Method for the positionally accurate receiving and depositing of a container using a gantry stacker and gantry stacker for this purpose

Abstract

A gantry stacker having a spreader for containers and including a locating system arranged on the gantry stacker that determines a position of the gantry stacker. To permit a more precise receiving or depositing of containers in a predefined position in a container terminal, sensors are arranged on the gantry stacker, with the sensors and the locating system being connected to a control unit, and the control unit determines a position of the spreader, of a container to be received or of a deposit site from the position of the gantry stacker using the signals from the sensors.

Claims

1. A gantry lift stacker comprising a straddle carrier having a spreader for containers and having a front first gantry frame part and a rear second gantry frame part which each have two vertical gantry supports extending with their respective longitudinal axis in parallel with the lifting and lowering direction, wherein the spreader is guided on the gantry supports of the gantry lift stacker during lifting and lowering and a lifting device for the spreader is attached to a gantry frame of the gantry lift stacker in a stationary manner, and having a locating system arranged on the gantry lift stacker, said locating system determining a position of the gantry lift stacker, wherein the locating system determines the position of the gantry lift stacker in relation to a point defined on a machine platform of the gantry lift stacker, wherein sensors are arranged on the gantry lift stacker, and wherein the sensors and the locating system are connected to a control unit, and wherein the control unit determines, from the position of the gantry lift stacker, using the signals from the sensors, a position of the spreader, of a container to be picked up or of a set-down location, and wherein the sensors arranged on the gantry lift stacker comprise at least one sensor for determining an inclination of the gantry lift stacker and at least one sensor for determining a relative position of the spreader on the gantry lift stacker, and wherein the relative position relates to the point defined on the machine platform for determining the position of the gantry lift stacker and includes a distance, measured in the lifting and lowering direction, of the spreader relative to the point defined on the machine platform for determining the position of the gantry lift stacker.

2. The gantry lift stacker as claimed in claim 1, wherein the position of the gantry lift stacker differs from the position of the spreader, of a container to be picked up or of a set-down location for containers.

3. The gantry lift stacker as claimed in claim 1, wherein the locating system comprises a receiver and at least this receiver is arranged on the machine platform.

4. The gantry lift stacker as claimed in claim 3, wherein the locating system is based on radio, radar, GNSS, GPS or laser technology.

5. The gantry lift stacker as claimed in claim 1, wherein arranged on the gantry lift stacker as one of the sensors is a sensor for determining a relative position of the spreader on the gantry lift stacker, via which a lifting height of the spreader relative to the position of the gantry lift stacker can be determined and is determined.

6. The gantry lift stacker as claimed in claim 5, wherein the sensor for determining a relative position of the spreader on the gantry lift stacker is attached to the lower side of the machine platform facing the spreader.

7. The gantry lift stacker as claimed in claim 6, wherein the sensor for determining a relative position of the spreader on the gantry lift stacker comprises at least one camera and/or at least one laser scanner which is directed towards a target mark applied to the center of the spreader.

8. The gantry lift stacker as claimed in claim 7, wherein the sensor for determining an inclination of the gantry lift stacker is an inclination sensor for determining a roll angle of the gantry lift stacker.

9. The gantry lift stacker as claimed in claim 8, wherein the sensor for determining an inclination of the gantry lift stacker is an inclination sensor for determining a pitch angle of the gantry lift stacker.

10. The gantry lift stacker as claimed in claim 9, wherein the control unit is electrically connected to the sensors and the locating system and exchanges data therewith.

11. The gantry lift stacker as claimed in claim 10, wherein the signals from the sensors and from the locating system are processed in the control unit for determining the position of the spreader, of a container to be picked up or of a set-down location for containers, and the position is forwarded to the travel drives, the lifting drives and/or a driver of the gantry lift stacker as navigational data.

12. The gantry lift stacker as claimed in claim 11, wherein the sensor for determining an inclination of the gantry lift stacker is an inclination sensor for determining a roll angle of the gantry lift stacker.

13. The gantry lift stacker as claimed in claim 1, wherein the sensor for determining an inclination of the gantry lift stacker is an inclination sensor for determining a pitch angle of the gantry lift stacker.

