Question

Figure below shows the Bode diagram of an open-loop transfer function G(s)H(s) that is part of a closed- loop control system. The open-loop transfer function contains a lead controller with a control gain setting of K = 2, which corresponds to the Bode diagram below. Estimate the gain and phase margins and the control gain Kms that drives the closed-loop system to the point of marginal stability.

Fig: 1

Fig: 2