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Actuators & Sensors Team

Actuators & Sensors Team. Objectives: Operate actuators and sensors to carry out mission control and scientific data collection tasks. Requirements: Design sensor/controller interface hardware Members: Nathir Rawashdeh (lead), Garrett Chandler, Chenxing Wang, Srinivasa Patri & Z. Cai.

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Actuators & Sensors Team

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  1. Actuators & Sensors Team • Objectives: Operate actuators and sensors to carry out mission control and scientific data collection tasks. • Requirements: Design sensor/controller interface hardware • Members: Nathir Rawashdeh (lead), Garrett Chandler, Chenxing Wang, Srinivasa Patri & Z. Cai BIG BLUE II CDR University of Kentucky

  2. Section Outline • Deployed Sensors & Actuators • Ballistic Cutter Actuator Design • Risks and Testing BIG BLUE II CDR University of Kentucky

  3. Deployed Sensors & Actuators • Compass • GPS (navigation) • GPS (APRS communication) • Wing Strain • UV Sensor • Pressure (inflation tank, wing, absolute) • Temperature (wing, external & internal) • Accelerometers • High Current Switch BIG BLUE II CDR University of Kentucky

  4. Deployed Sensors & Actuators The following components are covered in the sections on Navigation & Communication: • Compass (for Navigation) • GPS (for Navigation) • GPS (for APRS communication) BIG BLUE II CDR University of Kentucky

  5. Deployed Sensors & Actuators The following sensors are being developed by the Mechanical Engineering. Necessary interface circuitry will be provided. • Wing Strain (scientific data) • UV Sensor (for wing curing process) • Pressure (inflation tank) see inflation group BIG BLUE II CDR University of Kentucky

  6. Deployed Sensors & Actuators Pressure (wing) • Sensor: MPX5100DP Case867c, “Motorola” • Range: 0 – 100 kPa (0 – 14.5 psi) • Output Range: 0.2 t 4.7 Volts • Size: 0.41 x 29.4 x 29.9 • Operating Temp: -40 to 125 ºC BIG BLUE II CDR University of Kentucky

  7. Deployed Sensors & Actuators Pressure (wing) … continued BIG BLUE II CDR University of Kentucky

  8. Deployed Sensors & Actuators Pressure (absolute) • Use: compute altitude • Sensor: 15PSI-A-4v from “All Sensors” • Size: 1.1” x 1.08” x 1.03” • Range: 0 ±0.3 to 15 psi • Output: Ratiometric 4V • Temp: -25 to 85ºC, 5 to 50ºC compensated BIG BLUE II CDR University of Kentucky

  9. Deployed Sensors & Actuators Pressure (absolute) … continued BIG BLUE II CDR University of Kentucky

  10. Deployed Sensors & Actuators Temperature (wing) • Wing temp. Important scientific data • Use MAX6674 thermocouple interface chip (?) • Size: 0.197” x 0.157” x 0.069” (5x4x1.75 mm) • Weight: < .035 oz. (< 1g) • Power Consumption: 1mA@3V • 8-pin SO Package,SPI- compatible serial interface • Range: 0°C to +128 °C @ 0.125 °C resolution • Accuracy: ±2 °C for the range 0 °C to +125 °C • Interface: SPI BIG BLUE II CDR University of Kentucky

  11. Deployed Sensors & Actuators Temperature (wing) … continued BIG BLUE II CDR University of Kentucky

  12. Deployed Sensors & Actuators Temperature (external & internal) • Sensor: TMP100 temp. sensor, “Texas Instr.” • Size: 0.12” x 0.067” x 0.037” (3 x 1.7 x 0.95mm) • Power Consumption: 45µA@3V • Range: -55º to 125ºC, ±1º , ±0.0625ºC resolution. • Interface: I2C Interface 40ms conversion rate, 25 conversions per second BIG BLUE II CDR University of Kentucky

  13. Deployed Sensors & Actuators Temperature … continued BIG BLUE II CDR University of Kentucky

  14. Deployed Sensors & Actuators Accelerometers • To collect scientific data, two accelerometers are used to measure the attitude of the aircraft (orientation of axes relative to the horizon) • Sensors: Analog Dev. ADXL202E and ADXL210 • Power Consumption: <0.6mA @ 3V • Operating Temperature: -40 to 85 °C • Range: -2 to 2g , -10 to 10g • Interface: Duty cycle using 1 PCA input per axis BIG BLUE II CDR University of Kentucky

