PROPULSION FORCE CONTROL APPARATUS

BACKGROUND OF THE INVENTION
Field of the Invention

This invention relates to a propulsion force control apparatus configured to control a propulsion force of a vessel.

Description of the Related Art

A known device controls a propulsion force of a vessel so that the vessel navigates at a target vessel speed. Such device is described in JP 2017-094945 A, for example. In the device described in JP 2017-094945 A, a target engine rotation speed is determined in accordance with a difference between a target vessel speed and an actual vessel speed, and feedback control is performed in accordance with the determined target engine rotation speed.

Vessel operators normally do not perform an operation of immediately recovering the vessel speed when the vessel speed temporarily changes due to turning, disturbance, or the like. However, as in the device described in JP 2017-094945 A, when the feedback control is continued during turning of the vessel, the propulsion force increases during the turning or immediately after the turning of the vessel, and there is a possibility that sudden acceleration or excessive speed recovery not intended by the vessel operator may occur.

SUMMARY OF THE INVENTION

An aspect of the present invention is a propulsion force control apparatus configured to control a propulsion force of a vessel. The apparatus includes: a prime mover configured to drive a propulsor configured to propel the vessel; a speed sensor configured to detect an actual vessel speed of the vessel or a rotation speed of the prime mover; and an electronic control unit including a processor and a memory coupled to the processor and configured to perform feedback control of the rotation speed of the prime mover based on a difference between the actual vessel speed and a target vessel speed or between the rotation speed and a target rotation speed. The processor interrupts the feedback control when a degree of change in the actual vessel speed or the rotation speed becomes equal to or greater than a predetermined degree.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features, and advantages of the present invention will become clearer from the following description of embodiments in relation to the attached drawings, in which:

FIG. 1 is a perspective view schematically illustrating an example of configuration of a vessel mounted with an outboard motor, to which a propulsion force control apparatus according to an embodiment of the present invention is applied;

FIG. 2 is a side view of the outboard motor in FIG. 1;

FIG. 3 is a view for explaining operation of an operation lever in FIG. 1;

FIG. 4 is a block diagram schematically illustrating an example of configuration of a main part of the propulsion force control apparatus according to the embodiment of the present invention;

FIG. 5A is a flowchart showing an example of feedback control interruption processing executed by the propulsion force control apparatus according to the embodiment of the present invention;

FIG. 5B is a flowchart showing another example of feedback control interruption processing executed by the propulsion force control apparatus according to the embodiment of the present invention;

FIG. 6 is a flowchart showing an example of feedback control resumption processing executed by the propulsion force control apparatus according to the embodiment of the present invention; and

FIG. 7 is a time chart showing an example of operation of the propulsion force control apparatus according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7. A propulsion force control apparatus according to the embodiment of the present invention controls a propulsion force of a vessel. Hereinafter, an example will be described in which the propulsion force of a vessel mounted with an engine outboard motor, in particular, is controlled via a throttle opening degree.

FIG. 1 is a perspective view schematically illustrating an example of the configuration of a vessel 2 mounted with an outboard motor 1, to which the propulsion force control apparatus according to the embodiment of the present invention is applied. FIG. 2 is a side view of the outboard motor 1. Hereinafter, for convenience, the up-down direction and the front-rear direction are defined as illustrated, and each part will be described according to this definition.

As illustrated in FIG. 1, the outboard motor 1 is attached to the stem of the vessel 2. As illustrated in FIG. 2, an engine 3 including, for example, a spark-ignited water-cooled gasoline engine is mounted on an upper part of the outboard motor 1. The engine 3 is arranged such that a crankshaft 4 extends in the up-down direction. The crankshaft 4 is provided with a crank angle sensor 4a that outputs a pulse signal with the rotation of the crankshaft 4. The rotation speed (engine rotation number NE) of the engine 3 can be calculated based on the pulse signal from the crank angle sensor 4a. The engine 3 includes an electric throttle valve 3a including, for example, a butterfly valve. By adjusting an opening degree (throttle opening degree) TH of the throttle valve 3a, the amount of intake air to the engine 3 is adjusted, and the rotation speed (engine rotation number NE) of the engine 3 is adjusted.

The crankshaft 4, which is an output shaft of the engine 3, is connected to a propeller 8 that propels the vessel 2 via a drive shaft 5 extending in the up-down direction, a shift mechanism 6, and a propeller shaft 7 extending in the front-rear direction. The propeller shaft 7 and the propeller 8 may be referred to as “propulsor” that is driven by the engine 3 to propel the vessel 2.

The shift mechanism 6 includes a forward bevel gear 6a and a reverse bevel gear 6b that engage with the drive shaft 5, a clutch 6c that connects and disconnects the forward bevel gear 6a or the reverse bevel gear 6b and the propeller shaft 7, and a shift rod 6d and a shift slider 6e. An upper end of the shift rod 6d is connected to an actuator 10 such as a motor via a reduction gear mechanism 9, and a lower end of the shift rod 6d is connected to the shift slider 6e.

