Project By: Rahul Ramnath, Nathan Hartley, Myles McVey, Antonio Noya

Customer: Dr Annet Couwenburg

Advisor: Dr. Tim Topeleski, Dr. Jamie Gurganus

Summary

Customer

Dr. Annet Couwenburg is a fiber artist that creates pieces that represent the interface between the individual and rest of the world. The Cleft piece that is the center of our project, is a fiber piece made of plastic and felt. The piece originally sat on the ground, but the artist wants the piece to be interactive between the viewer and the piece. The piece resembles the structure of a jelly fish like creature and a 17th century Dutch collar.

Background

Dr. Couwenburg wants the Cleft piece to be interactive with the viewers. In order to make the sculpture interactive a structural frame and control system must be created. The control system will take inputs from the viewers and translate that into motion in the sculpture. The structural system will support the sculpture in the air and serve as a base to put all of the control items required to move the piece in accordance with the artist’s needs. Another aspect of our project is to design the system to be able to be taken apart and reassembled easily in other gallery locations. In order to do this the system has to be modular so the parts can be found easily and do not have to be fabricated if anything happens to any of the pieces. The components of the system also must be robust so they can handle the wear of being moved around and shipped frequently. The system we are designing, will require three inputs: parameters of the exhibit space, the art patron's movement, and power. The output of the system will be the stress on the ceiling and the heat and noises added to environment. Parameters of the exhibit room include dimensions of the room as well as other objects in the exhibit. The art patrons will be the largest input for the system, as their actions will dictate the movement of the sculpture. A power supply will be needed, as the system will have devices that require electrical power.

System Requirements

Some key requirements of our system include the suspension cable system being able to withstand a 200lb static load. Additionally, each suspension cable should be able to withstand a dynamic load of 200lbs, and be able to move a minimum of 18 inches vertically, in order to produce sufficient motion of the sculpture. The structure itself should not deflect more than 6mm at any location, and should also weigh no more than 30lbs, to keep the system lightweight and easy to manage.

Design Process

Bill of Materials

Total cost:$301.07

Cost excluding items not purchased: 187.11

The budget for our project was $200. Our proof-of-concept full scale design cost a total of $187.11. A full break down of the price can be seen in Appendix B. If we did not have some of the materials before starting the project, like the stepper motor, then the total cost of our full-scale proof of concept would have cost $301.07. For the final design there is additional funding being provided by the artist by the gallery space to create the final design with the full aluminum frame, stepper motors for every section, and one sensor per one section. The total cost of the full design would cost $2126.16.

Verification and Validation

Functional Requirements

To meet the functional requirements of the projects tests were performed on the controls system. The ultrasonic sensor was validated through requirements 1.2, and 1.3. These requirements were tested by having the tester move forward and back from the sensor, the sensor records the value, and the value is validated with a tape measure. Requirement 1.3 was tested by connecting the Arduino, ultrasonic and stepper motors. Once connected the tester would move back and forth, the distance would be processed, and the motors would move the specified number of steps. As the tester got closer to the sensor, the motor would raise the sculpture up higher. This movement confirmed that that the Arduino was properly sending information to the stepper motor.

Performance Requirements

To meet the performance requirements physical tests of our prototypes were conducted. Due to various factors requirements 2.1, 2.2, and 2.3 were not able to be tested. The main reason is that our final system has not be built yet. Requirement 2.4 has been tested by running a Finite Element Analysis (FEA) on the CAD model of our final structural frame. Overloading the frame in a worst-case scenario in our FEA has proven that it will meet the requirement. The last performance requirement, requirement 2.5 was also tested. Our final prototype / proof of concept demonstrated that the dynamic line would be able to achieve more than 18 inches of vertical movement thus meeting the requirement.

Regulatory Requirements

Many of the regulatory requirements discussed in the system requirements specifications could were not met. Requirements 3.1 and 3.1.1 can no longer be met, as the customer has moved away from the use of fiber cables to steel cable. Requirements 3.2 and 3.2.1 could not be met as the final frame design is yet to be constructed. Finally, requirement 3.3 was met by purchasing CSA No. 49 standard for wires. The full list of requirements can be seen in appendix A.

Conclusion

Our project was a proof of concept for a much larger project for the same client. Our end point for the semester was one working module of the final moving art sculpture for Dr. Annet Couwenburg. There is more work to be done on the project that the team will perform in our spare time throughout the next semester and over the winter break.

The main problems we had when testing our design was the ultra-sonic sensor that was being used to measure the distance and thus the number of steps to move the sculpture was malfunctioning and reading only values between 100 and 120 centimeters. With the final full design more robust sensors will be needed, either in the form of more durable ultra-sonic sensors or infrared laser sensors will be needed. The system still responded like intended. When the sensor read a larger value, the sculpture moved less and when the sensor reads a shorter distance then the sculpture moves less. This means that code was working as intended. For the final design there are going to be 15 motors and 15 sensors. In order to reduce the number of Arduinos required for the project timers will need to be utilized in the Arduino to control multiple motors at once on the same Arduino.

During testing we found that the motor was making a lot of noise and causing vibration in the wood support structure. This means that there are some inefficiencies to be addressed in our design. The motor noise is going to be present, but there are ways we can damped the noise using foam or cloth in our frame that can absorb the sound waves and shorten the travel of the sound waves. Another problem that was found during testing was vibration in the beam that the motor was mounted on. A way to reduce this vibration is to use rubber spacers or non-metallics mounting equipment or fasteners to damp the vibration from the motor. Damping the vibration will be more important when the motors are mounted on the metal frame as the vibration will cause a higher frequency noise in the metal than the wood used for the test frame.

Future Work

The next steps that need to be taken to complete the project are creating the full-scale dual hexagon frame that sculpture will be hung from. In order to do this the aluminum channel and plates must be ordered. The plates will be custom fabricated to match the required angles of the frame structure. The control system needs more programming to make use of the number of pins on each Arduino controller. In order to do this, the pin must be programmed as the inputs from the many distance sensors and to send control signals to the stepper motors for each corresponding sensor. The Arduino code will also have to modified using non-blocking statements so more than one set of sensors and motors can run at the same time. The full set of 15 motors will need a larger power supply to provide enough energy for each stepper motor to raise and lower the sculpture. In order to this more power supplies will be needs. It will be best to separate the whole control and electrical system into a few different modules that make use of the provided electricity and ports on the Arduino efficiently to cut back on the cost of microcontrollers, power supplies, and wiring. A modular design for the control system will make it easier to track down problems to certain components because it will be easier to isolate where the problems are occurring.