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Visualizing Quaternions: https://youtu.be/d4EgbgTm0Bg
Thanks for the data, Jonny! https://jonnyhyman.com/
Contact: https://bps.space/contact
Echo – Landing Test #4
Visualizing Quaternions: https://youtu.be/d4EgbgTm0Bg
Thanks for the data, Jonny! https://jonnyhyman.com/
Contact: https://bps.space/contact
Excited to see what you come up with. You have serious talent. Great job!
Man! I keep scoring on the prize for the first person to watch your video all the way through!
That, or you still think I am Scott Manley.
(Neither this post, nor my channel are frauds. I just happen to spell my name the right way. =P)
It actually looks like the failed SpaceX droneship landing when it run out of fuel (besides the X-plosion)
It’s awesome to see the improvements in each video, very satisfying.
I really hope this fly got a SERIOUS warning ⚠️ !!! 😜🤣👌
Good luck my friend. Love these kind of one man projects.
Tbh you look like elon and zuck had a baby
Not an insult. I like these videos
Maybe land the boosters/ core on a baseball diamond? Maybe that tall grass is catching on the legs at horizontal a little? Don’t know the dry mass of these things. Just an observation.
Totally enjoying the progress and development process. And thanks for the somewhat technical explanations. Feel free to get a bit more techie, i.e. make us stretch. The lack of throttle control is such a key factor. Amazing that you’ve gotten so close to a soft upright landing.
These model rocket engines are not throttle-able. Amazing you can control this. Great stuff.
why dont you adapt a flight controller like the Matek F405-STD that have barometer , faster F4 micro and data logging
“It’s a lot easier to balance a broom stick with one hand than it is to balance a pencil” – Jeff Bezos
An idea i have for you. I see your working on the RCS system too. If you need an assist with the landing, you could use the residual gas as a retro thruster. Almost like how the Soyuz capsule has retro thrusters for landing. But you could either rapidly fire the gas retro thruster or just release at a constant rate for a more precise, constant, and soft landing.
if you haven’t already, would you consider making a breakdown video to ease the learning curve/ introduction to your videos? almost like a dictionary of terms/ phrases used? cheat sheet as it were… wouldn’t expect it to be super basic nor would I need it to be but it could be really helpful to getting more people onboard with a better understanding of the more technical aspects of the videos in the past and future! Great work and thanks for sharing
Great work. Maybe separate the gyros some. 1 at the tail and 1 at the nose. The greater the distance between them, the more accurate the measurement sent to the main processor and the more accurate the control response. Also, while the fixed vanes near the nose assist in your vertical orientation during descent, making them steerable via inputs from the upper gyro (along with tying the gimbled nozzle to the lower gyro) should eliminate the vast majority of the tilt in any direction, as well as minimizing lateral drift.
I would suggest the addition of a gps unit linked into the gyros, but units that small and that accurate are limited to military usage for the time being.
A channel that shows content before intro/ads/10min rambling… respect
I’m
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I would suggest that you try removing that last 10cm by allowing for impact to occur with a little bit of velocity remaining with a sub-power engine (with some very small landing pins on the legs)
This would remove the control the thrust vectoring has after landing but it could not take back off so thats a win and would look great on video
Would dropping it from higher offer more time to passively stabilize so you can use the LIDAR without having to worry about tipping too much?
Could you improve your altitude measurements by cross-referencing barometer data with simulation data during tests, then fine-tuning the simulation?
Honestly think you need just a slight amount of more weight…perhaps lead or tungsten penny or quarter on the landing leg tips.
Shouldn’t you be using curved fins, like you would on the final rocket? Ideally, you should be using the same fins that you’d be using on the final rocket, but you could just have fixed curved fins for the test vehicle. On the other hand, using flip-out fins might impart a rotation along the vertical axis as they unfold, and you’ll definitely want to test for that.
Also, try reverse-biased LEDs as your SRB ignitors. If they’re hooked up backwards, instead of lighting up they’ll let out their magic blue smoke on the millisecond timescale.