The clutch 6c is driven by the actuator 10 via the shift rod 6d and the shift slider 6e, and switches the shift position of the shift mechanism 6 among a neutral position, a forward position, and a reverse position. When the shift position is switched to the forward position or the reverse position, the rotation of the engine 3 is transmitted to the propeller shaft 7 via the crankshaft 4, the drive shaft 5 and the shift mechanism 6, the propeller 8 rotates, and the vessel 2 is propelled in the forward direction or the reverse direction. By adjusting the throttle opening degree TH and adjusting the engine rotation number NE, the propulsion force of the vessel 2 is adjusted, and the vessel speed (actual vessel speed) V is adjusted.

As illustrated in FIG. 1, an operation panel in front of a cockpit of the vessel 2 is provided with an operation lever 11 operated by a vessel operator. The operation lever 11 can swing in the front-rear direction from the central neutral position.

FIG. 3 is a view for explaining the operation of the operation lever 11. As illustrated in FIG. 3, when the operation lever 11 is switched from the neutral position to the forward position in front, the shift mechanism 6 (actuator 10) in FIG. 2 is switched from the neutral position to the forward position. When the operation lever 11 is switched from the neutral position to the reverse position at the rear, the shift mechanism 6 is switched from the neutral position to the reverse position.

When the operation lever 11 switched to the forward position or the reverse position is further tilted forward or rearward, the throttle opening degree TH is adjusted in accordance with the operation amount on the operation lever 11, and the engine rotation number NE and the actual vessel speed V are adjusted. More specifically, in accordance with the operation amount of continuous operation on the operation lever 11 in a swing range corresponding to the forward position, that is, the lever opening degree of the operation lever 11, the throttle opening degree TH is adjusted in a range of 0% to 100%, and the engine rotation number NE and the actual vessel speed V are adjusted.

FIG. 4 is a block diagram schematically illustrating an example of the configuration of a main part of a propulsion force control apparatus (hereinafter, apparatus) 100 according to the embodiment of the present invention. The apparatus 100 mainly includes an electronic control unit 50. The electronic control unit 50 is mounted on the vessel 2 side near the cockpit, for example. The electronic control unit 50 may be mounted on the outboard motor 1 side, or may include an electronic control unit mounted on the vessel 2 side and an electronic control unit mounted on the outboard motor 1 side.

As illustrated in FIG. 4, the electronic control unit 50 includes a computer having a processor 51 such as a CPU, a memory 52 such as a ROM and a RAM, and other peripheral circuits. The electronic control unit 50 is connected with the operation lever 11, a function switch 12, and operation buttons 13a and 13b provided on the operation panel in front of the cockpit, and the throttle valve 3a (actuator) of the engine 3 of the outboard motor 1 attached to the stern. The electronic control unit 50 is also connected with the crank angle sensor 4a, a vessel speed sensor 14, a rudder angle sensor 15, a yaw rate sensor 16, a radar 17, a camera 18, and the like mounted on the vessel 2.

The vessel speed sensor 14 is mounted on the vessel 2 and detects the actual vessel speed (navigation speed) V of the vessel 2. The vessel speed sensor 14 receives a positioning signal from a positioning satellite such as a GPS, for example, measures an absolute position (latitude and longitude) of the vessel 2 based on the received positioning signal, and calculates the actual vessel speed (ground vessel speed) V based on a time-series positioning result. The vessel speed sensor 14 may be an acoustic sensor or an electromagnetic sensor that detects the actual vessel speed (log vessel speed) V of the vessel 2.

The rudder angle sensor 15 is mounted on the vessel 2 and detects a rudder angle θ of the vessel 2. The rudder angle sensor 15 detects an operation amount (steering angle) of, for example, a steering wheel as the rudder angle θ. The rudder angle sensor 15 may detect, as the rudder angle θ, a rotation angle (turning angle) about a vertical axis in the up-down direction of the outboard motor 1 (propeller shaft 7) with respect to the vessel 2.

The yaw rate sensor 16 is mounted on the vessel 2 and detects a yaw rate ω, which is a rotation angle speed about the vertical axis of the center of gravity of the vessel 2.

The radar 17 is mounted on the vessel 2 and detects the presence or absence of an object in front of the vessel 2 by irradiating the front of the vessel 2 with electromagnetic waves and detecting reflected waves.

The camera 18 is mounted on the vessel 2 and photographs the front of the vessel 2. By performing image processing such as binarization, edge detection, and feature amount extraction processing on an image photographed by the camera 18, it is possible to detect the presence or absence of an object in front of the vessel 2.

As illustrated in FIG. 1, near the operation lever 11 of the operation panel in front of the cockpit is provided with the function switch 12, which is operated by the vessel operator and commands enablement or disablement of a cruise mode for maintaining a target vessel speed V0 or a target engine rotation number NE0. The operation button 13a, which is pressed by the vessel operator to command an increase in the target vessel speed V0 or the target engine rotation number NE0, and the operation button 13b, which commands a decrease in the target vessel speed V0 or the target engine rotation number NE0, are provided.

