PointMass

Body used at all places of the comparison model with zero inertia tensor

Information

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

Body used at all places of the comparison model with zero inertia tensor (and mass = 1 kg and a red color).

Parameters (23)

animation

Value: true

Type: Boolean

Description: = true, if animation shall be enabled (show cylinder and sphere)

r_CM

Value: {0, 0, 0}

Type: Position[3] (m)

Description: Vector from frame_a to center of mass, resolved in frame_a

m

Value: 1

Type: Mass (kg)

Description: Mass of rigid body

I_11

Value: 0

Type: Inertia (kg·m²)

Description: Element (1,1) of inertia tensor

I_22

Value: 0

Type: Inertia (kg·m²)

Description: Element (2,2) of inertia tensor

I_33

Value: 0

Type: Inertia (kg·m²)

Description: Element (3,3) of inertia tensor

I_21

Value: 0

Type: Inertia (kg·m²)

Description: Element (2,1) of inertia tensor

I_31

Value: 0

Type: Inertia (kg·m²)

Description: Element (3,1) of inertia tensor

I_32

Value: 0

Type: Inertia (kg·m²)

Description: Element (3,2) of inertia tensor

angles_fixed

Value: false

Type: Boolean

Description: = true, if angles_start are used as initial values, else as guess values

angles_start

Value: {0, 0, 0}

Type: Angle[3] (rad)

Description: Initial values of angles to rotate world frame around 'sequence_start' axes into frame_a

sequence_start

Value: {1, 2, 3}

Type: RotationSequence

Description: Sequence of rotations to rotate world frame into frame_a at initial time

w_0_fixed

Value: false

Type: Boolean

Description: = true, if w_0_start are used as initial values, else as guess values

w_0_start

Value: {0, 0, 0}

Type: AngularVelocity[3] (rad/s)

Description: Initial or guess values of angular velocity of frame_a resolved in world frame

z_0_fixed

Value: false

Type: Boolean

Description: = true, if z_0_start are used as initial values, else as guess values

z_0_start

Value: {0, 0, 0}

Type: AngularAcceleration[3] (rad/s²)

Description: Initial values of angular acceleration z_0 = der(w_0)

sphereDiameter

Value: world.defaultBodyDiameter

Type: Diameter (m)

Description: Diameter of sphere

cylinderDiameter

Value: sphereDiameter / Types.Defaults.BodyCylinderDiameterFraction

Type: Diameter (m)

Description: Diameter of cylinder

enforceStates

Value: false

Type: Boolean

Description: = true, if absolute variables of body object shall be used as states (StateSelect.always)

useQuaternions

Value: true

Type: Boolean

Description: = true, if quaternions shall be used as potential states otherwise use 3 angles as potential states

sequence_angleStates

Value: {1, 2, 3}

Type: RotationSequence

Description: Sequence of rotations to rotate world frame into frame_a around the 3 angles used as potential states

I

Value: [I_11, I_21, I_31; I_21, I_22, I_32; I_31, I_32, I_33]

Type: Inertia[3,3] (kg·m²)

Description: Inertia tensor

R_start

Value: Modelica.Mechanics.MultiBody.Frames.axesRotations(sequence_start, angles_start, zeros(3))

Type: Orientation

Description: Orientation object from world frame to frame_a at initial time

Inputs (3)

sphereColor

Default Value: Modelica.Mechanics.MultiBody.Types.Defaults.BodyColor

Type: Color

Description: Color of sphere

cylinderColor

Default Value: sphereColor

Type: Color

Description: Color of cylinder

specularCoefficient

Default Value: world.defaultSpecularCoefficient

Type: SpecularCoefficient

Description: Reflection of ambient light (= 0: light is completely absorbed)

Connectors (1)

frame_a

Type: Frame_a

Description: Coordinate system fixed at body

Components (4)

R_start

Type: Orientation

Description: Orientation object from world frame to frame_a at initial time

world

Type: World

cylinder

Type: Shape

sphere

Type: Shape

Used in Components (1)

SystemWithStandardBodies

Modelica.Mechanics.MultiBody.Examples.Elementary.PointGravityWithPointMasses2

For comparison purposes, an equivalent model with Bodies instead of PointMasses