Integrated mechatronic systems open doors to better diagnosis and better control of actuators. The combination of power line communication (PLC) and distributed computing offers a smart and low-cost method of in-car subsystems power management. The implementation of a robust PLC protocol allows drastic harnesses weight reduction. Here we describe the practical implementation of distributed power management in seats, doors and lighting subsystem
Car electronic architecture
In today's vehicles, adding a new function in the pre-existing electric/electronic architecture (EEA) is often accomplished by the incorporation of one ECU connected to its own sensor & actuator components. The increasing number of ECUs in vehicles becomes critical in term of integration into the vehicle since available space for electronic is no longer maintained. In term of complexity it also leads to an increase of wires, communication networks, energy management and so forth. Thus disruptive solutions are required to reduce numerous wires & ECUs and to optimize energy consumption. The introduction of PL? in the vehicles combined with increased use of mechatronics is a possible solution.
Components vs. wire harness
For a middle range or C segment vehicle we can consider a total of 35 embedded ECUs, 20 ECUs for the power train, chassis, and HMI and multimedia domains. For the body and comfort domains, 15 ECUs are implemented within around 100 sensors and actuators. Some components integrate an electronic module within a mechanical part forming mechatronic modules.
Regarding the diversity of actuators, we consider using the PLC solution on the small and medium actuators which are used for mechanical movement in the door and seat areas where, for the sensors, the electronic characteristics do not impact the PL? solution and mechatronic size. Indeed, the range of the average current for these actuators is from 1 to 10A with a maximum inrush current of 25A in few cases. The command is either very simple or uses a low frequency pulse-width modulation. The response time of these functional systems is around 200ms within a sensor signal response in the range of 20 to 200Hz maximum.
The wiring harness in this body and cockpit area can account for more than 700 wires which means more than 1.3 ,km of wires, 1400 connections, and 25 kg mass. For instance, the driver door can integrate up to 50 wires for the locks and the contacts, the anti-pinch window lifter, the mirror, the control panel, the several lights, the free handle system, the loudspeakers, etc. The number of wires in an electrical seat reaches a similar level. Thus the body and cockpit area offers a great cost reduction opportunity for power line communication especially in door and seat sub-systems.
For the complete article, which looks at reliability and safety; configuring a real-time PLC network, and sensorless control, click here, courtesy of Automotive Designline Europe.
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