Motion Platform
Moving platform.
Description
The Motion Platform block simulates the motion of multiple platforms such as aircraft, ground vehicles and/or transceiver arrays by determining their position and velocity. Platforms move along trajectories defined by initial positions and velocities, depending on the selected motion model, either velocity or acceleration. The positions and velocities of the platforms are updated at each simulation step. In addition, you can set the initial orientations of the platforms and receive orientation updates.
Ports
Input
Ref - input value of reference time
scalar
Input value of the reference time. The unit of measurement is seconds.
Dependencies
To use this port, set the Source of elapsed simulation time parameters to Derive from reference input port.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.
Vel is the input velocity of the platform
real matrix 3 by N
Platform velocity given as a real matrix 3 by N, where N is the number of platforms to be modelled. The units of measurement are metres per second.
Dependencies
To use this port, set the Model of object motion parameters to Velocity and the Source of velocity parameters to Input port.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.
Acl - platform acceleration
real matrix 3 by N
Platform acceleration given as a real matrix 3 by N, where N is the number of platforms to be modelled. Units are metres per second squared.
Dependencies
To use this port, set the Model of object motion parameters to Acceleration and the Source of acceleration parameters to Input port.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.
Output
Pos - platform position
real matrix 3 by N
Current platform position returned as a real matrix 3 by N, where N is the number of platforms to be modelled. The units of measurement are metres.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.
Vel - output speed of the platform
real matrix 3 by N
Current platform speed returned as a real matrix 3 by N, where N is the number of platforms to be modelled. The units are metres per second.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.
LAxes - platform orientation axes
real matrix 3 by 3 by N
The current platform orientation axes returned as a 3 by 3 by N real matrix, where N is the number of platforms to be modelled. Each 3 by 3 submatrix is an orthogonal matrix. This output is enabled when the OrientationAxesOutputPort parameters are set to true. The current axes of the platform rotate around the normal vector to the platform trajectory.
Dependencies
To use this port, select the Enable orientation axes output checkbox.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.
Parameters
Model of object motion - model of object motion
Velocity (by default) | Acceleration | Custom
Specify the object motion model as Velocity, Acceleration or Custom.
When the parameters is set to Velocity, the platform moves along the trajectory with constant speed at each simulation step.
When the parameters is set to Acceleration, the platform moves along the trajectory with constant acceleration at each simulation step.
When the parameter is set to `Custom', the platform moves along a sequence of waypoints specified by the Custom trajectory waypoints parameter. To obtain position and velocity at each time step, the object performs piecewise cubic interpolation over the waypoints.
Initial position (m) - initial position of the platform
[0;0;0] (by default)
Initial position of the platform in metres as a 3 by N matrix, where each column represents the initial position of the platform as [x;y;z]. The number N is the number of platforms.
Initial velocity (m/s) is the initial velocity of the platform
[0;0;0] (by default)
Initial velocity of the platform (in m/s), in the form of a matrix of size 3 by N, where each column represents the initial velocity of the platform in the form [vx;vy;vz]. The number N is the number of platforms.
Dependencies
This parameter is used if the parameters Source of velocity or Source of acceleration are set to Input port.
Source of velocity is the source of velocity data
Property (By default) | Input port.
This parameter is only used when the Model of object motion parameter is set to Velocity. In this case, velocity data must be provided for the model. Specify Property or Input port as the source of velocity data.
Velocity (m/s) - current platform speed
[0;0;0] (by default)
Current platform velocity (in m/s), in the form of a matrix of size 3 by N, where each column represents the initial velocity of the platform in the form [vx;vy;vz]. Number N is the number of platforms.
Dependencies
This parameter is used if the Model of object motion parameter is set to Velocity and the Source of velocity parameter is set to Property.
Source of acceleration is the source of acceleration data
Property (By default) | Input port
This parameter is only used when the Model of object motion parameter is set to Acceleration. In this case, acceleration data must be provided for the model. Specify Property or Input port as the source of acceleration data.
Acceleration (m/s^2) - current acceleration
[0;0;0] (By default)
Current acceleration (in m/s2), as a matrix of size 3 by N, where each column represents the initial velocity of the platform as [ax;ay;az]. The number N is the number of platforms.
