Method for moving a load with a crane in a collision-free manner

Abstract

A method for moving a load with a crane in a collision-free manner in a space having at least one obstacle includes providing a position of the obstacle, providing at least one safe state variable of the load, determining from the safe state variable a safety zone surrounding the load, and dynamically monitoring the safety zone in relation to the position of the obstacle.

Claims

1. A method for moving with a crane control system in automatic operation a load with a crane in a collision-free manner in a space having at least one obstacle, providing with a SIL (Safety Integrity Level) or PL (Performance Level) certified sensor a position of the at least one obstacle, determining with the SIL or PL certified sensor a height profile of the at least one obstacle, providing at least one safe state variable of the load, which includes a position of at least one movement axis, a velocity or an acceleration of the load, determining from the at least one safe state variable with a SIL or PL certified sensor system a safety zone surrounding the load, dynamically monitoring the safety zone in relation to the position of the obstacle, and sending with an independent, safe monitoring module, which implements a safety certification of the crane control system according to SIL or PL, a stop signal to the crane control system when the position of the obstacle is located in the safety zone surrounding the load.

2. The method of claim 1, further comprising acquiring a safe position of the obstacle using SIL or PL, certified sensors constructed for distance measurement.

3. The method of claim 1, wherein the at least one safe state variable of the load is determined from a safe state variable of at least one of a running gear, a lifting gear and a trolley of the crane.

4. The method of claim 1, further comprising determining from the height profile a safe trajectory for moving the load across the at least one obstacle, wherein along the safe trajectory is located outside the safety zone surrounding the load.

5. The method of claim 1, further comprising adapting a size of the safety zone to the safe state variable of the load.

6. The method of claim 1, wherein the safety zone is determined with a controller which comprises a safety program in a secure region.

7. The method of claim 6, further comprising sending with the safety program the stop signal to the crane control system.

8. The method of claim 1, wherein the safety zone is determined in real time.

9. The method of claim 1, wherein the safety zone is determined periodically in temporal intervals that depend on the safe state variable of the load.

10. The method of claim 1, wherein the safety zone is determined with an oscillation model.

11. The method of claim 1, further comprising executing the method independently of a movement of the load.

12. A controller comprising a safety program in a secure region, the controller configured to determine a safety zone surrounding a load that is moved with a crane in a collision-free manner in a space having at least one obstacle by providing with a SIL (Safety Integrity Level) or PL (Performance Level) certified sensor a position of the at least one obstacle, determining with the SIL or PL certified sensor height profile of the at obstacle, providing at least one safe state variable of the load, which includes a position of at least one movement axis, a velocity or an acceleration of the load, determining from the at least one safe state variable with a SIL or PL certified sensor system a safety zone surrounding the load, dynamically monitoring the safety zone in relation to the position of the obstacle, and sending with an independent, safe monitoring module a stop signal to the crane control system when the position of the obstacle is located in the safety zone surrounding the load.

13. A system having a crane for moving a load in a space having at least one obstacle, the system comprising an independent, safe monitoring module for collision detection between the load and the at least one obstacle and a controller comprising a safety program in a secure region, the controller configured to determine a safety zone surrounding a load that is moved with a crane in a collision-free manner in a space having at least one obstacle and implementing a safety certification of the system according to SIL (Safety Integrity Level) or PL (Performance Level), by providing with a SIL or PL certified sensor a position of the at least one obstacle, determining with the SIL or PL certified sensor a height profile of the at least one obstacle, providing at least one safe state variable of the load, which includes a position of at least one movement axis, a velocity or an acceleration of the load. determining from the at least one safe state variable with a SIL or PL certified sensor system a safety zone surrounding the load, dynamically monitoring with the independent, safe monitoring module the safety zone in relation to the position of the obstacle, and sending with the independent, safe monitoring module a stop signal to the crane control system when the position of the obstacle is located in the safety zone surrounding the load.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention will now be described and explained in greater detail making reference to the exemplary embodiments illustrated in the drawings.

(2) FIG. 1 is a perspective schematic representation of a crane,

(3) FIG. 2 is an enlarged schematic representation of a crane in the region of a load,

(4) FIG. 3 is a schematic representation of a collision-free movement of a load from a start point to a target point, and

(5) FIG. 4 is a flow diagram of a method for collision-free movement of a load.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(6) The exemplary embodiments set out in the following are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that are to be regarded as independent of one another and each also further develop the invention independently of one another and are thus also to be considered individually, or in a combination different from that shown, as a constituent of the invention. Furthermore, the embodiments described are also enhanceable with others of the previously described features of the invention.

(7) The same reference signs have the same meaning in the different figures.

(8) FIG. 1 shows a perspective view of a crane 2 which is configured, for example as a gantry crane. A load 4, for example, a container, which is fastened to a container handling frame 6, also called a spreader, is moved by means of a travelling carriage 8, also called a trolley, by means of a running gear 10 and/or by means of a lifting gear 12 along an, in particular, three-dimensionally configured trajectory 14. The movement of the load 4 by means of the crane 2 takes place, in particular, automatically. By means of at least one sensor 16 for distance measurement a safe position of an obstacle 18, in FIG. 1 a “container mountain” is acquired in that a height profile is created. Alternatively, a known position of the obstacle 18 is provided. In particular, a safe position of the obstacle 18 is determined by at least SIL or PL-certified sensor systems. At least SIL and/or PL-certified sensors 16 of this type for distance measuring operate, for example, with radar and/or laser methods. In particular, the sensors 16 for distance measuring are configured with redundancy. The safe position acquisition of the obstacle 18 takes place, in particular, dynamically in that, for example, the height profile is periodically updated. The obstacle 18 prevents the load 4 being transportable by a direct, that is, a straight-line route to its destination. Therefore, on the basis of the height profile, a trajectory 14, for example, a parabolic movement in order to overcome the obstacle 18, is calculated. A swaying of the load 4 while it is moved along the trajectory 14 is minimized by oscillation damping, also called sway control, in order to prevent collisions or damage to the load and/or to increase a load transporting efficiency.

