DP9.1 A mobile robot for toxic waste cleanup is shown in Figure DP9.1

(a) [23]. The closed-loop speed control is a unity feedback system. The Nichols chart in Figure DP9.1

(b) shows the plot of G j c( ) ω ω G j ( ) K versus ω.

The value of the frequency at the points indicated is recorded in the following table:

(a)