Sebastiaan FabAcademy

Week 9 Make a machine

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This week we had to a group assigment. The team members at The Waag are: Eva Korae Sander van Vliet, Paul Groneveld, Jacopo di Matteo, Marije Kanis and Shunichi Mizugaki. The only day we all are at The Waag is on Wednesday. So that make the team effort a bit difficult. We had to devide our task and any one has his own skills.

Link to the Groep webpage

My contribution to this weeks assignment will be explaned in the following. We startet at The Waag on the thursday. Together with Paul we had already been surging for interesting machines and principles. Being triggered by Paul about the Festo Innovation and technology I discovered the Festo Bionic Tripod. When I saw this, I was immediately a fan of this robot system. I also know that I had a fiberglass wire of 3mm stored for almost 20 years in my barn, that would fit perfectly.



In had other plans for this fiberglass wire but I took it from home to the Waag so we could start working with it.



Thursday morning we startet brainstorming with Eva, Paul, Emma, Sander, Mickael en me. Each of us had to write down in 5 minutes idea's for the machine. Then came the funny disussion between the team members. More Idea's crossed the table



On this picture on the top of it my idea's. I had in mind to do something with the city of Amsterdam. nearby the Waag is a marionette theater But the innercity of Amsterdam has it typical sound where a soundmaking machine can reproduce this "sound of Amsterdam"



Then came the funny disussion between the team members. More idea's crossed the table but it was time to make choices and we devided the idea in circular motion, writing text, making drawing, stamping something, using water in the process/use floating elements. We discussed again and decided that the machine should make us laugh, anyone can use it, having an organic motion/flexible part, including an interface. Then we had to think about functions and came to the list below:



After voting we decided we would be making a Random answer machine!

The result of the whole project is documented on this page.
Here you can open a poster presentation of the project Poster
Here you can find the information about the coding of the drie axis: coding
The video of the end result is presented here:

To make the machine and use the Stages that we had to use, we decided to use the concept of the Festo Bionic Tripod By translating the fiberglass wires the robotic arm can be positioned by changing the stages. Like a marionette by pulling and pushing the fiberglass wire up and down, we decided to make a vertical machine, the arm can be bent sideways and pushed upwards. Paul and I sketched a lot on the whiteboard and analysed how the Festo machine is designed and how we could make it in a more easy way. We had to be practical, since we did not have a lot of time. The goal was for this thursday to have to concept ready.



The next goal was to understand and analyse the basics of the Festo Tripod machine. I draw in SolidWorks a cardboard diverder. Shunichi cutted it on the laser and together with Sander we assembled the first arm together. We had to decide what the distances would be between the fiberglass wires and so our first test model was equiped with several extra holes to guide the fiberglass and aluminium tubes. First we tested it with a small distance between the fiberglass

Sander and I cutted the cardboard deviders for fixating them togeher with a spring



We assembled the aluminium tubes in the other cardboards and guided the fiberglass in them



First try to pull a fiberglass wire and the arm started to bend, but is was very unstable. So I looked to that how we could solve that.



But we were able to bend the arm. But what happend, the arm was also twisting. The fiberglass wires were bending in a position for less tension. So we had to find a solution to fixated the fiberglass wires better so to keep there position against each other.



The second test was to increase the distance between the fiberglass wires.



This configuration was much more stable the the smaller one.



We were able to control the movement much better



See the black tape underneeth the cardboards. I already dicovered that the cardboard should have a fixed position to keep the fiberglass wires in a stable positioning. Otherwise the pushing wire goes it own way and bends only instead of pushing the arm.



On the next wednesday Paul and I were back at the Waag and started early in the morning. In the beginning of the week the rest of the team had laser cutted the wooden frame structure to hold the stages. So we could use that to analyse how big the bow had to be, to fit the cards in. We already had made a stiffer connection between the glassfibers. I had analysed the Festo Tripod machine well and discovered that we needed a stiff end-bracket and a stiff connected diverder, but with some flex in it. Below you see that the distance between the fiberglass wires is held together with metal baljoints but fixated on the fiberglass wires so they can not twist.



