Unstable gravity vector

[cleaf30]

I am using a freeIMU to capture dynamic acceleration but I getting some weird data. below is output with the IMU sitting still. The g(x,y,z) start off fine then all the sudden their is a drastic change(labeled below). The raw values all seem pretty consistent so I'd imagine it has something to do with the algorithm. The code I'm using to get g(x,y,z) is the same as whats given as a help function at the bottom of freeIMU.cpp

g[0] = 2 * (q[1] * q[3] - q[0] * q[2]); g[1] = 2 * (q[0] * q[1] + q[2] * q[3]); g[2] = q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]; G = sqrt(g[0] * g[0] + g[1] * g[1] + g[2] * g[2]);

gx	gy	gz	G(magnitude)	raw[0]	raw[1]	raw[2]	raw[3]	raw[4]	raw[5]	raw[6]	raw[7]	raw[8]	temp	pressure
0.04	0.00	1.00	1.00	226	116	17304	-44	17	-12	-78	123	-606	0.00,	0.00,
0.05	-0.00	1.00	1.00	172	134	17312	-45	17	-13	-82	125	-607	27.06,	0.00,
0.05	-0.00	1.00	1.00	190	138	17258	-44	18	-13	-78	123	-608	27.06,	1008.03,
0.05	-0.01	1.00	1.00	206	100	17314	-43	18	-13	-79	124	-607	27.08,	1008.08,
0.06	-0.01	1.00	1.00	198	118	17296	-44	18	-14	-79	123	-606	27.08,	1008.04,
0.06	-0.01	1.00	1.00	202	88	17276	-45	18	-13	-78	124	-610	27.09,	1008.05,
0.07	-0.01	1.00	1.00	210	120	17278	-45	18	-12	-79	125	-610	27.09,	1008.03,
0.07	-0.02	1.00	1.00	188	108	17266	-44	17	-13	-78	121	-608	27.08,	1008.02,
0.07	-0.02	1.00	1.00	222	168	17300	-45	18	-13	-80	123	-605	27.08,	1008.02,
0.08	-0.02	1.00	1.00	190	136	17362	-44	17	-12	-79	125	-605	27.09,	1008.04,
0.08	-0.03	1.00	1.00	218	74	17272	-45	18	-13	-76	122	-606	27.09,	1008.05,
0.08	-0.03	1.00	1.00	202	132	17292	-45	19	-12	-79	125	-603	27.09,	1008.04,
0.09	-0.03	1.00	1.00	166	118	17324	-45	18	-13	-77	124	-605	27.09,	1008.01,
-0.90	-0.01	-0.44	1.00	218	144	17328	-44	18	-13	-78	121	-604	27.09,	1008.01,
-0.90	-0.01	-0.43	1.00	208	134	17292	-44	18	-12	-79	124	-611	27.09,	1008.00,
-0.90	-0.01	-0.44	1.00	190	144	17292	-44	18	-13	-77	123	-603	27.09,	1008.01,
-0.90	-0.01	-0.44	1.00	212	120	17230	-44	18	-13	-78	122	-608	27.09,	1008.07,
-0.90	-0.01	-0.44	1.00	226	104	17322	-45	18	-13	-77	124	-607	27.09,	1008.07,
-0.90	-0.01	-0.44	1.00	196	92	17292	-44	18	-13	-78	123	-601	27.09,	1008.04,
-0.89	-0.01	-0.45	1.00	196	104	17266	-45	18	-12	-78	122	-605	27.09,	1008.06,
-0.89	-0.01	-0.45	1.00	190	86	17300	-44	18	-13	-80	124	-605	27.09,	1008.01,
-0.90	-0.01	-0.44	1.00	212	114	17254	-45	18	-12	-79	123	-608	27.09,	1008.00,
-0.90	-0.01	-0.44	1.00	212	154	17266	-44	18	-12	-79	124	-603	27.09,	1007.99,
-0.90	-0.01	-0.44	1.00	174	116	17314	-44	18	-12	-77	123	-608	27.09,	1007.99,
-0.90	-0.01	-0.44	1.00	184	108	17280	-44	18	-12	-81	125	-603	27.09,	1008.04,
-0.90	-0.01	-0.44	1.00	198	102	17318	-44	18	-13	-74	121	-607	27.09,	1008.04,
-0.89	-0.01	-0.46	1.00	196	74	17302	-44	18	-12	-79	123	-609	27.09,	1008.07,
-0.90	-0.01	-0.44	1.00	178	100	17320	-45	18	-12	-78	125	-606	27.08,	1008.05,
-0.89	-0.01	-0.45	1.00	200	142	17378	-45	18	-12	-77	124	-609	27.08,	1008.04,
-0.90	-0.01	-0.44	1.00	198	62	17306	-44	18	-13	-79	125	-607	27.08,	1008.05,
-0.89	-0.01	-0.45	1.00	186	138	17306	-45	17	-13	-78	123	-609	27.08,	1008.03,
-0.90	-0.01	-0.44	1.00	206	110	17304	-44	18	-13	-76	126	-604	27.08,	1008.01,
-0.89	-0.01	-0.45	1.00	148	144	17284	-44	17	-13	-78	125	-606	27.08,	1007.99,

I noticed in the hookup guide it has the mega connected directly to the IMU. I've read about having to put in a level shifter to hook it up to the mega due to 5V pull ups. So I currently have a level shifter on the SDA, SCL lines set at 3.3V on the low side coming off the IMU's 3.3V pin and 5V on the high side coming off the mega. Is this necessary could it be causing me problems?

Also before experiencing this issue with my gravity vector I had a problem with the settling time for accelerations being way too long 10+ seconds. Any idea why this was happening or what I could do? And yes I have calibrated my IMU.

Thanks, Cody

[mjs513]

Hi Cody,

When you say you are using a freeimu are you actually using a FreeIMU v4 board or some other board? Also, which algorithm option are you using (set in FreeIMU.h): Marg = 0, 1,3,or 4? The reason I ask is I can try and isolate the problem and hookup the equivalent board that I have. I am also assuming you set the board configuration in the FreeIMU.h file as well. One issue some folks had is they uncommented the board they have but forgot to comment out the one that is already uncommented.

The data does look very strange when compared to the accelerations. Look at those its telling me that you have the board steady but the vector directions changed.

As for the settling times you can tweak the gains that I have set as defaults for the different configurations to improve the converge time.

As for the level shifters that should not be an issue as I did that when hooking up to a Teensy. Also, looking at some of Fabio's hookup guides he has it hooked directly to the +5v (vdd) and direct to the scl/scd lines.

Mike

[mjs513]

Guess you resolved you problem - what was the issue.

[cleaf30]

No I haven't resolved it I just tried to edit a sentence and ended up making a new issue. I don't know how to delete an issue so I closed it. Yes I have a v4r3. I'm currently using a marg = 3. I have the correct board uncommented.

[mjs513]

Ok thanks this way I can hook mine up. Can you post the sketch you used, will save me some time. Probably will look at it tonight, If you have the version with DCM incorporated give Marg = 4 a try and see if you get the same thing. As for the tweaking of the gains, that should help with your other probably with settling time. This was actually discussed in one of the other issues if you go rummaging around.

[cleaf30]

I've just tried with marg = 0, 1, 3, and 4 and got similar results. Although I'm not sure if I have the DCM version, there wasn't anything in the comment about marg = 4 but it compiled. I downloaded the FreeIMU library a month or so ago.

here's my sketch. thank for the help.

