WOLFRAM SYSTEMMODELER

FreeMotionScalarInit

Free motion joint with scalar initialization and state selection (6 degrees-of-freedom, 12 potential states)

Diagram

Wolfram Language

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SystemModel["Modelica.Mechanics.MultiBody.Joints.FreeMotionScalarInit"]
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Information

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

Joint which does not constrain the motion between frame_a and frame_b. Such a joint is meaningful if the relative distance and orientation between frame_a and frame_b, and their derivatives, shall be used as states or shall be used for non-standard initialization. This joint allows to initialize every scalar element of the relative quantities, as well as to define StateSelect attributes for every scalar element separately.

In the following figure the animation of a FreeMotionScalarInit joint is shown. The light blue coordinate system is frame_a and the dark blue coordinate system is frame_b of the joint. (here: r_rel_a_1(start = 0.5), r_rel_a_2(start = 0), r_rel_a_3(start = 0.5), angle_1(start = 45o), angle_2(start = 45o), angle_3(start = 45o)).

A example to use this joint for the initialization of a planar double pendulum by providing its tip position, is shown in Examples.Elementary.DoublePendulumInitTip.

Connectors (26)

frame_a

Type: Frame_a

Description: Coordinate system fixed to the component with one cut-force and cut-torque

frame_b

Type: Frame_b

Description: Coordinate system fixed to the component with one cut-force and cut-torque

r_rel_a_1

Type: RealOutput

Description: Relative distance r_rel_a[1]

r_rel_a_2

Type: RealOutput

Description: Relative distance r_rel_a[2]

r_rel_a_3

Type: RealOutput

Description: Relative distance r_rel_a[3]

v_rel_a_1

Type: RealOutput

Description: Relative velocity v_rel_a[1]

v_rel_a_2

Type: RealOutput

Description: Relative velocity v_rel_a[2]

v_rel_a_3

Type: RealOutput

Description: Relative velocity v_rel_a[3]

a_rel_a_1

Type: RealOutput

Description: Relative acceleration a_rel_a[1]

a_rel_a_2

Type: RealOutput

Description: Relative acceleration a_rel_a[2]

a_rel_a_3

Type: RealOutput

Description: Relative acceleration a_rel_a[3]

angle_1

Type: RealOutput

Description: First rotation angle or dummy

angle_2

Type: RealOutput

Description: Second rotation angle or dummy

angle_3

Type: RealOutput

Description: Third rotation angle or dummy

angle_d_1

Type: RealOutput

Description: = der(angle_1)

angle_d_2

Type: RealOutput

Description: = der(angle_2)

angle_d_3

Type: RealOutput

Description: = der(angle_3)

angle_dd_1

Type: RealOutput

Description: = der(angle_d_1)

angle_dd_2

Type: RealOutput

Description: = der(angle_d_2)

angle_dd_3

Type: RealOutput

Description: = der(angle_d_3)

w_rel_b_1

Type: RealOutput

Description: Relative angular velocity w_rel_b[1]

w_rel_b_2

Type: RealOutput

Description: Relative angular velocity w_rel_b[2]

w_rel_b_3

Type: RealOutput

Description: Relative angular velocity w_rel_b[3]

z_rel_b_1

Type: RealOutput

Description: Relative angular acceleration z_rel_b[1]

z_rel_b_2

Type: RealOutput

Description: Relative angular acceleration z_rel_b[2]

z_rel_b_3

Type: RealOutput

Description: Relative angular acceleration z_rel_b[3]

Parameters (26)

animation

Value: true

Type: Boolean

Description: = true, if animation shall be enabled (show arrow from frame_a to frame_b)

use_r

Value: false

Type: Boolean

Description: = true, if r_rel_a shall be used

r_rel_a_1_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of r_rel_a[1]

r_rel_a_2_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of r_rel_a[2]

r_rel_a_3_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of r_rel_a[3]

use_v

Value: false

Type: Boolean

Description: = true, if v_rel_a shall be used

v_rel_a_1_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of v_rel_a[1]

v_rel_a_2_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of v_rel_a[2]

v_rel_a_3_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of v_rel_a[3]

use_a

Value: false

Type: Boolean

Description: = true, if a_rel_a shall be used

use_angle

Value: false

Type: Boolean

Description: = true, if angle shall be used

sequence_start

Value: {1, 2, 3}

Type: RotationSequence

Description: Sequence of angle rotations

angle_1_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of angle_1

angle_2_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of angle_2

angle_3_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of angle_3

use_angle_d

Value: false

Type: Boolean

Description: = true, if angle_d shall be used

angle_d_1_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of angle_d_1

angle_d_2_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of angle_d_2

angle_d_3_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of angle_d_3

use_angle_dd

Value: false

Type: Boolean

Description: = true, if angle_dd shall be used

use_w

Value: false

Type: Boolean

Description: = true, if w_rel_b shall be used

w_rel_b_1_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of w_rel_b[1]

w_rel_b_2_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of w_rel_b[2]

w_rel_b_3_stateSelect

Value: StateSelect.never

Type: StateSelect

Description: StateSelect of w_rel_b[3]

use_z

Value: false

Type: Boolean

Description: = true, if z_rel_b shall be used

arrowDiameter

Value: world.defaultArrowDiameter

Type: Length (m)

Description: Diameter of arrow from frame_a to frame_b

Components (12)

world

Type: World

Description:

initPosition

Type: InitPosition

Description:

initAngle

Type: InitAngle

Description:

initAngularVelocity

Type: InitAngularVelocity

Description:

derv

Type: Der[3]

Description:

dera

Type: Der[3]

Description:

derd

Type: Der[3]

Description:

derdd

Type: Der[3]

Description:

derz

Type: Der[3]

Description:

zeroForceAndTorque1

Type: ZeroForceAndTorque

Description:

zeroForceAndTorque2

Type: ZeroForceAndTorque

Description:

arrow

Type: SignalArrow

Description:

Used in Examples (5)

DoublePendulumInitTip

Demonstrate how to initialize a double pendulum so that its tip starts at a predefined position

PrismaticConstraint

Body attached by one spring and two prismatic joints or constrained to environment

RevoluteConstraint

Body attached by one spring and revolute joint or constrained to environment

SphericalConstraint

Body attached by one spring and spherical joint or constrained to environment

UniversalConstraint

Body attached by one spring and universal joint or constrained to environment