In a state where the cruise mode is not enabled (state where the cruise mode is disabled), the processor 51 of the electronic control unit 50 controls the operation of the throttle valve 3a based only on the lever opening degree of the operation lever 11 and controls the throttle opening degree TH. For example, when the lever opening degree of the operation lever 11 is 20%, the operation of the throttle valve 3a is controlled so that the throttle opening degree TH becomes 20%.

When the function switch 12 commands enablement of the cruise mode, the processor 51 enables the cruise mode on condition that the actual vessel speed V or the engine rotation number NE is stable, and starts feedback control (e.g., PID control) of the throttle opening degree TH. More specifically, when enablement of the cruise mode for maintaining the target vessel speed V0 is commanded, the processor 51 starts feedback control on condition that an absolute value |ΔV| of a change amount ΔV of the actual vessel speed V in a predetermined time period (e.g., 2 seconds) is equal to or less than a predetermined value ΔV1 (e.g., 0.3 mph). Similarly, when enablement of the cruise mode for maintaining the target engine rotation number NE0 is commanded, the processor 51 starts feedback control on condition that an absolute value |ΔNE| of a change amount ΔNE of the engine rotation number NE in a predetermined time period (e.g., 2 seconds) is equal to or less than a predetermined value ΔNE1 (e.g., 100 rpm). The processor 51 uses, as the actual vessel speed V or the engine rotation number NE, a moving average value (e.g., a moving average value every 2 seconds) of a detection value by the vessel speed sensor 14 or the crank angle sensor 4a.

In a state where the cruise mode is enabled, the processor 51 performs feedback control of the throttle opening degree TH based on the lever opening degree from the operation lever 11 and the number of times of operation on the operation buttons 13a and 13b. More specifically, when none of the operation buttons 13a and 13b is pressed after the start of the cruise mode for maintaining the target vessel speed V0, the processor 51 sets the actual vessel speed V (e.g., 45 mph) at the start of the cruise mode as the target vessel speed V0, and performs feedback control of the throttle opening degree TH. Similarly, when none of the operation buttons 13a and 13b is pressed after the start of the cruise mode for maintaining the target engine rotation number NE0, the processor 51 sets the engine rotation number NE at the start of the cruise mode as the target engine rotation number NE0, and performs feedback control of the throttle opening degree TH. That is, the processor 51 performs feedback control of the throttle opening degree TH such that a difference (V0−V) between the actual vessel speed V and the target vessel speed V0, or a difference (NE0−NE) between the engine rotation number NE and the target engine rotation number NE0 becomes “0”.

When the operation button 13a is pressed after the start of the cruise mode for maintaining the target vessel speed V0, the target vessel speed V0 is increased by every predetermined amount (e.g., 0.2 mph) in accordance with the number of times of pressing on the operation button 13a and finely adjusted. Similarly, when the operation button 13a is pressed after the start of the cruise mode for maintaining the target engine rotation number NE0, the target engine rotation number NE0 is increased by every predetermined amount (e.g., 50 rpm) in accordance with the number of times of pressing on the operation button 13a and finely adjusted.

When the operation button 13b is pressed after the start of the cruise mode for maintaining the target vessel speed V0, the target vessel speed V0 is decreased by every predetermined amount (e.g., 0.2 mph) in accordance with the number of times of pressing on the operation button 13b and finely adjusted. Similarly, when the operation button 13b is pressed after the start of the cruise mode for maintaining the target engine rotation number NE0, the target engine rotation number NE0 is decreased by every predetermined amount (e.g., 50 rpm) in accordance with the number of times of pressing on the operation button 13b and finely adjusted.

Such fine adjustment of the target vessel speed V0 or the target engine rotation number NE0 is received up to a predetermined adjustment width (e.g., 2 mph or 500 rpm corresponding to 10 times of operation) corresponding to a predetermined number of times of operation on the operation buttons 13a and 13b.

When the lever opening degree (actual lever opening degree) of the operation lever 11 exceeds or falls below a pseudo lever opening degree corresponding to the current throttle opening degree TH after the start of the cruise mode, the cruise mode is disabled and the feedback control of the throttle opening degree TH ends. For example, after the cruise mode is started with an actual lever opening degree of 20%, when the actual lever opening degree exceeds 23% corresponding to the current throttle opening degree TH in a state where the throttle opening degree TH is finely adjusted to 23% in response to the operation on the operation button 13a, the cruise mode is disabled. Similarly, after the cruise mode is started with the actual lever opening degree of 20%, when the actual lever opening degree falls below 17% corresponding to the current throttle opening degree TH in a state where the throttle opening degree TH is finely adjusted to 17% in response to the operation on the operation button 13b, the cruise mode is disabled.