#include <HMC58X3.h>
#include <MS561101BA.h>
#include <I2Cdev.h>
#include <MPU60X0.h>
#include <EEPROM.h>
#include <AP_Baro_MS5611.h>
#include "RunningAverage.h"
#include <iCompass.h>

#include <BMP085.h>

#include <AP_Math_freeimu.h>
#include <Filter.h>    // Filter library
#include <Butter.h>    // Butterworth filter

#include <EEPROM.h>
#include <Wire.h>
#include <SPI.h>

//#define DEBUG
#include "DebugUtils.h"
#include "CommunicationUtils.h"
#include "FreeIMU.h"
#include "FilteringScheme.h"
#include <MovingAvarageFilter.h>

float q[4], val[11];
int raw_values[11];
char str[512];

float g[3],G;//gravity
int S;   //conversion factor to g's??
float rx, ry, rz, R;//raw acc
float cx, cy, cz, C; //dynamic acc
float dx, dy, dz, dynamAccelXY;//dynamic accleration in XY(horizontal) plane

// Set the FreeIMU object
FreeIMU my3IMU = FreeIMU();

//my3IMU.setTempCalib(0); // 0 - turn temp calibration off
void setup() {
  Serial.begin(115200);
  Wire.begin();

  delay(5);
  my3IMU.init();
  delay(5);

  S = 16384;
}

void loop() { 
  my3IMU.getQ(q,val);
  my3IMU.getRawValues(raw_values);

  //calibrated
  rx = val[0];
  ry = val[1];
  rz = val[2];

  R = sqrt(rx*rx + ry*ry + rz*rz);

  g[0] = 2 * (q[1] * q[3] - q[0] * q[2]);
  g[1] = 2 * (q[0] * q[1] + q[2] * q[3]);
  g[2] = q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3];
  G = sqrt(g[0]*g[0] + g[1]*g[1] + g[2]*g[2]);

  //dymanic acceleration: accel values - gravity
  cx = rx - g[0];
  cy = ry - g[1];
  cz = rz - g[2];
  C = sqrt(cx*cx + cy*cy + cz*cz);

  //dynamic accel in xy plane (horizontal)
  //cross product of dynamic accel vector and orientation unit vector
   dx = (g[1]*cz - g[2]*cy);
   dy = -(g[2]*cx - g[0]*cz);
   dz = (g[0]*cy - g[1]*cx);
   dynamAccelXY = sqrt(dx*dx + dy*dy + dz*dz);

  Serial.print(g[0]);
  Serial.print("\t");
  Serial.print(g[1]);
  Serial.print("\t");
  Serial.print(g[2]);
  Serial.print("\t\t");
  Serial.print(G);
  Serial.print("\t\t");
//  //Raw
//  Serial.print(rx);
//  Serial.print("\t");
//  Serial.print(ry);
//  Serial.print("\t");
//  Serial.print(rz);
//  Serial.print("\t\t");
//  Serial.print(R);
//  Serial.print("\t\t");
//  //Dynamic  
//  Serial.print(cx);
//  Serial.print("\t");
//  Serial.print(cy);
//  Serial.print("\t");
//  Serial.print(cz);
//  Serial.print("\t\t");
//  Serial.print(C);
//  //Dynamic XY
//  Serial.print("\t\t");
//  Serial.print(dynamAccelXY);
//  Serial.print("\t");
  sprintf(str, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t", raw_values[0], raw_values[1], raw_values[2], raw_values[3], raw_values[4], raw_values[5], raw_values[6], raw_values[7], raw_values[8]);
  Serial.print(str);
  Serial.print(my3IMU.getBaroTemperature()); Serial.print(",");
  Serial.print(my3IMU.getBaroPressure()); Serial.print(",");
  Serial.println("");
  delay(20);

}

[mjs513]

Thanks. The addition of the DCM for Marg = 4 was just posted Thursday.

From: cleaf30 [mailto:notifications@github.com] Sent: Saturday, March 28, 2015 3:10 PM To: mjs513/FreeIMU-Updates Cc: Mike S Subject: Re: [FreeIMU-Updates] Unstable gravity vector (#25)

I've just tried with marg = 0, 1, 3, and 4 and got similar results. Although I'm not sure if I have the DCM version, there wasn't anything in the comment about marg = 4 but it compiled. I downloaded the FreeIMU library a month or so ago.

here's my sketch. thank for the help.

include

include

include

include

include

include

include "RunningAverage.h"

include

include

include

include // Filter library

include // Butterworth filter

include

include

include

//#define DEBUG

include "DebugUtils.h"

include "CommunicationUtils.h"

include "FreeIMU.h"

include "FilteringScheme.h"

include

float q[4], val[11]; int raw_values[11]; char str[512];

float g[3],G;//gravity int S; //conversion factor to g's?? float rx, ry, rz, R;//raw acc float cx, cy, cz, C; //dynamic acc float dx, dy, dz, dynamAccelXY;//dynamic accleration in XY(horizontal) plane

// Set the FreeIMU object FreeIMU my3IMU = FreeIMU();

//my3IMU.setTempCalib(0); // 0 - turn temp calibration off void setup() { Serial.begin(115200); Wire.begin();

delay(5); my3IMU.init(); delay(5);

S = 16384; }

void loop() { my3IMU.getQ(q,val); my3IMU.getRawValues(raw_values);

//calibrated rx = val[0]; ry = val[1]; rz = val[2];

R = sqrt(rxrx + ryry + rz*rz);

g[0] = 2 * (q[1] * q[3] - q[0] * q[2]); g[1] = 2 * (q[0] * q[1] + q[2] * q[3]); g[2] = q[0] * q[0] - q[1] * q[1] - q[2] * q[2] + q[3] * q[3]; G = sqrt(g[0]g[0] + g[1]g[1] + g[2]*g[2]);

//dymanic acceleration: accel values - gravity cx = rx - g[0]; cy = ry - g[1]; cz = rz - g[2]; C = sqrt(cxcx + cycy + cz*cz);

//dynamic accel in xy plane (horizontal) //cross product of dynamic accel vector and orientation unit vector dx = (g[1]cz - g[2]cy); dy = -(g[2]cx - g[0]cz); dz = (g[0]cy - g[1]cx); dynamAccelXY = sqrt(dxdx + dydy + dz*dz);

Serial.print(g[0]); Serial.print("\t"); Serial.print(g[1]); Serial.print("\t"); Serial.print(g[2]); Serial.print("\t\t"); Serial.print(G); Serial.print("\t\t"); // //Raw // Serial.print(rx); // Serial.print("\t"); // Serial.print(ry); // Serial.print("\t"); // Serial.print(rz); // Serial.print("\t\t"); // Serial.print(R); // Serial.print("\t\t"); // //Dynamic

// Serial.print(cx); // Serial.print("\t"); // Serial.print(cy); // Serial.print("\t"); // Serial.print(cz); // Serial.print("\t\t"); // Serial.print(C); // //Dynamic XY // Serial.print("\t\t"); // Serial.print(dynamAccelXY); // Serial.print("\t"); sprintf(str, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t", raw_values[0], raw_values[1], raw_values[2], raw_values[3], raw_values[4], raw_values[5], raw_values[6], raw_values[7], raw_values[8]); Serial.print(str); Serial.print(my3IMU.getBaroTemperature()); Serial.print(","); Serial.print(my3IMU.getBaroPressure()); Serial.print(","); Serial.println(""); delay(20);

}

— Reply to this email directly or view it on GitHub https://github.com/mjs513/FreeIMU-Updates/issues/25#issuecomment-87286077 . https://github.com/notifications/beacon/AFHhxQCUv-gUVY3tht4caGv7XR1wrU2Dks5n5vPqgaJpZM4D2ZCz.gif

[cleaf30]

I just tried it with DCM and got similar results. It stabilizes after the drastic change. Could it be resetting itself?

