Nissan's next-generation steering employs a steering angle sensor at the steering wheel, three ECUs for control, electric motors to power the rack, and a steering force actuator near the driver to retain the vehicle's "steering feel."
Greg, the backup is absolutely required. While it is rare, I have been in a car where the power failed and the power steering stopped working. This was a hydralic system, and it was very hard to steer the car, but at least it could be done. Electrical systems are more likely to go out on a car, I would venture to guess, than the purely mechanical ones. Especially electrical systems that are digital.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.