When the operation lever 11 is operated in the direction opposite to the fine adjustment direction by the operation buttons 13a and 13b after the start of the cruise mode, the cruise mode is immediately disabled. For example, after the cruise mode is started with the actual lever opening degree of 20%, when the operation lever 11 is operated in the reverse direction and the actual lever opening degree falls below 20% in a state where the throttle opening degree TH is finely adjusted in an increasing direction in response to the operation on the operation button 13a, the cruise mode is disabled. Similarly, after the cruise mode is started with the actual lever opening degree of 20%, when the operation lever 11 is operated in the reverse direction and the actual lever opening degree exceeds 20% in a state where the throttle opening degree TH is finely adjusted in a decreasing direction in response to the operation on the operation button 13b, the cruise mode is disabled.

When the cruise mode is disabled, the processor 51 controls the operation of the throttle valve 3a based only on the actual lever opening degree and controls the throttle opening degree TH.

As described above, during the cruise mode, feedback control is performed on the throttle opening degree TH, whereby the actual vessel speed V is maintained at the target vessel speed V0 or the engine rotation number NE is maintained at the target engine rotation number NE0.

When the vessel 2 turns during constant-speed navigation at a constant vessel speed or a constant engine rotation number, the vessel 2 or the propulsor (propeller 8) receives resistance of water, and thus the vessel speed or the engine rotation number may be temporarily rapidly reduced. Alternatively, temporary sudden deceleration or sudden acceleration may occur due to influence of disturbance such as a change in water area, a gust, or a towing wave from another vessel. In such a case, the vessel operator usually does not perform an operation of immediately recovering the vessel speed or the engine rotation number, and waits for the end of turning or elimination of disturbance.

However, when the feedback control is constantly performed, the throttle opening degree TH is changed in accordance with the change in the actual vessel speed V and the engine rotation number NE even if temporarily. For this reason, sudden acceleration or sudden deceleration may occur while being affected by turning or disturbance, or excessive speed recovery may occur after the turning is ended or after the disturbance is eliminated. As described above, when the behavior of the vessel 2 significantly different from that at the time of normal vessel operation by the vessel operator, that is, the behavior of the vessel 2 unintended by the vessel operator occurs, there is a possibility that the vessel operator or other passengers feel uncomfortable or anxious.

Therefore, in the present embodiment, the apparatus 100 is configured as follows so as to be able to prevent sudden acceleration, sudden deceleration, and excessive speed recovery not intended by the vessel operator by interrupting feedback control when the actual vessel speed V or the engine rotation number NE suddenly changes.

When the degree of change in the actual vessel speed V detected by the vessel speed sensor 14 during the cruise mode for maintaining the target vessel speed V0 becomes equal to or greater than a predetermined value, the processor 51 of the electronic control unit 50 interrupts the feedback control of the throttle opening degree TH based on the difference (V0−V) between the actual vessel speed V and the target vessel speed V0, and maintains or fixes the current control command value (throttle opening degree TH). Similarly, when the degree of change in the engine rotation number NE detected by the crank angle sensor 4a becomes equal to or greater than a predetermined value during the cruise mode for maintaining the target engine rotation number NE0, the processor 51 of the electronic control unit 50 interrupts the feedback control of the throttle opening degree TH based on the difference (NE0−NE) between the engine rotation number NE and the target engine rotation number NE0, and maintains or fixes the current control command value (throttle opening degree TH).

More specifically, the processor 51 interrupts the feedback control when the absolute value |ΔV| of the change amount ΔV of the actual vessel speed V in a predetermined time period (e.g., 2 seconds) becomes equal to or greater than a predetermined value ΔV2 during the cruise mode for maintaining the target vessel speed V0. Similarly, the processor 51 interrupts the feedback control when the absolute value |ΔNE| of the change amount ΔNE of the engine rotation number NE in a predetermined time period (e.g., 2 seconds) becomes equal to or greater than a predetermined value ΔNE2 during the cruise mode for maintaining the target engine rotation number NE0.

The predetermined value ΔV2 is larger than the adjustment width of the target vessel speed V0 commanded by the operation buttons 13a and 13b, that is, the adjustment width (e.g., 2 mph corresponding to 10 times of operation) corresponding to a predetermined number of times of operation on the operation buttons 13a and 13b. Similarly, the predetermined value ΔNE2 is larger than the adjustment width of the target engine rotation number NE0 commanded by the operation buttons 13a and 13b, that is, the adjustment width (e.g., 50 rpm corresponding to 10 times of operation) corresponding to a predetermined number of times of operation on the operation buttons 13a and 13b. Therefore, the feedback control is prevented from being interrupted against the intention of the vessel operator who finely adjusts the target vessel speed V0 or the target engine rotation number NE0 during the feedback control via the operation buttons 13a and 13b.

