TurtleMobility

simple module

A LOGO-style movement model, with the script coming from XML. It can be useful for describing random as well as deterministic scenarios.

First, a few examples.

Node(1,2) will move along a square's borders:

    <movement>
        <set speed="10" angle="180"/>
        <repeat n="4">
            <forward d="50"/>
            <turn angle="90"/>
        </repeat>
    </movement>

~MassMobility (in which the node is assumed to have a mass, and cannot turn abruptly):

    <movement>
        <repeat>
            <set speed="uniform(10,20)"/>
            <turn angle="uniform(-30,30)"/>
            <forward t="uniform(0.1,1)"/>
        </repeat>
    </movement>

~RandomWaypointMobility:

    <movement>
        <repeat>
            <set speed="uniform(20,60)"/>
            <moveto x="uniform($MINX,$MAXX)" y="uniform($MINY,$MAXY)"/>
        </repeat>
    </movement>

Commands (XML element names) are: repeat, set, forward, turn, wait, moveto, and moveby.

Accepted attributes:

repeat: n (optional)
set: x, y, speed, angle, borderPolicy (all optional)
forward: d, t (at least one of them must be present)
turn: angle (required)
wait: t (required)
moveto: x, y, t (all optional)
moveby: x, y, t (all optional)

Attribute values can be literal numbers (e.g. x="100"), or any distribution accepted in omnetpp.ini (e.g. speed="uniform(10,20)"). A new value will be chosen each time the statement is executed. The $MINX, $MAXX, $MINY and $MAXY strings will be substituted with the limits of the constraint area, respectively.

t is the time interval, calculated from the end of the previous movement. x, y are absolute coordinates with <set> and <moveto>, and relative with <moveby>. angle is clockwise in degrees, with 0 pointing west. d is distance in meters (speed is m/s).

borderPolicy controls what happens when a node reaches the edge of the constraint area and can take one of the values reflect, wrap, placerandomly. In the first case, the node reflects off the wall; with wrap, it'll come in on the other side (torus); and with placerandomly, it will be placed at a random position on the constraint area.

In addition to the node position, the module maintains two interval variables: speed and angle, which can be adjusted by <set> and <turn>. The <forward> statement, if only t or d is given, uses the speed variable. If you specify d and t together, that determines the speed as well, so the speed variable will be completely ignored.

Likewise, <moveto> and <moveby> will ignore the angle variable and will only use the speed variable if the t attribute is omitted.

If the repeat count n is omitted for the <repeat> statement, that means an infinite loop.

You can find the DTD with the sources: TurtleMobility.dtd.

Inheritance diagram

The following diagram shows inheritance relationships for this type. Unresolved types are missing from the diagram.

Extends

Name	Type	Description
MovingMobilityBase	simple module	Abstract base module for mobility models.

Parameters

Name	Type	Default value	Description
displayStringTextFormat	string	"p: %p\nv: %v"	Determines the text that is written on top of the submodule, supports displaying pars, watches, and module-specific information
subjectModule	string	"^"	The module path that determines the subject module, the motion of which this mobility model describes. The default value is the parent module
coordinateSystemModule	string	""	The module path of the geographic coordinate system module
updateDisplayString	bool	true	Enables continuous update of the subject module's position by modifying its display string
constraintAreaMinX	double	-inf m	The minimum x position of the constraint area. It is unconstrained by default (negative infinity)
constraintAreaMinY	double	-inf m	The minimum y position of the constraint area. It is unconstrained by default (negative infinity)
constraintAreaMinZ	double	-inf m	The minimum z position of the constraint area. It is unconstrained by default (negative infinity)
constraintAreaMaxX	double	inf m	The maximum x position of the constraint area. It is unconstrained by default (positive infinity)
constraintAreaMaxY	double	inf m	The maximum y position of the constraint area. It is unconstrained by default (positive infinity)
constraintAreaMaxZ	double	inf m	The maximum z position of the constraint area. It is unconstrained by default (positive infinity)
updateInterval	double	0.1s	The simulation time interval used to regularly signal mobility state changes and update the display
faceForward	bool	true
turtleScript	xml		Describes the movement

