EP2383218A2 - Method for fetching a crane - Google Patents

Abstract

The method involves emitting electromagnetic waves between a wireless manual control unit (12) for the crane control and a crane (1). The manual control unit is assigned to the cranes. The electromagnetic waves are received with a receiving unit (8) in the crane. The absolute position of the manual control unit is determined. The absolute position of the crane is determined. The Wireless local area network-access-points are used as radio beacon.

Description

The invention relates to a method for traveling along a stationary track cranes with which the operator can pick up a crane at the touch of a button to him.

Such cranes usually move on fixed rails in halls or open factory areas. Very often, these electric cranes are used only sporadically, with changing loads being picked up from different positions. For this purpose, the operating procedure is usually such that the operator first 'fills' the crane, i. e.g. The crane is placed over the load to be moved by means of moving the trolley via the functions 'crane travel' and 'trolley travel', ie, it takes place or minimizes the distance.

Since this process is usually repeated very frequently with changing positions of the loads to be moved and can take a lot of time in cranes with a large span or large crane run lengths, it seems sensible to simplify and automate this process.

The idea is to determine the position of the operator via the operating handpiece (or remote control) relative to the current position of the crane. Subsequently, a suitable control of the crane can be done to make any necessary change of position automatically at the touch of a button.

From the DE 42 04 658 A1 is a remote control for conveyors, in particular materials handling equipment such as running cranes with a hand control device, known, in which an electromagnetic wave transmitter is included, and provided in the running crane receiver unit, in which a sensor for these electromagnetic waves is included, said Hand control unit is further provided with an ultrasonic transmitter and the receiving unit is provided with an ultrasonic sensor and computing means for determining the transit time differences between an infrared signal and an ultrasonic signal.

With this system, it should be possible to "call" the corresponding conveyor to the location within a workshop where it is needed next.

For this purpose, the remote control comprises two transmitters, namely an infrared and an ultrasonic transmitter to emit a signal simultaneously after actuation of a switch, which is received by means of appropriate receivers on the conveyor and then evaluated in the conveyor in a computer. The runtime difference between the two signals is determined and used for distance calculation (see column 2, lines 23 - 32).

However, this system has problems especially in spatially difficult situations to run accurate, since in particular the ultrasonic waves used tend to multiple reflections, etc. and thus differ the transit times and multiple signals are superimposed on the receiver. It is also technically complicated to provide two transmitters in the remote control at the same time. Also goes with such "time of flight" methods, the need for accurate clocks or their adjustment accompanied.

In contrast, the object of the present invention therefore is to provide a method for cranes, with which the operator can pick up the crane at the touch of a button and which is technically easy to implement and still delivers reliable results.

This object is achieved by the method given in claim 1.

As is the case with the prior art, the method for cranes traveling along a stationary track, with which the operator can pick up a crane at the touch of a button, comprises the steps of emitting electromagnetic waves between a wireless crane control hand control device and the crane and receiving the crane electromagnetic waves by means of a receiver unit.

• Bestimmen der absoluten Position des Handsteuergeräts;
• Bestimmen der absoluten Position des Krans;
• Berechnen von Fahrbefehlen zur Minimierung des Abstands des Krans zum Handsteuergerät, um den Kran entlang seines ortsfesten Fahrwegs zu verfahren, aus der absoluten Position des Handsteuergeräts und der absoluten Position des Krans sowie
• Heranholen des Krans durch Verfahren entlang seines ortsfesten Fahrwegs gemäß der berechneten Fahrbefehle.

In contrast to the prior art, however, the following steps are carried out:

• Determining the absolute position of the hand controller;
• Determining the absolute position of the crane;
• Calculating travel commands to minimize the distance of the crane to the hand control device to move the crane along its fixed travel path, from the absolute position of the hand control device and the absolute position of the crane as well
• Picking up the crane by moving along its fixed track in accordance with the calculated travel commands.

This function of the crane is also referred to as a "follow-me" function, as the crane follows, so to speak, the operator.

For this purpose, the crane is moved as close as possible to the operator. In order to trigger this "behavior" of the crane, the operator actuates a corresponding button on the "wireless" manual control unit, whereupon a radio signal is emitted by the manual control unit and received in the crane. The actuation of the switch in the manual control unit thus triggers a transmission of a pick-up signal and its reception in the receiver unit from picking up.

Subsequently, both the absolute position of the manual control unit and the absolute position of the crane are determined. Travel commands for the crane can then be calculated from these positions in order to move them to minimize the distance. The calculation of the travel commands, ie the evaluation of the absolute positions, can take place in a controller in the crane or in a controller in the manual control unit. Depending on where the calculation is carried out, the absolute position information must either be transmitted from the crane to the manual control device or vice versa; i.e. the hand control device or the crane in each case transmit its specific absolute position to the crane or the manual control device.

