JPH0570100A - Load balancer control method - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] When operating the load balancing device in a balanced state, the load can always be seated in a stable state regardless of the weight of the load and the operating speed of the lifting device. (EN) A load balancer that eliminates the displacement of the landing position and stops the suspended load without damaging or damaging the suspended load. The load balancer accurately determines seating of a suspended load by calculating a detection signal of the load detector 14 and a position signal of a load position detector 18 regardless of the weight of the load and the speed of the lifting device. And place the suspended load exactly where you want to put it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive circuit for driving an actuator and a load detector for detecting the weight of the load by elevating and lowering the load by using an actuator such as a winding type or parallelogram link type electric motor. Detecting the seating of the load in the load balancer, which has a weight storage unit that stores the weight of the load and allows the worker to raise and lower the load by handling the load using the deviation between the stored weight and the detected weight as a command. Control method.

[0002]

2. Description of the Related Art There is no load seating detection method in this type of load balancer, and there is a method of canceling the load balance state and stopping the elevating mechanism by detecting a sudden change in load weight and an applied impact. It was being done. For example, JP-A-63-
235299 (equilibrium cargo handling device) and Japanese Patent Laid-Open No. 1-3032
95 (safety circuit for balanced cargo handling equipment).

In Japanese Patent Laid-Open No. 63-235299 (balanced cargo handling device), the lifting and lowering are stopped by detecting an impact on the load and a sudden change in the load weight. This method detects the weight of the load with a load sensor, differentiates the detection value of this load sensor to obtain the rate of change of the applied force, and the magnitude of the rate of change of the force that the operator can artificially apply is the impact. By taking advantage of the fact that it is much smaller than in the above cases, it is judged whether the force applied to the load is an artificial force or a sudden change in impact / load weight, and the device is stopped.

In Japanese Patent Laid-Open No. 1-303295 (Safety circuit for balanced cargo handling device), the output of a load sensor for detecting the weight of a load is differentiated, and the differential signal and the speed detection signal of the lifting device are used to obtain a load differential signal. When the absolute value of is larger than the threshold value and the absolute value of the speed signal is larger than the threshold value, the balanced operation is stopped, and the threshold value of the load differential signal is increased in proportion to the memory load. When the load suddenly changes, the equilibrium operation is stopped, and when the weight of the load becomes large, the threshold value of the load differential signal is increased so that the sudden change of the load can be determined even if the weight of the load becomes heavy.

Further, there is JP-A-53-142750 (a suspended load landing detection method for a crane) for an automatic crane, hoist or the like which uses a motor to raise and lower a suspended load, although it is not a load balancing device. There is a method of detecting the input power of the motor driving the motor, comparing the change of the detection signal with a preset standard value, detecting the load fluctuation when the suspended load lands, and stopping the load.

[0006]

In the conventional load balancer, the method of detecting the seating of the load lifted and lowered by the lifting and lowering means is not limited to the detection of a sudden change in the load weight or an impact. If a method of detecting a sudden change in the load or stopping as a shock is given, a considerable shock will be given to the load, and if the load is weak to the shock, the load will be destroyed and the product surface will be damaged, which is desirable. Not the way.

Further, when the load is handled slowly in an equilibrium state, even if the load is seated, the detection signal from the load sensor does not change abruptly and changes only gradually, and the seating of the load is used as an operating force by the operator. Since it will detect it, the balancer will perform the balancing operation again after sitting once, so it will be a little floating from the seating point and it will not be possible to sit without releasing the balance state It becomes difficult to seat it exactly where you want to put it, and it is necessary to turn off the equilibrium motion once.

Therefore, if an attempt is made to detect this signal which changes only gradually by a conventional method, it cannot be detected by a sudden change in the load, and there is no other way than to reduce the absolute value threshold value of the load differential signal. If the load is to be detected with a small value, the load will be detected even in the case of a balanced operation by the operator, and the load will not be actually detected.

Also, in the method of detecting the change in the input power of the drive motor, when the weight of the load is light or the efficiency of the lifting mechanism is low, the detected change in the input power is small and is almost not detected as sitting. It is impossible.

As described above, in the conventional load balancing apparatus, when the load is operated in the balanced state, the load cannot always be seated in a stable state regardless of the weight of the load and the operating speed of the operator.

