COBEM99

S22 Mecatrônica

Title:

DESIGN AND FABRICATION OF A MECHATRONIC INDEXING HEAD

Summary :

ABSTRACT. IN THIS WORK, A NOVEL MECHATRONIC ANGULAR INDEXING DRIVE HAS BEEN DESIGNED, BUILT AND TESTED. TWO STEPPING MOTORS DRIVING TWO WORMS ENGAGED TO THE SAME GEAR ARE USED FOR THE INDEXING. ONE OF THE STEPPING MOTOR IS USED FOR THE ACTUAL INDEXING WHILE THE OTHER IS USED TO ELIMINATE THE BACKLASH AND TO LOCK IT IN PLACE. DURING INDEXING, THE LOCKING WORM IS RELEASED SO THAT THE DRIVE CAN BE TURNED WITH MINIMUM FRICTION. IN THIS WAY, HIGH REPEATABILITY WAS ACHIEVED BY ELIMINATING THE EFFECTS OF BOTH BACKLASH AND THE HIGHLY NON-LINEAR FRICTION. THE DRIVE WAS CALIBRATED ON A HIGH PRECISION (1 ARC-SECOND ACCURACY) "ZEISS" ANGULAR DIVIDING HEAD (1987). THE PERIODIC MEASURED ERROR WAS MODELED BY DECOMPOSING IT INTO ITS FOURIER COMPONENTS. A CORRECTING ALGORITHM USING THIS MATHEMATICAL MODEL WAS INCORPORATED INTO THE DRIVE SOFTWARE OF THE CONTROLLING MICROCOMPUTER. A SIX-FOLD IMPROVEMENT IN REPEATABILITY (OR PRECISION) WAS ACHIEVED; THE STANDARD DEVIATION OF THE ERROR, BASED ON 250 TEST RUNS, WAS REDUCED TO ONLY 14.8 SECONDS. KEY WORDS: MECHATRONIC DIVIDING HEAD, CNC INDEXER, DESIGN, FABRICATION, VERIFICATION

Author :

Góes, Luiz C. S.
Santos, José F. dos
Tu, Carlos C. C.
Ueno, Jorge 0

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