MSDD Instructional Help
This page provides detailed instructions on the use of MSDD.
A control panel full of buttons can be found at the top of the MSDD's main applet panel. These buttons are arranged as Simulaton Control buttons and Animation Control buttons. The following table of links represents these controls.
Simulaton Controls Animation Controls
Help(opens this page)
Below the control panel is the Animation Canvas. Here the user sees an animated picture of a mass attached to a fixed reference point with a spring and a damper. Next to the mass, spring and damper is a set of axies where plots of the calculated solution are displayed.
The "Calculate Solution" button brings up the "Solutions Frame". This frame allows users to name a data set so that the user can refer to that particular calculation later. Any valid string can be used as a name for a data set. A button labled "Modify Solver Parameters" opens the Modify Solver Parameters Frame. Note that when the calculation of a solution is initiated, the calculate solution button changes its label to "Interrupt Calculation". If the calculation is interrupted, no data will be saved.
The "System Parameters" FrameThe quantities that make up the "system parameters" are the mass of the block, the spring constant of the spring and the damping constant of the damper. This frame allows for users to select from predifined systems or modify the systems parameters to thier own liking. The section labeled "Linear Systems" allows the user to select fom a under damped, a critically damped or a over damped system. The section labeled "Nonlinear System" will be developed in a future version.
The "Modify System Parameters" Frame
The quantities that make up the "system parameters" are the mass of the block, the spring constant of the spring and the damping constant of the damper. The user can enter thier own constants here. Note that the contants cant be negitive or zero.
The "Modify Solver Parameters" Frame
This frame gives the user the ability to set the initial position and velocity, the start and stop time and the number of time steps used in the calculation of a solution. Note that the start and stop time must be non-negitive numbers. Further, there are constraints on the selection of the number of steps used in the calculation of a solution. The determination of the minimum number of steps is influenced by factors such as the time duration of the solution, the bandwidth of the linear system and the applied input frequency.
The "Function Generator" Frame
The function generator frame enables the user to select from a number of input signals. The default input signal is a constant signal. Other signals that can be selected are a sine wave, a square wave and a chirp signal. Note that these signal's frequencies are specified in radians per second. Further, the chirp signal has as its instantanious frequency, the start frequency at the start time and the final frequency at the stop time. This instantanious frequency changes in a linear fashion.
In addition, more than one input signal can be selected at once.
This button initiates an animation that can be viewed on the Animation Canvas. Note that once an animation has been initiated, the label on this button changes to "Interrupt Animation" so that an animantion can be stopped. Further, a data set must be loaded prior to the initiation of an animation.
The button labeled "Saved Animations" opens this frame. This frame allows the user to select from previously named data sets.
The "I/O Summary" Button and the "Show Frequency Domain" Button
The "I/O Summary" Button and the "Show Frequency Domain" Button are actually the same button. This button changes its label according to the type of data set currently selected. When a data set has been generated when the forcing function is a chirp signal, this button is labeled "Show Frequency Domain". Otherwise, this button is labeled "I/O Summary". When clicked, it opens one of 2 frames designed to give the user some more insight into the properties of the mass, spring, damper system.
This frame is available when the input signal is not a sine sweep.
This frame shows a summary of the signals that are related to a particular simulation. The signals are split into four subpanels. On the left is the time domain signals and on the right is the frequency domain signals. Further, the top two panels represent the input signal and the bottom two panels represent the output signal.
This frame is available when the input signal is a sine sweep
This frame is intended to be viewed at the same time a user is viewing the sweep on the Animation Canvas. The frequency domain frame shows a plot of the Transfer Function over a frequency range of "stop frequency" minus "start frequency". A small graphical arrow drawn below the Transfer Function indicates a sine function at the instantanious frequency. The user can gain understanding of resonance phemonena by relating the sine wave's instantanious frequency to the eratic oscillations viewed in the Animation Canvas.