Rocket guidance and flight trajectory control

i remember you seeing this

Big fan sir ❤

Your just going to let em show you up like that?

Can't believe BPS space is actually commenting in here

Roses are red, violets are blue... 😂

Were the engines full throttle?

@@haydentravis3348Those looked like demonstration engines only. You wouldn't want to try a maximum performance flight until characterization testing was completed.

it will suddenly know where it is. because ultimately, it knows where it isnt.

American DIY content be like

@@corruptedmineral 'murica!

@@corruptedmineral Hate to break it to you but, this takes place in china. You can see at the end of the video it even states NUAA. stands for "Nanjing University of Aeronautics and Astronautics" most of the development software was in Mandarin as well.

@@AssassinGT most places in china have absolutely banned drone flights of any kind. They're afraid of "the people". Imagine if chinese have access to 3d printers and a chemistry lab? Yea, they could launch a rocket attack on pretty much any CCP asset.

I haven't checked the legislation in 15 years but I do remember model rocketry getting a lot of scrutiny in regards to their onboard control systems. They were only allowed very rudimentary controls if you had anything like in this video the feds would have probably locked you up for domestic terrorism and manufacturing guided missiles. Be very careful when even considering making something similar, check your locals laws and such and never assume good faith from law enforcement. Those days are long gone.

If it was that simple "algebraic sum" :) It should use some PID, because relation between how wings are adjusted and how should be set. Depends on various factors like for example speed or size of wings. Greater the speed lower the feedback should be, but not always if it would be too loow - SpaceX lost fuel, could not adjust it's position fast enough and fliped over. To not cause too much correction than necessary causing in consequence loosing it's trajectory in opposite direction - making it even worse. Simple PID should be set, to set P and I and D module properly you have to test it couple times. One to react quickly over-reacting, other integrating change add some "trim" and third simply multiply by some factor I hope you know all of this, just wrote for everyone else - it's not that simple, although more or less, way you described. Perfect algorithm would "learn" during long flight could gather information and subsequently adjust PID parameters to end up with minimal deviation. It's difficult if you deal with rocket.. to learn i hope they continue for example set goal of hiting target like baloon or something in the air :) That would be cool. First baloon with GPS attatched and both connected. Second time only visual. Private defence system :)

Beat me here.

I knew I'll see this comment

You win the internet

Classic

Joe Bernard

wait, missiles have a center of lift? i tought they worked with high twr's ? and another question, what if they don't have one? or is it even possible?

@@WarDucc Anything has a center of lift. It's the point where all integral aerodynamic forces are located. You know, the wing surfaces generate lift and drag - which are nothing but two components of a force vector. These local force vectors can be integrated over the entire craft (as any surface will create some drag, therefor an aerodynamic force) and you will have a vector that has a direction and an origin, and said origin is called the center of lift. Since lift forces are usually orders of magnitude bigger than drag forces (at least for high angle of attack configurations) we call this principle "Center of lift". It plays a crucial role in vehicle stability. A stable system will always try to orient the center of lift behind the center of mass for a moving object. The feathers on an arrow demonstrate that principle very well. You put them on the end to keep the arrows flight path straight. A slight deviation from the straight orientation will increase the angle of attack on the feathers and force the arrow back into a straight flight path. This means a deviation is met with a counteracting force and self balances the object. "Straight as an arrow" comes to mind. If you put the center of mass behind the center of lift, the opposite happens: A small change in angle will, again, create a force on the guiding surfaces of the vehicle. This force, however, is now acting in such a way that itself increases the angle of attack even further. This results in a larger force, finally flipping the vehicle such that the center of lift now is behind the center of mass. The thing about aerodynamics is, that lift and drag are functions of the Reynolds number. Changing flight conditions will result in changing aerodynamic forces. You need to account for all states of flight to ensure your vehicle is stable thoughout. Especially the transsonic regime is acting up, as many properties of airfoils change dramatically in this environment. I somehow doubt that this was a consideration on this project though. To conclude: Jettisoning the lower fins simply removes their aerodynamic forces from the overall integral of all force vectors. If you remove a vector far away from the center, it will effect the resulting position of the center significantly. The rocket basically turns the direction of the arrow mid flight - from having "small feathers" up front and "big feathers" in the back to only having "small feathers" in the front, making it the new rear of the arrow as it inverted.

