EP0643006B1 - Method and system for controlling a hydraulic lift - Google Patents

Abstract

With this method, accurate direct arrival at a floor can be achieved without travel at creep speed being necessary. Here, the car is controlled as a function of displacement in the deceleration phase, for which purpose a control range (CS) is formed which is divided into percentage values. The percentage values are put into tabular form in relationship to measured actual displacement values. When a certain actual displacement value occurs, the corresponding percentage value is multiplied by the value of the control range (CS) and if need be a control deviation (CO) and a pilot-control signal (SO) are added to the product, the sum forming the actual control signal (S) used in each case during the deceleration phase, which control signal (S) is fed to a control-valve arrangement. <IMAGE>

Description

The invention relates to a method and a device for Control of a hydraulic elevator, one Control device generates control signals that one Control valve assembly are supplied, which the flow regulates a hydraulic fluid in such a way that a cabin of the Elevators accelerated, moved at constant speed and when one arrives the braking point signaling shaft information is delayed.

With such elevators, the driving speed depends more or less strongly from changes in cabin load and the temperature of the hydraulic hydraulic fluid, whereby the controlled by a control valve Flow changes accordingly and an exact entry is not possible on one floor. To this lack will fix shortly before reaching the floor on a small, constant creep speed switched, so through changes in load and / or temperature resulting differences in height of the breakpoint compensated can be (Fig. 3). This leads to an extension of driving and waiting times for users and requires high energy consumption. With hydraulic lifts the length of the creep speed is also known to be from depending on the load and temperature conditions.

With the German patent 36 38 247 is one Device for a hydraulic elevator, with the disadvantages mentioned above are to be remedied. Here, a control device is provided which Determining the speed behavior of the cabin Output signals generated that fed to a control valve become. The control valve leads from one Hydraulic fluid source in According to the output signals the cabin driving hydraulic cylinder to or vice versa. In one connected to the control device via a computing unit Reference speed values are stored in the memory correspond to certain operating states, which on different load and / or temperature conditions related are. A sensor located on the cabin detects the Actual speed and passes it through a converter unit the computing unit. Here, the during the Acceleration phase measured actual speed and one predetermined reference speed formed a difference due to which the computing unit a Control speed curve calculated. This Control speed curve is saved and during the Deceleration phase used to the actual speed towards the value of the specified reference speed correct. This is said to be accurate and quick Control of the destinations and thus the Operating time of the elevator can be shortened. Here comes the no control loop and no regulation to adapt the However, control device having the brake application time not without crawl speed.

The invention has for its object a method and a device for performing the method according to Propose the preamble of claim 1, the one Direct entry on one floor without travel Allows creep speed.

This object is achieved by the in claims 1 and 8 characterized invention solved. Here the cabin is in the delay phase controlled depending on the route, for what purpose a trip-specific control area is formed, which in percentage values is divided. The percentage values are measured in tabular form in relation to Actual values set. When a certain one arrives The actual percentage value becomes the corresponding percentage value with the Multiplied the value of the control area and from that the current used during the delay phase Control signal formed. This becomes a control valve arrangement fed.

The advantages achieved with the invention can be seen in that driving and waiting times are reduced, that the Hydraulic fluid heats up less and energy consumption goes back. Through the proposed direct entry using a control valve arrangement with an in Building simple position feedback becomes an accurate stop achieved without level adjustment and in relation to Driving comfort and minimum driving time an optimal deceleration result achieved. There remain changes in load and temperature without affecting the stopping accuracy. It is advantageous also that the acceleration of the cabin and the ride with Nominal speed can be unregulated, which is based on has a favorable effect on the efficiency of the hydraulic drive. Another advantage is that the application that interact with a control device Control valve arrangement the automatic determination of elevator-specific parameters possible by means of a learning trip makes. This eliminates the manual adjustment work at There is no need to commission the elevator.

Fig. 1

eine schematische Darstellung der erfindungsgemässen Einrichtung,

Fig. 2

eine schematische Darstellung einer Regelventilanordnung der Einrichtung gemäss Fig. 1,

Fig. 3

ein Geschwindigkeits/Zeit-Diagramm eines hydraulischen Aufzuges gemäss Stand der Technik,

Fig. 4

ein Geschwindigkeits/Zeit-Diagramm und ein Steuersignal/Zeit-Diagramm eines mit der erfindungsgemässen Einrichtung gesteuerten hydraulischen Aufzuges, und

Fig. 5

ein Blockschaltbild eines Wegreglers der Einrichtung gemäss Fig. 1.

