Group 04 meeting 5

           

Discussion on Rubber Bands vs. Springs

        The following meeting group come up with a problem that rubber bands don't follow hookes law which means that the force that produce is not directly proportional to the stretch it displacement put on them. So group come up with an idea to replace the rubber bands to springs. The springs do follow hooks law and, therefore, are more predictable. Also, rubber bands produce more force when they are charged and discharged instantaneously, whereas springs can hold their energy for longer without it dissipating.
          However, the group decided to use springs instead of rubber bands and the other part of the body will use lego parts and an xl motor. As a result of all this change the group budget has reduced to 30 dollars. Also, the group has to draw a figure that more likely looks like a future project.

In conclusion, over the weekend group planning to visit a lego store and but all the parts that are required for the project and work on designing. The next step it to decide how much power our prototype needs, but it hard to say until we don't  have a model done. 

Group 04 meeting 4

     



        The group has met fifth time on the lab section. On the day group was divided by two groups which include three members. The Group 04 whose is now of three people keep posting this blog.The groups have a chance to stick with the same project, but to do it separately.         
       During the lab, the group have looked over the design and decided that it can base off of a grasshopper. However, the group initially wanted to mimic  all of its muscles, but the Dr. Abdel-Aal said the we were making it to specific because after all we need to think about how we can apply our design to the real world. Also,  the doctor has mentioned that there is a difference between mimicking a thing exactly and mimicking its function. We change our approach from exact mimicry to functional mimicry to allow us to design and build the project more easily.  
        Next meeting planning to be on October 22.
   
       

       

Group 04 meeting 3

       

Choosing the project

           Group have met with the coordinator to ask some advice about two ideas that they have come up with because the both ideas were very interesting. As was mention before the first idea was Grasshopper, which showed on Figure1.  The second idea was the jumping machine in a kangaroo's leg, which shown on Figure 2.

Figure 1

                                                                       
                                                                             Figure 2

       Finally, the idea that has chosen is a grasshopper machine. The main goal of the machine is to create an energy storage device with the intention of using it to build a machine with the ability to jump. The design is based on the leg muscle of the grasshopper. The grasshopper's jumping abilities are interesting they rely on a mechanical disadvantage in the typical sense. The muscle of the grasshopper has to provide a (relatively) very large thrust in order to supply enough force to create lift after that force has been diminished in magnitude by the lever in its leg. To do this, the muscle is not aligned directly with the axis of movement. Instead, the fibers come off of the axis at an angle, and all work together to create a much shorter but far more powerful movement.
     In addition, the group has talked about the budget. We all have decided to put $25.00 each towards the project wich leaves us with $150.00 to spend on mechanical hardware and servo motor and component. 

       Overall, on the next meeting group planning to discuss building energy storage device and building prototype.

      

Group 04 Meeting 2

Group 04 Meeting 2 - Thursday, October 8, 12:00 pm

      The group met in room 226 of the Library to discuss our findings. Three separate proposals were submitted. 

      The first idea was to use an electromagnetic field to propel a projectile out of a solenoid, producing upward lift. The group decided that it was in our best interest to attempt to mimic biology more closely.

      The second was to mimic the jumping mechanism in a kangaroo's leg, using an arm attached to a periodic motion device to move a spring powered assembly around a track. The track had a curved section that allowed the spring arm to be compressed and a straight vertical section where the spring was free to decompress and thereby produce lift.

       The third proposal was to mimic the muscle in the leg of a grasshopper. The muscle produces a strong force over a short distance, which is applied to the short side of a lever. The lever acts on a fulcrum to reduce the overall force but increase the distance that the force acts over, thereby producing lift. A member of the group suggested a periodic motion device with a short channel along the path of the motion, which would allow the device to charge the spring in the arm while still allowing it to discharge.

        Overall, the group decided to further investigate the second two design options and meet with the teaching fellow to discuss the pros and cons of each. The next meeting time is to be determined by email when the fellows office hours become known. The group will hold it's next weekly meeting regardless on Thursday, October 15 at 12:00 pm.

Group 04 Meeting 1

Group 04 Meeting 1 - Monday, October 5, 2:00 pm

     A group of 6 was formed and early discussion of design proposals began. Biomimicry was suggested as a tool to help with the design process. The group agreed to create a spider based hopping machine. The group decided to research different animals and insects individually and to meet back on Thursday, October 8 at 12:00 pm to discuss our findings.