@@WarDucc well, rockets have a center of lift and they are essentially oversized missiles. For missiles, center of lift isn't about generating enough lift to take flight, it's about keeping the missile stable during flight. If the center of lift is ahead of the center of mass in the direction the missile is moving, then the missile will attempt to invert itself, since the center of lift always tries to stay behind the center of mass for stability. To counteract that, missiles have fins on the rear that push the center of lift behind. However, when the missile is vertically falling and the parachute is installed on the nose, then the original design is very unideal, as the missile will now try to fall nose first to maintain stability. To counteract this, we need to push the center of lift further up the missile. The team here achieved this by jettisoning the fins, which pushes the center of lift further up so that the missile can fall thruster down.

thanks!@@davidlee1770

But why not connect them to the fuselage with a thin cable?

@@eh6971 Are you saying to raise and lower them? that would require some sort of actuator or spring based mechanism to move them, the reaction forces would probably be weird too. ejection is probably the least complex mechanism to remove the fins and make it so the rocket naturally wants to point down after it hits the highest point in its travel.

@@qualifiednot I think he means using a thin wire to retain them as they eject

What is the purpose of ejecting the fins at the rocket's apogee? You mention changing the COP, but to what end?

@@evanweir169 fins causes more drag at the back of the center of the mass thus would make the rocket wanna point towards the ground on the descend so they couldn't use the parachute effectively . Wires on fins could still cause the same effect as fins would float up relative to the rocket on the descend and would still be pulling the bottom of the vechile and force it to point downwards .

If you student of that university please contact with me

Undergrads? These dudes are hardcore

obviously? new generation is always more advanced with the amount of resources and total knowledge increasing

Yep you are right, there is always a percentage of people who are interested in different things, and the harder things are there will be less people interested in, or specializing in. There is nothing easy to watch TikTok all day, and the hard things, for example learning how to make missiles, drones, planes cars....​@@ege8240

台灣造火箭算了吧,全台頂大加總搞得飛鼠還不如人家一個本科社團的東西有看頭

这些人毕业后可是要去造大火箭和军用导弹的。

​@@Proempireking等你捐款啊～😂😂😂

绝对地！ 作为一个英裔美国人，我也会做同样的事情。 做得好！

这哥们是南航的大一学生，最早视频发bilibili的@@Proempireking

ive seen more stable fireworks ]

With control engineering background, I don't think it looks hard. A simple pid controller should work. The hardest part comes wih trajectory control which in turn boils down to navigation part.

@@TrungNguyen-mj2idas someone with a control engineering background, this is not an easy project to pull off.

as someone with a control engineering background, this is not an easy project to pull off.

@@TrungNguyen-mj2id as someone with a control engineering background, this is not an easy project to pull off x3.

As in a nuclear bomb flash type of a bright future

hi micheldriessen, have you become a flat earther yet?

@@flat-earther meow

hi eliteworm, have you become a flat earther yet?

Most importantly, it looks like China has made a mechanism that brings creativity into creation.

@@AhmedAdly11 what do you call the mechanism. the one that brings creativity into creation?

@@evanweir169 one good mechanism is supporting students to carry out projects. In Egypt, such a project would be banned on the basis of national security. (it is a 7 year jail for using a drone)

​@@AhmedAdly11 it's really sad that they kill the people's creativity and productivity.

@@kioly_ah If you come from a free country, you could not imagine. Military dictatorship is a horrible thing. China is lucky in comparison. Also, they went from dark to light! So what we see now should be considered incredible leaps forward. Also that they will continue in that direction.

