I want to get as close as I can without having to go through many motors. I’ve heard the best approach is making a simulator (simulink, etc). However I am new to this, what is the best guide in doing so? I understand PID pretty well and how they affect each other, but need help setting up a sim. I’m using two servos (controls x and y). I was initially planning on making two PID loops (one for the x and the other for the y, mainly for simplicity).

any solid rocket fuel engine recipe i can make using urea (fertilizer)?

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Me and my classmate want to do research about TVC in model rockets. However we are struggling finding the relevance of our research.

Our research question is: ways to stabilise a model rocket.

Help would be appreciated.

Sorry if this is a duplicate post, but as the title says, where do I start? I have some prior knowledge with this kind of thing, but what I really need help with is 2 things :

• How in the heck do I program the thing? I would prefer to use C++ (Arduino code), but I don't really know how to write that. I'm sure I could learn, but how exactly would I use those skills to program a TVC rocket?
• How and in what order do I connect all of the electronics? I already have one of the things needed from a previous project, (IMU). Also is there like a list of the electronics I need somewhere? I’m planning to use an Arduino for the flight computer if I can, and piece together the rest with off the shelf components.

As far as the actual TVC mount goes, I already know how to do that. (Micro servos, and for me 3d printing the actual TVC body.)

(Last thing I thought of : do I need a reaction wheel? Is it imperative?

Thanks!

Hello guys! I'm a newbie here and I was wondering if I could receive a few insights to a schematics I'm trying to develop for my TVC model rocket. In the image you can see the schematics I'm trying to use. I did follow a tutorial on YouTube and I have a few questions to ask:

- my friend, who's coding for the TVC wants to know where the TVC pins should go. I do know that the two headers on the top left are used to connect the servos but he wants to know, exactly, what pin he should put into his code. All I can tell is that it connects to the VIN (voltage in?)

- I was wondering if I should be using an SD card holder to store data to analyze post flight or if there are better alternatives. Could someone also aid me in where I could connect the SD card if I am to use it?

- I was wondering if it is necessary for me to use the MPU6050 AND another sensor like the bmp180. If both aren't needed there is no need to help me with this but if the BMP180 is a good addition to the build I'd like to know where I could install it on my schematics

- Are the '5V' tags in between the lines where the battery is connected to? if I were to build this IRL where could I connect the battery to?

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https://preview.redd.it/0xrj4bvjxrgc1.png?width=1111&format=png&auto=webp&s=32c2a5ef9dbbd2a35ad9c25bc56953486cec9cdb

I'm a beginner who would appreciate guidance with getting started with flight software specifically with the imu part.

So, I'm running an MPU6050 and a teensy 4.1 and I'm wondering if it's best to develop my own library or use an existing one like Jeff Rowbergs one in order to get raw gyro data. The reason I'm asking this is because some people say to develop your own library and some say it's fine to use an existing one. Is it even feasible for a beginner to program their own library for an IMU?

Thanks in advance.

My idea is that we take for example the Xval from the sensor and instead of just sending it to the Xservo we split it up in to XvalX and XvalY and multiply them by the value on their sine wave with respect to Roll as seen in the upper half of the diagram and also multiply them by Xval. Then we repeat this for Yval and add before feeding it to their respective servo as seen in the lower part of the diagram.

Example: Xval: 10° Yval: 5° Roll: 270°

XvalX = 0% (Proportional to Xval (10°)) ≈0% XvalY = -100% (Proportional to xval (10°)) ≈ -5%

YvalX = -100% (Proportional to Yval (5°)) = -2.5 YvalY = 0% (Proportional to Yval (5°)) = 0%

Xservo = -2.5% Yservo = -5%

As you can probably see I'm very unknowledgeable about control theory and maths/physics in general so there is probably a glaring hole in this method which I hope someone can spot. (If anyone can even understand me at all) Or maybe I discovered a known method?

Anyway thanks in advance

Pretty much the title. What are the downsides and upsides to using either? What do you guys use and why? I have access to both since my university provides Matlab to us for free.

After struggling to find any good resources / starting points on the topic of thrust vector control on rockets, I have come to r/amateurTVC once again in hopes of any advice and help possible!

Firstly, in order to determine the rocket's attitude from an IMU containing both gyroscopes and accelerometers, some sort of filter is required due to the gyroscpoe's drift and there being no 1g reference for the accelerometers (as the rocket itself is accelerating). From what I understand, a Kalman filter is a potential solution, albeit quite complicated, but is something along the lines of an arduino powerful enough to run a Kalman filter real time anyway? Alternatively there's something called a Madgwick filter which is more computationally efficient; however, it seems to be less precise and less flexible. Which would be more appropriate for a model rocket?

For whichever is the most appropriate, what are some good resources to understand and implement the filter? I have found some books (online pdfs) on the Kalman filter, but I don't know which sections are relevant to the application of attitude estimation of an accelerating rocket. Additionally, from my very basic fundamental understanding; it requires equations of motion that take into account the variation in thrust of the rocket, the resultant torque from each gimbal movement, the drag profile of the rocket, etc... But doesn't this create a "What came first? The chicken or the egg" senario? I need to know the attitude of the rocket to angle the TVC mount accordingly, but to know the attitude I also need to know the angle of the TVC mount?

Thank you for taking the time to read this post / my confusion! Any resources on understanding how best to tacle the problem is much appreciated, I want to put in the work but currently am unsure of which direction to put it in.

Oscar

first try here!

