The above photos show the pictures of the 2 prototypes we made before making the actual snake. The 1st prototype was made from PVC pipes mainly to experiment with the circular cross-section. But after looking at the results, we found out that even a small unbalance in center of mass or inertia would cause the robot to roll away on the ground.One of the mistake made by us was mounting all the servo motors on the same side of the link we should have mounted the servos such that the consecutive axis are 180 degrees apart from each other.
Hence we made a second prototype out of aluminium keeping a square cross-section and this time we gave alternate Pitch and Yaw degree-of-freedom to each link as compared to the earlier design where the axis of rotation of all the joints were parallel. We successfully achieved the side winding motion in this prototype and hence we made our final robot on the basis of this design.
These prototypes were made to test out algorithms and hence have a off board supply and control unit. In the final robot everything was made on-board.