Finally, other people have suggested shock absorbers on the legs, which is a good idea. Having six legs instead of four would also help with the landing stability.
About the drift and hover on touchdown, to what extend do ground effects influence that?
And what is the ratio between the forces involved and the mass of the rocket?
Why are you adding complexity with pop out fins and center of mass shifting (and multistage for relanding?) instead of just doing an initial iteration of going up (engine and fins on bottom) then allow the drop to flip the rocket and a separate motor in the top to do the land?
So, just rocket up -> fall and allow flip with fins up and the heavier unspent engine down -> land
Use aluminum foil, folded up on itself. Construct a strut attachment that deploys with the opening of each leg. As a mechanical engineer myself, if you’d like, I can design a simple to construct and lightweight configuration for you. No charge.
Pulling a musk
Remember it took him years to land his first falcon nine booster. Keep trying!
What you’re doing is amazing!! Love watching these regular updates, it will be great to see it work!!
Nearly perfect landing, congratulations!
I love you, you’ll get it next time!
This was so close! Great job! Cant wait to see what’s next!
I recently learned from my work with model rockets that kinematic equations are not sufficient to model the trajectory of a rocket at any extended path along its trajectory. Kinematic equations are actually based on truncated Taylor series approximation of Newton’s laws of motion, and are not accurate enough, even with an infinite number of terms, to model a system with varying mass or drag. While the error is negligable in many cases, it seems that it is subtantial enough in your case to affect the rocket as it descends the last few inches. Tweaking your physics-based altitude algorithm might be adjustment needed to land the rocket exactly on the ground
Hi! Amazing job. Did you consider to use laser distance sensors for measuring altitude of the rocket during landing stage? This way you can trigger whole landing sequence more precisely.
I’d make those landing legs slightly longer to decrease pressure during landing and also increase stability. so you have a higher increase in landing the rocket.
The grass is literally the only place you can land, so I would buy some thin material to cover the grass so it lands evenly on the ground.
Wow, what an impressive effort! You clearly know what you’re talking about and present your work really well. : )
Could you not print the landing legs in a more flexible filament, like PETG or ASA? You could also add TPU feet, which should also be able to dissipate some energy.
Never thought I would see this on such a small scale! Amazing work!!
Off-road radio controlled car
Oil damper
If you put it on the foot of a rocket, it may not bounce
When I first saw the rocket get dropped and fire up then slow down to a stop surrounded by smoke, I thought you had stuck it perfectly! So close, I cant wait to see the the rocket launch and landing tests. Brilliant project, I am rooting for you buddy…
Congrats kiddo! How bout some shocks? Crush core…would be lighter…
Chas
I know it’s not practical, but what about a solid and flat landing pad… Once the the vehicle gets more accurate with lateral movement
Fascinating! Love all the software stuff. Looking forward to the day you can say: LANDED IT!
Really cool project. Thanks a bunch for sharing it with us. Just side note though. I cant believe I had to go through 4 videos to get to one landing. Man this droned on for for EVER!
Deploy landing gear BEFORE igniting landing burn!
– Simple thing works >8+D~
Amazing…Its amazing that you can control rocket with “solid fuel”…!!!
Idk about you but…
“I’m running out of whiteboard jokes”
Congratulations, I love to see the progress you are making! keep it up, next time perfect landing? Fingers crossed!
Dude!! So close, I reckon you’ll land it next time for sure..
Have you considered making a landing platform.. this might mitigate the bounce.. but then your only challenge would be to target said platform from 30 meters up.. (lidar??)
Looking forward to the next episode..
Cheers from Australia
Nice job Joe!
Try replacing the current fins with some thicker ones that also are more aerodynamic.
Hey Joe, if it is really you ❤️ the comments..Please tell me (this might be a stupid question) how far off is the software for Thrust Vector Control from a one for a full-size rocket. Or rather how much if any can you scale the rocket and use the same software and procedures. Thanks.
