Project Title:

Miniature Rotary Actuator with Position Sensing

94-1	05.01	1992	B	

Miniature Rotary Actuator with Position Sensing

Abstract:

ORBITEC proposes to develop an innovative miniature rotary actuator 
with integrated position sensing. The actuator will occupy a small 
volume (< 1 in3) and yet develop torques typical of larger dc 
motors. The compact size of this actuator makes it ideally suited 
for application as joint actuators for dexterous end-effectors or 
as rotary joints in miniature robotic manipulators and commercial 
applications. Unlike other methods of joint actuation, this device 
requires no external motors, tendons or bulky mechanical 
interfaces. Rotary actuation rates are predicted as high as 110 rpm 
under no load conditions with corresponding static torques as high 
as 9 in-lb. More conservative estimates still yield an actuator 
comparable in output to existing methods at a fraction of the size 
and weight. Position sensing is provided by a fiber-optic rotation 
sensor under development that can currently resolve 1/10th of a 
degree with a sensor diameter of 1/8 in. The combination of the two 
technologies allows for an extremely small profile rotary actuator 
suitable for application where small size and high performance are 
required. The objective of the Phase I work is to prove feasibility 
of the actuator through component and subsystem testing. Phase II 
will involve full prototype development and delivery to NASA.

A small high output sensored rotary actuator is pertinent for small 
and micro-manipulators. The compact size allows for development of 
anthropomorphic robotics hands and miniature robotic manipulators 
for telerobotic servicing of orbital experiments. The rotary 
actuator can also be integrated into any hardware package where 
high output over a wide range of motion is required in a small size 
and low mass design.

Key Words

Orbital Technologies Corporation (ORBITEC) 
402 Gammon Place, Suite 200 
Madison, WI 53719