The method may be semi-automatic or (fully) -automatic, so that the fetching distance is minimized by semi-automatically after a switch is operated in the manual control unit, or the fetching distance is minimized automatically after a switch is operated in the manual control unit ,

In the first case, the crane will only move as long as the switch is operated. This has the advantage of a "dead man" function, which may be desired for reasons of safety at work. In the second case, the switch is actuated only once and the crane is moved automatically until the desired position is reached with a minimum distance.

In principle, there are two basic variants for carrying out the method.

In the first variant, both the hand control device and the crane each comprise a receiver unit and an evaluation unit to receive signals from at least two radio beacons in order to determine from the signals the respective relative position to the radio beacons and from there their absolute position ,

In the second variant, both the hand control device and the crane each comprise a receiver unit with two antennas and an evaluation unit to receive two signals from at least one radio beacon via the respective antennas to from the signals the respective relative position to the beacon and to determine their absolute position from this.

It is understood that both of the above variants are combinable, i. e.g. Evaluation of signals from two wireless beacons by the hand control device and evaluation of signals from a radio beacon via two antennas in the crane, etc.

In the present case, radio beacons are understood to mean devices which emit a radio signal via which the position of the manual control device or of the crane can be determined by means of direction determination, time measurement or strength of the radiated signals. This determination can be made in principle by known methods.

Wireless beacons can be WLAN access points, Dect base stations or dedicated devices that may be networked and time-synchronized.

The use of signal strength, e.g. in the form of an RSSI (Received Signal Strength Indication) signal, has the advantage that modern transceivers, which are commonly used, already have the ability to determine the signal strength. Thus, the implementation of the method is simple and the corresponding equipment and system can be set up and adapted inexpensively and quickly.

The Received Signal Strength Indication (RSSI) provides an indicator of the Reception field strength of wireless communication applications. The RRSI indicator is needed eg by mobile phones and other systems dependent on radio communication in order to find a channel that is usable for the communication. If the signal strength required for successful communication falls short of the currently used channel, the RSSI value can be used to switch to a better (stronger) channel if necessary.

A further increase in accuracy and reliability can be obtained if either multiple receiver units or antennas and / or multiple transmitters are used and / or a signal strength method is combined with a signal transit time method.

• Fig. 1 eine schematische Ansicht eines mit einer "Follow-me"-Funktion ausgerüsteten Hallenkrans beim Heranholen gezeigt ist und
• Fig. 2 eine schematischer Ablauf der in Figur 1 durchgeführten Schritte im Rahmen des Verfahrens zum Heranholen des Krans.

Further details, features and advantages of the invention will become apparent from the following description of an embodiment with reference to the drawing, in which

• Fig. 1 a schematic view of a equipped with a "follow-me" function hall crane is shown in picking up and
• Fig. 2 a schematic sequence of in FIG. 1 carried out in the context of the crane lifting method.

In the FIG. 1 is shown as a whole with 1 designated hall crane. The hall crane 1 consists of a crane girder 5, which can be moved on an existing under a hall roof crane runway 2. On this crane girder 5, one or more movable trolleys 3 are arranged. In the present example, only one trolley 3 is shown.

On this trolley 3, a hoist (not shown) is provided for lifting and lowering the loads. In the present case, only the load hook 7 of the hoist for the attachment of the load is indicated.

All three directions of movement, so the movement of the crane girder 5, trolley 3 and the hoist, by the operator 11 by means of a wireless Hand control unit 12 controlled, which allows a method of the trolley 3 along the crane girder 5 (X-direction) and the movement of the crane girder 5 along the line extending in the viewing direction crane track 2 (Y-direction) and lowering and lifting the load hook 7 on the in the trolley 3 integrated (not shown) hoist.

The crane 1 further comprises in the trolley 3 two receivers 8 and 9 and a controller 10. The receiver 9 receives signals S1, S2 from two networked and time-synchronized radio beacons B1, B2 in order to determine the absolute position from the signal strengths and signal propagation time differences of the crane or of the trolley 3 and of the crane girder 5 in the control 10.

The receiver 8 is used to receive control signals and information from the handheld terminal 12.

The handheld terminal 12 is equipped with a corresponding transmitting unit 13 to trigger the pickup by emitting a corresponding signal S upon actuation of a switch 14.

For safety reasons, the 'follow-me' function can only be started when the load hook 7 is in a safe position (evaluation of a relay contact 'highest hook position').

The actuation of the switch 14 in the handheld terminal 12 thus triggers a sending out of the pick-up signal S and its reception in the receiver unit 8 and thus minimizing the distance of the trolley 3 to the operator 11 by moving the trolley 3 and the crane girder 5.

The handheld terminal 12 further includes a receiver 15 and a controller 16 to receive signals S1, S2 from the two networked and time-synchronized radio beacons B1, B2 and to determine the absolute position of the handheld terminal 12 from the signal strengths and signal propagation time differences. Subsequently, this position is transmitted via the transmitting unit 13 to the crane, which receives the corresponding signal with its receiver 8.

