Test Bench APA95ML

1. Setup
- 1.1. Parameters
- 1.2. Filter White Noise
2. Run Experiment and Save Data
- 2.1. Load Data
- 2.2. Save Data
3. Huddle Test
- 3.1. Time Domain Data
- 3.2. PSD of Measurement Noise
4. Transfer Function Estimation with \(m=5kg\)
5. PI Amplifier

Figure 1: Picture of the Setup

Figure 2: Zoom on the APA

1 Setup

1.1 Parameters

Ts = 1e-4;

1.2 Filter White Noise

Glpf = 1/(1 + s/2/pi/500);

Gz = c2d(Glpf, Ts, 'tustin');

2 Run Experiment and Save Data

2.1 Load Data

data = SimulinkRealTime.utils.getFileScopeData('data/apa95ml.dat').data;

2.2 Save Data

u = data(:, 1); % Input Voltage [V]
y = data(:, 2); % Output Displacement [m]
t = data(:, 3); % Time [s]

save('./mat/huddle_test.mat', 't', 'u', 'y', 'Glpf');

3 Huddle Test

3.1 Time Domain Data

Figure 3: Measurement of the Mass displacement during Huddle Test

3.2 PSD of Measurement Noise

Ts = t(end)/(length(t)-1);
Fs = 1/Ts;

win = hanning(ceil(1*Fs));

[pxx, f] = pwelch(y, win, [], [], Fs);

Figure 4: Amplitude Spectral Density of the Displacement during Huddle Test

4 Transfer Function Estimation with \(m=5kg\)

4.1 Time Domain Data

Figure 5: Time domain signals during the test

4.2 Comparison of the PSD with Huddle Test

Ts = t(end)/(length(t)-1);
Fs = 1/Ts;

win = hanning(ceil(1*Fs));

[pxx, f] = pwelch(y, win, [], [], Fs);
[pht, ~] = pwelch(ht.y, win, [], [], Fs);

Figure 6: Comparison of the ASD for the identification test and the huddle test

4.3 Compute TF estimate and Coherence

Ts = t(end)/(length(t)-1);
Fs = 1/Ts;

win = hann(ceil(1/Ts));

[tf_est, f] = tfestimate(u, -y, win, [], [], 1/Ts);
[co_est, ~] = mscohere(  u, -y, win, [], [], 1/Ts);

Figure 7: Coherence

Figure 8: Estimation of the transfer function from input voltage to displacement

4.4 Comparison with the FEM model

load('mat/fem_model_5kg.mat', 'Ghm');

Figure 9: Comparison of the identified transfer function and the one estimated from the FE model

5 PI Amplifier

5.1 Comparison of the PSD with Huddle Test

Ts = t(end)/(length(t)-1);
Fs = 1/Ts;

win = hanning(ceil(1*Fs));

[pxx, f] = pwelch(y, win, [], [], Fs);
[pht, ~] = pwelch(ht.y, win, [], [], Fs);

Figure 10: Comparison of the ASD for the identification test and the huddle test

5.2 Compute TF estimate and Coherence

Ts = t(end)/(length(t)-1);
Fs = 1/Ts;

win = hann(ceil(10/Ts));

[tf_est, f] = tfestimate(u, -y, win, [], [], 1/Ts);
[co_est, ~] = mscohere(  u, -y, win, [], [], 1/Ts);

Figure 11: Coherence

Figure 12: Estimation of the transfer function from input voltage to displacement

5.3 Comparison with the FEM model

load('mat/fem_model_5kg.mat', 'Ghm');

Figure 13: Comparison of the identified transfer function and the one estimated from the FE model