14. The gantry lift stacker as claimed in claim 1, wherein the control unit is electrically connected to the sensors and the locating system and exchanges data therewith.

15. The gantry lift stacker as claimed in claim 1, wherein the locating system is based on radio, radar, GNSS, GPS or laser technology.

16. The gantry lift stacker as claimed in claim 3, wherein arranged on the gantry lift stacker as one of the sensors is a sensor for determining a relative position of the spreader on the gantry lift stacker, via which a lifting height of the spreader relative to the position of the gantry lift stacker can be determined and is determined.

17. The gantry lift stacker as claimed in claim 2, wherein the locating system comprises a receiver and at least this receiver is arranged on the machine platform.

18. An arrangement of a gantry lift stacker, said arrangement comprising a storage area on a ground surface and of a gantry lift stacker as claimed in claim 1.

19. A method for a gantry lift stacker for determining the position of a spreader, of a container to be picked up or of a set-down location for containers for positioning containers by a gantry lift stacker comprising a straddle carrier as claimed in claim 1, said method comprising: determining positional data of the gantry lift stacker via the locating system arranged on the gantry lift stacker; and determining a position of the spreader, of the container to be picked up or of the set-down location from the positional data of the gantry lift stacker with the aid of the control unit and using data from the sensors arranged on the gantry lift stacker.

20. The method as claimed in claim 19, wherein in order to determine a relative position of the spreader on the gantry lift stacker by means of a sensor arranged on the gantry lift stacker, a lifting height of the spreader relative to the position of the gantry lift stacker is determined and is processed by the control unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a front view of a gantry lift stacker;

(2) FIG. 2 shows a side view of a gantry lift stacker;

(3) FIG. 3 shows a gantry lift stacker of FIG. 1 on inclined ground;

(4) FIG. 4 shows a gantry lift stacker of FIG. 2 on inclined ground; and

(5) FIG. 5 shows a block diagram with a control unit of the gantry lift stacker.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) FIG. 1 illustrates a front view of a gantry lift stacker, also known as a straddle carrier, designated by the reference numeral 1. The gantry lift stacker 1 substantially comprises a downwardly-open U-shaped gantry frame 2, a load picking-up means in the form of a so-called spreader 3 and two travel supports 4. The gantry frame 2 can be theoretically divided, as seen in a direction of travel F of the gantry lift stacker 1, into a front first gantry frame part and a rear second gantry frame part. Each gantry frame part has two vertical gantry supports 2a extending with their respective longitudinal axis in parallel with the lifting and lowering direction S. “Vertical” relates in this case to the situation shown in FIG. 1, in which the gantry lift stacker 1 is located on ideally flat and horizontally extending ground 11. The two gantry frame parts are connected to each other at their upper ends via a horizontal and frame-like machine platform 2b. The two left and right gantry supports 2a as seen in the direction of travel F are supported at their lower ends on the two travel supports 4. In a typical manner, the gantry lift stacker 1 with this design can travel over a container 9 or, depending upon the structural height, over a plurality of containers 9 stacked one on top of another, can pick up this container 9 or the uppermost container 9 with its spreader 3, can move the picked-up container 9 to a target location and at that location can set down the container on the ground 11, on an already set down container 9 or on a stack of containers. In this case, the containers 9 are typically arranged in rows and are oriented within the respective row each with their longitudinal direction in the longitudinal direction of the row. The spreader 3 is provided in each of its four corners with a so-called twist lock 3a in a typical manner in order to connect the containers 9 to the spreader 3 for the transport process with low tolerance. In so-called twin lift spreaders, eight twist locks 3a are accordingly provided in order to be able to pick up two short 20 foot containers 9 together one behind the other as seen in the direction of travel F by a spreader 3. The spreader 3 can be lifted and lowered vertically along the vertical gantry supports 2a of the gantry frame 2 in a lifting/lowering direction S. During lifting and lowering, the spreader 3 is guided on the gantry supports 2a such that in particular swinging of the spreader 3 relative to the longitudinal axis of the gantry supports 2a is minimised. The lifting device provided for lifting and lowering the spreader 3 is arranged on the gantry lift stacker 1 to be stationary in terms of the above definition.

