Background

The field of Unmanned Rotary-Wing air vehicles holds great promise for accomplishing a wide range of exciting commercial and military missions.  There is a need for a variety of on-board sensors to enhance the situational awareness, assist ground-based pilots, or measure the "health" of the aircraft.  Many recent advances in miniaturization of sensors, computer processors, power supplies, and data storage hardware can be incorporated into radio controlled model helicopter systems.

  Design Objective

The objective of this project is to design and implement an on-board data storage system to record fuselage vibrations and noise levels during radio controlled helicopter flight testing.  

The system will be able to be started and stopped from the ground and will collect 5 or 6 data sets of 10 seconds each.  

The system must be lightweight in so it does not affect the flight of the helicopter.

The system must be able to synchronize the data collected and a video of the helicopter flight.

The system must be able to measure and record vibration signals onboard the helicopter when the helicopter is in a maneuver.

The system must not interfere with any part of the helicopter’s operations.

  Solution

For our solution, we first chose an accelerometer to collect the vibration data.  This data then goes through a low pass filter to remove any extraneous high frequencies.  The analog data then is sent to the microprocessor board which contains a built-in analog-to-digital converter.  The board stores the digital data in it's own memory.  Later this information can be read through the serial port to an on-ground pc for decoding.. 

The system can be started and stopped through the radio transmitter used for flying the remote control helicopter.  The signal is received as an interrupt to the microprocessor which starts a routine to either start or stop collecting data.  The processor contains more than enough memory to store the data from the flight routines.

The data collected is synchronized with a video of the helicopter by starting the video at the same time that the data collection is started and then combining the two afterwards.  The goal is to have a video of the helicopter with the vibration waveform superimposed on it.

The entire on-board system is run by a 7.2 V battery which then passes through a voltage regulator to keep it at 5 V.  The battery is sufficient enough to run twice as long as the expected sampling times.    

The board, battery, and other circuitry is very lightweight and again more than meets the design constraints of being less than 10 lbs. 

 Links to system components