Use Experiment 18E to study the relationship between acceleration feedback and system sample time.

Use the Live Scope display to see instability caused by excessive values of K_AFB.

a. Make a table that shows the relationship between the maximum allowable K_AFB with the system-observer sample time (T_SAMPLE) set at 0.00025, 0.0002, and 0.00015.

b. Compare the improvement in low-frequency disturbance response (say, 10 Hz) for each of the three settings with the baseline system (K_AFB = 0). (Set T Sample to 0.0001s for this part; this improves the readings from the DSA without requiring you to change the FFT sample time.)

c. Compare the results in part b with the ideal improvement gained by using acceleration feedback (see Equation 18.3).

CmdDsa [V Td ** 5E+09 0.002dtdt Jt DistDsa < > 42 850 Command Vo KVP KVI 00000000 CmdDsa Cmd Dsa Disturbance 1200 Bandwidth HOO! Digital Pl 00000 Distosa Dist Dsa Clamp Current Loop 1 Scale1: 5 (Off 10) Scale2 10 (0-10). Time. 0.002 To Ve < >> 1 0.002 KtEst JtEst 5E+06 KIO 3500 KDO Vm Digital PID(2) Sum Sum Delay < > 0.00025 TSomple 0 KAFB Ao 1 Solver Main