JPH0410980B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention measures the motion of a model such as a ship in a fluid by measuring forces in at least one of six directions,
Then, find the difference between the set value set on the load setting device and the fluid force, form a difference signal from this difference, input it to the servo system, drive the model by servo, and apply the above set value to the model of the ship etc. In order to move the model so that a force equilibrium state in which a force equal to and calculate the difference between the load and the set value set on the load setting device, form a difference signal from this difference, input this to the servo system, and set the servo so that the difference with the above set value becomes zero. The present invention relates to a motion restraint device for recording the servo-driven movement of a model by servo-driving the model using a system, and analyzing this to be useful in designing a ship or the like suitable for desired navigation.

In the present invention, motion constraints refer to restrictions on the degrees of freedom that a system naturally has, and in this case, the difference between the natural degrees of freedom and the actual degrees of freedom assuming that there is nothing that restricts the motion is the constraint. It is the number of dimensions. In the present invention, the difference between the setting value of the load setting device and the fluid force on a stationary or moving model is determined, and the model is servo-driven by a servo system so as to reduce this difference to zero, and the model is set to the above setting value. A motion constraint that causes a model to move (movement with a predetermined degree of freedom) so that a force equilibrium state in which a force equal to the force is applied is created.

Waves are constantly acting on vessels, offshore structures, and other objects operating or moored at sea.
It is necessary to regulate the movement of such ships so that they can remain in operation or at anchor. The present invention relates to a motion restraint device using a servo system for a model of a ship, etc., for analyzing the motion of the ship, etc. in a stationary state and a running state in such a case.

(Prior Art) In the technical field mentioned at the beginning, it is known to conduct a test using a model of a ship or the like in order to measure the force acting on the ship or the like. Forces F X , _F Y , F _Z in the X, _Y , and Z three-axis directions and rotational moments M〓 _X , M〓 _Y , and M〓 _Z about each axis can act on the model in the fluid. Considering the motion of the ship's body, the forces in the surge direction X, sway direction Y, and yaw direction θ _Z are particularly important objects to be measured. Weights were used to measure the forces acting on models such as ship hulls (hereinafter referred to as "hydrodynamic forces"). A known method involves connecting a carriage to a model in a fluid, connecting the carriage to a towing vehicle or a towing boat with a spring, and measuring the fluid force when the carriage moves under the influence of the fluid force using a weight or a torque motor. (Japanese Unexamined Patent Publication No. 100731/1983). Such known methods merely measure the fluid force acting on the model, and are intended to measure the fluid force acting on the model and then actively cause the model to perform a desired movement based on this. do not have.

(Problem to be solved by the invention) The problem to be solved by the present invention is to measure the fluid force acting on a model of a ship, etc. in a stationary state and a running state, and furthermore, when this fluid force fluctuates from a set value, the model is immediately applied to the above set value. A motion restraint device that actively moves a model to create a force equilibrium state in which a force equal to The objective is to create a new system, and at that time, the objective is to prevent errors from occurring in the measurement of fluid force and the operation by the servo system.

(Means for Solving the Problems) The problems of the present invention are solved by the structure described in claim 1.

The invention will be explained in more detail with reference to the illustrated embodiments.

(Embodiment) Prior to describing the embodiment of the present invention shown in FIGS. 1a, 1b, and 2, the prior art will be briefly described.

FIG. 3 shows a prior art device for measuring fluid forces acting on a model of a ship or the like. Model 1 includes five directions Y, excluding the surge direction X, in the fluid.
Movements in Z, θ _X , θ _Y , and θ _Z are allowed. Each movement is independently measured using a potentiometer or the like. A rod 2 is installed upright on the model 1, and a carriage 3 that can move in the sway direction Y allows the rod 2 to measure the force in the yaw direction _θZ , but it is necessary to balance the force with the set value. control is not possible, but movement in the Z direction is possible.

The sway carriage 3 is guided on the surge carriage 4 so as to be movable transversely to the surge carriage 4 in the Y direction. Pulley units 5, 5' are attached to both ends of the surge carriage 4, and wires 6, 6' each having one end fixed to the sway carriage 3 are guided through the pulley units 5, 5'.
Correction weights 7, 7' can be attached to and removed from the tips of the wires 6, 6'.

