//Thirdparty Strings

Thirdparty strings allow any process to invoke a motion control task

The idea is that the Helm process subscribes to messages containing
 descriptions of a task to be executed. If the issuing process has been given
 explicit permission to execute this task in the Helms configuration block in the missions .moos file
the helm will invoke and manage the task.

The general format is as follows:

{JobName} @ {ClientProcessName}:TASK={TaskName}|{Param=Value}{..}....


For example imagine a program called iVoice wanted to run a task of type
"GoToWayPoint", one of the many tasks that the helm can execute. We choose to name this
task "T1". We would form the following string:


"T1@iVoice:TASK=GOTOWAYPOINT|NAME=GOTOWAYPOINT_1|PRIORITY=3|INITIALSTATE=ON|TIMEOUT=200|THRUST=6|LOCATION=10,10,0|RADIUS=1"

Everything after the "TASK=GOTOWAYPOINT" substring is a list of parameter value
pairs required by the task, in this case a task of type GOTOWAYPOINT. 

How do you know which parameters are required? Well, there is documentation on the MOOS web page
but it is perhaps easier to look at examples. Normaly tasks are written within {} blocks in
either a mission file (*.moos) or a task file *.hoof. The Thirdparty string is simply one of these
block laid out flat. For example the above string would appear as:

//this task moves towards a waypoint, when it reaches it the task
//finishes
Task = GotoWayPoint
{
	Name = GOTOWAYPOINT_1
	Priority = 3
	InitialState = ON
	TimeOut = 200
	Thrust = 6
	Location = 10,10,0
	Radius = 1	
}

Okay, with this in hand here are a few other useful task blocks


//This task turns towards a goal and then heads towards it. When
//a "location" is reached it turns its attention to the next location
//the whole pattern can be repeated:
Task = SteerThenDriveXYPattern
{
	Name = XY1
	Priority = 3

	//set this to on and task will go live instantly
	InitialState = ON

	//if task doesn't complete in this time task will stop
	TimeOut = 300
	
	//a flag that is written when the task ends
	FinishFlag = EndMission

	//if Initial state is not On task will only activate
	//when the followin flag is written by anothe task or process
	StartFlag = WP1Done

	//how fast do you wanna go (100 is 100 pc throttle)
	Thrust = 30

	//specify as many location way points as you like
	//the vehicle will visit all of them
	Location = 0,5,0
	Location = 5,5,0
	Location = 0,0,0

	//how close you wanna get to each point
	Radius = 0.4

	//how many times do you want to repeat?
	Repeat = 2

	//misc params
	ThrustDamping = 0.1;
	OuterYawLimit = 20
	InnerYawLimit = 5


}


//this task is similar to the above one only
//it does not turn to face the next location
//before translating
Task = XYPattern
{
	Name = XY1
	Priority = 3
	InitialState = ON
	TimeOut = 300
	FinishFlag = EndMission
	StartFlag = WP1Done
	Thrust = 70
	Location = 100,50,0
	Location = 20,50,0
	Radius = 10	
	Repeat = 2
}


//pretty obvious - orbits a given Location
Task = Orbit
{
	Name = ORBIT1
	Priority = 3
	InitialState = OFF
	TimeOut = 300
	FinishFlag = EndMission
	StartFlag = WP1Done
	Thrust = 40
	Location = 20,20,0
	Direction = CCW
	Radius = 40	
	Repeat = 2

	//how many points in a circle?
	TotalPos = 6

	//how close do you have to get 
	//to have reached one point on a circle?
	PosRadius = 5
}


//moves along a straight line between P1 and P2
//Initially vehicle moves towards line until it joins it
Task = TrackLine
{
	Name = East
	Priority = 3
	InitialState = ON
	TimeOut = 200
	FinishFlag = EndMission
	Thrust = 60
	P1 = 0,0,0
	P2 = 100,0,0
	Radius = 1	
	Lead = 1
}