Abstract
An automated guided vehicle configured for driverless, autonomously acting operation for a load to be transported includes a control system configured to control and to steer the automated guided vehicle, an evaluation unit configured to generate a signal for stopping the automated guided vehicle, and a detector device configured to detect an arrangement of the load and/or of a lifting platform. The detector device is connected to the control system. The automated guided vehicle is stopped automatically when the detected arrangement of the load deviates from a predefined arrangement of the load and/or as a result of an expected lowering of the lifting platform.
Claims
1. An automated guided vehicle for driverless, autonomously acting operation for a load to be transported, comprising: a control system configured to control and to steer the automated guided vehicle; an evaluation unit configured to generate a signal for stopping the automated guided vehicle; and a detector device operably connected to the control system and configured to detect an arrangement of the load and/or of a lifting platform, wherein the automated guided vehicle is stopped automatically when the detected arrangement of the load deviates from a predefined arrangement of the load and/or as a result of an expected lowering of the lifting platform.
2. The automated guided vehicle according to claim 1, wherein the control system comprises a first control unit configured to control a desired direction of travel and a speed of the automated guided vehicle, a second control unit configured to control a motion of the automated guided vehicle, and a third control unit configured to control safety of the automated guided vehicle.
3. The automated guided vehicle according to claim 1, wherein the control system comprises at least one memory protected against power failure and configured to store the detected arrangement of the load and/or of the lifting platform.
4. The automated guided vehicle according to claim 3, wherein the memory is a flip flop.
5. The automated guided vehicle according to claim 4, wherein the flip flop is configured to store the detected arrangement of the load and/or of the lifting platform during a loading process of the automated guided vehicle.
6. The automated guided vehicle according to claim 4, wherein the flip flop is configured, when re-activation occurs after a power failure, to directly store again the detected arrangement of the load and/or of the lifting platform and to continue a transportation process automatically.
7. The automated guided vehicle according to claim 2, wherein the detector device comprises a lower lifting platform sensor and an upper lifting platform sensor.
8. The automated guided vehicle according to claim 7, wherein the lower lifting platform sensor and the upper lifting platform sensor are connected to the third control unit.
9. The automated guided vehicle according to claim 1, wherein: the detector device includes a load sensor configured to detect the arrangement of the load, and the load sensor includes an inductive proximity sensor.
10. The automated guided vehicle according to claim 1, wherein the evaluation unit is integrated into the control system.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The disclosure and the technical environment are explained in more detail below with reference to figures. In this instance, identical components are characterized by identical reference symbols. The illustrations are provided schematically and not for illustrating size relationships. The explanations which are given with respect to individual details of a figure can be extracted and freely combined with contents from other figures or the description above, unless something else necessarily arises for a person skilled in the art or such a combination is explicitly prohibited. In the drawings:
[0037] FIG. 1 shows a plan view of a driverless, autonomously acting automated guidied vehicle with a control system and a detector device;
[0038] FIG. 2 shows a block diagram with the control system to which the detector device and a memory which is protected against power failure are connected;
[0039] FIG. 3 shows a side view of the automated guided vehicle according to FIG. 1 with loaded load and a sensor system;
[0040] FIG. 4 shows a circuit diagram for a first logic circuit; and
[0041] FIG. 5 shows a circuit diagram for a second logic circuit.
DETAILED DESCRIPTION
[0042] FIG. 1 shows a plan view of a driverless, autonomously acting automated guided vehicle 1 with a control system 3 and a detector device 5 (see FIG. 2).
