Control for coordinate measuring instruments

Claim 1

A control system for a multi-coordinate measuring machine having an individual drive for each of a plurality of coordinate-component directions, said system comprising: a velocity-control circuit for each of said drives; a control unit for simultaneously controlling at least two of said drives; a scanning probe head movable along a path determined by said drives, said head including a probe pin that is deflectable in each of the coordinate-component directions, and plural measuring transducers for generating separate output signals which are proportional to the respective coordinate-component directions of probe-pin deflection, whereby during driven probe-head displacement with said probe pin in continuous contact with a workpiece, the output signals of said transducers are indicative of the respective component directions of path deviation with respect to workpiece contour; input means coupled to said control unit for inputting a preselected magnitude |V des . | of path velocity; said control unit including calculating means connected to said input means and to said transducers for freshly computing control-path velocity as the vector sum of instantaneous path velocity V 1 and a vector A e corresponding to the vector sum of said transducer-output signals, with the magnitude of the computed control-path velocity corresponding to said preselected magnitude; said calculating means having separate output connections supplying velocity-component values to the respective velocity-control circuits; and force-producing means in said probe head for producing a deflection-independent force of workpiece contact by said probe pin, wherein said force is substantially perpendicular to the instantaneous direction of path velocity.