CONTROL UNIT AND METHOD FOR OPERATING A CONVEYING MEANS

Abstract

The invention relates to a method for operating conveyor means and to a control unit (10) for conveyor means, in particular hoisting gear, cranes, gantry cranes, container cranes or the like, the conveyor means comprising a drive unit (11) and a control unit for controlling the drive unit, a carriage of the conveyor means being moved along a rail (12) of the conveyor means by means of the drive unit, the control unit being controlled by means of a control device (13) of the control unit, a rotary encoder (16) of the control unit being connected to a shaft (18) of the drive unit or of a measuring wheel of the carriage and registering a rotation of the shaft, a rotation angle signal and/or a rotational speed signal being transmitted to the control device by means of an encoder device (17) of the rotary encoder in order to determine an assumed position of the carriage on the rail. At least one position signal is detected by means of a sensor apparatus (14) of a safety device of the control unit disposed on the carriage and the rail, a real position of the carriage on the rail being determined using the position signal by means of a safety apparatus (25) of the safety device, the assumed position being corrected according to the real position by means of the safety device.

Claims

1. A method for operating conveyor means (27), the conveyor means comprising a drive unit (11) and a control unit (10) for controlling the drive unit, a carriage (28) of the conveyor means being moved along a rail (12, 29, 49, 67) of the conveyor means by means of the drive unit, the control unit being controlled by means of a control device (13) of the control unit, a rotary encoder (16, 36, 56) of the control unit being connected to a shaft (18) of the drive unit or of a measuring wheel of the carriage and registering a rotation of the shaft, a rotation angle signal, a rotational speed signal or a position value being transmitted to the control device by means of an encoder device (17, 37, 52, 58) of the rotary encoder in order to determine an assumed position of the carriage on the rail, wherein at least one position signal is detected by means of a sensor apparatus (14, 40, 70) of a safety device (71) of the control unit, the sensor apparatus being disposed on the carriage and the rail, a real position of the carriage on the rail being determined by means of a safety apparatus (25, 38, 51, 59) of the safety device based on the position signal, the assumed position being corrected according to the real position by means of the safety device.

2. The method according to claim 1, wherein the safety apparatus (25, 38, 51, 59) corrects the rotation angle signal, the rotational speed signal or the position value according to the real position and transmits this information to the control device (13) in order to control the drive unit (11).

3. The method according to claim 1, wherein the rotary encoder (16, 36, 56) is connected to the shaft (18) of the drive unit (11), the safety apparatus (25, 38, 51, 59) determining the assumed position, comparing it to the real position and determining a slippage of the drive unit based on the comparison.

4. The method according to the preceding claim 1, wherein the safety apparatus (25, 38, 51, 59) processes the rotation angle signal or the rotational speed signal of the rotary encoder (16, 36, 56) and determines when a threshold of an acceleration is not met or is exceeded and detects a slippage of the drive unit (11) when a threshold is not met.

5. The method according to claim 1, wherein the rotary encoder (16, 36, 56) is connected to the shaft (18) of the measuring wheel, another rotary encoder of the safety device (71) being connected to the shaft of the drive unit (11), the safety device comparing the rotation angle signal or the rotational speed signal of the rotary encoder to a rotation angle signal, a rotational speed signal or a position value of the other rotary encoder and determining a slippage of the drive unit based on the comparison.

6. The method according to claim 3, wherein the safety device (71) limits a maximal threshold rotational speed to a reduced threshold rotational speed of the drive unit (11) when slippage occurs and transmits the reduced threshold rotational speed to the control device (13) in order to control the drive unit, the safety device clearing the maximal threshold rotational speed when the real position of the carriage (28) on the rail (12, 29, 49, 67) is determined.

7. The method according to claim 3, wherein the safety device (71) continuously determines the slippage or the real position of the carriage (28) on the rail (12, 29, 49, 67).

8. The method according to claim 3, wherein the safety device (71) determines a speed or constancy of the speed from the rotation angle signal, the rotational speed signal or the position value, the safety device determining the wear of the carriage (28).

9. The method according to claim 1, wherein the position signal is generated by means of at least one sensor (22, 31, 47, 50, 63) of the sensor device (14, 40, 70) disposed on the carriage (28) when passing markings (19, 30, 46, 48, 63) of the sensor apparatus disposed on the rail (12, 29, 49, 67).

