Tablet App to control safety critical functions on farming machines

摘要

Since the introduction of the first iPhone in 2007 and the first iPad in 2010 the utilization of smart devices became common in large parts of private and professional life. A continuously growing number of apps in the agricultural sector support the farmer in different areas and activities of his business. Smartphones and tablets are found today in nearly each cabin of an agricultural machine. Farmers are using smart devices to communicate with each other, control logistics, check the weather or document their activities on the go. Because of the high number of smart device already utilized in agriculture, farmers raised the question, why they cannot use their existing tablets also to control working machines as a replacement for dedicated control terminals. Following this demand, CLAAS developed a concept, how to utilize a tablet app as user interface to control agricultural machines attached to a tractor. The developers needed to overcome several technical challenges as part of this concept: 1. A consumer tablet has not interface to the CAN Bus of the machine. Thus, a additional hardware as gateway between the CAN bus of the machine interface and the tablet needs to be developed. 2. To control machines regardless of their brand, the tablet app needs to follow the ISO 11783 (ISOBUS) standard. 3. Machine functions operated by the tablet app maybe harmful for the operator or people near to the machine. Thus, the tablet app needs to comply with functional safety guidelines of the AEF based on the ISO 25119 As a result of this effort an ISO 11783 compatible universal terminal (ISO UT) was realized as tablet app and an additional hardware component (CLAAS wireless interface) that connects the tablet to CAN bus of the machine.