Regulations developed by committees are among the factors behind the expanding focus on safety. The committees that create standards are also playing a big role in the effort to improve safety.
There are several standards that help product designers ensure that their systems meet safety requirements, whether those demands are set by regulators or the team members who set specifications for new products. These standards provide guidelines that help engineers determine where they need to focus their efforts while also providing techniques that help ensure that these safety systems will operate effectively.
One of the foremost among them is IEC 61508, Functional Safety of Electrical/Electronic/Programmable Electronic Safety Related Systems, which has an automotive derivative, ISO 26262.
“This requirement has changed many aspects of machine building and the design and development of the electronic and electrical components that go into these machines,” said Kirk Lola, Marketing Manager at Parker Hannifin Corp.’s Electronic Controls Division. He noted that Parker has released one safety controller that meets the specification and has others in the works.
This standard, along with others including ISO15998, uses safety integrity levels (SIL) that help developers provide a level of safety that is related to risks. SIL 1 has fairly minimal requirements, while SIL 3 is very stringent.
“The SIL will drive requirements for single point failures such as failsafe or fail operable. For our equipment, electronic steering over 20 km/h and propel over 40 km/h would be at that level,” said Dan Pflieger, John Deere’s Engineering Manager, Operator Stations.
Companies that supply systems to equipment OEMs implement these standards, but when equipment goes into the field, the OEMs are responsible for the end vehicle’s compliance. Suppliers of hydraulic and other systems note that at all levels, meeting the requirements of these standards is no simple task.
“Safety standards are not for the faint of heart,” said Patrick Babka, Product Portfolio Manager at Eaton’s Hydraulics Group. “We supply the documentation from a certification company, but there’s still a lot of work required at the OEM level to certify compliance.”
As the need for safety and the complexity of safety systems both grow, many companies are involving these certification companies during the design phase rather than waiting until systems are ready to ship.
“For all our safety-relevant products developments we involve the German TÜV as our assessment partner from the very beginning. The functional safety certificate from TÜV proves to us and our customers that we fulfill all aspects of the safety standards,” said Christiana Seethaler, Off-Highway Electronics Teamlead for TTControl.
Though engineers are putting a lot more focus on these assessments, developers note that conventional reliability tests are also becoming more demanding. Electronic systems must help improve overall vehicle satisfaction, not become a warranty and reliability problem.
“As electronic components become more popular on mobile equipment and control more vital functions, the need for testing, validation and certification is greater than ever. Typical tests include electromagnetic interference/electromagnetic coupling, heat cycling, vibration, humidity, and moisture exposure,” Lola said.