What is lambda tuning and when is it preferred over Ziegler-Nichols?

Lambda tuning (Internal Model Control) provides user-specified closed-loop time constant (lambda), allowing tradeoff between response speed and robustness. For first-order plus dead time process: Kc = T/(K*(lambda + L)), Ti = T, Td = 0 (PI controller). Lambda is typically set to 1-3 times the dead time. Lambda tuning is preferred when: conservative, non-oscillatory response is needed, process has variable characteristics, or safety requires robust stability. It produces less aggressive tuning than Ziegler-Nichols with better robustness to process variations.