FreeMotionScalarInit

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

Diagram

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 = 45^o), angle_2(start = 45^o), angle_3(start = 45^o)).

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.

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

Inputs (2)

arrowColor	Default Value: Modelica.Mechanics.MultiBody.Types.Defaults.SensorColor Type: Color Description: Color of arrow
specularCoefficient	Default Value: world.defaultSpecularCoefficient Type: SpecularCoefficient Description: Reflection of ambient light (= 0: light is completely absorbed)

arrowColor

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

Type: Color

Description: Color of arrow

specularCoefficient

Default Value: world.defaultSpecularCoefficient

Type: SpecularCoefficient

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

Connectors (26)

	frame_a	Type: Frame_a Description: Coordinate system a fixed to the component with one cut-force and cut-torque
	frame_b	Type: Frame_b Description: Coordinate system b 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]

Components (12)

	world	Type: World
	initPosition	Type: InitPosition
	initAngle	Type: InitAngle
	initAngularVelocity	Type: InitAngularVelocity
	derv	Type: Der[3]
	dera	Type: Der[3]
	derd	Type: Der[3]
	derdd	Type: Der[3]
	derz	Type: Der[3]
	zeroForceAndTorque1	Type: ZeroForceAndTorque
	zeroForceAndTorque2	Type: ZeroForceAndTorque
	arrow	Type: SignalArrow

Used in Examples (5)

	DoublePendulumInitTip Modelica.Mechanics.MultiBody.Examples.Elementary Demonstrate how to initialize a double pendulum so that its tip starts at a predefined position
	PrismaticConstraint Modelica.Mechanics.MultiBody.Examples.Constraints Body attached by one spring and two prismatic joints or constrained to environment
	RevoluteConstraint Modelica.Mechanics.MultiBody.Examples.Constraints Body attached by one spring and revolute joint or constrained to environment
	SphericalConstraint Modelica.Mechanics.MultiBody.Examples.Constraints Body attached by one spring and spherical joint or constrained to environment
	UniversalConstraint Modelica.Mechanics.MultiBody.Examples.Constraints Body attached by one spring and universal joint or constrained to environment