How to conversion of Acceleration FFT to Velocity?

Dear friends

I have accerelation of vibration data from the device, I need to convert it into velocity. I've tried several times and still stuck, I can't import that data into the formula/function. I've attached an excel file I got from the device. maybe you can download and see the excel files for complete information. Could you guys help me, what function/formula should I write? Thank You

Answer 1

[Star Strider]

Perhaps something like this —

T1 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/994900/fantest.xlsx%20-%20Sheet2.xlsx', 'VariableNamingRule','preserve')

T1 = 717×6 table
    hours    Current    Voltage    axis x    axis y    axis z
    _____    _______    _______    ______    ______    ______

      1       0.182      228.8     -0.14     -0.25      0.84 
      2       0.181      228.8      -0.1     -0.22      0.84 
      3       0.182        229      0.07     -0.06      0.86 
      4       0.182      228.9      0.04     -0.12      0.86 
      5       0.181      228.7      0.02     -0.08      0.85 
      6       0.182      228.9      0.15     -0.01      0.86 
      7       0.182      229.1      0.02      -0.1      0.85 
      8       0.181      228.8      0.16      0.04      0.86 
      9       0.181      228.9      0.02     -0.12      0.84 
     10       0.181      228.6      0.25      0.14      0.89 
     11       0.181      228.7      0.19       0.1      0.87 
     12       0.181      228.9     -0.17     -0.23      0.84 
     13       0.181      228.8      0.17      0.09      0.88 
     14       0.182      229.1       0.3      0.17      0.89 
     15       0.182      229.2      0.29      0.12      0.87 
     16       0.182      229.5      0.12     -0.01      0.86 

VN = T1.Properties.VariableNames;

t = T1.hours;
x = T1.('axis x');
y = T1.('axis y');
z = T1.('axis z');

vel = cumtrapz(t,[x y z]);
velt = sqrt(sum(vel.^2,2));

figure
subplot(4,1,1)
plot(t, vel(:,1))
grid
title('x')
ylim([-1 1]*700)
subplot(4,1,2)
plot(t, vel(:,2))
grid
title('y')
ylim([-1 1]*700)
subplot(4,1,3)
plot(t, vel(:,3))
grid
title('z')
ylim([-1 1]*700)
subplot(4,1,4)
plot(t, velt)
grid
title('Net')
ylim([-1 1]*700)
sgtitle('Velocity')

Fs = 1;
V = lowpass(T1.Voltage, 0.015, Fs);
I = lowpass(T1.Current, 0.015, Fs);

figure
plot(t, V./I)
grid
xlabel('Time')
ylabel('Z')
title('Impedance')

EDIT — (11 May 2022 at 22:36)

The ‘z’ velocity appears to be integrating a constant, so correcting for that would likely be appropriate, since it is unlikely that a constant acceleration leading to a linearly-increasing velocity is what is actually being recorded here.

I doubt that taking the Fourier transform of the velocity would be very revealing, so I did not do it here.

.

[Phakapol Tungboontina]

Why script is error in line7 ?

vel = cumtrapz(t,[x y z]);

[Star Strider]

My code threw no errors.

I have no idea what the problem could be.

Answer 2

[Bora Eryilmaz]

The new convertVibration function in MATLAB R2024a release of the Predictive Maintenance Toolbox lets you compute baseline-corrected and filtered acceleration, velocity, and displacement signals from vibration measurements using a single sensor output from either an accelerometer, velocity sensor, or displacement sensor.