Simulation and Modelling - Old Questions

6.  What do you understand by interactive and feedback system in simulation? Explain.

Interactive System

Interactive systems are computer systems characterized by significant amounts of interaction between humans and the computer. Editors, CAD-CAM (Computer Aided Design-Computer Aided Manufacture) systems, and data entry systems are all computer systems involving a high degree of human-computer interaction. Games and simulations are interactive systems. Web browsers and Integrated Development Environments (IDEs) are also examples of very complex interactive systems.

Feedback System

The system takes feedback from the output i.e. input is coupled with output. A significant factor in the performance of many systems is that coupling occurs between the input and output of the system. The term feedback is used to describe the phenomenon.

One example of feedback system in which there is continuous control is the aircraft system. Here the input is a desired aircraft heading and the output is the actual heading. The gyroscope of the autopilot is able to detect the difference between the two headings. A feedback is established by using the difference to operate the control surface. Since change of heading will then affect the signal being used to control the heading.

The difference between the desired signal θ_t and actual heading θ₀ is called the error signal, since it is a measure of the extent to which the system from the desired condition. It is denoted by є.

We also know that, in terms of angular acceleration

From equation (1), (2) & (3)

Dividing both sides by I, and making the following substitutions in equation (4)

 (where  is damping factor)

    This is a second order differential equation.