The DJI Matrice 100 is a quadcopter for developers. The drone allows developers to customize the flight platform using the DJI SDK. Today we assemble the Matrice airframe. Looky here:
Conceptually quadcopters are simple machines. There are four electric motors with propellers attached, each motor attached to the airframe, usually at the end of a boom. Each electric motor is attached to an Electronic Speed Ccontroller, or ESC. While there are a couple of variations in the way that these items are implemented (most notably brushed versus brushless electric motors, and the change in the ESC required to control them), at a high level the ESC is connected to a battery which provides the motor electricity, and the ESC is connected to a flight controller which controls the speed (and sometimes direction) of the motors.
On the quadcopter, two propellers turn clockwise, the other pair counter-clockwise. Each of the pairs are on opposite sides from each other. The flight controller (on the Matrice 100, the flight controller is a DJI N1) controls the speeds of each motor, which in turn determines the vehicle flight dynamics in three dimensions. These dimensions are known as roll, pitch and yaw.
In other words, the flight controller is a small computer which tells the quadcopter where to fly by controlling the motors. Typically a pilot communicates with the flight controller over a radio remote controller.
Over the last few years as flight controllers have become more capable, it has become possible for the flight controllers to implement more advanced behaviors and integrate different types of sensors which are typically used for navigation. For example, the Matrice has a GPS system which can be used to help plot different courses and geolocate the drone, and mark a know location as ‘home’ where the aircraft returns when requested.
Also, as in the case of the Matrice, embedded computers can be added to the platform which provide different levels of autonomy. The embedded computers can process sensor data and send flight control requests to the flight controller based on onboard algorithms. We tend to think of this as ‘flying robots’.
Building the Matrice Airframe
The Matrice 100 comes in several pieces. DJI provides instructions and a useful assembly video which was used during this build:
Assembly is straightforward, it’s mostly attaching bits and pieces from the development kit. Each of the screws has Loctite on it, which should help hold things together. The one tricky bit is attaching the antennas to the flight controller, this takes a little patience and finesse. It also helps to have small, nimble fingers. I just swore at it instead, and things seemed to have turned out ok in the end.