(9) FIG. 2 shows an enlarged schematic representation of a crane 2 in the region of a load 4 which is moved over and beyond an obstacle 18. In order to ensure reliably a collision-free movement of the load 4, the crane 2 comprises an independent safe monitoring module for collision detection, to which a safe state variable of the load 4 is transmitted, wherein the safe state variable comprises a position, a velocity or an acceleration of the load 4. For example, a safe position of the load 4 is determined by means of a safe sensor system, certified in particular, at least in accordance with SIL and/or PL, on the trolley 8, on the running gear 10 and on the lifting gear 12, wherein a velocity and/or an acceleration of the load 4 are calculable directly from a change in the safe position.

(10) The independent, safe monitoring module calculates in real time in a safe controller, from at least one safe state variable, a safety zone 20 surrounding the load 4, for example, from a position and a velocity. For example, the safety zone 20 is periodically calculated in temporal intervals dependent upon the safe state variable of the load 4. A safe controller comprises a safety program in a secure region. The safety zone 20 is configured, as shown in FIG. 2, for example, spherical or ellipsoid. In particular, a size of the safety zone 20 is adapted to a safe state variable of the load 4, for example, to a velocity or an acceleration. For example, the volume of the safety zone 20 is enlarged if the velocity or the acceleration of the load 4 is increased. Optionally, an oscillation model is included in the calculation of the safety zone 20 in order to take account also, for example, of a swinging-out of the load 4 on an abrupt deceleration.

(11) The safe position acquisition of the obstacle 18 takes place as described in relation to FIG. 1. The independent, safe monitoring module dynamically monitors the safety zone 20 in relation to the position of the obstacle 18. For example, a stop signal is sent to a crane control system if the obstacle 18 is acquired in the safety zone 20 surrounding the load 4. The further configuration of the crane 2 in FIG. 2 corresponds to that of FIG. 1.

(12) FIG. 3 shows a schematic representation of a collision-free movement of a load 4 from a start point 22 to a target point 24, wherein the load movement takes place with the aid of a crane 2, in particular, automatically. By way of example, the load movement from a container ship 26 as the start point 22 to a heavy goods vehicle 28 as the target point 24 is shown, wherein the obstacle 18 which exists as a “container mountain” as described in relation to FIG. 1, is cleared in a parabolic movement along an, in particular, precalculated trajectory 14. In order to ensure a collision-free movement reliably, the crane 2 comprises an independent, safe monitoring module 19 for collision detection which, as described in relation to FIG. 2, calculates in a safe controller 19a in real time, the safety zone 20 surrounding the load 4. In particular, the size of the safety zone 20 that surrounds the load 4 is adapted, for example, to a velocity and/or an acceleration. The temporal change in the volume of the safety zone 20 represented, by way of example, as spherical, is shown schematically in FIG. 2 for a given obstacle 18, wherein the trajectory 14, as shown in FIG. 1 is calculated on the basis of the determined height profile of the obstacle 18. The further configuration of the crane 2 in FIG. 3, in particular of the independent safe monitoring module in FIG. 3 corresponds to that of FIG. 2.

(13) FIG. 4 shows a flow diagram of a method for collision-free movement of a load 4. The automated movement 28 of the load 4 takes place with a high level of reliability by means of sway control 30, geometrical calculation 32 of the trajectory 14, disturbance variable monitoring 34 and, in particular dynamic, object acquisition 36. The object acquisition 36, that is, the acquisition of the position of the obstacle 18 takes place as described in relation to FIG. 1, safely, in particular, on the basis of a height profile by at least SIL or PL-certified sensor systems.

(14) A safe state variable acquisition 38 of the load 4 takes place in parallel as described in relation to FIG. 2, for example, by means of a sensor system safety certified in accordance with SIL and/or PL, on the trolley 8, on the running gear 10 and on the lifting gear 12. An independent, safe monitoring module 40 carries out a safety zone calculation 42 on the basis of the safe state variable as determined. A dynamic space monitoring 44 takes place in that the safely acquired safety zone 20 is monitored in relation to the safely acquired position of the obstacle 18. A safe stop 46, for example, by sending a stop signal to a crane control system is initiated by the independent, safe monitoring module 40 when the obstacle 18 is detected in the safety zone 20 of the load 4.

(15) Summarizing, the invention relates to a method for collision-free movement of a load 4 with a crane 2 in a space having at least one obstacle 18. In order to achieve a safety level in the simplest possible manner, it is proposed that a position of the obstacle 18 is acquired, wherein at least one safe state variable of the load 4 is determined, wherein from the safe state variable, a safety zone 20 surrounding the load 4 is determined, wherein the safety zone 20 is dynamically monitored in relation to the position of the obstacle 18.