[pj_mukh]

Boston Dynamics' primary innovation is in the software/control design. The reason their robots are noisy is because they really haven't innovated a whole lot in the basic actuator design. That's not to say their mechanical design was easy, not by a long shot. It's super impressive stuff!

Any new inventions that would make their mechanical design steer away from loud hydraulics would no doubt be amazing. However, without Boston dynamics' delightfully ground-breaking controls software design, it'll be dead in the water!

For a little bit of proof, see who they are hiring! http://www.bostondynamics.com/bd_jobs.html

[PhasmaFelis]

A lot (most?) of the noise comes from the engine, not the hydraulics, and the engine can't be replaced because sufficiently high-capacity batteries do not exist yet. That's not a problem that can be solved by innovative actuators.

[pj_mukh]

That too. Also engine design was contracted out.

[jarmitage]

Thanks for your reply.

Is there much publicly available information about their software/control design innovations?

Hmm, maybe one might expect they would be hiring more mechatronics engineers to do just that? Or maybe there's still not much point for them because as you mentioned their focus is slightly different currently.

[pj_mukh]

A person with a core Mechatronics focus will probably be a great systems integrator. BD's core workforce are these PhD's in controls (usually from ECE departments). Source: Am a Mechatronics Engineer with a Controls focus.

check out some of the work of BD's CEO (Marc Reibert). This (http://web.unair.ac.id/admin/file/f_7773_bigdog.pdf) is the summary paper on Big Dog, but they cite a bunch of the older Reibert papers on Controls designs for legs.