My sewing room has carpet. The shelf liner doesn't work and I didn't want to use Velcro because I was worried it would ruin the carpet fibres. So I bought a set of those rigid plastic pieces that have multiple pegs on them, they're meant to keep the weight of furniture off of carpet. The ones I bought were square and had a peel and stick surface - I mounted two on the underside of my foot control. I also turned it around as suggested, front to back, and it rarely moves much at all now.