Advantageous further developments and improvements are possible through the measures listed in the dependent claims. The invention is explained in more detail below with reference to an embodiment shown in the drawing.
Show it:

Fig. 1

2 shows a schematic representation of the device according to the invention,

Fig. 2

1 shows a schematic illustration of a control valve arrangement of the device according to FIG. 1,

Fig. 3

a speed / time diagram of a hydraulic elevator according to the prior art,

Fig. 4

a speed / time diagram and a control signal / time diagram of a hydraulic elevator controlled by the device according to the invention, and

Fig. 5

2 shows a block diagram of a position controller of the device according to FIG. 1.

In Fig. 1, 1 denotes a cabin, which means one having a piston 3 and a cylinder 4 hydraulic lifting device 2 can be set in motion can. The movement is transmitted by means of a rope 5 the two attached to the piston 3 rollers 6, two on the Cabin 1 fixed rollers 7 and a fixed attached Roll 8 runs, the cabin 1 being guided in a shaft 9 becomes. In the shaft 9 arranged shaft switch 10, one with the cabin 1 connected sensor 11 and one Command control 12 are preferably digital Control device 20 connected. The sensor 11 has a Wheel on that on a rope stretched along the shaft 9 rolls, and emits path signals in the form of pulse signals. Of the Sensor 11 can be as described or otherwise work mechanically, but also electrically or optically. A with reference to Fig. 2 control valve arrangement described in more detail below 13 is with the output of the control device 20 electrically connected and via hydraulic fluid lines on the hydraulic lifting device 2 and one Hydraulic fluid source 14 connected.

The command control 12 directs the control device 20 Driving commands too. Brake application signals are from her Control unit 21, which is part of the Control device 20 is. The brake application signals come from the shaft switches 10, which at certain intervals in front of the Floor floors are attached. Brake application signals can can also be derived from the sensor 11 by for example summed up for a certain number Path signals generated corresponding shaft information becomes. The control device 20 generates a signal S, which the control valve assembly 13 is supplied.

The control unit 21 is equipped with a tachometer signal converter 22 connected, which is supplied by the sensor 11 Travel signals into actual speed values vi or actual travel values si implements. A speed controller 23 is on the input side an output of the Tacho signal converter 22 and with one Speed setpoints vs output of a Speed setpoint sensor 24 connected is connected on the input side to the control unit 21. Via another one connected to the control unit 21 Input, the speed controller 23 can be reset or be started. For the Speed controller 23 can be a conventional PID controller be used. 25 is a below with reference to FIG. 5 designated path controller, the on the input side with the control unit 21 and with a Output of the speedometer signal converter 22 outputting actual values si connected is. A path 26 belongs to path controller 25, in which assignments of actual path values si to percentages % S values of one described later with reference to FIG. 4 Control area CS are stored. A Switching device 27 is with an output of the control unit 21, the output of the speed controller 23, the output of the path controller 25 and the input of a DA converter 28 connected. The output can be switched by means of the switching device 27 of the travel controller 25 upon arrival of the brake application point signaling shaft information to the input of the DA converter 28 are switched. The output of the DA converter is connected to an amplifier 29, the output of which Output of the control device 20 forms.

The control valve arrangement 13 shown in FIG. 2 has two similar electro-hydraulic throttle valves 30, 30 '. The following description for the throttle valve 30 for Control of the lowering process applies in the same way for the Throttle valve 30 'shown in mirror image for lifting the Cabin, in the same, but with a tick Reference numbers are used.

A main piston 32 is guided in a valve chamber 31 protrudes from the rear a piston rod 33. Around this is a pilot valve 34 with a without a functional connection Electromagnet 35 arranged with the output of the Control device 20 (Fig. 1) is electrically connected. The piston rod 33 protrudes out of the pilot valve 34 at the rear and carries at its end a stop 36, between which Stop 36 and the pilot valve 34, a compression spring 37 is arranged is. The compression spring 37 acts on the force of the electromagnet 35 against. By means of the compression spring 37 is a closed loop with internal feedback in the Pilot valve 34 made. The pilot valve is in one Connection line 38 arranged and controls its flow. The connecting line 38 connects a front chamber 39 and a rear chamber 40 of the valve chamber 31 with each other.

The front chamber 39 has an inlet C which over a variable passage 39.1 with an outlet T is connected, which opens into a tank 42. Inlet C is connected to the cylinder 4 of the lifting device 2. The rear chamber 40 is also via a drain line 41 connected to the tank 42. Located in the drain line 41 an electromagnetic closing valve 44.