Alternatively, the processor 51 may interrupt the feedback control when an absolute value (|V0−V|) of the difference between the actual vessel speed V and the target vessel speed V0 becomes equal to or greater than a predetermined value ΔV3 during the cruise mode for maintaining the target vessel speed V0. Similarly, the processor 51 may interrupt the feedback control when an absolute value (|NE0−NE|) of the difference between the engine rotation number NE and the target engine rotation number NE0 becomes equal to or greater than a predetermined value ΔNE3 during the cruise mode for maintaining the target engine rotation number NE0. The predetermined value ΔV3 or ΔNE3 is determined in advance in accordance with, for example, the target vessel speed V0 or the target engine rotation number NE0, and is stored in the memory 52 of the electronic control unit 50.

Due to this, when the actual vessel speed V or the engine rotation number NE suddenly changes due to turning, disturbance, or the like, the feedback control is interrupted, and sudden acceleration, sudden deceleration, or excessive speed recovery not intended by the vessel operator is prevented.

The processor 51 may further interrupt the feedback control when the degree of change in the actual vessel speed V or the engine rotation number NE becomes equal to or greater than a predetermined value on condition that an absolute value |Δθ| of a change amount Δθ in a predetermined time period of the rudder angle θ detected by the rudder angle sensor 15 is equal to or greater than a predetermined value θ0. Alternatively, the processor 51 may interrupt the feedback control when the degree of change in the actual vessel speed V or the engine rotation number NE becomes equal to or greater than a predetermined value on condition that an absolute value |ω| of the yaw rate ω detected by the yaw rate sensor 16 is equal to or greater than a predetermined value ω0.

In this case, the interruption of the feedback control is permitted on condition that the vessel 2 is actually turning. For example, when the vessel 2 enters a water area with large water resistance from a water area with small water resistance, such as when the vessel 2 exits from the inside of a bay to the outside of the bay, the vessel 2 may suddenly decelerate. By continuing the feedback control except during turning, when there is a sudden change in the actual vessel speed V or the engine rotation number NE without turning, the throttle opening degree TH and the engine rotation number NE are immediately adjusted, and the actual vessel speed V is quickly recovered to the target vessel speed V0 or the engine rotation number NE is quickly recovered to the target engine rotation number NE0.

Instead of the condition that the vessel 2 is actually turning, the processor 51 may set a condition that there is an obstacle in front of the vessel 2 and the probability that the vessel 2 starts turning is high. In this case, the processor 51 interrupts the feedback control when the degree of change in the actual vessel speed V or the engine rotation number NE becomes equal to or greater than a predetermined value on condition that the object in front of the vessel 2 is detected by the radar 17 or the camera 18.

After interrupting the feedback control, the processor 51 resumes the feedback control when the actual vessel speed V or the engine rotation number NE is stabilized. More specifically, after interrupting the feedback control during the cruise mode for maintaining the target vessel speed V0, the processor 51 resumes the feedback control when the absolute value |ΔV| of the change amount ΔV of the actual vessel speed V in a predetermined time period (e.g., 2 seconds) becomes equal to or less than a predetermined value ΔV4 (e.g., 0.3 mph). Similarly, after interrupting the feedback control during the cruise mode for maintaining the target engine rotation number NE0, the processor 51 resumes the feedback control when the absolute value |ΔNE| of the change amount ΔNE of the engine rotation number NE in a predetermined time period (e.g., 2 seconds) becomes equal to or less than a predetermined value ΔNE4 (e.g., 100 rpm).

Due to this, when the actual vessel speed V or the engine rotation number NE becomes stable in association with the end of turning, elimination of disturbance, or the like, the feedback control is automatically resumed regardless of any operation. Since only the feedback control is interrupted in a state of maintaining the throttle opening degree TH, when the feedback control is resumed, the actual vessel speed V is automatically recovered to near the original target vessel speed V0 or the engine rotation number NE is recovered to near the original target engine rotation number NE0 regardless of any operation. By resuming the feedback control after the actual vessel speed V or the engine rotation number NE is stabilized, the hunting between the interruption and the resumption of the feedback control is prevented.

The predetermined values ΔV4 and ΔNE4, which are thresholds at the time of resuming the feedback control, may be the same as or different from the predetermined values ΔV1 and ΔNE|, which are thresholds at the time of enabling the cruise mode in accordance with the operation of the function switch 12 and starting the feedback control. In a case where the threshold at the time of resuming the feedback control and the threshold at the time of starting the feedback control are set to the same value, it is possible to ensure sufficient safety even when resuming the feedback control, similarly to when starting the feedback control, and possible to simplify the entire control.

FIGS. 5A and 5B are flowcharts showing an example of feedback control interruption processing executed by the processor 51 of the electronic control unit 50, and show an example of the feedback control interruption processing during the cruise mode for maintaining the target vessel speed V0. FIG. 6 is a flowchart showing an example of feedback control resumption processing executed by the processor 51 of the electronic control unit 50, and shows an example of the feedback control resumption processing during the cruise mode for maintaining the target vessel speed V0. The processing of FIGS. 5A to 6 is started when the electronic control unit 50 is activated, and is repeated at a predetermined cycle.