[0043] The automated guided vehicle 1 which is presented here and is loaded with a load 2 (see FIG. 3) comprises at least the control system 3, which controls and steers the automated guided vehicle 1, and an evaluation unit 4 (see FIG. 2) which generates a signal for stopping the automated guided vehicle 1. The detector device 5 (see FIG. 2) comprises a load sensor 6 for detecting the arrangement of the load 2 and a lower lifting platform sensor 40 and an upper lifting platform sensor 41 for detecting undesired lowering of the lifting platform 16 of a lifting and lowering device 14 (see FIG. 3). The control system 3 comprises a first control unit 9 for the desired direction of travel and the speed, a second control unit 10 for the motion, and a third control unit 11 for the safety of the automated guided vehicle 1. In the specific application, two first motors 12 are present for the travel motion of the automated guided vehicle 1, both are equipped with a secure rotational speed encoder 15 (“SIL2” denotes a safety level and can also be SIL1 or 3 depending on the requirement). A further motor 13 serves to move the lifting and lowering device 14 (the lifting platform) and is monitored by inductive sensing of the loading area position (without a rotary encoder). A laser scanner 8 which monitors an unloading area 38 and the load 2 is arranged at the rear end of the automated guided vehicle 1.
[0044] FIG. 2 illustrates a block circuit diagram with the control system 3 to which the detector device 5 is connected. The lower lifting platform sensor 40, the upper lifting platform sensor 41 and the load sensor 6 are connected to the electronic control system 3 by a data-conducting connection 17. The second control unit 10 is connected via rotary encoder 15 (setpoint rotational speed) to two first motors 12 for the vehicle motion. A brake system 18 is connected to the control system 3 which can generate a signal to the first motors 12 for stopping the automated guided vehicle 1. The brake system 18 can also act alone, or in combination with the first motors 12, on the automated guided vehicle 1. Furthermore, a second motor 13 for driving the lifting and lowering device 14 is connected to the control system 3. 19 denotes a flip flop 27 (see FIGS. 4 and 5) as a memory which is protected against power failure and is connected to the controller 3. A battery 18 is connected to the flip flop 27, in order to retain the program in the memory 19 during a power failure.
[0045] FIG. 3 shows a side view of the automated guided vehicle 1 according to FIG. 1 with a loaded load 2. An inductive proximity sensor, e.g. a sensor with an inherent safety function, is present as the load sensor 6. The load sensor 6 is arranged on the rear side of the loading area 1.1 of the automated guided vehicle 1 and is oriented in the direction of the load 2. The load 2 is composed here of loading material 21 and a dolly 22, with which the loading material 21 can be transported. Wheels of the automated guided vehicle 1 are denoted by 20.1, 20.2 and 20.3. Wheels of the dolly 22 are denoted by 23.1 and 23.2. The lifting and lowering device 14 is installed in the form of a scissor-type lifting unit, at the upper end of which there is a lifting platform 16, on the loading area 1.1 of the automated guided vehicle 1. The lifting platform 16 supports the dolly 22 with the loading material 21. The directions of movement of the lifting and lowering device 14, of the lifting platform 16, of the dolly 22 and of the loading material 21 in the vertical direction are denoted by C and D. Furthermore, the lower lifting platform sensor 40 and the upper lifting platform sensor 41 are mounted one on top of the other on the rear side of the loading area 1.1 and are oriented in the direction of the lifting platform 16. A (conductive) iron element 39, e.g. a screw, is attached to the lifting platform 16 and interacts with the inductive lifting platform sensors 40 and 41 and with the load sensor 6 and can be sensed by them by means of measuring technology.