gx	gy	gz	G	raw[0]	raw[1]	raw[2]	raw[3]	raw[4]	raw[5]	raw[6]	raw[7]	raw[8]	temp	pressure
0.00	0.00	0.00	0.00	362	354	17412	-42	17	-13	-33	20	-605	0.00,	0.00,
0.00	-0.00	0.00	0.00	368	370	17340	-43	17	-13	-31	21	-606	25.10,	0.00,
0.00	-0.00	0.00	0.00	390	342	17342	-42	17	-13	-35	20	-603	25.10,	1007.12,
0.00	0.00	1.01	1.01	394	384	17356	-43	17	-13	-37	22	-603	25.15,	1007.24,
0.00	0.00	1.02	1.02	360	358	17356	-42	17	-13	-37	23	-602	25.15,	1007.14,
0.00	0.01	1.03	1.03	364	352	17366	-43	17	-13	-32	20	-602	25.18,	1007.23,
0.00	0.01	1.04	1.04	410	358	17332	-42	17	-14	-35	23	-608	25.18,	1007.15,
0.00	0.01	1.05	1.05	370	382	17356	-42	17	-14	-34	20	-605	25.21,	1007.20,
0.00	0.01	1.07	1.07	328	360	17330	-42	17	-12	-36	20	-605	25.21,	1007.08,
0.00	0.01	1.09	1.09	360	362	17362	-42	17	-13	-35	20	-606	25.22,	1007.12,
0.00	0.01	1.11	1.11	392	370	17342	-42	18	-13	-34	20	-602	25.22,	1007.10,
0.00	0.01	1.13	1.13	396	330	17328	-42	17	-12	-36	20	-605	25.24,	1007.14,
0.00	0.01	1.15	1.15	336	344	17350	-42	17	-13	-32	20	-598	25.24,	1007.14,
-0.88	-0.02	-0.47	1.00	372	346	17388	-42	17	-14	-35	22	-606	25.25,	1007.17,
-0.90	-0.02	-0.44	1.00	360	370	17384	-42	16	-12	-37	19	-606	25.25,	1007.16,
-0.89	-0.02	-0.45	1.00	386	370	17342	-42	17	-13	-35	21	-605	25.25,	1007.16,
-0.89	-0.02	-0.45	1.00	378	308	17408	-43	18	-12	-34	19	-608	25.25,	1007.16,
-0.89	-0.02	-0.46	1.00	348	338	17330	-42	17	-13	-32	20	-604	25.27,	1007.19,
-0.89	-0.02	-0.45	1.00	376	340	17342	-42	17	-13	-35	20	-604	25.27,	1007.12,
-0.90	-0.03	-0.44	1.00	366	350	17364	-43	18	-13	-35	20	-604	25.27,	1007.13,
-0.89	-0.02	-0.45	1.00	374	380	17310	-42	17	-13	-34	20	-600	25.27,	1007.20,
-0.90	-0.02	-0.43	1.00	370	354	17374	-42	17	-13	-36	22	-600	25.28,	1007.21,
-0.90	-0.02	-0.43	1.00	364	372	17382	-42	17	-13	-34	20	-604	25.28,	1007.18,
-0.90	-0.02	-0.43	1.00	364	350	17366	-42	17	-13	-35	22	-603	25.28,	1007.17,
-0.90	-0.02	-0.44	1.00	380	380	17356	-42	17	-13	-37	20	-606	25.28,	1007.17,
-0.89	-0.02	-0.45	1.00	394	384	17318	-41	18	-13	-34	20	-605	25.28,	1007.18,
-0.89	-0.02	-0.45	1.00	380	380	17378	-42	17	-13	-34	23	-607	25.28,	1007.21,
-0.89	-0.02	-0.46	1.00	404	366	17408	-42	17	-13	-34	21	-605	25.28,	1007.20,
-0.89	-0.02	-0.45	1.00	422	364	17322	-42	17	-13	-33	22	-599	25.28,	1007.18,
-0.90	-0.02	-0.43	1.00	368	370	17340	-42	17	-13	-34	19	-606	25.29,	1007.19,
-0.89	-0.02	-0.46	1.00	380	348	17350	-42	17	-13	-33	23	-598	25.29,	1007.11,
-0.89	-0.02	-0.45	1.00	400	362	17324	-42	16	-14	-35	23	-605	25.29,	1007.12,
-0.90	-0.02	-0.44	1.00	390	378	17348	-42	17	-13	-33	21	-604	25.29,	1007.19,
-0.90	-0.02	-0.44	1.00	356	338	17312	-42	17	-13	-35	21	-605	25.29,	1007.19,
-0.88	-0.02	-0.47	1.00	346	336	17350	-42	17	-13	-37	22	-605	25.29,	1007.14,

[mjs513]

The answer to your question is yes. It takes a minute or so to the MPU6050 to stabilize once you start it up. If you read the stuff out there they all say you have to keep the imu steady during its startup period – this is pretty much everytime you rerun the sketch. The algorithm also takes a little while to converge from their starting conditions.

What I am curious about is the gravity vector itself why GZ isn’t larger than it is. It looks like the board is titled. Whaa

From: cleaf30 [mailto:notifications@github.com] Sent: Saturday, March 28, 2015 3:56 PM To: mjs513/FreeIMU-Updates Cc: Mike S Subject: Re: [FreeIMU-Updates] Unstable gravity vector (#25)

I just tried it with DCM and got similar results. It stabilizes after the drastic change. Could it be resetting itself?

gx

gy

gz

G

raw[0]

raw[1]

raw[2]

raw[3]

raw[4]

raw[5]

raw[6]

raw[7]

raw[8]