I am the guy that you and Tim meme’d on twitter about the consistency of the burns. GG. For real tho, I think it would be crazy if you had a permanent range where you could set up fixed cameras and do some mocap/3d spatial mapping – imagine the data overload that could provide.
You can always try to reduce drift in attitude and position estimation with better filtering, however with the sensors that you are using you can’t avoid having some drift (namely given your sensors your system is not observable). To avoid position drift you could maybe use optical flow with a down facing camera, but maybe you can reduce the drift enough with just filtering.
Thanks and congratulations on the progress !!
Serious question. Could you include some drop tests from a height where the acceleration is approximate to the expected acceleration prior to engine cut off ? And could this be done at the launch/landing site ? This would be to observe the expected bounce from the landing gear, as well as any “reflection” of the landing rocket from the grassy surface.
Watching this landing, in that environment, makes it easy to believe that out of 5 drops from about 60 cm (2 feet), might result in at least 2 topples (technical term) of the equipment.
This may already be tried in an earlier video, if so, never mind.
Keep up the amazing work !!
Try dampeners for the landing legs
turn off guidance system when legs are deployed, after the vibration occurs, turn on sys again
Use a plain surface u genius!!
Awesome job Joe!
As far as igniters go, maybe get together with ElementalMaker. He did igniters on his channel. Maybe more consistent if you make them yourself.
I think you got this. But i think you need to add more weight into the rocket. I think it is too light. When it drops on the ground it bounce and fall. Maybe you can add more weight into lower part of the rocket and it helps to stabilize the rocket after the first touch down.
Just curious,
What is your monthly budget to spend on your rockets?
Amazing work! I would suggest servos for vehicle release and landing gear deployment. Much more precise timing and control available, and it’s probably no more difficult… Keep it up!
I’m running out of whiteboard jokes….
Naaah… Keep up the good work, you are so close !! … I hope all the best for it to succeed, and although I don’t understand much about rockets…
But is it possible? Aren’t the motors to unrepeatable and allways have a slightly diffrent power?
edit; Just noticed you talked about it.
Generally in R/C you can expect 5% error. But after testing, those motors have arpund 1-2%.
Much bigger problem is setting them off
Amazing drawing on the board in the background by the way – dude I admire you and your work a lot! Keep it up!
Thank you for calling it a UAV instead of a drone.
You are so good at explaining things!
Hi Joe. Great video.
Knowing when you deploy the landing gear, can you mute or increase the dampening of the gyro signal for that short instant?
Why do you look suspiciously like Elon Musk?
“I’m out of whiteboard jokes”
I think the rocket will get into a Spin with those fins 2:42 . I love your content.
Definitely just realized you have been putting jokes on the whiteboard. Now i’ll have to rewatch all your previous vids!
And damn good job on that landing – dunno how you have the brain power to solve all these physics issues, especially with high tolerance equipment/environment.
You definitely need a new type of thrust. Those rocket motors don’t have control.
Hey Joe I see you’re running out of whiteboard jokes
Modify the landing legs so that they ABSORB the shock,
Roger Garrett is on the right track
What if you eject the motor vertically through the airframe upon touchdown? Motor retention could be actuated slightly before or at touchdown (TVC System would need to be vertical obviously). Motor ignition could occur at some moment slightly later than you’re currently running, to guarantee you’ve got motor impulse remaining to stick the landing.
It seems you’re more inclined to software side tweaks. Also my suggestion would require structural modifications that could prove unrealistic (clear space through the rocket forward of motor retention)
I think that you need to upgrado those landing legs, My reaction to the test: oh jesus crist that was close!!!
Could you use multiple lower powered engines to balance rocket motor variability?
9 is a nice number!
use tiny syringes as struts, that would dampen the landing gear on deployment and add impact absorption on touchdown. (coat the inside of the syringes with mineral oil to reduce the static friction coefficient)
Amazing to see the progress your making! Keep up the great work you have one of the most interesting channels on all of YouTube!
