Plural motor apparatus for controlling the movement of an object

Claim 1

APPARATUS FOR CONTROLLING A MACHINE TOOL OF THE TYPE WHICH HAS AT LEAST TWO SLIDES, A FIRST SLIDE AND A SECOND SLIDE, AND AT LEAST TWO SLIDEWAYS, A FIRST SLIDEWAY AND A SECOND SLIDEWAY, UPON WHICH MACHINE TOOL THE FIRST AND SECOND SLIDES ARE RESPECTIVELY MOVABLE ALONG A FIRST PATH AND A SECOND PATH SUBSTANTIALLY AT RIGHT ANGLES TO THE FIRST PATH, SO AS TO PROVIDE RELATIVE MOVEMENT BETWEEN THE TOOL OF SAID MACHINE TOOL AND A WORKPIECE IN TWO ORTHOGONAL DIRECTIONS IN A PLANE, A FIRST SLIDE-MOVING MECHANISM FOR MOVING THE FIRST ALONG THE FIRST PATH, A SECOND SLIDEMOVING MECHANISM FOR MOVING THE SECOND SLIDE ALONG THE SECOND PATH, A CONTROL SYSTEM FOR CONTROLLING AT LEAST THE FIRST SLIDE-MOVING MECHANISM, SAID CONTROL SYSTEM COMPRISING MEANS FOR RECEIVING CONTROL SIGNALS CHARACTERISTIC OF A DESIRED RELATIVE MOVEMENT BETWEEN THE TOOL AND THE WORKPIECE ALONG THE FIRST PATH, MEANS FOR INDICATING THE POSITION OF THE FIRST SLIDE ALONG THE FIRST PATH AND SLIDE MOVEMENT CONTROL MEANS RESPONSIVE TO THE SIGNAL RECEIVING MEANS AND POSITION INDICATING MEANS FOR CONTROLLING THE FIRST SLIDE-MOVING MECHANISM ACCORDING TO THE SAID SIGNALS, THE SAID APPARATUS FURTHER COMPRISING DISPLACEMENT MEASURING MEANS HAVING AT LEAST ONE PAIR OF COOPERATING MEASURING ELEMENTS, ONE ELEMENT OF ANY SUCH PAIR BEING ATTACHED TO A FIRST PATH AND THE OTHER ELEMENT TO A SECOND PART, SAID TWO PARTS BEING INCLUDED IN A GROUP OF PARTS OF THE MACHINE TOOL WHICH PROVIDE A MECHANICAL LINKAGE FROM AND INCLUDING THE SECOND SLIDEWAY ON THE ONE HAND TO THE POINT OF CONTACT BETWEEN THE TOOL AND THE WORKPIECE ON THE OTHER HAND, MEANS FOR MEASURING RELATIVE MOVEMENTS BETWEEN THE SAID TWO ELEMENTS OF ANY ONE OF SAID PAIRS OF MEASURING ELEMENTS RESULTING FROM THOSE RELATIVE DISPLACEMENTS, OF THE MACHINE TOOL PARTS TO WHICH THE SAID ELEMENTS ARE ATTACHED, WHICH RESULT IN RELATIVE MOVEMENT BETWEEN THE TOOL AND THE WORKPIECE IN THE DIRECTION OF THE FIRST PATH, MEANS FOR GENERATING CORRECTION SIGNALS CHARACTERISTIC OF SUCH RELATIVE MOVEMENTS BETWEEN THE SAID ELEMENTS OF THE SAID ONE PAIR OF MEASURING ELEMENTS AND MEANS FOR APPLYING THOSE SIGNALS TO THE SAID CONTROL SYSTEM ASSOCIATED WITH THE FIRST SLIDE TO MODIFY THE EFFECT OF THE CONTROL SIGNAL RECEIVING MEANS AND THE POSITION INDICATING MEANS TO THE EXTENT AND IN THE SENSE REQUIRED TO COMPENSATE FOR THE SAID DISPLACEMENTS.