Phase 1: Prototyping Motion

Prototyping Motions.

Welcome to my process pages, these sections will act as a working diary/blog to document my prototyping of each sculpture and my discoveries through trial and error. A more polished page for each finished sculpture with opensource files and instructions is to come.

I have broken down my project into phases which I have outlined on my deliverables page. These sections are structured in the same way.

Phase 1 of my project is to PROTOTYPE MOTION (13th January- 2nd of February). My focus for this phase is:

• DESIGN
• TESTING
• PROTOTYPING

My goals for this phase are to:

• Create an inital design for each sculpture and decide on what kind of movement they will have.
• Test different mechanisms and hardware to create this movement.
• Have a working Prototype for all 3 sculptures.

SCULPTURE 1: DAPHNE.

The first sculpture I am prototyping is Daphne based on the blooming movement and rhythmns of flower.

Here is my initial inspiration for the form and movment I wanted to create and my sketches. I wanted the movement to be at least 4-6 parts opening and closing like a claw. I wanted the movement to be smooth and curve inwards as it closed.

I began by looking at lots of examples of mechanical flowers and tried to analyse or find open source information about their mechanisms.

I identified 3 possible mechanisms which I explored and drew out:

GEAR AND RACK.

This mechanism is based on the movement of a gear across a rack. However, in this case the rack moves back and forth rather than the gear and the gear is held in a fixed position above it. This allow the gear and its extension to move in a 90 degree arc rather than a linear back and forth.

To explore this mechanism I used this instructable: Solana the Sunflower using the .dwg files they include in their documentation I just got started.

I feel that I understand things best from doing and having something in my hands that I can help to visualise was very helpful.

HERE IS IT IN ACTION:

I found this mechanism unreliable and reliant on a materials such as fishing line and elastic bands to create the motion which were not very resiliant and temperamental. The motion was either very loose or staggered and requiring a lot of force and it didn't give me hope that I could achieve seamless movement with this approach.

PUSHER AND GEARS IN THE ROUND

As I learnt in Open source hardware week, I killed my darling and moved on to exploring another mechanism I found on... you guessed it ✦ Instructables ✦. I had seen multiple examples of a mechanism like this used and thought it looked reliable and smooth.

I had been to see William Darrell's exhibition "On the Shores of Obliion" at Somer Gallery recently and was amazed by the graceful movement gears offered and how they could translate on motor movement into many when used in tandem.

I ended up finding this amazing tutorial Kinetic Origami Interactive Art which again has Rhino files for the mechanisms and downloadable stls.

The mechanism is essentially a linear servo actuator that moves a plunger with gear teeth up and down. When this moves up and down it turns the gears fixed around it by hinges (much like the first mechanism) so that they move in a 90 degree arc.

I drew out my understanding and how I would adapt it to my project:

Then I began to 3D print the pieces on the Creality Ender 3 (Ø1.75mm, Bowden) with 1.75 mm PLA white filament.

Unfortunately, I had some issues with the servo linear actuator and the ratio between the servo gear and pusher plunger. I had to do some trial and error in Prusa Slicer with the scale factor to make pieces fit together.

I settled on scaling the plunger rack by 90% on the z and y axis but 80% on the X axis. I similarly had to change the dimensions of the servo gear in rhino to fit my servo motor (Tower Pro Micro Servo 9g SG90). I also scaled this by 90% in Rhino, added a top covered the top of the gear and added a 2mm hole for the servo screw.

The .stl file for the adapted servo gear is downloadable on sketchfab:

Servogearadapted by issy2842 on Sketchfab

Once I had everything the right size and printed I put it together in a quick and dirty prototype and was really happy with the result!:

I immediately felt like this was the right mechanism for Daphne. The movement was very smooth and predictable and could easily be modified by the length of the rack and the code I use to control the servo with the proximity sensor.

My problems with it are:

• that I would probably need to use a higher torque servo motor and therefore I would need to frankenstein into the file a different linear actuator (this one from thingiverse.

