Tracking servo repeated controlling system for high-speed reading for eccentric DVD disk

Abstract

A track-following servo repeat control system of high speed fetching eccentric DVD disc is prepared as converting optical signal of laser read / write to be electric signal by detection conversion module, comparing electric signal with set value to generate track-following error signal, identifying whether eccentric is existed or not by intelligent decision module and carrying out compensation and calibration on track-following error signal by repeat compensation module then outputting compensated- calibrated signal to track-following servo system through universal control module if it is or otherwise directly outputting signal to track-following servo system.

Description

technical field [0001] The invention relates to a servo control system of a DVD disc player, more specifically, to a tracking servo repeat control system for high-speed reading of eccentric DVD discs. It belongs to the field of electronic information technology. Background technique [0002] The equivalent physical model of the DVD drive tracking servo control mechanism can be regarded as a double-car structure. The trolley is connected to the cart through a spring and a damper, and there is a complex coupling relationship between them. Among them, the cart corresponds to the coarse adjustment actuator, which is generally a DC brushless motor, which is mainly used for fast and long-distance tracking. It has a large moving range, but the bandwidth is relatively small, and the corresponding speed is relatively slow. The trolley corresponds to the fine-tuning actuator, which is a voice coil motor and carries the laser reader OPU (optical pick-up). Its main function is short-di...

AI Technical Summary

Problems solved by technology

Therefore, for an eccentric disc with a maximum amplitude of 50 μm, the optical head deflection of the laser reader cannot exceed 0.022 μm, that is, the ratio of tracking error to disc eccentricity cannot be greater than However, in order to meet this requirement, the standard characteristics of the ideal open-loop tracking servo determine that the rotation frequency of the disc cannot be greater than 23.1 Hz. For a speed higher than 23.1 Hz, the ratio of the tracking error to the eccentricity of the disc will be greater than K 0 , DVD tracking servo system will not meet the requirements

However, the speed of modern DVD has reached 48 times, and the speed of the spindle motor is 9600 rpm, about 160Hz, so the system cannot suppress such a high-frequency run-out disturbance signal, so it cannot read eccentric discs at high speed

[0004] After searching the literature of the prior art, it is found that the Chinese invention patent (application number 01110490.2) proposes an optical drive tracking servo system and method, which is used to control the optical read-write head to track the data track, including: Sensing device, control device, decision-making device and power device are only suitable for discs without eccentricity, and cannot solve the problem of sinusoidal cycle run-out (Run-Out) caused by disc eccentricity, let alone at a speed exceeding 23.1Hz Read eccentric DVD discs at high speed

Images