Properties

Name	Value	Description
class	TurtleMobility
display	i=block/cogwheel

Signals

Name	Type	Unit	Description
mobilityStateChanged	inet::MobilityBase		It works in inet, but not in the extended module in another namespace

Source code

//
// A LOGO-style movement model, with the script coming from XML. It can be
// useful for describing random as well as deterministic scenarios.
//
// First, a few examples.
//
// Node will move along a square's borders:
//
// <pre><nohtml>
//     <movement>
//         <set speed="10" angle="180"/>
//         <repeat n="4">
//             <forward d="50"/>
//             <turn angle="90"/>
//         </repeat>
//     </movement>
// </nohtml></pre>
//
// ~MassMobility (in which the node is assumed to have a mass, and cannot turn
// abruptly):
//
// <pre><nohtml>
//     <movement>
//         <repeat>
//             <set speed="uniform(10,20)"/>
//             <turn angle="uniform(-30,30)"/>
//             <forward t="uniform(0.1,1)"/>
//         </repeat>
//     </movement>
// </nohtml></pre>
//
// ~RandomWaypointMobility:
//
// <pre><nohtml>
//     <movement>
//         <repeat>
//             <set speed="uniform(20,60)"/>
//             <moveto x="uniform($MINX,$MAXX)" y="uniform($MINY,$MAXY)"/>
//         </repeat>
//     </movement>
// </nohtml></pre>
//
// Commands (XML element names) are: `repeat`, `set`, `forward`, `turn`, `wait`,
// `moveto`, and `moveby`.
//
// Accepted attributes:
//    - `repeat`: `n` (optional)
//    - `set`: `x`, `y`, `speed`, `angle`, `borderPolicy` (all optional)
//    - `forward`: `d`, `t` (at least one of them must be present)
//    - `turn`: `angle` (required)
//    - `wait`: `t` (required)
//    - `moveto`: `x`, `y`, `t` (all optional)
//    - `moveby`: `x`, `y`, `t` (all optional)
//
// Attribute values can be literal numbers (e.g. `x="100"`), or any
// distribution accepted in omnetpp.ini (e.g. `speed="uniform(10,20)"`).
// A new value will be chosen each time the statement is executed.
// The `$MINX`, `$MAXX`, `$MINY` and `$MAXY` strings will be substituted with the
// limits of the constraint area, respectively.
//
// `t` is the time interval, calculated from the end of the previous movement.
// `x`, `y` are absolute coordinates with `<set>` and `<moveto>`, and relative
// with `<moveby>`. `angle` is clockwise in degrees, with 0 pointing west.
// `d` is distance in meters (speed is m/s).
//
// `borderPolicy` controls what happens when a node reaches the edge of the
// constraint area and can take one of the values `reflect`, `wrap`,
// `placerandomly`. In the first case, the node reflects off the wall;
// with `wrap`, it'll come in on the other side (torus); and with
// `placerandomly`, it will be placed at a random position on the
// constraint area.
//
// In addition to the node position, the module maintains two interval variables:
// speed and angle, which can be adjusted by `<set>` and `<turn>`.
// The `<forward>` statement, if only `t` or `d` is given, uses the speed variable.
// If you specify `d` and `t` together, that determines the speed as well,
// so the speed variable will be completely ignored.
//
// Likewise, `<moveto>` and `<moveby>` will ignore the `angle` variable
// and will only use the speed variable if the `t` attribute is omitted.
//
// If the repeat count `n` is omitted for the `<repeat>` statement, that
// means an infinite loop.
//
// You can find the DTD with the sources: TurtleMobility.dtd.
//
simple TurtleMobility extends MovingMobilityBase
{
    parameters:
        xml turtleScript; // Describes the movement
        @class(TurtleMobility);
}

File: src/inet/mobility/single/TurtleMobility.ned