SAE Formula Car Data Acquisition & Display System. Joseph Groe, Michelle Ohlson, & Miles Homler Advisor: Professor Gutschlag

Transcription

1 SAE Formula Car Data Acquisition & Display System Joseph Groe, Michelle Ohlson, & Miles Homler Advisor: Professor Gutschlag

2 Agenda Problem Background Problem Statement System Diagram Project Functional Requirements Division of Labor Discussion of Subsystems Summary and Conclusion References 2

3 Problem Background Bradley SAE Formula Car Race Mechanical Engineering Department attempts to race every year Assist Bradley SAE Formula Car Anticipate problems before they become serious or dangerous Engine failure - temperature or oil pressure Safely operate formula car Seized engine during racing due to overheating or loss of oil pressure Improve testing capabilities before competition Give opportunities to SAE team to foresee performance issues 3

4 Problem Statement A data acquisition system was built to assist the Bradley University mechanical engineering team in the annual SAE formula car race. The intent of the system was to permit the team to monitor the car for warning signs associated with various failures during testing. The system uses a microcontroller to read data from sensors on the car, then converts the data to the proper format before sending it to the driver s display and a wireless transceiver that transmits the data to a track-side laptop. 4

5 System Diagram 5

6 Project Functional Requirements Acquire data from the sensors Display critical sensor data on the in-car touch screen display for the driver to view Transmit the data to a track-side laptop Display sensor data on the track-side laptop for the pit crew Save the data for later viewing 6

7 Division of Labor Joseph Groe - Display software, sensor inputs Miles Homler - Sensor inputs, wireless transceiver outputs Michelle Ohlson - Wireless transceiver software, computer GUI, data storage and retrieval 7

8 Division of Labor 8

9 Display Subsystem Requirements Receive sensor values over CAN bus Display sensor values to the driver via gauges on the display Display arbitrarily varying values during Demo Mode for judging purposes 9

10 Parker IQAN MD4-7 Specifications 4 CAN Buses 2 Ethernet Ports 2 Voltage Inputs 8 Digital I/O Programmed from Parker IDE IQANdesign IQANsimulate 10

11 CAN Communication CAN Data Frame Example Used in numerous vehicle applications Multiple systems (nodes) per vehicle Ease of communication between each system Low cost for hardware 500 kbps 11

12 Messaging Spreadsheet Name CAN ID Minimum Value Maximum Value Label Bits Bit Offset Units/bit Engine Coolant Temp Fahrenheit Engine Oil Temp Fahrenheit Engine Oil Pressure PSI RPM RPM Potentiometer Inch Potentiometer Inch Potentiometer Inch Potentiometer Inch

13 IQANdesign High-level system diagrams Define each subsystem Define communication schemes and protocols Create display screens and tie values to the gauges 13

14 IQANdesign CAN Frame defined Each message is defined In each frame Other I/O channels Voltage in Digital in 14

15 IQANdesign Frame defined Bits of frame defined 15

16 IQANdesign Place gauges and interactive controls Define gauges and controls 16

17 IQANdesign Gauge defined by input channel Min/Max also defined Custom gauges available 17

18 Display Pages & Controls Race Mode Demo Mode 18

19 Demo Mode Create internal signal for Demo Mode gauges Max value for oil pressure sensor PSI Max value for suspension sensors - 12 in. Max value for RPM sensor RPM Max value for coolant and oil sensor F 19

20 IQANsimulate Simulate display on computer Simulate CAN messages 20

21 IQANsimulate Manipulate CAN messages at will See outcomes before release 21

22 Downloading Project to Display Send Project to Display USB CAN Ethernet Internet Get Project Capabilities Project protection 22

23 Wireless Transmission & LabVIEW GUI Subsystem Block Diagram Subsystem Functional Requirements Wireless Transceivers LabVIEW GUI Test Results 23

