KR960006518B1 - Load Compensation System of Hydraulic Elevator - Google Patents

Abstract

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Description

Load Compensation System of Hydraulic Elevator

1 is an overall schematic block diagram of a general elevator.

2 is a detailed block diagram of a control unit in FIG. 1;

(A) to (d) of FIG. 3 are speed pattern diagrams during an ascending operation.

(A) to (d) of FIG. 4 are speed pattern diagrams during the descent operation.

(A)-(c) of FIG. 5 is a flow control characteristic diagram of an upflow flow control valve.

(A)-(c) of FIG. 6 is a flow control characteristic diagram of a flow control valve for descending.

7 is a block diagram of the hydraulic elevator of the present invention.

8 is a detailed block diagram of a control unit according to the present invention in FIG.

9 is another exemplary embodiment of the present invention.

(A)-(e) of FIG. 10 is a timing diagram of each part of FIG.

* Explanation of symbols for the main parts of the drawings

1: oil tank 2: hydraulic oil

3: hydraulic pump 4: electric motor

5a, 5b, 6a, 6b, 10a, 11a-11c, 12a: Pipe line 7: Check valve

8: Electronic proportional flow control valve for up and down operation 9: Electronic proportional flow control valve for down operation

10: flow sensor 12: pressure sensor

13,13 ': control unit 14: hydraulic cylinder

15: pressure oil 16: plunger

17: Car 18: Rated rated speed command

19: Ascending leveling speed command 20: Adder

21: falling leveling speed command 22: amplifier

23: offset setting unit 24: subtractor

25, 36: Subtractor 26: Rectifier

27: reference triangle wave generator 28: falling pulse width modulator

29: rising pulse width modulator 30: falling current amplifier

31: rising current amplifier 32: switch

33: reference speed pattern generator 34: holding section

35: amplification unit 37: delay unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for compensating a load of a hydraulic elevator. In particular, an initial offset value of an electromagnetic proportional flow control valve is provided by a load measurement signal of the load detection device provided with a load detection device capable of detecting a load on the car side. The present invention relates to a load compensation system of a hydraulic elevator, which is adapted to properly adjust the load according to the load.

1 is an overall schematic block diagram of a general elevator, and as shown therein, an oil tank 1 storing hydraulic oil 2 and a hydraulic pump 3 for delivering hydraulic oil 2 in the oil tank 1; , According to the electric motor 4 for driving the hydraulic pump 3, a check valve 7 for preventing the flow of oil at the time of stopping, and an input of a control signal 8a to adjust the flow of the flow rate during the ascending operation. Electron-proportional flow rate control valve (8), electronic proportional flow rate control valve (9) for lowering operation to control the flow of the flow rate during the lowering operation in accordance with the input control signal (9a), and measuring the flow rate according to the measurement signal ( Pressure oil filled in the flow sensor 10 for outputting the 10a, the control signals 8a, 9a, the control unit 13 for overall control of the system, and the hydraulic cylinder 14 And a car 17 mounted on the plunger 16, where reference numerals 5a, 5b, and 6a are used. , 6b, 11a, 11b, and 11c are pipelines.

FIG. 2 is a detailed block diagram of the control unit 13 in FIG. 1, which shows the rising rated speed command 18, the rising leveling speed command 19, the falling rated speed command 20, and the falling leveling speed command. A reference speed pattern generator 33 which receives the 21 and generates an up and down reference speed pattern, and an amplifier 22 that receives the output signal of the flow sensor 10a and converts the same into the same level as the reference speed pattern; And an offset setting unit 23 for setting an offset by receiving the rising rated speed command 18 and the falling rated speed command 20 and generating an output level of the amplifying unit 22 to generate the reference speed pattern. An adder 25 that adds an initial offset value output from the offset setting unit 23 to a speed difference value output from the subtractor 24 and a subtractor 24 for obtaining a speed difference compared to the output pattern of the unit 33; And a rectifier 26 for amplifying the output signal of the adder 25 with a predetermined amplification degree. A falling pulse width modulator 28 and a rising pulse width modulation for outputting a pulse width modulated signal from the rectifier 26 using the output signal of the reference triangular wave generator 27 as a control signal of a square wave; The unit 29, the output pulses of the falling pulse width modulating unit 28 and the rising pulse width modulating unit 29 are amplified, respectively, and the proportional flow control valve 9 for the lowering operation and the electronic proportionality for the raising operation. It consists of a falling current amplifier 30 and a rising current amplifier 31 outputted as a control signal of the flow control valve 8, the operation of the conventional elevator configured as described above with reference to FIGS. The explanation is as follows.

