Autonomous Helicopter

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Autonomous Helicopter
James Lyden EE 496 Harris Okazaki
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Project Overview

• The goal of this project is to create a
  helicopter capable of flying itself. The
  helicopter should be able to take off, fly to a
  predetermined location, and land without user
  input (during flight). The target will be
  specified pre-flight by a user, through a
  computer interface.

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Hardware Modules

• Onboard Controls
• Master Microcontroller
• Slave Microcontroller
• Sensors
• Accelerometer
• Gyroscope
• Communications
• Bluetooth Transceivers onboard and on PC
• PID Correction System
• PC

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Block Diagram
OFFBOARD
ONBOARD
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Software Flow
PC Software Flow
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Software Flow
Master µC Software Flow
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Software Flow
Slave µC Software Flow
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Focus Accelerometer Interface (components)?

• Digital Interface
• Microcontroller I²C Master
• Accelerometer I²C Slave
• ADC performed by accelerometer
• All data transfer performed via register
  read/write
• Wiring
• SCL clock, synchronizes data rate
• SDA Bidirectional data line only one device can
  transmit at a time, negotiated by I²C protocol

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Focus Accelerometer Interface (tests)?

• Communications test
• Read the WHO_AM_I register, verify it reports
  known value
• Write config data to CTRL_REG1, read to verify it
  worked
• Scale test (once per axis)
• Tilt sensor so target axis is subject to gravity,
  read the value of each axis, verify target axis
  is roughly 1g while other axes are roughly zero.
• Speed test
• Read values from all 3 axes at a rate of 2.56KHz
  (delay 390 µs between reads), ensure data changes
  as we tilt sensor

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Focus Accelerometer Interface
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Focus Accelerometer Interface (design decisions)?

• Using digital vs. analog interface
• Analog interface would have required using
  microcontroller's ADC, which would also be
  occupied by gyroscope
• Analog interface used 3.3V logic, limiting the
  full range when coupled to the 5V microcontroller
  ADC
• Less ADC code interspersed through the
  microcontroller code
• Using I²C vs. SPI
• SPI uses 4 wires, where I²C only requires 2
• Using one 3-axis device vs. multiple single-axis
  devices
• Size and weight constraints, as well as wiring
  complexity

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Remaining Work

• Testing
• Gyroscope digital interface
• Master microcontroller loop speed
• We need to know if the loop runs faster than ADC
• Refinement
• PID scale tuning
• Optimize code in master microcontroller main loop
• If we have time, increase baud rate for serial
  communications
• Implementation
• Accelerometer interface (partially done)?
• User interface

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Gantt Chart