In the feedback control interruption processing shown in FIG. 5A, first, in S1 (S: processing step), it is determined whether or not the feedback control is being performed. When the determination is positive in S1, the process proceeds to S2, and when the determination is negative in S1, the process ends. In S2, it is determined whether or not the absolute value |ΔV| of the change amount ΔV of the actual vessel speed V in the predetermined time period is equal to or greater than the predetermined value ΔV2, or whether or not the absolute value (|V0−V|) of the difference between the actual vessel speed V and the target vessel speed V0 is equal to or greater than the predetermined value ΔV3. When the determination is positive in S2, the process proceeds to S3, and the feedback control is interrupted to fix the current throttle opening degree TH. When the determination is negative in S2, the process ends.

In the feedback control interruption processing shown in FIG. 5B, when the determination is positive in S2, the process proceeds to S10, and it is determined whether or not the absolute value |Δθ| of the change amount Δθ of the rudder angle θ in the predetermined time period is equal to or greater than the predetermined value θ0 or whether or not the absolute value |ω| of the yaw rate w is equal to or greater than the predetermined value ω0. When the determination is positive in S10, the process proceeds to S3, and the feedback control is interrupted to fix the current throttle opening degree TH. When the determination is negative in S10, the process ends.

In the control resumption processing shown in FIG. 6, first, in S20, it is determined whether or not the feedback control is being interrupted. When the determination is positive in S20, the process proceeds to S21, and when the determination is negative in S20, the process ends. In S21, it is determined whether or not the absolute value |ΔV| of the change amount ΔV of the actual vessel speed V in the predetermined time period is equal to or less than the predetermined value ΔV1. When the determination is positive in 521, the process proceeds to S22, and the feedback control is resumed. If the determination is negative in 521, the processing ends.

FIG. 7 is a time chart showing an example of the operation of the apparatus 100, showing whether the actual vessel speed V, the throttle opening degree TH, and the feedback control (FB) are enabled (ON) or disabled (OFF) when the vessel 2 turns in a state where the cruise mode for maintaining the target vessel speed V0 is enabled.

As shown in FIG. 7, when the vessel 2 starts turning at time t0, the resistance of water received by the vessel 2 gradually increases, whereby the actual vessel speed V gradually decreases and deviates from the target vessel speed V0. When the degree of change in the actual vessel speed V, that is, the deceleration or the degree of deviation of the actual vessel speed V from the target vessel speed V0 becomes equal to or greater than a predetermined value at time t1, the feedback control is interrupted and the throttle opening degree TH is fixed (S2 and S3 in FIGS. 5A and 5B). When the resistance of water received by the vessel 2 starts to decrease at time t2, the actual vessel speed V gradually recovers. When the actual vessel speed V becomes stable at time t3, that is, when the acceleration becomes equal to or less than a predetermined value, the feedback control is resumed, and the actual vessel speed V recovers to the target vessel speed V0 at time t4 (S21 and S22 in FIG. 6).

Although not illustrated, the same applies to the case where the vessel 2 turns in a state where the cruise mode for maintaining the target engine rotation number NE0 is enabled. That is, when the vessel 2 starts turning, the resistance of water received by the vessel 2 and the propulsor (propeller 8) gradually increases, whereby the engine rotation number NE gradually decreases and deviates from the target engine rotation number NE0. When the degree of change in the engine rotation number NE, that is, the change rate or the degree of deviation of the engine rotation number NE from the target engine rotation number NE0 becomes equal to or greater than a predetermined value, the feedback control is interrupted and the throttle opening degree TH is fixed. When the resistance of water received by the vessel 2 starts to decrease, the engine rotation number NE gradually recovers. When the engine rotation number NE is stabilized, the feedback control is resumed, and the engine rotation number NE recovers to the target engine rotation number NE0.

Note that due to a change in the water area or the like, the actual vessel speed V or the engine rotation number NE at the time of resuming the feedback control, that is, at the time point of stabilization may greatly fall below or exceed the target vessel speed V0 or the target engine rotation number NE0. Even in such a case, the actual vessel speed V recovers to the target vessel speed V0 or the engine rotation number NE recovers to the target engine rotation number NE0 by the resumed feedback control.

Thus, when the actual vessel speed V or the engine rotation number NE suddenly changes due to turning of the vessel 2, disturbance, or the like, the feedback control is interrupted until the actual vessel speed V or the engine rotation number NE is stabilized, and therefore sudden acceleration, sudden deceleration, or excessive speed recovery not intended by the vessel operator does not occur. Even when the feedback control is interrupted, since the cruise mode itself is maintained in the enabled state, it is not necessary to operate the function switch 12 for resuming the feedback control or to operate the operation buttons 13a and 13b for resetting the target vessel speed V0 or the target engine rotation number NE0.

According to the present embodiment, the following functions and effects can be achieved.