In FIG. 3, when the operation command in the upward direction is output, the hydraulic pump 3 is driven by the electric motor 4 at time t ₀ after the door is closed, whereby the hydraulic oil 2 in the oil tank 1 It is discharged from the hydraulic pump (3), which passes through the conduits (5a) and (5b), and then into the oil tank (1) through the elevating electromagnetic proportional flow control valve (8) and conduit (6a) in a fully open state. Come back.

When the rising rated command 18 is output at time t ₁ , as shown in (a) and (a '), the rising reference speed pattern starts to be output from the reference speed pattern generator 33 and is gradually accelerated to be constant at time t ₂ . Speed.

Further, at the time t ₁ , the initial setting level V ₁ is output from the offset setting unit 23 as shown in (a) of FIG. 5 by the rising rated speed command 18, and then gradually the reference speed pattern. This increase reduces the opening degree of the rising electromagnetic proportional valve 8, and thus reduces the amount of hydraulic oil 2 returned to the oil tank 1 through the conduit 6a, whereby the excess hydraulic oil is checked. The valve 7 → the flow rate sensor 10 → the pipe line 11b → the pipe line 11a are supplied into the hydraulic cylinder 14 via the valve.

On the other hand, the plunge 16 is moved in the upward direction by the oil supplied, whereby the car 17 is raised. The flow rate of the hydraulic oil 2 supplied to the hydraulic cylinder 14 is measured by the flow rate sensor 10, wherein the measured flow rate signal 10a is at the same level as the reference speed pattern through the amplifier 22. After conversion to, the subtracter 24 is compared with the reference speed pattern.

The speed difference signal output from the subtractor 24 is added by the adder 25 and the controllable initial offset signal of the electromagnetic proportional flow sensor 10, which is an output signal of the offset setting unit 23. For example, it is amplified by a predetermined amplification through the PID controller 26, and supplied to the rising pulse width modulator 29 for controlling the pulse width using the amplified signal, where the reference triangular wave generator 27 Is modulated by the output signal and output as a square wave control signal.

This control signal is supplied to the rising current amplifier 31 and amplified to an appropriate level. The amplified signal is used as the electromagnetic proportional solenoid driving signal 8a of the electromagnetic proportional flow rate control valve 8 for the rising operation. do.

After the discharge by the hydraulic pump 3 is controlled by the solenoid driving signal 8a, the flow rate returned to the oil tank 1 is controlled, and as a result, the flow rate supplied to the hydraulic cylinder 16 is equal to the reference speed pattern. Controlled to match.

In addition, as soon as the elevator reaches a predetermined position immediately before the target floor, the rising leveling speed command 19 is outputted, and the reference speed pattern is decelerated and operated at a constant low speed as shown at time t ₃ in FIG. At this time, the amount of hydraulic oil returned to the oil tank 1 is adjusted so that the flow rate supplied to the hydraulic cylinder 14 by the rising electromagnetic proportional flow control valve 8 matches the reference speed pattern.

When the elevator reaches the target floor through such a process, the speed command is not output at time t ₄ , and the offset set amount is also "0", and the electromagnetic proportional flow control valve 8 for the ascending operation maintains the full opening state. Since the flow rate of the hydraulic oil flowing to the check valve 7 is also " 0 ", the check valve 7 is closed, which causes the car 17 to be stopped, thereby driving the motor 4 at time t ₅ . It stops and the hydraulic pump 3 also does not discharge oil.

Next, the descent operation will be described. When the falling operation command is outputted, after the door is closed, the falling rated speed command 20 is outputted at time t ₁ ′ as shown in FIG. 4A, and the falling contact 32 is closed at this time. Then, as shown in (a) of FIG. 4, the falling reference speed pattern starts to be output from the reference speed pattern generator 33 and gradually accelerates to become a constant speed at time t ₂ ′.

