RFID prevents excavator mistakes

Liebherr chose RFID from Pepperl+Fuchs to make sure that the wrong bucket and attachments aren't selected by excavator operators.

The Liebherr Likufix system is a quick-change solution for buckets and attachments fitted to hydraulic excavator arms.

It enables the driver to change the attachment without the need to exit the cab.

Up to 10 attachment configurations can be stored in the onboard control system and the driver can quickly select the one to be used from an LCD display.

The hydraulic settings and connections are then all taken care of automatically.

However, if the driver mistakenly selects the wrong attachment (either on the display or at the point of changeover) the wrong settings could be applied, potentially resulting in incorrect operation or damage to the equipment.

To guard against this occurrence the system must be able to automatically identify which tool is fitted so that it can apply the correct settings and for this identification process Liebherr chose RFID from Pepperl+Fuchs.

The challenge was to find an identification system that would be robust enough to cope with the environment.

Continuous exposure to dirt, oil and water meant that an optical solution such as barcoding would never be reliable enough.

A low-tech alternative would have been an array of proximity switches sensing a corresponding array of metal targets on the tool, but for the number of tools available this would have taken up too much room and it would also increase the complexity of the installation.

The read head chosen was the cylindrical M18 housing similar to that of an inductive proximity sensor, fully encapsulated and waterproof to IP67.

The tag chosen was again a resin-encapsulated type in a cylindrical threaded M16 housing.

The flush mounting design of the tag means that it can be mounted to the tool so that damage from the day to day use is almost impossible and the extra protection of IP69K means that pressure washing of the tools will not harm the tag.

In order to communicate to the onboard control system Pepperl+Fuchs designed a new control unit with a CAN bus interface.

Using a read/write chip in the tag, the system can be used to identify the tool selected and record the number of hours it has been in use.

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