Switch operations based on state?

[patrickwalton]

I see in the flyby scenario that you can switch between operations by starting and stopping the simulation. Is there a way to switch operations based on state? For example, I'd like to have a despin process that runs until the gyros drop below a certain number, after which the simulation switches into a pointing process.

[joaogvcarneiro]

You can write a Python module that takes in the information you need to make a decision and then change the flight mode accordingly. See scenarioAttitudePointingPy for details on Python modules. Please note that the way Python modules are integrated is changing. See PR #239, and issues #200 and #209 for details.

[patrickwalton]

Here's what I came up with. It feels a little hacky passing modules into another module like this, but it works.

class modeSelector(simulationArchTypes.PythonModelClass):

    def __init__(self, modelName, modelActive=True, modelPriority=-1, sim=None, task=None):
        super(modeSelector, self).__init__(modelName, modelActive, modelPriority)

        # Initialize dictionary of dependent modules
        self.sim = sim
        self.task = task

        self.eclipse = False

        # Input messages
        self.cssConstInMsg = messaging.CSSArraySensorMsgReader()
        # self.cssConstConfigInMsg = messaging.CSSConfigMsgReader() TODO: submit issue to modify to include minOutput

    def reset(self, currentTime):

        return

    def updateState(self, currentTime):
        
        # read input messages
        CSSMsg = self.cssConstInMsg()
        # CSSConfigMsg = self.cssConstConfigInMsg()
        
        # Use CSS to determine whether we are in Eclipse
        CSSMsgData = CSSMsg.CosValue
        if any([v > 0.1 for v in CSSMsgData]):
            self.eclipse = False
        else:
            self.eclipse = True

        # Enable/disable tasks based on state.
        if self.eclipse:
            self.sim.disableTask(self.task)
        else:
            self.sim.enableTask(self.task)

        return

[joaogvcarneiro]

I'm not sure what you mean by

passing modules into another module

It looks like you're making use of the messaging system to take information in (although some lines are commented out). This looks like the correct approach.

If you want flight modes to do multiple things, I'd suggest looking at creating events. See examples/BskSim/models/BSK_Fsw. Lines 133-190 create multiple modes that can be changed by changing the value of a single variable. Might be useful.

[patrickwalton]

By "passing modules" I meant that I have to pass a handle for "scSim" (sim in init arguments) rather than connecting it via message, because I need to alter scSim's configuration itself (by enabling/disabling one of its tasks), which I assume is not possible via message.