In addition, the initial offset amount V ₁ ′ ((a) of FIG. 6) which enables the electronically proportional flow rate control valve 9 for descending to be controlled by the falling rated speed command 20 at time t ₁ ′ is an offset setting unit. It is output from (23). Then, when the reference speed pattern gradually increases, the opening state of the electromagnetic proportional flow rate control valve 9 for descending increases, so that the pressure oil 15 in the hydraulic cylinder 14 flows from the conduit 11a to the conduit 11b to the flow rate sensor 10. ¡Æ the plunger 16 is moved in the downward direction and the car 17 is lowered because the flow rate flow valve 9 for lowering operation flows to the oil tank 1 through the pipeline 6b.

At this time, the flow rate passing through the electronic proportional flow rate control valve 9 for descending is controlled in the same manner as in the rising, so that the flow rate discharged from the hydraulic cylinder 14 is controlled to match the reference speed pattern.

Further, when the car 17 reaches a predetermined position immediately before the target floor, the falling leveling speed command 21 is outputted, and the reference speed pattern is decelerated at a time t ₃ ′ in FIG. In this case, the flow rate discharged by the electronic proportional flow rate control valve 9 for descending is controlled to match the reference speed pattern.

When the car 17 arrives at the target floor, the speed command is interrupted at time t ₄ ', and the offset set amount is also " 0 " so that the down proportional flow rate control valve 9 is completely closed. Due to this, the driving of the car 17 is stopped, and at the time t ₅ , as well as the lowering switch 32 is opened, the driving command in the downward direction is also blocked.

Such a system causes a characteristic change due to the pressure change, that is, if the pressure of the hydraulic oil 15 in the hydraulic cylinder 14 is P, the electromagnetic proportional flow rate control valves 8 and 9 when P = P _1. The applied voltage vs. flow rate characteristics of) are the same as in (a) of FIG. 5 and (a) of FIG. Therefore, the electromagnetic proportional flow control valves 8 and 9 have a range that is not controlled up to the applied voltages of V ₁ and V ₁ ′, respectively.

If the pressure of the hydraulic oil 15 in the hydraulic cylinder 14 is P> P ₁ , the rising electromagnetic proportional flow control valve 8 has an uncontrolled range as shown in FIG. 5B, that is, V ₂ becomes V ₂ > V ₁ and the overall characteristic is shifted to the right by V _2-1 .

If the velocity pattern of the car 17 is equal to (b) of FIG. 3 in the case of P = P ₁ , when the same offset value V ₁ is applied in the case of P ₁ > P, the car 17 does not start initially and the third Since it starts moving at time t ₁₁ as shown in (d) of FIG. 3, the reference speed pattern of FIG. 3 (a) and the initial speed error are largely generated, which causes the car l7 to start rapidly at time t ₁₁ . The initial starting shock is large.

In addition, when P> P ₁ during the descent operation, the falling electromagnetic proportional flow control valve 9 is in an uncontrolled range, that is, V ₃ 'becomes V ₃ '<V ₁ 'and the overall characteristic is V ₁ ' -V. ₃ 'to the left.

Therefore, in the case of P = P ₁ , if the speed pattern of the car 17 is equal to (b) outside the fourth degree, if the same offset value V ₁ ′ is applied in the case of P> P _1, the electromagnetic proportional flow control valve for descending operation ( 9) has already begun opening and the flow rate is discharged from the hydraulic cylinder 14 to the oil tank 1, so when the starting command is output as shown in (c) of FIG. Becomes large, which causes vibration to become one of the causes of lowering the riding comfort.

In addition, when P <P ₁ is raised, the characteristic of the solenoid proportional valve 8 becomes V ₃ <V ₁ , and as shown in (c) of FIG. 5, the overall characteristic is left by V ₁ -V ₃ than when P = P _1. When the start command is output as shown in (c) of FIG. 3, the car 17 starts rapidly, which causes initial start shock and vibration.

