Dynamic simulation
Encyclopedia
Dynamic simulation is the use of a computer program to model the time varying behavior of a system. The systems are typically described by ordinary differential equations or partial differential equations. As mathematical model
s incorporate real-world constraints, like gear backlash (engineering)
and rebound from a hard stop, equations become nonlinear. This requires numerical methods to solve the equations. A numerical simulation is done by stepping through a time interval and calculating the integral of the derivatives by approximating the area under the derivative curves. Some methods use a fixed step through the interval, and others use an adaptive step that can shrink or grow automatically to maintain an acceptable error tolerance. Industrial uses of dynamic simulation are many and range from nuclear power, steam turbines, 6 degree of freedom vehicle modeling, electric motors, econometric models, biological systems, robot arms, mass spring dampers, hydraulic systems, and drug dose migration through the human body to name a few. These models can often be run in real time to give a virtual response close to the actual system. This is useful in process control
and mechatronic systems for tuning the automatic control
systems before they are connect to the real system, or for human training before they control the real system.
Simulation is also used in computer games and animation and can be accelerated by using a physics engine
, the technology used in many powerful computer graphics
software programs
, like 3ds Max, Maya
, Lightwave
, and many others to simulate physical characteristics. In computer animation, things like hair
, cloth, liquid
, fire
, and particles can be easily modeled, while the human animator
animates simpler objects. Computer-based dynamic animation was first used at a very simple level in the 1989 Pixar Animation Studios short film Knick Knack to move the fake snow in the snowglobe and pebbles in a fish tank.
The calculated values are associated with parameters of the rod and crank.
In this example the crank is driving, we vary both the speed of rotation, its radius and the length of the rod, the piston follows.
Mathematical model
A mathematical model is a description of a system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used not only in the natural sciences and engineering disciplines A mathematical model is a...
s incorporate real-world constraints, like gear backlash (engineering)
Backlash (engineering)
In mechanical engineering, backlash, sometimes called lash or play, is clearance between mating components, sometimes described as the amount of lost motion due to clearance or slackness when movement is reversed and contact is re-established...
and rebound from a hard stop, equations become nonlinear. This requires numerical methods to solve the equations. A numerical simulation is done by stepping through a time interval and calculating the integral of the derivatives by approximating the area under the derivative curves. Some methods use a fixed step through the interval, and others use an adaptive step that can shrink or grow automatically to maintain an acceptable error tolerance. Industrial uses of dynamic simulation are many and range from nuclear power, steam turbines, 6 degree of freedom vehicle modeling, electric motors, econometric models, biological systems, robot arms, mass spring dampers, hydraulic systems, and drug dose migration through the human body to name a few. These models can often be run in real time to give a virtual response close to the actual system. This is useful in process control
Process control
Process control is a statistics and engineering discipline that deals with architectures, mechanisms and algorithms for maintaining the output of a specific process within a desired range...
and mechatronic systems for tuning the automatic control
Automatic control
Automatic control is the application of concepts derived from the research area of modern control theory. Automatic control is also a technology for application of control strategies. The implementing requires prior of analyzing and modeling of the subject to be controlled...
systems before they are connect to the real system, or for human training before they control the real system.
Simulation is also used in computer games and animation and can be accelerated by using a physics engine
Physics engine
A physics engine is computer software that provides an approximate simulation of certain physical systems, such as rigid body dynamics , soft body dynamics, and fluid dynamics, of use in the domains of computer graphics, video games and film. Their main uses are in video games , in which case the...
, the technology used in many powerful computer graphics
Computer graphics
Computer graphics are graphics created using computers and, more generally, the representation and manipulation of image data by a computer with help from specialized software and hardware....
software programs
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
, like 3ds Max, Maya
Maya (software)
Autodesk Maya , commonly shortened to Maya, is 3D computer graphics software that runs on Microsoft Windows, Mac OS and Linux, originally developed by Alias Systems Corporation and currently owned and developed by Autodesk, Inc. It is used to create interactive 3D applications, including video...
, Lightwave
LightWave
LightWave 3D is a high end computer graphics program developed by NewTek. The latest release of LightWave runs on Windows and Mac OS X.- Overview:...
, and many others to simulate physical characteristics. In computer animation, things like hair
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....
, cloth, liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
, fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
, and particles can be easily modeled, while the human animator
Animator
An animator is an artist who creates multiple images that give an illusion of movement called animation when displayed in rapid sequence; the images are called frames and key frames. Animators can work in a variety of fields including film, television, video games, and the internet. Usually, an...
animates simpler objects. Computer-based dynamic animation was first used at a very simple level in the 1989 Pixar Animation Studios short film Knick Knack to move the fake snow in the snowglobe and pebbles in a fish tank.
Example of Dynamic simulation
This animation was made with a software system dynamics, with a 3D modeler.The calculated values are associated with parameters of the rod and crank.
In this example the crank is driving, we vary both the speed of rotation, its radius and the length of the rod, the piston follows.
See also
- AMESimAMESimLMS Imagine.Lab AMESim is a simulation software for the modelling and analysis of one-dimensional systems. The software package offers a 1D simulation suite to model and analyze multi-domain, intelligent systems and to predict their multi-disciplinary performance...
A software for simulating multi-domain dynamic systems - ModelicaModelicaModelica is an object-oriented, declarative, multi-domain modeling language for component-oriented modeling of complex systems, e.g., systems containing mechanical, electrical, electronic, hydraulic, thermal, control, electric power or process-oriented subcomponents.The free Modelica languageis...
A non-proprietary, object-oriented, equation based language for dynamic simulation - Physics enginePhysics engineA physics engine is computer software that provides an approximate simulation of certain physical systems, such as rigid body dynamics , soft body dynamics, and fluid dynamics, of use in the domains of computer graphics, video games and film. Their main uses are in video games , in which case the...
- VisSimVisSimVisSim is a visual block diagram language for simulation of dynamical systems and model based design of embedded systems. It is developed by Visual Solutions of Westford, Massachusetts....
A visual language for nonlinear dynamic simulation - EICASLABEICASLABEICASLAB is a software suite providing a laboratory for automatic control design and time-series forecasting developed as final output of the European ACODUASIS Project IPS-2001-42068 funded by the European Community within the Innovation Programme...
A software suite allowing nonlinear dynamic simulation - PottersWheelPottersWheelPottersWheel is a MATLAB toolbox for mathematical modeling of time-dependent dynamical systems that can be expressed as chemical reaction networks or ordinary differential equations . It allows the automatic calibration of model parameters by fitting the model to experimental measurements...
A Matlab toolbox to calibrate parameters of dynamic systems