10. The method according to claim 9, wherein the safety device (71) is calibrated via all markings (19, 30, 46, 48, 63) being passed with the sensor (22, 31, 47, 50, 63), the real positions of the markings being determined and being stored in the safety apparatus (25, 38, 51, 59).

11. The method according to claim 9, wherein the sensor apparatus (14, 40, 70) comprises at least two sensors (22, 31, 47, 50, 63) disposed on the carriage (28) and a plurality of markings (19, 30, 46, 48, 63) disposed along the rail (12, 29, 49, 67), passive RFID transponders (20, 21, 33, 42, 43) being used as markings and RFID transceivers (23, 34, 41) being used as sensors.

12. The method according to claim 11, wherein a position point (55) is defined halfway between an entry point (45, 54) and an exit point (44, 53) of a receiving area (41) of the RFID transponder (20, 21, 33, 42, 43) upon passage, the safety apparatus (25, 38, 51, 59) using the position point or the entry point and the exit point for determining the real position.

13. The method according to claim 9, wherein sensors (22, 31, 47, 50, 63) disposed on the carriage (28) at a relative distance LS and markings (19, 30, 46, 48, 63) disposed on the rail (12, 29, 49, 67) at a relative distance L are used, the following holding true: LS=L or LS>L, preferably LS=n*L, with n=1, 2, 3.

14. The method according to claim 9, wherein sensors (22, 31, 47, 50, 63) disposed on the carriage (28) at a relative distance LS and markings disposed on the rail (12, 29, 49, 67) at a relative distance L1 and L2 are used, the following holding true: LS=n*L1 and L1< >L2, preferably LS=L1 and L1<L2.

15. The method according to claim 9, wherein sensors (22, 31, 47, 50, 63) disposed on the carriage (28) at a relative distance LS and markings (19, 30, 46, 48, 63) disposed on the rail (12, 29, 49, 67) at a relative distance L are used, the following holding true: LS L or LS=9/10 L.

16. The method according to claim 1, wherein a switch signal of an end switch of the sensor apparatus (14, 40, 70) is detected and transmitted to the control device (13) by means of the safety apparatus (25, 38, 51, 59) in order to control the drive unit (11).

17. A control unit (10) for conveyor means, the conveyor means comprising a drive unit (11) and the control unit for controlling the drive unit, a carriage (28) of the conveyor means being movable along a rail (12, 29, 49, 67) of the conveyor means by means of the drive unit, the control unit comprising a control device (13) by means of which the drive unit is controllable, the control unit comprising a rotary encoder (16, 36, 56) which is connectable to a shaft (18) of the drive unit or of a measuring wheel of the carriage for registering a rotation of the shaft, the rotary encoder comprising an encoder device (17, 37, 52, 58) by means of which a rotation angle signal, a rotational speed signal or a position value is transmittable to the control device in order to determine an assumed position of the carriage on the rail, wherein the control unit has a safety device (71) having a sensor apparatus (14, 40, 70) positionable on the carriage and the rail, at last one position signal being detectable by means of the sensor apparatus, the safety device having a safety apparatus (25, 38, 51, 59) by means of which a real position of the carriage on the rail is determinable based on the position signal, the assumed position being correctable according to the real position by means of the safety device.

18. The control unit according to claim 17, wherein the rotary encoder (16, 36, 56) has the safety apparatus (25, 38, 51, 59).

19. The control unit according to claim 17, wherein the rotary encoder (16, 36, 56) has a field bus interface (61) or a switching output (60) for exceeding or not meeting a scaled output value capable of parametrization or dependent on position.

20. The control unit according to claim 17, wherein the rotary encoder (16, 36, 56) is an incremental encoder or an absolute encoder.

21. Conveyor means (27), in particular hoisting gear, cranes, gantry cranes, container cranes or the like, the conveyor means comprising a control unit (10) according to claim 17, at least one rail (12, 29, 49, 67), a carriage (28) movable along the rail and a drive unit (11) having an electric motor.

