Control device for a vehicle and vehicle

Abstract

Increasing the success rate of underwater operations from the surface SOLUTION: The controller 5 of the underwater sailing body 1 includes the advance command section 541 that outputs the thrust command C3 for advancing the underwater sailing body 1, and the rudder control section 55 that outputs the rudder command C4 for instructing the rudder angle of the rudder 4. The rudder controller 55 includes a swing start command section 551 that outputs the rudder command C4 for starting the swing of the rudder 4, a phase-difference-increase command section 552 that outputs a command for gradually delaying the phase difference between the swing torque T around the pitch-axis acting on the underwater sailing body 1 due to the swing of the rudder 4 and the swing around the pitch-axis generated in the underwater sailing body 1 moving forward, and a swing stop command section 553 that outputs the rudder command C4 for stopping the swing of the rudder 4 when a predetermined condition is satisfied.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a control device for a watercraft and a watercraft. [Background technology]

[0002] The movement of an underwater vehicle involves operations such as surfacing and submerging. Patent Documents 1 and 2 disclose technologies related to the submerging operation of an underwater vehicle. Patent Document 1 describes a ballast device for an autonomous underwater vehicle. For example, Patent Document 1 describes in detail the configuration and operation of the ballast device's inlet and outlet. Patent Document 2 describes an underwater vehicle equipped with two trim tanks. For example, Patent Document 2 describes how the underwater vehicle can be made heel-up and in up-trim or down-trim by adjusting the amount of water in the two trim tanks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-79068 [Patent Document 2] Japanese Patent Application Publication No. 10-86894 Summary of the Invention [Problem to be solved by the invention]

[0004] One example of a method for submerging an underwater vehicle is to use thrusters to move forward in a position where the front of the vehicle is lower than the rear in the direction of travel (called the "head-down position"). In the head-down position, the thrust of the thrusters is divided into a forward component and a vertical component. The vertical component of this thrust causes the underwater vehicle to submerge.

[0005] For example, assume a situation in which an underwater vehicle attempts to dive from the ocean surface into the water. As mentioned above, if the underwater vehicle is positioned head down, the front of the vehicle will be underwater, but the rear of the vehicle may be above the water surface. The rear of the underwater vehicle is equipped with thrusters and a rudder that generate propulsion. In other words, if the rear of the underwater vehicle is above the water surface, the thrusters and the rudder will also be above the water surface. As a result, the running and diving operations of the underwater vehicle will be impaired, and the diving operation from the water surface to the water may fail.

[0006] Therefore, the present invention provides a control device for a watercraft that can increase the success rate of submersion operations from the sea surface, and a watercraft equipped with the control device. [Means for solving the problem]

[0007] One form of the present invention is a control device for a watercraft equipped with a rudder that controls its pitch axis, comprising: a forward command unit that outputs a command to move the watercraft forward; and a rudder control unit that outputs a command to indicate the rudder angle. The rudder control unit has: a swing start command unit that outputs a command to start swaying the rudder; a phase delay command unit that outputs a command to gradually delay the phase of the torque fluctuations about the pitch axis acting on the watercraft due to swaying of the rudder, relative to the swing about the pitch axis that occurs in the advancing watercraft; and a swing stop command unit that outputs a command to stop swaying of the rudder when a predetermined condition is met.

[0008] This control device causes the rudder to oscillate when the vessel is moving forward. The phase delay command unit gradually delays the phase of the torque fluctuations around the pitch axis acting on the vessel due to the rudder oscillate relative to the oscillations around the pitch axis that occur on the advancing vessel, thereby gradually increasing the oscillations around the pitch axis that occur on the vessel. As a result, the vessel, which is moving forward on the sea surface while oscillating, can begin submerging. This increases the success rate of submerging operations from the sea surface.

[0009] In the above-described control device for a marine vessel, the command to start rudder swing output from the swing start command unit may swing the rudder so that the direction of the torque acting on the marine vessel about the pitch axis due to the rudder swing is opposite to the direction of the swing of the marine vessel about the pitch axis. According to this command, the rudder swing is started from a state in which the swing of the marine vessel is suppressed. As a result, the rudder swing can be started stably.

[0010] In the control device for the above-mentioned watercraft, the yaw start command unit may output a command to start yaw of the rudder when a condition is satisfied that the relative speed between the advancing watercraft and the waves exceeds a threshold value. This command allows the yaw period of the watercraft to approach the natural period of the watercraft.

[0011] In the above-described control device for a marine vessel, the command output by the phase delay command unit to gradually delay the phase of the torque fluctuation about the pitch axis may gradually delay the phase of the torque fluctuation about the pitch axis from a first state in which the direction of the torque about the pitch axis acting on the marine vessel due to rudder pitching is opposite to the direction of the oscillation of the marine vessel about the pitch axis, to a second state in which the direction of the torque about the pitch axis acting on the marine vessel due to rudder pitching is the same as the direction of the oscillation of the marine vessel about the pitch axis. This command causes the direction of the oscillation of the marine vessel to match the direction of the torque about the pitch axis acting on the marine vessel. As a result, the oscillation amplitude of the marine vessel can be increased.

[0012] In the control device for the above-mentioned underwater vehicle, the oscillation stop command unit may output a command to stop the oscillation of the rudder when a condition that the amplitude of the oscillation of the underwater vehicle about the pitch axis is smaller than a threshold value is satisfied. This command allows the underwater vehicle to submerge to a depth where the influence of waves is negligible.

[0013] Another embodiment of the present invention provides a vessel comprising a vessel body including a propulsion unit that generates thrust; a rudder mounted on the vessel body for controlling the attitude of the vessel body about a pitch axis; and a controller for controlling the operation of the propulsion unit and the rudder. The controller includes a forward command unit that outputs a command to move the vessel forward, and a rudder control unit that outputs a command to indicate the rudder angle. The rudder control unit includes a swing start command unit that outputs a command to start swinging the rudder, a phase delay command unit that outputs a command to gradually delay the phase of the torque fluctuation about the pitch axis acting on the vessel due to the rudder swing relative to the swing about the pitch axis occurring in the forward-moving vessel, and a swing stop command unit that outputs a command to stop the swinging of the rudder when a predetermined condition is satisfied. This vessel is equipped with the controller, which is the control device described above. Therefore, the vessel can increase the success rate of submersion operations from the sea surface.

