Digital Control System for Detenting a DC Servomotor
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
A digital control system uses a microprocessor (MP) 20 to correct for drift from and to maintain a DC servomotor 10 at a zero or standstill position. The control system includes applying a plug brake to restrain drift of motor 10 after a detent correction operation and/or periodically applying an anti-drift pulse after a number of successive detent correction operations have occurred. The control system has particular application to the DC servomotors used for driving a paper carriage in a line printer where the print paper must be maintained at an accurate line position during printing. As seen in the drawing, a DC servomotor 10 is connected between upper power transistors 11 and 12 and lower power transistors 13 and 14 connected in an H-drive network 15. Network 15 includes upper diodes 16 and 17 and lower diodes 18 and 19.