Prismatic

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

    Prismatic

Library

Mechanics/MultiBody/Joints

Description

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

Prismatic_0

NameLabelDescriptionData TypeValid Values

mo_useAxisFlange

useAxisFlange

= true, if axis flange is enabled

Number

0
1

mo_animation

animation

= true, if animation shall be enabled

Scalar

true
false

mo_n

n

Axis of translation resolved in frame_a (= same as in frame_b)

Vector of size 3

mo_s_offset

s_offset

Relative distance offset (distance between frame_a and frame_b = s_offset + s)

Scalar

mo_e

e

Unit vector in direction of prismatic axis n

Vector of size 3

Prismatic_1

NameLabelDescriptionData TypeValid Values

mo_boxWidthDirection

boxWidthDirection

Vector in width direction of box, resolved in frame_a

Vector of size 3

mo_boxWidth

boxWidth

Width of prismatic joint box

Scalar

mo_boxHeight

boxHeight

Height of prismatic joint box

Scalar

mo_boxColor

boxColor

Color of prismatic joint box

Vector of size 3

mo_specularCoefficient

specularCoefficient

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

Scalar

Prismatic_2

NameLabelDescriptionData TypeValid Values

mo_stateSelect

stateSelect

Priority to use distance s and v=der(s) as states

Structure

mo_stateSelect/choice1

StateSelect.never

Number

0
1

mo_stateSelect/choice2

StateSelect.avoid

Number

0
1

mo_stateSelect/choice3

StateSelect.default

Number

0
1

mo_stateSelect/choice4

StateSelect.prefer

Number

0
1

mo_stateSelect/choice5

StateSelect.always

Number

0
1

Prismatic_3

NameLabelDescriptionData TypeValid Values

mo_s

s

s

Structure

mo_s/fixed

fixed

Cell of scalars

true
false

mo_s/start

start

Cell of scalars

mo_v

v

v

Structure

mo_v/fixed

fixed

Cell of scalars

true
false

mo_v/start

start

Cell of scalars

mo_a

a

a

Structure

mo_a/fixed

fixed

Cell of scalars

true
false

mo_a/start

start

Cell of scalars

mo_f

f

f

Structure

mo_f/fixed

fixed

Cell of scalars

true
false

mo_f/start

start

Cell of scalars

Ports

NameTypeDescriptionIO TypeNumber

frame_a

implicit

Coordinate system fixed to the joint with one cut-force and cut-torque

input

1

frame_b

implicit

Coordinate system fixed to the joint with one cut-force and cut-torque

output

1

Port 3

implicit

1-dim. translational flange that drives the joint

input

mo_useAxisFlange

Port 4

implicit

1-dim. translational flange of the drive support (assumed to be fixed in the world frame, NOT in the joint)

output

mo_useAxisFlange