The present invention has been made to solve the above problems, and the load is always seated in a stable state regardless of the weight of the load and the operating speed of the lifting device during operation of the load balancing device in a balanced state. It is an object of the present invention to provide a load balancing device that can prevent the displacement of the landing position of the load and stop the suspended load without giving damage or damage to the suspended load.

[0012]

A load balancing apparatus according to the present invention comprises a load elevating mechanism for elevating a load, a drive section of a drive mechanism for driving the elevating mechanism, and a load detector for detecting the weight of the load. A weight storage unit that stores the weight of the detected load, a position detector that detects the position of the lifting mechanism, a speed commander connected to the operating lever that the operator commands the speed of the lifting mechanism, and a storage weight. And a load calculation unit that calculates the deviation of the detected weight of the load and a calculation unit that calculates the position of the lifting mechanism based on the signal from the speed commander and the output signal from the deviation calculation unit. The seating calculation unit that calculates the position change curve detects the seating of the load and performs control such that the operation of the lifting mechanism is stopped.

[0013]

The lift mechanism operates in response to a change in the amount of operation of the operation lever by the operator, and the load detector stores the load weight and stores the weight of the load as a target. It operates in two modes, the balanced mode, which operates with the deviation between the signal and the target weight.

In the raising / lowering mode which operates in response to a change in the operation amount of the operating lever, the raising / lowering drive signal is output by calculating the velocity command signal from the velocity commander in the arithmetic unit, The lifting mechanism carries out a lifting operation.

In the equilibrium mode, the weight of the load suspended by the lifting mechanism is detected by the load detector and stored in the weight storage unit. The stored weight stored and the detected weight of the suspended load are subjected to a deviation calculation by the deviation calculation section, and the calculated deviation signal is input to the lifting drive section, and the lifting mechanism moves the load up and down. At this time, the force of the worker applied to the load is the calculation signal itself output from the deviation calculation unit, and the load moves up and down at a speed corresponding to the applied force.

In the seating calculation section, which receives the position signal from the position detector that detects the position of the lifting mechanism and the load detection signal from the load detector during operation in the balance mode, the position of the lifting mechanism and the load are detected. Two input signals of the load are constantly monitored and the change characteristics are calculated. It appears that there is a certain pattern peculiar to the seating, which appears only when the load hung on the lifting mechanism is seated and does not appear by the operator's operation. By detecting, the load seating is judged and the operation in the balanced mode is interrupted.
Move to lift mode.

By the above, the load balancer can accurately determine the seating of the suspended load regardless of the weight of the load and the speed of the lifting device, and can accurately seat the suspended load at the desired place. The load balancer is very easy to handle.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the first embodiment shown in FIGS.

The parallel link type lifting mechanism 1 is driven up and down by a lifting driving motor 2 and a gear mechanism 3 to move up and down.
A suspending tool 5 for suspending the load 4 is provided at the tip of the load 4, and the load 4 is suspended. Further, an operation lever 7 of a speed command device 6 for commanding the ascending / descending speed of the elevating mechanism 1 is provided, and a position command signal S from the position command device 6 is input to a determination unit 8 and a V / f conversion unit 9 Is digitally converted by the above and is input to the target counter 12 via the mode selection unit 11 of the position calculation unit 10 and is input to the calculation unit 13 as the target position for the lifting mechanism 1.

The suspension 5 for suspending the load 4 is attached to the load detector 14 for detecting the weight W of the load 4, and the load signal WA from the load detector 14 is digitally converted by the A / D converter 15 to load the load. The signal WB is input to the load calculator 16 and the deviation detector 17, and the calculator 1 of the position calculator 10 is also input.
It is also input to 3.

A position detector 18 for detecting the position of the elevating mechanism 1 is provided in the elevating and lowering motor 2, and the position detection signal X is input to the current counter 19 of the position calculating section 10 to elevate and lower the mechanism 1. The current position XA is input to the calculation unit 13.

The weight W of the load 4 detected by the load detector 14 is stored in the weight storage unit 16 as a load signal WB based on a command from the determination unit 8. The position command S from the position command unit 6 and the position change signal SH from the calculation unit 10 are input to the determination unit 8. Here, when the content of the weight storage unit 16 is erased by the signal from the determination unit 8, the load weight W is not stored, and therefore the position command signal SA from the position calculation unit 6 is preferentially set to the position. The drive device 2 of the drive motor 2 that is input to the arithmetic unit 10 and drives the lifting mechanism 1.
0 is converted to analog by the D / A converter 21 and the lift command X
It is output as O, and the elevating mechanism 1 operates in a position mode in which the elevating mechanism 1 moves up and down in accordance with the movement of the operating lever 7.