[0014] A control device for a watercraft in yet another embodiment of the present invention includes a forward command unit that outputs a command to move the watercraft forward, a rudder control unit that outputs a command to indicate the rudder angle, and a speed processing unit that obtains information about the relative speed between the forward moving watercraft and waves. The rudder control unit outputs a command to set a rudder angle to generate torque about the pitch axis so that the forward end of the watercraft is lower than the aft end of the watercraft, provided that the relative speed is less than a threshold value.

[0015] The state in which the relative speed between the vessel and the waves is less than the threshold is known as surfing. In surfing, the vessel's restoring force to return to a horizontal position is weak, making it more likely to tilt. By starting a submersion operation in this state, the success rate of submersion from the surface of the sea can be increased.

[0016] A navigation body according to yet another embodiment of the present invention comprises a navigation body main body including a propulsion unit that generates thrust, a rudder mounted on the navigation body main body for controlling the attitude of the navigation body about a pitch axis, and a controller that controls the operation of the propulsion unit and the rudder. The controller has a forward command unit that outputs a command to move the navigation body forward, a rudder control unit that outputs a command to indicate the rudder angle, and a speed processing unit that obtains information about the relative speed between the forward-moving navigation body and waves. The rudder control unit outputs a command to set a rudder angle to generate torque about the pitch axis so that the forward end of the navigation body is lower than the aft end of the navigation body, provided that the relative speed is less than a threshold value. This navigation body is equipped with the controller, which is the control device described above. Therefore, the navigation body can increase the success rate of submersion operations from the sea surface. [Effects of the Invention]

[0017] According to the present invention, a control device for a watercraft capable of increasing the success rate of submersion operations from the sea surface, and a watercraft equipped with the control device for the watercraft are provided. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing the main components of the watercraft of the first embodiment. [Figure 2] FIG. 2 is a flowchart of the submersible operation executed by the controller of the first embodiment. [Figure 3] Figure 3(a) is a graph showing the vessel's rocking angle and rocking torque when the phase difference between the vessel's rocking angle and rocking torque is 0 degrees. Figure 3(b) is a diagram showing the vessel's state at a certain point in time in Figure 3(a). Figure 3(c) is a diagram showing the vessel's state at a different point in time in Figure 3(a) from that in Figure 3(b). [Figure 4] Figure 4(a) is a graph showing the state when the phase difference between the vessel's pitch angle and pitch torque is increased. Figure 4(b) is a diagram showing the vessel's state at a certain point in time in Figure 4(a). Figure 4(c) is a diagram showing the vessel's state at a different point in time in Figure 4(a) from that in Figure 4(b). [Figure 5] Figure 5(a) is a graph showing the state when the phase difference between the vessel's swing angle and swing torque is 180 degrees. Figure 5(b) is a diagram showing the vessel's state at a certain point in time in Figure 5(a). Figure 5(c) is a diagram showing the vessel's state at a different point in time in Figure 5(a) from that in Figure 5(b). [Figure 6] FIG. 6 shows the state of the underwater vehicle when it is submerged. [Figure 7] FIG. 7 is a functional block diagram of a controller provided in the underwater vehicle. [Figure 8] FIG. 8 is a flowchart of the submersible operation executed by the controller of the second embodiment. [Figure 9] Figures 9(a), 9(b), and 9(c) show the state of the watercraft when it is accelerating, while Figures 9(d) and 9(e) show the state of the watercraft when it is surfing. [Figure 10] Figure 10(a) shows the state of the vehicle just before it starts submerging, Figure 10(b) shows the state of the vehicle during submerging, and Figure 10(c) shows the state of the vehicle when it transitions to a state of navigating underwater. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0020] As shown in FIG. 1, the underwater vehicle 1 travels underwater in oceans, rivers, lakes, and other areas. The underwater vehicle 1 is used, for example, for exploring underwater resources. The underwater vehicle 1 can navigate along a predetermined route or an autonomously set route. The underwater vehicle 1 primarily comprises a vehicle body 2, a thruster 3, and multiple rudders 4. The vehicle body 2 forms the outer shell of the underwater vehicle 1 and provides an internal space for accommodating devices such as a controller 5 (described below). The thruster 3 is provided at one end of the vehicle body 2. In the following description, the end where the thruster 3 is provided is referred to as the "rear end," and the end opposite the rear end is referred to as the "front end." The thruster 3 generates a force along the roll axis AR of the vehicle body 2. Therefore, the thruster 3 allows the underwater vehicle 1 to move forward or backward.

[0021] A plurality of rudders 4 are further provided on the rear end side of the vehicle body 2. The rudders 4 generate torque around the roll axis AR, torque around the pitch axis AP, and torque around the yaw axis AY of the vehicle body 2 to the forward moving underwater vehicle 1. As a result, the underwater vehicle 1 can perform operations such as surfacing, submerging, and turning.

[0022] The underwater vehicle 1 further includes a controller 5, a speed sensor 6, and an attitude sensor 7. These devices are housed in a watertight space in the vehicle body 2. The speed sensor 6 acquires several pieces of speed data D6 related to the speed of the underwater vehicle 1. The speed sensor 6 then passes the acquired speed data D6 to the controller 5. The speed data D6 includes, for example, the absolute speed of the underwater vehicle 1 with respect to the water bottom and the relative speed of the underwater vehicle 1 with respect to the surrounding water. Even if the absolute speed of the underwater vehicle 1 is constant, the relative speed of the underwater vehicle 1 may change depending on the direction and speed of the water flow around the underwater vehicle 1. The attitude sensor 7 acquires attitude data D7 related to the angle of the underwater vehicle 1 about the roll axis AR, the angle about the yaw axis AY, and the angle about the pitch axis AP. Like the speed sensor 6, the attitude sensor 7 also passes the acquired attitude data D7 to the controller 5.