Description

[0033] FIG. 1 shows a schematic view of a configuration of a control unit;

[0034] FIG. 2 shows a sectional view of conveyor means;

[0035] FIG. 3a shows a spatial view of a signal of a marking along with sensors moved in relation thereto;

[0036] FIG. 3b shows another spatial view of the signal of the marking along with the sensors moved in relation thereto;

[0037] FIG. 4 shows a first embodiment of a possible relative arrangement of markings and sensors;

[0038] FIG. 5 shows a second embodiment of a relative arrangement of markings and sensors;

[0039] FIG. 6 shows a third embodiment of a relative arrangement of markings and sensors;

[0040] FIG. 7 shows a sectional view of conveyor means having a relative arrangement of markings and sensors;

[0041] FIG. 8 shows a schematic view of a safety device;

[0042] FIG. 9 shows a schematic view of a process sequence for operating conveyor means of a safety device.

[0043] FIG. 1 shows a control unit 10 in conjunction with a drive unit 11 and a rail 12 of conveyor means (not further illustrated). Control unit 10 comprises a control device 13, a sensor apparatus 14, a programming device 15 and a rotary encoder 16. Control device 13 can receive a rotation angle signal, a rotational speed signal and/or a position value of an encoder device 17 of rotary encoder 16. Rotary encoder 16 is coupled with drive unit 11 or alternatively a measuring wheel, which abuts against the rail 12, via a shaft 18. Drive unit 11 itself acts on rail 12 via a drive wheel (not illustrated) and thus drives a carriage of the conveyor means which is moveable along rail 12. Drive unit 11 can comprise an electric motor (not illustrated) and a transmission.

[0044] Sensor apparatus 14 has a plurality of markings 19 which are designed as RFID transponders 20, 21. Furthermore, sensor apparatus 14 has two sensors 22 which are designed as RFID transceivers. RFID transponders 20, 21 are provided with individual identifiers and are fastened to rail 12. Sensors 22 are disposed on the carriage (not shown) and are each connected to a safety apparatus 25 integrated in rotary encoder 16 via cables 24. RFID transceivers 23 each generate an electromagnetic field 26 via which RFID transponders 20, 21 can be detected and position signals can be obtained in each case.

[0045] When operating drive unit 11, rotary encoder 16 detects a rotation angle signal, a rotational speed signal and/or a position value via encoder device 17 and transfers them to control device 13. Furthermore, rotary encoder 16 and/or safety apparatus 25 receives a position signal from RFID transceiver 23 and RFID transponder 20, 21. Safety apparatus 25 process the rotation angle signal and/or the rotational speed signal and determines an assumed position of the carriage on rail 12. Furthermore, the position signal makes it possible to determine a real position of the carriage on the rail. Thus, real position information can stored in a storage medium of the safety apparatus 25 for RFID transponder 20, for example in a look-up table. Safety apparatus 25 compares the assumed position to the real position and determines possible slippage of drive unit 11, e.g., caused by a drive wheel overspinning on rail 12. If slippage is detected by safety apparatus 25 or if this slippage is outside of a tolerance area, safety apparatus 25 corrects the assumed position according to the real position. This correction can also take place by the rotation angle signal and/or the rotational speed signal transmitted to control device 13 being corrected or adjusted accordingly. Thus, it is overall possible to safely determine a precise position of the carriage on rail 12.

[0046] FIG. 2 shows a schematic view of conveyor means 27 having a carriage 28 and a rail 29. Markings 30 are applied to rail 29 and sensors 31 are applied to carriage 28. Carriage 28 is moveable along rail 29, as indicated by arrow 32. Markings 30 are RFID transponders 33 and sensors 31 are RFID transceivers 34. Carriage 28 is formed by a crane bridge 35. A rotary encoder 36 disposed on crane bridge 35 comprises an encoder device 37 and a safety apparatus 38. Safety apparatus 38 has a safety switch 39. Using encoder device 37, an absolute value of a movement of the crane bridge 35 on rail 39 is detected via a measuring wheel (not shown). Markings 30 are individualized and disposed on rail 39 at distances relative to each other, X.sub.m corresponding to 0.45 m. For a distance A from sensors 31 to markings 30, 100 mm to 200 mm are intended. A storage medium of safety apparatus 38 contains the corresponding relative distances of individualized markings 30. With the aid of markings 30 together with sensors 31, it is possible in all instances to detect a real position of carriage 28 on rail 29 via safety apparatus 28 and a sensor apparatus 40 formed by markings 30 and sensors 31 independently of the function of encoder device 37. A malfunction of encoder device 37 or slippage or a malfunction of sensors 31 and markings 30 can be directly detected by safety apparatus 38. Vis safety switch 39, a drive unit (not shown) can be shut down via safety switch 39.

