HyLibLight

Library of hydraulic components

Information

HyLibLite is a subset of 

     HyLib - Library of Hydraulic Components for Use with Dymola. 

The following overview refers to the complete library.


OVERVIEW
========

The hydraulic library contains the most important basic hydraulic components,
in order to model hydraulic circuits. Coupling elements exist to 
connect hydraulic components with blocks of the blocks library and elements
of the mechanics library.

The library of hydraulic components supports the following types of models:

1. Modeling of 1-dimensional rotational and translation hydraulic systems.

2. As a state variable the pressure in a lumped volume is used. The inductance
   of a moving oil column can be added with the model Inductance.

3. Each component of the main library has a lumped volume connected at each 
   port. The components can therefore be connected in any sequence.


Note, there are considerable changes with regards to the previous
versions 1.xx of the library of hydraulic components. Therefore read at 
least the rules at the end of this information text.



ELEMENTS OF THE LIBRARY
=======================

The library consists of the following elements:


Pumps & Motors
   These classes model positive displacement pumps and motors. The shafts of
   the pumps and motors can be connected directly to the rotational library.
   The control inputs of the variable displacement units can be connected
   directly to outputs of the control blocks of the blocks library.

   All components have lumped volumes at the inlet and outlet ports.
   They also include the inertia of the rotating parts.

   Tank			Tank with preload pressure and conductance of tank pipe
   FlowSource           Flow source with internal leakage
   FlowSourceExtCommand Flow source with internal leakage 
			  and external command signal
   ConPump 		Constant displacement Pump with leakage
   VarPump 		Variable displacement Pump with leakage
   ConMot 		Constant displacement Motor with leakage
   VarMot 		Variable displacement Motor with leakage
   Rotor		Inertial of a rotating mass	
   Diesel		Diesel engine with speed controller
   Asynchron		Asynchron machine
   Basic		This sublibrary describes ideal pumps and motors,e. g. 
			without lumped volumes at the ports and without leakage.  

   			IdFLowSource		(IFS) Flow source, no input torque required
   			IdFLowSourceExtCommand	(IFE) Flow source, externally commanded flow rate.
   			IdConPump 		(IcP) Ideal constant displacement pump
			IdVarPump 		(IvP) Ideal Variable displacement Pump without leakage
 			IdConMot 		(IcM) Ideal Constant displacement Motor without leakage
 		  	IdVarMot 		(IVM) Ideal Variable displacement Motor without leakage
   			TankNoRes		(TnR) Tank with preload pressure

Cylinders	
   These classes model hydraulic cylinders.    
   All components have lumped volumes at the inlet and outlet 
   ports and a lumped mass for the piston.

   Cylinder1		single acting cylinder
   Cylinder2 		double acting cylinder
   ChamberA 		oil filled chamber with piston
   ChamberB 		oil filled chamber with piston



Valves
   These classes model hydraulic valves. 
   All valves have lumped volumes at the inlet and outlet ports   

   CheckValve 		check valve
   CheckValveTwo 	check valve, different characteristic
   ReliefValve 		relief valve
   SerFlowCont 		serial flow control valve
   ReducingValve 	reducing valve
   ShuttleValve 	shuttle valve
   TwoWayValve 		2 way valve
   ServoValve 		4 port servo valve
   PropValve 		4 port proportional valve
   Basic		This sublibrary describes valves without lumped volumes at the ports.

   			CheckValveNoStates 	(ChknS) check valve
   			CheckValveTwoNoStates 	(Ch2nS) check valve, different
   			ShuttleValveNoStates 	(ShunS) shuttle valve
   			ReliefValveNoStates 	(RelnS) relief valve
   			ReducingValveNoStates 	(RednS) reducing valve
   			TwoWayValveNoStates 	(TWVnS) 2 way valve   			SerFlowContNoStates 	(SFCnS) serial flow control valve
   			ServoValveNoStates 	(SeVnS) 4 port servo valve
   			PropValveNoStates 	(PrVnS) 4 port proporitional valve
			SolenoidL		solenoid with PWM
			SolenoidR		solenoid with PWM
	   		SpoolValve 		spool valve

Restrictions
   These classes model restrictions.
   All components have lumped volumes at the inlet and outlet ports.

