2 thrusts respectively correspond to the longitudinal component of the propulsion generated by the first block 4 and the second block 6. The thrusts P1 and P2 are setbacks resulting from the application by the propulsion blocks 4, 6 of propulsion instructions.

Referring to Figure 2, in some embodiments, the first and second blocks 4, 6 comprise a motor block 10, respectively 12, configured to move a propeller 14, respectively 16. The propellers 14, 16 are propellers with adjustable steps. In other words, each helix comprises steerable blades around the respective axis along which each of these blades extends. In known manner, at equal speed of rotation, two different pitch of a helix from each other will not result in different resultant thrusts. As a variant, with reference to FIG. 3, the first and second blocks 4, 6 each comprise a jet propulsion system 18, 20, also known as a "hydrojet". For its operation, each system 18, 20 is adapted to generate a thrust by acceleration of a quantity of water received in this system, then by rejecting this water in the form of a jet of water 22, 24 respectively. In addition, the systems 18, 20 each comprise a turbine 23, 25 and a baffle 26, 28 which can be rotated to modify the orientation of the corresponding water jet 22, 24, the attitude of the ship 2, that is to say say its orientation with respect to the axes of the reference frame 3, and the displacement of the ship. In particular, the deflectors 26, 28 are respectively inclinable relative to an axis substantially parallel to the pitch axis T of the ship 2, these axes being denoted T1, respectively T2 in Figure 3. The device 8 is configured to control the propulsion blocks 4, 6 so that the roll of the ship 2 is compensated. Preferably, the device 8 is configured to compensate for the roll of the ship 2 in a cruising configuration of the ship 2, in which the thrusts P1, P2 of the ship 2 are substantially equal to each other and are both marked P. Referring to Figure 1, the device 8 includes a tilt sensor 30 and a processing device 32. The tilt sensor 30 is configured to determine the value of the roll r of the vessel 2 over time, and to communicate roll information representative of the roll value r at the processing device 32. The inclination sensor 30 is of a type known per se. For example, the tilt sensor 30 includes a gyroscope. The processing device 32 is configured to modify the thrusts P1, P2 generated by the blocks 4, 6 in order to compensate for the roll induced by the swell. More specifically, the processing device 32 is configured to determine compensation setpoint values C1, C2 for the propulsion units 4, 6 as a function of the roll information and to command the blocks 4, 6 to apply the compensation instructions. C1, C2.

The compensation instructions C1, C2 are respectively representative of a first thrust differential P1 c and a second thrust differential P2c respectively generated by one and the other of the propulsion units 4, 6. The first differential of P1 thrust c is intended to be added to the first thrust P1. The second thrust differential P2c is intended to be added to the second thrust P2. The processing device 32 is adapted to determine the compensation setpoints C1, C2 such that the compensation instructions C1, C2 are representative of thrust differentials P1c, P2c whose difference is non-zero.

This has the effect that the application of the compensation instructions results in the relative braking of one side of the ship 2 relative to the other. This causes a modification of the hydrodynamic balance of the boat which results in the compensation of the roll of the ship 2. More precisely, the application of the compensation instructions C1, C2 by the blocks 4, 6 causes a yaw of the ship 2 around the yaw axis L and changes the orientation of the ship 2 relative to the swell. The modification of the corresponding hydrodynamic equilibrium results in a correction torque applied to the ship, which counterbalances the roll induced by the swell. As described below, the compensation instructions Ci, C2 are thus determined so that the hydrostatic equilibrium resulting from their application by the propulsion units 4, 6 at the corresponding instant counterbalance the roll induced by the swell at this moment. .

Note that the correspondence between a thrust instruction and the resulting thrust generated by a propulsion unit is known per se. As will be seen later, the compensation instructions are determined in such a way that the difference between the thrust differentials P1c, P2c varies during a wave period, during which a wave moves in the direction of ship, go under the ship, and then move away from the ship. The compensation instructions are determined in such a way that the thrust differentials tend to align the roll axis R with the direction of movement of the wave considered during the wave period in question when the wave moves towards the ship , and to tend to misalign the roll axis R with this direction of movement of the wave as the wave moves away from the ship. The amplitude of the alignment and the misalignment of the roll axis R with the direction of movement of the swell results from the value of the difference between the thrust differentials P1c, P2c at each instant. In addition, the clearing instructions do not change the ship's course corresponding overall to the heading and speed of the ship.

