Autonomous Robotic Boat Platform

Transcription

1 Autonomous Robotic Boat Platform Team: Ryan Burke, Leah Cramer, Noah Dupes, & Darren McDannald Advisors: Mr. Nick Schmidt, Dr. José Sánchez, & Dr. Gary Dempsey Department of Electrical and Computer Engineering February 24 th, 2015

2 Presentation outline Background Objective Block diagram Division of labor R. Burke GPS/compass finalization and navigation system L. Cramer Detecting buoys with computer vision N. Dupes Motor controller D. McDannald Central processor 2

3 Presentation outline Background Objective Block diagram Division of labor R. Burke GPS/compass finalization and navigation system L. Cramer Detecting buoys with computer vision N. Dupes Motor controller D. McDannald Central processor 3

4 Objective Design and build an autonomous boat platform Versatile Robust 8 th annual RoboBoat competition (Virginia Beach, VA) Competition time frame: July Images taken from [1]. 4

5 Catamaran Boat Design Image taken from [1]. 5

6 6

7 Division of labor Task Central processing Image processing GPS/compass interfacing Motor control Remote control Navigation Person assigned to task Darren McDannald Leah Cramer Ryan Burke Noah Dupes Darren McDannald Ryan Burke, Darren McDannald 7

8 Presentation outline Background Objective Block diagram Division of labor R. Burke GPS/compass finalization and navigation system L. Cramer Detecting buoys with computer vision N. Dupes Motor controller D. McDannald Central processor 8

9 Gantt chart 9

10 Gantt chart 10

11 GPS/compass unit block diagram 11

12 GPS/compass unit block diagram 12

13 Acknowledge message GPS initialization MCU Change baud rate to kbaud GPS 13

14 Acknowledge message GPS initialization MCU Baud rate changed successfully GPS 14

15 GPS and compass data testing GPS data Longitude Latitude Compass data Standard deviation 2.48E E Variance 6.15E E Number of samples Average value Actual value

16 Navigation system operation 16

17 Navigation system operation 17

18 Navigation system operation 18

19 Navigation system operation 19

20 Navigation system operation 20

21 Navigation system operation 21

22 Navigation system operation 22

23 Navigation system operation 23

24 Navigation system operation 24

25 Navigation system operation 25

26 Navigation system operation 26

27 Navigation system operation 27

28 Navigation system operation 28

29 Navigation system operation 29

30 Navigation system operation 30

31 Navigation system operation 31

32 Progress 32

33 Progress 33

34 Presentation outline Background Objective Block diagram Division of labor R. Burke GPS/compass finalization and navigation system L. Cramer Detecting buoys with computer vision N. Dupes Motor controller D. McDannald Central processor 34

35 C++ Images from: Amazon.com Bit-tech.net Willowgarage.com 35

36 Competition obstacles Image from: 36

37 Buoy identification flowchart with circle detection 37

38 Circle detection buoy identification results Hough transform Percentage of frames True positive (buoy detected) 80% False positive (incorrect buoy detected) 13.5% False negative (buoy not detected) 6.5% 38

39 Buoy identification flowchart with blob detection 39

40 Blob detection with buoy identification results Blob detection Percentage of frames True positive (buoy detected) 33% False positive (incorrect buoy detected) 62% False negative (buoy not detected) 5% 40

41 Project task progress 41

42 Presentation outline Background Objective Block diagram Division of labor R. Burke GPS/compass finalization and navigation system L. Cramer Detecting buoys with computer vision N. Dupes Motor controller D. McDannald Central processor 42

43 T100 thruster Brushless DC (BLDC) Provides 2.36 kgf ( 5.2 lbf ) of forward thrust Sensorless T100 thruster size comparison obtained from[1] 43

44 A4960 pre-driver configuration The Allegro pre-driver A4960 motor controller with MCU input. Image obtained and modified from[5] Pre-Driver 44

45 A4960 pre-driver configuration The Allegro pre-driver A4960 motor controller with MCU input. Image obtained and modified from[5] Pre-Driver 45

46 Digital commutation for a brushless motor Utilize a three phase configuration Rotor Position( ) High Side Off Low Side High Side Off Low Side High Side Off Low Side Figure 1: Y-configuration of a three phase motor obtained from[2] Figure 2: Three phase digital commutation obtained from[3] 46

47 MOSFET driver configuration 12V Legend H- High Side Driver L- Low Side Driver A- A Phase B- B Phase C- C phase H-A H-B H-C B A C L-A L-B L-C 47

48 Current path for the driver configuration 12V Legend H- High Side Driver L- Low Side Driver A- A Phase B- B Phase C- C phase High-Side Current Path Low-Side Current Path H-A L-A H-B L-B H-C L-C B A C 48

