Method and device for determining the position of vehicles in a driverless transport system.

The invention relates to a method for locating vehicles driverless transport systems according to the preamble of claim 1.

Driverless transport systems are used for example in production halls or warehouses. They require constant positioning of the vehicle or of the vehicles in order to meet the prescribed path safely.

Conventional processes use for locating the sunken guide cables or other expensive fixed equipment for the continuous detection, and recently reinforced the use of image-processing methods. The disadvantage of this method is the high cost and low flexibility against web changes, including the search wire.

Moreover - although from the road - a distance measurement is known in which for determining the distance of a preceding vehicle passive or active measurement methods are applied. This is based on the transmission and propagation time measurement of ultrasonic signals. In an active method of measurement with an infrared / ultrasonic transponders is emitted from a first vehicle from an infrared signal as a start signal that causes the transmission of an ultrasonic signal at a second vehicle. From the elapsed time between the transmission of the infrared signal and the receipt of the ultrasonic signal, the distance of the first vehicle from the second can then be determined. Of course, the term of the infrared signal is set to zero.

However, this method requires a relatively narrowly defined alignment of the vehicles ahead of each other and only allows the measurement of the distance between the vehicles, but not their spatial position.

The invention has for its object to provide a method for locating vehicles AGVs, which is easy to install even in existing transport systems and allows flexible web guide and change the trajectory of the vehicles.

This object is achieved in a method according to the preamble of claim 1 by the features specified in the characterizing features.

A basic idea of ​​the invention is based on a wireless Abstandsmesssung between the or each vehicle (s) whose absolute position is to be determined, and fixed to provide only selectively arranged facilities. Is because this measurement is known, the distance to two spatially separated fixed installations that may be uniquely determined under the constraint of a rectilinear path of the vehicle or vehicles, the absolute position. If any path paths but at least three stationary devices are required.

In the wireless distance measurement, it is assumed that the shortest distance between two objects is measured, so reflections excluded or are not considered.

For wireless distance measurement, ultrasonic signals, which have a budget for the processing speed of signals propagation velocity are. The ultrasonic signals transmitted at a predetermined time, the elapsed time between the transmission and the reception can be readily determined.

The transmission time can be determined that electromagnetic start signals are transmitted, either induce or announce the transmission of ultrasonic signals. The fact is utilized that such signals compared to ultrasonic signals have negligible short duration, which practically does not affect the Meßgenaulgkeit due to the delay of the ultrasonic signals.

Corresponding means for transmitting ultrasonic signals and electromagnetic signals can be installed without major construction effort. A change of orbits be traversed is at once installed equipment possible only by changing the programming and requires no structural changes, making the process can be adapted to changed operating conditions very flexible.

The invention further relates to a locating device for driverless vehicles transport systems according to the preamble of claim 1.

In this regard, it is an object to provide a locating device for vehicles AGVs, which is easy to install even in existing transport systems and allows flexible web guide and change the trajectory of the vehicles.

This object is achieved with a location device according to the preamble of claim 11 by the features specified in the characterizing features.

Further developments and advantageous embodiments of the invention will be apparent from the claims, the description and the drawings, on the basis of the invention is illustrated.

In the drawings: <dl id="dl0001"><dt>Fig. 1</dt><dd>a sketch of a comprehensive multiple vehicles driverless transport system with a locating device in a manufacturing or warehouse,</dd><dt>FIG. 2</dt><dd>a block diagram of the locating device shown in FIG. 1.</dd></dl>

In Fig. 1, a locating device for a plurality of vehicles is shown complete driverless transport system. The transport system is used here for example to in a warehouse 60 goods stored by stations 34, 36, 38. 40, 42, 44; 46, 48, 50 to transport by vehicles 10, 12, 14 to a station 52nd

The vehicles are equipped with control devices that make it possible to move them along railway curves 54, 56, and 58 at the stations 34, 36, 38; 40, 42, 44; 46, 48 to be holding 50. The control devices thereby comprise computer memory and affecting the vehicle drive and steering accordingly gespelcherter data of trajectories and stations.

To long-term to ensure a high accuracy in maintaining the trajectories and target safe start of the stations, the knowledge of the current position is necessary. For this purpose, the driverless transport system via a locating device that includes means to to be located vehicles 10, 12, 14 and three stationary devices 16, 18, 20.

