JPH0227491B2 - SHUNSETSUFUNENOKUTSUSAKUSEIGYOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an excavation control device for a dredger that excavates earth and sand from the bottom of a water body.

When increasing the water depth of a channel or anchorage, or excavating a foundation for the construction of an underwater structure, the earth and sand at the bottom of the water are excavated, the excavated earth and sand is pumped up and sent to land through a drainage pipe. Drilling boats are used. Fig. 1 is a plan view showing the outline of such a dredger, and Fig. 2 is a side view thereof.
In these figures, 1 is the hull. A rudder 2 is attached to the tip of the hull 1 and rotates in the elevation direction about a horizontal pin 2a, and a cutter 3 is provided at the tip of the rudder 2. This ladder 2 is
Drum 2 driven at constant speed by AC motor 2b
It is raised and lowered by a ladder wire 2d that is wound or fed out by a wire 2c, and the amount of the rise and fall is detected by a rotary encoder 2e connected to a horizontal pin 2a. The cutter 3 is used to rotatably excavate earth and sand at the bottom of the water. Next, 4 is
It is a rod-shaped spud that extends from the hull 1 to the bottom of the water.
It is provided at the rear of the hull 1 and serves as a fulcrum when the hull 1 swings. Moreover, 5a and 5b are anchors fixed to the bottom of the water, and each is connected to swing wires 6a and 6b. 7a, 7b
is a sheave (pulley) provided on the rudder 2, so that the swing wire 6a is wound onto the winch drum 8a via the sheave 7a, and the swing wire 6b is wound onto the winch drum 8b via the sheave 7b. It's summery. DCM1 is a DC motor that drives the winch drum 8b via the reducer 9b, and DCM2 is a DC motor that drives the winch drum 8a via the reducer 9a.

When the above-mentioned dredger is to be swung to the right from point B to point A, for example, the winch drum 8a is rotated while applying a regenerative brake to the DC motor DCM1 and applying an appropriate tension to the swing wire 6b.
The swing wire 6a is wound up and rotated to point A. At the same time, the cutter 3 is used to excavate the bottom of the water for dredging. Then, when the right swing is completed, excavation in the depth direction is performed next. That is, while stopping the DC motor DCM1 on the anti-swing side (left side) and applying a mechanical brake, the amount of torque of the DC motor DCM2 on the swing side is adjusted to prevent the rudder 2 from shifting in the left-right direction, and the rudder wire 2d is After loosening, the cutter 3 is used to excavate in the depth direction. Then, when a predetermined depth is reached, a left swing is performed. In this way, by repeating left and right swings, when the amount of excavation reaches the desired depth, move the position of the spud 4 forward and continue digging by repeating left and right swings in the same manner as above, to cover the entire target area. Perform drying.

FIG. 3 is a block diagram of a conventional excavation control device for controlling the above-mentioned excavation operation, and in this figure, parts corresponding to those in FIGS. 1 and 2 are given the same reference numerals.

