AnsweredAssumed Answered

Getting odd jumps in output values

Question asked by SCOTT MILLER on May 7, 2019
Latest reply on Jun 11, 2019 by SCOTT MILLER

I'm processing 9DOF data from a Bosch BMX055 at 40 Hz, and for the moment I'm focusing on yaw because that seems to be the most stable output value.  It's giving me some weird jumps, though.  Here's an example:

 

M:[278226] Roll 004 Pitch -02 Yaw 079
M:[278232] G -0095 -0057 00826  A -0012 -0010 00113  M 01129 -0575 00077
M:[278232] Roll 003 Pitch -02 Yaw 078
M:[278238] G -0124 -0148 01317  A 00014 -0010 00129  M 01129 -0575 00077
M:[278238] Roll 003 Pitch -02 Yaw 075
M:[278244] G -0101 -0180 01135  A -0034 -0020 00104  M 01065 -0591 00109
M:[278244] Roll 003 Pitch -02 Yaw 307
M:[278250] G -0058 -0028 00367  A -0009 -0010 00109  M 01065 -0591 00109
M:[278250] Roll 003 Pitch -02 Yaw 293
M:[278256] G -0077 -0036 00483  A -0017 -0010 00116  M 01049 -0599 00089
M:[278256] Roll 003 Pitch -02 Yaw 290
M:[278262] G -0057 00000 00343  A -0011 -0010 00113  M 01049 -0623 00101

The log lines alternate between raw sensor readings and the fusion results.  The raw readings show gyro X, Y, and Z, followed by accelerometer X, Y, Z and magnetometer X, Y, Z.  The board is being rotated by hand slowly around the Z axis.

 

At timestamp 278244 you can see that the yaw value jumps from 75 to 307 degrees.  I don't see any corresponding jumps in the input values.

 

Here are two more, with more samples shown:

 

M:[327400] G -0010 00033 00132  A -0005 -0007 00112  M 01177 -0439 00075
M:[327400] Roll 003 Pitch -04 Yaw 090
M:[327406] G -0002 -0010 00277  A -0010 -0008 00114  M 01137 -0447 00035
M:[327406] Roll 003 Pitch -04 Yaw 090
M:[327412] G -0006 -0004 00365  A -0011 -0009 00114  M 01153 -0367 00059
M:[327412] Roll 003 Pitch -04 Yaw 090
M:[327418] G -0011 00021 00276  A -0009 -0009 00114  M 01153 -0367 00059
M:[327418] Roll 003 Pitch -04 Yaw 090
M:[327424] G -0018 00035 00253  A -0005 -0007 00113  M 01129 -0415 00067
M:[327424] Roll 003 Pitch -04 Yaw 090
M:[327430] G -0011 00010 00469  A -0013 -0009 00113  M 01129 -0415 00067
M:[327430] Roll 003 Pitch -04 Yaw 089
M:[327436] G -0008 00014 00489  A -0010 -0008 00113  M 01169 -0415 00047
M:[327436] Roll 003 Pitch -04 Yaw 089
M:[327442] G -0008 00013 00488  A -0013 -0010 00115  M 01145 -0423 00073
M:[327442] Roll 003 Pitch -04 Yaw 089
M:[327448] G -0013 00023 00437  A -0009 -0007 00113  M 01145 -0423 00073
M:[327448] Roll 003 Pitch -04 Yaw 088
M:[327454] G 00000 00005 00468  A -0013 -0012 00116  M 01105 -0367 00063
M:[327454] Roll 003 Pitch -04 Yaw 088
M:[327460] G -0012 00022 00351  A -0010 -0009 00115  M 01105 -0367 00063
M:[327460] Roll 003 Pitch -03 Yaw 088
M:[327466] G -0004 00012 00341  A -0008 -0008 00112  M 01129 -0463 00035
M:[327466] Roll 003 Pitch -03 Yaw 088
M:[327472] G -0009 00007 00412  A -0009 -0008 00114  M 01073 -0455 00069
M:[327472] Roll 003 Pitch -03 Yaw 088
M:[327478] G -0001 00005 00439  A -0013 -0010 00114  M 01073 -0455 00069
M:[327478] Roll 003 Pitch -03 Yaw 088
M:[327484] G -0005 00009 00316  A -0006 -0005 00114  M 01105 -0471 00031
M:[327484] Roll 003 Pitch -03 Yaw 088
M:[327490] G -0007 00012 00296  A -0011 -0010 00112  M 01105 -0471 00031
M:[327490] Roll 003 Pitch -03 Yaw 089
M:[327496] G -0009 00015 00216  A -0007 -0009 00115  M 01105 -0471 00029
M:[327496] Roll 003 Pitch -03 Yaw 257
M:[327502] G 00005 -0024 00331  A -0013 -0011 00114  M 01081 -0479 00035
M:[327502] Roll 003 Pitch -03 Yaw 218