temp

pressure

0.00

0.00

0.00

0.00

362

354

17412

-42

17

-13

-33

20

-605

0.00,

0.00,

0.00

-0.00

0.00

0.00

368

370

17340

-43

17

-13

-31

21

-606

25.10,

0.00,

0.00

-0.00

0.00

0.00

390

342

17342

-42

17

-13

-35

20

-603

25.10,

1007.12,

0.00

0.00

1.01

1.01

394

384

17356

-43

17

-13

-37

22

-603

25.15,

1007.24,

0.00

0.00

1.02

1.02

360

358

17356

-42

17

-13

-37

23

-602

25.15,

1007.14,

0.00

0.01

1.03

1.03

364

352

17366

-43

17

-13

-32

20

-602

25.18,

1007.23,

0.00

0.01

1.04

1.04

410

358

17332

-42

17

-14

-35

23

-608

25.18,

1007.15,

0.00

0.01

1.05

1.05

370

382

17356

-42

17

-14

-34

20

-605

25.21,

1007.20,

0.00

0.01

1.07

1.07

328

360

17330

-42

17

-12

-36

20

-605

25.21,

1007.08,

0.00

0.01

1.09

1.09

360

362

17362

-42

17

-13

-35

20

-606

25.22,

1007.12,

0.00

0.01

1.11

1.11

392

370

17342

-42

18

-13

-34

20

-602

25.22,

1007.10,

0.00

0.01

1.13

1.13

396

330

17328

-42

17

-12

-36

20

-605

25.24,

1007.14,

0.00

0.01

1.15

1.15

336

344

17350

-42

17

-13

-32

20

-598

25.24,

1007.14,

-0.88

-0.02

-0.47

1.00

372

346

17388

-42

17

-14

-35

22

-606

25.25,

1007.17,

-0.90

-0.02

-0.44

1.00

360

370

17384

-42

16

-12

-37

19

-606

25.25,

1007.16,

-0.89

-0.02

-0.45

1.00

386

370

17342

-42

17

-13

-35

21

-605

25.25,

1007.16,

-0.89

-0.02

-0.45

1.00

378

308

17408

-43

18

-12

-34

19

-608

25.25,

1007.16,

-0.89

-0.02

-0.46

1.00

348

338

17330

-42

17

-13

-32

20

-604

25.27,

1007.19,

-0.89

-0.02

-0.45

1.00

376

340

17342

-42

17

-13

-35

20

-604

25.27,

1007.12,

-0.90

-0.03

-0.44

1.00

366

350

17364

-43

18

-13

-35

20

-604

25.27,

1007.13,

-0.89

-0.02

-0.45

1.00

374

380

17310

-42

17

-13

-34

20

-600

25.27,

1007.20,

-0.90

-0.02

-0.43

1.00

370

354

17374

-42

17

-13

-36

22

-600

25.28,

1007.21,

-0.90

-0.02

-0.43

1.00

364

372

17382

-42

17

-13

-34

20

-604

25.28,

1007.18,

-0.90

-0.02

-0.43

1.00

364

350

17366

-42

17

-13

-35

22

-603

25.28,

1007.17,

-0.90

-0.02

-0.44

1.00

380

380

17356

-42

17

-13

-37

20

-606

25.28,

1007.17,

-0.89

-0.02

-0.45

1.00

394

384

17318

-41

18

-13

-34

20

-605

25.28,

1007.18,

-0.89

-0.02

-0.45

1.00

380

380

17378

-42

17

-13

-34

23

-607

25.28,

1007.21,

-0.89

-0.02

-0.46

1.00

404

366

17408

-42

17

-13

-34

21

-605

25.28,

1007.20,

-0.89

-0.02

-0.45

1.00

422

364

17322

-42

17

-13

-33

22

-599

25.28,

1007.18,

-0.90

-0.02

-0.43

1.00

368

370

17340

-42

17

-13

-34

19

-606

25.29,

1007.19,

-0.89

-0.02

-0.46

1.00

380

348

17350

-42

17

-13

-33

23

-598

25.29,

1007.11,

-0.89

-0.02

-0.45

1.00

400

362

17324

-42

16

-14

-35

23

-605

25.29,

1007.12,

-0.90

-0.02

-0.44

1.00

390

378

17348

-42

17

-13

-33

21

-604

25.29,

1007.19,

-0.90

-0.02

-0.44

1.00

356

338

17312

-42

17

-13

-35

21

-605

25.29,

1007.19,

-0.88

-0.02

-0.47

1.00

346

336

17350

-42

17

-13

-37

22

-605

25.29,

1007.14,

— Reply to this email directly or view it on GitHub https://github.com/mjs513/FreeIMU-Updates/issues/25#issuecomment-87292146 . https://github.com/notifications/beacon/AFHhxbdOUDa5VgU5swLa3Pcsk-QhslUyks5n5v7agaJpZM4D2ZCz.gif

[mjs513]

Here is what I am getting – by the way where you located (by any chance are you closer to the equator) – I am in NY:

0.00 -0.00 -0.00 0.00 624 78 16538 -39 8 -19 159 -258 -496 29.60,1009.74,

0.00 -0.00 -0.00 0.00 610 130 16506 -39 7 -16 160 -259 -497 29.60,1009.74,

0.00 -0.00 -0.00 0.00 618 110 16554 -40 7 -15 163 -259 -498 29.60,1009.73,

0.05 0.00 1.00 1.00 624 136 16540 -39 7 -15 161 -260 -497 29.60,1009.74,

0.05 0.00 1.00 1.00 600 128 16510 -40 8 -15 162 -256 -500 29.70,1009.73,

0.05 0.00 1.00 1.00 622 110 16510 -39 8 -15 162 -256 -499 29.70,1009.74,

0.05 0.01 1.00 1.00 602 124 16502 -39 8 -16 158 -256 -495 29.70,1009.77,

0.05 0.01 1.00 1.00 610 114 16540 -39 7 -16 159 -257 -496 29.70,1009.81,

0.05 0.01 1.00 1.00 618 86 16520 -39 7 -16 159 -256 -499 29.70,1009.77,

0.05 0.01 1.00 1.00 618 104 16518 -38 7 -16 157 -257 -496 29.70,1009.76,

0.05 0.01 1.00 1.00 602 70 16546 -39 7 -16 160 -259 -496 29.70,1009.84,

0.05 0.01 1.00 1.00 622 138 16538 -39 8 -15 159 -258 -499 29.70,1009.76,

0.05 0.01 1.00 1.00 622 106 16560 -39 7 -15 161 -260 -500 29.70,1009.78,

0.76 0.00 0.65 1.00 606 140 16546 -39 7 -16 158 -256 -498 29.70,1009.78,

0.76 0.00 0.65 1.00 592 114 16518 -39 7 -16 159 -255 -497 29.70,1009.84,

0.76 0.00 0.65 1.00 588 146 16538 -40 8 -15 163 -258 -494 29.70,1009.68,

0.76 0.00 0.64 1.00 586 136 16562 -40 8 -15 161 -256 -498 29.70,1009.77,

0.76 0.00 0.65 1.00 614 116 16504 -39 7 -15 159 -256 -498 29.70,1009.74,

0.77 0.00 0.64 1.00 612 88 16580 -39 8 -16 160 -259 -496 29.70,1009.78,

0.76 0.00 0.65 1.00 584 136 16548 -40 8 -15 163 -257 -497 29.70,1009.78,

0.76 0.00 0.65 1.00 588 166 16496 -40 7 -15 159 -260 -499 29.70,1009.76,

0.76 0.00 0.65 1.00 602 100 16510 -39 7 -16 160 -260 -498 29.70,1009.80,

0.76 0.00 0.65 1.00 626 122 16500 -40 7 -16 160 -256 -500 29.70,1009.81,

0.77 0.00 0.64 1.00 586 124 16530 -39 7 -16 158 -255 -498 29.70,1009.73,

0.77 0.00 0.64 1.00 618 108 16534 -39 7 -15 158 -256 -497 29.70,1009.83,

0.76 0.00 0.64 1.00 598 112 16600 -40 7 -16 164 -256 -494 29.70,1009.68,

0.75 0.00 0.66 1.00 630 142 16554 -39 7 -16 159 -256 -497 29.70,1009.74,

0.76 0.00 0.65 1.00 632 112 16548 -40 8 -16 161 -259 -499 29.70,1009.76,

0.77 0.00 0.64 1.00 600 126 16542 -40 8 -15 161 -258 -499 29.70,1009.76,

0.76 0.00 0.65 1.00 614 96 16524 -39 7 -15 158 -253 -501 29.70,1009.76,

0.76 0.00 0.64 1.00 616 100 16512 -40 7 -15 159 -254 -499 29.70,1009.81,

0.77 0.00 0.64 1.00 624 90 16530 -40 7 -16 159 -257 -494 29.70,1009.68,

0.76 0.00 0.65 1.00 616 124 16518 -39 8 -15 158 -254 -499 29.70,1009.74,

From: cleaf30 [mailto:notifications@github.com] Sent: Saturday, March 28, 2015 3:56 PM To: mjs513/FreeIMU-Updates Cc: Mike S Subject: Re: [FreeIMU-Updates] Unstable gravity vector (#25)

I just tried it with DCM and got similar results. It stabilizes after the drastic change. Could it be resetting itself?

gx

gy

gz

G

raw[0]

raw[1]

raw[2]

raw[3]

raw[4]

raw[5]

raw[6]

raw[7]

raw[8]

