METHOD AND SYSTEM FOR DETERMINING THE POSITION OF AT LEAST ONE INSTALLATION CONVEYOR MACHINE

Description

[0001] The present invention relates to a method and a system for determining the position of at least one industrial truck in an area with a plurality of stationary radio stations.

[0002] Several different approaches exist for determining the position of industrial trucks in warehouses and other defined environments. For example, RFID transponders can be embedded in the floor. When an industrial truck passes over them, its position can be communicated. In the field of radio technology, time-of-flight measurements and / or angle-of-incidence measurements are known methods for determining the position of the industrial truck relative to statically mounted units.

[0003] From DE 10 2009 004 854 B4 a method and system for determining the position of a forklift truck is known, in which a multi-axis gyroscope sensor, in particular a gyroscope, is used.

[0004] From DE 10 2001 018 520 A1 a method for approaching a storage location with a forklift truck is known, in which the current position of the forklift truck is recorded and a lifting height preselection value adapted to the height of the storage location to be approached is set for the current position.

[0005] From DE 10 2009 013 671 A1, a device for determining the position of a forklift truck is known. In this device, several light sources are positioned at predefined locations, and radiation uniquely identifying each light source is emitted from them. A forklift truck evaluates the incoming radiation, taking into account the relative angles to each other, in order to determine its current position and orientation between the three light sources.

[0006] German patent DE 10 2008 011 539 B3 discloses a fully automated, driverless straddle carrier equipped with sensor systems for vehicle tracking and navigation. The signals from the sensor systems are evaluated and monitored in a sensor fusion system, and the resulting current coordinates of the vehicle are then transmitted to a system of electrical controls for automatic steering, driving, and positioning.

[0007] From EP 2 154 478 A1, a method for driver assistance in a forklift truck is known, which includes a tracking device for determining the position of the forklift truck. In addition, the warehouse management system transmits information about the position of other forklift trucks to the control computer, and if another forklift truck is on the approach path, an alternative approach path is calculated.

[0008] The invention is based on the objective of providing a method and a system for determining the position of at least one industrial truck in an area with a large number of stationary radio stations, which can determine the current position of the industrial truck with the greatest possible accuracy.

[0009] According to the invention, the problem is solved by a method having the features of claim 1 and by a system according to claim 9. Advantageous embodiments are the subject of the dependent claims.

[0010] The method according to the invention is designed and intended to determine the position of at least one industrial truck in an area with a plurality of stationary radio stations. The term "position" here encompasses the spatial position of the industrial truck and its orientation within that position. The position of the at least one industrial truck is determined in an area with a plurality of stationary radio stations, which transmit a position signal in response to a position determination signal. The industrial truck is equipped with a mobile radio station. Stationary and mobile radio stations are designed as transmitting and receiving units capable of receiving and transmitting radio signals. In the method according to the invention, vehicle data relating to the vehicle's speed and / or steering angle are determined. The determined vehicle data describe the actual or target state of the vehicle.The method according to the invention further provides that a position determination signal is sent from the mobile radio station to the stationary radio stations. The stationary radio stations transmit a signal in response to a received signal.

[0011] Each position determination signal emits its own position signal. According to the invention, additional data is appended to the position determination signal and / or the position signal. In the case of the position determination signal, i.e., the signal emitted by the industrial truck, vehicle data relating to the truck's speed and / or steering angle is appended as additional data. In the case of the position signal, i.e., the signal emitted by the stationary radio stations, the additional data includes position data of industrial trucks. The method provides for receiving multiple position signals with the mobile radio station, wherein the position signals originate from at least three different stationary radio stations. By using three stationary radio stations, the position of the industrial truck is uniquely determined.

[0012] In a preferred embodiment, the current position is determined using a Kalman filter incorporating the acquired vehicle data. The Kalman filter can utilize an extended state space for the industrial truck, which, for example, also includes its translational or rotational movement, thus enabling a more precise position determination.

[0013] Preferably, the vehicle data also includes the current position of the industrial truck. In this way, the current vehicle positions are also provided to the stationary radio stations along with the position signals, allowing the stationary radio stations to distribute the positions of the industrial trucks to all mobile radio stations using their position signals in the attached additional data.

[0014] In a preferred further development of the procedure, the mobile radio station receives information about the current position of other industrial trucks.

[0015] This information is derived from the received position signals. In this further development of the inventive method for position determination, position data from participating industrial trucks are also exchanged on the radio channel used for position determination. In one possible embodiment, this information is exchanged between the mobile radio stations, i.e., between the respective vehicles.

[0016] It is also possible to transmit information about the current positions of the industrial trucks from the stationary radio stations to all the trucks. The stationary radio stations determine the data on the current positions of the industrial trucks from the received position signals, which also include the current vehicle position.