[0023] The controller 5 uses the speed data D6 and the attitude data D7 to generate a thruster command C3 for the thruster 3 and a rudder command C4 for the rudder 4. Then, the controller 5 outputs the thruster command C3 to the thruster 3 and the rudder command C4 to the rudder 4.

[0024] The main components of the underwater vehicle 1 are as described above, but explanations and illustrations of other components that make up the underwater vehicle 1, such as the built-in battery, will be omitted.

[0025] The underwater vehicle 1 can increase the success rate of its diving operation from the sea surface into the water by using the rudder 4. The operation of the rudder 4 is controlled by the controller 5. The specific content of the diving operation controlled by the controller 5 will be described in detail below.

[0026] <Submersion movement of the navigable vehicle> 2 is a flowchart showing several steps that constitute the submersible operation of the underwater vehicle 1. The controller 5 of this embodiment executes a navigation pattern that causes the underwater vehicle 1 to submerge from the ocean surface. The controller 5 causes the underwater vehicle 1, which has difficulty submerging on its own at the ocean surface, to submerge by utilizing ocean surface waves W and appropriately controlling the thrusters 3 and rudders 4 to amplify the vibration amplitude of the pitch motion. As a result, the probability that the underwater vehicle 1 will be able to submerge is improved.

[0027] Specifically, the submersible motion of the underwater vehicle 1 is achieved by controlling the rudder 4 to swing the underwater vehicle 1 around the pitch axis AP. This pitch axis AP passes through the center of buoyancy of the underwater vehicle 1. As a result of extensive research, the inventors have determined that a combination of forward motion and swinging motion around the pitch axis AP makes it easier for the underwater vehicle 1 to begin submerging. The submerging motion referred to here refers to the motion of the underwater vehicle 1 moving diagonally downward relative to the direction of travel (see Figure 6). The submerging motion of the underwater vehicle 1 is executed by the controller 5.

[0028] Here, the parameters and physical phenomena related to the submerged motion of the vehicle will be explained.

[0029] Graph G41 in FIG. 4(a) shows the vehicle roll angle NR of the underwater vehicle 1 around the pitch axis AP. The vehicle roll angle NR may be defined as the angle of the roll axis AR relative to the horizontal. In graph G41, a positive value indicates that the underwater vehicle 1 is swinging clockwise around the pitch axis AP. For example, the state of the underwater vehicle 1 indicated by vehicle roll angle NR41a on graph G41 is as shown in FIG. 4(b). In graph G41, a negative value indicates that the underwater vehicle 1 is swinging counterclockwise around the pitch axis AP. For example, the state of the underwater vehicle 1 indicated by vehicle roll angle NR41b is as shown in FIG. 4(c).

[0030] Graph G42 in FIG. 4(a) shows the oscillation torque T about the pitch axis AP acting on the underwater vehicle 1 by the rudder 4. In graph G42, a positive value indicates a state in which the oscillation torque T in the counterclockwise direction about the pitch axis AP is acting on the underwater vehicle 1 (see FIG. 4(b)). For example, the state of the underwater vehicle 1 in which the oscillation torque T42a is acting on the graph G42 is as shown in FIG. 4(b). In graph G42, a negative value indicates a state in which the oscillation torque T in the clockwise direction about the pitch axis AP is acting on the underwater vehicle 1 (see FIG. 4(c)). For example, the state of the underwater vehicle 1 in which the oscillation torque T42b is acting on the graph G42 is as shown in FIG. 4(c).

[0031] The "yaw phase difference PD" is the difference between graph G41 and graph G42. For example, when the yaw phase difference PD is as shown in FIG. 4(a), the direction of the yaw torque T42a is opposite to the direction of the vehicle yaw angle NR41a. The state in which the direction of the yaw torque T42a is opposite to the direction of the vehicle yaw angle NR41a can also be said to be a state in which the attitude of the underwater vehicle 1 about the pitch axis AP is attempted to be kept horizontal. This state is a control mode that is normally performed when the underwater vehicle 1 is traveling straight.

[0032] In contrast, FIG. 5(a) shows a state in which the "swing phase difference PD is 180 degrees." Therefore, as shown in FIG. 5(b), the state in which the "swing phase difference PD is 180 degrees" can be defined as a state in which the direction of the vessel's swing angle NR and the direction of the swing torque T are aligned. As shown in FIG. 5(b), the state in which the direction of the vessel's swing angle NR51a and the direction of the swing torque T52a are aligned can also be said to be a state in which the underwater vehicle 1 attempts to swing further about the pitch axis AP. This state is not a control mode that is normally performed when the underwater vehicle 1 is moving in a straight line.

[0033] Furthermore, we will point out some points to keep in mind when the underwater vehicle 1 is submerged. The point to keep in mind is the relationship between the period of oscillation that occurs in the underwater vehicle 1 and the natural period of the underwater vehicle 1 about the pitch axis AP. First, we assume that no oscillation torque T is acting on the rudder 4, and place the underwater vehicle 1 at rest on the sea surface. If waves W are present on the sea surface, the underwater vehicle 1 will oscillate about the pitch axis AP according to the period of these waves W. In other words, when the underwater vehicle 1 is at rest, the period of oscillation that occurs in the underwater vehicle 1 about the pitch axis AP (vehicle oscillation period NC) matches the period of the waves W.

[0034] Next, let us assume that the underwater vehicle 1 is moved forward in the opposite direction to the direction of travel of the waves W. In this case, the number of waves W that the underwater vehicle 1 receives per unit time increases. In other words, when the underwater vehicle 1 is moving forward toward the waves W, the apparent vehicle oscillation period NC becomes shorter than the period of the waves W. The apparent vehicle oscillation period NC depends on the forward speed of the underwater vehicle 1.

[0035] The underwater vehicle 1 has a natural period of oscillation about the pitch axis AP. The natural period depends on the overall length and mass of the underwater vehicle 1. As the forward speed of the underwater vehicle 1 increases, the vehicle oscillation period NC also shortens. Normally, the natural period of the underwater vehicle 1 is longer than the period WC of the waves W. Therefore, as the forward speed of the underwater vehicle 1 increases, the vehicle oscillation period NC gradually approaches the natural period of the underwater vehicle 1. In other words, the oscillation of the underwater vehicle 1 about the pitch axis AP approaches a so-called resonance state.

