[en] The classical design techniques are based on the root-locus that utilize only the plant output for feedback with a dynamic controller. In this paper, we employ modern control designs that require the use of all state variables to form a linear static controller. Modern control design is especially useful in multivariable systems. One approach in modern control system accomplished by the use of state feedback is known as Pole-placement Design. The pole-placement design allows all roots of the system characteristic equation to be placed in desired locations. This result in a regulator with constant gain vector K. The state-variable feedback concept requires that all states be accessible in a physical system. For systems in which all states are not available for feedback, a state estimator (observer) may be designed to implement the pole-placement design.(author)