47results about How to "Control signal stable" patented technology

An optical head for recording / reproducing signals to / from a high-density multi-layer optical recording medium is provided, which is capable of performing stable recording and reproducing with an aberration in each layer being minimized even when the optical recording medium tilts. The optical head includes a light source (1), an objective lens (7) for focusing light emitted from the light source (1) on an optical recording medium (8), and an objective lens tilting means (13) for correcting an aberration that occurs when the optical recording medium (8) tilts. It is configured so as to vary a tilted amount through which the objective lens tilting means (13) tilts the objective lens according to information concerning a tilt of the optical recording medium (8) and information concerning a substrate thickness of the optical recording medium (8).

A motor drive control device for controlling a rotational speed of a motor includes: a motor driver for rotationally driving a motor; a correction amount calculating section for detecting a rotational speed of an output of the motor in accordance with an alternate current signal outputted from an FG sensor and detecting a rotational position of a photoconductive drum, which is rotated by a rotational drive force of the motor, in accordance with a pulse outputted from an encoder; a speed controller for generating a speed control signal corresponding to a total correction amount, which is a sum of a correction amount calculated in the correction amount calculating section based on a rotational speed of the motor and a correction amount calculated based on a rotational position of the photoconductive drum, and outputting the generated speed control signal to the motor driver.

An optical information apparatus includes a laser which emits a light beam, an objective lens and the like which converge a light beam emitted from the laser on an optical recording medium, spherical aberration correction instrument which is arranged on an optical axis of the light beam which links the laser and the objective lens, and corrects a spherical aberration generated on the optical recording medium. Correction is performed so that outgoing power of the laser changes according to a correction amount by the spherical aberration correction instrument.

The invention relates to a variable delivery hydraulic system. The variable delivery hydraulic system comprises a hydraulic oil tank, a liquid control plunger pump, a hydraulic execution piece, a quantitative reversing valve, a reversing valve control device, an electric proportional pressure reducing valve, and a controller. The liquid control plunger pump sucks hydraulic oil from the hydraulic tank and is driven by an engine, the quantitative reversing valve is connected to the hydraulic execution valve and is used for controlling the hydraulic execution piece, the quantitative reversing valve control device is used for controlling the action of a direction reversing valve. A port B of the liquid control plunger pump is simultaneously connected with port P of the direction switching valve and port P of the electric proportional pressure reducing valve, a port A of the electric proportional pressure reducing valve is connected with the hydraulic oil tank through a speed adjusting valve, the port A of the electric proportional pressure reducing valve is connected with a port X of the liquid control plunger pump, the electrically controlled end of the electric proportional pressurereducing valve is connected with the controller, and the controller outputs corresponded electric signals according to the movement range of the reversing valve control device and the rotating speed of the engine after detecting the movement range of the reversing valve control device through a sensing device and obtaining a rotation parameter of the engine so as to enable the electric proportional pressure reducing valve to generate a corresponding pressure difference value. The variable hydraulic system has the advantages that the performance is stable and excellent, the cost low, and the energy-saving effect is good.