Free-Flight Glider Control System!
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- Опубліковано 3 жов 2024
- This video features testing of a homebuilt RC glider equipped with an autonomous pitch and roll correction algorithm. It works using an Arduino Uno, BNO055 accelerometer/gyro and TF - Luna LiDAR sensor.
#arduino #rcplane #homegliders
Music: "Believer"
Comment how you think the design can be improved!
I suggest looking in to basic aircraft setup in regards to what makes a stable model. There are many great books on model aircraft design. The first thing I noticed was the twist in the wings. It doesn't appear equal and is in the wrong direction. You want less angle of attack at the tips than at the root, something known as washout. It looks like you have the opposite, which is causing the tip stall, and the aileron trying to correct the bank angle is only aggravating the stall by increasing the angle of attack on the stalled wing. You can correct this problem by adding washout and reducing the downward movement of the ailerons.
Yes, I think you're right on the wing twist in terms of the ailerons, I had to add some ballast to the right wing of the plane as it was consistently banking left. The ailerons were limited to a 16° deflection angle already so I'm not sure it can be reduced farther. How much washout do you recommend implementing for a model at this scale?
@@HomeGliders You can add a substantial amount of washout, 1-2cm per m of span per wing. Only use ballast to balance the wings, not to correct aerodynamic inaccuracies. If your servo control unit allows, program for less down travel than up travel. You can even go to zero down travel using only up aileron travel as spoilerons. This also has advantages in regards to adverse yaw induced by downward aileron input. If your servo control unit does not allow for programming up/down travels independently, you can create differential throws by changing the linkage geometry, something we used to have to do before computer radios became available.
@@HomeGliders I just realized you may or may not be wondering how to change the twist in your wing. You can usually get enough of a change just by manually twisting the wing while applying heat from a heat gun or hair dryer on high heat. The covering will hold that shape for a certain amount of time or permanently if you are lucky. It all depends on the covering and the stresses built into the wing structure.
Thank you for the tips. I'm looking into rigid skin designs now specifically to avoid warping and excess stress from the covering. I think it's a bit tricky to build in washout that way, though
Another Tim banger
Interesting! It seems like the control want to pitch the nose up causing stalls. I think it's better to have the set point to be a little below 0° forcing the nose down! Also did you use PID or bang-bang control system? It looks like a bang-bang from your video and explanation. Great work!
That's just my opinion, please correct me if I'm wrong :)
The setpoint in that video was at 1°, I might try -2 degrees next. This algorithm used a stepped bang-bang system rather than a PID for simplicity. I can post the code if you want :D
LOL. You don't have to run to launch the glider. With your throwing hand, hold the plane's fuselage from beneath near the center of gravity and push it into the air as if you're throwing a spear, but gently and level, straight into the desired flight path. Or go find a bigger field.
Thank you for the tip, big fields are hard to find these days haha