Preferably, the processing device 32 is configured to determine the compensation setpoints C1, C2 such that the thrust differentials Pic, P2c are of non-zero difference. Preferably, the device 8 is configured to compensate for the roll induced by the swell by the sole application of the compensation setpoints C1, C2 and thus by the only modification of the longitudinal thrusts P1, P2 respectively provided by the propulsion units 4, 6. for example, the difference between the thrust differentials P1c and P2c is less than or equal to 10% of the value of the thrust P, or even less than or equal to 6%. This limits the impact of the implementation of the device 8 on the efficiency of the propulsion units 4, 6 without reducing the compensation performance of the device 8.

Preferably, the processing device 32 is configured to determine the compensation setpoints C1, C2 such that the thrust differentials P1c, P2c have respective absolute values substantially equal to each other and equal to Pc, and opposite signs. This has the effect of simplifying the operation of the device 8 insofar as the number of calculations for obtaining the compensation instructions C1, C2 is reduced overall. In addition, this minimizes the time required for the application of the compensation instructions C1, C2 by the propulsion units 4, 6 insofar as the modifications of the behavior of the propulsion units 4, 6 to be implemented for the compensation of the rolls are equitably distributed between the propulsion units 4, 6. In the corresponding embodiments, insofar as the thrusts P1 and P2 are substantially equal to one another and of value P, the application of the instructions of FIG. compensation C1, C2 results in a passage of the thrust P1 from the value P to the value P ± Pc, and a passage of the thrust P2 from the value P to the value P Pc. For the determination of the compensation set points C1, C2, the processing device 32 is configured to determine, at a given instant noted tc, and for a given subsequent time noted tc, an estimate of the value that the roll r will have. subsequent instant tc as a function of the roll information provided by the roll sensor 30 up to the given instant t0, to determine the compensation set points C1, C2 as a function of the estimate of the roll value r at the subsequent time tc, and to control the blocks 4, 6 the application, at said later time tc, clearing instructions C1, C2. With reference to FIG. 2, the control of the application of the compensation instructions C1, C2 is implemented by the command to the blocks 4, 6, by the processing device 32, of a modification of the power delivered by each alternatively, alternatively or simultaneously, the application of the compensation instructions C1, C2 is implemented by the control to the blocks 4, 6 of a modification of the pitch of the propellers 14, 16.

Alternatively, in the embodiment of FIG. 3, the application of the compensation instructions C1, C2 is controlled by the processing devices 32 to the blocks 4, 6 in the form of a modification of the speed of rotation of the turbines 23, 25, and / or a modification of the inclination of the deflectors 26, 28 with respect to the axes T1, respectively T2 relative to which the deflectors 26, 28 are inclinable.

Alternatively, the processing device 32 is adapted to determine the compensation set points C1, C2 so that one of the thrust differentials Pie, P2 is zero. In other words, in the corresponding embodiments, only one of the flares PI or P2 is modified for roll compensation by the device 8. Preferably, the roll information r used by the processing device 32 to estimate a rolling value and determining the compensating setpoints C1, C2 accordingly are representative of the roll values r determined by the sensor 30 over a period of time corresponding to a small number of swell periods and ending at the moment given to considered. This makes it possible to estimate in a reliable and simple way the value of the roll at a given instant. In known manner, the wave has a frequency corresponding to a period of the order of ten seconds, for example eight seconds. Also, for example, the roll information used to determine compensation instructions C1, C2 consists of roll values supplied by the sensor 30 for a period of time substantially equal to one or a few periods of waves, for example two periods of time. swell, and ending at the instant to which the compensation instructions C1, C2 are determined. In addition, preferably, the interval between the instant to determination of compensation setpoints C1, C2 and the instant tc of their application by the blocks 4, 6 is less than one second, and is for example a few tenths of a second . This has the effect that the application of the compensation instructions C1, C2 is almost immediate once they are determined. In addition, this ensures that the roll estimate from which the compensation instructions C1, C2 have been determined is viable and close to the actual value that the roll will have at the subsequent instant tc associated. The operation of a compensation device 8 according to the invention will now be described with reference to FIG. 4.