[0046] FIG. 4 shows a circuit diagram for a first embodiment of a logic circuit 25. The load sensor 6, the upper lifting platform sensor 41 and the lower lifting platform sensor 40 are connected to a first input 28, a second input 29 and respectively a third input 30. The inputs 28 and 29 lead to a first AND gate 34, downstream of which a flip flop 27 and a second AND gate 35 are arranged. The third input 30 is connected to the flip flop 27. A first output 32 and the second AND gate 35 are arranged downstream of the flip flop 27. A second output 33 is arranged downstream of the second AND gate 35. The basic sequencing logic for this can be summarized, for example, as follows: [0047] 1. The first control unit 9 transmits the desired direction of travel and the speed to the second control unit 10. [0048] 2. The second control unit 10 passes on the desired direction of travel to the third control unit 11, calculates the setpoint rotational speeds and transmits them to the motors. [0049] 3. The third control unit 11 detects by means of the load sensor 6 (logic 1) and the upper lifting platform sensor 41 (logic 1) that a load 2 has been loaded on, and it stores this state in a secure flip flop 27. [0050] 4. If the load 2 slips during the transportation travel (load sensor=logic 0), the third control unit 11 sets the speed to v=0 mm/s by means of the second control unit 10. (The setpoint speeds of the third control unit 11 have priority over the desired speeds of the first control unit 9.) [0051] 5. The third control unit 11 detects the unloading of the load 2 by means of the lower lifting platform sensor 40 (logic 1) and resets the flip flop 27.
[0052] FIG. 5 illustrates a circuit diagram of a second embodiment of a logic circuit 26. The logic circuit 26 corresponds largely to the logic circuit 25 according to FIG. 4, but with the difference that a resetting element 37 is connected to a fourth input 31, downstream of which a third AND gate 36 is arranged. The basic sequencing logic for this can be summarized, for example, as follows: [0053] 1 The first control unit 9 transmits the desired direction of travel and the speed to the second control unit 10. [0054] 2. The second control unit 10 passes on the desired direction of travel to the third control unit 11, calculates the setpoint rotational speed and transmits it to the motors. [0055] 3. The third control unit 11 detects by means of the load sensor 6 (logic 1) and the upper lifting platform sensor 41 (logic 1) that a load 2 has been loaded on and stores this state in a secure flip flop 27. [0056] 4. If the lifting platform 16 unexpectedly lowers during the transportation travel (logic 0), the third control unit 11 sets the speed to v=0 mm/s via the second control unit 10. (The setpoint speeds of the third control unit 11 have priority over the desired speeds of the first control unit 9.) [0057] 5. Controlled lowering is released after a safely monitored reverse travel e.g. by means of a laser scanner 8, into an unloading area 38 (see FIG. 1) (unload=logic 1).
[0058] The driverless, autonomously acting automated guided vehicle 1 (AGV) presented here is preferably used, for example, in factories, warehouses, supermarkets or hospitals. Colllisions (in particular with a person and/or an object) and/or disorientation are avoided by means of sensors, for example laser scanners, inductive proximity sensors, ultrasonic sensors and/or 3D cameras. For example pallets, crates, shelves, individual parts or small load carriers (SLCs) with or without dollies are transported.
LIST OF REFERENCE SYMBOLS
[0059] 1 Automated guided vehicle [0060] 1.1 Loading area [0061] 2 Load [0062] 3 Control system [0063] 4 Evaluation unit [0064] 5 Detector device [0065] 6 Load sensor [0066] 7 Sensor System [0067] 8 Laser scanner [0068] 9 First control unit [0069] 10 Second control unit [0070] 11 Third control unit [0071] 12 First motor [0072] 13 Second motor [0073] 14 Lifting and lowering device [0074] 15 Rotary encoder [0075] 16 Lifting platform [0076] 17 Data-conducting connection [0077] 18 Brake system [0078] 19 Memory [0079] 20.1,20.2,20.3 Wheels of automated guided vehicle [0080] 21 Loading material [0081] 22 Dolly [0082] 23.1,23.2 Wheels of dolly [0083] 24 Battery [0084] 25 First logic circuit [0085] 26 Second logic circuit [0086] 27 Flip flop [0087] 28 First input [0088] 29 Second input [0089] 30 Third input [0090] 31 Fourth input [0091] 32 First output [0092] 33 Second output [0093] 34 First AND gate [0094] 35 Second AND gate [0095] 36 Third AND gate [0096] 37 Resetting element [0097] 38 Unloading area [0098] 39 Iron element [0099] 40 Lower lifting platform sensor [0100] 41 Upper lifting platform sensor [0101] A,B,C,D Directions of movement