The control valve arrangement works with a lifting force feedback, i.e. the force of the compression spring 37, the Represented position of the main piston 32 is measured and serves as a feedback signal. This ensures that the force of the electromagnet 35 or the strength of the control signal S proportional to the position of the Main piston 32 is. This solution has a good dynamic Behavior on and is inexpensive and easy to set up. However, other, e.g. hydraulic, electrical or mechanical returns are used.

In the throttle valve 30 ', the outlet T' is the front one Chamber 39 'also connected to tank 42. One with P designated inlet is with a motor-driven pump 45 of the pressure fluid source 14 in connection. The pump 45 sucks from the tank 42. The throttle valve 30 'needs in its drain line 41 'no closing valve.

The inlets C and P are connected via a connecting line 47 a check valve 48 connected to each other. The Check valve 48 acts so that the hydraulic fluid from the lifting device 2 not in the direction of the pump 45 can flow back.

When the cabin 1 is at a standstill, the signal S is zero and that Throttle valve 30 is closed (hydraulically). this will reached by a slightly open pilot valve 34 so that the valve chambers 39 and 40 are connected to one another and the one in the rear chamber 40 on the large rear Surface of the main piston 32 acting pressure in the direction the chamber 39 moves. The closing valve 44 is at Standstill and upward travel of cabin 1 closed. The Throttle valve 30 'is open when the cabin 1 is at a standstill.

If there is a call to go down, it generates Control device 20 a signal S that a closed Position of the throttle valve 30 corresponds, i.e. the Pilot valve 34 is opened to the extent that Opening cross-section is larger than that of the drain pipe 41. When the closing valve 44 subsequently opens the main piston 32 remains in spite of pressure medium outflow line 41 in its closed position. After that the electromagnet 35 receives a signal S reversed proportional signal S ', which in principle follows causes: The force of the electromagnet 35 works counter the force of the compression spring 37. When the main piston 32 through Differences in pressure in the chambers 39, 40 shifted so far the flow through the connecting line 38 is the same size as that in the drain line 41, so stops the main piston 32 and remains in this position until that Control signal S is changed.

When the signal S increases, that is, it decreases Signal S ', the opening cross section of the Pilot valve 34 and the main piston 32 is due to the retracted lower pressure in the rear chamber 40. The passage 39.1 is now released and the pressure medium flows from the lifting device 2 into the tank 42, whereby the cabin 1 lowers. The signal S is as long enlarged until the cabin 1 the desired Maximum speed reached. Remains at this level the signal S until the brake application signal occurs. From there on the signal S becomes dependent on the control device 20 reduced again, causing the main piston 32 in the direction on the passage 39 until it closes it completely, to bring the cabin to a standstill. At this moment the closing valve 44 is also closed. The Throttle valve 30 'remains during the descent unchanged open.

The throttle valve 32 'for lifting the cabin 1 works basically the same as the throttle valve 32, but with the difference that the signal S 'for the electromagnet 35 'is proportional to the signal S. If a call is made to Upward travel, the pump 45 is turned on Hydraulic fluid into chamber 39 'and through the valve gap 39.1 'pumps into the tank 42. Thereafter, the pilot valve 34 ' a signal S ', causing an opening of the connecting line 38 'leads. Then pressure medium flows from the front Chamber 39 'to the rear chamber 40' at a particular one The amount of the signal S is the opening cross section of the Pilot valve 34 'larger than the cross section of the Drain line 41 '. This increases the pressure in the rear Chamber 40 'on and main piston 32' moves forward and narrows the valve gap 39.1 '. As soon as the pressure in the Chamber 39 'exceeds the pressure in the lifting device 2, the check valve 48 opens and the cabin 1 sets moving. When the valve gap is completely closed 39.1 'the elevator moves upwards at maximum speed.

The acceleration process and the drive with nominal or Operating speed can be unregulated. In the Upward travel can thus the full unthrottled performance of the Pump 45 can be used. The maximum speed of the Cabin 1 is then determined by the pump output. The The speed of the descent can be adjusted accordingly dimensioned aperture in the drain line of the Lifting device 2 are limited.

In the illustrated embodiment there are two Pilot valve arrangements are provided, depending on the direction of travel only one is active at a time. In another Design variant is only a pilot valve arrangement for both directions of travel provided, alternating both Throttle valves 30, 30 'controls.

FIG. 3, which represents the prior art, also includes v denotes the speed and t denotes the time. Depending on The load and temperature of the hydraulic fluid result during different speed / time characteristics during the deceleration phase A, B, so that for an accurate entry a Creep speed C is required.

S0, S1, S2

bestimmte Werte des Steuersignales S,

CS

einen Steuerungsbereich,

H

einen Hysteresewert und

CO

eine Steuerabweichung.