When the weight storage unit 16 stores the loaded weight W, the stored weight WK stored in the weight storage unit 16 and the loaded load signal W from the load detection means 14.
The deviation from F is detected by the deviation detection unit 17, and the position calculation unit 10 operates in the load balance mode in which the deviation signal WR is used as a command to output the lifting command XO to the lifting mechanism 1. next,
The operation of the balanced load device according to the present invention will be described.

Until the load weight W is stored in the weight storage unit 16, the operation is performed in the position mode. In the position mode, the mode selection unit 11 is selected to the position mode side, and the operator operates the operation lever 7. As a result, the position command signal S from the position command unit 6 is digitally converted by the V / f converter 9 and input to the target counter 12 of the position calculator 10. Along with this, the value of the target counter 12 continuously changes with the operation amount of the operation lever 7.

At this time, the current counter 1 of the position calculator 10
In 9 the signal X from the position detector 15 is counted and the current position of the lifting mechanism 1 is given to the computing unit 13, and in the computing unit 13 the value of the current counter 19 and the value of the target counter 12 are constantly compared to raise and lower the mechanism. A deviation between the target position of 1 and the current position is obtained, and this deviation is converted into an analog signal by the D / A conversion unit 21 and output to the drive device 20 of the drive motor 2 as a lift command signal XO. This lift command signal XO is input as a drive signal to the drive device 20 of the drive motor 2 that drives the lift mechanism 1 up and down, and the lift mechanism 1 is driven up and down by the rotation of the drive motor 2 and the load suspended by the suspender 5 is lifted. Reference numeral 4 performs a lifting operation according to the operation amount of the operation lever 7.

At this time, the load detection value WB obtained by A / D converting the load detection signal WA from the load detector 14 is input to the weight storage unit 16, the deviation detection unit 17, and the calculation unit 13. Therefore, the position command signal S from the position command unit 6 and the position change signal SH from the calculation unit 13 are input to the judgment unit 8, and it is judged that both the position command signal S and the position change signal SH have become small. The load detection signal WA from the load detector 14 is stored in the weight storage unit 16 as the stored weight WK based on the determination command H.

Here, in the judging section 8, first, the position commander 6
After it is determined that the change of the position command signal S from the small area SAO has occurred, the position change signal S from the calculation unit 13 is determined.
It is determined that the change in H has become the minute region SHO, and the determination command H is output to the weight storage unit 16 and the weight storage unit 16 is output.
Stores the current weight.

When the weight storage unit 16 stores the load weight W, the operation mode shifts from the position mode to the load balancing mode, and the mode selecting unit 11 switches to the load balancing mode side.
A deviation between the load weight WF from the load detector 14 and the stored weight WK stored in the weight storage unit 16 is taken as a target by the deviation detection unit 17, and the position command XO for the lifting mechanism 1 is obtained. Deviation signal W to calculate
R is input to the position calculation unit 10.

The deviation signal WR input to the position calculator 10
Is the difference between the load weight WF and the memory weight WK, which is the force F itself applied by the worker to the load 4. In the position calculation unit 10, according to the magnitude of the deviation signal WR, the value of the target counter 12 is changed to load weight WF> memorized weight WK ... Decrease (down command) load weight WF <memorized weight WK. The target position of the elevating mechanism 1 is continuously changed by continuously changing the target position. As a result, the lift command signal XO is continuously output to the lift drive unit 20 of the lift mechanism 1 as in the position mode.

Since the control is performed in this way, the operator acts on the load 4 suspended by the suspension 5 in the ascending or descending direction by the force F.
Is added, the load detection signal WA from the load detector 14 is increased or decreased, and a deviation corresponding to the force F applied by the operator is generated between the memory weight WK and the load weight WF. The target position is continuously changed according to the magnitude of the deviation, and the lift command signal XO is output to the lift drive unit 20 of the lift mechanism 1, so that the lift mechanism 1 moves in the direction in which the worker applies the force F. Become. The speed of change in this moving position is based on the force F applied by the worker, and (memory weight WK)-(load weight WF) = (force F applied by the worker)

The force F applied by the worker is subjected to a calculation corresponding to a change in position in the calculation unit 13 and is multiplied by a constant gain constant, whereby the speed of movement of the position of the elevating mechanism 1 is added by the worker. The movement of the force F is proportional to the magnitude of the force F, and the operator does not need to be concerned with the weight W of the suspended load 4 so much.
The load 4 can be moved up and down with.

