Steering system integrates safety

An intelligent steering option incorporates both a steering and a safety controller into an electrohydraulic actuator, saving development resources and accelerating time to market for OEMs across agriculture, construction, road building, material handling and specialty markets.

The system connects directly with GPS to allow automatic steering for an array of off-highway machinery—including tractors, combines and sprayers. It also improves driver comfort with “Quick Steering” functionality and enables joystick or mini wheel steering for all applications. Previous steering systems used an external safety controller to monitor the electrohydraulic section of the steering valve.

The OSPE with PVED-CLS actuator option is part of the Danfoss Functional Safety Solution. Designed with the safety of machine operators in mind, the flexible software-based system comes preconfigured with a number of steering-specific safety functions informed by comprehensive safety analysis and customer research. It can be easily adjusted to meet the specific output and safety requirements of each application. It also includes integrated electrical follow-up (EFU). EFU aligns the steering wheel with the tires to ensure precise, unwavering drive trajectories. With this automation comes easier operation, higher productivity and reduced driver fatigue.

DanfossWith PVED-CLS, system designers no longer need to ensure that multiple parts are communicating. Now that the PVED-CLS is in direct contact with system pressure and feedback from the LVDT transducer, the operator is able to react more quickly and accurately than with an external controller. When it comes to safety, this fast and precise reaction is crucial, and the tight sensor coupling also means less machine downtime and fewer false alarms. In case of a fault, the monitor gives operators manual control within the electrohydraulic safe state.

In addition to improving functionality, the integration of the safety controller into the steering unit reduces the system complexity.

The OSPE with PVED-CLS is certified by TÜV SÜD, the German safety validation organization, for functional safety of electronic equipment (SIL2 for IEC 61508) and functional safety of control systems (PL d, ISO 13849 and AgPL d for ISO 25119 [EN 16590]).

The PVED-CLS hardware is based on a fully redundant Category 3 system architecture. The system takes care of steering hazards off road. Additionally, the PVED-CLS has received the “E-mark” stamp from VCA (the United Kingdom Vehicle Approval Authority). The “E-mark” is a general certification regarding EMC (directive ECE R10), which OEMs can use toward final vehicle homologation.

Danfoss Power Solutions

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