(7) In order to be able to determine a current position of the gantry lift stacker 1 e.g. in the area of a port terminal, a locating system 5—also known under the designation Position Detection System (PDS)—is located on the machine platform 2b for locating the gantry lift stacker 1 and includes at least one locating system, alternatively two independent locating systems. The locating system can be based e.g. on radio, radar, GNSS, GPS or laser technology. The determined position of the gantry lift stacker 1 in terms of indicating the length and width or x and y coordinates in a local Cartesian coordinate system is placed in relation to the known point of attachment to the machine platform 2b in order thus to obtain a precise position of the gantry lift stacker 1 or the boundaries of the gantry lift stacker 1 as seen in plan view. The boundaries are formed in particular by outer contours of the gantry supports 2a. Since the attachment point of the locating system 5 is located at the height of the machine platform 2b, the positional data also relate to this height and not to the height of the travel supports 4, the respective height of a set-down or pick-up location for a container 9 or the ground 11 on which the gantry lift stacker 1 moves. Typically, the locating system 5 is also used in parallel for navigating the gantry lift stacker 1. In the context of the present invention, the locating system 5 is—in the sense of a receiver part of the locating system 5 receiving the positional data—i.e. for example an antenna of the locating system 5 because this generates the relevant reference of the positional data to the gantry lift stacker 1. The positional data received from the locating system 5 can then also be processed locally, separate from the receiver of the locating system 5.

(8) In order to be able to also relate the positional data—determined by means of the locating system 5 and related to the height of the machine platform 2b—with a high level of precision to other components of the gantry lift stacker 1, in particular beneath the machine platform 2b, the knowledge of a possible inclination of the gantry lift stacker 1 in and opposite to the direction of travel F in terms of a pitch angle N and, transverse thereto, in terms of a roll angle W is necessary. In order to determine a current inclination of the gantry lift stacker 1 starting from a vertical and thus on uneven or non-horizontal ground 11, at least one front or rear first inclination sensor 6a is provided on a front or rear side of the machine platform 2b pointing in or opposite the direction of travel F and at least one lateral second inclination sensor 6b is provided on a lateral side of the machine platform 2b pointing transverse to the direction of travel F, in order to be able to detect the pitch angle N and the roll angle W with a high level of precision (see also FIG. 2). In this context, uneven or non-horizontal ground 11 is understood to mean ground 11 on which the gantry lift stacker 1, in particular with the longitudinal axes of its gantry supports 2a, is or is moving not vertically but inclined with respect thereto. Basically, other points of attachment for the front first inclination sensor 6a and the lateral second inclination sensor 6b on the gantry lift stacker 1 and also combined inclination sensors for pitch angle N and roll angle W or the measurement thereof and redundant designs thereof are feasible. The knowledge of the pitch angle N and the roll angle W is important for precise positioning of the containers 9 and precisely approaching set-down containers 9 or an empty set-down location 15 on the ground 11 and will be of even greater importance as gantry lift stackers 1 become ever taller.

(9) In addition to the positional data of the locating system 5, the roll angle W and the pitch angle N, a current relative position of the spreader 3 on and thus in relation to the gantry lift stacker 1 should still be determined to determine a current position of the spreader 3, in particular in the form of absolute positional data of the spreader 3 which are as precise as possible. The respective position of the spreader 3 can then be used, as described below, to also simply determine the corresponding position of a transported container 9 picked up by the spreader 3.

(10) The relative position of the spreader 3 thus relates in the above sense in particular to the gantry frame 2 or the point relevant for determining the position of the gantry lift stacker 1, which point is defined e.g. by the locating system 5 on the machine platform 2b. Such a current relative position of the spreader 3 can be, in terms of a distance, the current lifting height of the spreader 3 relative to the gantry lift stacker 1 or relative to the locating system 5 on the machine platform 2b of the gantry frame 2 and/or can contain or be based on this height. The spreader 3 is typically fixedly connected to the container 9 via twist locks 3a. Depending upon whether the position of the container 9 is intended to relate to the upper side or lower side thereof, knowledge of the height h of the container 9 is also necessary, said height either being normed or being made available via a store management computer. A further sensor, not described, can also be used for this purpose.