Also, springs 8 and 8' are provided between both ends of the surge carriage 4 and the sway carriage 3, respectively.
is hung. Further, a probe 9 is attached to the joint between the rod 2 and the model 1. The probe is used to measure rolling θ _Z and pitching θ _Y. In the area between the model 1 of the rod 2 and the surge carriage 4, springs 10, 10' are attached for measuring the yaw movement _θZ . A device is also provided between the sway carriage 3 and the rod 2 for measuring the heave movement and for restricting the movement using a servo system.

In the above device, it is assumed that the model 1 is towed in the X direction and waves are acting from the direction of the arrow A. In this case, the motion and force of the model 1 are measured independently in each of the five directions, and the motion in any of the five directions can be restrained by the servo system as necessary. When the wave A acts on the model 1, the springs 8 and 8' expand and contract due to the movement of the model 1 in the sway direction Y, and the midpoint of the movement, that is, the sway carriage 3, shifts downstream of the wave A. As a result, the amount of displacement is measured using a potentiometer or the like, and the fluid force is determined by multiplying this by the spring constant of the springs 8, 8'.

After that, the springs 8, 8' are removed and the correction weights 7, 7' are loaded so that the midpoint of the movement, that is, the sway carriage 3, always returns to its original position with respect to the frame (not shown), and the force is balanced. The force directly involved in the movement can be determined from the weight of the weight.

A motion restraint device according to the present invention is shown in FIGS. 1a and 1b.
It is described in FIG. According to the illustrated device, forces F _X , F _Y in surge direction X and sway direction Y
It is also possible to measure the moment M _OZ in the yaw direction θ _Z , and based on this, it is possible to calculate the motion (acting on the model) of a model such as a ship body (not shown) whose degrees of freedom are restricted (constrained) to a predetermined number. force becomes a predetermined value). A sway carriage 22 and a surge carriage 23 are attached to the frame 21.
is installed. Sway Carriage 22 is X
It is guided on the frame 21 so as to be movable in the Y direction on a surge carriage 23 that is movable in the Y direction. A servo motor 24 is used to drive the sway carriage 22, and a surge carriage 23 is used to drive the sway carriage 22.
A servo motor 25 is disposed on each frame 21 for driving the servo motors 25 . Since the motion in the yaw direction θ _Z is a motion whose degrees of freedom are limited to a predetermined number (the force acting on the model is a predetermined value), a servo motor is attached to the rod 37, which will be explained later. be able to. Endless wires 26, 26' are wound around a pulley 25a of the servo motor 25, and wires 26, 26' are wound around two pulleys 27, 27' on the frame 21. This pulley 2
Another endless wire 29 is wound between 7 and a pulley 28 at the other end of the frame 21, and a portion of the endless wire 29 is fixed to the surge carriage 23.
Another endless wire 29' is wound between a pulley 27' and a pulley 28' fixed on the frame 21. A portion of this wire 29' is also fixed to the surge carriage 23. As a result, the motor pulley 25a is rotated by the rotation of the servo motor 25.
The surge carriage 23 can move forward and backward in the X direction on the frame 21 via endless wires 29, 29'. The wire 29' is also in transmission engagement with a surge potentiometer 30 on the frame 21. As a result, the surge potentiometer 30 is rotated when the wire 29' travels in the X direction, and the amount of movement of the wire 29' and hence the surge carriage 23 in the X direction is measured in accordance with the rotation angle.

On the other hand, another wire 31 is wound around a pulley 24a of another servo motor 24 on the frame 21. A sway potentiometer 32 disposed on the frame 21 is operatively connected to this wire 31. In the upper region of the figure, this wire 31 is wound around a pulley 33 on the frame 21, a pulley 34 on the surge carriage 23, a pulley 35 on the sway carriage 22, and then again around a pulley 33 on the sway carriage 22.
4 and is fixed to the frame 21 at the left end of the figure. In the lower region of the figure, the same wire 31 passes through a pulley 33' fixed to the frame 21, a pulley 34' on the surge carriage 23, a pulley 35' on the sway carriage 22, and then again via a pulley 34'. is fixed to the frame 21 at the left end.