Here an other detail view of the middle diverder of the fiberglass wires.



Detail view of the stiff connection on the top



And guideness of the wires below



We designed a flexible wooden part that should fix stiff to the fiberglass wires. Paul was a bit faster in drawing the middle diverder in SolidWorks and so his part was then cutted on the laser. I had the same in mind but designed it differently. The first cutted part hadn't enough flex in it and broke and the improved version had more flex and enough stiffness. I took from home a small innertube of my racing bicycle and we fitted the rubber over the wedge and so we could generate enough friction to prevent that the fiberglass wire will come loose.



Next was to define the size of the bow, with contains the cards. Paul and I worked together. I pushed the fiberglass wires up and Paul marked the outer position of the vinger with post-its on the wall.



We took a picture of the post-it cards and imported it in SolidWorks. We measured the height and width and changed the size of the picture to these dimensions



In the next two slides the post-its where connected with a curve in SolidWorks





The curves where optimised



The dashed yellow line is added as an offset to the outher line. This is the movement of the hand to push the cards up. I discovered that the maximum bending was not the maximum postioning to push the cards upwards. The smallest bending radius (white) is crossing the yellow dashed line. So this is the maximum positioning of the arm to be able to push the cards 10 cm upwards.



Also in the background picture the arm is positioned in the maximum bending position.



In the next slides the wooden bow was drawn in SolidWorks.



Because one bow was to big to cut and will use to much material I suggested to cut the bow in sections.



I discovered that the first test with bending wood cards was to fragile. The size also to large and took to much force for the flexible arm to bend them upwards, I took plastic sheets from home to be cutted in smaller cards dimensions of 200 x 154 mm. We did some test do bend them upwards and this looked fine.



Paul and I designed the cardholders and made them fit in the bows, by clamping them in the bows.



Next thing was to construct the bottom plate to hold the bows and the stage-construction.



Detailed view of the complete construction.



We did not made the assy complete, due to time reasons. The missing parts are the same as the one that are displayed







Next thing what I did was making pictures of the other members how we all where working on the assembly and lasercutting of the parts and try to manage the stages.













I helped them assemble this stages construction







We needed a stiffer top bracket to hold the glasfiber wires. So I drawn in SolidWorks a new one.





I helped assemble the fiberglass wires to the stages



I cutted the cards to the right dimensions



I collected these pictures and have send them to the other team members with additional text, so the could use them for the group webpage and there own websites.

I also made the first movies of the moving arm.

movie 1 : first test with the stiffer connections

movie 2 : Moving the first stage

movie 3 : Moving one stage with the fiberglass wires connected

movie 4 : Moving one stage with the fiberglass wires connected

movie 5 : Moving for the first time the cards with all the stages operating

movie 6 : Bending the arm in 360 degrees

I also had to help from a distance how the team members should assemble the machine. Therefor I had to made additional hand sketches to help them to understand the construction of the machine



The other team members had troubles understanding how the cards should be build in to the machine. The sketches helped them.



Because the members working in Amsterdam did get in time problems, I offered help in making more cards. I made a cutting file ready in Illustrator



Then with the vinyl cutter I cut all the text for the cards



I designed in Illustrator for every text file a square, with the same dimension, around the text, so I could use that to aline the text on the foil.



After sticking the transferfoil on the sticker, I could remove the backing. We had decided to stick the text on the backside of the card, to prevent that the moving finger will tear the sticker of the foil



I had to cut the foils to the right card dimension



Next I positioned the sticker between the tape that marked the right position on the foil. Then I positioned the foil in the corner en gently pushed the foil over the sticker and pressed the sticker well. Now I could remove the rest of the sticker



In this way I was able to stick al the 16 stickers within 1 hour. I didn't had more time left so this was perfect.



Next I assembled the cards to the bow of the machine



This was the work it did for the machine building.