In this figure, SW1 is a switch that is turned ON when the motor swings to the left, and a speed signal _S1 that commands the rotational speed of the DC motor DCM1 is supplied as an addition signal to the deviation detection point _a1 via this switch SW1. In addition, a DC motor DCM is installed at the deviation detection point _a1 .
The output signal of the indicator generator PG, which outputs a voltage corresponding to the rotation speed of 1, is supplied as a subtraction signal, and the deviation obtained at this deviation detection point a ₁ is sent to the controller.
Supplied to CL ₁ . The controller CL ₁ controls the DC motor DCM based on the deviation obtained at the deviation detection point a ₁
Outputs a signal Sa that commands an armature current value of 1.
In this case, the signal Sa output by the controller CL ₁ is a signal that makes the deviation at the deviation detection point a ₁ zero. _SW2 is a switch that contacts contact L when swinging to the left and contact R when swinging right, and its common terminal is connected to deviation detection point _a2 . Deviation detection point a ₂
The feedback value Iaf of the armature current supplied from the current transformer CT is supplied as a subtraction signal, and the signal Sa is used as an addition signal during left swing, and the armature current set by variable resistor VL ₁ during right swing. A command value SIa (constant value) is supplied as an addition signal. The controller CL ₂ calculates the firing angle of the forward converter CH, which can be switched between forward and reverse, based on the deviation obtained at the deviation detection point a ₂ , and sends the firing angle signal S _G obtained as a result to the gate pulse generator GPG.
This is a controller that supplies data to 1. The gate pulse generator GPG1 is a forward converter based on the firing angle signal S _G
Supply ignition pulse GP to CH. AC ₁ is the power supply for the armature circuit of the DC motor DCM1. _F1 is a field winding of the DC motor DCM1, and current is supplied from the power supply _AC2 via the thyristor 15. Note that the common line of the field winding circuit is not shown. a ₃ is the deviation detection point, and the field weakening reference signal
Ds is supplied as an addition signal, and armature voltage feedback signal Va is supplied as a subtraction signal. The controller CL ₃ uses a gate pulse generator to generate a firing angle signal that reduces the field current to protect the motor when the deviation obtained at the deviation detection point a ₃ becomes negative, that is, when Va≧Ds. Supply to GPG2,
In other cases (when Va<Ds), the firing angle signal that keeps the field current constant is sent to the gate pulse generator GPG.
Supply to 2. The left swing control circuit LS is configured by each of the above-mentioned components. Further, a right swing control circuit RS is configured in the same manner as the left swing control circuit LS. To describe the correspondence of the main components of the left swing control circuit LS and the right swing control circuit RS, controllers CL ₁ to _{CL 3} correspond to controllers CR ₁ to _{CR 3} , respectively, and deviation detection points a ₁ to a ₃ correspond to The deviation detection points b ₁ to b ₃ correspond to each other, and the switch SW ₂ , the variable resistor VL ₁ , and the thyristor 15 correspond to the switch SW ₄ , the variable resistor VL ₂ , and the thyristor 16, respectively. Further, _F2 is a field winding of the DC motor DCM2, and _SW3 is a switch that is turned on when swinging to the right.

Next, the operation of the conventional excavation control device described above will be explained.

First, when swinging to the right, switch SW ₁ is off.
SW ₃ is turned on, and switches SW ₂ and SW ₄ are both connected to the L side. As a result, the DC motor DCM
2 rotates based on the speed signal _S1 , and the swing wire 6a is wound around the winch drum 8a. On the other hand, the armature current of the DC motor DCM1 is controlled to a constant value set by the variable resistor VL ₁ , and therefore the DC motor DCM1 responds to the difference between its output torque and the tension of the swing wire 6b. (usually rotates in the opposite direction) and applies regenerative braking in the swing direction (right side). In this way, the excavation control device swings to the right while applying braking on the port side of the hull 1 (FIG. 1).

When the right swing is completed in this way, the rudder descent control is performed next. Figure 4 is an explanatory diagram of the _same .
Although not shown, it is located towards the front of the figure. and,
While the cutter 3 (therefore, the rudder 2) is maintained within the range of the left set value x _L and the right set value x _R , the ladder wire 2 d shown in FIG. It will be done. At this time, in conventional ladder lowering control, the DC motor DCM1 on the anti-swing side (in this case, the left side) is turned off, a mechanical brake is applied to the winch drum 8b, and the output torque of the DC motor DCM2 on the swing side (right side) is While changing the horizontal position x of rudder 2 and cutter 3
is under control. For example, in Fig. 4, when the position x of the cutter 3 exceeds the left set value x _L , the armature current Ia of the right DC motor DCM2 is increased,
Prevent it from shifting to the left, and if it is the other way around, the DC motor
Weaken the armature current Ia of DCM2 to prevent it from shifting to the right. In this case, the amount of increase in armature current Ia is determined in proportion to the deviation x- _xc from the reference position _xc .

By the way, the soil to be dredged has variations in hardness and softness, and due to this, the swing wire 6
The forces applied to a and 6b also change. That is, when the soil is hard, the cutter 3 descends while digging little by little, so the force applied to the swing wires 6a, 6b is weak.On the other hand, when the soil is soft, the cutter 3 excavates a large amount, and the force applied to the swing wires 6a, 6b is weak. The applied force becomes stronger. Therefore, the aforementioned DC motor
If the output torque of DCM2 is set to be suitable for hard soil, the pulling force to the right will be too weak when the soil is soft, and the cutter 3 will tend to shift to the left.On the contrary, it is set to be suitable for soft soil. If the soil is hard, the force pulling it to the right will be too strong and it will tend to shift to the right. Furthermore, with the conventional method of determining the increase or decrease in armature current in proportion to the deviation from the reference _position Even if it is successfully controlled, it may not be possible in soils of other hardness.

