Difference between *maker* and *engineer* obvious in that one...
Difference between a Marketing driven Company built on BS Hype and an Engineering based approach.
Adafruit vs Boston dynamics
Hoo boy... there are so many examples of wrong in that UAV I really don't know where to begin. A lot of the hardware I can see is clearly hobbyist-grade parts intended for use on mini & micro racing quadcopters, with no consideration of the exponential increase of the dangers involved in "super-sizing it".
The failsafe as described is almost a "failure guarantee". At one point they stated the relay would kill power to the FC, resulting in no signal to the ESCs which is a huge no-no... in the event of loss of radio signal, failsafe loops should either attempt to level the craft and slowly descend, or at least kill the craft completely by pulling the ESC signal pins LO and holding them there as long as there is power to the ESCs, which clearly was not implemented in their "custom firmware".
This is why all the popular hobbyist-grade firmwares, while admittedly open-source and written by volunteers, still have multiple avenues of failsafe implementation in the firmware depending on the primary purpose of the copter. To not take advantage of that as seen here is, IMO, criminally negligent.The nature of these things makes a relay in the main power nearly impossible to implement, for the same reason a fuse doesn't work. The only viable emergency kill switch is going to be either something that cuts the main battery wire physically, or something that forces the main power connector apart. The latter has been tried, and unfortunately does not always work due to the connectors' tendency to weld shut when moved under high current load.
The problem here, I think... is that the builder was trying to bring the high-angle-of-attack fast-forward-flight performance and responsiveness of our tiny racing quadcopters to this experimental prototype of something almost human-sized. This is pretty much the exact opposite design scope as multirotor craft which are actually designed for flight around people; ie cinematography rigs, inspection drones and firefighting drones. Those are designed for maximum level-flight stability and redundant flight control such that operator control is never lost, or if it is, the UAV lands itself autonomously in a controlled fashion.
I could write aboot what I can see wrong with this thing for hours... but the fact is, most of what is wrong with it is also what is wrong with the mini & micro quadcopter hobby as a whole; only they applied that wrongness to a craft that is exponentially more dangerous due to its size.
Even the little acro ones I like to fly are capable of seriously hurting a person if it comes into contact with soft fleshy bits; they are little flying blenders with four 0.5-1.5HP motors spinning knife blades at 20k-120K RPM. This does not even address the kinetic energy that a 500-800 gram craft can impart if it were to fall uncontrolled from a great height, which any of them can reach if the ESCs just ramp up and stay at WOT.
There's a reason I drifted away from the hobby in general after the FAA jumped all up our butts due to the epidemic of DJI Phantom-flying bozos who kept flying over people and posting videos of their stupidity on boobToob... It's because I realized that with very few exceptions, these things... all of them... planks, helis, quadcopters and drones... are fucking dangerous as all hell, and they're only going to get more dangerous the more crowded this planet becomes and the more people want to play with them and show off their skillzz and shiny new toyyzz.
mnem