length of pendulum rod
radius of rigid body pendulum disk
starting angle for the pendulum; in radians; zero is straight down; counter-clockwise is positive
Optional opt_name: stringname of this as a Subject
Optional opt_simList: SimListSimList to use (optional)
Protected initialInitial values.
Private radius_radius of rigid body pendulum disk
Adds the given Observer to this Subject's list of Observers, so that the Observer
will be notified of changes in this Subject. An Observer may call Subject.addObserver
during its observe method.
the Observer to add
Adds the Parameter to the list of this Subject's available Parameters.
the Parameter to add
if a Parameter with the same name already exists.
Notifies all Observers that this Subject has changed by calling observe on each Observer.
An Observer may call addObserver or removeObserver during its observe
method.
a SubjectEvent with information relating to the change
Notifies all Observers that the Parameter with the given name has changed by calling observe on each Observer.
the language-independent or English name of the Parameter that has changed
if there is no Parameter with the given name
Defines the differential equations of this ODESim; for an input set of variables, returns the current rate of change for each variable (the first derivative of each variable with respect to time).
The timeStep is the time since the state variables were last fully calculated, which
can be and often is zero. The current time can be regarded as getTime() + timeStep.
The input variables correspond to the Simulation state at that time. Note that
timeStep is different from the time step used to advance the Simulation (as in
AdvanceStrategy.advance).
The timeStep is typically used when finding collisions in
CollisionSim.findCollisions.
the current array of state variables (input),
corresponding to the state at getTime() + timeStep
array of change rates for each variable (output), all values are zero on entry.
the current time step (might be zero)
null if the evaluation succeeds, otherwise an object relating to the
error that occurred. The change array contains the output results.
Protected getReturns whether broadcasting is enabled for this Subject. See setBroadcast.
whether broadcasting is enabled for this Subject
Returns the current EnergyInfo for this system.
an EnergyInfo object representing the current energy of this system.
Returns the ParameterBoolean with the given name.
the language-independent or English name of the ParameterBoolean
the ParameterBoolean with the given name
if there is no ParameterBoolean with the given name
Returns the ParameterNumber with the given name.
the language-independent or English name of the ParameterNumber
the ParameterNumber with the given name
if there is no ParameterNumber with the given name
Returns the ParameterString with the given name.
the language-independent or English name of the ParameterString
the ParameterString with the given name
if there is no ParameterString with the given name
Private moveRemoves the Observer from this Subject's list of Observers. An Observer may
call removeObserver during its observe method.
the Observer to detach from list of Observers
Removes the Parameter from the list of this Subject's available Parameters.
the Parameter to remove
Sets the Simulation back to its initial conditions, see saveInitialState, and calls modifyObjects. Broadcasts event named 'RESET'.
Restores the Simulation state that was saved with saveState.
Saves the current variables and time as the initial state, so that this initial state can be restored with reset. Broadcasts event named 'INITIAL_STATE_SAVED'.
Saves the current state of the Simulation, so that we can back up to this state later on. The state is defined mainly by the set of Simulation variables, see getVarsList, but can include other data. This state is typically used for collision detection as the before collision state, see CollisionSim.findCollisions.
Protected setSets whether this Subject will broadcast events, typically used to temporarily disable broadcasting. Intended to be used in situations where a subclass overrides a method that broadcasts an event. This allows the subclass to prevent the superclass broadcasting that event, so that the subclass can broadcast the event when the method is completed.
whether this Subject should broadcast events
the previous value
Sets the Terminal object that this simulation can print data into.
the Terminal object that this simulation can print data into.
Protected setSets the VarsList for this simulation.
the VarsList to use in this simulation
Private showReturns a minimal string representation of this object, usually giving just identity information like the class name and name of the object.
For an object whose main purpose is to represent another Printable object, it is
recommended to include the result of calling toStringShort on that other object.
For example, calling toStringShort() on a DisplayShape might return something like
this:
DisplayShape{polygon:Polygon{'chain3'}}
a minimal string representation of this object.
Generated using TypeDoc
Single pendulum done with reaction forces instead of the analytic equations of motion as in PendulumSim. This is similar to how the rigid body physics engine in ContactSim calculates forces, but this is specific to only this particular single pendulum scenario.
The pendulum is regarded as a rigid body consisting of a uniform disk at end of a massless rigid arm. We find the reaction forces by solving a matrix equation, following the steps shown at https://www.myphysicslab.com/contact.html.
Variables
The pivot is fixed at the origin.
(x,y)= center of diskw= angle of pendulumNote that
wis the angle of the pendulum in relation to the pivot point, which happens to also correspond to the angle of the disk rigid body (perhaps adding a constant).TO DO make dragable for setting start angle?