There are many possibilities for the actuator drive mechanism besides the linear motors described herein. Those possibilities include lead screw drives, and belt drives, and piezoelectric linear motors. For less demanding applications, stepper motors will be used. The first product uses piezoelectric linear motors and air bearings for the actuators. The X-Y grid can be replaced by linear scales attached to each of the motor actuators.
Errors caused by temperature changes within the actuators also come back into play.
However all other accuracy benefits remain, and absolute accuracies in the sub-micron range will still be achieved in many cases. Inexpensive bearings could be used under the platform and at the motor contact points in place of air bearings or special low-stiction bearings. This would reduce the absolute accuracy that the servo could achieve, but it will still be possible to achieve micron level accuracies. If there is no requirement for rotation, one of the X-actuators can be eliminated. In that case, the one actuator would support all 4 x-axis edge bearings Beyond that, there are many other compromises that can be made to reduce cost when speed and accuracy can be traded off.