@btrueblood ==> yup, reared the sentences and understood your point. I'll try to make a controller that will attempt to keep theta-dot small and report back my results.
... And here is the PDF of the non-linear dynamic equations.http://files.engineering.com/getfile.aspx?folder=76903691-e355-4812-8265-8f5972a6a897&file=Nonlinear_dynamics_equations.pdf
Oops, seems I can only upload 1 file at a time, so here goes the second MATLAB file.http://files.engineering.com/getfile.aspx?folder=e136220c-8c8a-4283-a25a-e884b5ddd969&file=sixDOF_rocket_dynamics_wDrag.m
Hello,
So I've re-written the dynamic equations and simulated them in MATLAB. I attached a PDF of the equations as well as the 2 Matlab files you need to run the simulation. They seem to work well, but disclaimer : this is work in progress!
Now comes the linearization step, which I will report...
@btrueblood Thanks a lot for the information and explanation. Could you please clarify what you said here:
I don't quite understand what you mean after the "given the assumption that theta-dot..." as it seems to me like that very assumption is what would ensure that the control system works...
@btrueblood Thanks for the info, will look into it. Roll control for boosters is crucial as I imagine that the structure of these cannot tolerate the high aerodynamic loads induced by a roll rate at supersonic velocities (you can see this in the Little Joe video in my last post, the rocket ends...
@GregLocock I see exactly what you are trying to say. My problem is though that the linearized equations must be obtained by Taylor first-order expansion around an "equilibrium point". For pitch and yaw, this equilibrium point is 0 pitch angle (θ), 0 pitch rate (Q), 0 yaw angle (ψ), 0 yaw rate...
I'll have an accelerometer (BMA180 probably) and an IMU. I'm a mechanical engineering student; I have no experience in sensors and I have some experience in control. I'm doing the GNC algorithm for the rocket. If you are experienced, I would really appreciate help regarding how pitch and yaw...
Not at all. The model rocket is conventional (not resembling an RC airplane) and will have automatic control via an on-board micro-controller. My issue is with linearizing the non-linear set of equations when the rocket is free-spinning (free-rolling...). Since it is free to roll, there is no...
I agree. However, imagine this situation. The rocket has a certain spin when a set of fins adjusting pitch are actuated. At time t, the corrective force created by these fins points in one direction. But, since the rocket is rolling (let's assume its roll rate is much faster than the "speed of...
Hello,
I'm designing a controller for rocket Pitch and Yaw control (aim is for rocket to remain upright, so zero pitch and yaw angles). I'm having trouble developing the dynamic equations and can't find existing material corresponding to my needs elsewhere. I've got the following non-linear...
Hello,
I'm designing a controller for rocket Pitch and Yaw control (aim is for rocket to remain upright, so zero pitch and yaw angles). I'm having trouble developing the dynamic equations and can't find existing material corresponding to my needs elsewhere. I've got the following non-linear...
