Kelly Robotics

I’ve decided to build an RC Quadcopter.  I’ve currently got an AR Drone 1.0, Nano QX and a 1SQ V-CAM.  The new one is going to be built from parts rather than an ‘Ready to Fly’ or ‘Almost Ready to Fly’ (RTF or ARF).

There are four major components to the quadcopter:

1. Frame
2. Power Plant
3. Flight Control System
4. Transmitter/Receiver

Frame:

Quadcopter is a class of Multi-Rotor Copters; they can can three, four, six or even eight motors!  Quadcopters offer a good balance of lift capability and cost.  Hex and Octo-copters give more stability and failure control, however, they are more expensive.  Tri-Copters are less expensive, but less stable and have less lift capability.

I’ll be building a Quad-Copter.  The frame I chose is a HobbyKing X650F Glass Fiber Frame.  Looks nice and strong, has plenty of room to mount the Flight Control System and has a camera mount.  Built out it will 550mm (~21 inches) wide.  I think the key for a frame is that it be level and rigid; the motors all need to be at the same level and mounted square to the ground and parallel to each other.

Power Plant:

When I placed the order I pretty much just took a shot in the dark with respects to the motors and props.  With the power system you have the battery, motors, electronic speed controllers (ESC), propellers and wiring harness.  Not sure how mine will turn out; I took a shot in the dark with respect to the motor sizes and I got two sizes of props (. x 4.7 and 10 x 4.5)  The motors are 28-26 NTM motors at 1000 KV (RPMs/v); that might be a tad fast.  We’ll have to see how it works.  I’ve got 3000mAH battery for it and I’m expecting somewhere around 7 min flight times.  Finally, everything needs to be wired up.  There is a power distribution harness that splits the power from the battery to the four ESCs and then to Flight Control System.  The trickiest part here is matching up all the connectors on all the parts; but that has always been an issue with electrics RC stuff.

Flight Control System:

I’m using a HobbyKing “MultiWii and MegaPirate All-In-One Pro” flight computer.  It is basically an Arduino Mega 2560 w/ an Accelerometer, gyroscope, barometer and magnaometer, I2C port, FTDI port, and 2 serial ports.  It can use MultiWii or MegaPirate software packages for handling all the inputs (receiver and sensors) and setting the motor speeds.  I decided to start with MultiWii; just because it was the first one I came across.

MultiWii can be downloaded from http://code.google.com/p/multiwii/

MegaPirate can be downloaded from http://code.google.com/p/megapirateng/

Transmitter/Receiver:

I’m using a Spektrum DX6I 6 channel transmitter and I paired it with a very inexpensive Orange DSM2 receiver.  The transmitter for quadcopters are normally setup in ‘Acro’ mode.  This is because the ‘Heli’ mode does the mixing of the channels in the transmitter, but the Flight Computer does the mixing for quadcopters.  So, we don’t typically want to do much mixing in the transmitter.