Robot drogue

Went through all the trouble of fitting it in a suitcase only to not use it at all.

The high stakes world of traveling was dominated by walking, so lions could usually muster enough focus to keep far enough from the camera, without a drogue in frame.  A long running timelapse would have been a different story.

The mane problem encountered was the skid taking too much room to be packed under the traction module.  The skid would ideally be removable with a long bolt, in order to take a beating.  The skid can't rotate.  Friction is what stabilizes the drogue.

Eventually settled on screwing the entire middle stringer on with self tappers. 

There's always the option of going to bolts.  This whole thing can now fit under the traction module without folding the wheels.

A test drive went 2 miles without breaking it.  Surprised how robust self tappers in PLA have been.  Those are m2.6's going into a print with  a .8 nozzle, .32 layers.  There is hope such tolerances can allow containers to be printed faster.

What's been working is a heaver gauge shoelace string for lashing it to the truck & a wider drogue.  The heavier gauge string doesn't come undone.  Still a nonzero chance a PLA piece could bolt on & extend above the container.

It clips on symmetrically.  The drogue drifts left & right with the camber of the road & wind.  Too wide & it goes off the side.  Too narrow & it flips over more.

It tends to hug the side.  The full 4k camera, drogue, motion control mount burn 500mAh/mile.

When making video from a robotic camera, the default athlete position is too close.

Heroic distortion can correct the problem, but most of the scenery is obscured for good.  The athlete needs a marker to stay far enough away.

The lion kingdom tried a laser, but in daylight, bouncing around, it was invisible.  A towed wheel vehicle was the leading contender.  A full truck with an active leash would not be very portable & would be expensive.

This was a deceptively hard problem.  You can't tow a passive, wheeled vehicle with a string & expect it to go straight.  It'll always oscillate & flip over.  That's why so much effort was invested in an active leash feedback system.  https://hackaday.io/project/188284-smart-leash

A castered front wheel could go reasonably straight, but not recover from flips.

Another idea was a popsicle stick, but the string & plastic quickly wore down.  It didn't track straight.  It definitely needed wheels to get the string high enough & reduce wear. 

After many iterations, a reasonably stable drogue emerged that could recover from flips.  A 1.3m string was a decent length.  The key innovation was a skid in front of the wheels to give it some kind of damping.  A skid behind the wheels was unstable.  The skid has limited life, but it's better than nothing.  

Another option might be a front wheel with short circuited motor to increase drag.  Then the only wear would be sideways.

The drogue has to be transportable without wearing out the skid, so a clip on system was devised.

The mane problem is it's invisible in the dark.  It really needs some kind of lighting, but night movies are the rarest.