Discussions

I'm a student in the UK, studying Electronic Engineering at university.

I've got a lot of experience with building and operating radio control models - boats, cars, planes and helicopters. As part of my degree, I have to make an electronics/programming project (taking roughly 400 hours).

I've decided that my project will be a quadrocopter stabilisation board, programmed and designed from scratch.  This board will be mounted on a quadrocopter, and should provide a very stable and agile flight platform.

The control board:
I plan to make a very sophisticated control board.  I will use GPS, ultrasound, and a barometer in addition to 3 axis magnetometers, gyros and accelerometers for an excellent awareness of the orientation and position.  The control loop will run very quickly (possibly around 300Hz+), probably running on an ARM7 or Cortex M3.

Software:
I will tune the quadrocopters PID loops using step response analysis, Matlab and Simulink.  Using this, I hope to get an exceptionally stable system.

The Quadrocopter:
The actual frame and physical build of the quadrocopter is not part of the assessed project.  It is purely a base to use and test the control board on.  While I have a lot of background knowledge in rc stuff such as brushless motors, I'd love to have some input from you more experienced people on what good component choices are.

The Frame:
Obviously one of the most important parts of the quad.  While I have a workshop with a CNC machine as well as carbon fibre moulding equipment, I came across the Turnigy Talon V2 while searching, and it looks ideal for my needs.  I may cut the arms down a small amount for a 45cm-50cm motor distance.  This quad looks very solid and crash resistant, as well as able to handle a lot of power and fast motor responses.

Propellers:
EP1045 (10"x4.5") seem to be some of the most commonly used propellers for quads - these seem a good choice for their low cost and easy of availability.

Motors:
The way I see it, you can't really have too much power.  I hope to have very fast levelling and manoeuvring capability, which means a high peak power.  The ability to carry a moderate camera if desired is also good.  I would really appreciate any input regarding motor choice - and hopefully one that can be top mounted to the frame, which looks very neat.

A quick search of hobbyking revealed this 1050kv 225w(ish) motor - would four of these make a suitable choice?

Edit: My latest thought is to use E-Max GT2215/12 motors - although not really rated for 4s, I'd imagine I would rarely need to use them past 50% throttle or so in normal flight.

ECSs:
As I mentioned, I want my quad to have very fast responses in able to stay very stable.  This certainly rules out commercial ESCs without reflashing them.  However, I am unsure how capable commercial ESCs become once reflashed - I really want the ability to have very short bursts of high thrust for stabilisation.  I'm currently siding towards an ESC specifically designed for quadrocopters - such as the MikroKopter design. In addition, I2C is preferable to regular PPM.

Batteries:
For a long flight time, I'm planning to use either 3s 5000mah or 4s 4000mah packs. Some of my high performance boats use two 2s 40c 4000mah packs (in series), so using that same format would make some sense as I already have those.

Other bits and pieces:
I think I'm okay for all the other bits and pieces I'll need (eg wire, connectors etc).  I own a Futaba 6EX for my helicopters, and I'll build low voltage alerts into my circuitry for the lipos.

Any thoughts or comments are most welcome - especially on motor and ESC selection! This youtube video shows the sort of performance I'm hoping for - very sharp responses with little or no oscillation.

Cheers,

Andrew