24 Subsystem Block Diagram 24

25 Subsystem Functional Requirements Wireless Transmission Range of at least 1 mile Track-side Laptop LabVIEW GUI Communicate with RM024 wireless transceiver connected to track-side laptop Data Display Data storage and retrieval Data storage limited only by laptop memory 25

26 Wireless Transmission DVK-RM024-FCC Wireless Transceiver Development Kit (2) RM024 Pluggable 125mW transceivers with integrated antenna and U.FL connector (1) EIA-232 serial adapter board (1) USB serial adapter board (1) DB9 (F) to DB9 (F) EIA-232 cable (1) USB cable 6 ft. (2) 2.4GHz 1/2 dipole antennas 26

27 Wireless Transmission RM024 Range: 2.5 miles with integrated antenna Laird BlackChip MAF95029 Supply Voltage: V ± 50 mv ripple Operational Temperature: -40 C to 85 C RF Technology: Frequency Hopping Spread Spectrum Frequency Band: MHz 27

28 Wireless Transmission Data transmitted using packets Data is sent either when the packet is full, or when timeout occurs (2.5 ms) 28

29 Laird Configuration/Test Utility Free software from Laird Program and test RM024 wireless transceivers Provides option to save setups to a file Automatic configuration file version tracking 29

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32 Track-Side Laptop LabVIEW GUI LabVIEW full version - $1000 LabVIEW Student Edition - Free No known differences between full version and student version functionality 32

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36 Wireless & LabVIEW GUI Communication Instrument I/O Assistant Block LabVIEW was programmed to receive 8 unsigned 16-bit values followed by a newline Number of data bits must be a multiple of 8 LabVIEW can only handle bytes, not bits RM024 uses 8 data bits - not configurable 36

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38 LabVIEW Load from File Button Code 38

39 Wireless Transmission & LabVIEW Testing 1) 2) 3) 39

40 Test Results 40

41 Test Results Wireless communication established LabVIEW receives data, displays, saves, and graphs the data 41

42 Sensors and Microcontroller Subsystem Block Diagram Subsystem Functional Requirements Sensors Microcontroller Microcontroller Function Microcontroller Programming 42

43 Subsystem Block Diagram 43

44 Subsystem Functional Requirements Sensor data input to microcontroller Data converted to proper format for output Sensor data output to RM024 transceiver and IQAN display EIA-232 data is sent to RM024 CAN data is sent to IQAN 44

45 Sensors Total of eight sensors going to the microcontroller Current outputs: Voltage outputs: RPM Sensor AiM X05SNVS00 Engine Coolant Temperature Sensor Prosense TTD25N F-H Engine Oil Temperature Sensor Prosense TTD25N F-H Engine Oil Pressure Sensor Prosense PTD H Four string potentiometers Black Diamond LX-PA Potentiometers One for each wheel Sensors will connect to the eight pins of Port F on the AT90CAN128, which serves as an A/D converter 45

46 Sensors Current-to-voltage converter circuit: 46

47 Microcontroller Microcontroller chosen was an AT90CAN128 Chosen for CAN compatibility, to communicate with the IQAN display, as well as familiarity with Atmel Embedded on DVK90CAN1 development kit, which features two 9-pin serial output ports, one EIA-232 and one CAN port 47

48 Microcontroller EIA-232 to transceiver CAN to display The board is powered by an external 9V battery power supply. The board has a switch to select regulated 3V or 5V supply to the microcontroller 48

49 Microcontroller Function AT90CAN128 will read values from sensors (those with current outputs will be conditioned with a current-to-voltage converter prior to the microcontroller ADC) AT90CAN128 includes a 10-bit ADC Convert values from sensors to data that can be read by display and transceiver 49

50 Microcontroller Programming EIA-232 Configuration Initialize with clock speed of 8MHz (system default clock speed of 8MHz and prescaler set to 16), baud rate of 9600 relates to clock before prescaler Use registers to enable serial output, 8 bit characters with no parity, 1 stop bit, and no handshaking 50

