Components Developed for UAV Research

Every effort has been made to reduce the hardware complexity of these components. I designed most of them to work together in a variety of combinations. The software also provides considerable flexibility. Release of full construction and programming details is under consideration.

A overview of this flexibility, as it applies to the autopilots, is contained in 'An Unmanned Aerial Vehicle Autopilot'. The use of the name "Leveller" is a historical misnomer as the autopilots provide full attitude control and their functionality should not be confused with wing-levellers.

Autopilot (V3)

NavLev

Intersema Airspeed and Altitude

Intersema

Motorola Airspeed and Altitude

Motorola

Battery Monitor

BatteryMonitor

This was designed to be embedded within the primary motor battery packs. Unlike Laptop packs most aircraft do not have full condition monitoring built-in. The liability aspects make this an issue unlikely to continue. Currently sophistacted battery chargers are used, now with the increasing inclusion of cell balancing particularly for the more volatile battery chemistries (LiPo). Not commisioned.

 

Leveller (V2)

AutopilotV2

Originally used Microchip 16F876 and then upgraded to 18F2520; a far better option.

Navigator (V1)

Nav

Usually used in one of two configurations:

  1. Alone with relaying aircraft position by the telemetry link, or
  2. Exchanging mission planning information including target heading, altitude and airspeed to a Leveller (V2) while relaying navigation and leveller data.

 

Altera FPGA Autopilot Adapter

NIOS

This was designed as a daughter board to a general purpose Altera FPGA processor the latter normally running the NIOS soft-processor. The design was to support an FPGA based autopilot.

MaxStream Adapter

MaxStream

MaxStream R/C Adapter

MaxStreamRC

This is an extended version of the MaxStream Adapter that interfaces with JR (or other) RC Transmitters through a buddy box interface. The buddy box command stream is translated and packetised by RC channel before transmitting to the on-board autopilot. Only changed channels are transmitted to conserve bandwidth.

Groundstation (V2)

Designed as an inexpensive standalone pocket-size display of essential airframe and navigation data transmitted by our autopilots. Also acts as a de-packetiser for Micropilot autopilots. Outputs NMEA sentences for laptop display. To be replaced by a PDA based groundstation as the next development.

GroundstationV2

Groundstation (V1)

GroundstationV1

Single Port Smart Lead

Failsafe

General purpose TTL signal to TTL translator. Uses include:

  1. RC PPM signal integrity monitoring triggering an appropriate PWM signal to parachute or other flight termination device.
  2. RC receiver servo signal monitoring maintaining and transmitting counts periodically on a downlink for signals outside acceptable PPM specifications.
  3. Translation of RC PPM signals to camera commands.

VHF Link Packetiser and Beacon

Packetiser

The Radiometrix VHF transceivers require a preamble sequence to allow the data slicers to establish communications. The board may also be used as the Failsafe Beacon link pair. Version 1 of the packetiser was hand built board using an Microchip 18F876 with 2 TTL USART ports to transmit Micropilot telemetry oer a Radiometrix VHF link.

Dual Port Smart Lead

SmartLead

The Smart Lead can perform almost any combination of mixing and/or monitoring of up to two TTL inputs to create two TTL outputs. It is intended for shrinking inline into cables.

Examples of use include:

  1. monitoring Beacon signals and the Autopilot falisafe channel. If either fires then an output drives the parachute release servo.
  2. Translation of RC PPM signals to camera commands and switch closure for on/off.
  3. mixing a single PWM channel to two aileron servo PWM trains.

RS232C to TTL Translator

RS232C

Translates RS232C to TTL UART signalling levels. Intended for shrinking into a cable.

Altitude Alarm

AltitudeAlarm

Derived from Leveller (V2) as an altitude alarm for RC model aircraft. In use it pulses a camera flash and transmits an alarm tone to a simple groundstation when various altitude thresholds are reached. Developed at the request of the VARMS club who provided us with access to their flying field for our research. Ultimately spare Leveller (V2) boards were used.

Acknowledgement

I wish to thank Ray Cooper, Ian Reynolds and Paul Jenkins for their assistance in commissioning and, in some cases, improving these designs; team work.