In view of the above-mentioned circumstances, this invention provides excavation control for a dredging vessel that can lower the rudder while keeping the lateral position of the cutter within a set value (within the target standard) for any soil type. This device applies a brake to the non-swing side electric motor, while increasing/decreasing the torque amount of the swing side electric motor based on the torque command value, thereby maintaining the horizontal deflection of the cutter within the set range. , in an excavation control device for a dredger that performs rudder lowering control, a timer that measures the time t from when the rudder lowering control is started until the horizontal deflection of the cutter first deviates from the set range; , where the original torque command value is Tcn _-1 and the constant is K, each time the left-right deflection of the cutter deviates from the setting range, the formula becomes Tcn=Tcn _-1 ±K/t (however, The sign ± is determined depending on whether the direction in which the cutter deviated is to the left or to the right).

Embodiments of the present invention will be described below based on the drawings.

FIG. 5 is a block diagram showing the configuration of a main part of an embodiment of the present invention. In the figure, reference numeral 31 indicates a torque command value for commanding the torque command value Tc of the swing side DC motor in the ladder lowering control. This torque command device 31 includes a timer 31a and a control section 31.
It consists of b. The timer 31a is set so that the cutter 3 first receives the set value x _L ~ x _R after the rudder descent control is started.
This is to measure the time t until the deviation occurs. Further, the control unit 31b is activated by the ladder descent start command signal S _L and starts the timer 31a. Then, the signals Sx _L and Sx _R supplied from the variable resistors VL ₄ and VL ₅ that respectively set the left set value x _L and the right dead zone x _R , and the signal Sx corresponding to the horizontal position x of the cutter 3. Based on this, it is constantly checked whether the cutter 3 deviates from the set values x _L to x _R , and the timer 31a is stopped when the cutter 3 deviates from the set values x L to x R for the first time. Further, the control unit 31b controls the cutter ₃ to set the set value _xL to Every time we deviate from _R ,
Calculate a new torque command value Tcn ₊₁ . and,
Torque command signal corresponding to this torque command value Tc
S _T is supplied to the converter 32 . In addition, the torque command value
The initial value Tco of Tc is determined to be equal to the output torque of the swing-side DC motor at the end of the swing, and is supplied to the control unit 31b as a signal S _Tco . next,
Converter 32 calculates armature current Ia of the swing-side DC motor based on torque command signal _ST , and outputs the calculation result as armature current command signal SIa.
That is, converter 32 converts torque command signal _ST into armature current command signal SIa. The torque control unit 33 is configured as described above, and in this embodiment, two sets of the torque control unit 33 are provided, and the output signal SIA of the converter 32 of one set is connected to the variable resistor VL shown in FIG. In place of the output signal of variable resistor VL ₂ , the output signal SIa of the converter 32 of the other set is supplied to terminal R of switch SW ₂ instead of the output signal of variable resistor _{VL 2 .} do.

Next, the control operation of this embodiment with the above-described configuration will be explained with reference to FIGS. 4 to 6. In the same way as in the conventional example already explained, when the right swing ends, the DC motor DCM on the anti-swing side (left side)
1 is turned off and a mechanical brake is applied to the winch drum 8b. On the other hand, the output torque of the DC motor DCM2 on the swing side is determined by the torque command value Tc by the armature current command signal SIA supplied from the torque control section 33 to the controller _CR2 via the switch _SW4 shown in FIG. It is controlled so that Here, since the torque command value Tc takes the initial value Tco at the start of the ladder descent control, the output torque of the DC motor DCM2 at this time becomes Tco.

In such a setting, when the ladder descent control is started, excavation in the depth direction by the cutter 3 is started, and a ladder descent start command signal S _L is supplied to the control section 31b. and control section 31b
starts the process shown in the flowchart of FIG. Processing at the start of rudder descent control.

When a rudder descent control command is issued, the control unit 3
1b turns off the timer measurement flag (1-bit memory provided in the control section 31b) and starts the timer 31a. This timer measurement flag is off while measuring time t.

Measurement of time t and first correction of torque command value.