(1) The apparatus 100 controls the propulsion force of the vessel 2. The apparatus 100 includes the engine 3 that drives the propulsor (the propeller shaft 7 and the propeller 8) that propels the vessel 2, the vessel speed sensor 14 that detects the actual vessel speed V of the vessel 2 or the crank angle sensor 4a that detects the rotation speed (the engine rotation number NE) of the engine 3, and the electronic control unit 50 having the processor 51 and the memory 52 connected to the processor 51 and configured to perform feedback control of the throttle opening degree TH based on the difference (V0−V) between the actual vessel speed V and a target vessel speed V0 or the difference (NE0−NE) between the engine rotation number NE and the target engine rotation number NE0 (FIG. 4). When the degree of change in the actual vessel speed V or the engine rotation number NE becomes equal to or greater than a predetermined value, the processor 51 interrupts the feedback control (FIG. 5A, FIG. 5B, and FIG. 7).

When the actual vessel speed V or the engine rotation number NE suddenly changes due to turning, disturbance, or the like and the absolute value |ΔV| and |ΔNE| of the change amount ΔV and ΔNE of the actual vessel speed V or the engine rotation number NE in a predetermined time period becomes equal to or greater than the predetermined value ΔV2 or ΔNE2, or when the absolute value (|V0−V|) or (|NE0−NE|) of the difference between the actual vessel speed V and the target vessel speed V0 or the engine rotation number NE and the target engine rotation number NE0 becomes equal to or greater than the predetermined value ΔV3 or ΔNE3 although the feedback control is being performed, it is possible to prevent sudden acceleration, sudden deceleration, and excessive speed recovery not intended by the vessel operator by interrupting the feedback control.

(2) When the absolute value |ΔV| or |ΔNE| of the change amount ΔV or ΔNE of the actual vessel speed V or the engine rotation number NE in the predetermined time period becomes equal to or greater than the predetermined value ΔV2 or ΔNE2, the processor 51 interrupts the feedback control. When the actual vessel speed V or the engine rotation number NE suddenly changes due to turning, disturbance, or the like and the absolute value |ΔV| and |ΔNE| of the change amount ΔV and ΔNE of the actual vessel speed V or the engine rotation number NE in a predetermined time period becomes equal to or greater than the predetermined value ΔV2 or ΔNE2, it is possible to prevent sudden acceleration, sudden deceleration, and excessive speed recovery not intended by the vessel operator by interrupting the feedback control.

(3) When the absolute value (|V0−V|) or (|NE0−NE|) of the difference between the actual vessel speed V and the target vessel speed V0 or the engine rotation number NE and the target engine rotation number NE0 becomes equal to or greater than the predetermined value ΔV3 or ΔNE3, the processor 51 interrupts the feedback control. When the actual vessel speed V or the engine rotation number NE suddenly changes due to turning, disturbance, or the like and the absolute value (|V0−V|) or (|NE0−NE|) of the difference between the actual vessel speed V and the target vessel speed V0 or the engine rotation number NE and the target engine rotation number NE0 becomes equal to or greater than the predetermined value ΔV3 or ΔNE3 although the feedback control is being performed, it is possible to prevent sudden acceleration, sudden deceleration, and excessive speed recovery not intended by the vessel operator by interrupting the feedback control.

(4) The apparatus 100 further includes the operation buttons 13a and 13b that command adjustment of the target vessel speed V0 or the target engine rotation number NE0 in response to the operation of the vessel operator (FIGS. 1 and 4). The predetermined values ΔV2 and ΔNE2 are each larger than the adjustment width of the target vessel speed V0 or the target engine rotation number NE0 commanded by the operation buttons 13a and 13b. This can prevent the feedback control from being interrupted against the intention of the vessel operator who finely adjusts the target vessel speed V0 or the target engine rotation number NE0 during the feedback control via the operation buttons 13a and 13b.

(5) After interrupting the feedback control, the processor 51 resumes the feedback control when the actual vessel speed V or the engine rotation number NE is stabilized. Due to this, when the actual vessel speed V or the engine rotation number NE is stabilized due to the end of turning, elimination of disturbance, or the like, the feedback control is automatically resumed without any operation, and thus there is no operation burden on the vessel operator.

(6) After interrupting the feedback control, the processor 51 resumes the feedback control when the absolute value |ΔV| or |ΔNE| of the change amount ΔV or ΔNE of the actual vessel speed V or the engine rotation number NE in the predetermined time period becomes equal to or less than the predetermined value ΔV4 or ΔNE4. In this manner, by resuming the feedback control after the actual vessel speed V or the engine rotation number NE is stabilized, it is possible to prevent the hunting between the interruption and the resumption of the feedback control.

