Thursday, 12 March 2015

Multicopter. (Part 9) Starting the third phase

Things have been quiet on the multicopter front owing to too much work and not enough good weather. What I did go flying I ended in a crash which broke 2 of the 4 Quadcopter arms. I decided, as the 3D printer churned out the replacement arms, that I would move straight on to my phase 3, as defined in previous posts, which is all about the APM flight controller. 

I bought a cheap 'cloned' hardware kit from Hobby King and started putting it together.

This kit comprises the following:
  • The  APM flight controller board and case. 
  • A circuit board that monitors the battery voltage and current used by the motors, and provides a stabilised power supply to the flight control board. 
  • An OSD circuit board. This overlays video from the existing camera with data from the flight control board. It then supplies a composite picture, camera view and data view to the video transmitter.
  • A pair of 433Mhz wireless modems, one which connects to the data port on the flight controller and one to connect to a laptop, tablet or smartphone
  • A GPS and magnetic compass sensor which provides position and heading information to the flight controller card.
  • All cables, cases and fittings.
This was all was excellent value at 180 euros and cheaper than the 3D robotics price. (more than 340 euros) Of course, 3D robotics and the open source community have done all the engineering. And for all I know the Chinese manufacturer of these clones is using exactly the same tooling and engineering information as are used in 3D robotics original parts. 3D Robotics APM . The firmware, latest versions, downloads to the cloned flight control board and the wireless modems from the 3D robotics site.

I also downloaded the 'mission planner' software. Which turns a laptop, an Android tablet or a smartphone into a mission planning control tool for the quadcopter when its finally assembled.

But I need to recap. 
Phase 1. The Quadcopter is firstly controlled by my 2.4Gb radio control transmitter, this was all that was possible at Phase 1.

Phase 2 added the video camera and video transmitter which offers the option of direct control but now by referencing the 'pilot's eye view' from the onboard camera. 

Phase 3 replaces the earlier KK2 board with the APM controller board and the additional features shown above. This gives a machine which can also fly a pre-planned route, beyond direct line of sight range, and with some autonomy. It may also be flown from the ground but through a variety of selectable modes which use the onboard navigation information has a reference.

After much application of tie wraps and double sided tape the new configuration is nearly ready and will soon be available for a test flight.

No comments:

Post a Comment