What is a Voice Coil Actuator?
Understanding the Basics of a Voice Coil Actuator
A voice coil actuator, also known as a non-commutated DC linear actuator, is a type of direct drive linear motor. The name “voice coil” comes from one of its historically first applications: vibrating the paper cone of a loudspeaker. They are currently used for a wide range of applications, including moving much larger masses. It consists of a permanent magnetic field assembly (permanent magnets and ferrous steel) and a coil assembly. The current flowing through the coil assembly interacts with the permanent magnetic field and generates a force vector perpendicular to the direction of the current. The force vector can be reversed by changing the polarity of current flowing through the coil.
A non-commutated DC linear actuator, typically referred to as a voice coil, is capable of a displacement of up to 5 inches, whereas most actuators have displacements up to 2 inches. Voice coils come in a range of sizes, from devices that generate a few ounces of force, to others that generate several hundred pounds of force. In addition, voice coil actuators can move bi-directionally, have a constant force over the stroke, and can be used for either open loop applications or closed loop position or force applications.
A voice coil actuator generates a force based on an interaction of current carrying conductors in a permanent magnetic field. The force generated by the voice coil is proportional to the cross product of the current flowing through the coil and the magnetic flux in the permanent magnetic field, as dictated by Lorentz’ force equation:
F = B x I where: F= ...