User manual MAPLESOFT MAPLESIM

[. . . ] MapleSim User's Guide Copyright © Maplesoft, a division of Waterloo Maple Inc. 2001-2009 MapleSim User's Guide Copyright Maplesoft, MapleSim, and Maple are all trademarks of Waterloo Maple Inc. No part of this book may be reproduced, stored in a retrieval system, or transcribed, in any form or by any means -- electronic, mechanical, photocopying, recording, or otherwise. Information in this document is subject to change without notice and does not represent a commitment on the part of the vendor. [. . . ] By using the Custom Component Template, which is a Maple worksheet available through the MapleSim document folder dialog box, you perform the following tasks in Maple to create a custom component: · · · · Define the component equations and properties that determine the behavior of the component (for example, parameters and port variables) Test and analyze your mathematical model Add ports to the component and define the associated port variable mappings Generate the component and make it available in MapleSim The Custom Component Template contains pre-built controls that allow you to perform these tasks. Each generated custom component is associated with a particular template and each template can be associated with one . msim file at a time. 47 48 · 3 Creating Custom Modeling Components 3. 2 Opening Custom Component Examples The following custom component examples are available with your MapleSim installation: · · · · Custom component defined with an algebraic equation A sample DC motor component defined with a differential equation A sample nonlinear spring-damper component Custom component defined with a transfer function To open an example: 1. In the Browse Templates dialog box, open the Component Templates folder. Select the example that you want to open, and click Attach Template. . . In the document list, select the template entry and click Open Selected. ) in the main toolbar. 3. 3 Example: Nonlinear Spring-Damper Component In this example, you will use the Custom Component Template to create a nonlinear springdamper custom component. The equations defined in this example are based on the Translational Spring Damper component in MapleSim. In this case, the stiffness and damping coefficients are replaced with input functions to the component. To obtain the governing relationships, you can start with a free-body diagram. The diagram for the spring-damper system is shown below. 3. 3 Example: Nonlinear Spring-Damper Component · 49 The end points, a and b, can be defined as the ports for the component; the equations are derived relative to these ports. Therefore, the general equation of motion, where is the damping coefficient, is the stiffness of the spring, and and , can be written as is the relative displacement between the two ports Also, an examination of the net force on the system shows that , where All of the above relationships are required to define the system behavior. Opening the Custom Component Template To start, open the Custom Component Template from the MapleSim document folder dialog box. In MapleSim, open the model to which you want to add the custom component. Click the document folder button ( ) in the main toolbar. 50 · 3 Creating Custom Modeling Components 3. Enter Nonlinear Spring-Damper as the name for the template and click OK. 6. In the document list, select the Nonlinear Spring-Damper entry and click Open Selected. The Custom Component Template is opened in Maple. Defining the Component Name and Equations You can now specify the name that will be displayed for the component in the MapleSim interface, a variable to store the equations, and the equations. To define the component equations, you create a system model by using commands from the DynamicSystems package. For more information, see the ?DynamicSystems topic in the Maple help system. In the Component Description section of the template, specify a component name called NonLinearSpringDamper. In the Component Equations section, delete the default equations below the table that defines the variables. > > 3. 3 Example: Nonlinear Spring-Damper Component · 51 > Note that the equations are entered in a Maple list. The constants, (damping) and (stiffness) are replaced by the functions and to define them as input states to the system. [. . . ] You will also assign a different length value to the connecting rod element. Click Main in the navigation toolbar to browse to the top level of your model. In the Inspector tab, in the Component field, change the name of the subsystem to Crank. From the Library Models palette, drag the Link icon to the model workspace and place it to the right of the subsystem. [. . . ]