What is the purpose of system identification in control design?

• A. To calibrate sensors to a fixed reference.
• B. To develop a mathematical model of the plant from input-output data, enabling controller design, tuning, and simulation.
• C. To design the mechanical layout of the system.
• D. To log maintenance events for future audits.

Answer: (B)

Building a mathematical model of the plant from input-output data is the main goal of system identification. By applying known inputs and observing the outputs, you estimate the system’s dynamics and structure, yielding representations like transfer functions or state-space models. With a good model in hand, you can design controllers that achieve desired performance, tune controller parameters more effectively, and run simulations to predict how the closed-loop system will respond before making changes on real hardware. Other tasks—calibrating sensors, designing the mechanical layout, or logging maintenance events—serve measurement accuracy, hardware design, or record-keeping, not the process of uncovering the plant’s dynamic behavior from data.