WSF_POINT_MASS_SIX_DOF_MOVER

Derives From: WSF_SIX_DOF_MOVER

Script Class: WsfPointMassSixDOF_Mover

mover WSF_POINT_MASS_SIX_DOF_MOVER

mover <name> WSF_POINT_MASS_SIX_DOF_MOVER

   // PM6 Vehicle Type Commands
   vehicle_type ...

   ... WSF_SIX_DOF_MOVER Commands ...

   // Script Methods -- see WsfPointMassSixDOF_Mover

end_mover

Overview

WSF_POINT_MASS_SIX_DOF_MOVER is a specific type of WSF_SIX_DOF_MOVER, using simple, first-order force coefficients for translation, and effects-based control to carry out rotation.

In comparison to WSF_RIGID_BODY_SIX_DOF_MOVER, WSF_POINT_MASS_SIX_DOF_MOVER is less complicated to set up, requires less data, and is more numerically stable, but cannot reproduce the higher-order dynamics of a well-built WSF_RIGID_BODY_SIX_DOF_MOVER.

Unlike a “full” 6DOF model, the point-mass model only uses a scalar mass property, and is unaware of mass distribution and the resulting moment-of-inertia tensor. Rotation capabilities are defined in table data, and are modified during execution to account for vehicle mass and flight conditions such as angle-of-attack, and air density. Rotation from thrust vectoring is also imparted according to table data, with the thrust force vector held static.

Note

This limitation affects the construction of vertical-takeoff-and-landing vehicles. VTOL behavior can be approximated by including multiple engine instances in place of the same engine – one in takeoff-and-landing configuration, and one in position for navigation – and using script commands to ignite and shut-down the instances as appropriate.

WSF_POINT_MASS_SIX_DOF_MOVER does not support aerodynamic damping effects for either forces or rotation. Parameters are available for approximating static stability, but are not required.

PM6 Vehicle Type Commands

The most important command for a WSF_POINT_MASS_SIX_DOF_MOVER is vehicle_type, which defines the performance characteristics of of the object. The vehicle_type is defined as a point_mass_vehicle_type in a six_dof_object_types block. The vehicle_type must be defined before it is referenced in the mover WSF_POINT_MASS_SIX_DOF_MOVER block.

vehicle_type <string>

This defines the type of object used by the mover. The point-mass vehicle_type is defined in a six_dof_object_types block and must be defined before being referenced.

The simplest WSF_POINT_MASS_SIX_DOF_MOVER definition is something like this:

mover WSF_POINT_MASS_SIX_DOF_MOVER

vehicle_type F-15C

end_mover

This indicates that the F-15C vehicle_type will be used. F-15C must be a point_mass_vehicle_type – rigid_body_vehicle_type objects will not be accepted.

Script Methods

To learn about the various script methods supported by WSF_POINT_MASS_SIX_DOF_MOVER, see WsfPointMassSixDOF_Mover