According to FIG. 4, speed and time are again designated by v and t, the v-axis also being associated with the control signal S generated by the control device 20. A characteristic curve D represents the actual speed curve, while a characteristic curve E represents the curve of the control signal S at the output of the control device 20 while the cabin 1 is traveling. Also mean:

S0, S1, S2

certain values of the control signal S,

CS

a control area,

H

a hysteresis value and

CO

a tax variance.

5 is the table 26, by means of which during the Delay phase control signals assigned to the actual path values si are formed for the control valve assembly 13 with connected to the input of a multiplier 25.1, each a corresponding to the current travel actual value si ' percentage value% S of the control area with the calculated value of the control area CS multiplied. The outcome is to improve the control result of the multiplier 25.1 with the input of an adder 25.2 connected to the product of the multiplier 25.1 Control deviation CO and the pilot signal S0 added and the output of which forms the output of the displacement controller 25.

The control device 20 described above operates as follows. When a drive command from command control 12 arrives, speed controller 23 is reset or activated by control unit 21, and the input of DA converter 28 is switched to the output of speed controller 23 by switching device 27. The cabin 1 is now controlled during the acceleration phase and travel at constant speed by comparing the actual speed values vi with the speed setpoints vs, the control signal S at the output of the control device 20 according to the characteristic curve E (FIG. 4). After the arrival of a driving command, the cabin 1 starts to move at the start time t1 and at the same time a first value S1 of the control signal S is stored (FIG. 4). If the cabin 1 reaches a braking point of application, the relevant shaft switch 10 or the sensor 11 sends a shaft information to the control unit 21, whereupon the delay phase is initiated. Here, the path controller 25 is activated and its output is switched to the input of the DA converter 28 by means of the switching device 27. At the same time, a second value S2 of the control signal S is stored and a control area CS according to the relationship CS = S2 - S1 + H (FIG. 4), where S1 and S2 are the first and second values of the control signal S and H is a hysteresis value which is determined as described in more detail below. The displacement controller 25 now works in such a way that, as already described with reference to FIG. 5, the percentage values% S corresponding to the displacement actual values si are multiplied by the calculated value of the control range CS and the control deviation CO and the pilot control signal S0 are added, whereby CO = S2 - S0 - CS is (Fig. 4). The sum determined in this way is fed via the switching device 27 and the DA converter 28 to the amplifier 29 (FIG. 1), at the output of which it appears as the respectively current control signal S.

As already mentioned in the description of FIG. 2, the selected control valve assembly 13, the position of Master piston 32 exactly proportional to the control signal S. The control signal S generated by the speed controller 23 until the time of braking application load and temperature dependent. But since the control area CS for the Delay phase to the current one while driving constant load and temperature conditions based on the values S1, S2, H is redefined, can be accurate Direct entry can be achieved without a level adjustment is required.

The hysteresis value H becomes as follows during a learning trip determined: The control signal S is increased until the Speed reaches a predetermined value. At If the specified value is reached, the strength of the Control signal S measured and stored. After that it will Control signal S further increased and after a while again downsized until the given value of speed is reached again. Then the strength of the control signal S measured again and one of the two measured values Difference formed, which represents the hysteresis value H.

More elevator specific with direct entry in Related parameters such as a Pilot control signal S0 or a limit control signal SL also determined during a learning trip:

Pilot control signal S0:

On the one hand, the pilot control signal S0 causes an immediate Departure of the elevator car after the start command, on the other hand the starting jerk can be significant with the pilot control signal S0 can be reduced. To determine the pilot control signal S0 the electromagnet 35 of the control valve arrangement for as long with a gradually increasing control signal S pressurized until the elevator car starts moving. That included determined control signal is around a constant value reduced and stored as pilot signal S0. At the The control valve arrangement 13 becomes a drive command directly applied to the pilot signal S0.

Limit control signal SL:

The limit control signal SL is that control signal S, at which the main piston 32 of the control valve assembly 13 its End position reached. The control device 20 works in such a way that the value of the control signal S is the value of the Limit control signal SL can never exceed. As above A hydraulic elevator is usually explained speed controlled. With that during one Learning drive certain limit control signal SL is a uncontrolled operation during constant driving and one position-controlled operation during the subsequent Delay phase feasible.

