cylinderdouble

Navigation:  Library > Iconic Diagrams > Hydraulics > Cylinders >

cylinderdouble

Previous pageReturn to chapter overviewNext page

Library

Iconic Diagrams\Hydraulics\Cylinders

Use

Domains: Continuous. Size: 1-D. Kind: Iconic Diagrams (Hydraulics/Translational).

Description

Cylinder1

This is the extended model of a double acting cylinder with mass, friction and end stops.

CylinderDouble

The volume of the chambers is given by:

 

Va = Vdead + Aa*(x + x_initial)

Vb = Vdead + Ab*(stroke - x - x_initial)

 

with Aa the piston area and Ab the effective area at the rod side. x is the piston position and Vdead the initial volume when piston position is zero. The piston areas Aa and Ab are related to the piston diameter dp and rod diameter dr by:

 

Aa = pi * dp^2 / 4

Ab = pi * dp^2 / 4 - pi * dr^2 / 4

PistonDiameter

The travel of the piston is restricted. At the cylinder heads two collision models prevent the piston from traveling any further. The friction between the piston and the cylinder walls is modeled by static and viscous friction.

Interface

Ports

Description

pa, pb

p_barrel, p_rod

hydraulic ports

translation ports

Causality

 

preferred pressure out pa

preferred force out pm

 

Parameters

 

Vdead

B

stroke

x_initial

dp

dr

m_barrel

m_rod

kc

dc

Fc

dv

slope

rest volume of oil in cylinder chamber when closed, [m3]

effective bulk modulus [Pa]

stroke length [m]

starting position of piston [m]

piston diameter [m]

rod diameter [m]

barrel mas [kg]

rod and piston mass [kg]

stiffness during collision with cylinder heads [N/m]

damping during collision with cylinder heads [N.s/m]

static friction [N]

viscous friction coefficient [N.s/m]

steepness of the static friction curve []

Note

When a the cylinder piston collides with the cylinder heads, simulation may get very slow or even become unstable. In these cases you are advised to use the BDF-method with default settings. Try to change the absolute integration error until a stable simulation is obtained!