M:[042282] G -0009 00006 -0656  A -0005 -0006 00114  M 00921 00049 -0063
M:[042282] Roll -03 Pitch 005 Yaw 326
M:[042288] G 00004 00005 -0564  A -0006 -0008 00114  M 00921 00049 -0063
M:[042288] Roll -03 Pitch 006 Yaw 327
M:[042294] G 00001 -0008 -0570  A -0006 -0008 00113  M 00953 00113 -0043
M:[042294] Roll -03 Pitch 006 Yaw 328
M:[042300] G -0001 -0014 -0381  A -0007 -0008 00115  M 00969 00057 -0047
M:[042300] Roll -03 Pitch 006 Yaw 329
M:[042306] G 00002 -0020 -0016  A -0007 -0007 00113  M 00969 00057 -0047
M:[042306] Roll -03 Pitch 006 Yaw 329
M:[042312] G -0001 -0011 -0023  A -0004 -0008 00113  M 00961 00137 -0057
M:[042312] Roll -03 Pitch 006 Yaw 330
M:[042318] G -0018 00024 -0914  A -0007 -0010 00113  M 00961 00137 -0057
M:[042318] Roll -03 Pitch 006 Yaw 332
M:[042324] G -0021 00041 -1406  A -0006 -0008 00114  M 00929 00121 -0089
M:[042324] Roll -03 Pitch 006 Yaw 338
M:[042330] G -0008 00020 -1287  A -0006 -0005 00113  M 00945 00153 -0053
M:[042330] Roll -03 Pitch 006 Yaw 006
M:[042336] G -0003 -0031 -0418  A -0006 -0007 00114  M 00945 00153 -0053
M:[042336] Roll -03 Pitch 006 Yaw 041
M:[042342] G 00002 -0026 00006  A -0008 -0008 00113  M 00913 00129 -0069
M:[042342] Roll -03 Pitch 006 Yaw 038
M:[042348] G -0006 -0005 -0002  A -0007 -0008 00113  M 00913 00129 -0069
M:[042348] Roll -03 Pitch 006 Yaw 038
M:[042354] G 00001 -0004 -0008  A -0007 -0010 00114  M 00905 00201 -0055
M:[042354] Roll -03 Pitch 006 Yaw 038
M:[042360] G -0004 -0008 -0022  A -0007 -0009 00113  M 00929 00137 -0057
M:[042360] Roll -03 Pitch 006 Yaw 039
M:[042366] G -0009 -0012 -0088  A -0004 -0009 00114  M 00929 00137 -0057
M:[042366] Roll -03 Pitch 006 Yaw 039
M:[042372] G -0005 00011 -0484  A -0008 -0009 00113  M 00937 00209 -0059
M:[042372] Roll -03 Pitch 006 Yaw 039

 

Where should I start looking for the problem?  The raw values displayed here are being read straight out of the SFG FIFOs so that's what the system is working with.  My conversion factors are 33 counts per degree/sec, 128 counts per g, and 16 counts per uT.  In the last example, there's a peak gyro Z rate of -42.6 deg/sec, but the yaw jumps by 28 degrees in 1/40 sec.  What am I doing wrong?

 

Thanks,

 

Scott

Outcomes