Prismatic

Prismatic joint (1 translational degree-of-freedom, 2 potential states, optional axis flange)

Diagram

Information

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

Joint where frame_b is translated along axis n which is fixed in frame_a. The two frames coincide when the relative distance "s = 0".

Optionally, two additional 1-dimensional mechanical flanges (flange "axis" represents the driving flange and flange "support" represents the bearing) can be enabled via parameter useAxisFlange. The enabled axis flange can be driven with elements of the Modelica.Mechanics.Translational library.

In the "Advanced" menu it can be defined via parameter stateSelect that the relative distance "s" and its derivative shall be definitely used as states by setting stateSelect=StateSelect.always. Default is StateSelect.prefer to use the relative distance and its derivative as preferred states. 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 prismatic 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 translation axis (here: n = {1,1,0}).

Parameters (8)

useAxisFlange	Value: false Type: Boolean Description: = true, if axis flange is enabled
animation	Value: true Type: Boolean Description: = true, if animation shall be enabled
n	Value: {1, 0, 0} Type: Axis Description: Axis of translation resolved in frame_a (= same as in frame_b)
boxWidthDirection	Value: {0, 1, 0} Type: Axis Description: Vector in width direction of box, resolved in frame_a
boxWidth	Value: world.defaultJointWidth Type: Distance (m) Description: Width of prismatic joint box
boxHeight	Value: boxWidth Type: Distance (m) Description: Height of prismatic joint box
stateSelect	Value: StateSelect.prefer Type: StateSelect Description: Priority to use distance s and v=der(s) as states
e	Value: Modelica.Math.Vectors.normalizeWithAssert(n) Type: Real[3] Description: Unit vector in direction of prismatic axis n

Inputs (2)

boxColor	Default Value: Modelica.Mechanics.MultiBody.Types.Defaults.JointColor Type: Color Description: Color of prismatic joint box
specularCoefficient	Default Value: world.defaultSpecularCoefficient Type: SpecularCoefficient Description: Reflection of ambient light (= 0: light is completely absorbed)

boxColor

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

Type: Color

Description: Color of prismatic joint box

specularCoefficient

Default Value: world.defaultSpecularCoefficient

Type: SpecularCoefficient

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

Connectors (4)

	frame_a	Type: Frame_a Description: Coordinate system fixed to the joint with one cut-force and cut-torque
	frame_b	Type: Frame_b Description: Coordinate system fixed to the joint with one cut-force and cut-torque
	axis	Type: Flange_a Description: 1-dim. translational flange that drives the joint
	support	Type: Flange_b Description: 1-dim. translational flange of the drive support (assumed to be fixed in the world frame, NOT in the joint)

Components (5)

	world	Type: World
	box	Type: Shape
	fixed	Type: Fixed
	internalAxis	Type: InternalSupport
	constantForce	Type: ConstantForce

Used in Examples (9)

	PendulumWithSpringDamper Modelica.Mechanics.MultiBody.Examples.Elementary Simple spring/damper/mass system
	SpringDamperSystem Modelica.Mechanics.MultiBody.Examples.Elementary Simple spring/damper/mass system
	SpringMassSystem Modelica.Mechanics.MultiBody.Examples.Elementary Mass attached with a spring to the world frame
	Surfaces Modelica.Mechanics.MultiBody.Examples.Elementary Demonstrate the visualization of a sine surface, as well as a torus and a wheel constructed from a surface
	Engine1a Modelica.Mechanics.MultiBody.Examples.Loops Model of one cylinder engine
	Engine1b Modelica.Mechanics.MultiBody.Examples.Loops Model of one cylinder engine with gas force and preparation for assembly joint JointRRP
	Fourbar1 Modelica.Mechanics.MultiBody.Examples.Loops One kinematic loop with four bars (with only revolute joints; 5 non-linear equations)
	Fourbar2 Modelica.Mechanics.MultiBody.Examples.Loops One kinematic loop with four bars (with UniversalSpherical joint; 1 non-linear equation)
	PrismaticConstraint Modelica.Mechanics.MultiBody.Examples.Constraints Body attached by one spring and two prismatic joints or constrained to environment

Used in Components (4)

	Cylinder Modelica.Mechanics.MultiBody.Examples.Loops.Utilities Cylinder with rod and crank of a combustion engine
	Cylindrical Modelica.Mechanics.MultiBody.Joints Cylindrical joint (2 degrees-of-freedom, 4 potential states)
	Planar Modelica.Mechanics.MultiBody.Joints Planar joint (3 degrees-of-freedom, 6 potential states)
	RollingWheelSet Modelica.Mechanics.MultiBody.Joints Joint (no mass, no inertia) that describes an ideal rolling wheel set (two ideal rolling wheels connected together by an axis)