Question

What are the basic consequences of the presence of nonlinearity in control systems ?

Answer 1

• Due to nonlinearity, we can not apply the superposition principle(linearity and homogeneity) as a result all the linear mathematical tools like Laplace transform, Fourier transform,z transform, Bode plot, root locus and Nyquist stability criteria fails.
• so analysis of the non-linear system is rigorous, complex, less general, often applying to only narrow categories system. These include limit cycle theory, Poincaré maps, Lyapunov stability theory, and describing functions.
• Nonlinear systems are often analyzed using numerical methods on computers.