[0036] The oscillation torque T generated by the rudder 4 further increases the vehicle's oscillation angle NR about the pitch axis AP of the underwater vehicle 1. In other words, the oscillation period of the rudder 4 (rudder oscillation period RC) coincides with the vehicle's oscillation period NC. As the forward speed of the underwater vehicle 1 increases, the vehicle's oscillation period NC tends to shorten, and therefore, as the forward speed of the underwater vehicle 1 increases, the rudder oscillation period RC also gradually shortens. Therefore, it can be said that the rudder oscillation period RC is determined by the forward speed of the underwater vehicle 1 and the period WC of the waves W. In other words, it can be said that the rudder oscillation period RC is determined by the relative speed of the underwater vehicle 1 with respect to the waves.

[0037] Based on the parameters and physical phenomena related to the submersible operation of the underwater vehicle described above, the submersible operation of the underwater vehicle 1 will be specifically explained below in order.

[0038] First, the controller 5 moves the underwater vehicle 1 forward (S11). At this time, the controller 5 does not generate torque by the rudder 4. As a result, the underwater vehicle 1 oscillates according to its speed relative to the waves. The controller 5 controls the thruster 3 to accelerate the underwater vehicle 1 until it reaches a predetermined speed. While the underwater vehicle 1 is accelerating, the vehicle oscillation period NC gradually becomes shorter.

[0039] Next, the controller 5 obtains velocity data D6 from the velocity sensor 6. Then, the controller 5 obtains the relative velocity of the underwater vehicle 1 with respect to the wave W based on the velocity data D6 (S12). Then, the controller 5 determines whether the relative velocity has reached a velocity threshold value VS (S13). When the controller 5 determines that the relative velocity has not reached the velocity threshold value VS (S13: NO), the controller 5 controls the thrusters 3 to accelerate the underwater vehicle 1. When the controller 5 determines that a predetermined relative velocity has been reached (S13: YES), the controller 5 controls the thrusters 3 to maintain that relative velocity.

[0040] Next, the controller 5 starts the swing of the rudder 4 (S14). The controller 5 obtains attitude data D7 relating to the swing of the underwater vehicle 1 about the pitch axis AP from the attitude sensor 7. From this attitude data D7, the controller 5 obtains a waveform (graph G31) showing the swing of the underwater vehicle 1, as shown in FIG. 3(a) and other figures. The controller 5 then obtains the vehicle swing period NC from the waveform (graph G31). The controller 5 then starts the swing of the rudder 4, starting from the initial state where the aforementioned "swing phase difference PD is zero." Specifically, the controller 5 matches the rudder swing period RC to the vehicle swing period NC. This match does not need to be a perfect match. A match can be considered to occur when the rudder swing period RC is within a preset allowable numerical range for the vehicle swing period NC. Furthermore, the controller 5 sets the rudder swing phase so that the swing phase difference PD, which is the difference between the vehicle swing phase and the rudder swing phase, is zero.

[0041] As a result, the oscillation of the underwater vehicle 1 and the oscillation of the rudder 4 are related as shown in graphs G31 and G32 in FIG. 3(a) and are in the states shown in FIGS. 3(b) and 3(c). For example, in FIG. 3(a), the state of the underwater vehicle 1 in state S3a is shown in FIG. 3(b). When the vehicle oscillation angle NR is at its maximum in the clockwise direction (NR31a), the oscillation torque T about the pitch axis AP by the rudder 4 is at its maximum in the counterclockwise direction (T32a). For example, in FIG. 3(b), the state of the underwater vehicle 1 in state S3b is shown in FIG. 3(c). When the vehicle oscillation angle NR is at its maximum in the counterclockwise direction (NR31b), the oscillation torque T about the pitch axis AP by the rudder 4 is at its maximum in the clockwise direction (T32b). In other words, the controller 5 operates to suppress the oscillation of the underwater vehicle 1 caused by the waves W.

[0042] In the above description, a mode has been described in which the timing at which the rudder 4 starts to swing does not overlap with the acceleration period of the underwater vehicle 1. For example, the timing at which the rudder 4 starts to swing may overlap with the acceleration period of the underwater vehicle 1. In other words, the rudder 4 may start to swing while the underwater vehicle 1 is accelerating. In this case, the rudder swing period RC may be gradually shortened to correspond to the acceleration of the underwater vehicle 1.

[0043] Next, the controller 5 gradually increases the rudder 4's oscillation phase difference PD (S15). Specifically, the controller 5 gradually delays the rudder oscillation phase relative to the vessel oscillation phase. Figure 4(a) shows the vessel oscillation angle NR (graph G41) and oscillation torque T (graph G42) during the period when the rudder oscillation phase is gradually delayed relative to the vessel oscillation phase.

[0044] Next, the controller 5 determines whether the yaw phase difference PD of the rudder 4 has reached 180 degrees (S16). When the controller 5 determines that the yaw phase difference PD of the rudder 4 has not reached 180 degrees, the controller 5 continues to gradually increase the yaw phase difference PD (S15). When the controller 5 determines that the yaw phase difference PD has reached 180 degrees, the controller 5 maintains the state in which the rudder yaw phase is shifted by 180 degrees from the vessel yaw phase (S17).

[0045] When the yaw phase difference PD of the rudder 4 reaches 180 degrees, the yaw of the underwater vehicle 1 and the yaw of the rudder 4 become as shown in the relationship shown in graphs G51 and G52 in FIG. 5(a) and as shown in FIGS. 5(b) and 5(c). For example, in FIG. 5(b), the state of the underwater vehicle 1 in state S5a is shown in FIG. 5(b). When the vehicle yaw angle NR is at its maximum in the clockwise direction (NR51a), the yaw torque T about the pitch axis AP due to the rudder 4 is at its maximum in the clockwise direction (T52a). For example, in FIG. 5(a), the state of the underwater vehicle 1 in state S5b is shown in FIG. 5(c). When the vehicle yaw angle NR is at its maximum in the counterclockwise direction (NR51b), the yaw torque T about the pitch axis AP due to the rudder 4 is at its maximum in the counterclockwise direction (T52b).

