Please help me with these questions from the book \"System Dynamics - Modeling,
ID: 2997078 • Letter: P
Question
Please help me with these questions from the book "System Dynamics - Modeling, Simulation, and Control of Mechatronic System 4th/5th edition"
1-1. Suppose you were a heating engineer and you wished to consider a house as a dynamic system. Without a heater, the average temperature in the house would clearly vary over a 24-h period. What might you consider for inputs, outputs, and state variables for a simple dynamic model? How would you expand your model so that it would predict temperatures in several rooms of the house? How does the installation of a thermostatically controlled heater change your model?
1-4. In the steady state a good weather vane points into the wind, but when the wind shifts, the vane cannot always be trusted to be pointing into the wind. Identify inputs, outputs, and the parameters of the weather vane system that
affect its response to the wind. Sketch your idea of how the position of the vane would change in time if the wind suddenly shifted 10-degree?
Explanation / Answer
Dynamic simulation (or dynamic system 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 models incorporate real-world constraints, like gear backlash 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. Some methods can use different time steps in different parts of the simulation model. 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.