Actuators

The actuator , even actuators called, is a branch of drive technology that deals with the actuator employed as a technical element. The term “actuators” generally includes the generation of a movement or a deformation and is therefore of importance for various technical disciplines, for example in control engineering , automation technology or mechatronics .

Actuators convert signals (e.g. commands from the control computer) into mechanical movement or other physical quantities (e.g. pressure or temperature ) and thus actively intervene in the process.

In the classic sense, actuators can be any kind of movement generation:

• Mechanical : turning a steering column by hand
  • Pneumatically by means of a pneumatic cylinder
  • Hydraulically by means of a hydraulic cylinder
• Electromechanical : Rotation of a shaft , nut or threaded spindle by an electric motor that serves as a drive element or translation of the moving components of a linear system
• Biological : stimulation of a muscle fiber
• optical : display elements
• thermal : heaters, Peltier elements or flat thin bending actuators based on shape memory alloys

The user interface of electromechanical actuators is often a wired remote control or a radio remote control .

A specialization of actuator technology as a science has taken place in recent years.

Actuator systems based on shape memory alloys create new possibilities and offer advantages u. a. with regard to installation space and weight:

• Flat bending actuators, in which shape memory alloy wires are integrated into a fiber plastic composite , can achieve a deflection in the range of a few millimeters to several centimeters, depending on their size.
• A few millimeters of movement are realized in the area of micro-actuators . Here, for example, shape memory alloys are used, which have a high power density.

New piezoelectric composite materials allow the detection and generation of movements in a new way:

• Creation of movement: An electric field is applied to a piezoelectric composite material in a defined polarization direction: the result is targeted deformation (contraction, elongation, shear). Applications e.g. B. Pumps without a motor (principle similar to the human esophagus)
• Detection of movement: A force deforms the piezoelectric element and thus causes a potential difference proportional to the deformation. Application: Active and / or adaptive vibration control, noise reduction, increasing the positioning accuracy of highly dynamic systems.

Web links

• Fraunhofer-Gesellschaft - Alliance for Piezo Fiber Composites

Individual evidence

1. ↑ Intelligent material can improve aerodynamics. April 17, 2018, accessed November 22, 2019 . 
2. ↑ Lagoudas, Dimitris C .: Shape memory alloys: modeling and engineering applications . Springer, New York 2008, ISBN 978-0-387-47685-8 .
3. ↑ Microactuators: Linear and rotary “motors” made from one piece of metal | VDI specialist media. Retrieved June 11, 2019 .