temp

pressure

0.00

0.00

0.00

0.00

362

354

17412

-42

17

-13

-33

20

-605

0.00,

0.00,

0.00

-0.00

0.00

0.00

368

370

17340

-43

17

-13

-31

21

-606

25.10,

0.00,

0.00

-0.00

0.00

0.00

390

342

17342

-42

17

-13

-35

20

-603

25.10,

1007.12,

0.00

0.00

1.01

1.01

394

384

17356

-43

17

-13

-37

22

-603

25.15,

1007.24,

0.00

0.00

1.02

1.02

360

358

17356

-42

17

-13

-37

23

-602

25.15,

1007.14,

0.00

0.01

1.03

1.03

364

352

17366

-43

17

-13

-32

20

-602

25.18,

1007.23,

0.00

0.01

1.04

1.04

410

358

17332

-42

17

-14

-35

23

-608

25.18,

1007.15,

0.00

0.01

1.05

1.05

370

382

17356

-42

17

-14

-34

20

-605

25.21,

1007.20,

0.00

0.01

1.07

1.07

328

360

17330

-42

17

-12

-36

20

-605

25.21,

1007.08,

0.00

0.01

1.09

1.09

360

362

17362

-42

17

-13

-35

20

-606

25.22,

1007.12,

0.00

0.01

1.11

1.11

392

370

17342

-42

18

-13

-34

20

-602

25.22,

1007.10,

0.00

0.01

1.13

1.13

396

330

17328

-42

17

-12

-36

20

-605

25.24,

1007.14,

0.00

0.01

1.15

1.15

336

344

17350

-42

17

-13

-32

20

-598

25.24,

1007.14,

-0.88

-0.02

-0.47

1.00

372

346

17388

-42

17

-14

-35

22

-606

25.25,

1007.17,

-0.90

-0.02

-0.44

1.00

360

370

17384

-42

16

-12

-37

19

-606

25.25,

1007.16,

-0.89

-0.02

-0.45

1.00

386

370

17342

-42

17

-13

-35

21

-605

25.25,

1007.16,

-0.89

-0.02

-0.45

1.00

378

308

17408

-43

18

-12

-34

19

-608

25.25,

1007.16,

-0.89

-0.02

-0.46

1.00

348

338

17330

-42

17

-13

-32

20

-604

25.27,

1007.19,

-0.89

-0.02

-0.45

1.00

376

340

17342

-42

17

-13

-35

20

-604

25.27,

1007.12,

-0.90

-0.03

-0.44

1.00

366

350

17364

-43

18

-13

-35

20

-604

25.27,

1007.13,

-0.89

-0.02

-0.45

1.00

374

380

17310

-42

17

-13

-34

20

-600

25.27,

1007.20,

-0.90

-0.02

-0.43

1.00

370

354

17374

-42

17

-13

-36

22

-600

25.28,

1007.21,

-0.90

-0.02

-0.43

1.00

364

372

17382

-42

17

-13

-34

20

-604

25.28,

1007.18,

-0.90

-0.02

-0.43

1.00

364

350

17366

-42

17

-13

-35

22

-603

25.28,

1007.17,

-0.90

-0.02

-0.44

1.00

380

380

17356

-42

17

-13

-37

20

-606

25.28,

1007.17,

-0.89

-0.02

-0.45

1.00

394

384

17318

-41

18

-13

-34

20

-605

25.28,

1007.18,

-0.89

-0.02

-0.45

1.00

380

380

17378

-42

17

-13

-34

23

-607

25.28,

1007.21,

-0.89

-0.02

-0.46

1.00

404

366

17408

-42

17

-13

-34

21

-605

25.28,

1007.20,

-0.89

-0.02

-0.45

1.00

422

364

17322

-42

17

-13

-33

22

-599

25.28,

1007.18,

-0.90

-0.02

-0.43

1.00

368

370

17340

-42

17

-13

-34

19

-606

25.29,

1007.19,

-0.89

-0.02

-0.46

1.00

380

348

17350

-42

17

-13

-33

23

-598

25.29,

1007.11,

-0.89

-0.02

-0.45

1.00

400

362

17324

-42

16

-14

-35

23

-605

25.29,

1007.12,

-0.90

-0.02

-0.44

1.00

390

378

17348

-42

17

-13

-33

21

-604

25.29,

1007.19,

-0.90

-0.02

-0.44

1.00

356

338

17312

-42

17

-13

-35

21

-605

25.29,

1007.19,

-0.88

-0.02

-0.47

1.00

346

336

17350

-42

17

-13

-37

22

-605

25.29,

1007.14,

— Reply to this email directly or view it on GitHub https://github.com/mjs513/FreeIMU-Updates/issues/25#issuecomment-87292146 . https://github.com/notifications/beacon/AFHhxbdOUDa5VgU5swLa3Pcsk-QhslUyks5n5v7agaJpZM4D2ZCz.gif

[cleaf30]

No I'm in Vermont and I adjusted my declination angle.

[mjs513]

OK just trying to see if the vector from x and z made sense. After I sent you the I also rotated the imu to see what values I would get and the vectors appeared correct for the rotation. On Mar 28, 2015 6:26 PM, "cleaf30" notifications@github.com wrote:

No I'm in Vermont and I adjusted my declination angle.

— Reply to this email directly or view it on GitHub https://github.com/mjs513/FreeIMU-Updates/issues/25#issuecomment-87323657 .

[cleaf30]

So you didn't turn it from (0.05, 0.01, 1.00) to (0.76, 0.00, 0.65)? - meaning you are experiencing the same issue but once it gets to the new vector(0.76, 0.00, 0.65) it reacts appropriately?

Also with DCM I've been experiencing G, the magnitude of the gravity vector, fluctuate from 1 to 2.

[mjs513]

Exactly. What is occurring is that the algorithm is converging from the starting values to the ones that are stabilized in the first few seconds as it expected the final vector is 0.76,0.00,0.65 . After that once you start moving it reacts appropriately.

Was just curious about DCM to see what you would get. Remember the angles are calculated based on the Direction Cosine Matrix and I am converting it to quaternions so the GUI will act appropriately. Convergence on DCM would be different. Also the did not tune the gains to for the FreeIMU. You would have to look up how to get the gravity vector direct from DCM to be accurate.

Mike

From: cleaf30 [mailto:notifications@github.com] Sent: Sunday, March 29, 2015 11:11 AM To: mjs513/FreeIMU-Updates Cc: Mike S Subject: Re: [FreeIMU-Updates] Unstable gravity vector (#25)

So you didn't turn it from (0.05, 0.01, 1.00) to (0.76, 0.00, 0.65)? - meaning you are experiencing the same issue but once it gets to the new vector(0.76, 0.00, 0.65) it reacts appropriately?

Also with DCM I've been experiencing G, the magnitude of the gravity vector, fluctuate from 1 to 2.

— Reply to this email directly or view it on GitHub https://github.com/mjs513/FreeIMU-Updates/issues/25#issuecomment-87426513 . https://github.com/notifications/beacon/AFHhxcjwXjTPGFPVa6A2BL07m308CaqVks5n6A1-gaJpZM4D2ZCz.gif

[cleaf30]

Mine isn't stabilizing. I've tried putting resets in my code and the RESET_Q() function has no effect however RESET() will give me good data for a few lines. The only difference in those functions is resetting MPU6050. I had to change the address to my MPU6050 because I have a real time clock in my project that had the same address so I soldered ADO to VCC and commented/uncommented for the new address in FreeIMU.h and it seemed fine. I also changed the default address in the MPU60X0 library just in case. Could it be referring to the old address somewhere else possibly taking data from the RTC?

[mjs513]

Don’t think so. I am assuming you tested with RTC out of the loop and everything worked. If not try it without the RTC. Also make sure you stick with Marg = 0, 1 or 3. Haven’t really played with DCM enough to be of any help.

Look at the mag values with and without the RTC or disable the magnetometer as an experiment. What RTC are you using?

From: cleaf30 [mailto:notifications@github.com] Sent: Sunday, March 29, 2015 12:38 PM To: mjs513/FreeIMU-Updates Cc: Mike S Subject: Re: [FreeIMU-Updates] Unstable gravity vector (#25)

Mine isn't stabilizing. I've tried putting resets in my code and the RESET_Q() function has no effect however RESET() will give me good data for a few lines. The only difference in those functions is resetting MPU6050. I had to change the address to my MPU6050 because I have a real time clock in my project that had the same address so I soldered ADO to VCC and commented/uncommented for the new address in FreeIMU.h and it seemed fine. I also changed the default address in the MPU60X0 library just in case. Could it be referring to the old address somewhere else possibly taking data from the RTC?

— Reply to this email directly or view it on GitHub https://github.com/mjs513/FreeIMU-Updates/issues/25#issuecomment-87438235 . https://github.com/notifications/beacon/AFHhxaWZVp1k2zilcA8dPZ1aT6UfV77Iks5n6CHggaJpZM4D2ZCz.gif

[cleaf30]

I tried it without the RTC and with magnetometer disabled neither had an effect. I'm using a DS1307 it's part of an adafruit data logging shield. I am also still getting the magnitude of the gravity vector to be around two with marg = 3. I though the getQ method would give me unit quaternion and after converting it to cartesian coordinates it would still be a unit vector. I'm currently seeing (1.73, -0.95, 0.04) which has a magnitude of 1.97

[mjs513]

Not sure what the issue is. Your original post showed that it was fairly stable after a few seconds which agreed with my tests. Take a look at your accel, gyro and mag values compared to what you originally posted. The only time you would see something like that occurring is if you moved the IMU quickly and then stopped moving. You will see a some overshoot but it should settle down again to stable values.

