Sometimes a flight experiment gone awry exposes a set of behaviors that directly correlate to previous design choices. It's a moment of validation based on developing systems with the expectation that they will fail. The video below is an example of one of these moments.
During one my daily experiments with multiple robots, one of aircraft experienced a GPS interference event on takeoff. It skirted across the ground and flipped over, the motors still spinning. Often, I will lower the throttles and shutdown the experiment. On this day, however, I made the decision to let the two well behaved robots fly and see if I could "rescue" the flipped aircraft.
NOTE: I do not condone approaching an aircraft and interacting with one while motors are active. That being said, I broke my rule on this occasion. I'm fully aware of the multitudes of outcomes that could have arisen. Being familiar with this set of aircraft over the last 6 months, I took a calculated risk. That being said don't interact with an aircraft when propellers are spinning.
As mentioned in the note, I approached the aircraft looked at the motors and props and noted no damage. The aircraft had flipped and was still trying to fly to its hover point. At this point, I could have shut down the aircraft but I didn't. I picked it up by the battery aware that aircraft will have torque and try to continue it's flight. As I lifted it, I could feel it wanted to fly to it's hover point. I checked the GPS status of the aircraft and, once again took a calculated risk, letting it go with the expectation that it will fly to its hover point. As the video below shows, it did complete its mission. What I didn't observe at the time, was that I was holding the aircraft 180 degrees off its orientation. So when I released the robot , it did it's best to "right" itself and fly to its hover point. Not until I reviewed the flight log and video did I understand why it performed the way it did. In my mind it should have just flown up but I hadn't detected that I was holding it backwards when I released it.
It should be noted that there are redundant radios and safety systems in place to manage these aircraft. The only person I put in harms way was myself. I've been flying these systems for the past six months and they have been tested multiple times where flights don't go as expected. As a matter of fact, I plan for failure and relish the uneventful flights where everything goes as planned.
The upside is that the robot survived a less than optimal takeoff and completed it's mission with a little help from a friend.
Upward and Onward!
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