In a previous message I mused that gravity can be such a nuisance to the wishes of robot builders, especially those who build walkers, and how low-gravity environments could be handy.
After I sent the message I ruminated some more in that vein. The only practical ways I know to reduce effective gravity here on Earth -- specifically on the ground, not in a flying aircraft -- are using counterweights, using inclined planes, or operating in a fluid offering neutral or slightly positive bouyancy.
Inclined planes might be of some use for my purposes (i.e. sculptural displays), provided I had a way to make my robots cling to the tilted surface so they wouldn't slide down the slope, yet do so in such a way that didn't hinder their movements on the plane. Tricky.
Counterweights (or balloons, for that matter), could work, but they would be all wrong aesthetically. Balloons would block the view, and suspending wires would inevitably get tangled up with each other. Even if these troubles could be satisfactorily sorted, visible wires would make people think, at least on a subconscious level, of puppets, which is counter to what I'm working to achieve.
Buoyancy, though, has some possibilities. With the right ballast, BEAM robot walkers operating in a clear, electrically non-conductive fluid could use such feeble actuators as voice coils to move leg segments. The movements would be rather slow, depending on the power available and the viscosity of the fluid.
Distilled water might work, assuming low-voltage motors would still operate. I know Boeing has used distilled water to cool slip rings for low-level instrumentation signals, so brush-commutated motors should be fine on that score. The viscosity of the water might play hob with the rotor friction, though.
With a downward-thrusting propellor, a new sort of pummer might be possible, one that floats placidly near the surface while charging, then does mad little dives to the bottom until it's charge is gone, whereupon it floats back to the surface. A Cartesian Pummer.