Actuating

Actuation is the process of converting energy into mechanical motion or force to perform work. An actuator is the device that performs actuation, responding to a control signal or input to produce displacement, velocity, torque, or force. Actuation is a central function in automated systems and control engineering, linking electrical, hydraulic, pneumatic, or thermal energy sources to mechanical output.

Major actuation technologies include electric actuators (such as DC motors, servo motors, and stepper motors) that convert electrical energy to rotational or linear motion; hydraulic actuators that use pressurized fluid to generate high force and linear movement; and pneumatic actuators that use compressed air for fast, moderate-force linear actuation. Other classes include piezoelectric and shape memory alloy actuators for precise or rapid micro-displacements, as well as magnetic, electroactive polymer, and hybrid solutions. Many systems combine several actuation methods or use integrated power electronics and control.

Design and performance considerations include force or torque, displacement (stroke), speed, precision, efficiency, and controllability. Real-world actuators exhibit nonlinearity, backlash, stiction, and leakage, which often necessitate feedback for accuracy. Closed-loop control uses sensors such as encoders, linear scales, or position sensors to regulate output; open-loop actuation relies on known input without feedback. Environmental conditions, temperature, vibration, and duty cycle affect performance and lifetime.

Applications span robotics, automated manufacturing, aerospace and automotive actuation, valve and damper control, process industries, CNC machines, and consumer devices. Selection among actuator types depends on load requirements, required speed and precision, available energy, duty cycle, environmental constraints, safety considerations, and maintenance needs.