HyperGraph

Vehicle Safety Tools - Math Menu

Vehicle Safety Tools - Math Menu

 Previous topic Next topic No expanding text in this topic  

Vehicle Safety Tools - Math Menu

 Previous topic Next topic JavaScript is required for expanding text JavaScript is required for the print function  

The vehicle safety tools' Math menu allows you to perform basic math operations on one, two, or three curves at a time.  The operations include curve addition and multiplication and resultants, for example.  The start, end, or sample frequency of the various curves is not an issue - the VST automatically crops and samples the input curves as needed.  The curves must be using the same units, in most cases.

The Math menu contains three secondary menus: one curve, two curves, and three curves.  Those secondary menus contain the following plot macros:

One Curve

Option

Description

Absolute

Given c1, a curve is created which is the absolute value of y vs. x.

Acoustic Weighting

 

Auto Correlation

If you are comparing two curves, this function would show where the curves match in phase, where c1 and c2 are the same curve.

Auto correlation between two curves.

Output

x: lag

y: correlation (A value of 1 is a perfect correlation)

This can be read as: At a lag of time "x", c1 and c2 have a correlation value of "y".

Derivative

Given c1, a curve is created that is the derivative of c1.

Double Integral

Given c1, a curve is created that is the double integral of c1.

Double Derivative

 

Duration

Calculates the load versus duration for a given curve.

Duration Comp

Partitions the input curve into 101 bins, reporting only the negative curve values.

Duration Tens

Partitions the input curve into 101 bins, reporting only on the positive curve values.

Integral

Given c1, calculates the integral of the c1.

Max Note

 

Min Note

 

Normalize

Given c1, calculates a new curve, such that the peak value is "1".

Normalize over Max

 

Resample or Sample Points

Resamples the given input curve to the specified data frequency.

Reverse Curve

Reverses a curve about the vertical axis, like a mirror.

Square

Calculates the square of the curve.

Window

Crops the curve to the given window size.

Window Integral

Given c1, calculates the integral of c1 over the range of the window.

Zero

Sets the y value in a given range to the user-defined constant.

g>>mph

Integrates acceleration curve to obtain velocity.

Input: g’s vs. seconds

Output: mph vs. seconds

g>>inch

Double integrates an acceleration curve (given in g’s and seconds) to a displacement (given in inches and seconds).

mph>>g

Given c1, a curve is created that is the derivative of velocity to acceleration, while converting MPH to g's.

Two Curves

Option

Description

Add

Adds two curves.

Average

Averages two curves.

Cross Correlation

Given c1 and c2, a curve is created which is the cross correlation between the y vectors of c1 and c2.

Cross correlation between two curves.

Output èè

x: lag

y: correlation (A value of 1 is a perfect correlation)

This can be read as: At a lag of time "x", c1 and c2 have a correlation value of "y".

Cross Plot

Given c1 and c2, this function plots c1.y as x and c2.y as y of a new curve.

Divide

Divides two curves.  If c2 has zero values, this will fail.

Divide with Zero

If c1 is divided by c2, and if c2 has any zero values, then c1/c2 equals 0.

Multiply

Multiplies two curves.

Resultant

Given c1 and c2, calculates the square root of (c12 + c22).

Subtract

Subtracts two curves.

Three Curves

Option

Description

Add

Adds three curves.

Average

Averages three curves.

Multiply

Multiplies three curves.

Resultant

Given c1, c2, and c3, calculates the square root of (c12 + c22+c32).