Smooth paths, splines or many waypoints

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#1
In Tower or MP, what's the best way to get smooth flight paths along random curves? I'm finding it difficult to impossible to replicate specific curves using spline waypoints. There's a small river I'd love to fly down, but there are random curves and straight sections that seem to thwart any attempt to lay a flight path right down the center.

At the same time, my flights using straight waypoints seem pretty smooth - the quad does a nice fly through the corners as opposed to stopping, rotating towards the next waypoint and continuing. I think in the flight controller's parameters I have a 5 foot radius set, so as long as the quad gets within 5 feet of the waypoint, it checks it off it's list and continues to the next.

So that makes me think it'd be better to use a bunch of normal waypoints than a few splines. I'm going to test this over the next few days, but I thought I'd ask if anyone else has run into this.
 
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#4
I've wanted the same feature for my P3P where it smooths out corners into curves but I bet they wont add it since at that point you are asking it to fly NOT on the predefined path but figure out a nice curve and this is where it could potentially clip something on the inside of the turn if it's too tight.

I think the best option is to just add more waypoints.
 
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#5
So I've been experimenting with this, and it seems to smooth out waypoints automatically. I've been flying my 250 along waypoint paths and then downloading the logs to overlay the actual flight path. Here's a pic of the actual path is flew when given a 5 waypoint curve.



Pretty smooth. From what I've read, the way the Pixhawk works is that it chases an imaginary point out ahead, which itself does follow straight lines between waypoints, effectively smoothing out the path. That does mean that in tight turns, it can miss the actual location of a waypoint by some distance under certain circumstances. In my example, this was a pretty symmetrical curve, but I was flying into it at probably 35 mph, so it looks like it may extend the imaginary chase point further out the faster you're flying.

If, like me, someone wants to set up a very specific path, waypoints seem like they'll do the job, but you'd definitely want to fly it well above any obstructions, download the logs and verify that the path it actually flies wouldn't clip anything. My goal is to fly down a mile or so length of a windy river, well below the tree line. It'll take some more experimenting, but this seems like a good workflow - waypoint path, fly it above obstructions, verify the logs, then lower the altitude.
 
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#6
Both informative... AND totally cool! Thank you for posting. I haven't had enough time this week to experiment with tower so I love that I can log on here and see someone else getting great results!
 
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#7
So I've been experimenting with this, and it seems to smooth out waypoints automatically. I've been flying my 250 along waypoint paths and then downloading the logs to overlay the actual flight path. Here's a pic of the actual path is flew when given a 5 waypoint curve.



Pretty smooth. From what I've read, the way the Pixhawk works is that it chases an imaginary point out ahead, which itself does follow straight lines between waypoints, effectively smoothing out the path. That does mean that in tight turns, it can miss the actual location of a waypoint by some distance under certain circumstances. In my example, this was a pretty symmetrical curve, but I was flying into it at probably 35 mph, so it looks like it may extend the imaginary chase point further out the faster you're flying.

If, like me, someone wants to set up a very specific path, waypoints seem like they'll do the job, but you'd definitely want to fly it well above any obstructions, download the logs and verify that the path it actually flies wouldn't clip anything. My goal is to fly down a mile or so length of a windy river, well below the tree line. It'll take some more experimenting, but this seems like a good workflow - waypoint path, fly it above obstructions, verify the logs, then lower the altitude.
@rrmccabe has a very cool video he did with his white one that showed that exact type of path. It was a very neat video that you would enjoy, even if it was done with a different quad. Perhaps we could get him to post it here?
 
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#8
Perhaps we could get him to post it here?
Would love to see it, and I could care less what brand quad he flew it with! We all have the same goals, and in the end, they're all just contraptions flying through the sky based on identical principals.
 
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#9
Would love to see it, and I could care less what brand quad he flew it with! We all have the same goals, and in the end, they're all just contraptions flying through the sky based on identical principals.
Here's one that I tried to do following a river (dirty one). I'm using the "other" contraption. Their were several things that I was trying to accomplish, one of them was following the river. It does take some effort and time to adjust for the curves. I probably spent 2 hours planning this 13 minute run. I made it for Raybro as we both like running waypoint flights. It's in 1080p.

Jerry

 
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#11
Guys, don't forget that you can draw a path in Tower using your finger (recommend a stylus). Just draw it along the course of the river. I've done this numerous times.

Having said that, spline waypoints or regular way points should be fine. Splines take a little tweaking, but it should be easy to lay a course out on a river. Regular waypoints should work too, if you tweak your Params (i.e. more space around waypoints as the OP mentioned - but try 15 feet, not 5). 3DR birds used to jerk a bit at waypoints, but they've fixed that. You might also want to set an ROI or two along your path to help keep the river in frame as you go around sharper bends in the river. If the river isn't too windy, just one ROI positioned beyond your last waypoint (with a low altitude set) should do the trick.
 
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#12
Here's one that I tried to do following a river
That's great! It just amazes me that for between a few hundred dollars to a grand, we can buy or build a battery powered VTOL aircraft with the ability to go out and fly complex, autonomous flights - reliably, and transmit real-time, stabilized, HD video of the flight to top it all off!

I really can't wait to start sending the Solo out on autonomous flights.
 
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#13
I haven't tried spline waypoints myself (next on the todo list) but I did see some nice footage of an IRIS following a spline waypoint and I was impressed with how smoothly it just seemed to turn from one waypoint into another.
 
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#14
@rrmccabe has a very cool video he did with his white one that showed that exact type of path. It was a very neat video that you would enjoy, even if it was done with a different quad. Perhaps we could get him to post it here?
Jub, trying to figure out which video you are referring to? Would be happy to post it if I know.
 
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#15
Jub, trying to figure out which video you are referring to? Would be happy to post it if I know.
Hey Rich, You had posted it long ago, but it was the one where you dropped down and flew along the river, at one point you cut it pretty close to the tree tops! Very cool video.
 
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#20
In Tower or MP, what's the best way to get smooth flight paths along random curves? I'm finding it difficult to impossible to replicate specific curves using spline waypoints. There's a small river I'd love to fly down, but there are random curves and straight sections that seem to thwart any attempt to lay a flight path right down the center.

At the same time, my flights using straight waypoints seem pretty smooth - the quad does a nice fly through the corners as opposed to stopping, rotating towards the next waypoint and continuing. I think in the flight controller's parameters I have a 5 foot radius set, so as long as the quad gets within 5 feet of the waypoint, it checks it off it's list and continues to the next.

So that makes me think it'd be better to use a bunch of normal waypoints than a few splines. I'm going to test this over the next few days, but I thought I'd ask if anyone else has run into this.
If you would like to fly curved missions, take a look at an Amazon ebook entitled "Gently Curved, Convergent, Non-traditional Drone Flight Paths". You can now plan your approaches ahead of time to get your spectacular photos. Compare actual traditional (linear/parallel) flight paths in the first example (attached file) to the curved non-traditional (non-linear/non-parallel) flight paths (second attached file).
 

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