Terminology and Definitions

This subsection provides a list of terms that are used in the subsequent sections and their meaning, with the purpose of reducing ambiguity and making it easier to correctly understand the requirements.

  • PD Control Loop: Closed-Loop control system with PD Controller, Summing Point and Power Plant.
  • PD Controller: Proportional-Derivative Controller.
  • Summing Point: Control block where the difference between the Set-Point and the Process Variable is computed.
  • Power Plant: A second order system to be controlled.
  • Second Order System: A system whose input-output relationship is denoted by a second-order differential equation.
  • Process Error: Input to the PID controller. Process Error is the difference between the Set-Point and the Process Variable.
  • Simulation Time: Total execution time of the PD simulation.
  • Process Variable: The output value from the power plant.
  • Set-Point: The desired value that the control system must reach. This also knows as the reference variable.
  • Proportional Gain: Gain constant of the proportional controller.
  • Derivative Gain: Gain constant of the derivative controller.
  • Proportional control: A linear feedback control system where correction is applied to the controlled variable which is proportional to the difference between desired and measured values.
  • Derivative control: Monitors the rate of change of the error signal and contributes a component of the output signal (proportional to a derivative of the error signal).
  • Frequency domain: The analysis of mathematical functions in terms of frequency, instead of time.
  • Time domain: The analysis of mathematical functions in terms of time.
  • Laplace transform: An integral transform that converts a function of a real variable t (often time) to a function of a complex variable s (complex frequency).
  • Control Variable: The Control Variable is the output of the PD controller.
  • Step Time: Simulation step time.
  • Absolute Tolerance: Absolute tolerance for the integrator.
  • Relative Tolerance: Relative tolerance for the integrator.
  • Transfer Function: The Transfer Function of a system is the ratio of the output to the input functions in the frequency domain.
  • Damping Coefficient: Quantity that characterizes a second order system’s oscillatory response.
  • Stiffness Coefficient: Quantity that characterizes a spring’s stiffness.