modelCylindrical

Cylindrical joint (2 degrees-of-freedom, 4 potential states)

Extends from Modelica.Mechanics.MultiBody.Interfaces.PartialTwoFrames (Base model for components providing two frame connectors + outer world + assert to guarantee that the component is connected).

Information

Joint where frame_b rotates around and translates along axis n which is fixed in frame_a. The two frames coincide when "phi=revolute.phi=0" and "s=prismatic.s=0". This joint has the following potential states;

  • The relative angle phi [rad] around axis n,
  • the relative distance s [m] along axis n,
  • the relative angular velocity w [rad/s] (= der(phi)) and
  • the relative velocity v [m/s] (= der(s)).

They are used as candidates for automatic selection of states from the tool. This may be enforced by setting "stateSelect=StateSelect.always" in the Advanced menu. The states are usually selected automatically. In certain situations, especially when closed kinematic loops are present, it might be slightly more efficient, when using the "StateSelect.always" setting.

In the following figure the animation of a cylindrical joint is shown. The light blue coordinate system is frame_a and the dark blue coordinate system is frame_b of the joint. The black arrow is parameter vector "n" defining the cylinder axis (here: n = {0,0,1}).

Parameters

TypeNameDefaultDescription
Booleananimationtrue= true, if animation shall be enabled (show cylinder)
Modelica.Mechanics.MultiBody.Types.Axisn{1, 0, 0}Cylinder axis resolved in frame_a (= same as in frame_b)
Animation › if animation = true
SI.DistancecylinderDiameterworld.defaultJointWidthDiameter of cylinder
Advanced
StateSelectstateSelectStateSelect.preferPriority to use joint coordinates (phi, s, w, v) as states

Connectors

TypeNameDefaultDescription
Interfaces.Frame_aframe_a (from PartialTwoFrames)Coordinate system a fixed to the component with one cut-force and cut-torque
Interfaces.Frame_bframe_b (from PartialTwoFrames)Coordinate system b fixed to the component with one cut-force and cut-torque

Components

TypeNameDefaultDescription
Types.ColorcylinderColorModelica.Mechanics.MultiBody.Types.Defaults.JointColorColor of cylinder
Types.SpecularCoefficientspecularCoefficientworld.defaultSpecularCoefficientReflection of ambient light (= 0: light is completely absorbed)
Prismaticprismatic
Revoluterevolute
SI.PositionsRelative distance between frame_a and frame_b
SI.AnglephiRelative rotation angle from frame_a to frame_b
SI.VelocityvFirst derivative of s (relative velocity)
SI.AngularVelocitywFirst derivative of angle phi (relative angular velocity)
SI.AccelerationaSecond derivative of s (relative acceleration)
SI.AngularAccelerationwdSecond derivative of angle phi (relative angular acceleration)