(11) In order to determine the height and thus the current lifting height H of the spreader 3 as its relative position on the gantry lift stacker 1 or as part of, or the basis for, the position calculation, a sensor 7 is provided on the lower side of the machine platform 2b facing the spreader 3, via which sensor the distance between the machine platform 2b, in particular the locating system 5 at that location, and the spreader 3 can be determined. The distance relates to the lifting and lowering direction S in parallel with the longitudinal axes of the gantry supports 2a. A detailed and in particular three-dimensional relative position determination of the spreader 3 in relation to the gantry frame 2 or the machine platform 2b can be effected by means of the sensor 7. The sensor 7 can be formed as a camera or as a laser scanner which is directed towards a target mark 7a. In a corresponding manner, the target mark 7a is located centrally on the upper side of the spreader 3 facing the sensor 7.

(12) It is hereby possible on the whole, when lifting or lowering the spreader 3 vertically or in an inclined manner along the vertical or inclined gantry supports 2a of the gantry frame 2 in the lifting/lowering direction S, which is substantially in parallel with the longitudinal axis of the gantry supports 2a, to correspondingly correct and thus optimise—in addition to the current position of the gantry lift stacker 1 which relates to a height of the machine platform 2b and the location system 5 at that location—these positional data via the now known roll angle W, pitch angle N and lifting height H or distance of the spreader 3 and the height h of the container 9 for the container 9 to be approached and to be picked up, the empty set-down location 15 to be approached or a container 9 picked up by the spreader 3. Therefore, the current position of the spreader 3 and of a possibly picked up container 9 or of an empty set-down location 15 to be approached or of an already set down container 9 to be approached and to be picked up can be determined with maximised or maximum precision and the container 9 can be lowered or picked up with a high level of precision, in particular in a fully automatic manner.

(13) FIG. 2 shows a side view of the gantry lift stacker 1 of FIG. 1. The locating system 5 is arranged centrally on an upper side of the machine platform 2b of the gantry lift stacker 1. The sensor 7 can be seen on the lower side of the machine platform 2b and the target mark 7a can be seen on the upper side of the spreader 3. The travel supports 4, on which the travel drives 10 having rubber-tyred and pneumatic wheels and schematically illustrated in FIG. 5 are arranged, are located at each of the lower ends of the gantry supports 2a. In a typical manner, the gantry lift stacker 1 with this design can travel over a container 9 or, depending upon the structural height, over a plurality of containers 9 stacked one on top of another, can pick up this container with its spreader 3 via twist locks 3a in its four corners, can move the picked-up container to a target location and at that location can set down the container on the ground 11, on an already set down container 9 or on a stack of containers. It is obvious that, instead of the combination of sensor 7 and target mark 7a, other sensors can also be used in order to determine the relative position, and in this context as a distance, the lifting height H of the spreader 3.

(14) FIG. 3 shows a front view of the gantry lift stacker 1 of FIG. 1 standing on the ground 11. The ground 11, as seen in the direction of travel F, rises from a notional horizontal plane 12 transverse to the direction of travel F so that a gantry lift stacker 1 standing or moving on the ground 11 is inclined away from a vertical position towards the right by a roll angle W. In this regard, the roll angle W is formed between the vertical 13 and the lateral boundary of a gantry support 2a, wherein the boundary is formed in particular by an outer contour of the gantry supports 2a extending in parallel with the longitudinal axis of the gantry supports 2a. As a result, inclined positions or inclinations of the gantry lift stacker 1 to the right and left can be detected. A corresponding orientation of the gantry lift stacker 1 can of course also be present on uneven ground 11 in terms of a surface which is undulating or angled rather than entirely flat. In FIG. 3, the ground 11 is shown ideally as a flat and inherently inclined surface, i.e. a surface inclined with respect to the notional ideal flat and horizontal plane 12.

