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Lead-Lag / Washout
First-order compensator. Lead-Lag is K(1+sT1)/(1+sT2): phase lead when T1 > T2, lag when T1 < T2. Washout is K·sT/(1+sT): it passes changes and removes any steady offset. Filtered Derivative is K·s/(1+sT): a derivative with a first-order roll-off. Discretized with forward Euler; a zero time constant removes its term (T2 = 0 leaves a pure lead, T = 0 a pure derivative). The block starts in steady state for its first input, so it does not kick at t = 0.
Category: Continuous
Ports
| Port | Kind | Signal | Notes |
|---|---|---|---|
in | Control input | Real | |
out | Control output | Real |
Parameters
| Parameter | Type | Default | Units | Description | ID |
|---|---|---|---|---|---|
| Type | Choice: Lead-Lag / Washout / Filtered Derivative | Lead-Lag | — | Lead-Lag = K(1+sT1)/(1+sT2). Washout = K·sT/(1+sT). Filtered Derivative = K·s/(1+sT). | type |
| K | Number | 1 | — | Gain. For Filtered Derivative it multiplies the derivative, so it has units of seconds. | K |
| T1 | Number | 0.1 | s (also ms) | Lead (numerator) time constant. | T1 |
| T2 | Number | 0.02 | s (also ms) | Lag (denominator) time constant. | T2 |
| T | Number | 1 | s (also ms) | Time constant of the washout or of the derivative's roll-off. | T |