NewGamePhysics.Physics.RotationalFrictionModel Class Reference

Model that simulates friction on a hinge (i.e. rotational friction) by reducing the angular velocity during the integration step. More...

List of all members.

Public Member Functions

 RotationalFrictionModel ()
 Create a friction model object and initialie the type to 'None'.
 RotationalFrictionModel (RotationalFrictionType f)
 Create a friction model object and initialie to the given type with some default parameters.
void SetNone ()
 Set the None friction type.
void SetLinear (double linearFrictionCoefficient)
 Set the Linear friction type.
void SetStribeck (double stribeckStaticFriction, double stribeckFrictionScale)
 Set the Stribeck friction type.
double ApplyFriction (double omega)
 Apply friction to a rotational element by changing the rotational speed.

Properties

double LinearFrictionCoefficient [get]
 Gets the linear friction coefficient for the linear friction model.
double StribeckStaticFriction [get]
 Gets the static friction coefficient for the Stribeck friction model.
double StribeckFrictionScale [get]
 Gets the scale coefficient for the Stribeck friction model.

Detailed Description

Model that simulates friction on a hinge (i.e. rotational friction) by reducing the angular velocity during the integration step.

Definition at line 38 of file FrictionModel.cs.

Constructor & Destructor Documentation

NewGamePhysics.Physics.RotationalFrictionModel.RotationalFrictionModel (  ) 

Create a friction model object and initialie the type to 'None'.

Definition at line 92 of file FrictionModel.cs.

00093         {
00094             this.frictionType = RotationalFrictionType.None;
00095         }

NewGamePhysics.Physics.RotationalFrictionModel.RotationalFrictionModel ( RotationalFrictionType  f  ) 

Create a friction model object and initialie to the given type with some default parameters.

Definition at line 101 of file FrictionModel.cs.

00102         {
00103             this.frictionType = f;
00104             switch (f)
00105             {
00106                 case RotationalFrictionType.Linear:
00107                     this.linearFrictionCoefficient = 0.0005;
00108                     break;
00109                 case RotationalFrictionType.Stribeck:
00110                     this.stribeckStaticFriction = 0.0001;
00111                     this.stribeckFrictionScale = 0.0002;
00112                     break;
00113             }
00114         }

Member Function Documentation

double NewGamePhysics.Physics.RotationalFrictionModel.ApplyFriction ( double  omega  ) 

Apply friction to a rotational element by changing the rotational speed.

Parameters:
omega Angular velocity without friction applied.
Returns:
Angular velocity after friction was applied.

Definition at line 150 of file FrictionModel.cs.

00151         {
00152             // Friction difference
00153             double deltaOmega = 0.0;
00154             double o = Math.Abs(omega);
00155 
00156             // Adjust by type
00157             switch (this.frictionType)
00158             {
00159                 case RotationalFrictionType.None:
00160                     // No friction
00161                     deltaOmega = 0.0;
00162                     break;
00163                 case RotationalFrictionType.Linear:
00164                     // Linear friction  
00165                     deltaOmega = linearFrictionCoefficient * o;
00166                     break;
00167                 case RotationalFrictionType.Stribeck:
00168                     // Stribeck friction
00169                     if (o < stribeckStaticFriction)
00170                     {
00171                         // Hinge stuck
00172                         return 0.0;
00173                     }
00174                     else
00175                     {
00176                         // Calculate friction as curve
00177                         deltaOmega = stribeckFrictionScale * (o - Math.Exp(-Math.Pow((o / 0.025), 0.3)) + Math.Pow(2.0 * o, (1 - 0.3)));
00178                     }
00179                     break;
00180             }
00181 
00182             // Handle discontinuity around zero
00183             if (omega > 0.0)
00184             {
00185                 omega -= deltaOmega;
00186                 if (omega < 0.0)
00187                 {
00188                     omega = 0.0;
00189                 }
00190             }
00191             else
00192             {
00193                 omega += deltaOmega;
00194                 if (omega > 0.0)
00195                 {
00196                     omega = 0.0;
00197                 }
00198             }
00199 
00200             return omega;
00201         }

void NewGamePhysics.Physics.RotationalFrictionModel.SetLinear ( double  linearFrictionCoefficient  ) 

Set the Linear friction type.

Definition at line 127 of file FrictionModel.cs.

00128         {
00129             this.frictionType = RotationalFrictionType.Linear;
00130             this.linearFrictionCoefficient = linearFrictionCoefficient;
00131         }

void NewGamePhysics.Physics.RotationalFrictionModel.SetNone (  ) 

Set the None friction type.

Definition at line 119 of file FrictionModel.cs.

00120         {
00121             this.frictionType = RotationalFrictionType.None;
00122         }

void NewGamePhysics.Physics.RotationalFrictionModel.SetStribeck ( double  stribeckStaticFriction,
double  stribeckFrictionScale 
)

Set the Stribeck friction type.

Parameters:
stribeckStaticFriction The Stribeck static friction coefficient.
stribeckFrictionScale The Stribeck friction scale.

Definition at line 138 of file FrictionModel.cs.

00139         {
00140             this.frictionType = RotationalFrictionType.Stribeck;
00141             this.stribeckStaticFriction = stribeckStaticFriction;
00142             this.stribeckFrictionScale = stribeckFrictionScale;
00143         }

Property Documentation

double NewGamePhysics.Physics.RotationalFrictionModel.LinearFrictionCoefficient [get]

Gets the linear friction coefficient for the linear friction model.

Definition at line 66 of file FrictionModel.cs.

double NewGamePhysics.Physics.RotationalFrictionModel.StribeckFrictionScale [get]

Gets the scale coefficient for the Stribeck friction model.

Definition at line 84 of file FrictionModel.cs.

double NewGamePhysics.Physics.RotationalFrictionModel.StribeckStaticFriction [get]

Gets the static friction coefficient for the Stribeck friction model.

Definition at line 75 of file FrictionModel.cs.

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