Ultraprecise rotary actuator boosts torque and accuracy by a factor of four

March 25, 2013

Changchun, China--Ultraprecise positioning devices are used throughout photonics for positioning optics and other components; one of the challenges for rotational adjustment is providing sufficient torque through small, precise angles. Now, researchers at Jilin University have created a new rotary actuator that accurately delivers more torque than previous devices.¹

Like many other ultraprecise rotary actuators, the new device's action is driven by piezoelectric material. The researchers improved upon previous designs with a flexible gripper, clamping block, and rotor that integrate the driving and stopping action; the clamp can be moved to different distances from the rotor's center, providing more power and control of the driving forces.

In experiments, the actuator rotated at speeds up to 77,488 μrad/s at a driving frequency of 167 Hz, with a resolution and maximum load torque of 0.25 μrad and 37 N -mm, respectively. The researchers say these are approximately fourfold improvements over other piezoelectric actuators at the maximum driving frequency of the other devices.

However, while the new device can be driven at higher frequencies, the resulting higher speeds mean less accuracy because the rotor is harder to stop due to the additional rotational inertia of the rotor. The researchers are working on a new clamping design to overcome this limitation.

REFERENCE:

1. Hongwei Zhao et al., Review of Scientific Instruments 84, 015006 (2013); http://dx.doi.org/10.1063/1.4788736

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.