When the above processing is completed, the control unit 31b sends a signal
By comparing Sx, Sx _L and Sx _R , it is constantly checked whether the position x of the cutter 3 has gone outside the set values x _L to x _R. That is, it is checked whether the position x of the cutter 3 is on the left side of the set value x _L (x<x _L ) or on the right side of the set value x _R (x>x _R ). When the cutter 3 first deviates from the set values x _L to x _R , the control section 31b immediately stops the timer 31a and turns on the timer measurement flag.
When the time t is determined in this way, the control unit 31b
A new torque command value Tc ₁ is calculated based on the initial value Tco of the torque command value Tc and the constant K using the following equation.

Tc ₁ = Tc ₀ ±K/t...(1) However, the sign + means that cutter 3 exceeds the set value x _L. The sign - means that cutter 3 exceeds the set value x _R. In other words, cutter 3 moves to the left If it deviates in the direction, the torque command value Tc is increased to pull the cutter 3 to the right, and if it deviates to the left, the torque command value Tc is weakened to return the cutter 3 to the left.

When cutter 3 deviates from the set value x _L ~ x _R more than once.

In this case, each time there is a deviation, the previous torque command value Tcn _-1 is corrected by the following formula to calculate the current torque command value Tcn. At this time, the value measured at time t is used as is.

Tcn=Tcn _-1 ±K/t...(2) However, the sign + means that cutter 3 exceeds the set value x _L. The sign - means that cutter 3 exceeds the set value x _R. The meaning of the above equation is ( This is the same as equation 1). In this way, for example, _the torque command value Tc 2 after the cutter 3 exceeds the set value x _L twice in succession becomes Tc ₂ =Tc ₀ +2K/t.
That is, K/t is added twice to the initial value Tc ₀ . In this way, every time the cutter 3 exceeds the set value x _L , K/t is added, and every time the cutter 3 exceeds the set value x _R , K/t is added.
is subtracted. In this way, the torque command value Tc is corrected based on the time t, and the correction amount becomes smaller as the time t becomes longer. After excavation to a predetermined depth, the next swing is to the left.

According to the embodiment described above, in the ladder descent control, it is possible to perform excavation in the depth direction while keeping the lateral position of the cutter within the set range, regardless of the soil quality.

This is because when the soil is hard, the cutter excavates little by little while descending, so the force applied to the swing wire is weak.On the other hand, when the soil is soft, the cutter excavates a large amount and the force applied to the swing wire becomes strong. However, since the change in the force applied to the swing wire due to such changes in soil quality corresponds precisely to the time it takes for the cutter to deviate from the set value, the output torque of the DC motor on the swing side can be adjusted based on this time. This is because, according to this embodiment, the output torque, that is, the force for pulling the swing wire, can be automatically controlled to suit both hard and soft soil types.

In the above description, the rudder lowering control at the right cut point has been described, but the rudder lowering control at the left cut point is performed in exactly the same manner.

As explained above, the present invention adjusts the output torque of the swing-side DC motor based on the time from the start of the rudder descent control until the cutter deviates from the set value, so it is possible to Unlike conventional excavation control equipment, in which the output torque of the DC motor on the swing side had to be manually adjusted based on experience, changes in the environment caused by external disturbances can be dealt with automatically, ensuring a stable rudder at all times. Descent control can be performed.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the outline of a dredge vessel, Fig. 2 is a side view thereof, Fig. 3 is a block diagram showing the configuration of a conventional excavation control device, and Fig. 4 is for explaining rudder descent control. , FIG. 5 is a block diagram showing the configuration of the main part of this embodiment, and FIG. 6 is a control section 31b.
This is a flowchart for explaining the operation. 3...Katsuta, 31a...Timer, 31b...
Control unit, DCM1, DCM2...DC motor (motor), Tc...Torque command value, x _L ~ x _R ... Setting value.

Claims (1)

[Claims] 1. While applying a brake to the non-swing side electric motor, the amount of torque of the swing side electric motor is increased or decreased based on the torque command value, thereby maintaining the horizontal swing of the cutter within the set range. , an excavation control device for a dredger that performs rudder lowering control, comprising: a timer that measures the time t from when the rudder lowering control is started until the horizontal deflection of the cutter first deviates from the set range; , When the original torque command value is Tcn _-1 and the constant is K, each time the horizontal deflection of the cutter deviates from the setting range, the formula becomes Tcn=Tcn _-1 ±K/t (however, 1. An excavation control device for a dredge vessel, characterized in that the sign ± is determined depending on whether the direction in which the cutter deviated is to the left or to the right.