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Performance requests and machine automation, in conjunction with new regulations for commercial and heavy duty vehicles, represent a difficult challenge for machine design. Machine control systems complexity and functional safety regulation, are complex requirements to deal with in new machines design. The paper describes a steering system design, of a 6 wheeled agricultural front articulated self-propelled machine, that must comply with new regulations in terms of functional safety. The vehicle steering is driven by an electro-hydraulic system, totally controlled using electronics; the rear wheels are independently steered and controlled. This architecture requires a highly functional safety performance level. The safety analysis of the system lead to a required performance level whose compliance is a challenging task, due to the software quality required, and to the cost of a fully redundant hardware, on both electronics and hydraulics side.

Functional safety requirements and solutions are more expensive when it comes to lower cost machines with less power but same functionalities with respect to big machines. The paper will show a real Electronic Control Unit (ECU) design of a machine controller, controlling both engine working point, transmission, and other utilities like PTO, 4WD, brakes and Differential Lock; the ECU was designed in accordance to ISO 25119 regulation, to meet AgPL = C or even D for some functionalities. The unit is a fully redundant electronic control unit with two CAN networks and some special safe state oriented mechanism, that allow the Performance Level C with less software analysis requirements compared with traditional solutions. All safety critical sensors are redounded and singularly diagnosable, all command effects are directly observable and most of commands are directly diagnosable.

Ethernet is by now the most adopted bus for fast digital communications in many environments, from household entertainment, to PLC robotics in industrial assembly lines. Even in avionic applications, new standards are fixing research results. In a similar way in automotive industry, the interest in this technology is increasingly growing, pushed forward by much research and basically by the need of high throughput, that high dynamics distributed control requests. In the world of heavy-duty machines various needs suggest to investigate for a possible Ethernet Network implementation for both real time control and services. On the other hand Bosch proposes the FlexCAN, CAN Flexible rate, but it seems a short term solution for today's congested networks.

Heavy duty machines have become more electronically sophisticated and in-vehicle electronics are growing in number and complexity, keeping pace with technology advancements. New machines implements (both mounted or trailed) and machine automation, demand this evolution, and thus a new way of designing on-board Electronic Control Units (hereafter ECU) is required. Moreover, the connectivity between vehicles, often extended to World Wide Web, and machine control and Working Session Task Controllers demand to become really distributed and executed in real time. So, integrated control systems ask for more performing distributed controls over networks, in order to better manage the machine torque and power and in order to optimize the fuel consumption, as a function of power request.