I'm working on the design for an 18-servo hexapod. I've built one leg to test my gait control and inverse kinematics code; that leg uses three digital servos driven by a Mini Maestro 24-channel controller. So far, everything's gone well, but I have concerns about powering the final 18-servo hex.
Right now, I'm using a Pololu 5V/9A buck converter (connected to 3-cell LiPO battery packs) to provide servo power to the Maestro, and it works fine with three servos. I'm worried, though, that 9A will not be enough to drive all 18 servos (plus maybe two more for a tilt/pan mount), particularly under load. The digital servos draw 500mA when running under no load, and about three times that much when stalled.
One way to go, I guess, would be to create modular systems, e.g., a 12-channel Maestro w/ dedicated power converter for each of two groups of three legs. I'd rather not do that, so I'm wondering what options there might be for sticking with a single 24-channel servo controller. Has anyone ever connected the buck converters in parallel? If so, what sort of external circuitry is required?
Not all 18 servos will be moving at once, so maybe 9A turns out to be enough, if only barely. But even in that case, I'd like my design to have a bit of headroom.
I'd appreciate any thoughts you have.