Upgrade of AGV equipment at Claas
Technical requirements and implementation
Based in Harsewinkel, Germany, Claas is a leading manufacturer of agricultural machinery (combine harvesters, tractors, harvesting machines). In 2012, its existing AGV equipment (cabs and cab carriers), which had been installed in 2011, was upgraded by BeeWaTec-Systems GmbH of Pfullingen, Germany, benefitting from both a new central control system and new vehicle controllers. 37 optically guided vehicles (AGVs) operate on 2 tracks. On track 1, the driver’s cab is manufactured on a continuous assembly line. On track 2, the cab is combined with the base carrier.
The battery charging and changing tower provides a shared interface for the two systems. This is where the batteries of both types of vehicle are changed during live operation. The process is fully automated.
The old vehicle controllers for the 7 cab carrier AGVs and the 30 cab AGVs have been replaced by a new PLC along with an intelligent I/O card (the latter being an in-house innovation). The entire safety technology of the AGVs was brought up to the very latest standard with FlexiSoft by SICK AG. The PLC is a standard component which is also used for snow groomers.
The existing master control was replaced by a Siemens software PLC (WinAC). WinCC provides a flexible reporting system and visualisation solution. The software PLC is characterised by the fact that it combines conventional PLC functionality with PC hardware (Windows). Accordingly, secure control and visualisation/operation is safeguarded by hardware (a device).
Additionally, changes were made to expand the track for the cab AGVs at the same time, as a picking zone had to be integrated into the process.
The highlights of the new master control include central timing of the vehicles and optimised traffic control. Furthermore, the master control has been integrated into the Claas quality control loop and meets all requirements relating to production control (Q alarm, Q stop). The production process is completed by additional functions such as go to sleep/wake up, break control, freely configurable cycle times and assembly times as well as activation/deactivation of functions.
The AGV master control receives the new production schedules on a daily basis via the company network and also monitors incoming goods to ensure that the correct types of cab frame are made available for assembly. The master computer also triggers the signal which tells the forklift driver which cab is required next in the production process.
Implementation in practice
The upgrade to the new master control took place during the plant’s annual shutdown period. Over a 5-week period and with production still running, the 37 vehicles were gradually upgraded and integrated into the system. So that all required functions could be supported, communication between the vehicles and the master computer had to be completely redefined. The biggest challenge was to operate both protocols in parallel so that old and new vehicles could be in operation at the same time. This was the only way to achieve a smooth transition without interrupting the production process.