Initially and during the operation of the device 8, the ship 8 is in a cruising configuration in which the thrusts PI and P2 are substantially equal to each other. During a determination step 34, the roll sensor 30 continuously provides roll information representative of the roll values of the ship 2 over time to the processing device 32. At a time to which the longitudinal thrusts generated by the blocks 4, 6 are both substantially P, the processing device 32 determines, for a subsequent time tc, an estimate of the value of the roll at the instant tc and the compensation instructions C1, C2 from this estimate. The compensation instructions C1, C2 are respectively representative of the thrust differentials Pic, P2c respectively intended to be provided by the propulsion units 4, 6. The estimation of the roll value is made from the values provided by the sensor 30. during a lapse of time preceding the instant to and of a duration corresponding to one or a few periods of swell. During an application step 36 beginning at the instant tc corresponding, the processing device 32 controls the first and second blocks 4, 6 the application of compensation instructions C1, C2 for the generation of thrust differential Pic , P2c. In response, the first and second blocks 4, 6 modify the thrusts P1, P2. The flares P1, P2 then take the value P + Plc respectively P + P2c. As indicated above, the non-nullity of the difference between the two thrust differentials P1c, P2c has the effect of modifying the hydrostatic equilibrium of the ship 2 so that the roll of the ship 2 is compensated. Steps 34 and 36 are repeated continuously, that is to say that the processing device 32 determines at each instant compensation instructions C1, C2 associated at a later time from the roll information provided during the process. a period of time preceding the corresponding instant, and controls the application of these instructions to the associated subsequent time. In other words, the device 8 continuously compensates the roll r by the application of the thrust differentials Pic, P2c to the thrusts P1, P2 supplied propulsion blocks 4, 6 for the modification of the hydrodynamic equilibrium of the ship 2. For example in some embodiments, during operation of the device 8 over time, the processing device 32 is configured to determine the compensation set points C1, C2 so that the absolute value of the difference between the thrust differentials P1 c, P2c corresponding remains substantially equal to a given percentage of the thrust P, for example 6%, and so that the sign of this difference varies with a frequency determined according to the frequency of the swell. For example, the sign change frequency of the difference between the thrust differentials is twice the frequency of the swell, ie the difference changes twice in sign at each swell period. The device 8 according to the invention has several advantages. Indeed, it does not require the addition to the ship 2 of a large dedicated equipment, in particular the addition of protruding equipment at the hull of the ship 2, which would cause the increase in the resulting drag. In addition, the operating principle of the device 8 is based solely on propulsion considerations made by the blocks 4, 6 substantially parallel to the roll axis r of the ship. This has the advantage that the device 8 can be implemented on any vessel 2 provided with two propulsion units. In particular, this allows the easy installation of the device 8 on ships that were not initially equipped with roll compensation device. Moreover, the device 8 is suitable for any type of propulsion. Indeed, it has been found that the wave frequencies generally observed at sea impose the control of the blocks 4, 6 with a speed of variation of the thrusts by an order of magnitude lower than the maximum speed of variation of the behavior of the blocks 4, 6, in particular the maximum variation speed of the respective pitch of the propellers 14, 16, as well as the inclination of the deflectors 26, 28 which are equipped with the hydrojets. Consequently, the implementation of the devices does not require modification of the propulsion units which the ships are equipped with and on which the device 8 would be installed after the start of the operation of the ship 2. Maximum variation of standard helical pitch is 0.77s. However, a difference between the thrust differentials P1c, P2c of the order of 5% of the thrust P is for example obtained by the sole control of a differential between the pitch of the propellers 14, 16 of the order of 1 °. Since the swell has a period of the order of several seconds, it can be seen that the maximum variation rate of 0.77s is compatible with the rates of variation of the pitch of the helices required for the implementation of the device. according to the invention. In addition, the roll compensation via the device 8 according to the invention is based solely on the control of the propulsion units 4, 6, and does not require any particular control or power transmission equipment, as it is the case for compensation devices based on the rudder rudder control. In other embodiments, the embodiments described above and technically compatible with each other are combined.

