This is a combination of designs that I've modified a lot and will eventually get round to combining. I haven't given it any power yet or a micro, but the idea is primarily to have it randomly patrol an area, grab anything it bumps into, and then run back with it to a fixed location.
It uses 2 x SG90 servos to waddle around, another SG90 to act as a claw and a fixed position SR04 as echo location.