Tutorials Tutorial 5 - TypeDesigner

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1 Tutorials Tutorial 5 - TypeDesigner Objective The software includes a helpful tool for creating, or extending element types - the TypeDesigner. In this tutorial we guide you step by step into the work with the TypeDesigner. Based on a nonlinear spring damper we explain the handling of the TypeDesigner. You can easily repeat this on your own computer. Many actions can be performed in several ways. In this introduction only one is usually demonstrated and used. It is assumed that you are familiar with the basic functionality of. Therefore, please refer to Tutorial 1: Getting Started for a general introduction on how to select elements from the libraries, how to connect them and enter parameters, how to run a simulation and how to open result windows. Using the TypeDesigner Creating new element types Adding components TypeDesigner - What Can It Be Used For? create and edit user-defined types add certain features to the built-in types group several elements together to one new type edit the model (= model type) Working with activity groups Description of the behavior Using Modelica Documentation of types Figure 1: TypeDesigner - page 'General' (for global types) The creation process of new types is very easy using the TypeDesinger. The TypeDesigner leads you through the individual steps towards the user-defined type. Example: Let us create a new type 'Nonlinear Spring Damper' with the following attributes: local type, that means the type is available only in this model

2 Page 2 of 11 selection of the behavior (Spring, Damper, Spring-Damper); the corresponding parameters are toggled depending on the user s selection the spring-damper is linear (constant stiffness and damping) or nonlinear (stiffness curve Fs=f(x) and damping curve Fd=g(dv)) parameters are visible/invisible depending on the behavior of the spring-damper Creating a New Type Figure 2: Model Explorer - Tab Types We start and open the tab Types in the Model Explorer. By clicking with right mouse button on the model name we can select 'New model'. In the result of this the TypeDesinger opens (see Figure 1). For navigation between the different pages you can use the buttons in the bottom of the window or select a page directly on the left hand side of the window. General On this page leave the environment and the name at their default settings. Go to the next page by clicking on the button 'Next'. Connectors Because the type should have two linear mechanical connectors we add these on the page 'Connectors'. Select the desired connector type and add it by using the add button in the control. Add connector Delete connector Move connector upwards in list Move connector downwards in list Figure 3: Connectors of the new type Components To add components to the type, on the page 'Component' select the components and add them in the same way as the connectors. The function of the buttons in the control is the same as at the connectors page. Then fill in the name, comment and additional information for each of the components. These components will be shown as the parameters and variables of the new type. You can hide components that are only used for internal computations. ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

3 Page 3 of 11 The following components are needed for the nonlinear Spring-Damper: Not specified entries remain as preset. Component Variable Inputs/Parameters This is the result variable of the type - the internal force of the Spring-Damper. For the physical quantity select the item 'Force' in the Domain 'Mechanics (Linear)'. Boolean This Boolean variable is used for switching between linear and nonlinear behavior. Enumeration For adding a component Enumeration to the spring-damper you have to create a new component. With this enumeration you can select the behavior of the spring-damper. It controls the visibility of the parameters and is also used for computation. Alternatives are used for switching between the different kinds of the spring-damper. For controlling the different behavior options, they include the following alternatives: ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

4 Page 4 of 11 It is possible to set the default alternative and the visibility on the page parameters in the element type. Parameter This parameter is used for linear behavior of the spring-damper. For the physical quantity select the item 'Linear Stiffness' in the Domain 'Mechanics (Linear)'. Parameter This parameter is used for linear behavior of the spring-damper. For the physical quantity select the item 'Linear Damping Constant' in the Domain 'Mechanics (Linear)'. Curve This curve is used for nonlinear behavior of the spring-damper. It defines the spring force as a function of the displacement difference (Fs=f(x)). For the physical quantity select the item 'Displacement' in the Domain 'Mechanics (Linear)'. For the physical quantity select the item 'Force' in the Domain 'Mechanics (Linear)'. ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