   LamRes		Laminar resistance
   Orifice		Orifice without cavitation (standard model)
   OrificePoly		Orifice without cavitation, polynomial approach
   SimOri 		Simple Orifice model (text book model)
   OriCav 		Orifice with cavitation
   MeteringOri 		metering orifice (same approach as Orifice)
   Basic		This sublibrary describes ideal resistances, e. g. 
			without	lumped volumes at the ports.
			LamResNoStates		(LamnS) Laminar resistance without state variables
   			OrificeNoStates		(OrinS) Orifice without cavitation without state variables
			OrificePolyNoStates	(OrPnS) Orifice without cavitation, polynomial approach without state variables
   			OriCavNoStates 		(OrCnS) Orifice with cavitation without state variables
   			SimOriNoStates 		(SOrnS) Simple Orifice model (text book model) without state variables
			OrificeNNoStates 	(OrNnS) orifice model, q given dp computed
   			MeteringOriNoStates 	(MOrnS) metering orifice without state variables
			TwoOrifices             two orifices in series, one fixed, one variable
Sensors 
   These classes model measurement devices. They are used for control loops 
   that can be modelled with the blocks library  

   QMeas 		sensor for flow measuring
   PMeas 		sensor for pressure measuring

Lines
   These classes model long lines and the inertia of a moving oil column.
   
   LongLine   		Dynamic model of a long line with compressibility, 
			inductance and frequency dependent viscosity.
   RigidLine  		Losses of a rigid line as a function of Reynolds number
   Inductance 		Theoretical inductance of an oil column
   IndHole    		Inductance of a small hole

Volumes 
   These classes model the stiffness of hydraulic volumes and accumulators.

   OilVolume		Lumped volume with pressure dependent compressibilty 
			  (bulk modulus)
   VolumeConst 		lumped volume with constant bulk modulus
   VolumeTemp 		lumped volume with bulk modulus as a function
			      of pressure and temperature
   Accu1 		accumulator (simple model)
   Accu2	 	accumulator (more refined model)
   Basic		This sublibrary describes ideal accumulators without
  			lumped volumes at the ports.
   			


CONNECTOR VARIABLES
===================

Every library element has one, two or more hydraulic connectors, 
where the element can be connected to other library elements. 
The following connectors are usually provided:


 Connector Port_A  ( positive connector, oil entering the component):
 ---------------------------------------------------------------
    Across variable:
      port_A.p: Pressure in [Pa] with respect to atmospheric pressure  
	   (p stands for pressure).
 
    Through variables:
      port_A.q: Flow rate, positive if oil if entering the component at port A, in [m^3/s]

 Connector Port_B  ( negative connector, oil leaving the component):
 -------------------------------------------------------------
    Across variable:
      port_B.p: Pressure in [Pa] with respect to  atmospheric pressure
           (p stands for pressure).
 
    Through variables:
      port_B.q: Flow rate, negative if oil if leaving the component at port B, in [m^3/s]



CONNECTION RULES FOR ELEMENTS
=============================

All elements of the main hydraulic library can be connected together in an
almost arbitrary way. As almost every component of the main library has a 
lumped volume at each port a model can be build by just connecting the 
appropriate library components. The user doesn't have to add lumped volumes 
at each node to model the pressure dynamics. Dymola will reduce the index 
of the resulting DAE and solve it.

Experienced users can use the additional Basic libraries that can be found 
in the main library. These components haven't included lumped volumes at 
the ports and therefore the user has to add the required volumes or can 
use numerical solution of algebraic equations. 


Sign Convention
===============

The following sign convention is used in this library:

If the pressure at port A is greater than the pressure at port B the computed
pressure differential dp is positive and the flow rate at port_A is positive 
too. This is the same sign convention as in the mechanics libraries, where a
positive difference between across variable at flange A and across variable
at flange B gives a positive through variable, e. g. flange_a.tau greater
flange_b.tau gives a positive acceleration.



This library has been extensively tested with Dymola 4.1 beta (2000 - 05 - 19) 
and the Modelica Standard Library 1.3.2beta (2000 - 05 -16) under Windows NT 
and Windows 98.
 
This library doesn't require the following parts of the Modelica standard library:

	Electrical

The reader is cautioned that models contained in this library may not have
been exercised for all cases of interest. While every effort has been made, 
within the time available, to ensure that the models are free of 
computational and logic errors, they cannot be considered completely 
validated. Any application of these models without additional validation 
is at the risk of the user.

References

Version 1.0        (1997 - 7 - 25) Library released 
        2.0 beta 1 (1999 - 6 - 30) Adapted to Modelica and Dymola 4.0.
                                   Using lumped volumes at each port as default.
                                   Addition of OrificePoly, Line.
        2.0 beta 2 (1999 - 8 - 30) Library restructured, using packages.
        2.0 beta 3 (1999 - 10 - 5) Connectors changed
        2.0 beta 4 (2000 - 1 - 7) 
	2.0        (2000 - 2 - 23) Tests completed, library released.
	2.0 a      (2000 - 6 - 2)  Small bug fixes.