The STEP(a, x1, y1, x2, y2) function returns a smooth step function applied to an expression a for time or for a result.
The
smooth cubic function starts rising at (x1,y1) on the horizontal axis, and levels off at (x2,y2). Use this function in expressions for forces or
motors.
Format
STEP(a,
x1, y1, x2, y2)
Arguments
| a |
Select any valid result from the
list, or enter time. |
| x1 |
The point on the horizontal axis
at which the step begins to rise. |
| y1 |
The value of the step function
before the point x1. |
| x2 |
The point on the horizontal axis
at which the step levels off. |
| y2 |
The value of the step function at
the leveling off point x2. |
Step Function Equation
The STEP function approximates the Heaviside step function with a cubic polynomial.
| Function |
Definition
|
STEP (a, x1, y1, x2, y2) = |
y1 |
; a ≤ x1 |
y1 + (y2 -
y1) * z2*(3-2*z) |
; x1< a < x2 |
y2 |
; a ≥ x2 |
z
= |
((a - x1)/(x2 - x1)) |
Example
STEP(time, 1, 1, 2, 2) describes a smooth
step function of time with the value 1 before 1 second. This function incorporates
the cubic polynomial and levels off to the value 2 at 2 seconds.