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MapleSim Hydraulics Library from Modelon

Differential Cylinder  Model of a differential cylinder

This model is a double acting cylinder with a rod on one side and damping at the ends modeled with springs and dampers. This model has two active chambers on either side of the piston and internal leakage but only external leakage from chamberB. External leakage can be turned off by clearing the hasExternalLeakage setting (found under the Properties tab ( ) in the Parameters   Leakage section.

Cylinder Geometry This is a simplified overview of the geometric parameters defining the cylinder geometry:

Mechanical Friction This model includes Stribeck Friction (see the following figure).

 

Variables

Connections

Parameters

Variables

Name

Value

Units

Description

Modelica ID

internalLeakage

 

 

Internal Leakage

internalLeakage

chamberA

 

 

A-side chamber

chamberA

chamberB

 

 

B-side chamber

chamberB

PistonInCylinder

 

 

Single rod piston in a cylinder

PistonInCylinder

rodA

 

 

From flange_a to piston head

rodA

piston

 

 

Piston length

piston

cylinderFriction

 

 

Pressure dependent friction between piston and cylinder

cylinderFriction

friction

 

 

Friction between piston and cylinder

friction

environment

 

 

 

environment

external leakage

 

 

External leakage

externalLeakage

pAsummary

pA

Pa

Pressure at port A

summary_pA

pBsummary

pB

Pa

Pressure at port B

summary_pB

Pmechsummary

[1]

W

Mechanical translational power

summary_MP

fbsummary

fb

N

Force acting on flange b

summary_fb

fbearingsummary

mount.f

N

Force acting on bearing

summary_fbearing

qchamAsummary

chamberA.qcham

m3s

Flow rate flowing into Chamber A

summary_qChamA

qchamBsummary

chamberB.qcham

m3s

Flow rate flowing into Chamber B

summary_qChamB

strokesummary

[2]

m

Cylinder stroke

summary_stroke

vsummary

[3]

ms

Cylinder velocity

summary_v

PhydAsummary

chamberA.summary_HP

W

Hydraulic Power in chamber A

summary_HP_A

PhydBsummary

chamberB.summary_HP

W

Hydraulic Power in chamber A

summary_HP_B

[1] s.bfb+s.mountfmount

[2] PistonInCylinder.motion.s_rel

[3] PistonInCylinder.motion.v_rel

Connections

Name

Description

Modelica ID

portA

Port A, where oil flows into the component (positive q, port_A.p > chamberA.p means positive dp)

port_A

portB

Port B, where oil flows into the component (positive q, port_B.p > chamberB.p means positive dp)

port_B

flangeb

Piston rod mounting point b

flange_b

mount

Cylinder housing mounting point

mount

Parameters

General Parameters

Name

Default

Units

Description

Modelica ID

rodb

12

m

Length of rod, side b

RodLength_b

housing

2

m

Length of housing

HousingLength

piston

0.05

m

Length of piston

PistonLength

mpiston

100

kg

Effective mass of piston and rigidly coupled masses

PistonMass

cA

108

Nm

Stiffness of stop at stroke end A

c_A

dA

106

Nsm

Damping of stop at stroke end A

d_A

cB

108

Nm

Stiffness of stop at stroke end B

c_B

dB

106

Nsm

Damping of stop at stroke end B

d_B

ApistonA

0.001

m2

Effective area of left side of piston

piston_areaA

ApistonB

0.001

m2

Effective area of right side of piston

piston_areaB

VdeadA

0.001

m3

Dead volume of chamber if piston is at left end of housing (side A: stroke = 0)

dead_volumeA

VdeadB

0.001

m3

Dead volume of chamber if piston is at right end of housing (side B: stroke = max)

dead_volumeB

kp

0

 

Pressure damping coefficient

kp

ΔTsystem

0

K

Temperature offset from system temperature

dT_system

reverse

false

 

Reverse the positive flow in the component

reverse

Friction Parameters

Name

Default

Units

Description

Modelica ID

fbreakaway

100

N

 

breakaway_friction

fmixed

10

N

 

mixed_friction

vfmixed

110

ms

 

mixed_friction_velocity

dviscous

2.5·103

Nsm

 

viscous_damping

tabular

false

 

If true, use tabular models, else an analytic one

Tabular

fpos

0.,1.

 

[v, f] Positive sliding friction characteristic (v>=0)

f_pos

Initialization Parameters

Name

Default

Units

Description

Modelica ID

InitialStrokeA

[1]

m

Initial stroke of cylinder chamber A, default is middle position

InitialStroke_A

[1] 12housing12piston

Leakage Parameters

Name

Default

Units

Description

Modelica ID

has external leakage

true

 

If true, external leakage at rod seal is included

hasExternalLeakage

Gext

4.2·10-13

m3sPa

Hydraulic conductance for external leakage

G_ext

Gleakint

0

m3sPa

Hydraulic conductance G=∂q∂p

G_intLeak

See Also

Cylinders

MapleSim Hydraulics Library from Modelon Overview

 


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