  15. +3V 8 8051 ADXL202E 7 1 X channel Duty Cycle output Rset 6 T2 2 Xout 3 5 Yout 4 Y channel Duty Cycle output Deployed Sensors & Actuators Accelerometers … continued BIG BLUE II CDR University of Kentucky

  16. Deployed Sensors & Actuators High Current Switch • Part: IPS031 Power MOSFET from “International Rectifier” • Use: provide bursts of high current. For example, ballistic cutter, ATV cam, solenoid actuators etc. • Size: roughly 10 x 20 x 5 mm • Range: 12A, 18A bursts • Protected: shuts off if current>12A or if too hot • Features: low-current logic level inputs BIG BLUE II CDR University of Kentucky

  17. Deployed Sensors & Actuators High Current Switch … continued BIG BLUE II CDR University of Kentucky

  18. Ballistic Cutter Actuator Tantalum Cap scalable BIG BLUE II CDR University of Kentucky

  19. Ballistic Cutter Actuator Circuit BIG BLUE II CDR University of Kentucky

  20. Future Needs Any necessary sensor or actuator interface circuitry will be provided as needed. For example: • Parachute or wing-door deployment verification signals • Wing lift measurements BIG BLUE II CDR University of Kentucky

  21. Risks & Testing • Risks: • Sensor failure at low temperature/pressure • Interference & Errors can falsely trigger actuators • Low battery when deploying chute • Testing: Interactive during development and at launch site. Test functionality at low temp/pressure. BIG BLUE II CDR University of Kentucky

  22. Telemetry Objective: Develop data strings for communication with ground stations and for logging data into the black box during the flight. Team members: Aaron Welch Archana Vasudevan Dale Reid Chun Guan Matt Field BIG BLUE II CDR University of Kentucky

  23. Requirements • Provide high capacity local storage (black box) for telemetry data • Provide high bandwidth communication with ground • Develop reasonable coding scheme for telemetry data, possibly for each stage of flight BIG BLUE II CDR University of Kentucky

  24. Flash Memory • Used in 2 subsystems: 2MB black box and 8MB storage for camera • SPI interface • 3V compliant, so no regulation needed • Available in MMC packaging • Camera storage may be multiplexed chip selects to conserve I/O pins • Total I/O pins required: 4 on MC, 5 on camera (if multiplexing required) BIG BLUE II CDR University of Kentucky

  25. DataFlash Atmel AT45DCB004 8 MByte Capacity SPI Interface 2.7V - 3.6V Supply Flash Memory • Two SRAM Buffers • 13.2 mW Read Power • 5V Tolerant Inputs • Environment: -40 to 85C BIG BLUE II CDR University of Kentucky

  26. Multiplexing Flash Cards Serial In, Serial Out, and Serial Clock lines will all be common connections BIG BLUE II CDR University of Kentucky

  27. Telemetry String • Radios operate at 1200 baud • Data rate to ground: ~2 seconds • Black box data rate: variable • String length to ground: 64 bytes • String length to black box: 70 bytes • If sufficient rate available, pictures can be sent down as well BIG BLUE II CDR University of Kentucky

  28. Example Telemetry String Format • Bytes 1 to 28: GPS data. Includes time (hh:mm:ss), altitude, latitude, longitude, speed, track, and other data • Bytes 29 to 60: Sensor data • Bytes 61 and 62: Software tracking location • Byte 63: Health check bits • Byte 64: “/r” byte signaling end of string • Bytes 65 to 70: Sensor data only for logging BIG BLUE II CDR University of Kentucky

  29. Byte Breakdown of Sensors Byte 63: Health check • 29,30: airspeed (differential pressure sensor) • 31-34: altitude (absolute pressure sensor) • 35,36: yaw rate (gyro) • 37-42: 3-axis accelerometer • 43,44: compass • 45-48: wing pressure sensors (left and right) • 49,50: wing thermocouple • 51,52: tank pressure • 53,54: chute thermocouple • 55,56: internal temperature • 57,60: Mission length in seconds • Bit 0: Mission Control microprocessor • Bit 1: Autopilot microprocessor • Bit 2: Chute Control microprocessor • Bit 3: Camera health • Bit 4: ATV state (on/off) • Bit 5: Wing/Inflation state • Bit 6: Door state • Bit 7: open • 65,66: chip temperature • 67,68: external temperature • 69,70: UV intensity Logged Data only BIG BLUE II CDR University of Kentucky

