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

Spherical

Spherical joint (3 constraints and no potential states, or 3 degrees-of-freedom and 3 states)

Information
CONNECTORS
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NameTypeDescription
frame_aFrame_aCoordinate system fixed to the component with one cut-force and cut-torque
frame_bFrame_bCoordinate system fixed to the component with one cut-force and cut-torque
PARAMETERS
NameTypeDefault ValueDescription
animationBooleantrue= true, if animation shall be enabled (show sphere)
sphereDiameterDistanceworld.defaultJointLengthDiameter of sphere representing the spherical joint
angles_fixedBooleanfalse= true, if angles_start are used as initial values, else as guess values
angles_startAngle[3]{0,0,0}Initial values of angles to rotate frame_a around 'sequence_start' axes into frame_b
sequence_startRotationSequence{1,2,3}Sequence of rotations to rotate frame_a into frame_b at initial time
w_rel_a_fixedBooleanfalse= true, if w_rel_a_start are used as initial values, else as guess values
w_rel_a_startAngularVelocity[3]{0,0,0}Initial values of angular velocity of frame_b with respect to frame_a, resolved in frame_a
z_rel_a_fixedBooleanfalse= true, if z_rel_a_start are used as initial values, else as guess values
z_rel_a_startAngularAcceleration[3]{0,0,0}Initial values of angular acceleration z_rel_a = der(w_rel_a)
enforceStatesBooleanfalse = true, if relative variables of spherical joint shall be used as states (StateSelect.always)
useQuaternionsBooleantrue = true, if quaternions shall be used as states otherwise use 3 angles as states (provided enforceStates=true)
sequence_angleStatesRotationSequence{1,2,3} Sequence of rotations to rotate frame_a into frame_b around the 3 angles used as states
R_rel_startOrientationFrames.axesRotations(sequence_start, angles_start, zeros(3))Orientation object from frame_a to frame_b at initial time
Q_startOrientationModelica.Mechanics.MultiBody.Frames.to_Q(R_rel_start)Quaternion orientation object from frame_a to frame_b at initial time
phi_startAngle[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_rel_start, sequence_angleStates)Potential angle states at initial time
USED IN EXAMPLES
Modelica.Mechanics.MultiBody.Examples.Rotational3DEffects.GyroscopicEffects
Demonstrates that a cylindrical body can be replaced by Rotor1D model