Hey, rojohound. The .capx above is an exemple from "[How do I]Frequently asked questions" that I've modified a bit. I searched for other exemples but I haven't found something to mach what I need.
However, I played with the speed of the player and box (player speed is now a bit smaller than the box's speed) and it seems to work much better. It's still vibrating but much rare and with less intensity.
Here is the link: https://www.dropbox.com/s/gj973pa5a84tr ... .capx?dl=0