Nonlinear control encompasses control strategies designed for systems whose dynamics cannot be adequately described by linear differential equations. In robotics, virtually all manipulators and mobile platforms exhibit nonlinear behaviour due to inertia coupling, Coriolis terms, gravity loading, and joint friction. Nonlinear control techniques—including computed-torque control, sliding-mode control, feedback linearisation, Lyapunov-based methods, and model predictive control—explicitly account for these nonlinearities to achieve stable, high-performance trajectory tracking across the full operating envelope.