49 Current path for the driver configuration 12V Legend H- High Side Driver L- Low Side Driver A- A Phase B- B Phase C- C phase High-Side Current Path Low-Side Current Path H-A L-A H-B L-B H-C L-C B A C 49

50 Current path for the driver configuration 12V Legend H- High Side Driver L- Low Side Driver A- A Phase B- B Phase C- C phase High-Side Current Path Low-Side Current Path H-A L-A H-B L-B H-C L-C B A C 50

51 Current path for the driver configuration 12V Legend H- High Side Driver L- Low Side Driver A- A Phase B- B Phase C- C phase High-Side Current Path Low-Side Current Path Coil Measuring BEMF H-A L-A H-B L-B H-C L-C B A C 51

52 Utilizing back electro-magnetic force (BEMF) Measured at common terminal, S, between the high and low side MOSFETS Used to determine the rotor position and speed of the BLDC motor S A4960 outputs a frequency varying TACHO signal proportional to the rotors speed 52

53 Latest progression of Gantt 1 ID 1 Task name Research motor controller and configuration Nov 2014 Dec Jan 2015 Feb Mar 2 Motor controller circuit design and testing 3 Assembly of motor configuration on boat frame 4 Progress presentation Schedule Time Completed Milestone 53

54 Slide 53 1 Continue designing and building the A4960 motor controller configuration Expected delivery of T100: January 2015 Research and design the controls algorithm for the diamond thruster configuration -ndupes,

55 Presentation outline Background Objective Block diagram Division of labor R. Burke GPS/compass finalization and navigation system L. Cramer Detecting buoys with computer vision N. Dupes Motor controller D. McDannald Central processor 54

56 Serial communication A C++ class to access a subsystem through serial Sets attributes and can have multiple instances of each connection Able to request and receive data 55

57 Project filing system Easy compilation using a make file Saves time by only compiling when items have been changed Related files in single folder 56

58 Project filing system Easy compilation using a make file Saves time by only compiling when items have been changed Related files in single folder 57

59 Project filing system Easy compilation using a make file Saves time by only compiling when items have been changed Related files in single folder 58

60 Project filing system Easy compilation using a make file Saves time by only compiling when items have been changed Related files in single folder 59

61 Boat trial script A C++ class takes care of the naming of each frame Script makes video automatically at the end of each run Compresses the runs folder Script asks for a description of the surroundings to help testing 60

62 Used TinyXML to configure boat Use of xml files to make to boat easily configurable and on the fly Used to keep compilation times down 61

63 GPS class Request data from GPS and compass data Store the data Path planning Motor and speed commands Data will be used to navigate between one location to another 62

64 Motor class Takes in a speed, direction, and amount of pivot Outputs a string that corresponds to the four motors on the boat calculate(speed, direction, pivot); Converts direction and pivot to a vector for each motor Outputs string over serial *m1: 120 m2: 35 m3: 25 m4: 25 63

65 Schedule 64

66 Future Work Currently working on a navigation system Finish making the motor class and test its operation Implement an accurate time base Threading to process the different systems 65

67 Autonomous Robotic Boat Platform Team: Ryan Burke, Leah Cramer, Noah Dupes, & Darren McDannald Advisors: Mr. Nick Schmidt, Dr. José Sánchez, & Dr. Gary Dempsey Department of Electrical and Computer Engineering February 24 th, 2015

68 Appendix 67

69 Motor Configuration Selection Diamond configuration Consists of four motors Allows for strafing Allows for 360 rota on Diamond configuration on a catamaran platform 68

70 Transistor Configuration For Three Phase Drive Three phase drive circuit consisting of six transistors, six flyback diodes, and a y-configuration three phase motor obtained from[4] 69

71 Power Consumption Of Transistors Type MOSFET BJT IGBT Power consumption calculation Typical values Power consumption of a 11.5 A drive using typical transistor values 70

72 References [1] Blue Robotics. (2014). T100 Thruster [Online]. Available: [2] Global Spec. (2011). Synchronous Motor Grounding [Online]. Available: [3] Embedded. (2008). Designing a MCU-driver permanent magnet BLDC motor controller: Part 1 [Online]. Available: [4] Analog Dialogue. (2008). High Current Sensing [Online]. Available: [5] Allegro MicroSystems. (2014). A4933: Automotive 3-Phase MOSFET Driver [Online]. Available: [6] St. Cyprain s Greek Orthodox Primary Academy. (2014) [Online]. Available: [7] SparkFun Electronics. (2014). Dual Full-Bridge Driver [Online]. Available: [8] Vishay. (2011). IRF520 Power MOSFET [Online]. Available: 71

