ou2356
commented
2 years ago 顺便提一句，由于我想把ICM20948应用在无人机上面，于是就把DMP的加速度、陀螺仪数据输出速率设置成了1125Hz（由于我想用校准后的陀螺仪的值，所以选择用DMP来获得数据），但是实际只有700Hz的输出速率，而且当我的SPI通信速率为4210526Hz会有一个突然地出现一个很高或者很低的数值，这种现象无论是加速度计、陀螺仪和磁力计都会有。但是SPI刚好为4MHz时是不会有这个现象的，甚至SPI为3809523Hz时也会出现这种数据异常的现象，下图为一个陀螺仪的Z轴在静止状态下的数据图:
Google Translate: By the way, since I want to apply the ICM20948 to the drone, I set the DMP acceleration and gyroscope data output rate to 1125Hz (because I want to use the calibrated gyroscope value, so I choose to use DMP to Get data), but the actual output rate is only 700Hz, and when my SPI communication rate is 4210526Hz, there will be a sudden high or low value, this phenomenon will be accelerometer, gyroscope and magnetometer. Have. However, this phenomenon will not occur when the SPI is just 4MHz, and even when the SPI is 3809523Hz, this data abnormality phenomenon will occur. The following picture shows the data of the Z axis of a gyroscope in a static state:
数据图为MATLAB从串口中获得数据然后作出的图，下面附上MATLAB代码：
#
clear;
dispTime = 2; %单位(s) fps = 60; samp_freq = 1125; %单位(Hz) lenght = samp_freq*dispTime;
y1 = zeros(1,lenght); y2 = zeros(1,lenght); device = serialport("COM6", 2000000, "DataBits", 8, "Parity", "none", "StopBits", 1); x1 = 1/samp_freq:1/samp_freq:dispTime; % write(device,sin(0:2pi/lenght:2pi),"double"); i=1; fps = samp_freq/fps;
% 两组数据分开两个图画
% while true
% temp = read(device,2,"double");
% if size(temp) == 0
% break;
% end
%
% if i>lenght
% y1 = [y1(2:end) temp(1,1)];
% y2 = [y2(2:end) temp(1,2)];
% else
% y1(1,i) = temp(1,1);
% y2(1,i) = temp(1,2);
% end
%
% if rem(i,fps) == 0
% subplot(2,1,1);
% plot(x1,y1,'b-');
% subplot(2,1,2);
% plot(x1,y2,'r:');
% end
% i = i+1;
% end
% 两组数据画在一个图
% while true
% temp = read(device,2,"double");
% if size(temp) == 0
% break;
% end
%
% if i>lenght
% y1 = [y1(2:end) temp(1,1)];
% y2 = [y2(2:end) temp(1,2)];
% else
% y1(1,i) = temp(1,1);
% y2(1,i) = temp(1,2);
% end
%
% if rem(i,fps) == 0
% plot(x1,y1,'b-',x1,y2,'r:');
% end
% i = i+1;
% end
% 一组数据画在一个图 while true temp = read(device,1,"double"); if size(temp) == 0 break; end if i>lenght y1 = [y1(2:end) temp(1,1)]; else y1(1,i) = temp(1,1); end if rem(i,fps) == 0 plot(x1,y1,'b-'); end i = i+1; end clear; #
PaulZC
Subject of the issue
@PaulZC你好，首先非常感谢你贡献的代码，这边我想对前人提出的陀螺仪校准问题进行讨论。
Google Translate: Hello @PaulZC , first of all thank you very much for the code you contributed, here I want to discuss the problem of gyroscope calibration raised by the predecessors.
Your workbench
我在brawner的代码中看到了关于陀螺仪校准的内容，(https://github.com/isouriadakis/Arduino_ICM20948_DMP_Full-Function/blob/a13508d8145e003ea83190187047fb9dc247c6fc/ICM20948/Icm20948Setup.c#L625-L632) 他的代码中注释为满量程为2^20，且固定为2000dps，然后我对他进行了如下代码处理，效果还是不错的，可以实现一定的校准。也非常感谢@brawner的代码的辛勤付出。
Google Translate: I saw the content about gyroscope calibration in brawner 's code. His code is commented that the full scale is 2^20, and it is fixed at 2000dps, and then I processed him with the following code, the effect is still good, it can be achieved certain calibration. Also a big thanks to @brawner for the hard work on the code.
# int16_t x, y, z; int16_t gyrBias[3] = {0}; gyrBias[0] = data.Raw_Gyro.Data.BiasX >> (5 - dps2000 + icmSettings.gyr_fsr); gyrBias[1] = data.Raw_Gyro.Data.BiasY >> (5 - dps2000 + icmSettings.gyr_fsr); gyrBias[2] = data.Raw_Gyro.Data.BiasZ >> (5 - dps2000 + icmSettings.gyr_fsr); x = data.Raw_Gyro.Data.X - gyrBias[0]; //校准后的数据 y = data.Raw_Gyro.Data.Y - gyrBias[1]; //校准后的数据 z = data.Raw_Gyro.Data.Z - gyrBias[2]; //校准后的数据 # 我想说的是data.Raw_Gyro.Data.BiasX，data.Raw_Gyro.Data.BiasY，data.Raw_Gyro.Data.BiasZ并不是僵尸数据，他们是真实有用的。
Google Translate: What I want to say is that data.Raw_Gyro.Data.BiasX, data.Raw_Gyro.Data.BiasY, data.Raw_Gyro.Data.BiasZ are not zombie data, they are real and useful.
我的配置代码如下： // Enable any additional sensors / features success &= (myICM.enableDMPSensor(INV_ICM20948_SENSOR_GYROSCOPE) == ICM_20948_Stat_Ok);
success &= (myICM.setDMPODRrate(DMP_ODR_Reg_Gyro, 0) == ICM_20948_Stat_Ok); // Set to the maximum
加速度和陀螺仪的输出速率都设置成了225Hz。
由于我并没有使用Arduino IDE来使用您的库代码，我对你的例程代码加入了自己的一些代码实现，所以我这里就不把代码全部贴出来了，以免让你混淆，如果你需要的话请随时告诉我，我很乐意共享它。
Google Translate: The accelerometer and gyroscope output rates are both set to 225Hz.
Since I didn't use the Arduino IDE to use your library code, I added some of my own code implementation to your routine code, so I won't post all the code here, so as not to confuse you, if you need it Please feel free to let me know, I'd love to share it.