1. Quadcopters A CEV Talk

2. Agenda Flight PreliminariesWhy Quadcopters The Quadcopter SystemStability: The NotionSensors and FusionControl AlgorithmsThe Way Ahead

3. Flight Preliminaries

4. 4 movements Altitude – Up – Down Roll – Left – Right Pitch – Front – Back Yaw – Heading

5. Altitude Hover

6. Altitude Up

7. Altitude Down

8. Roll

9. Pitch

10. Quick question Correct Wrong

11. Yaw

12. Why Quadcopters?

13. Flight is fun!

14. Simplicity

16. However Scaling up, 4 Simple Mechanisms 1 Relatively complex mechanism

17. 4 rotors 4 rotors harder to control than one

18. Nevertheless Mechanical Simplicity + Electronic Stabilization win

19. Perks Less stable = learn more control theory. Less kinetic energy per motor(rotor). You wont lose your fingers.

20. Done Flight Preliminaries Done Why Quadcopters The Quadcopter SystemStability: The NotionSensors and FusionControl AlgorithmsThe Way Ahead Agenda

21. The Quadcopter System [Q]

22. Open Loop

23. Stability: The Notion Mind SenseTake action

24. Done Flight Preliminaries Done Why Quadcopters Done The Quadcopter System Done Stability: The NotionSensors and FusionControl AlgorithmsThe Way Ahead Agenda

25. Inertial Measurement Unit (IMU) IMU AccelerometerGyroscope

26. Angle calculation: Accelerometer Inclination from an axis can be calculated using the component of gravity along that particular axis.

27. Angle calculation: Gyroscope Gyroscopes provide angular rate in degrees per second. The angle with a certain axis can be calculated by integrating the angular velocity with respect to that axis over the sampling period.

28. IMUs are not perfect! Accelerometers : When in motion, the acceleration of the robot affects the acceleration measured by the accelerometer. Gyroscopes : Due to manufacturing limitations, signal drift often accompanies MEMS gyros. When integrated over time, this drift leads to considerable error.

31. Complementary filter Simplest filter for IMUs Corrects Gyro drift by including a certain component of angle measured by the accelerometer in angle measurement Angle= 0.98*(Gyroscope Angle) + 0.02*(Accelerometer angle)

33. Kalman filter

35. Done Flight Preliminaries Done Why Quadcopters Done The Quadcopter System Done Stability: The Notion Done Sensors and FusionControl AlgorithmsThe Way Ahead Agenda

36. Control Algorithms

37. Proportional-Integral-Derivative : An Intuition P roportional term generates output based on error I ntegral term generates output based on bias in error D erivative term generates output based on speed of error variation Mathematical procedures to tune PID constants (very hard work): -- Root locus method -- Bode plots -- Nyquist Criterion -- Zeigler Nicols Algorithm Method which usually works: -- Trial and Error (video)

38. Inside The Controller Set point Filtering and Data fusion PID error Control signals for ESC, which will in turn command motors Computed Angles Measured Angular rates And acceleration

39. The Closed Loop Quadcopter dynamics Sensors Controller

40. Done Flight Preliminaries Done Why Quadcopters Done The Quadcopter System Done Stability: The Notion Done Sensors and Fusion Done Control AlgorithmsThe Way Ahead Agenda

41. Onward we fly…

43. Quads in aerial photography, delivery systems, search and rescue…

44. Onward we fly… Better (Nonlinear) Control Accurate estimators SLAM Motion Planning

45. Better Control Non linear control (V) Robust control Adaptive control Stochastic control

46. Better Control

47. Accurate Estimators Implementing Extended Kalman filter Third order stochastic filter Multi state constraint Kalman filter for vision aided navigation

48. So Far So Good Hardware Stability Movement Interaction?

49. Quad’s eye view What does the world look like? [MAPPING] Where am I? [LOCALIZATION] A chicken and Egg problem

53. Some Statistics Vijay Kumar labs – 7 post doctoral researchers – 5 Research scientists – 17 Ph.D. students – Needless to mention masters and undergraduate students Raffaello D’ Andrea (Q) – 17 research students and professors working together

55. Research Exploration Investigation Experimentation Inquest Fact finding Analysis

56. “There’s an infectious feeling within us that research can solve almost any problem..” “There’s an infectious feeling in Stanford that innovation can solve almost any problem..”[Q]

57. Robotics EC Mechanical Engg Computer Science Electrical Engg

58. Internships Areas of interest – Control Algorithms – State Estimation – SLAM December 11 th to 26 th [tentative] 6 to 12 interns – 3 Paid Link at www.robotick.org