Earlier we reported that SIGGRAPH 2010: Emerging Technologies would host a playful French robot called Acroban, and now its developers at INRIA Flowers have updated their website and have plenty of videos to watch on their official YouTube channel.
Acroban is an exciting example of what is possible using commonly available parts and a lot of ingenuity. It has 30 degrees of freedom actuated by Robotis RX-28 and RX-64 servos, and its base materials are aluminum, elastics, and springs. Some of the team members had previously built a comparably low-budget humanoid called Rho-Ban, and have worked with NAO and SONY’s AIBO.
Uncommon among most humanoid robots, its spine has 5 joints alone, as well as springs and elastics, which help to dampen the effects of unexpected external bumps and knocks. They’ve programmed the actuators to dynamically relax when sustaining external forces. This allows you to physically influence joint positions with almost no resistance.
Indeed, Acroban’s mechanical structure informs its movements and provides a degree of stability that encourages the spontaneous physical interactions of a child. Led around by the hand, it keeps step with simple dynamic walking. Placed at the top of a ramp, it automatically begins walking down the slope while maintaining its balance. You can push and pull it around and it regains its natural composure. It successfully shrugs off bumps from a ball thrown at its upper body that would turf most of the RoboCup Humanoid league. The following video is a little long, but well worth watching to see this in action.
Interestingly the researchers note that despite Acroban’s minimalistic metallic frame, it engenders positive feedback from those who interact with it thanks to its unexpectedly lifelike physical responses. They’re calling this the Luxo Jr. effect, from Pixar’s lovable hopping table lamp. Although I suppose it would complicate the body mechanics and calculations, one can only imagine the response it would get with a friendly exoskeleton.
It’s great to see such a competent robot built out of (relatively) inexpensive components. The design of its body, particularly the attention paid to the spinal column, and the inclusion of springs and elastics, deserves the attention of robot labs around the world. Of course, I would love to see Acroban get a proper head and body, even if it does fine amongst the kids without them.
More in-depth details, several fascinating videos, and the paper from SIGGRAPH 2010 are but a click away at the source link below.
[source: Acroban @ INRIA Flowers]