(15) FIG. 4 shows a side view of the gantry lift stacker 1 of FIG. 2 standing on the ground 11. The ground 11, as seen in the direction of travel F, decreases from a notional horizontal plane 12 in the direction of travel F so that a gantry lift stacker 1 standing or moving on the ground 11 is inclined forwards away from a vertical position in the direction of travel F by a pitch angle N. In this regard, the pitch angle N is formed between the vertical 13 and the rear boundary of a gantry support 2a, wherein the boundary is formed in particular by an outer contour of the gantry supports 2a extending in parallel with the longitudinal axis of the gantry supports 2a. As a result, inclined positions or inclinations of the gantry lift stacker 1 to the front and rear can be detected. A corresponding orientation of the gantry lift stacker 1 can of course also be present on uneven ground 11 in terms of a surface which is undulating or angled rather than entirely flat. In FIG. 4 also, the ground 11 is shown ideally as a flat and inherently inclined surface, i.e. a surface inclined with respect to the notional ideal flat and horizontal plane 12.

(16) The mode of operation of the invention will be described in more detail hereinafter with the aid of FIG. 5. FIG. 5 illustrates a block diagram which shows the individual sensors 6a, 6b, 7 which are used for determining the precise position of the spreader 3 or of the container 9 picked up by the spreader 3, and the locating system 5 which are electrically connected to a central control unit 8 and exchange data therewith. This control unit 8 processes the location coordinates obtained by the locating system 5 which are indicated in a typical manner in degrees, minutes and seconds—°, ′, ″—the relative position of the spreader, obtained by the sensor 7 and the target mark 7a, with the lifting height H, determined as a distance for this purpose, the pitch angle N which is determined and transmitted by the corresponding inclination sensor 6a and the roll angle W which is determined and transmitted by the corresponding inclination sensor 6b in order to convert the position, known by the locating system 5, of the gantry lift stacker 1 in the region of the machine platform 2b to the absolute position of the spreader 3. Using the thus obtained absolute position of the spreader 3, the travel drives 10 and lifting drives 14 of the gantry lift stacker 1 are actuated by the control unit 8, or a driver of the gantry lift stacker 1 is provided with corresponding navigational data. Therefore, it is possible for the gantry lift stacker 1 to set down or pick up a container 9 at a precise position on or from the predetermined target position.

(17) The control unit 8 can be formed as a separate unit as in the exemplified embodiment of FIG. 5 or can also be integrated into a vehicle controller of the gantry lift stacker 1.

(18) In order to pick up a container 9, the gantry lift stacker 1 is moved, using the travel drives 10, over a container 9 to be picked up. This occurs e.g. by manually controlling the travel drives 10, in so doing the gantry lift stacker 1 is steered to the desired position e.g. manually by a driver and alternatively supported by a navigation system which uses the positional data of the spreader 3 of the control unit 8. The desired position is here the position of the spreader 3 at the lifting height H of the planned pick-up, i.e. with a corresponding distance of the spreader 3 from the machine platform 2b and the relevant point defined at that location for determining the position of the gantry lift stacker 1. Alternatively or in addition, automatic control of the gantry lift stacker 1 and thus of the travel drives 10 and the lifting drives 14 supported by the positional data of the spreader 3 of the control unit 8 is also feasible. In this way, in addition to the displacement or inclination of the gantry lift stacker 1 from vertical, also design flexibilities of the gantry lift stacker 1, in particular the gantry supports 2a, or deviations in the position of the spreader 3 caused by present tolerances, which also depend upon the loading state of the gantry lift stacker 1, can advantageously be compensated for as a whole. The position of the spreader 3 or of the container 9 is thus determined with maximum precision. The container 9 is then picked up by the spreader 3 and is connected to the spreader 3 by means of a typical twist lock with low tolerance. The position of the container 9 is thus sufficiently precisely defined by the connection to the spreader 3. The container 9 is then lifted by the spreader 3.

(19) The gantry lift stacker 1 is then moved to a desired position, e.g. to the desired set-down area or set-down location 15 of the container 9 and the spreader 3 is lowered in order to set down the container 9. For the case where the container 9 is picked up, the position of the spreader 3 or of the container 9 is determined by the control unit 8 in order then to set down the container 9 at the intended set-down area or set-down location 15 with maximum precision.

(20) As a result, a more precise arrangement of containers 9 within a container row or within the container terminal is rendered possible and the thus fewer deviations from an intended set-down location 15 improves the utilisation of space within a container terminal.