User:Patrick Thor/ENES 100/Project 3(Strandbeest)

Write problem/project Goal
To construct a standard hand powered StrandBeest made of PVC piping and wood that walks on the ground.

My First Task
Research into the progress of other groups at HCC, see if I can salvage any information or parts from previous attempts. Work with Derek to decide what materials we want to use, and maybe start fabrication and design.

Summary of actual work over first weekend
Researched into prior groups working on building a strandbeest along with researching how to build and defining the physics behind it. Did some research into materials to decide the best and most cost effective way to complete this goal.

Week1 Narrative
(November 12th, 2012)


 * Was assigned the project of the Strandbeest today. Met with my partner, Derek to discuss what goals we would set for ourselves. Looked into some other groups at HCC who had previously worked on this project, however did not find a group that had successfully completed it. Derek and I went down to the parking garage to get some CNC cut wood that a student at HCC had previously cut to make a strandbeest but he had never finished.

(November 14th, 2012)


 * Met with Derek today in class, and we defined our final goal and our problem statement. Still not sure what to use as for materials, will hopefully by the end of the week. Found many Strandbeests in research that had used many different types of materials.

Some possible contenders for our Strandbeest include:
 * K'nex
 * Wood
 * CPVC
 * PVC


 * I wanted to fully grasp the physics and mechanics behind the strandbeest so I began looking into some explanation and simulation regarding them. Through this I found there are many types of strandbeests, however after speaking with Derek, we decided to do the basic, original design of the stradbeest. I found this video showing the mechanics of the strandbeest extremely helpful in picturing our design in my head.

https://www.youtube.com/watch?v=NM4q-f68TlY
 * I also looked into the different materials on our list to try and decide which was best. K'nex seem to be too expensive for our needs, and we do not have the right tools to produce precisely cut wood pieces. I found some local retailers who sell CPVC and PVC for cheap, so Derek and I will hopefully go check out that at some point this week.


 * Found a explanation from Theo Jansen the man who created the original Strandbeest. He also goes into detail and explains the exact proportions needed to produce the legs at 100% efficiency.

http://www.strandbeest.com/beests_leg.php

(November 16th, 2012)


 * I went to a local retailer and found a lot of PVC pipe and joints that we should be able to use to achieve our goal. Spoke to Derek and he had bought some and started fabricating it. Just need to figure out if the weight and the friction will cooperate.

My Second Task
The next step is to test to see if the weight of the PVC and the friction between the pieces will allow for the Strandbeest to work, if so continue fabricating it with PVC. If not go back to the drawing board and test another material.

Summary of actual work over second weekend
Due to the holidays and my absence from town I did not get as much work as I had hoped to get done this week. Even though we decided to use PVC as our main material of choice we found that fabricating and sizing it correctly to match the "holy numbers" from Theo Jansen's design proved to be a challenge.

Week2 Narrative
(November 19, 2012)
 * Much of this week was spent going back and forth with my partner Derek and discussing our plans and number crunching. Using the length of our PVC crankshaft we were able to come up with the proper numbers that match the proportions produced by Theo Jansen's design.


 * At this point I still have not decided how long the crankshaft should be to accomodate this design and these materials. This is something I need to talk to Derek about.


 * While there is a standard and proper proportions to Theo Jansen's leg, there are several variations in how you connect the legs. One way is a triangle "bridge" where there is a central bar at the top that forms the triangles point, and the legs are in between the ruts. The other way is a simple rectangle design, where 2 bars extend the full length of the strandbeest and are rigid.


 * We plant to build using the rectangle design, however the triangle design is still in the back of my mind for later reference if needed.


 * I also found an interesting tutorial for building a strandbeest, however the materials are K'nex, but the design portrayed in the tutorial are extremely similar to what I would like to fabricate.


 * http://www.instructables.com/id/Knex-Strandbeest-Walker/?ALLSTEPS

My Third task
Finalize the design, and fabricate/test the legs. Also need to figure out how we will cut the pieces needed for the legs. The cuts must be very precise or the mechanics will be off. Derek may have access to a CNC cutter that we can use.

Summary of actual work over third weekend
Bought all the necessary PVC and particleboard needed to finish this project. Began cutting and fabricating the pieces using a table saw.

Week3 Narrative
(November 26, 2012)
 * Finalized our design and sketched out the final leg measurements and dimensions. The crankshaft is still being made using standard 1/2" PVC, the legs will be made of particleboard and jointed with PVC, and the frame for the crankshaft and legs will be made of standard 2x4 pieces. Derek had calculated the proper measurements in centimeters, to make everything consistent, I converted these measurements to inches. I brought some pieces of particle board and drew out all the necessary pieces on a piece of particleboard. The engineering room does not have the proper, precise tools we need to cut out the pieces however so those will have to be done using Derek's table saw at his house later this week.

(November 28, 2012)
 * Changed some things with the design of the leg. I planned on using singular pieces for all the lines of the leg, however found it would be easier to joint the legs together if we made too triangles instead of using single line pieces to connect them. The triangles that I referred to can be seen in the sketch to the right, they are triangles EDB and JHI. Needed to find the proper angles of the triangles though however, so using the calculated lengths I used the Law of Cosines (c^2=a^2+b^2-2abCOSc) to find the proper angles we needed. Drew these triangles out on the particleboard.


 * After class, I went to Derek's house and used his dad's table saw to cut the pieces we etched out on the particleboard. Have the proper pieces to make 2 legs and test them just need to finish building the frame for the crankshaft so we can connect them.

(November 29, 2012)


 * Went to Derek's house again today but to use his dad's table saw to cut the pieces for the frame. I extended the lengths for the frame and the crankshaft to allow more tolerance between the legs so it is not as cramped. Basically finished the frame and the crankshaft just need to add the end-caps to the pvc pipes and apply the glue to make a tight seal. Cannot do this however until we thread all of the legs pieces onto the frame.

My Fourth task

 * Finish cutting any pieces that still need to be cut, and simply assemble them together, creating the strandbeest.

Summary of actual work over fourth weekend
Finished cutting and fabricating the strandbeest.

Week4 Narrative
(December 3, 2012)


 * Today, was spent painfully cutting and drilling all the pieces. Since I had already drawn everything out it was a matter of simply cutting and drilling the holes into them. All work today was done at Derek's house. I cut and labeled the pieces of the legs using the table saw while Derek drilled holes in all of them to allow jointing. There was not really much variation in this work, it was simply just cutting the proper pieces out.

(December 4, 2012)


 * Today, I assembled the pieces we had been cutting for a week before. I glued and pieced everything together using a lift to hang the strandbeest from the ceiling.

The pictures of this build are below...

The final product can be seen in working order here, through this video.

Complete Team Page
http://en.wikiversity.org/wiki/StrandBeest/Howard_Community_College/fall2012/p3_501_DP#Week_Three_.26_Four