Magnets on the feet and a steel landing platform!
Damn I hope this goes well
Edit: Darn, That was soooo close! You’ll get it next time.
Hi Joe,
you should contact ST Microelectronics about their latest LSM6DSOX Sensor. They are one of the best IMUs I found on the open market.
Greetings,
Moritz
Awesome, your so close !
Do you take into account the change in mass while the motor is burning in your motor ignition timing calculation? Because 13cm sound like the result of the rocket descelerating to much at the end of the burn ^^.
Anyway, congratulation !
Cant believ your pulling this off. What’s next Backyard fusion energy.
Wow I’m such a better person because of watching this video. What a wonderful experience it was to sit through all roughly 17 minutes of it. I‘ll never be the same and I feel bad for everyone who didn’t watch the whole thing.
“I’m out of whiteboard jokes.”
-Joe’s Whiteboard
Very well done Joe. That was so close on such a difficult surface. If that thing had your RCS it would have probably stood upright. Best of luck with the next tests.
This video is a *master piece*
Sensor fusion! Slap a kalman filter on everything and it’ll probably fix a bunch of your sensor issues.
Right now you’re using only one of your sensors at a time and cutting between them as you change flight regimes, accepting the downsides of each in turn. You don’t have to do this – there’s math that will let you throw all of your measurements into a single state estimate and gain something that’s close to having the best features of both sensors. The accelerometers continuously recalibrate the gyros, the gyros provide high-resolution angular measurements, the barometer keeps the accelerometer’s altitude information from drifting, and the accelerometers provide high-resolution altitude information. You can even manually tune the amount of noise you expect from each signal over what time scales.
Sensor fusion also works with multiple sensors *of the same kind*. I’m impressed with the performance you’re getting given how slowly you’re observing your sensors; when I did humanoid robotics we wanted to be measuring important sensors at multiple kilohertz. But buying more expensive single sensors isn’t necessarily the only way to improve measurement frequency. You can also mount multiple low-quality sensors and throw them all into the update step of your filter. Even if you measure them all at the same time it’ll probably help you reject some vibration. The real win would be sampling them out of phase, which would give you a better chance of capturing large transients like the shock you get from dropping the legs.
I apologize if this is something you’re already doing, or if you’ve already rejected these features because they don’t fit into project scope or available computational resources. I only watched this video and looked around on your website for a few minutes. But the part where you’re cutting between sensors entirely makes me hope that this will at least provide some paths for improvement. Good luck!
Joel, could you use hobby shocks like what is on RC cars for landing? They can absorb very well hard landings. Just a thought.
Good job on your progress!
“These are model rockets, like, you can´t take it too seriously” – Says the guys landing them with solids😂
Great work Joe…I have a suggestion or two…
Unlike you, I’m not a rocket scientist but I think the landing surface is possibly another contributing factor for the vehicle tipping over…
So, why not design a portable firm landing surface…
Idk what is the proper term but getting a working retro system that would aid in orientation of the vehicle and possibly eliminate the sliding issue….
Finally, for the legs, would a shock absorption system help to eliminate the bounce also. ..
May your skies be always blue and Godspeed in you endeavors….
Congratulations to this nearly perfect landing!
Greetings from Germany 🇩🇪
I teach an aerospace engineering class to high school students. We just watched this video, and they lost their minds!
omg joe, you are so damn close to sticking it, I cant wait to see the next test!
So you ran out of whiteboard jokes
This was so close I thought you landed it when I saw your tweet 👏🚀
“These are model rockets. You can’t take it too seriously” 😂
Witeboard in the backround:
I’m
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Modify the landing legs so that they ABSORB the shock of landing rather than bounce back from the shock.
This is just an elaborate job application to SpaceX.
Respect
Just as a reminder, this video was sponsored by CRAP. Concerned Rocketeers Against Parachutes. To become a CRAP yourself, go to https://bps.space/crap