[cleaf30]

So would you suggest just doing a some math to scale the gravity vector to a unit vector. Here is some more data with marg = 3. where it is stable with a magnitude of 1 then I move it a bit and the magnitude drops to .17.

gx	gy	gz	G	raw[0]	raw[1]	raw[2]	raw[3]	raw[4]	raw[5]	raw[6]	raw[7]	raw[8]	temp	press
0.27	-0.04	-0.96	1.00	816	646	17282	-46	18	-13	-138	-132	-522	28.45	1009.60
0.27	-0.04	-0.96	1.00	848	670	17238	-46	19	-12	-141	-132	-523	28.45	1009.59
0.28	-0.04	-0.96	1.00	842	660	17232	-46	18	-13	-140	-130	-520	28.45	1009.59
0.28	-0.04	-0.96	1.00	798	682	17274	-45	18	-13	-140	-134	-521	28.45	1009.57
0.27	-0.04	-0.96	1.00	790	678	17250	-46	18	-13	-140	-129	-522	28.44	1009.56
0.29	-0.04	-0.96	1.00	854	666	17290	-45	18	-13	-138	-130	-525	28.44	1009.61
0.28	-0.04	-0.96	1.00	878	672	17202	-45	17	-12	-139	-131	-523	28.45	1009.63
0.28	-0.04	-0.96	1.00	852	670	17286	-46	18	-12	-138	-129	-525	28.45	1009.66
0.26	-0.04	-0.97	1.00	828	664	17300	-45	19	-12	-137	-129	-521	28.45	1009.66
0.28	-0.04	-0.96	1.00	812	676	17188	-46	18	-12	-139	-130	-521	28.45	1009.63
0.26	-0.04	-0.96	1.00	844	694	17162	-46	19	-12	-139	-131	-525	28.45	1009.61
0.29	-0.05	-0.96	1.00	806	672	17252	-46	19	-13	-137	-131	-521	28.45	1009.61
0.29	-0.04	-0.96	1.00	834	674	17286	-46	19	-13	-138	-131	-522	28.45	1009.62
0.30	-0.04	-0.95	1.00	816	672	17252	-45	18	-13	-137	-129	-523	28.45	1009.58
0.29	-0.04	-0.96	1.00	886	688	17266	-46	18	-13	-139	-129	-519	28.45	1009.58
0.26	-0.04	-0.96	1.00	824	658	17216	-46	20	-12	-141	-131	-524	28.45	1009.63
0.29	-0.04	-0.96	1.00	850	662	17236	-46	18	-12	-140	-130	-524	28.45	1009.65
0.28	-0.04	-0.96	1.00	830	688	17264	-45	18	-12	-141	-129	-526	28.45	1009.62
0.26	-0.05	-0.96	1.00	842	660	17230	-46	18	-13	-140	-132	-524	28.45	1009.61
0.26	-0.04	-0.97	1.00	846	678	17244	-45	19	-13	-137	-129	-520	28.45	1009.55
0.30	-0.04	-0.95	1.00	826	652	17250	-46	18	-12	-138	-129	-522	28.45	1009.56
0.27	-0.05	-0.96	1.00	842	704	17240	-46	18	-13	-140	-129	-522	28.45	1009.61
0.27	-0.04	-0.96	1.00	866	664	17264	-46	18	-13	-137	-131	-522	28.45	1009.61
0.28	-0.04	-0.96	1.00	850	712	17252	-46	18	-12	-140	-129	-521	28.45	1009.62
0.28	-0.04	-0.96	1.00	842	686	17304	-45	19	-13	-139	-130	-526	28.46	1009.62
0.26	-0.04	-0.96	1.00	850	694	17226	-45	18	-12	-138	-129	-524	28.46	1009.64
0.28	-0.04	-0.96	1.00	880	678	17268	-46	18	-12	-139	-131	-516	28.45	1009.63
0.27	-0.04	-0.96	1.00	812	690	17230	-45	18	-12	-137	-132	-521	28.45	1009.61
0.29	-0.04	-0.96	1.00	804	660	17230	-46	19	-12	-137	-130	-522	28.45	1009.62
0.27	-0.04	-0.96	1.00	848	676	17270	-45	18	-13	-139	-133	-521	28.45	1009.57
0.29	-0.04	-0.96	1.00	820	696	17254	-45	19	-12	-139	-129	-525	28.46	1009.58
0.28	-0.04	-0.96	1.00	842	684	17230	-46	18	-12	-137	-131	-523	28.46	1009.66
0.26	-0.04	-0.96	1.00	832	686	17234	-45	19	-13	-142	-134	-521	28.46	1009.65
0.26	-0.04	-0.97	1.00	846	676	17236	-46	19	-13	-141	-130	-524	28.46	1009.61
0.27	-0.04	-0.96	1.00	884	658	17260	-45	19	-13	-139	-128	-523	28.45	1009.60
0.30	-0.04	-0.95	1.00	868	702	17278	-46	18	-12	-137	-131	-523	28.45	1009.59
0.28	-0.04	-0.96	1.00	838	686	17278	-45	19	-12	-138	-133	-523	28.46	1009.60
0.27	-0.04	-0.96	1.00	796	698	17284	-45	19	-12	-141	-129	-521	28.46	1009.59
0.28	-0.04	-0.96	1.00	848	686	17232	-46	19	-12	-139	-132	-518	28.45	1009.58
0.28	-0.04	-0.96	1.00	874	654	17246	-46	18	-12	-139	-133	-521	28.45	1009.59
0.28	-0.04	-0.96	1.00	840	686	17196	-45	19	-12	-137	-130	-524	28.45	1009.60
0.28	-0.04	-0.96	1.00	842	682	17270	-46	19	-12	-142	-133	-523	28.45	1009.56
0.30	-0.04	-0.95	1.00	826	670	17292	-46	19	-12	-136	-131	-527	28.45	1009.56
0.28	-0.04	-0.96	1.00	900	692	17262	-45	18	-12	-142	-132	-518	28.45	1009.58
0.29	-0.04	-0.96	1.00	884	686	17230	-46	19	-13	-135	-131	-523	28.46	1009.59
0.28	-0.04	-0.96	1.00	850	654	17216	-45	19	-13	-141	-129	-524	28.46	1009.57
0.28	-0.04	-0.96	1.00	844	668	17250	-45	18	-13	-140	-133	-521	28.46	1009.57
0.29	-0.04	-0.96	1.00	808	654	17230	-45	18	-12	-139	-133	-520	28.46	1009.58
0.28	-0.04	-0.96	1.00	860	662	17288	-46	18	-13	-139	-131	-523	28.46	1009.57
0.29	-0.04	-0.96	1.00	844	686	17232	-46	18	-12	-139	-132	-522	28.46	1009.63
0.42	-0.01	-0.91	1.00	-1756	1234	15202	98	472	-35	-131	-133	-524	28.46	1009.63
0.20	-0.05	-0.98	1.00	188	892	16518	-99	-147	5	-140	-131	-523	28.46	1009.61
0.04	-0.07	0.10	0.13	774	708	17152	-47	19	-42	-141	-130	-522	28.46	1009.62
0.26	0.05	1.09	1.13	1026	574	17402	-29	87	-121	-140	-133	-522	28.46	1009.61
0.26	0.05	1.09	1.13	1024	620	17376	-44	22	-16	-139	-131	-521	28.46	1009.61
0.26	0.05	1.10	1.13	932	632	17238	-46	16	-12	-142	-131	-525	28.46	1009.61
0.26	0.05	1.10	1.13	822	710	17230	-46	19	-12	-135	-132	-522	28.46	1009.61
0.26	0.05	1.10	1.13	870	710	17208	-46	19	-13	-139	-130	-522	28.46	1009.58
0.26	0.05	1.10	1.13	812	682	17258	-45	18	-12	-136	-134	-521	28.46	1009.59
0.26	0.05	1.10	1.13	772	666	17250	-46	19	-13	-141	-135	-519	28.46	1009.63
0.26	0.05	1.10	1.13	844	678	17218	-46	18	-13	-139	-133	-518	28.46	1009.63
0.26	0.05	1.10	1.13	826	636	17286	-46	19	-13	-139	-132	-517	28.46	1009.59
0.25	0.05	1.10	1.13	876	692	17212	-45	18	-12	-139	-131	-519	28.47	1009.60
0.25	0.05	1.10	1.13	862	692	17264	-45	19	-12	-142	-133	-525	28.47	1009.61
0.29	-0.05	-0.96	1.00	830	688	17226	-46	18	-13	-138	-133	-524	28.47	1009.62
0.27	-0.04	-0.96	1.00	804	660	17254	-46	19	-13	-139	-133	-522	28.47	1009.62
0.28	-0.04	-0.96	1.00	838	698	17246	-46	19	-13	-140	-133	-523	28.46	1009.59
0.28	-0.04	-0.96	1.00	858	702	17216	-45	18	-12	-140	-132	-523	28.46	1009.61
0.27	-0.04	-0.96	1.00	888	682	17394	-45	19	-14	-140	-134	-519	28.46	1009.61
0.31	-0.04	-0.95	1.00	914	610	17330	-45	18	-13	-134	-132	-522	28.46	1009.55
0.30	-0.03	-0.95	1.00	302	490	17336	-47	15	-31	-135	-131	-526	28.46	1009.55
0.16	-0.09	-0.98	1.00	596	1434	17494	-50	7	-445	-138	-133	-522	28.46	1009.57
0.25	0.06	1.10	1.13	486	684	17016	-51	2	231	-140	-131	-521	28.46	1009.57
0.27	0.05	1.10	1.13	1406	1482	18404	-204	-362	68	-152	-127	-520	28.46	1009.62
0.32	0.04	1.09	1.13	998	924	18170	-270	-1015	-3	-179	-120	-508	28.47	1009.63
0.40	0.02	1.07	1.14	5416	-898	21632	-599	-1956	-356	-226	-115	-489	28.47	1009.62
0.50	0.02	1.04	1.15	3740	-174	19978	-302	-2217	-418	-295	-111	-454	28.46	1009.61
0.60	0.03	1.01	1.17	4888	-498	18330	-57	-2409	-314	-344	-118	-423	28.46	1009.60
0.70	0.05	0.97	1.19	8166	100	17690	-85	-2233	-470	-389	-119	-388	28.47	1009.62
0.80	0.06	0.93	1.22	7808	-2	16262	-171	-2444	-321	-437	-124	-348	28.47	1009.60
0.90	0.08	0.87	1.25	11782	818	13576	-245	-2601	-612	-467	-129	-307	28.47	1009.58
0.95	0.08	0.85	1.27	10014	514	11482	-860	-499	147	-483	-115	-294	28.47	1009.56
0.93	0.03	0.86	1.26	8470	-1122	11932	-1389	2531	817	-455	-83	-339	28.47	1009.57
0.73	-0.10	0.94	1.20	8516	-2156	13640	-2983	6585	1556	-337	-10	-444	28.47	1009.60
0.43	-0.26	1.01	1.13	5664	-2430	13832	-2894	6851	1339	-169	70	-517	28.46	1009.59
0.18	-0.35	1.03	1.11	2400	-4288	13770	-730	4409	603	-78	95	-547	28.46	1009.59
