Apparatus for movement of an object

Apparatus for movement of an object, comprising:

• a) a driving mechanism for moving the object along multi-dimensional axes,
• b) a control unit coupled to the driving mechanism for controlling the movement of said object to a target position defined by positions along said multi-dimensional axes by repetitively generating steering signals to be applied to the driving mechanism, said control unit comprising processing means,
• c) error compensating means for compensating effects of errors in the driving mechanism, which errors cause a deviation between an actual position and the target position, said errors arising due to effects along the multi-dimensional axes from parameters affecting the driving mechanism including load, geometrical, and temperature conditions,
• d) said control unit comprising a source from which said effects of said errors in the driving mechanism are stored and can be retrieved, the control unit processing means being operative for computing error values taking into account the effects of said parameters on the error in positioning of an object along each of the multi-dimensional axes as a function of the object's position along each of the other multi-dimensional axes and storing same in the source,
• e) said control unit being integrated with said error compensating means and being operative to access said source during at least a substantial fraction of the repetitions of generating the steering signals and for retrieving from said source during each access the error values and using those error values in generating the steering signals that are applied to the driving mechanism.