[0047] FIGS. 3a and 3b each show a graph of a spatial transceiver 41 of an RFID transceiver (not shown) and RFID transponder 42, 43 disposed in relation thereto. RFID transponders 42, 43 are disposed on a rail (not shown in this case), the RFID transceivers being moved passed RFID transponders 42, 43 in a direction R by moving RFID transceivers. The RFID transceiver is positioned at the origin of the graph and RFID transponders 42 and 43 are positioned in an operational range AB at a distance in the direction of the Y-axis of the graph. When the RFID transceiver is moved in direction R, as shown in FIG. 3a, RFID transponder 42 exits transceiver area 41 at an exit point 44 and RFID transponder 43 enters transceiver area 41 at an entry point 45. FIG. 3b shows a movement in the opposite direction. Exit point 44 and entry point 45 can be detected by losing or establishing radio contact between the RFID transceiver and RFID transponder 42 and/or 43. This permits precisely determining a position of the RFID transceiver in relation to RFID transponders 42 and 43 and a movement direction in the X-axis.

[0048] A combined view of FIGS. 4 to 6 shows different options for a relative arrangement of markings 46 and sensors 47. Distance X indicated here can be 0.3 m or 0.45 m.

[0049] FIG. 7 shows a schematic view of markings 48 on a rail 49 and sensors 50 moved in relation thereto. Sensors 50 are connected to a safety apparatus 51 which is coupled with an encoder device 52. Safety apparatus 51 identifies exit points 53 and entry points 54 of each marking 48 at transceiver areas (not shown) of sensors 50. Via exit point 53 and entry point 54, a position point 55 of corresponding sensors 50 can be determined. Overall, a marking 48, and thus a position signal, can always be detected via exit points 53, entry points 54 and position points 55 despite a large distance of markings 48.

[0050] FIG. 8 shows a schematic view of a rotary encoder 56 having a base unit 57 for obtaining a rotary encoder signal, or rather a rotation angle signal and/or a rotational speed signal, of a rotary encoder 58 for processing these signals, of a safety apparatus 59, of a switching output 60 and of a field bus interface 61. Rotary encoder 56 is supplied with electric energy via a voltage source 62. Sensors 63 are each connected to safety apparatus 59 using a supply line 64 and a data line 6. In relation to sensors 63, markings 66 are disposed on a rail 67. Switching output 60 is connected to a relay 68 and field bus interface 61 is connected to a field bus 69. Safety apparatus 59, switching output 60 and field bus interface 61 are designed modularly, meaning they can each be combined with base unit 57 and rotary encoder 58 independently of each other. Hence, rotary encoder 56 can be adapted to many applications as required. Rotary encoder 56 along with safety apparatus 59 and a sensor apparatus 70, which is connected thereto and is formed from sensors 63 and markings 66, comprises a safety device 71.

[0051] FIG. 9 shows a process sequence for an operation of conveyor means, as shown in FIG. 1. In a first method step 72, a system setting is first carried out via a silent running of the carriage over rail 12. In this context, position signals of markings 19 are detected by sensors 22 or rather sensor apparatus 14. The distances of the position signals or rather the markings 19 are stored in safety apparatus 25. The distances are calculated from the rotational angle signal and/or the rotational speed signal of encoder device 17. In method step 73, an acceleration is continuously measured via encoder device 17 and slippage is detected by safety apparatus 25 during acceleration leaps. In method steps 74 and 75, both sensors 22 detect, independently of each other, markings 19 using an entry point, position point and exit point when traversing them, safety apparatus 25 comparing the obtained points to the points stored in method step 72 for each sensor 22 and detecting a deviation where appropriate. In method step 76, an assumed indirectly determined position of the carriage is corrected according to a real position if a deviation of the corresponding points could be detected in method steps 74 and 75.