0.02	-0.37	1.04	1.10	-1882	-4780	14572	-413	3646	463	62	103	-565	28.47	1009.60
-0.14	-0.39	1.03	1.11	-3260	-4744	12884	-473	2650	976	167	115	-562	28.47	1009.62
-0.23	-0.39	1.03	1.12	-4274	-5276	11506	21	1453	676	208	108	-555	28.47	1009.61
-0.30	-0.39	1.02	1.14	-5554	-5280	11052	-287	1059	820	242	104	-550	28.47	1009.56
-0.33	-0.40	1.03	1.15	-7264	-4686	11044	-94	-383	726	231	101	-558	28.47	1009.57
-0.28	-0.37	1.05	1.15	-6506	-4302	13438	723	-2847	420	159	77	-566	28.47	1009.57
-0.12	-0.32	1.09	1.14	-6900	-5186	17924	1206	-4028	195	49	46	-567	28.47	1009.57
0.05	-0.26	1.11	1.14	-4950	-4546	18792	1115	-3488	-29	-45	18	-560	28.47	1009.57
0.17	-0.20	1.11	1.14	-1962	-3790	18348	1078	-1989	193	-102	-6	-546	28.46	1009.56
0.23	-0.15	1.12	1.15	-612	-3070	19056	851	-867	5	-124	-24	-537	28.46	1009.60
0.24	-0.13	1.12	1.15	-202	-2470	18462	235	258	109	-125	-33	-538	28.47	1009.61
0.22	-0.12	1.13	1.15	718	-2344	18014	91	493	142	-108	-33	-541	28.47	1009.62
0.21	-0.11	1.13	1.15	986	-1714	18734	306	-232	-74	-119	-46	-532	28.47	1009.62
0.24	-0.10	1.13	1.16	886	-1658	17976	298	-565	180	-134	-56	-532	28.47	1009.63
0.26	-0.08	1.13	1.16	548	-1424	17594	348	-565	123	-147	-58	-525	28.47	1009.63
0.28	-0.06	1.13	1.17	358	-936	17350	490	-182	47	-155	-74	-527	28.47	1009.61
0.28	-0.04	1.13	1.17	760	-352	17086	641	-108	49	-154	-88	-523	28.46	1009.60
0.28	0.00	1.14	1.17	1080	-62	17752	1036	61	-14	-150	-112	-521	28.46	1009.61
0.26	0.04	1.14	1.17	1142	1224	17242	41	141	-112	-146	-116	-523	28.47	1009.63
0.26	0.04	1.14	1.17	784	1026	17366	-42	55	-172	-144	-116	-521	28.47	1009.56
0.26	0.04	1.14	1.17	1014	988	17786	-40	35	-40	-142	-119	-524	28.47	1009.56
0.26	0.04	1.14	1.17	536	928	17006	-55	-24	-95	-146	-118	-523	28.47	1009.62
0.26	0.04	1.13	1.17	810	1398	17286	-53	-11	-87	-144	-119	-520	28.47	1009.61
0.26	0.04	1.13	1.16	944	664	17318	-34	70	-18	-146	-115	-521	28.47	1009.61
0.26	0.04	1.14	1.17	804	660	17262	-43	33	-13	-142	-119	-521	28.47	1009.62
0.26	0.04	1.14	1.17	826	652	17268	-45	21	-13	-143	-120	-521	28.47	1009.60
0.26	0.04	1.14	1.17	794	672	17286	-46	20	-13	-142	-119	-523	28.48	1009.61
0.26	0.04	1.14	1.17	822	664	17266	-45	19	-12	-146	-119	-522	28.48	1009.61
0.17	-0.04	-0.98	1.00	812	648	17222	-45	18	-13	-142	-118	-524	28.47	1009.59
0.05	-0.08	0.14	0.17	820	630	17240	-45	18	-13	-146	-117	-523	28.47	1009.59
0.05	-0.08	0.14	0.17	792	620	17244	-46	19	-12	-145	-119	-524	28.47	1009.61
0.05	-0.08	0.14	0.17	816	686	17232	-46	18	-12	-144	-118	-522	28.47	1009.60
0.05	-0.08	0.14	0.17	818	650	17262	-46	18	-12	-143	-118	-524	28.48	1009.61
0.05	-0.08	0.14	0.17	834	678	17246	-46	19	-12	-147	-117	-523	28.48	1009.64
0.05	-0.08	0.14	0.17	824	624	17272	-46	19	-13	-143	-119	-526	28.48	1009.65
0.05	-0.08	0.14	0.17	796	604	17314	-45	18	-11	-143	-122	-517	28.48	1009.62
0.05	-0.08	0.14	0.17	828	672	17264	-46	19	-12	-144	-119	-521	28.48	1009.60
0.05	-0.08	0.14	0.17	828	632	17266	-46	19	-13	-144	-119	-525	28.48	1009.64
0.05	-0.08	0.14	0.17	846	658	17232	-46	18	-12	-145	-123	-524	28.48	1009.65
0.05	-0.08	0.14	0.17	834	660	17282	-46	19	-12	-144	-119	-522	28.48	1009.65
0.05	-0.08	0.14	0.17	804	684	17214	-45	19	-13	-147	-117	-523	28.48	1009.65
0.05	-0.08	0.14	0.17	804	650	17236	-45	18	-13	-143	-119	-521	28.48	1009.58
0.05	-0.08	0.14	0.17	824	640	17258	-46	18	-12	-143	-118	-519	28.48	1009.57
0.05	-0.08	0.14	0.17	792	652	17214	-46	19	-13	-140	-116	-521	28.48	1009.62
0.05	-0.08	0.14	0.17	836	664	17290	-46	19	-12	-142	-118	-523	28.48	1009.63
0.05	-0.08	0.14	0.17	826	682	17208	-45	18	-12	-145	-118	-521	28.48	1009.60
0.05	-0.08	0.14	0.17	848	664	17238	-45	19	-12	-147	-116	-523	28.48	1009.59
0.05	-0.08	0.15	0.17	840	668	17254	-46	18	-13	-145	-122	-523	28.48	1009.59
0.05	-0.08	0.15	0.17	820	644	17228	-47	18	-13	-144	-119	-523	28.49	1009.62
0.05	-0.08	0.15	0.17	802	672	17290	-46	17	-13	-145	-117	-524	28.49	1009.60
0.05	-0.08	0.15	0.17	812	640	17228	-45	18	-12	-142	-120	-524	28.49	1009.59
0.05	-0.08	0.15	0.17	850	672	17284	-45	19	-12	-143	-118	-522	28.49	1009.63
0.05	-0.08	0.15	0.17	824	662	17284	-46	19	-13	-144	-119	-522	28.48	1009.62
0.05	-0.08	0.15	0.18	844	648	17206	-45	17	-12	-143	-119	-521	28.48	1009.60
0.05	-0.08	0.15	0.18	814	652	17242	-46	19	-12	-145	-119	-518	28.49	1009.61
0.05	-0.08	0.15	0.18	790	658	17298	-47	18	-12	-142	-119	-522	28.49	1009.59
0.05	-0.08	0.15	0.18	850	668	17262	-46	18	-12	-142	-119	-527	28.50	1009.61
0.05	-0.08	0.15	0.18	856	666	17202	-46	18	-13	-141	-118	-523	28.50	1009.65
0.05	-0.08	0.15	0.18	792	640	17294	-46	18	-13	-143	-121	-521	28.49	1009.63
0.05	-0.08	0.15	0.18	832	662	17226	-46	18	-13	-146	-120	-519	28.49	1009.58
0.05	-0.08	0.15	0.18	854	656	17206	-45	18	-12	-144	-121	-524	28.49	1009.57
0.05	-0.08	0.15	0.18	852	668	17256	-46	18	-12	-147	-120	-519	28.49	1009.59
0.05	-0.08	0.15	0.18	810	636	17274	-46	18	-12	-149	-121	-519	28.50	1009.61
0.05	-0.08	0.15	0.18	818	640	17218	-45	18	-12	-141	-118	-523	28.50	1009.63
0.05	-0.08	0.15	0.18	828	668	17262	-46	19	-13	-143	-119	-522	28.50	1009.63
0.05	-0.08	0.15	0.18	798	680	17288	-46	18	-12	-142	-119	-523	28.50	1009.62
0.05	-0.08	0.15	0.18	782	654	17228	-46	18	-13	-141	-115	-525	28.49	1009.60
0.05	-0.08	0.15	0.18	846	646	17270	-45	18	-12	-141	-119	-522	28.49	1009.63
0.05	-0.08	0.15	0.18	844	632	17252	-46	18	-13	-142	-118	-523	28.50	1009.64
0.05	-0.08	0.16	0.18	810	628	17216	-45	18	-12	-146	-121	-523	28.50	1009.60
0.05	-0.08	0.16	0.18	798	656	17264	-46	18	-13	-145	-118	-524	28.49	1009.58
0.05	-0.08	0.16	0.18	804	638	17248	-45	18	-13	-141	-117	-522	28.49	1009.60
0.05	-0.08	0.16	0.18	854	680	17276	-45	18	-13	-141	-119	-524	28.50	1009.62
0.05	-0.08	0.16	0.18	824	670	17256	-45	18	-13	-142	-118	-522	28.50	1009.63
0.05	-0.08	0.16	0.18	832	656	17282	-46	19	-12	-143	-118	-522	28.50	1009.64
0.05	-0.08	0.16	0.18	780	658	17246	-46	18	-13	-142	-119	-520	28.50	1009.59
0.05	-0.08	0.16	0.18	862	642	17208	-46	19	-12	-142	-122	-522	28.50	1009.59
0.05	-0.08	0.16	0.19	828	646	17258	-45	19	-12	-147	-117	-520	28.50	1009.63
0.05	-0.08	0.16	0.19	816	656	17242	-46	18	-12	-145	-119	-522	28.49	1009.61
0.05	-0.08	0.16	0.19	830	622	17228	-45	18	-13	-142	-118	-522	28.49	1009.61
0.05	-0.08	0.16	0.19	852	672	17228	-46	18	-12	-144	-118	-518	28.50	1009.63
0.05	-0.08	0.16	0.19	844	672	17208	-46	18	-12	-144	-121	-523	28.50	1009.57
0.05	-0.08	0.16	0.19	814	662	17236	-45	18	-13	-144	-116	-522	28.50	1009.58
0.05	-0.08	0.16	0.19	804	664	17274	-45	18	-13	-142	-118	-521	28.50	1009.62
0.05	-0.08	0.16	0.19	832	642	17234	-45	19	-12	-144	-118	-522	28.50	1009.63
0.05	-0.08	0.16	0.19	826	654	17232	-45	18	-13	-145	-117	-524	28.50	1009.62
0.05	-0.08	0.16	0.19	848	662	17232	-46	19	-12	-143	-117	-523	28.50	1009.59
0.05	-0.08	0.16	0.19	794	664	17286	-46	18	-12	-144	-118	-525	28.50	1009.62
0.05	-0.08	0.16	0.19	832	666	17250	-45	18	-13	-142	-120	-522	28.50	1009.63
0.05	-0.08	0.16	0.19	834	694	17274	-46	18	-12	-144	-122	-524	28.50	1009.59
0.05	-0.08	0.16	0.19	830	650	17240	-45	19	-12	-147	-118	-524	28.50	1009.59

