Direct drive motors
two planar servomotors with Hall-sensors feedback
Short design description of planar motor
Planar XY table consists of moving element called forcer which glides on the frictionless air bearings over the special "waffle-like "surface called stator. Planar forcer contains four or more
linear electromagnetic modules are perpendicular to each other. As motoring modules respond to varying currents, forcer moves across the stator.
Planar forcers are equipped with Hall sensor feedback (pitch period is 1 mm) and driven in closed loop.
Planar XY table can operate in any orientation (horizontal, side wall, upside-down). Multiple forcers can be installed and operated independently on a single stator for high
productivity and flexibility in many robotic automation applications. The maximal dimensions of stator is 1000x2000mm.
Possible fields of application
- Assembly operations in microelectronics
and instrument engineering;
- LSI and VLSI welding;
- Probe monitoring;
- Crystal fitting;
- SMD units assembly
- Printed circuit board control;
- Laser technological complexes;
- Measuring machines
dimensions of the forcer (LxBxH)
mm 146 x 154 x 23 175 x 320 x 30 154 x 184 x 28 214 x 236 x 30 380 x360 x 48 Weight Kg 1.4 3.7 1.7
12.0 Compressed air consumption (litr/min) 6 21 6.4 15 36.2 Rated current I A 3.0 3.0 3.0 3.0 6.0 Resistance R (Ohm) 0.8 1.5 0.8 1.0 0.4 Inductance (mH) L (mH) 1.9 3.6 1.9 2.0 0.9 Holding force coordinate X (FHX) and Y(FHY) N 70
Repeatability accuracy (micron) 3 3 3 3 3 Positioning accuracy (micron) ±25 ±10 ±10 ±10 ±10 Resolution (micron) 3 1 1 1 1 Attraction force , (N) Fz (N) 360 1000 560 200 200 Payload Ft, (N) 29 80 43 30 150 Moment Mbr Nm 3.2 19 5.8 1.5 56.4 Overall and join dimension files *.pdf
PLANAR MOTOR HOW IT WORKS
Planar motor consists of iron stator plate with tooth structure and forcer with two toothed iron
cores with permanent magnet and windings. All tooth structures are filled with epoxy and
precise grinded. Forcer has air nozzles to build air gapbetween forcer and stator by
Function of planar motor is similar to hybrid stepping motor. Permanentmagnet excites
magnetic flux in both iron cores. The fluxes produced by windings currents were added
or subtracted from such flux, result is maximal flux under one of forcer's toothes.
Such forcer's tooth will be moved to correspondent stator tooth (see picture).
Because forcers tooth's are shifted on half of tooth pitch for each core and tooth cores are
shifted on quarter of tooth pitch, quadrature changing of phase currents (like sin-cos) causes
continuous movement of forcer.
Such forcers structure is build for both perpendicular X and Y axes, and stator has chess
pattern tooth's, as result free movement any contour of XY plane is possible.
Planar servo motors additionaly has built-in position encoder based on two hall sensors,
excitated by additional permanent magnet. Such encoder sense tooth structure of stator
and produce sin-cos signals like standard 1Vpp encoders. These signals are evaluated by
servocontroller, position and velocity of motor is calculated, and motor is controlled as
AC servomotor with position feedback.