HyVisual 10.0.1

Below are simple demonstrations of this modeler:

• Mode transitions in models of physical systems: StickyMasses.
  This example models a physical system consisting of two point masses on springs that stick together when they collide. It illustrates how to model systems when different modes of operation require different ODE models. There is also a Graphical Sticky Masses version that shows the model graphically.
  NOTE: This graphical model requires that you have installed Java 3D from Sun (see https://java3d.dev.java.net/).
• Simultaneous events: NewtonsCradle.
  This example illustrates a challenging hybrid systems modeling problem that requires correctly handling simultaneous events. The example is a classic mechanical toy called Newton's cradle, where suspended pendulums collide with one another. Multiple simultaneous collisions must be correctly handled.
  See also NewtonsCradleAnimated. NOTE: Requires Java 3D.
• Stochastic hybrid systems: HysteresisWithRandomDelay, HysteresisWithRandomLosses.
  This example illustrates how to model random delays and losses associated with state transitions of a hybrid systems.
• Event detection: LevelCrossingDetectorDetectsGlitches.
  This example illustrates that HyVisual correctly handles both continuous-time signals and discrete events, including multiple discrete events that occur at the same time. It also shows that a piecewise continuous signal has multiple values at the time of the discontinuity, and that these values are ordered.
• Discretely changing parameters: Thermostat.
  This example models a thermostat in a simple physical environment. It illustrates how to model systems when a single ODE model has parameters whose values change discretely.
• Zeno systems: BouncingBall.
  This example shows a bouncing ball model. Like the previous example, it has a single ODE model with parameters whose values change discretely. Unlike the previous example, however, it exhibits a so-called "Zeno condition," where the time between events gets arbitrarily small.
  There is also a Graphical BouncingBall. NOTE: Requires Java 3D.
• Switching continuous-time signals: Switch.
  This example shows a switch that selects from one of two continuous-time inputs. It illustrates how to model systems where continuous-time signals are mixed with discrete-event signals. Such systems are called "mixed-signal" systems.
• Modal control laws: CarTracking.
  This example shows a control system with two control laws, one for normal operation and one for degraded operation in the presence of faults. A modal model controls the switching between them.
  The FurutaPendulum demo is a graphical demo of a similar modal model. NOTE: Requires Java 3D.
• Linear time-invariant systems: SquareWave.
  This example shows a linear transfer function given as a rational Laplace transform, and its response to a square wave input. This model is not a hybrid system, but a classical continuous-time dynamical system.
• Chaotic systems: Lorenz.
  This example shows a nonlinear system constructed using integrators and expression actors in a feedback loop. Because of the nonlinearity, the system exhibits a form of chaotic behavior known as a strange attractor. This model is not a hybrid system, but a classical nonlinear continuous-time dynamical system.
• Sampling piecewise continuous and discrete signals: SampledClocks.
  This example illustrates that piecewise continuous signals in HyVisual can be sampled at their discontinuities, and that the behavior is consistent and predictable. Discrete signals can also be sampled with consistent and predictable behavior.
• Integrating with MATLAB: MatlabContinuous
  This example uses the MATLAB interface created by Zoltan Kemenczy and Sean Simmons, of Research in Motion Ltd., to plot a 3-D surface. This works only under Windows and only if Matlab is installed locally. In the 10.0.1 release, we ship with a shared library compiled against Matlab 6.5. If you have another version of Matlab, you may need to recompile from source. The Matlab interface requires that Cygwin is installed, and works with gcc-3.2, not gcc-3.3.
• Using function closures: Transmission
  This model shows a model of a car with a transmission. A transmission is generally used when an engine has a relatively narrow band over which the maximum power of the engine is available. In order to obtain high torque over a wider range of speeds, the engine is connected to a set of gears with different size ratios (the transmission). This model uses function closures to significantly simplify the model. The efficiency function used for this model can be seen in EfficiencyCurve.

This visual modeler is built using Ptolemy II, which is a software framework developed as part of the Ptolemy project at the University of California at Berkeley. See the Ptolemy Project web page for more information.