(7) The apparatus 100 further includes the function switch 12 for commanding enablement or disablement of the feedback control in response to the operation of the vessel operator, and the operation lever 11 for commanding the throttle opening degree TH in accordance with the operation amount of the vessel operator (FIGS. 1 and 4). When the feedback control is disabled, the processor 51 controls the throttle opening degree TH in accordance with the operation amount on the operation lever 11, and starts the feedback control on condition that the absolute value |ΔV| or |ΔNE| of the change amount ΔV or ΔNE of the actual vessel speed V or the engine rotation number NE in the predetermined time period is equal to or less than the predetermined value ΔV1 or ΔNE1 equal to the predetermined value ΔV4 or ΔNE4 when the function switch 12 commands the enablement of the feedback control. That is, even when the feedback control is resumed after the interruption, the same condition as that when the feedback control is started is provided. In this case, sufficient safety can be ensured even when the feedback control is resumed after the interruption, and the entire control can be simplified.

(8) When the degree of change in the actual vessel speed V or the engine rotation number NE becomes equal to or greater than a predetermined value, the processor 51 interrupts the feedback control and maintains the current control command value (throttle opening degree TH). In this way, when the feedback control is resumed by interrupting only the feedback control in a state of maintaining the throttle opening degree TH, the actual vessel speed V automatically recovers to near the original target vessel speed V0 or the engine rotation number NE automatically recovers to near the original target engine rotation number NE0 regardless of any operation.

(9) The apparatus 100 further includes the rudder angle sensor 15 that detects the rudder angle θ of the vessel 2 (FIG. 4). When the degree of change in the actual vessel speed V or the engine rotation number NE becomes equal to or greater than a predetermined value, the processor 51 interrupts the feedback control on condition that the absolute value |Δθ| of the change amount Δθ of the rudder angle θ in the predetermined time period is equal to or greater than the predetermined value θ0. In this case, for example, when the actual vessel speed V or the engine rotation number NE suddenly changes with a change in the water area, the throttle opening degree TH and the engine rotation number NE are immediately adjusted without interrupting the feedback control, and the actual vessel speed V quickly recovers to the target vessel speed V0 or the engine rotation number NE quickly recovers to the target engine rotation number NE0.

(10) The apparatus 100 further includes the yaw rate sensor 16 that detects the yaw rate ω of the vessel 2 (FIG. 4). When the degree of change in the actual vessel speed V or the engine rotation number NE becomes equal to or greater than a predetermined value, the processor 51 interrupts the feedback control on condition that the absolute value |ω| of the yaw rate w is equal to or greater than the predetermined value (o. In this case, for example, when the actual vessel speed V or the engine rotation number NE suddenly changes with a change in the water area, the throttle opening degree TH and the engine rotation number NE are immediately adjusted without interrupting the feedback control, and the actual vessel speed V quickly recovers to the target vessel speed V0 or the engine rotation number NE quickly recovers to the target engine rotation number NE0.

(11) The apparatus 100 further includes the radar 17 or the camera 18 that detects an object in front of the vessel 2 (FIG. 4). When the degree of change in the actual vessel speed V or the engine rotation number NE becomes equal to or greater than a predetermined value, the processor 51 interrupts the feedback control on condition that an object in front of the vessel 2 is detected by the radar 17 or the camera 18. In this case, when the actual vessel speed V or the engine rotation number NE suddenly changes in a situation where there is no obstacle in front, the throttle opening degree TH and the engine rotation number NE are immediately adjusted without interrupting the feedback control, and the actual vessel speed V quickly recovers to the target vessel speed V0 or the engine rotation number NE quickly recovers to the target engine rotation number NE0.

In the above embodiment, an example of adjusting the engine rotation number NE via the throttle opening degree TH to control the propulsion force of the vessel 2 has been described, but the propulsion force control apparatus is not limited to such an apparatus. For example, an engine whose engine rotation number is adjusted via the fuel injection amount may be used as a prime mover, and the engine rotation number may be adjusted via the fuel injection amount to control the propulsion force of the vessel 2. Alternatively, a motor may be used as a prime mover, and the propulsion force of the vessel 2 may be controlled via the motor rotation number.

In the above embodiment, FIG. 1 and the like give examples of the specific shape and arrangement of the operation lever 11, but the shape and arrangement of the operation lever for commanding the rotation speed of the prime mover in accordance with the operation amount of the vessel operator are not limited to those described above. In the above embodiment, FIG. 1 and the like give examples of the specific shape and arrangement of the function switch 12, but the shape and arrangement of the switch for commanding enablement or disablement of the feedback control in response to the operation of the vessel operator are not limited to those described above. In the above embodiment, FIG. 1 and the like give examples of the specific shape and arrangement of the operation buttons 13a and 13b, but the shape and the arrangement of the operation member that commands adjustment of the target vessel speed or the target rotation speed of the prime mover in response to the operation of the vessel operator are not limited to those described above.

The above embodiment can be combined as desired with one or more of the aforesaid modifications. The modifications can also be combined with one another.

According to the present invention, it becomes possible to prevent sudden acceleration, sudden deceleration, and excessive speed recovery not intended by the vessel operator.

Above, while the present invention has been described with reference to the preferred embodiments thereof, it will be understood, by those skilled in the art, that various changes and modifications may be made thereto without departing from the scope of the appended claims.

PROPULSION FORCE CONTROL APPARATUS

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