[0046] Next, the controller 5 determines whether the vessel rolling amplitude NA has become smaller than the amplitude threshold NAS (S18). If the controller 5 determines that the vessel rolling amplitude NA is not smaller than the amplitude threshold NAS (S18: NO), the controller 5 continues to roll the rudder 4 with the rolling phase difference PD being 180 degrees (S17). If the controller 5 determines that the vessel rolling amplitude NA is smaller than the amplitude threshold NAS (S18: YES), the controller 5 stops the rolling of the rudder 4 (S19). Then, the controller 5 controls the thrusters 3 and rudder 4 so as to move forward while maintaining a predetermined diving depth.

[0047] That is, the controller 5 uses the vehicle's pitch amplitude NA as a condition for determining whether to stop the yaw of the rudder 4. As already mentioned, the yaw of the underwater vehicle 1 is caused by the waves W received by the underwater vehicle 1 and the yaw torque T about the pitch axis AP by the rudder 4. As the submerged depth of the underwater vehicle 1 increases, the effect of the waves W on the yaw of the underwater vehicle 1 decreases. For example, when a certain submerged depth is reached, the effect of the waves W on the yaw of the underwater vehicle 1 can be considered to be zero. Then, as shown in Figure 6, as the submerged depth of the underwater vehicle 1 gradually increases, the vehicle's pitch amplitude NA also decreases. Finally, the yaw of the underwater vehicle 1 is caused only by the effect of the yaw of the rudder 4. Therefore, when the vehicle's pitch amplitude NA becomes smaller than a predetermined amplitude threshold NAS, it can be determined that the vehicle has reached a depth at which the effect of the waves W is considered to be zero. This amplitude threshold NAS may be a value obtained by subtracting the vessel oscillation amplitude NA just before submerging due to waves W and rudder 4 oscillation, from the vessel oscillation amplitude NA before rudder 4 oscillation due to waves W alone begins.

[0048] The condition for stopping the swing of the rudder 4 may be a condition other than the above-mentioned vehicle swing amplitude NA. For example, if the underwater vehicle 1 is equipped with a depth sensor, the depth data obtained from the depth sensor may be used as the condition for stopping the swing of the rudder 4.

[0049] <Controller 5> Next, the controller 5 that executes the submersible operation of the underwater vehicle 1 described above will be described. As shown in Fig. 7, the controller 5 is a computer equipped with a processor 5P, a memory 5M, and the like. The controller 5 further includes an input unit 5P1 that receives speed data D6 and attitude data D7, and an output unit 5P2 that outputs a thruster command C3 and a rudder command C4. The controller 5 may include other components according to required functions.

[0050] The processor 5P executes the submersible operation program PG stored in the memory 5M. As a result, the processor 5P realizes several functional components for the submersible operation. The processor 5P functions as a main control unit 51, a speed processing unit 52, an attitude angle processing unit 53, a thruster control unit 54, and a rudder control unit 55.

[0051] The main control unit 51 sets, for example, a movement route for the underwater vehicle 1. This movement route includes position information indicated by latitude and longitude, and depth information for the underwater vehicle 1. The main control unit 51 may determine the movement route for the underwater vehicle 1 according to a target set in advance. The main control unit 51 issues commands to the thruster control unit 54 and the rudder control unit 55 so that the underwater vehicle 1 moves along the set movement route. In addition, the main control unit 51 may execute all other controls necessary for the operation of the underwater vehicle 1.

[0052] The speed processing unit 52 obtains several pieces of speed information using the speed data D6 received from the speed sensor 6. For example, the speed processing unit 52 obtains the relative speed of the underwater vehicle 1 with respect to the waves. The speed processing unit 52 may also obtain the absolute speed of the underwater vehicle 1 with respect to the bottom of the water. The speed processing unit 52 may obtain the speed data D6 directly from the speed sensor 6, or may read and process the speed data D6 stored in the memory 5M from the speed sensor 6. The speed processing unit 52 stores the relative speed and the absolute speed in the memory 5M.

[0053] The attitude angle processing unit 53 obtains data on the vessel's pitch angle NR (see FIG. 3(a) and other figures) using the attitude data D7 received from the attitude sensor 7. The attitude angle processing unit 53 also obtains the vessel's pitch period NC from the vessel's pitch angle NR data. As with the speed processing unit 52, the attitude angle processing unit 53 may obtain the attitude data D7 directly from the attitude sensor 7, or may read and process the attitude data D7 stored in memory 5M from the attitude sensor 7.

[0054] The thruster control unit 54 generates a thruster command C3 to be given to the thruster 3 in response to a command received from the main control unit 51. The thruster control unit 54 gives the thruster command C3 to the thruster 3 via the output unit 5P2. The thruster control unit 54 includes a forward movement command unit 541. The forward movement command unit 541 generates the thruster command C3 for moving the underwater vehicle 1 forward.

[0055] The rudder control unit 55 includes a sailing command unit 55A and a submerged sailing command unit 55B. The sailing command unit 55A generates a rudder command C4 to realize the attitude instructed by the command of the main control unit 51. The rudder command C4 includes, for example, information regarding the rudder angle of the rudder 4.

[0056] The submergence command unit 55B is a functional element related to the submergence operation of the above-described underwater vehicle 1. The submergence command unit 55B includes a swing start command unit 551, a phase difference increase command unit 552, and a swing stop command unit 553.

[0057] The oscillation start command unit 551 executes the operation (S14) of starting the oscillation of the rudder 4, which was described in the submerging operation of the underwater vehicle 1. The phase difference increase command unit 552 executes the operation (S15) of gradually increasing the oscillation phase difference PD of the rudder 4, which was described in the submerging operation of the underwater vehicle 1. Furthermore, the phase difference increase command unit 552 executes the operation (S16) of determining whether the oscillation phase difference PD of the rudder 4 has reached 180 degrees. The oscillation stop command unit 553 executes the operation (S18) of determining whether the vessel oscillation amplitude NA, which was described in the submerging operation of the underwater vehicle 1, has become smaller than the amplitude threshold value NAS.