A month ago I read somewhere that the gyroscope should be positioned on the center of gravity of the rocket, but I can't find the article,doing some static tests (me moving the rocket with my hand) it doesn't seem to me that there are big differences but I wouldn't want to screw everything up for a small detail, does anyone know anything about it?

It may seem like a silly question to anyone that has the slightest idea what they're talking about, but I don't have that so I'm asking it anyway!

From what I understand, the problem with using accelerometers in attitude detection is that the acceleration of the rocket interferes with the standard 1g that is used to calculate the absolute angle. Looking around a bit there doesn't seem to be a whole lot on how to get around this (I found one feed but it was a very complicated approach that I barely understood!), so I thought about how I might solve it and it just seems too simple to be true. Hence, I was hoping someone might be able to point out the falt in my thinking!

As the magnitude of the force on the accelerometer's "x", "y" and "z" axes (so pythag....) would be equal to the amount of gs on the rocket, why not just use that calculated value of the acceleration of the rocket as the new standard in that interval of time? As in, say the rocket at one instance in flight exerted a force of 9g on the IMU, to take that 9g as the new 1g and split it into it's components (x, y & z) to find the attitude - along with the gyro data of course.

Thank you for your time if you made it this far!

Oscar

Hey, I'm starting to build my own flight computer from scratch. I've already tried 1 based on teensy and it failed. I want to know about all PCB design and coding and everything required to learn for this project.

Hello,I'm doing my first TVC rocket, any tips? I already finished the software and the rocket is looking pretty good

Hi all, I'm starting to code my flight computer for my TVC rocket. Can anyone give me a general code setup/foundation to code from? I'm looking for something to see how to set up and order my code. e.g Setup -> get IMUº (will need more detail on this) -> run that through PID (I'm not sure how to setup a PID loop) -> take the PID output and put it into the TVC mount.

I will need a bit more detail on how to go around implementing these points, especially the PID math and PID output to gimble, any links or advice would be appreciated :)

Hey all I am part of group putting together a team to experiment with TVC at UoP here in Central Europe and wondering which projects to look into for inspiration.

Already we follow of course the Delta Space Systems, the course of Garrett Gorden and Guido (AeroVector software etc).

hi, I'm new to TVC, and before starting I wanted to ask a few questions:

1. It is correct to say that the difference between Euler angles and rotation angles lies in the fact that the euler angles are expressed in a global reference system while the rotation angles not. In a nutshell, if Y = 0 when pointing up, x = 0 when parallel to the ground and Z = 0 when pointing north, then I'm dealing with euler angles.

2. i tried to write some code to convert euler angles to quaternions, however when i convert them back to euler angles the value does not match if i exceed +/- 90° in the x input value

this is the output i get from python once i run the code:

example 1

input rotation angle x =  -48
input rotation angle y =  15
input rotation angle z =  45
euler angle x =  -47.99999999999999
euler angle y =  14.999999999999998
euler angle z =  44.99999999999999

example 2

input rotation angle y =  89
input rotation angle y =  15
input rotation angle z =  45
euler angle x =  88.99999999999937
euler angle y =  14.999999999999659
euler angle z =  44.999999999999424

example 3 

input rotation angle y =  -91
input rotation angle y =  15
input rotation angle z =  45
euler angle x =  -88.99999999999937
euler angle y =  -165.0000000000001
euler angle z =  -134.99999999999937

i also checked the simulink blocks: https://www.mathworks.com/help/aeroblks/quaternionstorotationangles.html and it seems that also there works in the same way.

is this normal or is it a problem? if it were a problem do you know how to solve it?

3. Is it really necessary to have the angles of rotation in a global frame of reference, I mean, can't I just set the setpoint of the pid with the gyro value recorded just before the rocket takes off? even if the gyro thinks it is pointing somewhere else I don't think it should be a problem, it will be a secret between me and the rocket!

if I don't use a global frame of reference,do you think quaternions can get in my way?

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thanks in advance for any replies.I'll be happy to share the code once it's done

I see a lot of TVC simulators online, and the different ways people have attempted to create their own. My question is: how do these simulators account for movement in both X and Y directions? It seems as though only one dimension is taken care of.

As far as I understand,for a TVC system. I need to take the angular rates of my gyro, convert them into quaternions and convert them to euler angels. These angels go into my PID controller and my PID Controller gives me angels for my tvc mount.

To tune the PID controller, I simulate the torque applied by the tvc mount with the motor thrust curve and the distance from the tvc to the center of mass.Then I divide the torque by the moment of inertia of the rocket to get the angular acceleration. The angular acceleration goes into my pid controller.So that i can add some disturbaned forces and and tune my pid.

My question is wether this is roughly right so that i can start building my program.

We know that joe Barnard started bps and has become a successful business for Joe. At the same time his YouTube has taught and inspired many to replicate what he has achieved. Hence we saw a huge surge of organisations starting in 2019-2020. But right now the current hype of tvc has died down: not much updates from some organisation are even posted. Jus want to get some of your thoughts.

Hello

I am wanting to make a tvc mount.

I am very new to this.

I wanted to ask if any one has any files that are available to make a tvc mount with the flight computer files.

If anyone can help that you

Hi! My friends and I are trying to build a TVC capable model rocket. We were looking into different kind of mounts and were wondering if there’s any paper comparing the various kind and their respective pros and cons (like ones that uses linear actuators vs servo). Any help is deeply appreciated. Thanks in advance!

Has anyone ever seen a TVC mount that fits ~40 mm motors? I’m living in Germany and can only get D9 motors (Diameter 18mm) and thought to use 3 of them at once to get the thrust of a e-f motor. Do you think this will work and where I can get the files for that mount. Thank you I need it for a school project.