Stellglieds

Stellglieds (singular Stellglied) is a device in automation engineering that converts a control signal into a corresponding physical output to influence a plant variable. In control loops, Stellglieder are the actuating elements that effect changes in the system, such as opening a valve, moving a piston, or adjusting a lever. They receive a manipulated variable from a controller and produce a mechanical quantity, often in conjunction with a sensor for feedback to close the loop.

There are several common types of Stellglieder. Electric actuators convert electrical energy into linear or rotary motion and may include feedback devices such as encoders or potentiometers for precise positioning. Hydraulic actuators use fluid pressure to generate high force and stiffness, suitable for high-load applications. Pneumatic actuators, driven by compressed air, provide fast movement and simple construction but typically offer less positional accuracy. Modern Stellglieder often integrate position sensing, control electronics, and communication interfaces, enabling closed-loop operation and easier integration into automation networks.

Key performance characteristics include travel or stroke, force or torque, speed, resolution, and dynamic response. Electric actuators typically offer high precision and controllability, hydraulic actuators handle large forces, and pneumatic actuators provide rapid motion with simpler maintenance. The selection depends on required accuracy, speed, load, environment, and cost.

Stellglieder are fundamental in industrial automation, robotics, process control, and machine tools. They operate either in open-loop arrangements for simple tasks or in closed-loop systems where feedback from sensors improves accuracy and repeatability. The standard German plural is Stellglieder; Stellglieds is encountered in some usages but is generally considered nonstandard.