Four wheel steering (4WS)

[bill shoe]

Good quality information from all, definitely thanks. I am most interested in differential torque as the only means of steering a car rather than as an occasional or supplementary method or as part of an ESC system. This is because ESC-based differential torque just needs to keep the car stable in an emergency, it doesn't need to feel intuitive or good. Steering feel and response need to be very good in order to be a good high-performance control mechanism for human drivers. I don't know if or how this could be done with differential torque. Admittedly, human drivers are a very old-fashioned perspective in 2016.

[wuzak]

Benetton tested a 4ws in late 1993:

http://www.f1fanatic.co.uk/2007/03/22/b ... -steering/

In an attempt to minimise any safety implications the hydraulics were designed to go into a preset ‘fail safe’ position in the event of failure, pointing the wheels straight.

The system was also designed to be turned off and on at will, allowing the driver to run the car with a conventional front wheel steer set up if he preferred.

And in the event that was exactly what drivers Schumacher and Riccardo Patrese did prefer, finding the four wheel steer set up added nothing to the car in terms of laptime. But it did, as far as Patrese was concerned, produce an unusual handling sensation.

The lap times testified that if the system added any to the car’s performance, it wasn't very much. Schumacher said:

"It feels very good, but actually it doesn't change things a lot. I am using the same lines and there isn't a lot of movement at the rear. It makes it a little easier, but right now the system doesn't work very well in the slow corners, so we might not use it in Adelaide."

Apparently Schumacher switched the system off in the middle of a corner, just to see what would happen.

[Thunder18]

Good quality information from all, definitely thanks. I am most interested in differential torque as the only means of steering a car rather than as an occasional or supplementary method or as part of an ESC system. This is because ESC-based differential torque just needs to keep the car stable in an emergency, it doesn't need to feel intuitive or good. Steering feel and response need to be very good in order to be a good high-performance control mechanism for human drivers. I don't know if or how this could be done with differential torque. Admittedly, human drivers are a very old-fashioned perspective in 2016.

I forgot to add the RLX non Hybrid has P-AWS, meaning the rear wheels can toe in independently depending on driver needs.
The Hybrid system uses electric motors to torque steer the car, meaning more power transmitted to the wheels that will enable greater turn speed through the corners. Even the simple mechanical system acted in similar ways.


https://youtu.be/KzQKjQR9u0A

The Ferrari FF also used a similar awd setup