Here is a short video showing my quad just after using the APM Autotune mode to automatically set the PID feedback values for the autopilot. I must say it did a wonderful job, albeit a it resulted in a fairly aggressive tuning. This is in contrast to the initial tuning with Qground control, the PX4 branch, which does not yet have an auto tune feature. Instead it uses an iterative process starting with holding the actual copter in your hand while PID tuning. Mind you, I wore my leather jacket and chaps along with my full face helmet while spinning the copter up to hovering power while holding it in my hand. I do hope that you realize that that these copters are little more than Cuisinarts with carbon fiber blades. 😮
Towards the end of the video you will notice that the low battery warning occurred and the autopilot entered into the RTL Return To Land mode. I tried to bring the beast down by manually overriding the RTL with the throttle but it would not respond to my commands. That is until I switched back to Stabilized (manual) mode and awe shite! The throttle was near minimum and the damn thing dropped like a rock. I had the default settings with the left most switch controlling the flight modes which means that my thumb was off of the throttle – HUGE F-ING MISTAKE! As you can see just how quickly things can turn to shite, especially when so close to the ground.
Here are the results, one broken prop, one broken landing gear dowel, and one broken quick release prop adapter, which actually saved the prop it was attached to. I’m looking into using fiberglass rods, with pads at the ground contact area, positioned at about a 60 degree cant for shock absorption rather than the 90 degree positioning in this prototype set up.
This is sooooooo freaking much fun I can’t possibly tell you. I love engineering and product testing. I don’t mind spending resources on learning experiences but I do take exception with being taken for a rube by nefarious marketing and sales practices. On the other hand DJI does actually have some decent concepts that it is putting into practice, mixed emotions.