Between the devices on the vehicles to be located 10, 12, 14 and the fixed-position devices 16, 18, 20 ultrasonic signal transmission paths are formed. By measuring the transit times of the transmitted at predetermined times ultrasonic signals can be the distances between the vehicles 10, 12, 14 and the fixed-position devices 16, 18, determine 20 and from 12, 14 calculate the spatial coordinates of the current location of each vehicle 10, ,

The stationary devices 16, 18, 20 are mounted on two corners and the center of one side of the hall 60. This can be determined accurately determine their coordinates at all possible locations. Thus, the shortest distance covered by the sound can be detected, it is also expedient to install the transmitter and receiver in a sufficient height. This is largely sight on the transmission path and ensures disturbing reflections are virtually eliminated.

If the vehicle is to only describe a very limited trajectory, two fixed equipment may be sufficient. Conversely, for very large, labyrinthine halls or grounds the need to provide more than three stationary facilities.

For triggering the ultrasonic signals and thus the beginning of the measurement, several alternatives present. One option that is also used in the illustrative embodiment, the application is to transmit electromagnetic signals start of the reception locations of the ultrasonic signals from the beginning of the time of flight measurement. These are received at the transmitting locations of the ultrasonic signals and control the emission of the ultrasonic signals.

Another, but not shown here alternative provides to transmit electromagnetic start signals from the transmitting locations of the ultrasonic signals from the beginning of the time of flight measurement. This notice to the receiving locations of the ultrasonic signals to the emission of ultrasonic signals.

The first alternative has the advantage that the fixed-position devices can be completely self-sufficient except a power supply and do without intelligent control or internal communications. Control of the emission of ultrasonic signals for the beginning of the time of flight measurement may instead be shifted to the vehicle, where in any case an intelligent control system for the drive and the steering is already present.

Another embodiment of the invention, in turn, allows multiple possible solutions. So, an option that uncoded ultrasonic signals are transmitted in each case only from a transmitter at the time and the stations are launched or announced successively by differently coded electromagnetic signals start.

Although this solution is time-consuming because in a measurement cycle, the emissions of all ultrasonic transmitter and the decay of the sound must be awaited, but it has very low demands on the ultrasonic receiver and the evaluation circuits.

In another variants encoded ultrasonic signals, preferably of different, specific for each transmitter frequency can be started simultaneously and the ultrasonic signals selectively evaluated.

It succeeds in this way, be able to determine the distances between the vehicles and the fixed-position devices simultaneously and update faster.

Specifically, there is the structure of the locating device of the block diagram shown in Fig. 2. There, the fixed-position devices 16, 18 and 20 as well as the bodies of the vehicles are given 10 and 12. FIG.

The stationary devices 16, 18 and 20 are constructed in the exemplary embodiment are identical and consist of a transmitter 24 for ultrasonic signals and an RF receiver 32 for electromagnetic start signals. Where the recipient 32 a start signal, it causes immediately the transmitter 24 to emit an ultrasonic signal.

The vehicles 10 and 12 have both a control and evaluation device 22. In addition to controlling the drive and the steering of the vehicles 10 and 12, the control and evaluation device 22 determines the running times of 26 and 28 received from ultrasonic receivers signals and calculates over the distances from the fixed-position devices the current positions of the vehicles 10 and 12. FIG.

A arranged in the vehicle 10 RF transmitter 30 is also controlled by the control and evaluation device 22 and that serves these stations 30 to 18, 20 to transmit electromagnetic signals start at the fixed-position devices 16,.

In the illustrated embodiment with multiple vehicles 10, 12 electromagnetic start signals are only of a lead vehicle, here the vehicle 10, and sent these start signals are received and evaluated by the fixed-position devices 16, 18, 20 and the other vehicles 12th Instead of a private radio station has the vehicle 12 therefore includes an RF receiver 32nd

The advantage of this configuration is that the beginning of the transmission of ultrasonic signals is controlled only by the control and evaluation device 22 of this vehicle and therefore temporal Voters or synchronizations of the vehicles may be mutually eliminated.

are in each vehicle 10, 12 located on the transverse sides to the vehicle axle, that the front and the back, the ultrasonic receivers 26, 28. This receiver 26, 28 are therefore housed spatially separate and deliver the reception of ultrasonic signals of different field strengths and / or maturities. From this information it is possible, in addition to the current position and the respective orientation of the vehicle 10 to determine 12th