[0058] <Action and effect> The underwater vehicle 1 comprises a vehicle body 2 including thrusters 3 that generate thrust, a rudder 4 that is mounted on the vehicle body 2 and controls the attitude of the vehicle body 2 about the pitch axis AP, and a controller 5 that controls the operation of the propulsion unit and the rudder 4. The controller 5 comprises a forward command unit 541 that outputs a thruster command C3 to move the underwater vehicle 1 forward, and a rudder control unit 55 that outputs a rudder command C4 that commands the rudder angle of the rudder 4. The rudder control unit 55 comprises a swing start command unit 551 that outputs a rudder command C4 to start swinging the rudder 4, a phase difference increase command unit 552 that outputs a command to gradually delay the phase of fluctuations in the swing torque T about the pitch axis AP that acts on the underwater vehicle 1 due to the swing of the rudder 4, relative to the swing about the pitch axis AP that occurs in the advancing underwater vehicle 1, and a swing stop command unit 553 that outputs a rudder command C4 to stop the swing of the rudder 4 when a predetermined condition is met.

[0059] The controller 5 causes the rudder 4 to oscillate when the underwater vehicle 1 is moving forward. The phase difference increase command unit 552 gradually delays the phase of the torque fluctuation about the pitch axis AP acting on the underwater vehicle 1 due to the oscillating of the rudder 4 relative to the oscillating about the pitch axis AP that occurs in the advancing underwater vehicle 1, thereby gradually increasing the oscillating about the pitch axis AP that occurs in the underwater vehicle 1. As a result, the underwater vehicle 1, which is moving forward on the sea surface while oscillating, can begin submerging. This can increase the success rate of submerging operations from the sea surface.

[0060] The rudder command C4 output by the swing start command unit 551 to start swinging the rudder 4 swings the rudder 4 so that the direction of the swing torque T about the pitch axis AP acting on the underwater vehicle 1 due to the swing of the rudder 4 becomes opposite to the direction of swing about the pitch axis AP of the underwater vehicle 1. According to this rudder command C4, swinging of the rudder 4 is started from a state in which swinging of the underwater vehicle 1 is suppressed. As a result, swinging of the rudder 4 can be started stably.

[0061] When the condition that the relative speed between the advancing underwater vehicle 1 and the waves W exceeds the speed threshold value VS is met, the oscillation start command unit 551 outputs a rudder command C4 to start the oscillation of the rudder 4. This command allows the vehicle oscillation period NC to approach the natural period of the underwater vehicle 1.

[0062] The rudder command C4 output by the phase difference enlargement command unit 552, which gradually delays the phase of the fluctuation of the oscillation torque T about the pitch axis AP, gradually delays the phase of the fluctuation of the oscillation torque T about the pitch axis AP from a first mode in which the direction of the oscillation torque T about the pitch axis AP acting on the underwater vehicle 1 due to the oscillation of the rudder 4 is opposite to the direction of the oscillation of the underwater vehicle 1 about the pitch axis AP, to a second mode in which the direction of the oscillation torque T about the pitch axis AP acting on the underwater vehicle 1 due to the oscillation of the rudder 4 matches the direction of the oscillation of the underwater vehicle 1 about the pitch axis AP. According to this rudder command C4, the direction of the oscillation of the underwater vehicle 1 matches the direction of the oscillation torque T about the pitch axis AP acting on the underwater vehicle 1. As a result, the oscillation amplitude NA of the vehicle can be enlarged.

[0063] When the condition that the vehicle oscillation amplitude NA is smaller than the amplitude threshold value NAS is satisfied, the oscillation stop command unit 553 outputs a rudder command C4 to stop the oscillation of the rudder 4. This rudder command C4 allows the underwater vehicle 1 to submerge to a depth where the influence of waves W can be ignored.

[0064] Second Embodiment The underwater vehicle 1 may use a different method of diving from the above to increase the success rate of diving from the sea surface. The diving operation shown in the first embodiment can be applied when the underwater vehicle 1 moves in the opposite direction to the traveling direction of the waves W. In other words, the diving operation shown in the first embodiment can be applied when the movement of the underwater vehicle 1 is what is called head waves. In contrast, the underwater vehicle 1 may also move in the same direction as the traveling direction of the waves W. When the underwater vehicle 1 moves in the same direction as the traveling direction of the waves W, this is called following waves. In the second embodiment, a diving operation that can be applied when the waves are following waves will be described.

[0065] The physical configuration of the underwater vehicle 1 that performs submersible operation in the second embodiment is the same as that of the underwater vehicle 1 in the first embodiment. Therefore, a description of the physical configuration of the underwater vehicle 1 will be omitted.

[0066] 8 is a flowchart showing several steps constituting the submersible operation of the underwater vehicle 1 of the second embodiment. In following waves, the restoring force required to return the underwater vehicle 1 to a horizontal position is small, making the underwater vehicle 1 prone to tilt. The inventors have come up with the idea that the success rate of submersible operation from the sea surface can be increased if the submersible operation is initiated when the vehicle is prone to tilt.

[0067] First, the controller 5 moves the underwater vehicle 1 forward (S21). As shown in Figures 9(a), 9(b), and 9(c), as the forward speed of the underwater vehicle 1 increases, the underwater vehicle 1 catches up with the virtual reference wave WS. In other words, the underwater vehicle 1 gradually approaches a following wave state.

[0068] Next, the controller 5 obtains the relative velocity of the underwater vehicle 1 with respect to the wave W based on the velocity data D6 (S22). The operation of obtaining this relative velocity is performed by the velocity processing unit 52. In the examples of Figures 9(c), 9(d), and 9(e), the position of the underwater vehicle 1 with respect to the virtual reference wave WS is maintained. In other words, the underwater vehicle 1 is proceeding at the same velocity as the reference wave WS. In this state, the velocity of the underwater vehicle 1 with respect to the water is zero.

