1. When playing with active suspension, we used warp offset to turn steer angle, with other measurements, into a "trajectory" demand. It worked well, improving the cornering performance. I have described the control law, and shown video evidence of the effect, elsewhere in F1T.
2. It is not well known, perhaps, that we added rear steer to some active vehicles. That also worked well when driven by a version of the same control law. Interestingly, in a turn, the rear steer angle moved quickly to increase the yaw rate, and then returned equally quickly to (close to) zero as the turn developed (not good for rear passengers, because the initial acceleration was in the wrong direction).
3. The rear dampers on an oval car are often set with compression digression on the left, and rebound digression on the right (the cars only turn to the left). I was told that set-up gave the drivers "confidence", but I interpreted it as giving the vehicle turn-in oversteer, hopefully backing off as the turn developed.
4. I devised a rig test procedure in an attempt to quantify the effect. We discovered that many of our "optimal" set-ups resulted in turn-in oversteer, but not always. We thought that roll center heights might have had an effect, but had no way of measuring them on a simple rig...
An extract from a previous post stated:
I was happy with Lycoming's comment, and his explanation. Tim commented on the size of the delay caused by the geometry. My immediate thought was the effects of damper "shape" would also be small, but it can have a significant effect on cornering performance.... according to my observations.Tim.Wright wrote:Not meant as a personal dig, but that sounds like just another cult saying. The sooner people move away from religious, hand-wavy explanations and use proper physics then the discussion can move forward. I think also a lot of people would be disappointed with how small the delay is between the geometric load transfer and the elastic load transfer, especially on stiffly sprung race cars.Lycoming wrote:I was always told that this was done to make weight transfer happen more quickly at the rear to allow the rear to "catch up" to the front during turn in.Tim.Wright wrote: Rear roll centres should be higher than the front because the "CG axis" of the car is inclined up towards the rear
So why am I interested? I would like to understand better the "physics" of the turning maneuver and develop our test procedure into a more useful tool. Hence any reference to Lycoming's explanation would be useful. It might be useful to know Tim's production cars that do not follow the trend.
BTW, perhaps anticipating a response from Greg, some engineers do not like (relative) turn-in oversteer on a road car....