JP4290665B2 - Crane motion control device - Google Patents

Description

  The present invention relates to an operation control device for a crane. More particularly, the present invention relates to an operation control device that rotates a drive motor by a rotation speed controller such as an inverter to perform operations such as traveling and turning of a crane.

In a traveling device using an inverter which is an example of a rotational speed controller, a speed signal is output to a motor by the inverter, and acceleration / deceleration is performed toward an instructed speed. In this case, when the speed signal value changes, acceleration / deceleration is performed from the current speed toward the new command speed at a constant acceleration / deceleration. Therefore, when the traveling of the crane is stopped at a predetermined stop position, the stop position will be shifted unless the driver's command timing is performed fairly accurately.
By the way, in a crane capable of turning, it is necessary to have a technique that is more difficult than traveling to turn the suspended load to a predetermined position after turning the suspended load. This is because the swinging movement of the swing crane has a high moving speed of the suspended load and it is difficult to stop the swing of the suspended load.
In other words, when there is a constant turning deceleration, the deceleration start timing must be selected within a very narrow time period in order to prevent the load from swinging after stopping. In order to achieve the above, skilled and sophisticated operation is required.

Thus, in addition to the inverter control described above, a device using a mechanical brake has been developed.
Conventional example 1 (Patent Document 1)
In addition to the induction motor driven by the inverter, it is equipped with a mechanical brake that can be operated arbitrarily by the driver. When the mechanical brake is used to decelerate, the output frequency of the inverter is synchronized with the traveling speed, and the mechanical brake The brakes are stopped and the interference between the braking of the motor and the driving torque of the motor is eliminated.
Conventional example 2 (Patent Document 2)
In a crane traveling device that includes a brake that applies a mechanical control force to the output of a crane traveling motor, and that controls the speed of the crane traveling motor by controlling an inverter based on a speed command output from an acceleration / deceleration calculator. As a configuration in which the value based on the speed detected by the speed detection means is input to the deceleration calculator, the brake is operated with the inverter and crane traveling motor electrically connected during coasting operation of the crane traveling motor. The crane traveling motor is decelerated, and when the crane traveling motor is reaccelerated or reversely rotated, the speed value based on the number of revolutions of the crane traveling motor detected by the speed detecting means is set as the crane traveling speed command. The inverter is controlled based on the speed command output from the acceleration / deceleration calculator.
Conventional example 3 (Patent Document 3)
In order to increase the responsiveness that can be suddenly accelerated and reversed as desired by the operator, speed detection means are provided, and the inverter is controlled with vector control with speed sensor, sensorless vector control, speed detection means by speed estimation calculation. To do. At the time of coasting, the maximum torque of the motor is limited and brakes are applied in the power-on state, and after the coasting operation, the target speed command is set at the time of reacceleration or reverse rotation, and then the operation is performed with a torque limit that can be changed.

  Conventional Examples 1 to 3 all use a mechanical brake, but it is difficult to match the mechanical brake and the inverter, and contrivances are made such as using complicated control to avoid interference. Still, it was the cause of motor and inverter failure.

JP-A-7-61769 Japanese Patent No. 3362830 JP-A-11-268885

  In view of the above circumstances, the present invention provides a crane operation control device that can continuously change the deceleration over a wide range at the time of deceleration without causing failure of the motor or inverter, and that can easily realize positioning and steadying with ease. For the purpose.

