Designed by a team of five electrical and two computer engineering students for the SDSU senior design competition, V.A.D.R. is an autonomous delivery drone designed to deliver a payload to different GPS locations. The drone uses a PIXHAWK micro-controller to control all of the drones components, and also to control the fully autonomous mission. The drone will compete in a competition to fly to three GPS coordinates, release a marble on each location, return home and land safely. Update: We were very successful during the challenge, getting an accuracy on average of 2 feet per target and we took home 1st place out of the three teams.
The software we used for this project is called Mission Planner. Mission Planner is a massive program for do it yourself drones. It had everything we needed to get our custom drone and its components calibrated to fly stable. It also has a section to program different waypoints and set up servo commands. We used that section of the program to carry out our payload delivery challenge.
Here is the main screen of mission planner. It displays important flight data as well as a live map view of where the drone is located using GPS. We are able to get these readings through the wireless connection between the drone and the computer using the telemetry module.
Next we will go through the process of setting up mission planner to get our drone to work. The first thing that needed to be done was choosing the frame type.
Then we needed to calibrate the accelerometer built into the pixhawk flight controller. We clicked on the top button and it directed us to do place the drone level, the on its left side, right side, nose down, nose up, and finally on its back. Once we did these positions the accelerometer was calibrated.
Next we needed to calibrate the compass. This was the most vital step in the setup and we had to make sure we got this perfect. It is important because the compass is used for the autonomous flight and a calibration that was slightly off can produce a drastic error in the route and location the drone flies to. We clicked on live calibration and had to rotate the drone in a circle around all axes.
Then we calibrated the radio transmitter (Turnigy 9x). We hooked up the transmitter to the drone using the reciever and ppm module. Once we were able to get a connection we went into this radio calibration screen. We had to move all controls to its maximum and minimum limits and the software took readings.
Next we tested the motors to make sure they were all working well and were in the correct position. Each motor of the drone needs to be plugged in the correct sequence on the pixhawk to ensure they are in the correct position. Motor A is the top left, motor B is the bottom left, motor C is the bottom right, and finally motor D is the top right.
Then we did some fine tuning to get the drone to turn sideways and forward at a speed we specified. We also set the takeoff speed to the lowest amount so it was a softer take off and easier to do.
Once we had all the components calibrated and set up, we went into the advanced parameters page. Here we can change a ton of things such as maximum altitude at which the drone reaches during the mission and horizontal speed during the mission.
Next we set up the mission. On this screen we can set up waypoints the drone will fly to during the mission. These waypoints will be the locations we are to deliver the payload. A waypoint is just a GPS coordinate. The drone will take off, reach an altitude specified in the parameters, and then head to each waypoint in order. Once it reaches the final waypoint it till return to launch. These waypoints in this picture are the ones used in the autonomous demonstration videos below.
Finally we need to set up flight modes. On takeoff it starts off in stabilize mode which is just regular RC control. We programmed it so once we flick a switch on the RC it will enter flight mode 6. We set flight mode 6 to auto. Auto is the mission, so once we flick the switch the drone will carry out the mission.