SensorObject

A sensor attached to an object other than a body - a connector, a constraint, a joint - which measures one of the output variables of the object; a body is measured at a point, with SensorBody.

Parameters

The parameters of the item; in a dictionary, its type is ‘Object’:

name	type	size	default	description
name	String		‘’	sensor’s unique name
objectNumber	ObjectIndex		invalid (-1)	object (e.g. connector) number to which sensor is attached to
writeToFile	Bool		True	True: write sensor output to file; flag is ignored (interpreted as False), if fileName=’’
fileName	String		‘’	directory and file name for sensor file output; empty: no file is written; a relative name is placed in exudyn.config.outputDirectory if that is set; the directory is created if it does not exist
outputVariableType	OutputVariableType		OutputVariableType::_None	OutputVariableType for sensor
storeInternal	Bool		False	true: store sensor data in memory (faster, but may consume large amounts of memory); false: internal storage not available
visualization	VSensorObject			parameters for visualization of item

Visualization parameters

The parameters of VSensorObject, given as visualization:

name	type	size	default	description
show	Bool		True	set true, if item is shown in visualization and false if it is not shown; sensors can be shown at the position assiciated with the object - note that in some cases, there might be no such position (e.g. data object)!

Drawing

Drawn as all sensors.

Detailed description

Attached to

The object objectNumber, usually a connector, constraint or joint, which is measured as a whole and not at a point.

Measures

outputVariableType is one of the output variables of the object, as its page lists them under Output variables - for a spring-damper e.g. Force and Distance, for a joint the reaction forces and torques in the frame its page gives.

Mini example

#the force in a spring-damper, measured at the object
node = mbs.AddNode(NodePoint(referenceCoordinates=[1,0,0]))
mbs.AddObject(ObjectMassPoint(nodeNumber=node, mass=1))
mNode = mbs.AddMarker(MarkerNodePosition(nodeNumber=node))
mFixed = mbs.AddMarker(MarkerNodePosition(nodeNumber=nGround))
oSpring = mbs.AddObject(ObjectConnectorSpringDamper(markerNumbers=[mFixed, mNode], stiffness=100, referenceLength=1))
mbs.AddObject(ObjectConnectorCartesianSpringDamper(markerNumbers=[mFixed, mNode], stiffness=[0,100,100],
                                                   offset=[1,0,0])) #holds y and z
mbs.AddLoad(LoadForceVector(markerNumber=mNode, loadVector=[10,0,0]))
sForce = mbs.AddSensor(SensorObject(objectNumber=oSpring, outputVariableType=exu.OutputVariableType.Force,
                                    storeInternal=True, writeToFile=False))

mbs.Assemble()
mbs.SolveStatic()

#the spring force equals the load
exu.sys['testResult'] = mbs.GetSensorValues(sForce)[0] #10

Examples (Ex) and TestModels (TM) that show this item, with weblink to github: tutorialSpringDamper.py (Ex), tutorialSpringDamperCreate.py (Ex), pendulum2Dconstraint.py (Ex), plotSensorExamples.py (Ex)