Actuator. Unconventional actuator systems

An actuator is a functional element which connects the information processing part of an electronic control system in a technical of nontechnical process. Actuators can be used to control the flow of energy, mass or volume. The output quantity of an actuator is energy or power, often in the form of a mechanical working potential (force times displacement). The actuator control is always achieved using very low electrical power, ideally without any power consumption. Actuators can be classified as conventional and unconventional actuators. Conventional actuators are commonly used as essential components for mechatronic systems) These are, for instance, electrical motors, pneumatic actuators, hydraulic pistons, or relays. Unconventional actuators are rather high integrated. They are not just an integral part of the system, they are a part of the structure itself combining sensing, actuation, and mechanical functions. Unconventional actuators are made of transducer materials. Piezoelectric actuators, shape memory alloy actuators, thermal bimorphs, and electroactive polymers are just a few examples of them.