COMPUTE THE INTERSECTION OF THE CURVE WITH THE Y=0 AXIS AND RETURN THE X-VALUE AS SPECIFIED BELOW. USEFUL FOR DETERMINING THE TIME-TO-ZERO VELOCITY.¶
Finds the x-axis value (typically time) at which a curve crosses zero on the Y-axis, commonly used to extract the time-to-zero velocity from a velocity time-history. When multiple zero-crossings exist, the lookup type controls which intersection is returned (first, last, average, min, or max x-value).
When to use¶
Classification: process.
Tagged: curve-lookup, intersection, kinematics, time-to-zero, ttz, velocity, zero-crossing.
Inputs¶
| Label | ID | Type | Default | Required | Description |
|---|---|---|---|---|---|
| Curve 1 | curve1 | vector | — | Velocity time-history curve (X = time, Y = velocity) whose Y=0 crossing(s) will be located; accepts any curve vector but is most meaningful for velocity or similarly signed signals. | |
| Lookuptype | lookuptype | string | first | Selection strategy when multiple Y=0 crossings exist: ‘first’ (default) returns the earliest, ‘last’ the latest, ‘average’ the mean x-value across all crossings, ‘min’ the smallest x-value, and ‘max’ the largest x-value. |
Outputs¶
| Label | ID | Type | Description |
|---|---|---|---|
| curve_lookup_ttz_output_1 | curve_lookup_ttz_output_1 | scalar | Scalar x-axis value (e.g., time in ms) at which the input curve intersects Y=0, resolved according to the chosen lookup type. |
Disciplines¶
- data.curve.transform
- engineering.crash.dynamics
Runnable example¶
A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: /api/workflow/example?id=curve_lookup_ttz
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