73 Image Processing-Rectangle Detection Purpose of Research and Testing: Determine How to Detect Polygons Contained within an Image Research OpenCV Utilizes Contours For Detection Of Polygons Contours: Outline or Enclosed Border of a Shape or Form The Contour Detection Algorithm Used By OpenCV: Topological Structural Analysis of Digitized Binary Images by Border Following by Satoshi Suzuki and Keiichi Abe[] MATLAB Testing Imcontour() Implementation Contour Algorithm Testing 72

74 MATLAB Imcontour()-Original Image Image obtained from[6] 73

75 MATLAB Imcontour()-Contour Detection 74

76 H-Bridges Purpose of Research and Testing: Understand the Benefits and Drawbacks of Using H-Bridges Features Bi-Directional Motor Control Four Transistor Configuration Provides Dynamic Breaking Capabilities Allows For Current Sensing 75

77 H-Bridge Testing L298 H-Bridge Contains Two Internal H-Bridge Configurations Two Enable Signals Allows for a 150w motor(50v, 3A Max Rating) Fly Back Diode: 1N4004 Motor 12V >2A While In Air 76

78 L298 H-Bridge Internal Configuration Image obtained from[7] 77

79 H-Bridge Free Running Motor Stop 78

80 H-Bridge Dynamic Motor Stop 79

81 Benefits: Simple Configuration Easily Controllable Provides Bi-Directional Control H-Bridge Conclusion Drawbacks: Large Power Dissipation The Internal BJT Configuration Has Constant Power Dissipation Limits Design 80

82 Choosing A Transistor Type There Are Two Primary Transistor Types: MOSFET and BJT MOSFET Output Is Controlled By Gate Voltage Positive Temperature Coefficients Power Dissipation Depends On Internal Resistance High Gate Capacitance Higher Switching Frequencies BJT Output Is Controlled By Base Current Negative Temperature Coefficients Power Dissipation Depends Terminal Voltage Differentials Low Gate Capacitance Lower Switching Frequencies 81

83 Choosing A MOSFET IPP040N06N R DS max=4 mω V DS max=60 V I D max= 80 A Q G max= 44nC IPP060N06N R DS max=6 mω V DS max=60 V I D max= 40 A Q G max= 32nC IRLB8721PbF R DS max=8.7 mω V DS max=30 V I D max= 44 A Q G max= 13nC IRLB8748PbF * * R DS max=4.8 mω V DS max=30 V I D max= 44 A Q G max= 23nC * * Indicates the current choice for the MOSFET configuration 82

84 PWM Driven Transistor Configuration Purpose of Research and Testing : Design a Transistor Switch Configuration Driven by a Microcontroller Generated PWM Controlled by an Analog Input. 83

85 Block Diagram For System 84

86 Design And Testing IRF520 VDS Max = 100V RDS(ON) Max = 0.27 Ω Max Gate Charge = 16 nc Output Characteristics of the IRF520 obtained from[8] Atmega168 Microcontroller Minimum Pin Output Voltage = 4.2V Maximum Pin Output Current = 40mA 2N2222A Hfe(Gain) = 75 Max VCE(Sat) = 1.6V Max VBE(Sat) = 2.6V 85

87 Observations of the Gate Input for the IRF520 Gate input with Rc equal to 1.2KΩ Gate input with Rc equal to 10KΩ Gate input with Rc equal to 100KΩ 86

88 A4960 Specs Absolute Ratings Max Load Supply Voltage: 50 V Max Logic Supply Voltage: 6 V Max Sink Current: 150 ma Max Gate Output Turn on/off: 20 ns Max System Clock Period: 57 ns (17.5 MHz) Minimum Input Pulse Filter Time: 500 us (2 KHz) 87

89 Three Phase Back EMF Output Image obtained from [5] 88

90 IRF520 Circuit Configuration Circuit 1: Motor Drive IRF520 Configuration Circuit 2: IRF520 Test Configuration 89

91 Circuit Design for the Transistor Switch Configuration 90

92 = + = + [source: wikipedia] 91

93 [source: wikipedia] 92

94 [source: wikipedia] 93

95 = + = + 94

96 95

97 21HT Hough Transform Method Reduces the amount of memory required. Uses edge direction Two step process 1.) The center of any given circle is the intersection point of all the normal lines from the circle edge. A 2-dimensional array is used to record the "votes" along the normal line of each detected edge point. 2.) "To identify the radius of circles, the distance of each point from a candidate center is calculated and a radius histogram is produced." PROS: This method is low on storage space. Only a 2-d array is used and a 1-d histogram. CONS: If the radius threshold is very low (i.e. The 21HT is being used to detect very small circles) there is a risk of many false peaks occurring in step 1. This can increase the amount of computational work necessary in step 2. 96

98 Gaussian Filtering, =

99 OpenCV Results using: RGB Colorspace Gaussian Filtering Canny Edge Detection Hough Transform 98