Motion control device and motion control method for ship
To provide a motion control device for a ship, which does not require adjustment of weights of an performance function, and is less liable to fail in control calculation by building optimization calculation only into a part of classical feedback control, the motion control device, which is configured to cause a ship, on which a plurality of outboard engines are installed, to cruise along a desired trajectory, includes: a trajectory generator configured to output a trajectory command; a controller configured to output a control force command based on the trajectory command and a sensor information group output from a sensor group provided for the ship; and a control force distributor configured to carry out, based on the control force command, optimization calculation for operation amounts required for the plurality of outboard engines in accordance with a constraint condition set in advance so as to output the operation amounts.
1. A motion control device for a ship comprising a plurality of outboard engines, the motion control device causing the ship to cruise along a desired trajectory, and comprising:
a trajectory generator configured to output a trajectory command;
a controller configured to output a control force command based on the trajectory command and a sensor information group output from a sensor group provided for the ship; and
a control force distributor configured to carry out, based on the control force command, optimization calculation for operation amounts required for the plurality of outboard engines in accordance with a constraint condition that is satisfied when an x-axis propulsion force operation amount is in a range from zero to a maximum propulsion force multiplied by a cosine value of a maximum steering angle, and a y-axis propulsion force operation amount is in a range from a negative value of the x-axis propulsion force operation amount multiplied by a tangent value of the maximum steering angle, to the x-axis propulsion force operation multiplied by the tangent value of the maximum steering angle.
2. The motion control device for the ship according to claim 1 , wherein the control force distributor comprises:
a distribution calculator configured to output a driving force signal based on the control force command;
a driving force selector configured to output an optimal driving force signal based on the driving force signal; and
an operation amount calculator configured to output the required operation amounts based on the optimal driving force signal.
3. A motion control device for a ship comprising a plurality of outboard engines, the motion control device causing the ship to cruise along a desired trajectory, and comprising:
a trajectory generator configured to output a trajectory command;
a controller configured to output a control force command based on the trajectory command and a sensor information group output from a sensor group provided for the ship; and
a control force distributor configured to carry out, based on the control force command, optimization calculation for operation amounts required for the plurality of outboard engines in accordance with a constraint condition set in advance so as to output the operation amounts,
wherein:
the control force distributor comprises a distribution calculator configured to output a driving force signal based on the control force command, a driving force selector configured to output an optimal driving force signal based on the driving force signal, and an operation amount calculator configured to output the required operation amounts based on the optimal driving force signal;
the plurality of outboard engines comprise a first outboard engine and a second outboard engine; and
the distribution calculator is configured to calculate, as the driving force signal, a solution F* for minimizing a performance function J in a normal form given by the following expression under at least one linear inequality constraint condition:
J
=
1
2
F
T
RF
-
f
T
CF
C
≡
[
1
0
1
0
0
1
0
1
L
y
-
L
x
-
L
y
-
L
x
]
f
=
[
X
f
Y
f
N
f
]
F
=
[
f
X
1
f
X
1
f
X
2
f
Y
2
]
where, in a body-fixed coordinate system,
X f represents an X-axis direction translational force command,
Y f represents a Y-axis direction translational force command,
N f represents a Z-axis direction rotation torque command,
f X1 represents a propulsion force operation amount in an X-axis direction directed to the first outboard engine,
f Y1 represents a propulsion force operation amount in a Y-axis direction directed to the first outboard engine,
f X2 represents a propulsion force operation amount in the X-axis direction directed to the second outboard engine,
f Y2 represents a propulsion force operation amount in the Y-axis direction directed to the second outboard engine,
R represents a positive semi-definite matrix, and
L X and L y represent distances in the X-axis direction and the Y-axis direction, respectively, from a center of gravity of the ship to a rotation center of each of the first outboard engine and the second outboard engine.
4. The motion control device for the ship according to claim 3 , wherein the driving force selector is configured to:
calculate an error norm given by the following expression for the driving force signal output from the distribution calculator:
( f −CF*) T ( f −CF*); and
carry out one of determining a solution F opt that minimizes the error norm to output the solution F opt as the optimal driving force signal and applying predetermined signal processing to the solution F opt in accordance with the error norm to output a result of the predetermined signal processing as the optimal driving force signal.
5. The motion control device for the ship according to claim 4 , wherein the operation amount calculator is configured to calculate a propulsion force and a steering angle, which are the operation amounts required for the plurality of outboard engines, in accordance with the optimal driving force signal output from the driving force selector, and to output the propulsion force and the steering angle as the required operation amounts.
6. A motion control method for a ship that comprises a plurality of outboard engines to cruise along a desired trajectory, the motion control method comprising:
outputting a control force command based on a trajectory command and a sensor information group output from a sensor group provided for the ship; and
carrying out, based on the control force command, optimization calculation for operation amounts required for the plurality of outboard engines in accordance with a constraint condition that is satisfied when an x-axis propulsion force operation amount is in a range from zero to a maximum propulsion force multiplied by a cosine value of a maximum steering angle, and a y-axis propulsion force operation amount is in a range from a negative value of the x-axis propulsion force operation amount multiplied by a tangent value of the maximum steering angle, to the x-axis propulsion force operation multiplied by the tangent value of the maximum steering angle.