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I need help understanding the difference from Y/P/R rate and the data that I can get from a gyroscope. I am using the raw readings of my IMU (MPU9250) and the Madwick Filter to calculate a quaternion that represents the orientation of my device, then I can get the Y/P/R angles from it, also I need to get the Y/P/R RATES and this is where my mind gets confused. If my understanding is correct, these are the rate of change of the corresponding angles. A gyroscope can measure rotation around three axes: x, y, and z, right? And they are not the same as the Y/P/R angles. How should I be getting the data I need with using only an IMU?

I'm am really sorry for my badly written explanation, English is not my first language and I'm a software engineer not specialized in this field so it gets even harder to communicate my doubts. Thanks!

LittnerDiAzure
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  • What exactly are you looking for? As in what is the final data output you want Yaw pitch and roll angles? Or an angular velocity (degree/second) ? https://en.wikipedia.org/wiki/Aircraft_principal_axes. Read this to help understand y/p/r – DrMrstheMonarch Jan 08 '20 at 12:49
  • I need them because I want to use this library to get a corrected position of my device. I have every variable the data input requires except the y/p/r rates. Here you can see what are the variables that I need – LittnerDiAzure Jan 08 '20 at 13:07
  • You’re already using the madgwick filter for fusion, why are you using the kalman too? You use one or the other, not botj. – DrMrstheMonarch Jan 08 '20 at 13:09
  • Madgwick does not allow me to correct the longitude and latitude values I get from the GPS, also the speed that I can get processing my IMU values would not be correct at all (I calculate it integrating an acceleration vector). I would like to fuse the IMU data and the GPS data to get a better estimated position – LittnerDiAzure Jan 08 '20 at 13:11
  • Thats fine, but why are using both? The kalman filter does all the fusing itself, you dont fuse it first via madgwick then pass it to the kalman....you just give thr kalman the data it wants, namely your 9dof data – DrMrstheMonarch Jan 08 '20 at 13:15
  • Oh sorry, I was using a madgwick filter because I tried another aproach of the kalman filter that needed the east and north accelerations, and I calculated them using quaternions, this one does not need it. My 9dof data does not have the y/p/r rates, or is there something I am not understanding? – LittnerDiAzure Jan 08 '20 at 13:23
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    Does this answer your question? Euler Angles from 9DOF IMU – 50k4 Jan 10 '20 at 10:13

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