[0069] The controller 5 then determines whether the underwater vehicle 1 is in a following wave state. Specifically, whether the underwater vehicle 1 is in a following wave state may be determined using the water speed of the underwater vehicle 1. The water speed of the underwater vehicle 1 is the relative speed described above. When the underwater vehicle 1 is in a following wave state, the relative speed (water speed) is zero. Therefore, the controller 5 determines whether the relative speed is zero (S23). Note that the "relative speed is zero" here is not limited to when the relative speed is strictly zero. A predetermined range of allowable values ​​including zero may be set, and the "relative speed is zero" may be determined when the relative speed falls within that range. The determination of whether the relative speed is zero is performed by the speed processing unit 52.

[0070] If the controller 5 determines that the relative speed is not zero (S23: NO), it continues the forward movement of the underwater vehicle 1. Then, after a predetermined period of time has elapsed, it again determines whether the relative speed is zero (S23).

[0071] If the controller 5 determines that the relative velocity is zero (S23: YES), it changes the rudder angle of the rudder 4. Specifically, the controller 5 changes the rudder angle of the rudder 4 so that the underwater vehicle 1 assumes a so-called head-down attitude (S24: see FIG. 10(a)). When the rudder angle is changed as described above, the underwater vehicle 1, which is prone to tilting due to following waves, begins a submerged navigation operation (see FIG. 10(b)). This operation of changing the rudder angle of the rudder 4 is performed by the rudder control unit 55.

[0072] Next, the controller 5 determines whether or not the target depth has been reached (S25). When the controller 5 determines that the target depth has not been reached (S25: NO), it continues the diving operation. Then, after a predetermined period has elapsed, it again determines whether or not the target depth has been reached (S25). When the controller 5 determines that the target depth has been reached (S25: YES), it stops the diving operation (see Figure 10(c)). The determination of whether or not the target depth has been reached may be performed by the main control unit 51. Then, the controller 5 returns the rudder angle of the rudder 4 to the initial position (S26). This initial position is a rudder angle of the rudder 4 that does not generate torque around the pitch axis AP. This change in rudder angle is performed by the rudder control unit 55.

[0073] <Action and effect> The controller 5 for the underwater vehicle 1 comprises a forward command unit 541 that outputs a command to move the underwater vehicle 1 forward, a rudder control unit 55 that outputs a rudder command C4 that indicates the rudder angle of the rudder 4, a speed processing unit 52 that obtains information regarding the relative speed between the forward moving underwater vehicle 1 and the waves W, and the rudder control unit 55 that outputs the rudder command C4 as a rudder angle to generate a torque T about the pitch axis AP that will cause the front end of the underwater vehicle 1 to be lower than the rear end of the underwater vehicle 1, provided that the relative speed becomes smaller than a threshold value.

[0074] The state in which the relative speed between the underwater vehicle 1 and the wave W is smaller than the threshold value is known as surfing. In the surfing state, the restoring force required to return the underwater vehicle 1 to a horizontal position is reduced, making the underwater vehicle 1 more likely to tilt. By commencing submersion in this state, the success rate of submersion from the sea surface can be increased.

[0075] <Modification> The control device for a watercraft and the watercraft of the present invention are not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention.

[0076] <Additional Notes> The control device for a vehicle and the vehicle disclosed herein can increase the success rate of submersible operations from the ocean surface, and such a control device and vehicle can carefully manage global marine resources and contribute to the effective management of marine protected areas. Therefore, the control device for a vehicle and the vehicle disclosed herein contribute to Goal 14 of the Sustainable Development Goals (SDGs) led by the United Nations. Goal 14 is to "Conserve and sustainably use the oceans, seas, and marine resources."

[0077] Furthermore, the present disclosure includes the following configurations.

[0078] The present disclosure provides: [1] "A control device for a watercraft equipped with a rudder that controls a pitch axis, a forward movement command unit that outputs a command to move the underwater vehicle forward; a rudder control unit that outputs a command to indicate the rudder angle of the rudder, The rudder control section a swing start command unit that outputs a command to start swinging the rudder; a phase delay command unit that outputs a command to gradually delay the phase of torque fluctuations about the pitch axis that act on the vessel due to the swing of the rudder, in response to swings about the pitch axis that occur in the vessel moving forward; and a swing stop command unit that outputs a command to stop the swing of the rudder when a predetermined condition is satisfied."

[0079] The present disclosure is [2] "A control device for a watercraft described in [1] above, wherein the command to start the rudder swing output by the swing start command unit swings the rudder so that the direction of the torque acting on the watercraft about the pitch axis due to the rudder swing is opposite to the direction of swing of the watercraft about the pitch axis."

[0080] The present disclosure is [3] "A control device for a watercraft described in [1] or [2] above, wherein the oscillation start command unit outputs a command to start oscillating the rudder when the condition that the relative speed between the advancing watercraft and the waves exceeds a threshold is met."

[0081] The present disclosure is [4] "A control device for a marine vessel described in any one of [1] to [3] above, wherein the command output by the phase delay command unit to gradually delay the phase of the torque fluctuation about the pitch axis gradually delays the phase of the torque fluctuation about the pitch axis from a first state in which the direction of the torque about the pitch axis acting on the marine vessel due to the rudder swing is opposite to the direction of the swing of the marine vessel about the pitch axis, to a second state in which the direction of the torque about the pitch axis acting on the marine vessel due to the rudder swing is the same as the direction of the swing of the marine vessel about the pitch axis."

[0082] The present disclosure is [5] "A control device for a watercraft described in any one of [1] to [4] above, wherein the oscillation stop command unit outputs a command to stop the oscillation of the rudder when the condition that the amplitude of the oscillation around the pitch axis of the watercraft is smaller than a threshold value is satisfied."

[0083] This disclosure [6] "A naval vessel body including a propulsion unit that generates thrust; a rudder provided on the vessel body for controlling the attitude of the vessel body about a pitch axis; a controller for controlling the operation of the propulsion unit and the rudder, The controller a forward movement command unit that outputs a command to move the underwater vehicle forward; a rudder control unit that outputs a command to indicate the rudder angle of the rudder, The rudder control section a swing start command unit that outputs a command to start swinging the rudder; a phase delay command unit that outputs a command to gradually delay the phase of torque fluctuations about the pitch axis that act on the vessel due to the swing of the rudder, in response to swings about the pitch axis that occur in the vessel moving forward; and a swing stop command unit that outputs a command to stop the swing of the rudder when a predetermined condition is satisfied.

