# Resources on model Rocket Thrust Vectoring (in particular attitude estimation)

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#### OskysWork

##### New Member
After struggling to find any good resources / starting points on the topic of thrust vector control on rockets, I have come to r/modelrocketry 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

After struggling to find any good resources / starting points on the topic of thrust vector control on rockets, I have come here 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

Do some more searches in this forum as there have been multiple discussion and code posted.

Which Arduino?? Arduino is a board format and there are many different processors available.
Some are multi-core with FPU and running in the 100's MHz. These would keep up with any of the calculations needed.

Sensor sampling rate should be at least 50sps and better at 100-200sps. This will be your first hardware/software challange that also leaves enough processor cycles for processing.

Before going to a VT system build and code an IMU and fly it on a simple rocket.
Log the raw and calculated data to post analyze and compare against sim's of the flight.

Logging Raw data is very useful since you can run this through other processing to try other processing methods without flying again.

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