Comment by MoonGhost

> Stop the arm and you'll break off the teeth on your gears!

Unless you have some energy dumping mechanism, like connect your servo to arm with flexible connector. Making whole arm or leg with bit flexible plastic will also reduce max load on gear. Precision will suffer, but should be still good enough for walk and house work. The problem with energy is that it should be undone when direction changes. This affects reaction time. And that time should be smaller for small, a... proportional to square root of size, right? That's how long it takes to fall. Not sure, didn't take into account the inertia of solid body.

BTW, heavily geared humanoid robots walk in some more stable way on bent legs. This is obvious on old videos. Like they are afraid to sh*t their pants. Also have problems with balance. Small hobby robots usually in addition to bent legs have huge feet. The point is, with servos it cannot be done much better.