Hello,
I have an mpu6050 and i want to measure XYZ angle but you know there is a gimball lock when i rotate pith angle to 90 degree then i rotate roll angle to 90 degree it exposes gives some meaningless angle. So i know that quaternion angles work very well with gimball lock but i want to show the XYZ angle without gimball lock so i try to convert to quaternion angles to euler angles but ı didnt make it. So if anyone can help i am really going to very thankful.
I am using jeff rowberg mpu6050's library
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May i ask what information you need ?
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I read it my question is obvious actually i read many forum question and i saw your many response i also try your library. to sum up, i think you already understand my question. that is why i ask you what information you need it. Because it's not programming question so i dont share any code i already explain question quite detalied. I want to measure angle without gimball lock 0-180 degree for all axis is there a way to do this. One way it comes my mind converting quaternion angles to eular angle does it work ? if it is what is the formulas i try some formulas and didnt work
yaw = atan2(2.0f * (q[1] * q[2] + q[0] * q[3]), q[0] * q[0] + q[1] * q[1] - q[2] * q[2] - q[3] * q[3]);
pitch = -asin(2.0f * (q[1] * q[3] - q[0] * q[2]));
roll = atan2(2.0f * (q[0] * q[1] + q[2] * q[3]), q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]);
pitch *= 180.0f / PI;
yaw *= 180.0f / PI;
yaw -= 13.8f; // Declination at your location
roll *= 180.0f / PI;
Correct.
What you forgot to do was supply any of the information needed to answer the question.
Good luck with your project!
I also ask you to what information you need it so it's up to you
class Quaternion {
public:
float w;
float x;
float y;
float z;
quaternion comes like this in jeff rowberg library.
in your equation there is q[0] q[1] q[2] q[3]
how can i match it q[0] = w, q[1] = x, q[2] = y, q[3] = z maybe like this ?
Yes, it is this mapping.
You can have more informations here:
(Conversion between quaternions and Euler angles - Wikipedia)
my breadboard position like this.
in the picture i show the direction with arrıows with this should be roll angle but in serial monitor when i rotate it changes the pitch angle. this is firt problem.
Second problem is when i rotate this angle to 90 degree even it become 80-90 degree suddenly roll angle become -140 degree.
void loop() {
// if programming failed, don't try to do anything
if (!dmpReady) return;
// read a packet from FIFO
if (mpu.dmpGetCurrentFIFOPacket(fifoBuffer)) { // Get the Latest packet
#ifdef OUTPUT_READABLE_QUATERNION
// display quaternion values in easy matrix form: w x y z
mpu.dmpGetQuaternion(&q, fifoBuffer);
/*
Serial.print("quat\t");
Serial.print(q.w);
Serial.print("\t");
Serial.print(q.x);
Serial.print("\t");
Serial.print(q.y);
Serial.print("\t");
Serial.println(q.z);
*/
yaw = atan2(2.0f * (q.x * q.y + q.w * q.z), q.w * q.w + q.x * q.x - q.y * q.y - q.z * q.z);
pitch = -asin(2.0f * (q.z * q.z - q.w * q.y));
roll = atan2(2.0f * (q.w * q.x + q.y * q.z), q.w * q.w - q.x * q.x - q.y * q.y + q.z * q.z);
// Açıları derece cinsine çevirme
pitch *= 180.0f / PI;
yaw *= 180.0f / PI;
yaw -= 13.8f; // Bulunduğunuz konum için doğrulama (declination) açısı
roll *= 180.0f / PI;
Serial.print("pitch: "); Serial.print(pitch);
Serial.print(" roll: "); Serial.print(roll);
Serial.print(" yaw: "); Serial.println(yaw);
#endif
Does you use this librairy ?
https://forum.arduino.cc/t/finally-mpu6050-fifo-dmp-quaternion-code-for-arduino-made-easy/598424
There is an example with a Yaw,Pitch,Roll conversion made in the librairy.
I try it now ı run Simple_MPU6050_Example skecth but same problem exist
when mpu6050 initial position with(0,0,0) then i roll angle to around the 80 and 90 degree then pitch and yaw become -140_-170 degree sudddenly there is something wrong with me or am i missing something i only rotate roll angle to 90 degree so pitch angle should stay 0 degree am i right ? . I just want to measure 0-180 degree with all axis that is what i want
@nferry
So, it is not a software problem, but an hardware or environment issue.
Somes ideas:
- Is your sensor correctly oriented ?
- Is your sensor not near a metallic environment (Magnetometer) ?
- Is your sensor perturbated by external behaviors ?
- Is your sensor working..... ?
...
Not easy, good luck.
Best regards
I dont think my sensor is broken because i execute jeff rowberg teapot example and i move my mpu6050 around i saw it working really good with quaternion but when i try to get angle ı have an issue which i mention it. Thank you for your help. I hope i can make it. It is important for me
@nferry