When operating in this load balancing mode,
In the position calculation unit 10, the value of the current counter 19 which gives the current position of the lifting mechanism 1 and the load 4 suspended in the lifting mechanism 1.
The load detection signal WB that detects the weight W of the above is constantly compared.

At this time, when the elevating mechanism 1 carries out the descending operation and the suspended load 4 tries to land, the position calculating section 1
The value XA of the current counter 19 of 0 starts to decrease in the descending direction, and the load signal WB from the load detector that detects the weight of the suspended load 4 starts to decrease as the load 4 starts to land. Since it is known from experiments that the current position and the load change characteristics when the load 4 starts to land, the calculation unit 13 has a value XA of the current counter 19 representing the position of the lifting mechanism 1 and The load signal WB from the load detector, which indicates the weight of the suspended load 4, is constantly monitored, and when the curve showing the characteristics at the time of landing appears, it is determined that the load 4 suspended by the lifting mechanism 1 has landed. By switching the operation mode from the load balancing mode to the position mode, the elevating mechanism 1 stops at the time of landing.

Experiments have also shown that the curve showing the characteristics at the time of landing always shows a constant characteristic regardless of the weight of the load 4 and the ascending / descending speed of the elevating mechanism 1. The weight of the load 4 and the elevating mechanism are shown. A stable landing can be realized regardless of the lifting speed of 1.

By detecting the landing as described above, it is not necessary to once switch to the position mode when the lifting mechanism 1 lands the suspended load 4 during the equilibrium mode operation, and the load 4 can be accurately positioned at a predetermined position. Can be seated on.

As described above, according to the present embodiment, the lifting mechanism can accurately seat a suspended load during operation in the load balancing mode without bouncing, so that the mode can be changed each time the load is seated. It is possible to provide a load balancing device with extremely good workability without switching the load balancing mode from the load balancing mode to the position mode.

[0037]

As described above, by carrying out the present invention, the load balancing device can accurately seat a suspended load during operation in the load balancing mode without bouncing the load. There is no need to switch the load balancing mode from the load balancing mode to the position mode each time the vehicle is seated. Also, regardless of the weight of the load and the speed of the lifting device, the load can always be seated in a stable state, so there is no displacement of the landing position of the load, and the suspended load will not be damaged or damaged due to impact or the like. It is possible to provide a load balancer that has a very good workability that is stopped without being given.

[Brief description of drawings]

FIG. 1 is a structural diagram of a mechanism of one embodiment of the present invention,

FIG. 2 is a control block diagram thereof,

FIG. 3 is an operation explanatory diagram when shifting to a load balancing mode of the present invention;

FIG. 4 is a correlation diagram of the position of the lifting mechanism at the time of seating detection of the present invention and the characteristics of the detected load of the load detector.

[Explanation of symbols]

1 ... Lifting mechanism, 2 ... Lifting drive motor, 4
… Load, 6… Position commander, 7… Operating lever,
8 ... Judgment part, 9 ... V / f converter, 10 ... Position calculation part, 11 ... Mode selection part, 12 ... Target counter, 13 ... Calculation part, 14 ... Load detector, 1
5 ... A / D converter, 16 ... Weight storage section, 17 ... Deviation detection section, 18 ... Position detection section, 19 ... Current counter,
20 ... Lifting / driving unit.

Claims (1)

[Claims] 1. A mechanism for raising and lowering a load, a driving means for driving the lifting mechanism for the load, a means for detecting the position of the lifting mechanism, a driving means including a position control means for the lifting mechanism, and a weight for the load. In a load balancing device that has a load detection means mounted near the load for detection and a position calculation means for calculating the position of the lifting mechanism of the load, the weight of the detected load and the position of the lifting mechanism are calculated. , A method of controlling a load balancer, which comprises detecting and controlling seating of a load.