51 Microcontroller Programming CAN Configuration Using same internal clock on AT90CAN128 Set to 500 khz with prescaler of 16 to match IQAN display Microcontroller takes sensor data read from the 10-bit ADC 8 sensors generate 80 total data bits CAN frames are 8 bytes, system uses two frames One CAN frame = 64 bits, each frame holds 40 bits of sensor data One frame holds the engine sensor data, the other holds the suspension data 51

52 Messaging Spreadsheet Name AT90CAN128 Sends: Minimum Value Maximum Value Label Datatype Units/Bit Engine Coolant Temp Engine Coolant Temp Fahrenheit uint Fahrenheit uint16 1 Engine Oil Temp Engine Oil Temp Engine Oil Pressure Engine Oil Pressure PSI uint16 1 RPM RPM RPM uint16 1 Potentiometer 1 Pot value * Inch uint Potentiometer 2 Pot value * Inch uint Potentiometer 3 Pot value * Inch uint Potentiometer 4 Pot value * Inch uint

53 Summary and Conclusion Bradley SAE Formula Car Race Mechanical Engineering Department attempts to race every year System will assist Bradley SAE Formula Car Team Anticipate problems before they become serious or dangerous Safely operate formula car Improve testing capabilities before competition Log data for future reference when examining car 53

54 Summary and Conclusion Accomplishments Wireless Communication Established Fully functional track-side laptop GUI Fully functional in-car display Future Work Sensors System Testing 54

55 References

56 Appendix A - CAN Communication Source: Texas Instruments - Pg 3 56

57 Appendix B - RM024 57

58 Appendix B - RM024 58

59 Appendix B - RM024 59

60 Appendix B - RM024 60

61 Appendix B - RM024 61

62 Appendix B - RM024 62

63 Appendix B - RM024 DVK Board 63

64 Appendix B - RM024 DVK Board 64

65 Appendix B - RM024 Packets 65

66 Appendix B - RM024 Packet Header Info 66

67 Appendix C: Dipole Antennas Full-wave dipole A full-wave dipole antenna consists of two half-wavelength conductors placed end to end for a total length of approximately L = λ. The additional gain over a half-wave dipole is about 2 db, but the impedance is much higher than a half-wave dipole making it more complicated to match with ordinary, low impedance RF equipment and cabling. Half-wave dipole A half-wave dipole antenna consists of two quarter-wavelength conductors placed end to end for a total length of approximately L = λ/

68 Appendix D - Previous SAE Formula Car Teams 68

69 Appendix D - Previous SAE Formula Car Teams Both transceivers have adequate range, and can communicate using EIA-232. The RM024 is available in a development kit with everything needed for the project. The AC M does not come in a kit and requires antennas that must be ordered separately. The RM024 is cheaper, has a higher serial interface data rate, higher RF data rate, and it comes in a kit so that everything will certainly work together. 69

70 Appendix E - LabVIEW GUI Video 70

71 Appendix F - LabVIEW Graph Zoom Right-click the graph or chart and select Visible Items»Graph Palette from the shortcut menu. 71

72 Appendix F - LabVIEW Graph Zoom 6 zoom buttons Zoom to Rectangle With this option, click a point on the display you want to be the corner of the zoom area and drag the tool until the rectangle covers the zoom area. X-zoom Use this option to zoom in on an area of the graph along the x-axis. Y-zoom Use this option to zoom in on an area of the graph along the y-axis. Zoom In about Point With this option, click a point you want to zoom in on. Press and hold the <Shift> key to switch between Zoom In about Point and Zoom Out about Point. Zoom Out about Point With this option, click a point you want to zoom out from. Zoom to Fit Use this option to autoscale all x- and y-scales on the graph or chart. 72

73 Appendix G - Microcontroller Power Source 73

74 Appendix H - Sensor Characteristics AiM X05SNVS00 74

75 Appendix H - Sensor Characteristics Prosense TTD25N F-H 75

76 Appendix H - Sensor Characteristics Prosense PTD H 76

77 Appendix H - Sensor Characteristics Black Diamond LX-PA String Potentiometers 77