Jumping Robot Salto-1P Now Goes Where You Tell It To
Nice. I used to work on that problem, because I was into legged running for robots and animation. Rather than putting fans on the &quot;torso&quot; to provide torques, I was doing that by having a leg with three joints and coordinating them to apply torques to the torso.[1] This is how far I got. (Video, generated on a Mac IIci. Hours of run time for seconds of simulation.)[2] I notice the Berkeley group is using three joints, too. They should&#x27;t need those fans to exert side forces.<p>The real objective was to be able to handle running on slanted surfaces. That&#x27;s all about slip control.<p>I looked at this as a two-point boundary value problem with an underactuated controller.  You want to get a specific orientation, angular rate, and target position at landing. You have more target variables than you have actuators. You don&#x27;t care too much about the intermediate states as long as the state at landing is what you wanted.  That&#x27;s rocket science. Which is good, because rocket trajectory control is a well understood problem.<p>Once you start solving this as a boundary value problem, you can make much more aggressive moves. Going way off balance to get a fast change of speed or direction is fine as long as the next landing is within bounds. Most running robots today start out running in place and slowly accelerate forward. They don&#x27;t start by leaning forward and launching. That&#x27;s because they work by trying to maintain a stability criterion. In slow robots, that&#x27;s static stabiilty - CG over base. Faster ones use &quot;ZMP&quot;, which is a generalization of static stability which adds a momentum term.<p>There are newer approaches, and the most recent Boston Dynamics robots are going into unstable positions to do things like flips, then recovering to a stable position. That&#x27;s looking one move ahead. If you can look two moves, or footfalls, ahead, you get much more agility. Some of martial arts and dance is learning sequences of three moves ahead. That&#x27;s an athletic feat.
You need two moves ahead to do broken-field running or the stop by turning that horses do, which is within the normal range of ability.<p>Fun problem, but decades later, still no market.<p>[1] <a href="http:&#x2F;&#x2F;www.animats.com&#x2F;papers&#x2F;articulated&#x2F;articulated.html" rel="nofollow">http:&#x2F;&#x2F;www.animats.com&#x2F;papers&#x2F;articulated&#x2F;articulated.html</a><p>[2] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=kc5n0iTw-NU&amp;feature=youtu.be&amp;t=104" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=kc5n0iTw-NU&amp;feature=youtu.be...</a>