In the case of speed-controlled operation, part of the of the hydraulic fluid source 14 conveyed hydraulic fluid returned to the tank 42 by means of an overflow line. In the case of uncontrolled operation, the control valve arrangement 13 is also used the limit control signal SL, so that the entire Delivery rate of the hydraulic fluid source 14 in the Lifting device 2 is effective, reducing the efficiency of the Lifting device 2 is significantly improved. The transition from uncontrolled constant travel to controlled travel Deceleration runs without default, because the value of the Limit control signal SL even with a previous unregulated Operation is such that the main piston 32 the Limit control signal SL can follow immediately. For determination of the limit control signal SL becomes the coil of Control valve arrangement as long as with a gradual increasing control signal S is applied until the The elevator car speed no longer increases. The the control signal determined in the process is generated by the control device 20 stored as a limit control signal SL.

The device according to the invention can preferably by means of of a microcomputer system can be realized.

Claims (10)

1. Method for the control of an hydraulic lift, wherein a regulating equipment (20) with the aid of a measuring sensor (11), which stands in connection with a cage (1) of the lift, produces control signals (S), which are fed to a regulating valve arrangement (13), which regulates the throughflow of a pressure fluid in such a manner that the cage (1) is accelerated in upward or downward direction, moved at operating speed and retarded on the arrival of a shaft information signalling the brake application point, wherein the measuring sensor (11) receives travel signals and the cage (1) is regulated in dependence on travel in the retardation phase, wherein a first value of the control signal (S) is ascertained and stored in the starting instant of the cage (1) after the input of a travel command, a second value (S2) of the control signal (S) of the regulating equipment (20) is stored on the arrival of the brake application signal, and a control range is formed by the difference of the second and first value of the control signal, characterised in that actual travel values (si) are produced from the travel signals during the retardation phase, each actual travel (si) is associated with a percentage value (%S) of the control range, the percentage values (%S) are multiplied by the value of the control range and the thus ascertained product determines the magnitude of the control signal (S) used during the retardation phase.
2. Method according to claim 1, characterised thereby, that a signal, which represents the setting of the main piston (32 or 32') and is preferably derived at a spring (37 or 37') coupled to the piston rod (33 or 33'), serves as restoring signal.
3. Method according to claim 1, characterised thereby, that a control deviation (CO) and a preliminary control signal (SO) are added to the product determining the control signal, wherein CO is found according to the relationship CO = S2 - SO - CS and wherein S2 is the second value of the control signal, SO is the preliminary control signal and CS is the control range and the sum thus ascertained represents the control signal (S) used during the retardation phase.
4. Method according to one of the preceding claims, characterised thereby, that the hysteresis value (H) is ascertained during a learning travel, during which the control signal (S) is increased until the speed reaches a preset value, the intensity of the control signal (S) is measured and stored on reaching the preset value, the control signal (S) is thereafter increased further and after a while decreased again until the preset value of the speed is reached again, the intensity of the control signal (S) is measured once again and a difference, which represents the hysteresis value (H), is formed from the two measured values.
5. Method according to claim 3, characterised thereby, that the preliminary control signal (SO) is ascertained during a learning travel, during which the coil of the regulating valve arrangement (13) is acted on by a control signal (S) rising in steps until the cage (1) starts off and wherein the control signal ascertained in that case is reduced by a constant value and stored as preliminary control signal (SO).
6. Method according to one of the preceding claims, characterised thereby, that a limit control signal (SL) is ascertained during a learning travel, during which the coil of the regulating valve arrangement (13) is acted on by a control signal (S) rising in steps until the speed of the cage (1) no longer rises.
7. Method according to one of the claims 1 to 5, characterised thereby, that the cage (1) is driven unregulated during the travel preceding the retardation phase, for which the speed is limited upwardly by the design of hydraulic components, such as for example a pump (45).
8. Equipment for the performance of the method according to the claims 1 to 7, with a regulating equipment (20), which controls a regulating valve arrangement (13), and with a measuring sensor (11) which stands in connection with the cage (1), wherein the regulating equipment (20) comprises at least one tacho-signal converter (22), wherein the measuring sensor (11) is connected to the input of the tacho-signal converter (22), and the regulating equipment (20) furthermore comprises a travel regulator (25), characterised thereby that the travel regulator at its input is connected with an output of the tacho-signal converter (22) delivering actual travel values (si) and at its output stands in connection with the regulating valve arrangement (13) during the retardation phase, that the travel regulator (25) comprises a table (26), in which associations of actual travel values (si) with percentage values (%S) of a control range are stored, that a multiplier (25.1) is provided, the one input of which is connected with the table (26), whilst the other input is acted on by the value of the control range , and the output of which forms the output of the travel regulator (25).
9. Equipment according to claim 8, characterised thereby, that a regulating valve arrangement (13) comprises a stroke force restoration preferably produced by means of a compression spring (37, 37').
10. Equipment according to claim 8, characterised by a regulating equipment (20) with a digital travel regulator (25).

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