[0017] In a preferred embodiment of the method, the at least one industrial truck reduces its own speed and / or changes its steering angle when the evaluation of the positions and / or movements of other vehicles indicates a risk of collision. In this embodiment of the method according to the invention, the industrial truck independently recognizes from the available data that there is an increased risk of collision in its position or surroundings. Therefore, the speed is reduced and / or the direction of travel is changed. At a reduced speed, it is easier for the operator of the industrial truck to react to impending collisions and avoid them. In the event of an impending collision, changing the direction of travel can also help to gain time for an evasive maneuver.

[0018] In a further preferred embodiment, several of the mobile radio stations respond to a position-determining signal with a vehicle position signal, so that a forklift truck receiving the vehicle position signal can determine its distance. This distance determination method using transmitted position signals can also be used to supplement the exchange of information on the current position of other forklift trucks.

[0019] The problem according to the invention is also solved by a system for determining position according to claim 9. The system according to the invention serves to determine the position of at least one industrial truck in an area with a plurality of stationary radio stations, which are configured to transmit a position signal in response to a position determination signal. Each industrial truck has a mobile radio station configured to transmit a position determination signal and to receive position signals. Furthermore, an evaluation unit is provided, which is configured to append additional vehicle data to a position determination signal to be transmitted and to extract position data for the industrial trucks from received position signals. The evaluation unit is also configured to determine a current vehicle position from at least three position signals.The system according to the invention has an evaluation unit which, on the one hand, determines the current vehicle position from received position signals and, on the other hand, is designed to send vehicle data with position determination signals and / or to separate position data from received position signals.

[0020] In a preferred embodiment of the system, the vehicle data includes the vehicle speed and / or steering angle of the industrial truck. More preferably, the vehicle data also includes the current vehicle position. The system according to the invention makes it possible to distribute position data for individual industrial trucks particularly effectively among all vehicles. On the one hand, the vehicles report their current vehicle position along with the vehicle data to the stationary radio stations, while at the same time the stationary radio stations distribute the position data of the industrial trucks along with the position signals to the industrial trucks. In this way, the position data of the other industrial trucks is made available to each industrial truck, so that collision avoidance can be carried out in a manner known per se.

[0021] In a further preferred embodiment of the system according to the invention, the evaluation unit is designed to determine position data from other industrial trucks from the received position signals. In this way, position data for the other industrial trucks is available locally at the individual industrial trucks.

[0022] In another preferred embodiment, the mobile radio stations are designed to receive signals from other mobile radio stations regarding the respective position of another industrial truck.

[0023] In this preferred configuration, the distribution of position data from other industrial trucks across the multitude of industrial trucks takes place not only via the stationary radio stations, but also directly between the mobile radio stations.

[0024] In a further preferred embodiment, the stationary radio stations are designed to determine the current positions of industrial trucks from the received position signals. The current positions of the industrial trucks determined in this way are then transmitted to the other industrial trucks along with their position signals.

[0025] The claimed scope of protection is determined by the attached claims.

[0026] Preferred embodiments of the invention are explained in more detail below. They show: Fig. 1 shows a schematic view of two industrial trucks with different connections for their mobile radio units, as well as three schematically represented stationary radio units in different designs, and Fig. 2 shows a warehouse with three stationary radio units.

[0027] Fig. 1Figure 1 shows a schematic view of a forklift truck 10, which has a mobile radio unit 12. The mobile radio unit 12 has a schematically depicted antenna 14. The radio unit 12 and antenna 14 together form a mobile radio station. The schematically depicted forklift truck 10 has a vehicle control unit 16, which is connected to the mobile radio unit 12 via internal wiring.

[0028] The industrial truck 20, also shown schematically, has a mobile radio unit 22 with an antenna 24. The vehicle control unit 26 is connected to the mobile radio unit 22 via a CAN bus 28.

[0029] The stationary radio stations are also referred to as anchors. Anchors 30, 32, and 34 are permanently installed within a storage area. Each anchor has an antenna for transmitting and receiving radio signals. Stationary radio station 30 is connected to the warehouse's data processing system via a local area network (LAN) and can thus access data from a warehouse management system, for example.

[0030] The stationary radio station 32 communicates with an actuator 36. A corresponding control command from the vehicle can be sent via the stationary radio station 32 to actuate the actuator 36. For example, an approaching forklift truck can trigger the opening of a warehouse door.

[0031] The stationary radio station 34 is connected to a sensor, making it possible to forward sensor values ​​recorded in the warehouse, such as brightness and temperature, to the forklift truck(s) in the warehouse.

[0032] Fig. 2 Figure 1 shows a schematic diagram of the radio tracking system for the two industrial trucks, 10 and 20. Industrial truck 20 has sequentially transmitted position signals to stationary radio stations 30, 32, and 34 via its mobile radio unit. Stationary radio stations 30, 32, and 34 respond with a position signal after a predetermined time interval. The distance to the stationary radio station can be determined from the time interval required for the response, which is calculated as twice the signal propagation time and a predetermined processing time for the stationary radio station. The position of industrial truck 20 can be determined from the distance to at least three stationary radio stations. The positions of these three stationary radio stations are known to industrial truck 20.

