perturbations

Perturbation defined on object

Syntax

perturbs = perturbations(obj)

perturbs = perturbations(obj,property)

perturbs = perturbations(obj,property,'None')

perturbs = perturbations(obj,property,'Selection',values,probabilities)

perturbs = perturbations(obj,property,'Normal',mean,deviation)

perturbs = perturbations(obj,property,'Uniform',minVal,maxVal)

perturbs = perturbations(obj,property,'Custom',perturbFcn)

Description

perturbs = perturbations(obj) returns the list of property perturbations, perturbs, defined on the object, obj. The returned perturbs lists all the perturbable properties. If any property is not perturbed, then its corresponding Type is returned as "Null" and its corresponding Value is returned as {Null,Null}.

perturbs = perturbations(obj,property) returns the current perturbation applied to the specified property.

perturbs = perturbations(obj,property,'None') defines a property that must not be perturbed.

perturbs = perturbations(obj,property,'Selection',values,probabilities) defines the property perturbation offset drawn from a set of values that have corresponding probabilities.

perturbs = perturbations(obj,property,'Normal',mean,deviation) defines the property perturbation offset drawn from a normal distribution with specified mean and standard deviation.

perturbs = perturbations(obj,property,'Uniform',minVal,maxVal) defines the property perturbation offset drawn from a uniform distribution on an interval [minVal, maxValue].

perturbs = perturbations(obj,property,'Custom',perturbFcn) enables you to define a custom function, perturbFcn, that draws the perturbation offset value.

Examples

Perturb Accuracy of insSensor

Create an insSensor object.

sensor = insSensor

sensor = 
  insSensor with properties:

           MountingLocation: [0 0 0]                 
               RollAccuracy: 0.2                deg  
              PitchAccuracy: 0.2                deg  
                YawAccuracy: 1                  deg  
           PositionAccuracy: [1 1 1]            m    
           VelocityAccuracy: 0.05               m/s  
       AccelerationAccuracy: 0                  m/s² 
    AngularVelocityAccuracy: 0                  deg/s
                  TimeInput: 0                       
               RandomStream: 'Global stream'         

Define the perturbation on the RollAccuracy property as three values with an equal possibility each.

values = {0.1 0.2 0.3}

values=1×3 cell array
    {[0.1000]}    {[0.2000]}    {[0.3000]}

probabilities = [1/3 1/3 1/3]

probabilities = 1×3

    0.3333    0.3333    0.3333

perturbations(sensor,'RollAccuracy','Selection',values,probabilities)

ans=7×3 table
            Property                Type                        Value                 
    _________________________    ___________    ______________________________________

    "RollAccuracy"               "Selection"    {1x3 cell}    {[0.3333 0.3333 0.3333]}
    "PitchAccuracy"              "None"         {[   NaN]}    {[                 NaN]}
    "YawAccuracy"                "None"         {[   NaN]}    {[                 NaN]}
    "PositionAccuracy"           "None"         {[   NaN]}    {[                 NaN]}
    "VelocityAccuracy"           "None"         {[   NaN]}    {[                 NaN]}
    "AccelerationAccuracy"       "None"         {[   NaN]}    {[                 NaN]}
    "AngularVelocityAccuracy"    "None"         {[   NaN]}    {[                 NaN]}

Perturb the sensor object using the perturb function.

rng(2020)
perturb(sensor);
sensor

sensor = 
  insSensor with properties:

           MountingLocation: [0 0 0]                 
               RollAccuracy: 0.5                deg  
              PitchAccuracy: 0.2                deg  
                YawAccuracy: 1                  deg  
           PositionAccuracy: [1 1 1]            m    
           VelocityAccuracy: 0.05               m/s  
       AccelerationAccuracy: 0                  m/s² 
    AngularVelocityAccuracy: 0                  deg/s
                  TimeInput: 0                       
               RandomStream: 'Global stream'         

The RollAccuracy is perturbed to 0.5 deg.

Input Arguments

obj — Object to be perturbed

objects

Object to be perturbed, specified as an object. The objects that you can perturb include:

• insSensor

property — Perturbable property

property name

Perturbable property, specified as a property name. Use perturbations to obtain a full list of perturbable properties for the specified obj.

values — Perturbation offset values

n-element cell array of property values

Perturbation offset values, specified as an n-element cell array of property values. The function randomly draws the perturbation value for the property from the cell array based on the values' corresponding probabilities specified in the probabilities input.

probabilities — Drawing probabilities for each perturbation value

n-element array of nonnegative scalar

Drawing probabilities for each perturbation value, specified as an n-element array of nonnegative scalars, where n is the number of perturbation values provided in the values input. The sum of all elements must be equal to one.

For example, you can specify a series of perturbation value-probability pair as {x1,x2,…,xn} and {p1,p2,…,pn}, where the probability of drawing xi is pi (i = 1, 2, …,n).

mean — Mean of normal distribution

scalar | vector | matrix

Mean of normal distribution, specified as a scalar, vector, or matrix. The dimension of mean must be compatible with the corresponding property that you perturb.

deviation — Standard deviation of normal distribution

nonnegative scalar | vector of nonnegative scalar | matrix of nonnegative scalar

Standard deviation of normal distribution, specified as a nonnegative scalar, vector of nonnegative scalars, or matrix of nonnegative scalars. The dimension of deviation must be compatible with the corresponding property that you perturb.

minVal — Minimum value of uniform distribution interval

scalar | vector | matrix

Minimum value of the uniform distribution interval, specified as a scalar, vector, or matrix. The dimension of minVal must be compatible with the corresponding property that you perturb.

maxVal — Maximum value of uniform distribution interval

scalar | vector | matrix

Maximum value of the uniform distribution interval, specified as a scalar, vector, or matrix. The dimension of maxVal must be compatible with the corresponding property that you perturb.

perturbFcn — Perturbation function

function handle

Perturbation function, specified as a function handle. The function must have this syntax:

offset = myfun(propVal)

where propVal is the value of the property and offset is the perturbation offset for the property.

Output Arguments

perturbs — Perturbations defined on object

table of perturbation property

Perturbations defined on the object, returned as a table of perturbation properties. The table has three columns:

• Property — Property names.

• Type — Type of perturbations, returned as "None", "Selection", "Normal", "Uniform", or "Custom".

• Value — Perturbation values, returned as a cell array.