During hip/pelvic thrusting animations whether produced by timeline or Autothruster plugins I run into the same issue. Increasing speed reduces the stroke distance. The problem for me is that I wish to increase the speed while maintain stroke distance and not result in micro humping. Is this by design to prevent physic explosions? I tried difference motions curves but got the same result. While using vinput autothruster I was able to get the result I wanted by making incremental adjustments (cycle duration, distance in and out) with the plugin active. However, as soon as I ran the scene I got the micro humping.