L-Series linear actuation product

The L-Series is a family of linear servo actuators from Ultra Motion, electromechanical actuators with integrated brushless DC control electronics for aerospace, defense, industrial and maritime use. The page for the L-Series and its L2 variant describes them as designed for dynamic operation in harsh environments, with a compact form for small installation spaces.

A brushless DC motor of high power density, combined with a planetary gearhead, drives each actuator. Power passes through a spur geartrain to a precision-ground, preloaded ballscrew, and a duplexed angular contact bearing takes all thrust loads. The preload gives zero axial backlash, which improves stiffness and control authority in position loops. The stated performance range is peak forces up to 1250 lbf and peak speeds up to 5 in/s, with standard strokes of 1.75 in, 3.125 in and 7.5 in. Mass is 3.05 lbm for the 3.125 in stroke.

Control is digital. The actuator offers CAN 2.0B and RS-485 serial command modes, which give full control of position and phase currents and return telemetry on the health and state of the unit. Position feedback comes from a contactless absolute sensor, called Phase Index by the maker, so the actuator knows its stroke position directly at power-up without a homing move. An optically isolated enable input works as a hardware disable, cutting power to the motor bridge while inactive and bypassing the onboard control electronics.

Redundant versions are available for tolerance to a single electrical fault, built from two motors, two sets of control electronics and a position sensor with three elements used for voting. The redundant channels are fully isolated electrically and do not communicate with each other. The host decides how to use them, in cold standby or load sharing, and no arbitration or voting is done by the actuator.

Electrical and environmental data are as follows: operating voltage 10 to 36 VDC, absolute maximum 62 VDC, operating temperature -40 to +100 degrees C, IP67 sealing with O-ring sealed joints and a spring-energised PTFE shaft seal. Surfaces are chem-filmed for continuous electrical enclosure and EMI/EMC protection. The electrical interface is a Series-5 D38999 connector carrying power, ground, enable, CAN and RS-485 lines. Vacuum modifications and customisation are available.

The listed applications on uncrewed aerial vehicles are swashplate and tail-rotor control and fixed-wing control surfaces. Further uses are utility actuation, and rudder control and accessory deployment on uncrewed surface vehicles.