Servocontrol

Servocontrol refers to a closed-loop control method used to drive a servo mechanism to reach a desired position, velocity, or torque with high precision. The system continuously compares the actual output to a commanded reference and uses the resulting error to adjust the actuator input, reducing error over time.

A typical servocontrol system comprises an actuator (often a servo motor or electric motor combined with gearing), a feedback sensor (such as an encoder, resolver, or potentiometer), a power amplifier, and a controller. The controller computes a control signal from the error and, in modern systems, may implement a proportional-integral-derivative (PID) or other advanced control law. The sensor provides real-time measurements of the output state, enabling closed-loop correction.

Control loops are usually nested: a fast inner loop regulates position or speed, while outer loops manage higher-level objectives. Controllers can be discrete or analog, and digital implementations sample signals and perform numerical calculations. Performance metrics include accuracy (steady-state error), response time, overshoot, stability margins, and bandwidth.

Applications span robotics, CNC machines, aerospace control surfaces, industrial automation, and consumer devices such as camera autofocus. Design considerations include nonlinearities, friction, backlash, gear stiffness, sensor noise, and safety constraints. See also PID control, servo motor, and feedback control.