In the crane motion control apparatus according to the first aspect of the present invention, the rotation speed controller outputs a rotation speed signal based on the direction / speed control signal from the arithmetic control apparatus, and the drive motor is rotated by the rotation speed signal to operate the crane. The crane includes a main operation means for manually giving a direction / speed command to the arithmetic control device, and a sub operation means for giving a deceleration command by a stepping operation. The arithmetic control device includes: A normal operation is performed based on the direction / speed command, and a forced deceleration operation is performed when there is a stepping operation of the sub-operating means. When the forced deceleration operation is performed, a forced deceleration signal is output and a stepping operation amount Is sent to the rotation speed controller.
The crane motion control apparatus according to a second aspect of the present invention is the operation control apparatus according to the first aspect, wherein the arithmetic control unit includes a speed set value calculator and an acceleration / deceleration calculator for normal operation, a forced deceleration command unit for forced deceleration operation, A deceleration calculator, and the speed setting value calculator sends a zero-speed signal to the acceleration / deceleration calculator based on a forced deceleration command from the forced deceleration commander. The acceleration / deceleration calculator outputs a deceleration signal to the rotation speed controller based on a deceleration command from the deceleration calculator.
The crane motion control apparatus according to a third aspect of the present invention is characterized in that, in the first aspect, a change amount d of a deceleration command issued by the deceleration calculator is obtained by the following equation (1).
d = {(p−P1) / (P2−P1)} × (D2−D1) + D1 (1)
Sub operation amount of stepping operation: p
Depression operation amount for starting forced deceleration control: P1
Maximum operation amount of sub-operation means: P2
Speed command change amount per scan at the longest deceleration time: D1
Speed command change amount per scan at minimum deceleration time: D2

According to the first aspect of the invention, when the sub-operating means is stepped on, it is switched to the forced deceleration operation to decelerate in preference to the normal operation, so that no interference occurs between the rotation speed controller and the drive motor. . Further, since the deceleration is proportional to the amount of depression of the sub-operating means, the deceleration can be freely changed to accurately position the stop position and suppress the swing of the suspended load.
According to the second invention, the speed set value calculator and the acceleration / deceleration calculator for normal operation, the forced deceleration command unit and the deceleration calculator for forced deceleration operation are provided as separate systems, and the sub-operation When there is a stepping operation, the control signal is sent via the speed setting value calculator and the acceleration / deceleration calculator for normal operation according to the forced deceleration command of the forced deceleration commander and the deceleration command of the deceleration calculator. Since it is sent to the speed controller, there is no interference inside the control system, and the control signal to the speed controller is limited to one system, so that the forced deceleration of the crane can be performed reliably and smoothly.
According to the third invention, the deceleration command issued by the deceleration calculator changes so as to be proportional to the depression amount of the sub-operating means. Therefore, the operation approximated to controlling the pressure of the hydraulic brake by the depression amount. Therefore, the driver can easily perform the deceleration operation, and can accurately stop at the stop position without requiring skill, and can prevent the swinging of the load.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of an operation control device for a crane according to an embodiment of the present invention, FIG. 2 is a functional explanatory diagram of an arithmetic control device, and FIG. 3 is a time chart for explaining deceleration control.

First, the outline of the crane motion control apparatus will be described with reference to FIG.
The manual lever 1 is an example of the main operating means referred to in the claims. This main operation means may be constituted by known manual operation means such as buttons and dials in addition to the lever. The driver can give a direction command and a speed command for normal driving by the manual lever 1.
The foot pedal 2 is an example of the sub operation means referred to in the claims. In addition to the pedal, the sub operation means may be a known step operation means such as a foot lever. The driver can command forced deceleration and deceleration by depressing the foot pedal 2 when he / she wants to decelerate. The presence / absence of the stepping pedal 2 and the amount of depression may be detected by a potentiometer or the like connected to the pedal.

The arithmetic and control unit 3 is constituted by a known computer or the like, and has a function of sending a direction / speed control signal to a rotational speed controller 4 to be described later while adjusting the acceleration / deceleration by input from the manual lever 1 and the foot pedal 2 .
The rotation speed controller 4 is constituted by a known inverter, for example. The rotation speed controller 4 controls the rotation of the drive motor 5 by outputting a rotation speed signal based on the speed / direction control signal from the arithmetic and control unit 3. When an inverter is used as the rotational speed controller 4, the induction motor 5 is used as the drive motor 5, for example, and the rotational speed control is performed by varying the frequency and voltage.
In the crane to which the present invention is applied, instead of the inverter and the induction motor, the thyristor may be a rotational speed controller and the DC motor may be a drive motor.

