burlap.domain.singleagent.cartpole.model

Class CPCorrectModel

java.lang.Object

burlap.domain.singleagent.cartpole.model.CPCorrectModel

All Implemented Interfaces:

FullStateModel, SampleStateModel

public class CPCorrectModel
extends java.lang.Object
implements FullStateModel

Author:

James MacGlashan.

Nested Class Summary

Nested classes/interfaces inherited from interface burlap.mdp.singleagent.model.statemodel.FullStateModel

FullStateModel.Helper

Field Summary

Fields

Modifier and Type	Field and Description
protected CartPoleDomain.CPPhysicsParams	physParams

Constructor Summary

Constructors

Constructor and Description
CPCorrectModel(CartPoleDomain.CPPhysicsParams physParams)

Method Summary

Modifier and Type	Method and Description
protected double	getAngle2ndDeriv(double xv0, double a0, double av0, double nsign, double f) Computes the 2nd order derivative of the angle for a given normal force sign using the corrected model.
protected double	getNormForce(double a0, double av0, double a_2) Computes the normal force for the corrected model
protected double	getX2ndDeriv(double xv0, double a0, double av0, double n, double f, double a2) Returns the second order x position derivative for the corrected model.
State	moveCorrectModel(State s, double dir) Simulates the physics for one time step give the input state s, and the direction of force applied.
State	sample(State s, Action a) Samples and returns a State from a state transition function.
java.util.List<StateTransitionProb>	stateTransitions(State s, Action a) Returns the set of possible transitions when Action is applied in State s.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

physParams

protected CartPoleDomain.CPPhysicsParams physParams

Constructor Detail

CPCorrectModel

public CPCorrectModel(CartPoleDomain.CPPhysicsParams physParams)

Method Detail

stateTransitions

public java.util.List<StateTransitionProb> stateTransitions(State s,
                                                            Action a)

Description copied from interface: FullStateModel

Returns the set of possible transitions when Action is applied in State s. The returned list only needs to include transitions that have non-zero probability of occurring.

Specified by:

stateTransitions in interface FullStateModel

Parameters:

s - the source state

a - the action to be applied in the source state

Returns:

the probability distribution of the state transition function specified as a list of StateTransitionProb objects.

sample

public State sample(State s,
                    Action a)

Description copied from interface: SampleStateModel

Samples and returns a State from a state transition function.

Specified by:

sample in interface SampleStateModel

Parameters:

s - the source state

a - the action to be executed in the source state

Returns:

a sample State

moveCorrectModel

public State moveCorrectModel(State s,
                              double dir)

Simulates the physics for one time step give the input state s, and the direction of force applied. The input state will be directly modified to be the next state. Physics simulated using one step of Euler's method on the corrected non-linear differential equations [1].

Parameters:

s - the current state from which one time step of physics will be simulated.

dir - the direction of force applied; should be -1, or 1 and is multiplied to this objects movementForceMag parameter. 0 would cause no force.

Returns:

the input state, which has been modified to the next state after one time step of simulation.

getAngle2ndDeriv

protected double getAngle2ndDeriv(double xv0,
                                  double a0,
                                  double av0,
                                  double nsign,
                                  double f)

Computes the 2nd order derivative of the angle for a given normal force sign using the corrected model.

Parameters:

xv0 - the cart velocity

a0 - the pole angle

av0 - the pole angle velocity

nsign - the normal force sign

f - the force applied to the cart

Returns:

the 2nd order derivative of the angle

getNormForce

protected double getNormForce(double a0,
                              double av0,
                              double a_2)

Computes the normal force for the corrected model

Parameters:

a0 - the pole angle

av0 - the pole angle velocity

a_2 - the 2nd order derivative of the pole angle

Returns:

the normal force

getX2ndDeriv

protected double getX2ndDeriv(double xv0,
                              double a0,
                              double av0,
                              double n,
                              double f,
                              double a2)

Returns the second order x position derivative for the corrected model.

Parameters:

xv0 - the cart velocity

a0 - the pole angle

av0 - the pole angle velocity

n - the normal force

f - the force applied to the cart

a2 - the second order angle derivative

Returns:

the second order x position derivative