It has been sitting for a while now and it stabilizes to a magnitude of 1 but the g vector is (0.54,-0.05,-0.84). I give it a 90 degree turn and to settles at (0.99,0.04,17). If I keep it the xy plane horizontal shouldn't the g vector be about (0,0,1)?

[mjs513]

A couple of things. I am kind of curious that your accel and mag values are a bit different when at rest compared to your original post. One of things you will read is that the there are variations in calibration values depending on temperature. Also, I had to do the calibration a couple of times after first use. So you might what to do another calibration.

As for your question on gravity vector, not necessarily. Depends where you are on the earth, Try printing ypr at the same time - you might see you are not perfectly level. Try leveling it out and see what you get for the gravity vector.

[cleaf30]

You're right about the calibration. I've calibrated multiple times and have gotten consistent results however when I go back to the calibration.h file that comes with the FreeIMU library my IMU works much better. The main discrepancy is the z axis acceleration offset. ~700 in my calibration.h compared to ~1600 in the file that comes with the library. I've changed the z axis acc offset in my file and that works as well.

[mjs513]

Hi Cody

Based on your data your z-axis scale should be around 17300 based on your raw data. Check the GUI and see if you have word = 2. Word =2 is for 16 bit processors like the mega. Something funny is going with the cal file. That is why you are probably getting strange values.

Mike

From: cleaf30 [mailto:notifications@github.com] Sent: Wednesday, April 01, 2015 5:09 PM To: mjs513/FreeIMU-Updates Cc: Mike S Subject: Re: [FreeIMU-Updates] Unstable gravity vector (#25)

You're right about the calibration. I've calibrated multiple times and have gotten consistent results however when I go back to the calibration.h file that comes with the FreeIMU library my IMU works much better. The main discrepancy is the z axis acceleration offset. ~700 in my calibration.h compared to ~1600 in the file that comes with the library. I've changed the z axis acc offset in my file and that works as well.

— Reply to this email directly or view it on GitHub https://github.com/mjs513/FreeIMU-Updates/issues/25#issuecomment-88632323 . https://github.com/notifications/beacon/AFHhxYrrPOmBDQ5tR03cH8L6nX3L-DkTks5n7FXjgaJpZM4D2ZCz.gif