I was able to (finally) get the Drone into the air last week and it went very well!
The control system successfully stabilised the plane and directed it towards the desired waypoints.
The flight time was cut short at around 11 minutes due to rain however this short flight has demonstrated the core capabilities of the control system.
Lots of progress since the last update.
- The Ground Station is now mostly working.
- The FPGA based autopilot is now at a stage where it is ready for gain tuning, ground testing and semi autonomous flight.
- Interface electronics has been debugged and is almost complete.
I put the drone in the back of the car and took it for a ride around the block. Everything seems to be working which is fantastic!
Screen shot of the ground station, there seems to be some discrepancy between what the GPS is telling me and the location shown Google Earth. I am fairly confident that the GPS is reading correctly so I have a feeling that this could be an inaccuracy in Google Earth (more investigation needed though).
Mounted autopilot, the bottom board is the NI-sbRIO 9606 and the top board is the custom interface daughter card that has:
- Four RS232 ports
- Four I2C
- Eight 12 Bit A to D converters
- 10 PWM in
- 10 PWM out (with high current 6V rail)
- Dual redundant power supply inputs
- Digi 9Xtend 1W RF modem
- 5 High current relay outputs
- 25 General 5V IO
The old bottle drop mechanism was fairly dodgy so I have re-vamped it.
This is tricker than it looks as the water bottle weighs greater than 500g which is a significant part of the aircrafts weight and mounting such a mass directly over the center of gravity difficult.
I wanted the simplest mechanism possible to hopefully avoid breakdowns so I went for a single lock-pin design see pictures below.
So far I have been working on the general architecture of the ground station as well as some Google Earth functionality.
The ground station's architecture is centered around "missions", a mission is a collection of information pertaining to a single flight.
A mission currently contains the following information.
- Flight initialisation information (i.e. where do you want to start from).
- Flight waypoints.
- Mission Boundaries.
- Points of interest.
- Recorded flight data (recorded path, speed etc).
The following series of screen shots shows the flow of the ground station program from initialisation to main interface.
Microstrain have provided discounted pricing on a 3DM-GX-45 GPS aided inertial navigation system for use in the 2011/12 Outback UAV challenge.
Key features of the 3DM-GX3-45:
- Fuses data from GPS and AHRS to provide single optimal navigation solution.
- RS232 or USB interface (I went for RS232).
- Can compensate very well for GPS outages of 30 seconds.
- Tiny size (24mm x 44mm)
Single Board RIO 9606
National Instruments is providing Rescue Robotics with a sbRIO-9606 embedded computer & software for the 2011/12 Outback UAV Challenge.
The main features of the 9606:
- 400 MHz processor with real time OS.
- 512 MB nonvolatile storage, 256 MB DRAM.
- Xilinx Spartan-6 LX45 FPGA.
- 96 3.3 V configurable DIO lines.
- Mezzanine connector to interface FPGA with custom daughter board.
- 10.3cm x 9.65cm dimensions.
- Can be fully programmed in LabVIEW
More on product page here: http://sine.ni.com/nips/cds/view/p/lang/en/nid/210003