5 Page 5 of 11 Curve This curve is used for nonlinear behavior of the spring-damper. It defines the damping force as a function of the velocity difference (Fd=g(dv)). For the physical quantity select the item 'Velocity' in the Domain 'Mechanics (Linear)'. For the physical quantity select the item 'Force' in the Domain 'Mechanics (Linear)'. Local Types On this page you can add local types, such as functions, enumerations or simblocks. In this example you see here the component enumeration of the new type created before. It will be shown as a local type. Figure 4: Representation of the enumeration as local type Activity Groups Activity groups are useful for toggling parameters, variables and other components. The group behavior depends on Boolean expressions and enumeration settings. Components belonging to one group are switched on or off. Components can belong to several groups. The following table shows the assignment of the parameters in the example: Behavior Parameter Spring sdb_select = 1 Damper sdb_select = 2 Spring-Damper sdb_select = 3 AsCurve k x x b x x k_curve x x b_curve x x Before the defining and using of Activity Groups you have to enable the Activity Group support. ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

6 Page 6 of 11 Activity Groups Enabling Activity Groups for the toggling of parameters. One group is defined for each parameter. Behavior For better understanding of the behavior description let us have a look to the element connection (node). Figure 5: Node description The conventions (see Figure 5) are as follows 1. Potential differences such as displacement or speed differences are calculated as ctr1 - ctr2. 2. Positive element forces are expanding forces (increase potential diff.). - A mass at connector 1 moves in negative direction for Fi>0 - A mass at connector 2 moves in positive direction for Fi>0 3. Connections balance forces, which decrease the potential (decelerating forces) Positive element forces are written as +F to ctr1 and as -F to ctr2. For the description of the behavior you can use all available parameters, variables and components of the type. These are listed in a tree-structure on the left of the page Behavior and can also be picked via drag-and-drop. Equations of any kind can be entered on the page Behavior. The processing order is determined automatically. The Syntax is:... =... ; You can use control structures such as when... then...elsewhen... end when; if... then... elseif.. else... end if; for... in... loop; ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

7 Page 7 of 11 Equations should be generally preferred for any problem description. Exceptions are problems which can be described only as algorithms e.g. iterations. Algorithms can be also entered on the page Behavior. The processing order is equivalent to the order of notation. The Syntax is:...:=... ; You can use control structures such as if... then... else elseif... end if; for... in... loop; while... loop... end while; For the spring-damper example you have to enter the following notation (see Figure 6) on the page Behavior. Figure 6: Page Behavior - Equation section If there are syntax errors in the formulated equations a message occurs and the equation must be corrected before leaving the TypeDesigner. Modelica Code ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

8 Page 8 of 11 This page shows the Modelica code of the new type. If you are familiar with the Modelica language you can also enter or edit the code here. Documentation On this page you can describe the functionality and the behavior of the new type. Now you have finished the creation process. Testing the new element type Let us now test the behavior of the new type. For this Drag&Drop the type newobject1 from the tree view of the model explorer to the model view. Add a mass from the Linear Mechanics and connect the two elements as seen in Figure 7. Figure 7: Model structure for testing Enter the following parameters to the elements: ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

9 Page 9 of 11 mass1 newobject1 Enable the protocol attribute for the Force of newobject1 Run a simulation and open the result window for the force of newobject1. Figure 8: Linear behavior of the Spring-Damper Change the settings of newobject1: newobject1 k_curve After entering the values for the displacement and the force select the Spline interpolation by pressing the button. ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

10 Page 10 of 11 b_curve After entering the values for the velocitiy and the force select the Spline interpolation by pressing the button. Figure 9: Nonlinear behavior of the spring-damper ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved

11 Page 11 of 11 Finally, let us resume a few points concerning the benefits of this tutorial You have learned how to create new element types by using the TypeDesigner. There is the option to add several components to a type for the later description of the behavior. With Boolean expressions and enumerations you can toggle the parameters, variables and other components of the type. The new types can include various behavior options which are selectable using Activity Groups. Inside the type the Modelica language is used. The handling of a user-defined type is the same as for the internal types. ITI and are registered trademarks of ITI GmbH Dresden. ITI GmbH, Dresden, Germany, All rights reserved