One of the many things that makes humanoid walking tricky is the fact that when we walk, we’re off balance almost all of the time. For some silly reason, our legs are positioned to the left and right when we spend most of our time walking forwards, which means that walking means constantly rocking sideways while also leaning in the direction we’re going. Most robots don’t try to walk like this, and the few that do tend to be very complex and difficult to manage.
At UCLA, Dennis Hong’s Robotics and Mechanisms Laboratory (RoMeLa) has come up with a robot design that’s a novel new take on bipedal walking. By doing away with anthropomorphic design and turning a humanoid robot sideways, they’ve been able to create a stable and agile bipedal design that’s simple and cheap at the same time.
“Instead of mimicking human walking,” Hong told us, “we provide an elegant solution by proposing a novel configuration utilizing ‘mechanical intelligence’ for speed, stability and simplicity, enabling practical and effective robot mobility for real life applications.”
RoMeLa has been developing very humanoid-y humanoid robots for years, including DARwIn, CHARLI, SAFFiR, and THOR. All of these are traditional humanoid designs, which try to mimic the overall shape and capabilities of humans as closely as possible. The reason to do this is because (some people argue) we’ve designed and optimized our world for us, and so for robots to be able to do everything we need them to do, they’ll need to do what we do, how we do it. This was a big part of the idea behind both ATLAS and the DARPA Robotics Challenge, although it’s worth noting that of the three top finishers, two of them had wheels and one of those was also a quadruped.
“Humanoid robots are still too slow, too unstable, too expensive, too complicated, and too dangerous,” Hong says. “I do not believe humanoid robots will be able to be used mainstream any time soon.” With that in mind, the options are somewhat limited if you need a robot that can do human-type tasks in human-type environments, which include (among other things) climbing stairs and walking across uneven terrain without constant fear of falling over.
Apparently, once Hong and his students (including Sepehr Ghassemi, Jeffrey Yu, and Joshua Hooks) came up with the concept for a sideways walking robot, designing, building, and testing the robot only took two weeks. NABiRoS stands for “Non-Anthropomorphic Bipedal Robotic System,” and its non-anthropomorphicness actually makes it better at navigating some otherwise tricky human environments. Specifically, the researchers are hoping that adding a rotating knee will allow NABiRoS to easily climb stairs or climb through the kinds of doorways with high sills that you find on Navy ships (RoMeLa’s firefighting humanoid SAFFiR had a lot problems with this).
It looks like NABiRoS’ biggest problem at this point is that the current configuration, while is able to move in straight lines quite well, doesn’t have a good way of either rotating or translating to the left and right. The end of the video includes some hints as to how this might be achieved, and Hong also mentioned that RoMeLa is working on another robot called ALPHRED, a sort of cousin to NABiRoS except with four limbs that walks in a “different and interesting” way. I’m sure that’ll become clearer when Hong reveals what the acronym stands for.