• I really loved the 6 "arms" on the first model rather than 4, I think the blooming would be nicer and they would come together to make a more curved shape when the flower is closed.

To remedy this Asli helped me to modify the design in rhino and use Array Polar to make the mechanism work with 6 gears. We also used the scaled up version of the components as I would eventually also like the gear system to be as big as the first Solana prototype.

Here is the .stl file for the new model:

6 gear holder and pusher gear by issy2842 on Sketchfab

I am really happy with the way the next version is printing! The ratios of gears are still correct and working and the scale is much more appropriate!

PUSH ROD

I am now very settled on the pusher mechanism so I didn't feel the need to test out the push rod mechanism that I also researched. However, the construction seems very simple and is almost like a reverse umbrella. It was an interesting exercise to understand given that it is essentially the same as the pusher mechanism but without the gears.

SCULPTURE 2: PHILOMEL

My second sculpture is Philomel which is inspired by the rhythms of bird migration.

Here is my initial inspiration moodboard for the sculpture and a little video I took on a walk where the birds had the exact energy I want to create with my sculpture.

I started drawing out my ideas for the form the sculpture will take. I think the form depends a lot on the mechanism I create but I know I want to have multiple wings that are suspended in such a way that the individual birds are abstracted and appear to merge when they move like in a flock.

For the mechanism I was looking into open source projects and tutorials on building a motor powered ornithopter with articulated wings.

These were the sources that inspired me and that had the motion closest to how I was visualising it in my head.

Again I started by drawing out the mechanism to think through a first prototype based on what I had seen in the videos.

I had seen Michelle Vossen's documentation for her Machine Design week during Fabacademy and I thought she took a nice approach to working out the dimensions of the ornithopter pieces by laser cutting pieces of wood with lots of holes in so that you can try out different combinations of lengths.

I quickly got to work making a file based on rough estimates and laser cutting the pieces from 6mm ply.

Next, for my gears I generated some basic gears using STL gears.com. I again estimated what I might need ensuring that the diameter of the gear was wide to maximise my movement.

In Rhino I added various holes from which I could connect my wings so that I could try different distances from the Bore.

I also made some spacers of different sizes so I could test these as well.

Here is the stl file for my gear:

ornithopter prototype gear by issy2842 on Sketchfab

The assembly process was very quick and dirty and I realised when I got home that the holes I had cut for my gears were misaligned so it was very tricky to actually make the gears turn. This is something I am going to have to fix in prototype 2.0.

Overall I am really happy with the way the ornithopter moves and the shape it makes with the wings. However, it is still a very unreliable and faulty mechanism. The bolts and nuts I used for hinges constantly came loose disabling the movement and my gears were very misaligned. With this prototype it was difficult to get the two wings moving at the same time and I had to constantly adjust things so it would keep working.

Going into prototype 2 I will:

• Using mini bearings instead of screws at linkage points and on gear bore.
• Working out precisely the distance between the gears.
• Using book screws, push rivets or locking nuts to keep any screws in place.
• Intergrating a stepper motor.
• Upgrading material and shape of parts.

SCULPTURE 3: AMPHITRITE

Finally, sculpture 3 is Amphitrite, whose movement is based on the blossoming ecosystem created by whalefall in the deep sea. The patterns of decay and growth being the start point for the forms and rhythmn.

My initial sketches for this sculpture incorperate the idea of a disintegrating skeletal form which moves in a wave like motion. I want ambiguity over whether the sculpture is inanimate or animate. Through the use of textiles and laser cutting I will then attach intricate shapes and patterns that will sway and billow with the movement of the piece (if I have time curling in and out also like in my wearables assignment)

The mechanism I am prototyping for this sculpture is a Sine Wave Machine which simulates the amiiform locomotion of fish. A very simple mechanism using a rotating axel and circular discs rotated at different degrees around it. Translating a circular motion into a sine wave.

I am still working out this mechanism for prototyping this week but this is my research so far:

and initial sketches: