MakerBot Replicator 2 first designs for a re-configurable robot with hierarchical and combinatorial sensorimotor contingencies.

Design criteria for a Hierarchical Re-Configurable Robot. 

1. The body should consist of a small number of module types e.g. 2 types that can attach into each other in a small number of ways e.g. 2-3 ways.
2. At each connection (joint) there is a certain DoF, e.g. rotation (ball-socket) etc...
3. Each module contains 1 motor that can power one of these 3 possible joints, but only one.
4. Each module can attach a variety of sensor types, but only 1 sensor per module in up to 4 positions.
5. Wires pass through the modules, and out of a base module to the arduino.

This means, if there are N modules, there are 3^N possible configurations of modules. Given M sensors per module this is 3^N^M different sensorimotor contingencies.


Possible shapes for a module

1. Ball and socket, requires multiple muscles to guide motion (not suitable here)
2. Hinge joint (elbow) Requires extensor and flexor (or passive sprung flexion)
3. Saddle joint.
4. Pivot joint

How is it possible to permit a range of joints on the same module, each operable by the same motor? How did Hod Lipson do it, always a sensible question to ask. Here

Other examples of reconfigurable robots here...

http://www.youtube.com/watch?v=8XP1q6ph7sU [mmmm, boring]
http://www.youtube.com/watch?v=6tD3dsDzbeg