This information is part of the Modelica Standard Library maintained by the Modelica Association.

# Body

Rigid body with mass, inertia tensor and one frame connector (12 potential states)

CONNECTORS

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Name | Type | Description | |
---|---|---|---|

frame_a | Frame_a | Coordinate system fixed at body |

PARAMETERS

Name | Type | Default Value | Description |
---|---|---|---|

animation | Boolean | true | = true, if animation shall be enabled (show cylinder and sphere) |

r_CM | Position[3] | Vector from frame_a to center of mass, resolved in frame_a | |

m | Mass | Mass of rigid body | |

I_11 | Inertia | 0.001 | (1,1) element of inertia tensor |

I_22 | Inertia | 0.001 | (2,2) element of inertia tensor |

I_33 | Inertia | 0.001 | (3,3) element of inertia tensor |

I_21 | Inertia | 0 | (2,1) element of inertia tensor |

I_31 | Inertia | 0 | (3,1) element of inertia tensor |

I_32 | Inertia | 0 | (3,2) element of inertia tensor |

angles_fixed | Boolean | false | = true, if angles_start are used as initial values, else as guess values |

angles_start | Angle[3] | {0,0,0} | Initial values of angles to rotate frame_a around 'sequence_start' axes into frame_b |

sequence_start | RotationSequence | {1,2,3} | Sequence of rotations to rotate frame_a into frame_b at initial time |

w_0_fixed | Boolean | false | = true, if w_0_start are used as initial values, else as guess values |

w_0_start | AngularVelocity[3] | {0,0,0} | Initial or guess values of angular velocity of frame_a resolved in world frame |

z_0_fixed | Boolean | false | = true, if z_0_start are used as initial values, else as guess values |

z_0_start | AngularAcceleration[3] | {0,0,0} | Initial values of angular acceleration z_0 = der(w_0) |

sphereDiameter | Diameter | world.defaultBodyDiameter | Diameter of sphere |

cylinderDiameter | Diameter | sphereDiameter/Types.Defaults.BodyCylinderDiameterFraction | Diameter of cylinder |

enforceStates | Boolean | false | = true, if absolute variables of body object shall be used as states (StateSelect.always) |

useQuaternions | Boolean | true | = true, if quaternions shall be used as potential states otherwise use 3 angles as potential states |

sequence_angleStates | RotationSequence | {1,2,3} | Sequence of rotations to rotate world frame into frame_a around the 3 angles used as potential states |

I | Inertia[3,3] | [I_11,I_21,I_31;I_21,I_22,I_32;I_31,I_32,I_33] | inertia tensor |

R_start | Orientation | Modelica.Mechanics.MultiBody.Frames.axesRotations(sequence_start, angles_start, zeros(3)) | Orientation object from world frame to frame_a at initial time |

z_a_start | AngularAcceleration[3] | Frames.resolve2(R_start, z_0_start) | Initial values of angular acceleration z_a = der(w_a), i.e., time derivative of angular velocity resolved in frame_a |

Q_start | Orientation | Frames.to_Q(R_start) | Quaternion orientation object from world frame to frame_a at initial time |

phi_start | Angle[3] | if sequence_start[1] == sequence_angleStates[1] and sequence_start[2] == sequence_angleStates[2] and sequence_start[3] == sequence_angleStates[3] then angles_start else Frames.axesRotationsAngles(R_start, sequence_angleStates) | Potential angle states at initial time |

USED IN EXAMPLES

USED IN COMPONENTS

Modelica.Mechanics.MultiBody.Parts.BodyShape Rigid body with mass, inertia tensor, different shapes for animation, and two frame connectors (12 potential states) | |

Modelica.Mechanics.MultiBody.Parts.BodyBox Rigid body with box shape. Mass and animation properties are computed from box data and density (12 potential states) | |

Modelica.Mechanics.MultiBody.Parts.BodyCylinder Rigid body with cylinder shape. Mass and animation properties are computed from cylinder data and density (12 potential states) | |

Modelica.Mechanics.MultiBody.Parts.RollingWheel Ideal rolling wheel on flat surface z=0 (5 positional, 3 velocity degrees of freedom) | |

Modelica.Mechanics.MultiBody.Parts.RollingWheelSet Ideal rolling wheel set consisting of two ideal rolling wheels connected together by an axis |