@@haydentravis3348Those looked like demonstration engines only. You wouldn't want to try a maximum performance flight until characterization testing was completed.
Damn did you guys really basically build a missile from scratch by yourself? That is insane. It also looks really slick the flight looked very smooth. Very impressive. Can't imagine the amount of work that went into it.
@@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.
The idea to stabilize the descent center of lift vs center of mass by jettisoning the bottom stabilizers is amazing, love your project. Its actually first non-sounding (actively stabilized) rocket i see on YT
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.
@@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.
@@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 .
The quality of craftsmanship in your videos is impressive. Not only are the concepts you are working with at the high end of things people can even understand, you do it with a build quality that matches industry items. Well done and keep it up!
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.
The missile knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't. In the event that the position that it is in is not the position that it wasn't, the system has acquired a variation, the variation being the difference between where the missile is, and where it wasn't. If variation is considered to be a significant factor, it too may be corrected by the GEA. However, the missile must also know where it was. The missile guidance computer scenario works as follows. Because a variation has modified some of the information the missile has obtained, it is not sure just where it is. However, it is sure where it isn't, within reason, and it knows where it was. It now subtracts where it should be from where it wasn't, or vice-versa, and by differentiating this from the algebraic sum of where it shouldn't be, and where it was, it is able to obtain the deviation and its variation, which is called error.
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 :)
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
We used to play with rockets 35 years ago. But with what is available now, you have a world of exploration extra. Nice job ! Keep up the fun for the rest of your lifes.
Tam beklediğim performans. Çok güzel çalışma olmuş. Zekice düşünülmüş bir sistem. Roketin kalkış esnasında yalpalanma olmaması için eksenini düzelten bir kanat sistemi (gyroskop ile ) yapılmış. Cidden çok havalı ve güzel. Tebrik ederim.
@@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)
@@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.
Everything looks so well made! Awesome work! how long did it take from start to good launch? Did you use any open-source software? In particular for flight control or cad designs?
After watching this video thoroughly on multiple occasions. I can confirm without any doubt that the missile knows where it is at all times. (It knows this because it knows where it isn't.)
I have been wondering, how important is it to place an IMU at the exact center of mass? It looks like most systems keep the chips very close to this center, but a few millimeters off of the center doesn’t affect accuracy in any negative way. Beautiful work on this guidance system!
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.
@@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.
Chinese kids having more advanced guidance tech than russian military missiles is pretty funny. Edit: called them korean when they're chinese, bit of an oops.
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! 😊
I like how you guys can build this stuff. In Poland they would hunt down such engineer and prosecute him until he would "shit himself". Great work with sensor fusion algorithm.
@@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.
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
The missile knows where it is at all times. It knows this because it knows where it isn't, by subtracting where it is, from where it isn't, or where it isn't, from where it is, whichever is greater, it obtains a difference, or deviation. The guidance sub-system uses deviations to generate corrective commands to drive the missile from a position where it is, to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position where it was, is now the position that it isn't. In the event of the position that it is in is not the position that it wasn't, the system has required a variation. The variation being the difference between where the missile is, and where it wasn't. If variation is considered to be a significant factor, it too, may be corrected by the GEA. However, the missile must also know where it was. The missile guidance computance scenario works as follows: Because a variation has modified some of the information the missile has obtained, it is not sure just where it is, however it is sure where it isn't, within reason, and it knows where it was. It now subracts where it should be, from where it wasn't, or vice versa. By differentiating this from the algebraic sum og where it shouldn't be, and where it was. It is able to obtain a deviation, and a variation, which is called "air"
Just when I thought I was an "engineer"; all those young man are TRUE engineers. Probably in a thousand years I will be able to scratch 2% of what they already know... Such a charming thought, isn't it?
