Variable Displacement Motor - MapleSim Help

Variable Displacement Motor

Variable displacement motor/pump with mechanical and volumetric efficiency maps

 Description The Variable Displacement Motor and Variable Displacement Pump are identical devices that can be used as either a motor or pump.

Data Source Option

The mechanical and volumetric efficiency of the motor can be set to a constant or computed based on its dependencies. When the variation is constant the ${\mathrm{\eta }}_{\mathrm{mech}}$ and ${\mathrm{\eta }}_{\mathrm{vol}}$ given by the user are used in calculations. When specifying the variation as a function of pressure difference and displacement or as a function of speed and pressure difference, any one of the below mentioned Data source options can be selected:

 – Data Source: This parameter allows users to specify the nature of the source file table. The available options are file, attachment, and inline.
 • file: Use this option to specify a source file (an Excel or a CSV file) located on the hard drive. Use the ${\mathrm{\eta }}_{\mathrm{mech}}$ and ${\mathrm{\eta }}_{\mathrm{vol}}$ parameter drop-down menus to browse and/or select a data file. The data file will not be attached to the MapleSim model.
 • attachment: Use this option to specify a data file (an Excel or a CSV file) that is attached to the MapleSim model. To be used as an attachment, data files must be attached to the MapleSim model and be categorized under Data Sets. The attached files in a MapleSim model can be viewed in the Attachments pane under the Data Sets section. For more information, see Attaching a File to a Model. If the required file is not already attached to the MapleSim model, use the ${\mathrm{\eta }}_{\mathrm{mech}}$ and ${\mathrm{\eta }}_{\mathrm{vol}}$ parameter drop-down menus to attach a new file.

Note:

 • If the file option is used, subsequent changes to the source file will be reflected in MapleSim simulations
 • If the attachment option is used, subsequent changes to the source file will not affect the version attached to the MapleSim model. To ensure updates to the source files are reflected in the simulation, the file must be reattached.
 • The Data Generation App can be used to generate table data from mathematical functions using Maple code. For more information about MapleSim apps, see Opening MapleSim Apps and Templates.
 • inline: Use this option to directly specify the ${\mathrm{\eta }}_{\mathrm{mech}}$ and ${\mathrm{\eta }}_{\mathrm{vol}}$ values as a function of the quantities listed in the Variation drop-down menu. The data is entered in the form of a table.

Note: To change the dimensions of the table, right-click (Control-click for Mac®) the parameter field and select Edit Matrix Dimensions. In the Matrix Dimensions dialog, enter values for the number or rows and columns and then click OK.

The data specified by the options mentioned above must conform to the following formatting:

 • In an $m×n$ matrix A, the elements 2 through m of the first column contain the values of the first quantity listed in the Variation drop-down menu.
 – In an $m×n$ matrix A, the elements 2 through n of the first row contain the values of the second quantity listed in the Variation drop-down menu.
 – The values of the dependent quantity (${\mathrm{\eta }}_{\mathrm{mech}}$, ${\mathrm{\eta }}_{\mathrm{vol}}$) are specified in the remaining elements of the matrix. The entry ${A}_{\mathrm{ij}}$ corresponds to the value of ${\mathrm{\eta }}_{\mathrm{mech}}$, ${\mathrm{\eta }}_{\mathrm{vol}}$ for the i-th value of the first quantity listed in the Variation drop-down menu and the j-th value of the second quantity listed in the Variation drop-down menu.
 – Skip rows: This option allows users to specify the number of top rows to be ignored during the calculations. This option can be useful when the Excel file contains header information.
 – Smooth: The smooth option allows to specify how the data table is interpolated.
 – Pressure difference unit: This option allows users to select the unit of pressure used in the supplied data.
 – Disp unit: This option allows users to select the unit of displacement used in the supplied data.

Connections

 Name Description Modelica ID $\mathrm{portA}$ Upstream hydraulic port portA $\mathrm{portB}$ Downstream hydraulic port portB $\mathrm{disp}$ Optional real input; commanded displacement per revolution disp ${\mathrm{flange}}_{b}$ Right flange of compliant 1-dim. rotational component flange_b

Parameters

Data Units Parameters

 Name Default Units Description Modelica ID Pressure difference unit $\mathrm{kPa}$ Unit for pressure data pressUnit Angular velocity unit $\mathrm{rpm}$ Unit for angular velocity data speedUnit Disp. unit ${\mathrm{cm}}^{3}$ Unit for displacement data dispUnit

Displacement Parameters

 Name Default Units Description Modelica ID Use variable displacement $\mathrm{false}$ True means enable disp input useVariableDisplacement $\mathrm{D}$ $1·{10}^{-4}$ ${m}^{3}$ Constant displacement per revolution D ${\mathrm{D}}_{\mathrm{max}}$ $1·{10}^{-4}$ ${m}^{3}$ Maximum displacement per revolution Dmax Disp. input unit ${\mathrm{cm}}^{3}$ Unit for displacement data dispInUnit

Mechanical Efficiency Parameters

 Name Default Units Description Modelica ID Variation $\mathrm{constant}$ Efficiency parameterization paramType1 ${\mathrm{\eta }}_{\mathrm{mech}}$ $1$ Constant mechanical efficiency. Use values between 0 and 1. MechEff Data source inline Data source datasourcemode1 ${\mathrm{\eta }}_{\mathrm{mech}}$ [0,0.5,1; 0.5,0.9,0.9; 1,0.9,0.9] Data set table1 Smooth linear segments Smoothness of table interpolation smoothness1

Motor/Pump Switching Parameters

 Name Default Units Description Modelica ID Pressure difference threshold $1·{10}^{4}$ $\mathrm{Pa}$ Motor/Pump switching threshold pressThreshold Angular velocity threshold $\frac{\mathrm{\pi }}{3}$ $\frac{\mathrm{rad}}{s}$ Motor/Pump switching threshold speedThreshold Disp. threshold $1·{10}^{-7}$ ${m}^{3}$ Motor/Pump switching threshold dispThreshold $\mathrm{TPM}$ $0.001$ $s$ Motor/Pump switching time constant TPM

Volumetric Efficiency Parameters

 Name Default Units Description Modelica ID Variation $1$ Efficiency parameterization paramType2 ${\mathrm{\eta }}_{\mathrm{vol}}$ $1$ Constant mechanical efficiency. Use values between 0 and 1. VolEff Data source inline Data source datasourcemode2 ${\mathrm{\eta }}_{\mathrm{vol}}$ [0,0.5,1; 0.5,0.9,0.9; 1,0.9,0.9] Data set table2 ${\mathrm{\eta }}_{\mathrm{vol}}$ Attached Data Set data2 Smooth linear segments Smoothness of table interpolation smoothness2