Claims (11)

CLAIMS1.- Roll compensation device for a ship intended to be on board a ship (2) extending along a longitudinal axis (R) and comprising at least a first and a second propulsion unit (4, 6) adapted to generate a first, respectively a second thrust (P1, P2) substantially parallel to the longitudinal axis (R) and substantially equal to one another, the compensation device (8) being configured to compensate for the inclination (r) of the ship about said longitudinal axis (R), the compensation device comprising a processing device (32) configured to determine values of two compensation set points (C1, C2) as a function of inclination information of the ship about said longitudinal axis (R), the compensation instructions (C1, C2) being intended to be applied by the first and second propulsion units (4, 6) respectively and being representative of a first and a second a second thrust differential (P1c, P2c) for adding to the first (P1), respectively to the second thrust (P2), the difference between the two thrust differentials (P1c, P2c) corresponding being non-zero. 2. Compensation device according to claim 1, wherein the compensation device (8) is configured to determine the compensation setpoints such that said compensation setpoints correspond to value thrust differentials (P1 c, P2c). substantially equal and of opposite signs. 3.- compensation device according to claim 1 or 2, wherein the compensation instructions correspond to thrust differentials (P1 c, P2c) whose difference is less than or equal to 5% of the value of the first and second thrusts ( P1, P2, P). Compensation device according to any one of the preceding claims, wherein the inclination information comprises values of the inclination (r) of the ship about said longitudinal axis (R) during a predetermined period of time. . 5. Compensation device according to any one of the preceding claims, wherein the processing device (32) is configured to determine, at a given instant (t0) and for a subsequent instant (te), an estimate of the value the inclination (r) of the ship at the subsequent instant (te) according to the inclination information at the given instant (t0), to determine the compensation instructions (C1, C2) according to said estimate, and to control the propulsion blocks (4, 6) the application, at said subsequent instant (te), of said compensation instructions. 6.- vessel (2) extending along a longitudinal axis (R) and comprising at least two propulsion units (4, 6) adapted to generate a first, respectively a second thrust (P1, P2) substantially parallel to the longitudinal axis (R) and substantially equal to one another, characterized in that it comprises a compensation device (8) according to any one of the preceding claims. 7. A vessel (2) according to claim 6, wherein each propulsion unit (4, 6) comprises a motor unit (10, 12), the processing device (32) of the compensation device (8) being configured to modifying the power respectively delivered by the engine block (10, 12) of each propulsion unit for the application of the compensation instructions (C1, C2). 8. A ship (2) according to claim 6 or 7, wherein each propulsion unit comprises a propeller (14, 16) with adjustable pitch, the processing device (32) being configured to modify the pitch of the propeller ( 14, 16) of each propulsion unit for the application of the compensation instructions (C1, C2). 9. A vessel (2) according to claim 6 or 7, wherein each propulsion unit (4, 6) comprises a jet propulsion system (18, 20) adapted to generate thrust by rejecting a jet of water ( 22, 24) and comprising a steerable turbine (23, 25) and deflector (26, 28) for changing the orientation of the corresponding water jet, the compensation device processing device being configured to change the speed of rotation of each turbine (23, 25) and / or the inclination of each of the deflectors orientable about an axis (T1, T2) substantially parallel to a pitch axis (T) of the ship for the application of the instructions of compensation (C1, C2). 10.- ship (2) according to any one of claims 5 to 8, wherein the longitudinal axis (R) corresponds to the roll axis of the ship (2), the inclination of the ship relative to the longitudinal axis corresponding to the roll (r) of the ship. 11. A method for compensating the roll of a ship using a roll compensation device according to any one of claims 1 to 5, in which: - compensation instructions (C1, C2) are determined. ) as a function of the inclination information of the ship about the longitudinal axis (R), the compensation instructions (P1 c, P20) being respectively representative of a thrust differential (P1c, P2c) to be applied by one of the propulsion units (4, 6), the difference between the two thrust differentials (P1c, P2c) being non-zero, and the propulsion units are controlled by the application of the compensation instructions (C1, C2 ).