Three legs (at any given time) are better than any other number
Blogging has been at the bottom of my list of priorities as I adjust to my new research institution this month. Add a week away visiting colleagues in Paris [yeah, I’m adding this just for bragging purposes] and you will understand the lack of posts.
In the past couple of days I have been doing some background literature research on the topic of insect walking. What I did not know is how big this field is compared to other topics in entomology. The reason behind this popularity is, unsurprisingly, the fact that the results of such research have a direct technological application: robotics. In particular six legged robots or hexabots (they should be called something like hexapodbots, but I guess the shorter name is cooler).
There are simple good reasons to go for six legs if you want to design a walking apparatus. Think on how many times when you go to sit down at the coffee shop you spend the first couple of minutes folding whatever piece of paper or cardboard you find around in order to place it underneath one of the legs to stop the four-legged table from wobbling. But you never had to do that for three-legged tables. That is because three legs are just the right number to stop whatever they support on top from moving in any dimension. Take one leg out and your table will fall following a straight arch path. Add one leg and your now four-legged table has usually more than one way to rest on three supporting points. Three legs is the most stable arrangement.
OK, but why six legs then? Because with that number you can always leave three legs firmly on the ground while you move the other three, which makes for a very stable walking. One in which the body can be kept at the same height plane while traveling forward, something insects do most of the time while walking.
Most of the research on insect walking uses stick insects and cockroaches as test subjects, and involves putting the animals to walk on treadmills to observe the pattern of leg movement under different conditions of speed, inclination, etc and, for example, immobilizing (our cutting) one or more legs to see how the movements are adjusted. A big part also involves figuring out the nervous circuitry responsible for coordinating all those legs.
I have to say, it is all fascinating and cool, but it is useless cool for what I am interested in that is, you guessed, leg anatomy and simple biomechanics (what muscle moves which skeletal piece). At the end I realized that going back to basic comparative anatomy is all I need for now. And for that Robert E. Snodgrass never fails me.
Don’t expect this blog to pick up in speed anytime soon though, but I’ll keep you entertained from time to time dear readers.
