Symptom: Unwanted Wheel Oscillation

Dominic BrennanDominic Brennan Member, Administrator
Wheel oscillation typically manifests itself as a rapid 'rocking' from side to side, typically when driving at medium to high speed on a straight. In severe cases, the oscillation can be felt while gripping the wheel, and in less severe cases it is only apparent if the wheel is released or held very lightly.

This is NOT a fault, nor is it unique to Fanatec products. It is an inherent characteristic of typical force feedback signal output, and can become more apparent with more powerful wheel bases with low internal resistance, as the rapid response of the motor and its inertia causes an 'overshoot', which is then 'over-corrected', ultimately resulting in a feedback loop. There are many variables that can contribute to oscillation, including the sim software being used, the platform (PC or console), the overall latency, the Tuning Menu settings, the in-game settings, the vehicle and track combo selected, the vehicle setup, and so on.

Many racing sims have built-in compensation for this, but sometimes it requires some additional settings adjustments to reduce the impact. The main way to reduce oscillation is through damping. Note that the reason why oscillation can increase when you let go of the wheel is because your hands are effectively acting as a damper. There is a 'DPR' setting in the Tuning Menu of all wheel bases which can have an effect, but this is set to 100 by default and relies on appropriate use of the DPR feedback modifier within the game engine, and this signal is often left unused by developers. More significant is the DRI (Drift Mode) setting for our belt-driven wheel bases, as this is operates independently from any game signal. Lower values of DRI increase the strength of the electronic static damper, which helps to reduce oscillation. In our direct drive Podium Series bases, we do not use a Drift Mode, but we do have a Natural Damper (NDP) that achieves a similar effect of increasing amounts of damping. In addition, the Podium Series has a Natural Friction (NFR) setting that can also help to reduce oscillation.

More recent Podium wheel base firmware has also introduced a Natural Inertia (NIN) setting that can also help to reduce oscillation (it helps to reduce the chance of oscillation starting, but can potentially increase the oscillation once it is going).

The FanaLab software (PC only) features a Dynamic FFB system with Speed Sensitive Damping. Because this works directly from game telemetry, it is very effective at reducing (and with the right settings, completely eliminating) oscillation. Using the Speed Sensitive Damping in FanaLab gives an opportunity to lower the values of the standard (non speed sensitive) damping filters, potentially allowing more FFB detail to come through at lower speeds.

As long as the oscillation is manageable with settings, it is not considered to be 'bad' characteristic - in fact it demonstrates that the FFB output is very communicative on centre, the opposite of having a 'dead zone'.

Comments

  • Nicely explained, i have the csw 2.5 running 100 damper and -1 dri and still if i let go the wheel it will oscillate on AC. I have noticed that other manufacturer wheelbases dont have that, or it appears to be minimal. There are online videos of people driving without even touching the wheel, which would be impossible to do with mine without having it oscillate. So i guess this is a ffb feature but with custom software adjustment it could be eliminated.

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