In addition to the own absolute position determined by the crane, the crane now also has the absolute position of the handheld terminal 12, so that the controller 10 can calculate the travel commands necessary for distance minimization and control the trolley 3 or the crane girder 5 correspondingly to the dashed marked position in FIG FIG. 1 to approach.

The flow of the procedure is described below using the flowchart in FIG FIG. 2 explained in more detail.

The operator 11 actuates the pickup key 14 (step 100), which triggers transmission of the signal S from the transmitting unit 13 of the handheld terminal 12 (step 101).

This signal S is received by the receiver 8 in the trolley 3 (step 102) and triggers in the control the "Follow-me" mode (step 103).

In the subsequent step 104 is then checked for safety reasons by evaluating a relay contact, whether the hooks 7 is in a safe position, the highest hook position.

If this is answered in the negative, the "Follow-me" mode is terminated (step 105) or the pick-up is not carried out and if necessary an optical and / or acoustic error signal is output.

Should the load hook 7 be in the required secure position, its respective absolute position will now be determined in parallel in the trolley 3 or the handheld terminal 12 (step 106). For this purpose, the trolley 3 and the handheld terminal 12 receive signals S1, S2 from the two networked and time-synchronized radio beacons B1, B2 in the receivers 8 and 15. Based on the time differences and signal strengths are from the respective controllers 10 and 16 determines the absolute positions.

Subsequently, the handheld terminal 12 transmits via its control channel from the transmitting unit 13, the information (absolute position) to the trolley 3, which receives this information in the receiver 8 and for evaluation to the controller 10 forwards (step 107).

The controller 10 now calculates, using the two absolute positions of the trolley 3 and the manual control unit 12, the travel commands necessary for distance minimization in the X and Y directions (step 108).

Subsequently, the controller 10 controls the trolley 3 and the crane girder 5 in accordance with the calculated running commands to minimize the distance to the operator 11 by appropriately moving the trolley 3 and the crane girder 5, respectively (step 109).

LIST OF REFERENCE NUMBERS

1

Hallenkran

2

crane runway

3

trolley

5

crane carrier

7

load hook

8th

receiver

9

receiver

10

control

11

operator

12

Manual control unit

13

transmission unit

14

Heranholtaste

15

receiver

16

control

B1, B2

bake

S, S1, S2

signals

X

direction

Y

direction

Claims (9)

A method for cranes (1, 3, 5) movable along a stationary track (2) by which the operator (11) can pick up a crane (1, 3, 5) at the push of a button (14), comprising the steps: Transmitting electromagnetic waves (S) between a wireless hand control device (12) for the crane control and the crane (1, 3, 5) assigned to the crane (1, 3, 5); - Receiving the electromagnetic waves (S) by means of a receiver unit (8) in the crane (1, 3, 5) for triggering the fetching; characterized by the further steps - determining the absolute position of the manual control device (12); - determining the absolute position of the crane (1, 3, 5); Calculating travel commands for minimizing the distance of the crane (1, 3, 5) to the manual control device (12) in order to move the crane (1, 3, 5) along its fixed travel path (2) from the absolute position of the manual control device ( 12) and the absolute position of the crane (1, 3, 5) and - picking up the crane (1, 3, 5) by moving along its fixed travel path (2) according to the calculated travel commands. 2. The method according to claim 1, characterized in that the catch-up semi-automatically or automatically after actuation of a switch (14) in the manual control unit (12). 3. The method according to claim 1 or 2, characterized in that the actuation of the switch (14) in the manual control unit (12) emitting a Heranholsignals (S) and receiving it in the receiver unit (8) triggers the pickup. 4. The method according to any one of the preceding claims, characterized in that both the manual control unit (12) and the crane (1, 3, 5) each comprise a receiver unit (15, 9) and an evaluation unit (16, 10) to signals (S1, S2) of at least two radio beacons (B1, B2) to receive to determine from the signals the respective relative position to the radio beacons and from this their absolute position. 5. The method according to any one of the preceding claims 1 to 3, characterized in that both the manual control unit (12) and the crane (1, 3, 5) each have a receiver unit (15, 9) with two antennas and an evaluation unit (16, 10) in order to receive two signals (S1, S2) from at least one radio beacon (B1) via the respective antennas in order to determine from the signals the respective relative position to the beacon and therefrom its absolute position. 6. The method according to claim 4 or 5, characterized in that the calculation of the travel commands in a controller (10) in the crane (1, 3, 5) or in a controller (16) takes place in the manual control unit (12). 7. The method according to claim 6, characterized in that the manual control device (12) or the crane (1, 3, 5) transmits its respective specific absolute position to the crane (1, 3, 5) or the manual control unit (12). 8. The method according to any one of the preceding claims, characterized in that signal strengths and / or signal propagation times are evaluated for determining position. 10. The method according to any one of the preceding claims, characterized in that as wireless beacons (B1, B2) Wlan access points or Dect base stations are used.

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