Using as an actuator a stepper motor (11,12) operated in a position-sensed closed loop mode via an electronic commutator by position and anomaly corrected motion control signals provided by a programmable logic array (14) and by a micro-processor (24), provides a precision power positioner. The correct enabling of the motor coils, based on position sensing of the motor phase, using electronic commutation for the stepper motor, transforms the problem of enabling coil selection to the programmable logic array, which by its logic provides a simplified operating control as a function of present armature (12) position feedback (21), and by a micro-processor corrects for anomalies such as temperature rise, square-law, and phase increase as a function of position desired and present armature position feedback signals (22, 23), and thus provides high positional accuracy, high speed and force (torque) control independent of the motor cardinal step positions. A standard 3-phase magnetic resistor sensor (13) is used both to sense the motor phase and to feed back the motor position to the micro-processor for calculation of corrections; actual control of the stepper motor is communicated as a single amplitude modulated control signal.

Electromagnetic actuator system

An optical disk storage access method using a fine and coarse actuators for positioning a light spot to an intended track on the disk, wherein a pulse is generated each time the light spot has traversed a track, the pulses are counted to determine the distance from the current spot position to a target track, the fine actuator is activated depending on the measured distance, and the fine and coarse actuators are operated in unison so that the light spot is positioned to the target track.

Optical disc access method and optical disk storage using coarse and fine actuators

An apparatus for recording data on an M-CAV-formatted optical disk The disk has a plurality of substantially concentric tracks grouped into a plurality of zones arranged in a radial direction of the disk Each of the zones is divided into the same number of sectors, each used as a unit area, and has a different assigned frequency at which to read read data from the sectors Header information is recorded in the start region of each sector and identifies the sector Provided next to the start region is a data field in which data is to be recorded The apparatus is designed to record data in the data field by using a master clock signal having a specific frequency assigned to the zone including that data field The apparatus has a master clock setting circuit for setting the frequency assigned to any zone to which the zone will be switched from the zone in which data is being recorded When the zone is switched to that zone, the gain of the master clock setting circuit is increased temporarily, thereby switching the frequency of the master clock signal within a short time

Optical disk apparatus

An autofocusing control system makes a position of focusing spot (Si) follow for itself a displacement of an information medium (5). In the autofocusing control system, a single mode semiconductor laser (1) is excited in a multi oscillation mode by returning part of a reflected light beam from the information medium, and a focusing lens (20) having chromatic aberration is used which focuses a laser beam from the semiconductor laser onto a different position along the optical axis of the lens in association with a different laser wavelength.

Autofocusing control system

Apparatus is provided for mechanically actuating a valve stem in response to signals generated by an electronic control. A signal means and a sensor means send signals to the electronic control in response to a desired valve stem position and a sensed valve stem position, respectively. The electronic control formulates an error signal if the sensed position is not the desired position. A motor receives a control signal in response to the error signal and drives a linkage for moving the valve stem to the desired position.

Electronic valve actuator

A beam access apparatus for an optical disc system. The apparatus includes a lens position detector for generating a lens position signal indicating a position of the objective lens in a radial direction of the disc with respect to the optical head which is movable relative to the disc. The apparatus is operated in a head access mode in which the optical head is moved in the radial direction of the disc and the objective lens is caused to follow the movement of the optical head such that the objective lens is positioned at a predetermined location with respect to the optical head. The apparatus is also operable in a lens access mode wherein the objective lens is moved in the radial direction and the optical head is caused to follow the objective lens such that the objective lens is located at a predetermined position with respect to the optical head.

Beam access apparatus for optical disc system

A system for controllably driving a motor to place a movable element at a position indicated by a command signal from an external source produces, in response to a phase staggered incremental position signal pair, one and the other of two position pulse sequences at a time depending on an instantaneous angular velocity of the motor. Responsive to the command signal and the position pulses, a mode signal is produced to indicate a position control mode while a position error is within a predetermined range and otherwise a velocity control mode. Likewise, a signal is produced that represents at least one reference angular velocity and the position error during the respective modes. Responsive to the position pulses alone, gate pulses are produced either with two different pulse widths depending on the modes or with a single pulse width. During presence of each gate pulse and dependent on the sense of the instantaneous angular velocity indicated by the position pulses, a digital algebraic adder circuit calculates an algebraic sum of the reference angular velocity or the position error and a reference feedback value, which may either be memorized in the system or supplied from the source and may take two digital values depending on the modes. A digital signal representative of the sums and either the reference angular velocity or the position error during presence and absence, respectively, of the gate pulses is converted to an analog signal, which is smoothed and amplified to provide a motor drive signal.

Position control system comprising a digital algebraic adder circuit

La presente invention concerne un dispositif de commande de position. Un moteur 16 est commande en position en reponse a une paire de signaux de position incrementiels decales en phase 24, 25. En reponse a un signal d'ordre et aux impulsions de position, un signal de mode est produit pour indiquer un mode de commande de position quand l'erreur de position se trouve dans une gamme predeterminee ou pour indiquer dans les autres cas un mode de commande de vitesse. Un circuit d'additionneur algebrique numerique 38 calcule la somme algebrique d'une vitesse angulaire de reference ou d'une valeur d'erreur de position et d'une valeur de reaction de reference, qui peut etre memorisee dans un registre 45. Application aux imprimantes rapides a percussion.

Shigeru Shimonou

Papers

Beam access apparatus for optical disc system

Position control system comprising a digital algebraic adder circuit

Dispositif de commande de position

Einrichtung zur positionssteuerung