Do Robotic dogs have a leg to stand on?

Fascinating video of the DARPA/Boston Dyamics legged robot walking independently.....



I'm interested mainly because it has 4 legs, not 6. The initial thinking behind "proper" walking robots was that they would be 6 or 8 legged, since insects / arachnids require less computing power to use 6 / 8 legs than higher order animals need for 4. Also, 4 legs has no limb redundancy. For those who follow the development of robotics, here is a simple summary of leg from MIT's work on planetary surface explorers - the "Little Martian Robots" (LMR's)

2 Legged LMR
Many bipedal robots have been designed. For a selection of some of these intriguing machines visit the MIT Leg Lab Website. It is conceivable that these robots could be designed to be stable without the need to stay in motion. The martian surface, however, will not be particularly flat making bipedal balance a fairly tricky issue. Also, the Martian winds and weather would make it difficut for a bidepal robot to stay standing. Should one of the legs break, the robot would become an imbalanced mono-legged rover. Such a robot would be incapable of balancing whether in motion or in stand-by mode.

4 Legged LMR
4 Legged LMR Quad-legged robots like the Leg Lab's quadruped, have more realistic leg configurations. It is fairly easy to balance a four legged robot, even on a fairly irregular surface. The rover would be capable of motion across the Martian landscape and would have the ability to stop and remain standing. A four legged LMR, however, would not be very rugged. Should one leg break, the robot would find itself imbalanced and fairly incapable of moving. Indeed, a three legged rover would need to be programmed in an entirely different way than a four legged rover, making it necessary to include a separate control program in a case a leg were to break off.

6 Legged LMR
6 legged LMRs like the MOBOT Lab's Hannibal and Atilla are more realistic models of legged motion. The success of the Hannibal and Atilla prototypes clearly show that a 6 legged LMR would be capable of functioning on the Martian surface. It would be capable of balancing well, even with strong winds and the Martian dust storms. The LMR would also be capable of sustaining itself even if one or (under certain circumstances) two legs were broken. There would be no need to completely reprogram the LMR as the models of motion for a six legged LMR and a five legged LMR are very similar.

8 Legged LMR
8 legged LMrs would allow for the greatest usable level of redundancy on the LMRs. It is conceivable that the LMR could continue functioning if up to four legs are broken. This should give the small LMRs the capability to stay out in the field for longer periods of time. A more important use of the extra two legs of an 8 legged-LMR exists however. It would be possible to use any pair of legs as a proximity detector (Angle and Brooks, 1990 "Small Planetary Rovers" ONLINE). If the leg were to brush against anything, the LMR woulld be capable of noting that it is close to an external object. In this way, the safety of the LMR in-motion can be gauranteed with more certainty. It could also be possible to carry sensors of some sort on the non-critical front two legs. Indeed a whole variety of options are opened up in having an 8 legged LMR.

We have chosen that our small LMRs use the 8 legged system over a 6 legged system for the above reason.

A remembrance in the week of Arthur C Clarke's death - I was one of those kids of my generation fascinated by (i) Space Travel and (ii) Robotics, and thus especially space travelling robots. However in the 1980's when I did my BSc and MSc Engineering degrees, the computing power and various associated tech. (eg battery power) required to make these things work just was not there (My final year design project was a robot btw) - it was sadly clear that we had to wait quite awhile, so I turned my interest to the emerging networked computing field. In the 1990's we also saw the emergence of Evolutionary algorithms, Neural networks, fuzzy logic etc which have really pushed the capability of self-controlling automata

(Thanks to LLoyd Davis for link)