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RSR100 Direct Drive Rotary Stage

The RSR100 is a low profile, high precision rotary stage driven directly by an integrated brushless motor in place of a mechanical worm gear or belt drive.  Benefits include no backlash, better positioning sensitivity, higher speeds, smaller envelope, and no drive wear and maintenance.  This makes the RSR’s well suited for applications that require high rotational accuracy, excellent positioning sensitivity and repeatability, and fast move and settle times.

For high torque and minimal heat output in a very compact stage the RSR100 is equipped with an ultra-thin, single slot, 24 pole motor with NdFeB magnets.  Internal Hall switches are included to support trapezoidal commutation, and with some controllers can also be used for sine commutation initialization and phase error checking.

Position feedback is provided by a high resolution, hysteresis free, non-contact encoder mounted directly to the rotary stage hub.  Multiple RS422A interpolation options are available with resolutions down to 0.021 arc-sec.  For very high resolution feedback without sacrificing speed an encoder with an analog 1 volt p-p output is available for interpolation by the controller.

A preloaded, matched angular contact bearing set gives the RSR100 good stiffness and load capacity within a very low profile.  This precision bearing set also gives the RSR its low axial radial runout errors, and low wobble errors.  Angular contact bearings have a long life, and are well suited to higher rotational speeds.

To accommodate routing of wires or vacuum lines, or an optical pathway, the RSR100 has a large, 2 inch open aperture.

Stage Specifications
Encoder Ring 15,744 Cycles per Revolution
Digital Encoder Resolution, RS422A 0.021 – 20.6 arc-sec
Analog Encoder Signal Period, 1Vp-p 82.32 arc-sec
Repeatability (@ 0.41 arc-sec resolution or finer) ±1.0 arc-sec
Rotational Accuracy ±20 arc-sec
Tilt Error (Wobble) 10 arc-sec
Radial Error (Eccentricity) 4µm
Axial Error 2µm
Load Capacity 10Kg
Maximum Velocity (Resolution Dependent) 240 rpm
Rotary Hub Inertia 0.0015Kg-m²
Stage Weight 1.6Kg
Motor Specifications
Torque Constant, Kt 0.31 N-m/amp pk Poles 24
Back EMF, Ke 32.5 v/krpm Resistance 2.5 Ω
Continuous Torque 1.6 N-m Inductance 5 mH
Continuous Current 5.0 amps pk Commutation Halls Internal
Encoder - Max Velocity (50MHz)
Resolution (arc-sec) Max Slew Rate (RPM) Quad Count Rate (Hz)
4.12 240 1,259,520
2.06 240 2,519,040
0.82 240 6,297,600
0.41 240 12,595,200
0.21 240 25,190,400
0.08 124 32,537,600
0.04 62 32,537,600


Step Chart for RSR100

RSR100 Rotary Stage Dimension Drawings