User:Cwoo4792/enes100/Robot Arm

Link to team page. TFCW

Give instructor top 3 project choice list
1.Robot Arm 2.Robot End effecter 3.Rube Goldberg

Write problem statement
Create a functioning robot arm that is light enough to move and be controlled by motors or servos and has a working end effector that is able to pick up objects.

Assign Task1
Research functions of a robot arm. By using online resources and looking through past projects.

Compare actual work done to Task1
My goal was to research functions of a robot arm by using online resources and looking through past projects. I was able to find out that the previous project based their design off of the festo robot arm design using the flexible rods. I was able to understand how the arm worked by viewing the videos and I was able to make a miniature prototype arm using plastic wire and lego mindstorm pieces.

Week1 Narrative
In the first week of project robot arm my goal was to be able to understand how to build a working robot arm. I was able to find out that the previous team build a robot arm based off of the Festo design called the Bionic tripod 2.0 seen in the middle of this | Video. The previous team however did not use as many rods and the rods themselves were too stiff and connected at too many points to provide almost no movement.I was able to figure out by viewing the video that the arm works by pulling and/or pushing the rods to make the arm turn in a desired direction. I then began building a miniature model of a three wired arm by using plastic wire and Lego mindstorm pieces. I connected the ends of the wire using a Lego tire rim piece a gluing them into the holes. I connected the center of the wire using a 6 holed piece and hot glue. I then made a miniature base and frame that I was able to slide the ends of the wire through and be able to push and pull the wire. I discovered that closest point at which the rods are glued is the main point at which the arm will bend. The rod connectors may need to be loosely connected to the rods rather than glued to provide more flexibility. This may be an other reason why the previous project arm was so stiff. More testing with the miniature arm needs to be done before attempting to build a larger scale one. Also, some pull and push system needs to be developed that can also keep the wires from rotating out of place. Miniature arm

Week1 Peer Review
Week one peer review

Assign Task2
Refine miniature robot arm to make it for flexible and sturdy. Possibly add an miniature end effector and string.

Week2 Peer Review
Week two peer review 

Assign Task3
Add miniature end effector.

Compare actual work done to Task3
My goal was to refine the miniature robot arm to make it more flexible and sturdy and possibly add a miniature end effector and string. I was able to add more free flowing connectors that made it more sturdy and allowed for more flexibility when moved I was also able to make container that held it vertically rather than horizontally out of a cardboard box so that I could place things in the box to test the effectiveness of the arm or of an end effector. I was able to create an end effector that had the ability to close when the connected string to the end of the post inside of the effector was pulled. It would aromatically open when released. I was able to pick up a Lego piece that was placed anywhere in the box because of the flexibility and control ability of the arm. However, it was hard controlling the 3 wire ends and string with only two hands so something needs to be built to make controlling the arm easier.

Week3 Narrative
During this section of the project I set out to make the robot arm more flexible an sturdy. The problem was that the arm would bend only at the point were it was glued and the rest of the arm would be flimsy and not well held together. I was able improve it by adding three more connectors that would connect the wires wider the higher you went up. This would allow the connectors to naturally stay in place yet allow the wire to be passed through it to allow for more flexibility. After that an Idea was sparked in me to have the arm hanging vertically from some sort of box rather than horizontally from a stand. I was then able to find a cardboard box and connect the end of the arm thought the cardboard box so that I could control the arm from the top. I now need to find a way to mechanically control the arm by pulling the different wires of the arm upward to cause the desired turn. Here are some pictures of the progress with the Robot arm: During this section of the project I was also hoping to be able to create a working end effector for the Robot arm. I started off by drawing possible designs for a miniature end effector because I was unsure that the original end effector, built by the previous team, would be too big to duplicate on my miniature arm. I then started looking through Lego pieces to find possible fingers for the designs I drew, but I was unable to find any that would be flexible engough to pick something up. I then came up with an idea of duplicating the previous end effector but with smaller fingers, and less cross pieces in the fingers. Also instead of attaching strings to each finger I attached all the fingers to a central circular Lego piece that would be pulled by a plastic wire. What I came up with is seen. I then tried picking things up with it thinking the cross pieces weren't needed but it was very weak and did not curl around the object so I soon added. I then attached the end effector to the arm using tape as a temporary solution and I was able to pick up a Lego object with the arm. Here are three pictures of the arm picking up the piece:, ,. I will now seek better ways of controlling the arm from the box.
 * http://commons.wikimedia.org/wiki/File:Top_of_box_with_connectors.jpg
 * http://commons.wikimedia.org/wiki/File:Top_of_the_robot_arm.jpg
 * http://commons.wikimedia.org/wiki/File:Ends_of_the_robot_arm_fed_through_the_box..jpg
 * http://commons.wikimedia.org/wiki/File:Robot_arm_in_box.jpg

Week3 Peer Review
Week three peer review

Assign Task4
Work on a pull/push mechanism for each arm possibly by manually having a manual holding and adjusting system or a motorized system.

Compare actual work done to Task4
My goal was to work on a pull/push mechanism for each wire of the arm by possibly having a manual holding and adjusting system or a motorized system. I was able to built two holding and adjusting poles out of Lego beams that allowed me to hole each side in a turn while manually curling the arm forward or backward with the front wire. I was unable to get a system that could lower or raise the arm after the arm was adjusted to the desired position but I will seek solutions in the next project section.

Week4 Narrative
During week four of project robot arm I set out to try to build a mechanized or manual system that would raise and lower the individual wires or the robot arm holding them in place. I began seeking multiple push and pull systems as well as railing systems and sliding systems. However, I was unable to implement any of theses systems due to lack of materials, time, and ways to control hold each of the sliders in place. I also tied connecting all the wires together like a puppet, but tuning and curling relied on turning and curling the piece holding the wires together which resulted in lack of flexibility and smoothness of control. Finally, I decided to add two Lego beams directly behind the two lateral wires. By adding peg like Lego pieces to the ends of the wires I was able place the wires at different levels while having them held in place by the. With this holding system it made it easier to control the direction of the arm while manually pushing or pulling the front wire. Essentially it gave me two extra hands to hold the side wires in place while I controlled the front wire and end effector with mine. I was unable to get any mechanized raising or lowering system but I plan on continuing the project to build such a system. Here are more pictures of the arm and a | video shot by Timothy Francis:

Week4 Peer Review
Week four peer review

Complete Project Page
Follow the "project done" format.

Start Next Project Week0 activities
Work on raising and lowering system of Robot Arm.