A photovoltaic system is mounted on a space station in order to develop the power for the station. The photovoltaic panels should follow the Sun with good accuracy in order to maximize the energy from the panels. The unity feedback control system uses a DC motor, so that the transfer function of the panel mount and the motor is

We will select a controller G_c (s) assuming that an optical sensor is available to accurately track the sun’s position. The goal is to design G_c (s) so that (1) the percent overshoot to a step is P.O. ≤ 10% and (2) the steady-state error to a ramp input is e_ss ≤ 1%. Determine the best phase-lead controller. Examine the robustness of the system to a 10% variation in the motor time constant.

G(s) = 1 s(s+20)*