[0033] Furthermore, the vehicle's speed and steering angle are transmitted to the mobile radio station. This transmission occurs either via the vehicle's own CAN bus 28 or via dedicated lines 18. From the mobile radio station, this data, along with the vehicle's current position, is sent to the stationary radio stations, which then forward it to all other mobile radio stations.

[0034] Thus, the current position data and possibly also the current vehicle data regarding driving speed and steering angle are made available to all industrial trucks, enabling them to perform effective collision control.

[0035] In this industrial truck, the Kalman filter is used to supplement radio-based position determination with current data on vehicle speed and steering angle, processing this information to generate precise position data. This allows not only the determination of the individual vehicle's position, but also the determination of the positions of other vehicles. Furthermore, other industrial trucks can also utilize a Kalman filter if their speed and / or steering angle data are available.

[0036] The precise positioning system also has the advantage of generating position-dependent signals for the behavior of the forklift. For example, the travel speed can be reduced in areas where many other forklifts are located and moving. The forklift's position can also be exchanged between forklifts, either amongst themselves or via stationary radio units, allowing movements to be detected and the travel speed to be reduced when vehicle density is too high.

[0037] It is also possible to determine the distance to other vehicles by measuring the time of flight, as with stationary radio units. Reference symbol list

[0038] 10 Forklift 12 Mobile radio unit 14 Antenna 16 Vehicle control 18 Wired connection 20 Forklift 22 Radio unit 24 Antenna 26 Vehicle control 28 CAN bus 30 Stationary radio unit 32 Stationary radio unit 34 Stationary radio unit 35 LAN 36 Actuator

Claims

1. A method for determining the position of at least one industrial truck (20) in a region having a plurality of stationary radio stations (30, 32, 34) which emit a position signal in response to a position determination signal, wherein the industrial truck (20) comprises a mobile radio station (12), said method comprising the following method steps: - ascertaining vehicle data relating to the travel speed and / or a steering angle at the industrial truck (20), wherein the vehicle data also comprise the current vehicle position, - sending a position determination signal by means of the mobile radio station (12) to the stationary radio stations (30, 32, 34), - sending a position signal by means of each of the stationary radio stations (30, 32, 34) in response to a received position determination signal, - receiving multiple position signals from at least three stationary radio stations (30, 32, 34) by means of the mobile radio station (12), and - appending data in the form of the ascertained vehicle data to the position determination signal and / or appending data in the form of position data relating to other industrial trucks to the position signal, - ascertaining a current vehicle position from at least three received position signals, - wherein the stationary radio stations (30, 32, 34) ascertain current positions of industrial trucks from the received position determination signals and distribute said positions with their position signals to all mobile radio stations, - wherein the mobile radio station (12) ascertains information relating to the current position of other industrial trucks from the received position signals.

2. The method according to claim 1, characterized in that the current position is determined using a Kalman filter taking into account the vehicle data.

3. The method according to any one of claims 1 to 2, characterized in that information relating to the current position of other industrial trucks is directly received from the mobile radio stations (12) thereof.

4. The method according to any one of claims 1 to 3, characterized in that at least one industrial truck (20) reduces a speed and / or changes its steering angle if the evaluation of the position and / or movement of other industrial trucks indicates a risk of collision.

5. The method according to any one of claims 1 to 4, characterized in that multiple of the mobile radio stations respond to a position determination signal with a vehicle position signal, such that an industrial truck (20) sending the position determination signal can determine its distance from each of the industrial trucks sending the vehicle position signal.

6. The method according to any one of claims 1 to 5, characterized in that vehicle functions or external actuators (36) are switched depending on the position.

7. A system for determining the position of at least one industrial truck (20) in a region having a plurality of stationary radio stations (30, 32, 34) which are designed to emit a position signal in response to a position determination signal, wherein each industrial truck (20) comprises a mobile radio station (12) which is designed to send a position determination signal and to receive position signals, and comprises an evaluation unit which is designed to append additional data in the form of vehicle data to a position determination signal to be sent and / or to extract position data of other industrial trucks from received position signals, wherein the evaluation unit ascertains a current vehicle position from at least three position signals and the vehicle data include a travel speed and / or steering angle as well as a current vehicle position of the industrial truck, wherein the stationary radio stations (30, 32, 34) ascertain current positions of industrial trucks from the received position determination signals and distribute said positions with their position signals to all mobile radio stations and the mobile radio station (12) ascertains information relating to the current position of other industrial trucks from the received position signals.

8. The system according to claim 7, characterized in that the evaluation unit is designed to ascertain position data of other industrial trucks from the received position signals.

9. The system according to claim 7 or 8, characterized in that the mobile radio stations (12) are designed to receive signals relating to the respective position of another industrial truck from the other mobile radio stations.

10. The system according to any one of claims 7 to 9, characterized in that the stationary radio stations (30, 32, 34) are designed to ascertain current positions of industrial trucks from the obtained position determination signals.