Vibration Isolation System

1. Vibration Isolation System Project by: Monroe McCarty, Alex Mills, and Zachary Kamm ET – 493 Senior Design I Fall 2018 Instructor: Dr. CrisKoutsougeras Advisor: Dr. Ho-Hoon Lee

2. Introduction • Vibration is undesirable in many systems and habitable spaces, and thus various methods have been developed to prevent the transfer of vibration to such systems. • Vibration isolation is the process of isolating vibrations from an object such as a machine or a piece of equipment.

3. Objective • The objective of this project is to design and build a prototype one-degree-of-freedom vibration isolation system to perform various vibration experiments • In this system, the vibration of various excitation frequencies will be generated by an unbalanced mass whose rotating speed will be controlled by using a DC motorconnected to an Arduino Uno Board

4. System Functions The Vibration Isolation System is designed to do the following experiments: • To determine the natural frequency of the vibration system by (1) counting the number of vibrations per given time and/or (2) by performing vibration tests over wide ranges of excitation frequencies. • To investigate the effects of the springs on the vibration transmission from the system to the system frame (the floor), which can be applied to the design of engine mounting in the auto industry. This can also be applied to the isolation of machines to another precision machine through the floor (the foundation). • To isolate the vibration of the system by attaching a spring mass system to the vibration system.

5. Mechanical Design Required Materials • Stainless Steel Rods • Stainless Steel Sheets • Springs • Ball Bearings • Drum • Belt • Angle Brackets

6. Mechanical Design • The base will serve as the foundation for our vibration elimination system • We enlarged our base from our initial design in order to provide maximum stability (20”x12” to 40”x16”) and decided on it being ½” thick

7. Mechanical Design • The frame and poles will serve as the backbone of our system • The cage which houses the DC motor and unbalanced rotating mass will be limited to vertical motion by the two rods extending the height of the system • The rods are held in place by the frame at both the top and bottom

8. Mechanical Design • The cage will consist of 5 ¼” thick cuts of sheet metal to form an open faced rectangular cube • To allow seamless vertical motion the 4 openings on the top and bottom of the cube will have linear motion ball bearings that will run along the two support poles • Inside of the cage will be a drum with a mass attached to it, that when rotating will cause the excitation of the cage along the poles • The drum will be attached to separate rod which will be connected by a belt to our DC motor • It will be allowed to spin by a rotating ball bearing located in the back wall of the cage

9. Mechanical Design • To add even more rigidity to our system we have placed 8 total 90° angle brackets • Four in the top inside corners and four on the outside bottom corners • We also added a pole support on each side of the system to make certain there will be no vibration in the system other than the desired cage excitation

10. Materials • ¾” 304 Stainless Steel Rods • Each rod is 36” long. • Tensile Strength = 85,000 psi • Yield Strength = 35,000 psi • ASTM A182 & ASTM A479 Specifications

11. Materials • 5/8” x 9” Zinc-plated Steel Springs • Can safely support 8.2 lbs. • Will be connected to the cage that houses the DC motor, ball bearings, and the drum. • Cage weighs 7.2 lbs.

12. Materials • Steel 90 degree angle brackets • 1.18" x 1.18“ • Will go in the corners of the frame of the system to provide support. • Will also connect the base to the frame.

13. materials • Linear Motion Ball Bearings • Steel cage • Bore diameter = 0.765” • Load capacity = 270 N • Will be used to minimize friction between the cage and the rods.

14. Materials • Two hole strap • Galvanized Steel • Will be used to secure the DC motor in place inside the cage.

15. Design Calculations • Calculating Stiffness of the rods • Calculating Tensile Stress

16. Design Calculations • Calculating the spring constant

17. Design calculations • Calculating the displacement of the spring

18. Design calculations • Calculating the Mass Moment of Inertia at the center of the rods

19. Design calculations • Calculating the deflection of the rods under load

20. Design calculations • Calculating the deflection of the rods under load

21. Design calculations • Calculating the deflection of the rods under load • Using the Superposition theorem, we had to combine both deflections because of the two loads.

22. Design Calculations Calculating Mass Moment of Inertia for the DC motor • kg-

23. Calculations Calculating Mass Moment of Inertia for the Drum • kg-

24. Motor Control Required Materials • DC Motor • Arduino Board • H-Bridge • Wires • PC with Arduino program • Potentiometer

25. Motor Control Arduino • One Arduino micro-controller is used in our system as a real-time control computer, which is connected to a laptop computer for uploading the program.

26. Motor control H-bridge • Allows us to control the torque and thus the speed and rotational direction of the DC motor.

27. Motor control DC motor • The DC motor allows us to turn electrical energy into rotational mechanical energy. • It is the source of energy for our rotating mass in the system.

28. Motor Control • This code allows us to run the DC motor counter clockwise between values 0-500 and clockwise from values 600-1023. • The DC motor is turned off between values 501-599. • It also allows us to control how fast it spins in both directions.

29. Accomplishments Alex Mills • Developed preliminary hand sketches of initial design for system • Transferred sketches to SolidWorks to acquire three-dimensional models of each component • Researched real world parts to utilize inside of design • Assembled system with the individual parts working together • Improved upon design to satisfy safety and operational requirements

30. Accomplishments Monroe McCarty • Designed the ball bearings in SolidWorks. • Based on what we wanted for our system, chose the most suitable DC motor for the system. • Using superposition theorem, calculated the max deflection at the center of the rods. • Calculated the spring constant. • Calculated the natural frequency of the system. • Calculated the spring constant for the rods • Found products in the market we will build our design out of next semester. • Assisted in the design of the system

31. Accomplishments Zachary Kamm • Calculated the mass moment of inertia for the DC motor. • Calculated the mass moment of inertia for the Drum of our rotating mass. • Designed Visio diagrams for our calculations including the DC motor, Drum, first rod, and second rod. • Created a design of our Arduino based motor control system using TinkerCad. • Created a code in Arduino that allows the motor to run clockwise and counterclockwise and allows us to control the voltage going to the DC motor.

32. First Semester Timeline

33. Continuing Work • After this semester, we will be continuing to work on calculating and designing the gear ratio set-up between the DC motor and rotating drum. • We will also continue working on the motor based control so that it will allow us to set it to a certain number of RPMs. • Next semester, our goal is to build the mechanical system and to troubleshoot any problems, while continuing to put safety first into the design.

34. Works Cited • Texas Instruments, Inc. “Pin Configuration and Functions.” SN754410 Quadruple Half-H Driver. January 2015, http://www.ti.com/lit/ds/symlink/sn754410.pdf • Youngblood, Tim. “How To Control a DC Motor with an Arduino.” All About Circuits, 7 July 2015, www.allaboutcircuits.com/projects/control-a-motor-with-an-arduino/.