A heave potentiometer 36 is fixed to the sway carriage 22, and is used to measure the displacement of the rod 37 in the Z direction, which will be explained later.

In FIG. 1b, rod 37 passes through sway carriage 22. In FIG. The rod 37 is rotatably guided relative to the sway carriage 22 and movably in the Z direction. A servo motor may be attached to the sway carriage 22 in order to move the model so that a force equilibrium state is created in which a force equal to the above-mentioned set value is applied to the model with respect to the yaw movement θ _Z of the rod 37. A load cell 38 as a multi-force detector is attached to the lower part of the rod 37. The load cell is a three-component force. It is also possible to use a load cell with three-component force to six-component force. The torsion bar 40 passes through the load cell 38 and the screw 39
It is fixed to the load cell 38 by. A model of a ship or the like (not shown) is fixed to the drive end of the load cell 38 . When using a servo motor to move the model so that a force equal to the above setting value is applied to the model in response to the rotational movement θ _Z of the rod 37 mentioned above, the moment M in the yaw direction is 〓 This torsion bar 40 for measuring _Z
becomes unnecessary. The yaw movement of the model is restrained by a servo motor. In the lower range of the load cell 38, a potentiometer 41 for yaw movement of the load cell 38, a potentiometer 43 for pitching
are respectively attached to the rod 37 for measuring the rotation angle _θZ . When _the load cell 38 is a three _- component force, each force _F By servo-driving the model with a motor, the model is moved so that a force equilibrium state is created in which a force equal to the above-mentioned set value is applied to the model, that is, the model is restrained by servo-driving in three directions. Errors in the servo system can then be eliminated.

In FIGS. 1a and 1b, the servo motor 24,
A wire pulley is used as a transmission device to transmit 25 servo drive forces to each carriage. However, other known transmission means such as belts,
Means using chains, gears, screws, hydraulic motors, and cylinders are also employed.

The servo system according to the present invention is represented by a block diagram as shown in FIG. A preamplifier 51 is connected to the load cell 38, and a main amplifier is connected to this. The main amplifier 52 is connected to a digital display 53 and at the same time to a subtracter 54. The output side of the load setting device 55 is connected to the subtractor 54 . The output side of the subtracter 54 is connected via a servo amplifier 56 to servo motors for forces X, Y, and θ _Z in three directions. The load cell 38 may have three or more components, and a corresponding number of servo motors may be provided to move the model so that a force equilibrium state in which a force equal to the above set value acts on the model is created. The servo drive by the servo motor is performed every time the force is measured at each moment, so that the force indicated by the load cell 38 immediately converges to the load setting value each time. The setting value of the setting device 55 can be a constant value or a variable value corresponding to a case where, for example, a ship's hull is accelerated with a predetermined acceleration characteristic after the start of operation. The model can be moved so that a force equilibrium state in which a force equal to the above-mentioned set value is applied to the model is generated by feedback control for the purpose of force balance using the servo motor according to the present invention between the models.

The motion restraint device of the present invention operates as follows.

A predetermined load is set in a load setting device 55 for the model, which is not shown in FIG. Load cell 3
A fluid force acts on the digital display 5.
3. A subtractor 54 performs a subtraction between the actual fluid force and the set value, and the difference forms a difference signal which is input to each servo motor. Thereby the carriage 22,2
3. The rod 37 is servo-driven or servo-rotated until the force measured by the load cell becomes equal to the set value of the load setter 55. In this way, the force indicated by the load cell 38 is always displayed on the digital display 5.
3, the servo system is driven until the force indicated by the load cell is equal to the set value.