  30. Ground Program • Used to decode telemetry string for easy reading in realtime • Gives the ability for much more complex encoding schemes BIG BLUE II CDR University of Kentucky

  31. Camera Sub-System • Objective Capture, process and store digital still images. • Requirements • 640x480 Pixel Resolution • Storage for 100 Pictures • Image Sensor Stable to -10C • Infinite Focal Length • High Level Interface BIG BLUE II CDR University of Kentucky

  32. Camera Sub-System Components Image Sensor JPEG Engine FLASH Storage 4 2 SPI RS-232 Camera Driver Data Bus Global Variables BIG BLUE II CDR University of Kentucky

  33. Camera Sub-System Components • Camera Module • Image Sensor • Omnivision OV7640 • Environment: -10 to 70C • 640 x 480 x 16bpp • JPEG Engine • Omnivision OV528 • Configurable Compression • Serial Data Transmission • Atmel DataFlash • AT45DCB008 • C8051F310 Processor • UART (Camera) • SPI (FLASH) • I2C (Data Bus) BIG BLUE II CDR University of Kentucky

  34. Camera Sub-System Verification • In chamber: temperature and pressure. • On test plane: vibration and shock. • On bench: file system and data processing. BIG BLUE II CDR University of Kentucky

  35. Parachute Control • Team Members • Garrett Chandler • David Jackson • Kevin Morris • Muthulakshmi Muthukumarasamy • Objective Deploy parachute to terminate mission as prescribed by the sequence or autonomously when failure modes are identified. • Srinivasa Patri • Osamah Rawashdeh • Dale Reid • Archana Vasudevan BIG BLUE II CDR University of Kentucky

  36. Parachute Control Integration Mission Control Flight Control Cut Actuator Accelerometers Airspeed Servos Wing Actuators Compass Rate Gyros Flash Memory Altimeter Accelerometers Video Actuators Pressures Radio Temperatures Data Bus Global Variables GPS Altimeter Chute Deploy CMOS - JPEG Flash Memory Chute Control Camera Driver BIG BLUE II CDR University of Kentucky

  37. Parachute Control Requirements • Deploy at Fixed Minimum Altitude • Deploy on Request from Mission Controller • Signal Fault Tolerant Firing Circuit • Automatically Identify and Respond to Error Conditions BIG BLUE II CDR University of Kentucky

  38. Parachute Control Components Altimeter 2 Chute Actuator 4 1 analog TTL Chute Control Data Bus Altimeter 1 Global Variables GPS BIG BLUE II CDR University of Kentucky

  39. Parachute Control Components • Processor • Silicon Labs 310 • Altimeter • All Sensors Corp. • 15 PSI-A-4V (104 kPa) • Chute Actuator • Holex 5800 Guillotine • TTL Logic Interface BIG BLUE II CDR University of Kentucky

  40. Parachute Control Failure Identification • Monitor Processors • Watchdog Counters in Global Variables • Reset Counters in Global Variables • Health Identifiers in Global Variables • Monitor Data Bus • Read/Write Tests to Global Variables • Monitor Power Bus • Backup Power Activated • Monitor Altitude • Minimum Set Point • High Rate of Decent BIG BLUE II CDR University of Kentucky

  41. Parachute Control Verification • In chamber: simulated decent. • On test plane: decent rate, min. altitude. • On bench: awash in radio EMI. BIG BLUE II CDR University of Kentucky

  42. Flight Testing • Flight Testing Team: • Andrew Simpson • Arvind Santhanakrishnan • Thomas Ritchie • Daniel Porter • Michiko Usui • Bobby Jones BIG BLUE II CDR University of Kentucky

  43. Flight Testing • Test fly individual pieces Test fly final configuration Preparation for Launch Flight Testing of individual components Flight Testing of Final Design Spring Break W/S March April Feb Feb 14 CDR May 5 Launch BIG BLUE II CDR University of Kentucky

  44. Flight Testing • Test fly final configuration • Varying altitudes • Varying conditions • Drop test at low altitude • Measure G-loads • Apply to high altitude John Herbst’s Hot Air Balloon BIG BLUE II CDR University of Kentucky

  45. Flight Testing • Obtain Lift and Drag for wing from wind tunnel • Test inviscid and viscous numerical models using CFD (TetrUSS) • Vary Re, Mach number, Alpha and Beta for final configuration BIG BLUE II CDR University of Kentucky

  46. Action Items BIG BLUE II CDR University of Kentucky

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