inertial measurement unit “imu” (analog devices adis16350)

Inertial Measurement Unit “IMU”

(Analog Devices ADIS16350)

- Tri-axis gyroscope ± 75°/s, ± 150°/s, ± 300°/s settings - Tri-axis accelerometer ± 10 g measurement range - 350 Hz bandwidth - Dimensions: 23 mm x 23 mm x 23 mm Microcontroller (AT91SAM7S256)

- Flash, 64K Bytes RAM, USB 2.0, RTT, 10 bit ADC 384 ksps

- 2x UARTs, TWI (I2C), SPI, 3x 32bit TIMERS, 4x PWM, SSC, WDT

- PDC (DMA) for all peripherals, up to 60MHz operation

- Dimensions: 80 mm x 120 mmGPS (San Jose Navigation)

- Refresh rate: 5 Hz- Accuracy: 3.3 m accuracy, 2.6 m accuracy with DGPS- Dimensions: 2.6 cm x 2.6 cm x 0.6 cmAirspeed (Eagle Tree Airspeed Micro Sensor)

- Range: 2 MPH to 350 MPH ± 1 MPH- Weight: 7 Grams- Dimensions: 28 mm x 16 mm x 10 mmAltimeter (Zlog)

- Range: 0 to 10000 ft ± 1 ft- Weight: 8 Grams- Dimensions: 40 mm x 23.4 mm x 9.4 mmMeasurement Box Design- Mounting positions for all sensors & includes vibration isolation- Dimension: 3 in x 3.25 in x 3.75 in w/t base plate 6 inPitot Tube Mounting Design- Allows for quick sensor removal and

replacement- Dimension: Contained between

outermost 2 wing tip ribsUltrasonic Sensor (Maxbotix LV-EZ0)

- Range: 0 to 255 inches- Dimensions: 21.1 mm x 19.9 mm x 16.4 mm

Project Background:The long term goal of this project is to create, field and implement a full system of measurement devices that will be used to control an unmanned aerial vehicle. This will be the first quarter that the project is being worked on, and the primary goal will be to implement off the shelf measurement devices to characterize the necessary parameters for in-flight control of an unmanned aerial vehicle.

Problem Statement:The project will combine several sensors to measure the fundamental parameters of in-flight movement to allow for a flight control system to calculated the necessary information to sustain flight.

Objectives/Scope:- Measure real time position of test platform- Measure real time flight parameters- Ensure measurements are

accurate and reliable

Visit our wed page for more information and documentation:https://edge.rit.edu/content/P09233/public/Home

AIRFRAME MEASUREMENTS GROUPMEASUREMENTS BOX

Group MembersMichael Skube (ME), James Hunt (ME), Joseph Peters

(EE), Bill Atkinson (ME), John Isely (ME), Heidi Morgan (EE), Kevin Li (EE)

Faculty Advisor: Dr Jason Kolodziej

P092332008-3

& 4

Eagle Tree Velocity Sensor

GPS Zlog Altitude Sensor

Microcontroller Ultrasonic Altitude Sensor

The altimeters where tested against a calibrated pressure sensor to show their accuracy, based on repeatability and accuracy, the ZLOG altimeter was chosen.

GPS data was collected on a drive around the outer loop of RIT to shows it’s accuracy.

The completed measurements box fits inside the fuselage of Airframe A (P09231). The box is attached with 4 thumb screws, and the complete box also acts as the outer fuselage, sealing the hole that is required to insert the box into the airframe.

IMUInertia Measurement Unit

Pitot Static Tube Mounting

Complete Measurements “BOX”

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Data Collection Event

Pitot Static Tube vs. Anemometer (Automobile Test)

Airspeed SensorAnamometer

The Pitot Static Tube was compared against a anemometer, measuring the velocity of a automobile, the accuracy is reasonable given the low cost of the Pitot Static tube setup.

Box inside Airframe A

Measurement Box in Airframe A

and sensor mounted in the wing tip, both can be removed and replaced without complete wing disassembly.

Velocity Sensor

Pitot Tube

Pitot Tube Mount

Sensor and MCU Integration

Special Thanks to

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Vacuum Chamber Simulated Altitudes

Zlog

Eagle Tree

Pressure Sensor

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Vacuum Chamber Simulated Altitudes

Zlog

Eagle Tree

Pressure Sensor

MCU

BEC

PCGPS

Pitot Static Tube

Altimeter

IMU

JTAG

Altimeter Control

GPS Control

IMU Control

Serial

Serial

SPI

ADC

14.4V 5V

5V

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5V

Additional Electronics

Initialize MCU Peripherals.

SPI Initialized.UART0 and

UART1 Initialized.

Several Peripherals are used to interface the Microcontroller with the sensors. The GPS and Altimeter are interfaced with the 2 UARTS. The IMU and SD card are interfaced with the

SPI.

Initialize timers and setup

interrupt service routines.

The timers and ISRs are used to control the recording rate of the sensors.

Initialize the GPS.

GPSCommands are sent through the UART to control the GPS. The GPS utilizes NMEA protocol. Several types of data can

be obtained from the GPS in addition to position.

AltimeterAn ASCII ‘L’ is sent through the UART to toggle the state of the Altimeter between on and off.

Initialize the SD Card.

SD CardCommands are sent through the SPI in a 6 Byte packet

which consist of a command, data and checksums. 74 Clock pulses on the SPI along with a Logic high on the MOSI and

chip select lines places the SD Card in SPI mode.

IMUThe IMU consists of 6 sensors. The SPI is configured to send 2 byte length commands. The MCU controls which

sensor data is places on the MISO.

Continuously Read GPS, Altimeter and IMU. Calculate speed, relative position and

heading from IMU.

Has timer reached 0.

Record Data from sensors to SD Card.

Yes

No

Enter while loop forever.

Initialize the Altimeter.

Initialize the IMU.