The Legs

So, I've spent some time looking at pictures of tortoise skeletons on the Internet, reviewing servo prices, and learning about existing robotic designs and I've come to a number of important conclusions regarding my project. 

1. emulating the structures of vertebrates has the potential to dramatically  increase the complexity, so I will need to think creatively to make this work.  

2. depending on their intended purpose, robotic parts can be extremely expensive, so I will need to keep my mind open about what I use for supplies. 

3. tortoises have far more complex necks than I ever would have thought.  Just look at the skeleton drawing (above) I found on tywkiwdbi.blogspot.com and the photos (below) I took of tortoises on the Galapagos Islands.   

A Galapagos tortoise with its neck in a partially retracted, relaxed position

Another Galapagos tortoise with his neck extended. 

Although the prospect of building my own robotic tortoise has become somewhat more daunting, I have managed to stumble upon a prospective design for the tortoises legs, which were largely inspired by a very cool design for a 6 legged hydraulic robot (below) by "Crazy Eyes" that I found in 3D Warehouse. 

Using the parts and mechanical ideas from Crazy Eyes' robot, I managed to create a model in SketchUp that may be able to approximate the movements of a tortoise (below). 

My tortoise adaptation of Crazy Eyes robot. 

In my adaptation I replaced the hydraulics with servos and moved the legs to the bottom.  I also added a large gular projection ahead of the front legs, twisted all legs forty-five degrees backward, and angled the front legs so they were closer to the gular projection.   

My next task, which will be far more challenging, will be to design the robots neck.