Tensegrity Playstations vs Xbox Structure

Summary Continuted: The logos are connected by two bolts of lightning. It stands as a symbol of the debate over which console is superior. You can also use it to hold items such as a water bottle. 

Link to Partners page: https://www.printables.com/social/396156-king-soham/models

Lesson Plan and Activity: With a partner, you will design and create a single custom Tensegrity Structure of equal complexity or greater as the tables depicted above (as determined and approved by the instructor).

Parts List: 

• 1x Xbox Logo
• 1x PS Logo
• 2x Lightning Bolt
• 2x Eye Hooks
• ~54 cm of 40 lb Fishing Line

Assembly Instructions:

Tools needed - hammer, pliers, nippers, small Phillips head screwdriver (to make holes), a ruler, pencil, 8 hooks, and 2 pair of strings. 

Hooks                                       Strings

1. Using nippers, make way for the hook to go in the lightning bolts.

1.  Hold the hook using small pliers, and hammer in the hook until it stands 

1. Then rotate in using pliers, or simply using your hand so that the hook is completely in the lightning bolt.

1. Fit the lightning bolt into the PS4 logo by wiggling it into the hole

1. If either lightning bolt does not fit, sand it down using sandpaper

1. Once the sizes matches, push the lightning bolt into the hole

1. Take a string about 23cm long, run it through one of the holes in the Xbox logo and tie a figure 8 knot at the top

• Instructions for the knots
  • Pass the tail over itself to form a loop. Continue under and around the standing end. Complete the knot by passing the tail down through the loop.

1. Tie another end of the string to the corresponding PS logo hole
2. Repeat steps 6 and 7 on the other two outer holes on the PS and Xbox logos

10) After the hooks are in, in both lightning bolts, take a string of about 6cm long, and run it through both hooks. Then, tie the two ends together using a square knot until there is 1-1.5 cm of vertical distance between the two knots. 

• Instructions for Square Knot
  • Hold the end of the rope in each hand.
  • Pass the right end over and under the rope in your left hand.
  • Pass the rope end now in your left hand over and under the one now in your right.
  • Tighten the knot by pulling both running ends at the same time.

A video for the square knot is followed. 

11) Once all 4 strings are tied, tighten all of them equally so that they are all in tension. The Xbox logo should be parallel to the PS logo, and all of the strings are vertical so that the holes line up. Your final model should look something like this. 

Design Choices: 

First, we modeled out a basic shape that we wanted to create our model based upon. We used shapes and lines in google draw to do this. 

Next, we began brainstorming a creative design for our tensegrity structure. We came up with a Playstation logo and an Xbox logo with a lightning bolt in between, signifying the debate on which console is better. We began drawing sketches of our ideas which are shown below. 

Then, we began going into detail on each specific part of our models. We drew and set coordinates for each point relative to the origin, and the designs are shown below. 

Once we had our designs done, we began creating our parts in Solidworks. Since we already had the anchor points plotted out, it was simple to create our designs. The initial Solidworks designs of our parts are shown below. 

After we had our parts created, we assembled them together in Solidworks. We realized that our Xbox logo wasn’t big enough so that the holes on the Playstation logo would line up with the hole on the Xbox logo. We scaled the part so that it would be bigger, and then we made sure that the holes would line up. Our instructor gave us an aesthetic tip that would both make our structure look better, and also save material when printing. He recommended that we hollow out the insides of the lightning. Once we did that, our assembly looked like this. 

We waited for our parts to print, and then we followed our assembly instructions to create our version 1.0 Tensegrity structure. 

We struggled to get the hooks lined up perfectly due to human error so we made a note to change that next time. Also, since we used hooks, we had to manually tie a knot to the hooks every time which proved to be very time-consuming, and also difficult to get all the strings tightened. Another problem we faced was that our model was too big. The Xbox logo not only used up too much filament, but it was also so heavy that it caused our structure to be lopsided.

Another problem we faced was that the hooks moved around a lot in the holes we made. To solve this we hot glued the hooks down in the first model, but we knew we wanted to make a change in version 2.0. 

Finally, we struggled to fit the lightning bolt into the Xbox logo, and we were forced to sand it down. For version 2.0, we made a list of the changes we wanted to make. 

For starters, we added a 10mm chamfer around the peg of the Xbox logo. This would make the fit of the lightning bolt into the peg much smoother, and minimize the amount of sanding we would have to do on the bolts to make them fit. 

Before After

Next, we scaled the model down 0.75x which helped save a lot of filament. Additionally, we removed some filament from the top of the Xbox logo which not only saved filament, but added to the aesthetic of the design and helped prevent the model from becoming lopsided. 

Finally, we made a significant change by creating holes in the logos instead of punching the holes after the parts were printed. This would mean that rather than using hooks, we could just run the line all the way through the holes. This would help combat the problem of the hooks moving around in the holes because we would not be using hooks any more. Also, we would be able to tighten the strings much better because we wouldn’t be tying knots to hooks, but we would just have to tie a stopper knot at the top of the logos. 

After we made these changes, we printed the parts out and followed a modified assembly instructions. 

Overall, version 2.0 was much more successful than version 1.0. Our structure was not lopsided, and the strings were much tighter because we used holes instead of hooks. This also led to our structure being much stronger which made it better.