Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Quadrocopter

873 views

Published on

Published in: Business
  • Be the first to comment

Quadrocopter

  1. 1. Quadrocopter Kyle Bartholomew
  2. 2. What is a quadrocopter? • Like a helicopter with 4 blades. • 2 blades spin clockwise, 2 spin counterclockwise = zero net torque • Motion Control Unit – Keeps the copter stable without human control. • Power system – Based on lithium polymer battery
  3. 3. Power System Motors + - Motor Controllers LiPo Battery 5V Regulator Arduino
  4. 4. Outrunner Brushless Motors AC Power
  5. 5. Motion Control Unit • Miniature computer (Arduino microcontroller) – Runs at 16Mhz (Your computer runs about 200 times faster) – Takes electrical signals in, does math, spits out more electrical signals. • IMU – Inertial Measurement Unit – 3-axis gyroscope and accelerometers. Motor Controllers Arduino RF Receiver IMU
  6. 6. Accelerometers or Gyros? • What do you use to measure the angle of the copter relative to the ground?
  7. 7. 3.3V Accelerometers • 3-axis, measures acceleration – When incidental acceleration is small enough, it measures just the acceleration of gravity. – Absolute angle relative to earth. • Highly susceptible to noise: ∆0.11V = ∆30° 10 bit ADC = 1024 steps of measurement 3.3V/1024 = .00322V/step 1g 1.95V 1g 0g 30deg 0g 1.65V 1.65V (30°/0.11V)*(.00322V/step) = 0.88°/step 0V
  8. 8. Gyroscopes • • • • 3-axis, measures angular velocity (w) Integrate w over time to get angle Good at instant angle measurements Bad at absolute angle measurements because it drifts. • Small error in w leads to big error over time.
  9. 9. Combining measurements • You want best of both with – High speed low noise measurements – Accuracy over long periods of time
  10. 10. Complimentary Filter • Combines accelerometer and gyro to produce a better angle measurement. • High pass filter on gyro and low pass filter on accelerometer. • Aka only long term for accelerometer and only short term for gyro.
  11. 11. PID Control • Need to go from angle to motor output. • Based on idea of error from setpoint. • The ideal method is PID control – Proportional Integral Derivative. • Proportional – Controls the now • Integral – Controls by looking at the past • Derivative – Controls by looking forward to the future. Error = θdesired-θcurrent
  12. 12. Complimentary Filter Accelerometer Low Pass Filter Angle Gyroscope PID P Coefficient Integration High Pass Filter Integration Derivative I Coefficient D Coefficient Motor Output (200hz)
  13. 13. How does it move? CW Hint: r X F CCW CCW CW
  14. 14. I•ɑ
  15. 15. Going further • Many people add other fancy things to their quadrocopters: – GPS – Altitude Sensor (Barometer) – Camera – FPV (First Person View) – Tracking Systems to do crazy stuff like flips and multiple copter coordinated dances.

×