The Olin Snake Project

Overview

The Olin Snake Project was started by Matt Aasted, Gui Cavalcanti, Chris Dellin, Elizabeth Kneen, and Jon Tse due to an interest in snake robotics, sparked by Professor Gill Pratt, and a desire to go above and beyond the requirements of Olin College's sophomore-year Principles of Engineering (PoE) class, taught by Professor Brad Minch.

Principles of Engineering

Sophmores enrolled in PoE are expected to "work in small multidisciplinary teams to design and to build a mechatronic system of their own choosing," reads the description on the PoE website.

PoE provides roughly $300 to each team for material costs and expects students to work 8 hours a week outside of class. However, the nature of our project required additional funding and time, so as a group, we added more credit-hours in the form of independent research at Olin. The Olin Self Study, Independent Study, and Undergraduate Research Board (OSSISURB) provides more funding on a per-group basis, the amount of which subject to need and of course, budget. From OSSISURB and Professor Pratt we received an additional $2000, bringing our total funding to $2300. (This figure includes purchasing of raw materials for next semester.)

Process

Coming into the project phase of PoE, our group had an advantage over our classmates since we began work towards the beginning of the semester, doing preliminary research and component trade studies in addition to the assigned classwork. By mid-semester, when the class had completed the in-class introductory labs, we had completed our trade studies and had our Phase One snake fabricated and undergoing testing. During our initial research we came across a multitude of modular snake designs, where each segment of the snake would be jointed to the next at a fixed location. Rather than repeat the direct-drive solution, we came up with a few unique ideas of our own, and eventually settled on the linkage design presented on this webpage. The design emphasizes the continuous nature of a snake by using an actual spine, in this case, flexible Lexan rod, and using servos and linkage arms to control the curvature of the spine. By controlling curvature instead of joint angle, we feel we have approximated the actual mechanism at work in a live snake, where muscles attached to the ribs control curvature of the spine. By the end of the fall 2005 semester, we had created 4 generations of planar (2D) snake designs. Our final deliverable for our Principles of Engineering class was a 4 foot long, tethered (for both power and control), 4th-generation planar snake (Phase Four).

Instruction

Throughout this process, we had weekly status meetings with Professor Pratt, our OSSISURB advisor. Professor Pratt took a very soft approach to the project. Instead of setting hard deadlines and actively directing us towards specific goals, he took a hands off appraoch, answering questions as necessary and gently steering us away from potential pitfalls. This is not to say that he told us outright not to pursue a course of action, he mainly just smiled and said: "That's great," and let us find out for ourselves. Professor Bradley Minch, who was the instructor for PoE, also took this approach. As part of the class's requirements, we wrote and submitted two progress reports, but the role Professor Minch played was mainly that of a resource we could go to for technical help. This style of instruction allowed us to make our own mistakes and to learn from them, but helped us avoid project-ending failures. If we started going too far down the wrong path they would open our eyes to exactly what we were getting into and give us a soft nudge back into safer territory.

Future Plans

Now that we have a firm grasp of the mechanical, electrical, and control design challenges of working with robotic snakes, we will continue our research next semester by investigating three-dimensional, completely untethered robotic snakes.