Leuze: Sensor solutions for AGV

by donpedro

Typical application solutions for automatic high-lift trucks, platform vehicles and tractor vehicles
Automated guided vehicles (AGV) must transport material or goods from A to B quickly, safely and autonomously. Depending on the application and type of material to be transported, an automatic high-lift truck, a platform vehicle or a tractor vehicle may be best suited.
An AGV is controlled via optical guidance, grid navigation or so-called natural navigation. Our sensor solutions also guarantee the precise storage and retrieval of pallets, safe transport even with speed changes as well as vibration-free transfer of the transport material.
The portfolio ranges from cost-optimized sensors for detection to high-resolution navigation and safety solutions.

Automatic high-lift truck
The automatic high-lift truck is frequently used in high-bay warehouses, where it serves as a free-moving high-bay storage device.

Vertical positioning of the load receptacle
It is important that the load receptacle always be positioned at the correct height. Only in this way is it guaranteed that the pallet is safely stored and retrieved.
The AMS 300i sensor delivers measurement data every 2 ms with an absolute accuracy of ±2 mm. This measurement data can be transferred to the control via a wide range of interfaces.

Pallet and rack detection
From moving in to picking up the pallet with the load receptacle to placement of the pallet in the warehouse: the vehicle must always detect whether the path is free. The detection of the pallet itself as well as the edge of the shelf rack is also essential.
With the sensors of the 3 series, very precise switching points can be defined independent of material by means of which the pallet and shelf rack can be reliably detected. With up to two digital switching outputs, solutions to these different applications can be found with just one sensor.

Safeguarding the transportation path with natural navigation
An AGV always travels a predefined path in both directions. To orient itself in the surroundings during navigation without the use of reflectors and to safeguard the transportation path, the surroundings must be scanned with millimeter accuracy.
The RSL 400 safety laser scanner is an area scanner that scans its surroundings with a resolution of 0.1°. A very accurate map of the surroundings is thereby generated for the navigation. With up to 100 switchable protective fields, the safety area of the AGV can be adapted to the respective requirements at any time.

Position detection of transport material
For safe transport, it is essential to check whether the pallet or the transport material was correctly picked up by the vehicle.
With the HRT 25B sensor, up to two switching points can be taught in. The time-of-flight technology used here helps to set the switching points for the required distances nearly independently of material and color.

Integration of safety sensors
All safety functions used on the vehicle must be logically linked to one another. One example is the changeover of the protective fields of a safety laser scanner depending on the safely monitored travel speed.
With the configurable safety controls of the MSI 400 series, safety sensors and functions can be efficiently integrated. Though just 45 mm wide, there are 24 inputs/outputs available in the base module. These support the connection of incremental sensors for safe speed monitoring according to EN 61800-5-2 (available soon).

End positioning of load receptacle
The position of the load receptacle must always be ensured. It should, for example, be in a defined position when changing from slow to fast speed.
The IS 212 inductive switch with M12 external thread detects the position of the load receptacle. Large operating ranges – and a small size – save space and reduce costs here.

Pass-under and platform vehicles
In semi-automatic production areas such as semiconductor or display production, this type of AGV is used as a more flexible alternative to permanently installed conveyor systems.

Grid navigation
To find a predefined path, an AGV must always know exactly where it is, regardless of whether it is moving slowly or at high speed.
A simple and reliable solution is grid navigation. The DCR 200i code reader detects 2D-codes that are affixed to the floor in a defined grid even during fast movements. In doing so, the DCR 200i determines the code information and the angle of rotation.

Fine positioning
To ensure error-free transfer of the transport material, the vehicle must be positioned at the transfer station with millimeter accuracy.
The camera-based IPS 200i sensor determines its position relative to a marker – such as a through hole in the material – with millimeter accuracy. The sensor transfers its absolute measurement values to the control via the interface in millisecond intervals.

Presence control of transport material
There must be no errors when loading the transport material. It is therefore important to accurately determine its position after every loading and unloading operation.
The compact retro-reflective photoelectric sensors of the 5 series precisely determine the position of the transport material. In addition, technologies such as A²LS make the sensors insensitive to ambient light. And the highly visible light spot makes the products very easy to adjust.

Conveyor control
The loading and unloading operation should be activated as easily and efficiently as possible. Often, just one signal suffices here.
The command for activating or deactivating the conveyor is transferred easily, contact-free and economically between vehicle and conveyor system with a 3 series throughbeam photoelectric sensor. The photoelectric sensors can be aligned quickly thanks to their clearly visible indicator LEDs with all-round visibility. Insensitive to ambient light, they function reliably stable.

Tractor vehicle
Tractor vehicles are often used if material needs to be delivered on belts. For example, in the automotive industry or in the production of white goods.

Optical guidance
An AGV must move safely and efficiently through its surroundings. Often, however, expansive production and storage areas pose a challenge. Moreover, many sensors are unsuitable for integration in flat vehicles due to their dimensions.
One simple possibility is optical guidance. The vehicle follows a high-contrast track on the floor that helps the sensor in the vehicle determine its position. The OGS 600 compact sensor is available in models with different detection widths and interfaces. Its minimum distance from the floor is just 10 mm.

Safeguarding the transportation path
To safeguard the transportation path of an AGV, a defined area in front of the vehicle must be checked and the vehicle safely stopped in the event of danger.
The RSL 400 safety laser scanner reliably monitors an area of 8.25 m in a scanning angle of 270°. Due to the possibility of switching the protective fields, the protective field size can be dynamically adapted to the speed.


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