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
APPENDIX
Release Notes
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.
Copyright (C) 2000, Peter Beater.
The HyLibLight package is free software; it can be redistributed and/or modified under the terms of the Modelica license and the accompanying disclaimer.