ABSTRACT
This chapter reviews the concepts of control theory that are needed for our controller designs. Systems can often be described by second-order differential equations, and the second-order linear system characteristics are considered dominant in their dynamic nature. The zero position is chosen at the static equilibrium, where the weight is counterbalanced by a spring force. The response of the dynamic system to a step input is essential, and provides information on the stability of the system as well as the transient behavior to reach a steady state. The transfer function is specified by numerator and denominator, and the transient response is defined by the block of unit step response, in which the sampling time and length of time period are specified. The system is critically damped and gains its final position in the shortest possible time without oscillation.