[0084] The present disclosure provides a control device for a watercraft equipped with a rudder that generates torque to control the attitude around a pitch axis, a forward movement command unit that outputs a command to move the underwater vehicle forward; a rudder control unit that outputs a command to indicate the rudder angle of the rudder; a speed processing unit that obtains information about the relative speed between the advancing vessel and waves, The rudder control section a control device for a marine vessel, which, on the condition that the relative velocity becomes smaller than a threshold value, outputs a command to set the rudder angle to generate torque about the pitch axis such that the front end of the marine vessel is lower than the rear end of the marine vessel.

[0085] This disclosure [8] "A naval vessel body including a propulsion unit that generates thrust; a rudder provided on the vessel body for controlling the attitude of the vessel body about a pitch axis; a controller for controlling the operation of the propulsion unit and the rudder, The controller a forward movement command unit that outputs a command to move the underwater vehicle forward; a rudder control unit that outputs a command to indicate the rudder angle of the rudder; a speed processing unit that obtains information about the relative speed between the advancing vessel and waves, The rudder control unit outputs a command to set the rudder angle to generate torque about the pitch axis such that the front end of the watercraft is lower than the rear end of the watercraft, on the condition that the relative speed becomes smaller than a threshold value." [Explanation of symbols]

[0086] 1 Underwater vehicle 2 Vehicle body 3. Thruster (propulsion section) 4 Rudder 5 Controller 6 Speed ​​Sensor 7. Attitude Sensor 14 Goals 51 Main control unit 52 Speed ​​processing section 53 Attitude angle processing unit 54 Thruster control unit 55 Rudder control section 55A Navigation Command Department 55B Submarine Command 541 Forward command section 551 Swing Start Command Unit 552 Phase difference enlargement command unit (phase delay command unit) 553 Swing stop command unit AP Pitch axis AR Roll Axis C3 Thruster Command C4 Rudder command D6 Speed ​​Data D7 Attitude Data NA Vessel body oscillation amplitude NAS amplitude threshold NC Vehicle oscillation period NR, NR41a, NR41b, NR51a Vehicle swing angle PD oscillation phase difference RC rudder swing period T, T42a, T42b, T52a Swing torque W wave

Claims

1. A control device for a watercraft equipped with a rudder that controls a pitch axis, comprising: a forward movement command unit that outputs a command to move the underwater vehicle forward; a rudder control unit that outputs a command to indicate the rudder angle of the rudder, The rudder control section a swing start command unit that outputs a command to start swinging the rudder; a phase delay command unit that outputs a command to gradually delay the phase of torque fluctuations about the pitch axis that act on the vessel due to the swing of the rudder, in response to swings about the pitch axis that occur in the vessel moving forward; a swing stop command unit that outputs a command to stop the swing of the rudder when a predetermined condition is satisfied.

2. 2. A control device for a marine vessel as described in claim 1, wherein the command to start the rudder swing output by the swing start command unit swings the rudder so that the direction of the torque about the pitch axis acting on the marine vessel due to the rudder swing is opposite to the direction of the swing of the marine vessel about the pitch axis.

3. 2. The control device for a watercraft as described in claim 1, wherein the sway start command unit outputs a command to start swaying the rudder when a condition is met that the relative speed between the advancing watercraft and waves exceeds a threshold.

4. 2. The control device for a marine vessel described in claim 1, wherein the command output by the phase delay command unit to gradually delay the phase of the torque fluctuation about the pitch axis gradually delays the phase of the torque fluctuation about the pitch axis from a first state in which the direction of the torque about the pitch axis acting on the marine vessel due to the rudder swing is opposite to the direction of the swing of the marine vessel about the pitch axis, to a second state in which the direction of the torque about the pitch axis acting on the marine vessel due to the rudder swing is the same as the direction of the swing of the marine vessel about the pitch axis.

5. 2. The control device for a marine vessel according to claim 1, wherein the oscillation stop command unit outputs a command to stop the oscillation of the rudder when a condition is satisfied that the amplitude of the oscillation of the marine vessel about the pitch axis is smaller than a threshold value.

6. a vessel body including a propulsion unit that generates thrust; a rudder provided on the vessel body for controlling the attitude of the vessel body about a pitch axis; a controller for controlling the operation of the propulsion unit and the rudder, The controller a forward movement command unit that outputs a command to move the underwater vehicle forward; a rudder control unit that outputs a command to indicate the rudder angle of the rudder, The rudder control section a swing start command unit that outputs a command to start swinging the rudder; a phase delay command unit that outputs a command to gradually delay the phase of torque fluctuations about the pitch axis that act on the vessel due to the swing of the rudder, in response to swings about the pitch axis that occur in the vessel moving forward; and a swing stop command unit that outputs a command to stop the swing of the rudder when a predetermined condition is satisfied.

7. A control device for a watercraft equipped with a rudder that generates torque to control the attitude around a pitch axis, a forward movement command unit that outputs a command to move the underwater vehicle forward; a rudder control unit that outputs a command to indicate the rudder angle of the rudder; a speed processing unit that obtains information about the relative speed between the advancing vessel and waves, The rudder control section a control device for a marine vessel that, on the condition that the relative velocity becomes smaller than a threshold value, outputs a command to set the rudder angle to generate torque about the pitch axis such that the front end of the marine vessel is lower than the rear end of the marine vessel.

8. a vessel body including a propulsion unit that generates thrust; a rudder provided on the vessel body for controlling the attitude of the vessel body about a pitch axis; a controller for controlling the operation of the propulsion unit and the rudder, The controller a forward movement command unit that outputs a command to move the underwater vehicle forward; a rudder control unit that outputs a command to indicate the rudder angle of the rudder; a speed processing unit that obtains information about the relative speed between the advancing vessel and waves, the rudder control unit outputs a command to set the rudder angle to generate torque around the pitch axis such that the front end of the watercraft is lower than the rear end of the watercraft, on the condition that the relative speed becomes smaller than a threshold value.

Images