Details of the arithmetic and control unit 3 will be described with reference to FIG.
The arithmetic and control unit 3 includes a speed setting value calculator 31 and an acceleration / deceleration calculator 32 for normal operation, and a forced deceleration commander 33 and a deceleration calculator 34 for forced deceleration.
The speed setting value calculator 31 for normal operation has a function of setting a target speed, and receives an instruction from the manual lever 1 and sets it. From the manual lever 1, direction commands “F” and “R” and speed commands 1 to 4 notches (in the illustrated embodiment, there are four stages from 1 notch to 4 notches) according to the lever operation amount. Is output. When the manual lever 1 is neutral, 0 speed is set.
The acceleration / deceleration calculator 32 has a function of calculating an acceleration / deceleration for reaching the target speed. In response to an acceleration command and a deceleration command associated with the notch change of the manual lever 1, an acceleration / deceleration acceleration command and a deceleration command are output. The acceleration and deceleration in this case are set to change at a constant rate.
The inverter 4 and the motor 5 that perform the rotational speed control in accordance with the operation direction command calculation method and the control signal output from the acceleration / deceleration calculator 32 are exactly the same as in the conventional control.

  The forced deceleration command device 33 for forced deceleration has a function of issuing a forced deceleration command to the speed set value calculator 31 when detecting that the stepping on the foot pedal 2 has exceeded the allowance. The deceleration calculator 34 has a function of calculating a deceleration according to the depression amount of the foot pedal 2 and outputting it to the acceleration / deceleration calculator 32.

The deceleration setting method in the deceleration calculator 34 of this embodiment is as shown in the following formula (1).
d = {(p−P1) / (P2−P1)} × (D2−D1) + D1 (1)
Foot pedal operation amount: p
Deceleration control start foot pedal operation amount: P1
Maximum pedal operation amount: P2
Speed command change amount per scan at the longest deceleration time: D1
Speed command change amount per scan at minimum deceleration time: D2
Change amount of speed command according to the operation amount of the foot pedal: d
As shown in the above equation (1), the deceleration calculator 34 operates the foot pedal 2 so that when a forced deceleration command is issued, the deceleration command of the acceleration / deceleration calculator 32 is subtracted by d per scan. ing. A speed control signal that changes in response to the deceleration command is output from the acceleration / deceleration calculator 32 to the rotation speed controller 4. Further, the deceleration control corresponding to the pedal depression amount is continued until the drive motor 5 is finally stopped.
By performing such control, when the driver operates the foot pedal 2, it is possible to obtain an operability approximate to that when the pressure of the hydraulic brake is controlled by the depression amount.

Next, the control operation of the operation control device will be described.
(Normal operation mode)
The speed set value calculator 31 performs the following normal operation control by the direction command (F ′, R ′) and the speed command (1 to 4) from the manual lever 1.
a) If the direction command to the manual lever 1 and the rotational speed controller (inverter) 4 is the same, or the speed command to the rotational speed controller (inverter) 4 is 0 speed, set the speed to the manual lever. A speed command is output corresponding to one notch (1 to 4).
b) When the direction commands to the manual lever 1 and the rotation speed controller (inverter) 4 do not match, the speed setting outputs a 0 speed command.
c) When the set speed is greater than the rotation speed controller (inverter) command speed, the amount of change for one scan is determined by the rotation speed controller (inverter) according to the acceleration command per scan (refers to a one-step calculation with a programmable controller or the like). ) In addition to the speed command, the speed command of the rotation speed controller (inverter) is changed by a ramp function.
d) When the set speed is smaller than the rotation speed controller (inverter) command speed, the amount of change for one scan is set to the rotation speed controller (in accordance with the deceleration command per scan (refers to one-step calculation with a programmable controller or the like)). Inverter) Subtract from the speed command to change the speed command of the rotation speed controller (inverter) with a ramp function.

(Forced deceleration mode)
The forced deceleration mode is executed with priority over the normal operation mode. That is, when the foot pedal 2 is depressed beyond the allowance, a forced deceleration command is issued, and the target speed setting is unconditionally set to 0 speed. That is, the forced deceleration command is sent to the speed set value calculator 31. Then, deceleration control from the current speed to 0 speed is performed by the deceleration calculator 34 outputting a deceleration command to the acceleration / deceleration calculator 32.
As described above, the deceleration command output by the deceleration calculator 34 increases or decreases the deceleration according to the amount of depression of the foot pedal 2 as in the above equation (1). An operability approximate to that of controlling the pressure by the amount of depression can be obtained. For this reason, it can be operated so as to stop the crane operation (running or turning).