Dependencies
This parameter is used if the Model of object motion parameter is set to Acceleration and the Source of acceleration parameter is set to Property.
Custom trajectory waypoints - trajectory waypoints
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0; 1, 0, 0, 0, 0, 0, 0, 0, 0 ] (by default).
The waypoints of the trajectory given as a real matrix M by L or an array M by L by N. M is the number of waypoints. L - 4 or 7.
If L is 4, the first column specifies the time points at which the platform position is measured. Columns 2 - 4 are position measurements in x, y and z coordinates. The velocity is determined from the position measurements.
If L is 7, then columns 5 - 7 of the matrix are velocity measurements in x, y and z coordinates.
When the Custom trajectory waypoints parameter is set to a 3D array value, the number of pages, N, represents the number of platforms.
Time units are seconds, position units are metres, and velocity units are metres per second.
Dependencies
This parameter is used when the Model of object motion parameter is set to Custom.
Mechanical scanning mode - mechanical scanning mode
None (by default) | Circular | Sector.
Mechanical scanning mode for the platform, set as None, Circular or Sector, where None is the value by default.
When the Mechanical scanning mode parameters are set to Circular, the platform continuously scans clockwise 360 degrees in the azimuth direction of the platform orientation axes.
When the Mechanical scanning mode parameter is set to Sector, the platform scans clockwise in the azimuth direction of the platform orientation axes within the range specified by the Azimuth scan angle span (deg) parameter. When the platform scan reaches the range boundary, the scan reverses direction and returns to another scan boundary. Scanning takes place within the platform orientation axes.
Initial scan angle (deg) - initial scan angle of the platform
`0 (By default)
Initial scan angle of the platform, specified as a vector 1 by N, where N is the number of platforms.
Scanning is performed in the local coordinate system of the platform. Parameters Initial orientation axes sets the initial local coordinate system. At the beginning of the simulation the orientation axes specified by the Initial orientation axes parameter are rotated by the angle specified in the Initial scan angle (deg) parameter. The value by default is zero. The units of measurement are degrees.
Dependencies
This parameter is used when the Mechanical scanning mode parameters are set to Circular or Sector.
Azimuth scan angle span (deg) - azimuth scan angle range
[-60,60] (By default).
Azimuth scan angle range specified as a matrix N by 2, where N is the number of platforms.
Each row of the matrix specifies the scanning range of the corresponding platform in the form of [ScanAngleLowerBound ScanAngleHigherBound]. By default, the value [-60 60] is used. The units of measurement are degrees.
Dependencies
This parameter is used when the Mechanical scanning mode parameter is set to Sector.
Azimuth scan rate (deg/s) - azimuth scan rate
10 (By default).
Azimuth scan rate, specified as a vector 1 by N, where N is the number of platforms.
Each entry in the vector is the azimuth scanning speed for the corresponding platform. By default, the value is 10 deg/sec. The units of measurement are degrees/second.
Dependencies
This parameter is used when the Mechanical scanning mode parameters are set to Circular or Sector.
Initial orientation axes - initial orientation axes of the platform
eye(3) (by default).
Three axes defining the initial local (x,y,z) coordinate system of the platform, in the form of a 3 by 3 by N matrix. Each column of the matrix represents an axis of the local coordinate system. All three axes must be orthogonal.
Enable orientation axes output - output of orientation axes
` disabled (by default)` | enabled
Select this checkbox to receive instantaneous platform orientation axes through the LAxes output port.
The port only appears when the checkbox is selected.
Source of elapsed simulation time - source of elapsed simulation time
Auto (by default) | Derive from reference input port.
Specify Auto or Derive from reference input port as the source of simulation time.
When Auto is selected, the block calculates the elapsed time.
When Derive from reference input port is selected, the unit uses the duration of the reference signal applied to the Ref input port.
Inherit sample rate - inherit sample rate
On (By default) | Off
Select the checkbox to inherit sample rate from upstream blocks. Otherwise, set the sample rate using the Sample rate (Hz) parameters.
Sample rate (Hz) - sampling rate
1e6 (By default) | positive scalar.
The sampling frequency of the signal as a positive scalar. The unit of measurement is Hz.
Dependencies
To use this parameters, clear the Inherit sample rate checkbox.
Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool.