Feedforwardcontroles

Feedforwardcontroles refers to a class of control strategies known as feedforward control, which aims to anticipate the effects of disturbances or reference changes and apply a corrective action before those effects appear in the system output. Unlike traditional feedback, which reacts to errors after they occur, feedforward uses models and measurements of anticipated perturbations to reduce or prevent the deviation from the desired performance.

How it works depends on having a sufficient model of the process and, ideally, measurements or estimates of disturbances or setpoint changes. A feedforward action is computed from these signals and applied to the plant in parallel with any existing control. In many designs, the feedforward and a conventional feedback loop operate together, often in cascade or parallel configurations, so the feedforward handles the known or measurable changes and the feedback corrects residual errors and unmodeled effects.

Key advantages include faster disturbance rejection, reduced reliance on feedback gains for transient performance, and the potential to lower overall error when disturbances are measurable. Limitations arise from the need for an accurate process model and reliable disturbance measurements; unmodeled dynamics or unmeasured disturbances can degrade performance or even destabilize the system if the feedforward path is poorly designed.

Common applications span process control, manufacturing lines, HVAC systems, robotics, and aerospace control where disturbances are predictable or measurable. Design considerations include model accuracy, disturbance estimation methods, and the interaction with any existing feedback controller to ensure robustness and stability. In practice, feedforwardcontroles are often used in concert with feedback to provide both proactive and corrective control.