| 摘要 |
774,517. Electric control systems. GENERAL ELECTRIC CO. April 21, 1953 [April 30, 1952], No. 10918/53. Class 40 (1). In a curve following arrangement in which a table 3, which may be the transmitter of a selsyn control system for a milling machine, carries a conducting wire 4 supplied with alternating current, and is driven under a tracking head 6 carrying first and second pairs of coils, in which are derived first and second error signals E1, E2, the first pair 11, 13 being situated at the front and rear along the line and the second pair 12, 14 straddling the curve, heading of the head with respect to the curve is controlled in response to the first signal E1, and lateral deviation is corrected by means of component drive signals derived from the second error signal E2 through a resolver and applied to motors X, Y to cause relative motion of the table and head in two inclined directions reducing the error to zero. In the copymilling machine shown the first error signal after amplification and rectification operates motor 19 directly to rotate the tracking head and drive the resolver rotor. The amplitude of a signal at mains frequency is modulated in accordance with the phase and amplitude of the second error signal E2 and the modulated signal fed to one winding of the rotor while a further mains frequency signal the amplitude of which may be varied to alter the normal speed of the motors is applied to a second winding in space quadrature to the first. The outputs of two stator windings in space quadrature are applied to X and Y motors respectively and the motion of the table is communicated to a table 24 carrying the workpiece 1 via the selsyn control system and gearing shown. The wire 4 may be supplied with a current at high frequency instead of mains frequency. |
