Documentation

phased.Platform System object

Package: phased

Motion platform

Description

The phased.Platform System object™ models the translational motion of one or more targets, sources, or receivers in space. The model assumes that the translational motion is always at constant velocity.

To model a moving platform:

  1. Define and set up your platform. See Construction.

  2. Call step to move the platform following a defined path according to the properties of phased.Platform. The behavior of step is specific to each object in the toolbox.

Construction

H = phased.Platform creates a platform System object, H. The object models translational motion in space.

H = phased.Platform(Name,Value) creates object, H, with each specified property Name set to the specified Value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).

H = phased.Platform(POS,V,Name,Value) creates a platform object, H, with the InitialPosition property set to POS, the Velocity property set to V, and other specified property Names set to the specified Values. POS and V are value-only arguments. To specify a value-only argument, you must also specify all preceding value-only arguments. You can specify name-value pair arguments in any order.

Properties

InitialPosition

Initial position of platform

Specify the initial position of the platform as a 3-by-1 real-valued column vector in the form of [x;y;z] or a 3-by-N real-valued matrix with each column taking the form [x;y;z]. The dimension N is the number of platforms. Position units are meters.

Default: [0;0;0]

Velocity

Velocity of platform

Specify the current velocity of the platform as a 3-by-1 real-valued column vector in the form of [vx;vy;vz] or a 3-by-N real-valued matrix with each column taking the form [vx;vy;vz]. The dimension N is the number of platforms. Velocity units are meters per second.

This property is tunable.

Default: [0;0;0]

OrientationAxes

Orientation axes of platform

Specify the three axes that define a local xyz coordinate systems for each platform as a 3-by-3 real-valued matrix for a single platform or as a 3-by-3-by-N real-valued matrix for multiple platforms. The dimension N is the number of platforms to model. For each platform, a column of the matrix represents a different axis of the coordinates system. The three axes must be orthonormal.

Default: [1 0 0;0 1 0;0 0 1]

OrientationAxesOutputPort

Output orientation axes

To obtain the orientation axes of the platform, set this property to true and use the corresponding output argument when invoking step. If you do not want to obtain the orientation axes of the platform, set this property to false.

Default: false

Methods

cloneCreate platform object with same property values
getNumInputsNumber of expected inputs to step method
getNumOutputsNumber of outputs from step method
isLockedLocked status for input attributes and nontunable properties
releaseAllow property value and input characteristics changes
resetReset platform to initial position
stepOutput current position, velocity, and orientation axes of platform

Examples

collapse all

Simulate motion of a platform

Create a platform at the origin having a velocity of (100,100,0) meters per second. Simulate the motion of the platform for two time steps, assuming the time elapsed for each step is one second. The position of the platform is updated after each step.

sPlat = phased.Platform([0; 0; 0],[100; 100; 0]);
T = 1;

At the first call to step, the position is at its initial value.

[pos,v] = step(sPlat,T);
pos
pos =

     0
     0
     0

At the second call to step, the position changes.

[pos,v] = step(sPlat,T);
pos
pos =

   100
   100
     0

Related Examples

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