1. Codey Lozier Christian Thompson Advisor: Dr. Mohammad Saadeh
Stability Control System for a Propeller Powered by a Brushless DC Motor (BLDC)
Codey Lozier
Christian Thompson
Advisor: Dr. Mohammad Saadeh

2. Introduction Control Systems Stability Control System Setup Objectives
Components of Stability Control System
Current Progression
Future Progression

3. Control Systems
Goal is to modify a system so it behaves in a desirable way over time
Arrows (signals) represent vector-valued functions of time
Basic Control System
Plant
Controller
Sensor
r- reference input
v- sensor output
u- actuating signal
d- external disturbance
y-measure signal
n- sensor noise

4. Stability Control System Setup

5. Stability Control System Modification
Old Shaft
New Shaft

6. Objectives
A brushless DC motor is attached to a propeller, and fixed onto the end of a horizontal beam.
A shaft will be fixed onto the horizontal beam creating a 90 degree angle
The opposite end of shaft will be attached to rotary encoder.
When the motor is energized, the propeller will produce a lift force that will stabilize the beam
Every time the motor rises or falls the shaft connected to the rotary encoder rotates
This “index” value will be used as an error signal

7. Arduino Mega 2560 Microcontroller board based on the ATmega2560
Contains 16 analog input pins
Contains 54 digital I/O pins
14 digital I/O can be used for PWM
User friendly programming environment

8. Brushless DC Motor (BLDC)
Fixed on shaft coupler
Goal is to use the propeller to create a lift force
Electrically commutated, does not use brushes
Powered using brushless speed controller
Commutation is induced through PWM

9. Brushless DC Motor Modifications
Original propeller could not generate enough lift force
Had to be replaced with 8 x 4.5 carbon fiber (10g) propeller
New propeller generates force that can stabilize the beam

10. Propellers
Carbon Fiber
Weight: 10 g for each propeller
Size 8 X 4.5

11. Lift Force
Of the four forces of flight, we are only concerned with two:
Lift Force and Weight Force
Opposing forces
The airfoil of an airplane’s wing is just like a propeller blade

12. Schematic of Air Flow Through the PropellerY X

13. Pressure Variation Along Slipstream
P2 < P1 & P3 > P4 = P1 = Patm

14. Lift Force Continued
Air under the propeller blade, moves slower and exerts more of a force than the air moving above the blade.
Force under the blade is greater than the force above the blade

15. Brushless Speed Controller
Electronic speed controller (ESC)
Powers motor (17Vdc)
Used in high power RC systems
Receives PWM signals from Arduino Mega

16. Brushless Speed Controller
Potentiometer can be used to change the frequency and duty cycle of PWM
Change in resistance increase/decreases speed of motor

17. Image Retrieved from 3133 Micro Load Cell CZL635 datasheet
A load cell is a force sensing element
Small components called strain gauges mounted in precise locations
Change in electrical resistance
Image Retrieved from:
Image Retrieved from 3133 Micro Load Cell CZL635 datasheet

18. Phidget Bridge Contains 4 Wheatstone Bridges USB interface ( 2 )
Amplifies signal sent from micro load cell ( 1 )
Demo applications are provided
Users can develop own applications
Image Retrieved from 1046 PhidgetBridge 4-Input Product Manual

19. Microload Cell Calibration
Used demo program provided by manufacturer
Performed several trials
Values produce were stable
Need to amplify signals being sent from load cell

20. YUMO Rotary Encoder Measure change in angle, direction, and speed
Resolution of 2000 pulses/rev
Manufacturer provides a demo
application
Produces a signal that represents an
“index” or angular position
Signal for direcion a

21. YUMO Rotary Encoder Shaft is stabilized with pillow block
Device is fixed to table
Encoder is interfaced with data acquisition device

22. Encoder data acquisition device
Designed to measure 4 incremental encoders
USB interface
Interfaced with rotary encoder
Includes application demo
Users can develop their own applications
Image retrieved from US Digital USB4 Encoder Data Acquisition USB Device User Manual

23. Current Progression The experimental setup has been established
Two couplers and two rods are connected to the encoder’s shaft.
The load cell was calibrated using a calibration weight set.
Selected propeller for the desired lift force
Measure lift force of BLDC using micro load cell (current)
Youtube Video

24. Future Progression June - August 2014
Setup a control algorithm with the following components:
The goal is to stabilize the output rod in the horizontal position
The encoder reading serves as a good reference point. It can be used as feedback
The driving signal is the error in encoder reading (difference between reference and actual readings)
This error controls the magnitude of the BLDC operating voltage

25. Future Progression September-November 2014
Include a second BLDC on the other end of the rod. Repeat the control algorithm for the new two-BLDC motors system
Integrate all components using a data acquisition system, and a control algorithm in real time environment (e.g. LabVIEW)