Next step is adding this inertial nav to a model airplane. After that, TERCOM via optics

a missile by definition is guided

You better understand what you wish for in the context of geopolitical paradigm

@@gybob100 it is shifting

Theres only two thing missing in the rocket, copper and some explosives 😅

​@@trollmanman5576that's on our channel lol

@@trollmanman5576 just one Copper rod and a cone away from being an ATGM

If your IMU is mounted with separation from your COM, then it will detect spurious linear accelerations when the vehicle experiences any sort of angular rate or angular acceleration. Provided that this is characterised beforehand and filtered out of the IMU output, there should be no issues.

Hey Wulfleyn, appreciate your sense of humor! Just to clarify, the kids in the video are actually from China, not Korea. While their technology might not be on par with military-grade missiles, it's still fascinating to see how far technology has come and how it's accessible to people of all ages. Cheers! 😊

@@lshang882 Oh sorry, still cool though, I have problems with distinguishing languages in general so sorry for that.

​@@wulfleyn6498 can these kids make hypersonic ones ??? Russia has 1 u.s has 0 maybe you need to open your eyes to reality

Nik lyhoud hhhh

pretty sure any american who watches this would be put on a special government list too so, not too far off

AGH robi rakiety głupi mośku.

​@rickson50 Basically, the rule of thumb is to keep it vertical, also no targeting systems. You break those rules, well, that's a felony

Join a rocketry club or create a KZhead channel? As long as you have a valid reason the powers that be seem content to leave people alone.

⁠@@noahw4623t is actually perfectly legal to design and build guided rockets in America. We have the 2nd amendment, after all. If they have explosives attached, then it is a little more complicated but still possible. Testing them can become a lot more complicated as there are FAA (surprisingly not ATF) regulations that prevent guided rocket testing without special permission. Guided meaning that it lands in a specific location. It’s a lot easier to design, test and deploy autonomous loitering munitions that do not use rocket motors, like the switchblade drones and the like, these days if you are a budding Tony Stark.

Tbf most cutting edge is in that sector

Pretty sure so that the rocket flies straight down before recovery parachutes deploy

@@bb-bricks3040 I think you are correct. I don't understand why they want the rocket traveling straight down. It sure seems like it would be hard to find those fins again. There's probably a good reason for doing it this way, I just don't understand it.

@@ddegn if you can see those fins on the back help control the rocket and the top (or front) part is chamfered for aerodynamics. Because of their 90 degree trapezoidal design as well as the positioning (you don't want control fins on the front of your rocket), they would negatively affect its aerodynamics.

@@bb-bricks3040 I can see how ejecting the fins improve aerodynamics, I just think it's an interesting choice to discard the fins. I wonder if the fins are considered disposable. It sure seems like it would be hard to find the fins after each launch. Of course with 3D printing those fins could be replace with very little effort and very little cost. My wondering about the fins shouldn't be taken as criticism of the rocket design. I think the rocket is amazing.

Because I want the Rocket to maintain the upward attitude in order to control the trajectory of the decline process, and I will try to use a reverse engine to land in the future.

hahahah the guys is not on missile business..

Hamas doesn't even need that...

i mean id like that too but tbh i feel like such systems most likely fall under multiple countries regulations of weapon systems just like passive radar code and so son with the kraken SDR not sure if Japan has such regulations not to mention the huge amount of risk this would add for terror attacks and other things like assassinations which in japan are pretty on topic rn so i think the release of the code would be more unlikely, although this may be sweet to send the FSB a present from some activists in Russia this would be hecking sick for causing chaos inland russia

kzhead.info/sun/lp1tkqWEeJl7gYU/bejne.html but maybe this would help ya to some extend

I believe this was developed within a University institution and I don't think China has any interests in making such projects open source.

​@@danielevendrame9350 Hong kong

It would get beaten the shit up by ITAR

You kidding?? Those 47 genders could be weaponized as "freedom" bullet