The operation of such a servo system with the device according to FIGS. 1a and 1b takes place as follows. The servo motor 25 is rotated according to the set value of the load setting device 55, and the pulleys 27, 27',
Wires 26, 26', 2 wrapped around 28, 28'
A movement in the X direction is applied to the surge carriage 23 via 9, 29'. On the other hand, the other wire 31 is wound around pulleys 33, 33', 34, 34', 35, 35', and these pulleys rotate.
Wires 31 from the fixed ends of the upper and lower ranges
Since the lengths of each do not change, the sway carriage 2
2 movement does not occur. At this time, when a fluid force acts in the sway direction Y, the sway carriage 22 is moved by the servo motor 24 in the direction where the fluid force F _Y is equal to the set value based on the servo system shown in FIG. 2, and the force is balanced. is achieved. At this time, the fluid force F _Y is displayed on the digital display 53. The displacement θ _Z in the yaw direction is also measured by the potentiometer 41, and the rod 37 is moved by the servo motor to move the model so that a force equilibrium state in which a force equal to the above set value is applied to the model is generated, and the load cell is activated. The servo is rotated until the fluid force measured at 38 becomes equal to the set load indicated by the load setter 55. Since this is a motion restraint that moves the model so that a force equilibrium state in which a force equal to the above set value acts on the model occurs, unlike a motion restraint mode that is limited only to force balance by a spring, it is possible to Motion constraints are also made at the same time as the measurement of the fluid force. Of course, if the set value is set to zero, the moment M〓 _Z in the yaw direction θ _Z will also be zero.

(Effects of the Invention) As described above, according to the present invention, the fluid force is measured each time and displayed on the digital display, and the model is designed so that a force equilibrium in which a force equal to the set value is immediately applied to the load cell occurs. and this movement is recorded. The present invention does not stop at simply measuring the fluid force acting on the model, as is known in the art. Additionally, unlike force measurements that use weights or torque motors, fluid force can be measured accurately. This allows the movement of the model subjected to the fluid force to be recorded in accordance with the load setting conditions. Through model motion analysis according to the present invention, basic data essential for designing ships and the like can be obtained.

[Brief explanation of drawings]

Fig. 1a is a plan view of the motion restraint device for a model such as a ship in a fluid according to the present invention, Fig. 1b is a side view, Fig. 2 is a block diagram of the servo system, and Fig. 3 is a model motion restraint according to the prior art. It is a figure showing an apparatus. Codes in the figure: 21...Frame, 22...Sway carriage, 23...Surge carriage, 2
4, 25... Servo motor, 37... Rod, 3
8...multiple force detector (load cell), 55...load setting device, X...movement direction of surge carriage,
Y...Direction of movement of the sway carriage, θ _Z ...Z
Direction of motion around an axis.

Claims (1)

[Claims] 1. Motion of a model such as a ship in a fluid is controlled by at least one of the fluid forces in six directions (F _X , F _Y , F _Z , M〓 _X , M〓 _Y , M〓 _Z Measure the above force and find the difference with the load set value set on the load setting device, form a difference signal from this difference, input this to the servo system, and make the difference with the above set value zero. In a motion restraint device for a model such as a ship, model 1 is used to servo-drive the model using a servo system and move the model so that a force equilibrium state in which a force equal to the above-mentioned set value is applied to the model is created. A multi-force detector 38 mounted on a rod movably supported relative to the frame 21 and coupled to the model 1 for measurement of at least one of the fluid forces in six directions, and 1, a device 54 for calculating the difference between the set load value of the load setting device and the fluid force measured by the multi-force detector 38; A motion restraint device for a model such as a ship, comprising an amplifier 56 that forms an input signal, and a servo system that receives a difference signal and servo-drives the model 1 so as to make the difference zero. 2 Guide the surge carriage 23 to the frame 21 so that it can move in one direction
A sway carriage 22 is guided so as to be movable upward in a direction Y perpendicular to the direction A rod 37 passes through the rod, and another servo motor is attached to the rod, which enables the model to be servo driven in the yaw direction (θ _Z ). The models are connected, and the model is servo-driven by a servo system so that a force equilibrium state is created in which a force equal to the set load value set in the load setting device 55 is applied to the model to which fluid force is applied. A motion restraint device for a model of a ship, etc., as set forth in claim 1. 3. The motion restraint device for a model of a ship or the like according to claim 1 or 2, wherein a torsion cover 40 is used to measure displacement in the yaw direction (θ _Z ).