Based on FIG. 3, the driving | running state of the control action including a forced deceleration is demonstrated.
First, when the manual lever 1 is operated with 4 notches, the speed command is operated with a speed setting value (maximum speed) of 4 notches. This state is a normal operation mode.
In this state, when the foot pedal 2 is depressed and the play allowance of the foot pedal 2 is exceeded (point of T1), the speed set value is forcibly set to zero. The initial deceleration command value starts decelerating at the longest deceleration gradient.
When the foot pedal 2 is further depressed, the mode is switched to the forced deceleration mode. In this mode, the deceleration increases in proportion to the depression amount (T1 → T2), and the deceleration decreases when the depression amount is returned (T2 → T3).
When the amount of depression becomes further smaller than the allowance for the foot pedal 2 (point of T3), the speed setting value becomes a speed setting value of 4 notches, and acceleration is performed according to the set acceleration. In this way, it is possible to obtain operability that is similar to that of controlling the pressure of the hydraulic brake by the depression amount by operating the foot pedal.
After this, returning to normal operation and operating the manual lever 1 to 2 notches during acceleration (point of T4), the speed setting value becomes 2 notch speed, and acceleration or setting by the set acceleration (acceleration command) (Acceleration or deceleration is determined by the speed command to the inverter when operating to 2 notches and the magnitude of the 2 notch setting speed) according to the deceleration (deceleration command 1) being performed, the speed is constant when the speed becomes 2 notches Drive on.
Then, when the notch is returned to 0 notch (point of T5), the speed set value becomes 0, decelerates at the set deceleration, and stops.

  The above speed control can be applied to both traveling and turning of the crane. In particular, when applied to turning, since the deceleration before the turning end point can be performed delicately, the operator can accurately position and stop without swinging the swing load without requiring skill.

It is a block diagram of an operation control device concerning one embodiment of the present invention. It is function explanatory drawing of a calculation control apparatus. It is a time chart explaining deceleration control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manual lever 2 Foot pedal 3 Arithmetic controller 4 Rotational speed controller 5 Drive motor 31 Speed set value calculator 32 Acceleration / deceleration calculator 33 Forced deceleration command device 34 Deceleration calculator

Claims (3)

In the crane that the rotation speed controller outputs the rotation speed signal based on the direction / speed control signal from the arithmetic control device, and the crane is operated by rotating the drive motor by the rotation speed signal.
For the arithmetic and control unit, a main operation means for giving a direction / speed command by manual operation and a sub-operation means for giving a deceleration command by a stepping operation are provided,
The arithmetic and control unit performs a normal operation based on a direction / speed command from the main operation means, and performs a forced deceleration operation when a stepping operation is performed on the sub operation means, and performs the forced deceleration operation. Outputs a forced deceleration signal and sends a deceleration signal proportional to the stepping operation amount to the rotational speed controller. The arithmetic and control unit includes a speed set value calculator and an acceleration / deceleration calculator for normal operation, a forced deceleration command unit and a deceleration calculator for forced deceleration operation,
Based on the forced deceleration command from the forced deceleration command device, the speed set value calculator outputs a 0 speed signal to the acceleration / deceleration calculator.
2. The crane operation control according to claim 1, wherein the acceleration / deceleration calculator is executed by outputting a deceleration signal to the rotation speed controller based on a deceleration command from the deceleration calculator. apparatus. The change amount d of the deceleration command issued by the deceleration calculator is obtained by the following equation (1): d = {(p−P1) / (P2−P1)} × (D2−D1) + D1 (1)
Sub operation amount of stepping operation: p
Depression operation amount for starting forced deceleration control: P1
Maximum operation amount of sub-operation means: P2
Speed command change amount per scan at the longest deceleration time: D1
Speed command change amount per scan at minimum deceleration time: D2
The crane motion control apparatus according to claim 1.

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