The ISO 21815-2 technical specification, under development by the international ISO standardization body, defines the SAE-J1939-based communication interface for collision detection and avoidance systems. The growing adoption of hazard detection systems and avoidance technology safely supports machine operators in the field of mining and construction. Furthermore, there are demands to set standards for machines and systems able to identify hazards, signaling their appearance, and alleviating the risks they present.

There are two current standards in the field, the ISO 16001 standard (earth-moving machinery – object detection systems and visibility aids – performance requirements and tests), and the ISO 17757 standard (earth-moving machinery – autonomous machinery system safety). These standards describe visual aids for autonomous and semi-autonomous machines, but there is no specification relating to hazard awareness and detection concerning human response.

The ISO 21815-2 specification defines the SAE-J1939-based interface between a connected device and mobile machines. The document addresses the collision-avoidance system (CAS) devices, which is integrated independently from the original machine providing intervention signals to slow down, to stop, or to prevent machine motion. The protocol may also be used to present input information for a collision warning system (CWS). The technical specification does not discuss the plug-and-play implementation of CAS or CWS on earth-moving machines. The CAS or CWS manufacturers and OEMs (original equipment manufacturer) need to negotiate the details that are not fully described. The joint working group, 28 of sub-committee 2 in the ISO technical committee 127, is responsible for the development of ISO 21815-2.

There are already other public specifications related to collision detection systems. In the ISO 11992-3, a communication link between truck and trailer is standardized, which provides SAE J1939 messages to indicate vehicles driving behind or in the blind-spot areas of the trailer, and it specifies automated lane departure.

A Comprehensible Guide to J1939

SAE J1939 has become the trusted industry standard and the vehicle network technology of choice for off-highway machines in applications such as construction, material handling, and forestry machines. 

SAE J1939 is a higher-layer protocol based on Controller Area Network (CAN Bus). It implements serial data communications between microprocessor systems (also called Electronic Control Units - ECU) in heavy-duty vehicles. 

The messages exchanged between these units can be data such as vehicle road speed, torque control message from the transmission to the engine, oil temperature, and many more.

A Comprehensible Guide to J1939 is the first work on SAE J1939 besides the SAE J1939 standards collection. It provides profound information on the J1939 message format and network management combined with a high level of readability.

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