<html>
<head>
<style><!--
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 12pt;
font-family:Calibri
}
--></style></head>
<body class='hmmessage'><div dir='ltr'><br>Hi; <br><br>Is it possible to model a damped-nonlinear pendulum under external excitation by using Coselica blocks? <br><br><br>Suppose we have a simple pendulum with a bob of mass "m" and a weightless rod of length "L". <br>The following 2nd-order ODE describes the motion of the pendulum: <br><br>"$ \ddot\theta + \frac{c}{mL^{2}}\dot{\theta}(t) + \frac{g}{L} \sin {\theta(t)} = \frac{\tau (t)}{mL^{2}} <br> $"<br><br>g: the gravitational acceleration (9.81 m/s^2)<br>ct: the (rotational) damping constant (due to air resistance and friction of the rod at its pivot point)<br>tau(t): the external torque applied to the pendulum<br><br>The attached files show how we can use Scilab ode function and Xcos blocks to solve the pendulum's ODE. <br>So my question is, <br>How can I solve this problem by using Modelica "standard"blocks? <br>I'm debating whether or not I should write my own Modelica blocks. <br><br><br>Merci, <br>Mehran<br>_<br><br><br> </div></body>
</html>