Full Sculpture

Challenge

Objectives

During the fourth and last week of the COSMOS Cluster 2 on Engineering Design and Control of Kinetic Sculptures, our team has to integrate the Mini Sculpture concept(s) into a working Full Kinetic Sculpture with no size limit. Lessons learned during the prototyping of the Mini Sculpture are now applied to ensure the Full Sculpture operates autonomously and is robust to any design or programming errors found during the Mini Sculpture design.

Design Requirements

The marbles must be contained within the sculpture i.e. they can not hit the ground.
The sculpture must be cyclic, so that it would run infinitely
It must have a user input with both an output through the motion of a motor and through text displayed on the Lego Brick
The full sculpture must include the mini sculpture
At least one sensor and one motor must be included
A motor must change dependent on a sensor
Limit use of duct tape, cardboard, or other temporary materials to achieve a more professional design

Brainstorming

H-Belt

This was an idea we were considering. It would be able to move the funnel in two axes. Ultimately, we decided it would take too much time to implement.

Error Reduction: V1

In order to contain the marbles within the structure, we surrounded our basket and collection track with vertical tracks. While this reduced error, it blocks the moving basket which is the most interesting part of our sculpture. Therefore, we removed the upper level of tracks to keep it visible.

Error Reduction: V2

Even after removing the top layer of the vertical tracts we still disliked the look of the design. Therefore, we decided to use cloth instead, as it looked better than the tracks. We wrapped the entirety of the bottom part with the cloth and left open a small portion to allow the audience to view the cart. However, we realized that this design allowed for the marbles to get stuck in between the cloth and the track.

Error Reduction: V3

Our third iteration was using blue structural pipes. This solution wasn't perfect and marbles did still occasionally escape, but it worked better than the cloth and looked more professional than the vertical tracks.

Troubleshooting

Auto-Catch: V1

Although our mini sculpture automatic ball catch worked smoothly, once we modified the structure it became inconsistent. Our initial solution to this was adding bells in the stretch of track before the ball falls from it, slowing the balls down. The original speed of the marbles were too fast and did not give sufficient time for the basket to move to the calculated position.

Auto-Catch: V2

Even with the bells, the automatic catch system would still miss a large amount of the time. We thought that the delay in communicating the speed to the NXT Brick, making calculations, then sending an command to the basket motor was too great and causing the basket motor to have a delayed reaction. Therefore we moved the speed sensor farther from the edge of the track, allowing more time between sensing the speed and the basket having to move.

Auto-Catch: V3

Upon further inspection of the basket carrier itself, we discovered that the error-reduction devices we implemented were protruding onto the basket's path and causing resistance. We quickly adjusted them and fixed the problem.

Gate Motor Mount

We made a gate from Lego pieces and a servo motor. This was mounted on with only one connection point originally and was liable to fall off. Our solution was to add another clear bracket to secure it better.

Final Results

More Tracks and Features

Since we were making a full sculpture, we wanted to expand the structure and include more tracks and features. The new features included a bell, a gate, a pendulum, a funnel, and a spiral, and a trapdoor.

Bell

When the marble goes through the track, it pushes the spring outward. This translates the marble's kinetic energy into the spring's elastic potential energy. Once the ball passes, the energy gets converted back to kinetic energy in the spring. The spring snaps back and hits the bell, producing a clear note. The bells also function as speed reducers because of this energy loss.

Gate

The gate is a lego piece attached to a rotation motor, randomly interfering with incoming marbles. It creates more variation in the marble's velocity and landing position. This mechanism was added to make the user control more challenging and interesting.

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Funnel

The funnel allows us to provide a clean transition from the collection track of the catch game to the rest of our sculpture. It is also adds more to the visual appeal, as opposed to simply putting more tracks in its place.

Pendulum

The pendulum allows the ball to go on two different tracks. When the ball falls from the above track, it randomly goes to one side of the pendulum or another. The weight of the marble then tilts the pendulum to that side and gravity causes the marble to roll off. This adds more variability to our structure.

Spiral

The spiral adds visual appeal and more interest to our sculpture.

Trapdoor

The trapdoor feature allows us to easily switch the marble's direction. When the marble rolls over the trapdoor, the trapdoor pivots from the weight and deposits the marble on the track below it. Additionally, when the trapdoor resets itself, the xylophone part attached to a spring hits a metal backing and creates a xylophone sound.

video.mp4

Combining Everything

Below is a labelled picture and a video of our entire sculpture.

video.mp4

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