At the time of descending, the characteristic of the proportional flow control valve 8 for ascending operation becomes V ₂ '> V ₁ ', and the overall characteristic is V ₂ '-V than when P = P ₁ as shown in FIG. _Since the car 17 does not start at the beginning and starts to start at time t ₁₁ 'as shown in (d) of FIG. 4, the initial starting shock is increased.

As described above, in the conventional system, since the initial offset amount cannot be adjusted according to the pressure change due to the load variation, there is a problem in that the overall riding comfort is reduced due to the characteristic change caused by the load variation.

The present invention is to create a load compensation system that reduces the suppression of the starting shock and the generation of vibration by adjusting the initial offset amount according to the load in order to solve such a conventional problem, will be described in detail with reference to the accompanying drawings.

7 is an overall block diagram of the hydraulic elevator of the present invention, as shown therein, an oil tank 1 for storing hydraulic oil 2 and a hydraulic pump 3 for delivering hydraulic oil 2 in the oil tank 1. ), The electric motor 4 for driving the hydraulic pump 3, the check valve 7 for preventing the flow of oil during stop, and the flow of the flow rate during the ascending operation according to the input control signal 8a. Electron-proportional flow rate control valve (8) to adjust, the electro-proportional flow rate control valve (9) for downward operation to adjust the flow of the flow rate during the descent operation according to the input control signal (9a), and measure the flow rate and measure accordingly The flow rate sensor 10 for outputting the signal 10a, the pressure detector 12 which detects the oil pressure input to the cylinder 10, and totally control a system, and the output signal of the said pressure detector 12 The initial offset value of the electromagnetic proportional flow control valves (8) and (9) is adjusted according to the load. It consists of a control unit (13 '), and a pressure oil 15, a car 17 provided on an upper part of the plunger (16) filled with the hydraulic cylinder (14) to which.

FIG. 8 is a detailed block diagram of the control unit 13 'according to the present invention in FIG. 7, as shown in this way, the rising rated speed command 18, the rising leveling speed command 19, and the falling rated speed command 20. As shown in FIG. And an amplifying unit receiving the falling leveling speed command 21 and converting the reference speed pattern 33 to generate the rising and falling reference speed patterns and the output signal of the flow sensor 10a to the same level as the reference speed pattern. (22), an offset setting unit (23) for setting an offset by receiving the rising rated speed command (18) and the falling rated speed command (20), and an output level of the amplifying unit (22). A subtractor 24 for obtaining a speed difference compared to the output pattern of the speed pattern generator 33 and an initial offset value output from the offset setting unit 23 to a speed difference value output from the subtractor 24; An amplifier 25 and amplifying the output signal of the adder 25 with a predetermined amplification degree. A falling pulse width modulator 28 for modulating a pulse width modulated signal from the rectifier 26 using the output signal from the current flow section 26 and the reference triangle wave generator 27 and outputting the control signal of a square wave; Amplifying the output currents of the rising pulse width modulating unit 29, the falling pulse width modulating unit 28, and the rising pulse width modulating unit 29, respectively, to lower the driving ratio of the electromagnetic proportional flow rate control valve 9, In the operation control system of a hydraulic elevator comprising a falling current amplifier 30 and a rising current amplifier 31 outputted as a control signal of the electromagnetic proportional flow rate regulating valve 8 for the rising operation, a rising rated speed command ( 18) holding section 34 for holding the output signal 12a of the pressure detector 12 by the falling rated speed command 20, and amplifying section for amplifying the output signal of the holding section 34 to a predetermined level. And an output component of the amplifying section 35 to the output output component of the offset setting section 23. Delay unit for supplying to the reference speed pattern generator 33 by delaying the adder 36 and the rising and falling rated speed commands 18 and 20 provided to one side input of the adder 25 by a predetermined time ( 37), which will be described in detail with reference to FIG. 10 attached to the operation and effect of the present invention configured as described above.

In Fig. 7, when the operation command in the ascending direction is output from the operation control device, the hydraulic pump driving motor 4 is rotated at time t ₀ after the door is closed to drive the hydraulic pump 3. Further, at time t ₀ , the rising rated speed command 18 is turned on as shown in FIG. 10A, and the load pressure output signal 12a of the pressure detector 12 provided in the conduit 11b is provided by the speed command 18. ) Calculates the average value of the load pressure output signal 12a from time t _{0 to} t ₆ by the holding section 34, and outputs the voltage V ₁ at time t ₆ as shown in FIG.

Here, the time t ₆ is set not to exceed the delay time t ₁ -t ₀ of the delay unit 37. In addition, calculating the average value for a predetermined time is to reduce the load pressure fluctuations caused by the movement of the passengers during boarding, as shown in (b) of FIG.

The output signal of the holding section 34 is " 0 " when the rising rated speed command 18 is turned off. This output signal is a difference signal from the V ₀ of the pressure detector 12 at no load by the amplifying section 35. It is amplified by a predetermined amplification degree k and the value of K · (V ₁ -V ₀ ) is output. ((D) of FIG. 10)

The output value of the amplifier 35 is added to the output value of the offset setting unit 23 at no load by the adder 36 and output. In addition, the rising rated speed command 18 is outputted at a time t ₁ after a predetermined time delay as shown in (e) of FIG. 10 through the delay unit 37. The speed pattern generator 33 The speed pattern is generated to perform the lift operation in the same manner as the conventional apparatus.

In addition, when the driving control device outputs the command of the driving direction in descending operation, the initial offset value is calculated by the descending rated speed command 18 in the same manner as in the rising operation, and the lowering operation is performed as in the conventional apparatus. .

Therefore, the initial offset value according to the load is calculated by the input of the hydraulic cylinder 14 side, and the value (V) of the controllable points of the electromagnetic proportional flow control valves 8 and 9 by this calculated value according to the load variation. ₁ , V ₂ , V ₃ ), (V ₁ ', V ₂ ', V ₃ ') can be adjusted to prevent initial sudden start or initial start delay due to load fluctuations. As shown in (b) of FIG. 3 or (b) of FIG. 4, the traveling speed of the car 17 can be controlled.

On the other hand, according to another embodiment of the present invention, the lower portion of the floor 38 of the car 17 without detecting the load based on the input of the flow sensor 10 installed in the conduit 11b as shown in FIG. It is shown that a separate load detection device (eg, load measurement device using an automatic transformer) is used.

As described in detail above, in order to reduce the characteristic change caused by the load variation of the present invention, a pressure detector capable of detecting the pressure in the cylinder is installed in the pipeline, and when the operation command is output, the output is held and the held value is recorded. By adding to the initial offset value, there is an effect of ensuring a stable ride even if the load changes.

Claims (2)

An oil tank (1) storing hydraulic oil (2), a hydraulic pump (3) for delivering hydraulic oil (2) in the oil tank (1), an electric motor (4) for driving the hydraulic pump (3), and , Check valve (7) for preventing the flow of long-term, electronic proportional flow control valve (8) for adjusting the flow of the flow in the up-driving operation according to the control signal (8a) input, and the control signal (9a) input The flow rate control valve 9 for the down-driving operation for adjusting the flow of the flow rate during the down-driving operation, the flow sensor 10 for measuring the flow rate and outputting the measurement signal 10a according to the flow rate, and the cylinder 10 Pressure detector 12 for detecting the hydraulic pressure input to the), and total control of the system, and, based on the output signal of the pressure detector 12, electromagnetic proportional flow control valve (8), (9) according to the load A control unit 13 'for adjusting an initial offset value of the oil, a pressure oil 15 filled in the hydraulic cylinder 14, and the plunger 16 Load compensation system of the hydraulic elevator, characterized in that consisting of a car (17) installed on the top. The holding section 34 for holding the output signal 12a of the pressure detector 12 by the rising rated speed command 18 and the falling rated speed command 20, The output component of the amplifying section 35 that amplifies the output signal of the holding section 34 to the predetermined level and the output component of the offset setting section 23 are added to add the output section of the adder 25. An adder 36 provided as one input and a delay unit 37 for supplying the reference speed pattern generator 33 by delaying the rising and falling rated temperature command 18, 20 for a predetermined time. Load compensation system of the hydraulic elevator, characterized in that.