Coordinate measuring apparatus and method for controlling the same

A method for controlling a coordinate measuring apparatus including a control system and a probe head having a probe pin movably attached thereto, the method comprising the steps of:

• control driving said probe head and said probe pin in accordance with desired data (Pi) so as to cause said probe pin to touchdown and liftoff of a surface of a workpiece to be measured at a plurality of points;
• and,
• guiding said probe head along an arcuately-shaped path
• (a) before the first touchdown;
• or,
• (b) between liftoff and renewed touchdown;
• or,
• (c) after the last liftoff;
• from the workpiece surface preparatory to a change of direction of said probe head.

A coordinate measuring apparatus for measuring a workpiece having a surface, the coordinate measuring apparatus comprising:

• a probe head having a probe pin movably attached thereto;
• a control system for control driving said probe head in accordance with desired data (Pi) so as to cause said probe pin to touch down or lift off said surface of said workpiece;
• said control system including a function component group functioning to compute a path (Si) from said desired data (Pi);
• and,
• said path (Si) being travelled by said probe head during a measuring operation of said workpiece and being computed by said function component group so as to cause an angle (.alpha.down, .alpha.up) conjointly defined by the direction of movement (vres) of said probe head at touchdown or liftoff and the projection (vproj) of said direction of movement on a plane tangent to said surface at the point (Pdown, Pup) of said touchdown or said liftoff to be less than 30.degree..

A coordinate measuring apparatus for measuring a workpiece having a surface, the coordinate measuring apparatus comprising:

• a probe head having a probe pin movably attached thereto;
• means for supplying desired data (Pi);
• a control system for control driving said probe head in accordance with said desired data (Pi);
• said control system including a function component group functioning to compute from said desired data (Pi) a path (Si) which is to be travelled by said probe head during a measuring operation of said workpiece;
• said function component group being adapted to compute said path so as to cause said probe head to move on an arcuately-shaped path;
• (a) before the first touchdown;
• or,
• (b) between liftoff and renewed touchdown;
• or,
• (c) after the last liftoff;
• from the workpiece surface preparatory to a change of direction of said probe head.