| 摘要 |
PURPOSE:To increase the low-band gain of a carriage servo to improve a disturbance eliminating capacity, by adopting a direct drive system as the drive transmitting system of a carriage and providing means which detect tracking and carriage error respectively. CONSTITUTION:In the current-displacement conversion frequency characteristic of a carriage motor 14, the phase characteristic is -180 deg. independently of frequency as shown in Fig. (a), and a servo band can be set freely by phase advancing compensation. When this servo band is set near a low-band resonance frequency f0 of an actuator 16 in Fig. (b), the overall open loop characteristic of both servos becomes as shown in figures, and the low-band gain is increased in comparison with a conventional case. At this time, the low-band resonance frequency of the actuator 16 is set to a value several - several tens times as high as eccentric components. The part indicated by oblique lines in the figure is the increment of the gain. Thus, a high open loop gain is attained, especially, in the low band, and the response to disturbance is improved, and the following-up capacity for eccentricity is improved. |
