4775 results about "Servo control" patented technology

An optical data storage and retrieval system uses a flying head. The flying head is supported on a moving media having information stored in a plurality of stored data locations thereon. Information is stored in each of the plurality of media locations as physical structures capable of modulating the polarization state of incident light into one of two output polarization states. The flying head includes an optical processing assembly which directs an incident light beam having a source polarization state onto the moving media, accessing successive data locations. A reflected light beam having the source polarization state of the incident light beam modulated by a respective polarization modifying data location into one of the output polarization states is received by the flying head. The optical processing assembly optically transforms the modulated output polarization state of the reflected light beam into two return light beams having differentially modulated intensity related to the output polarization state of the reflected light beam. The two intensity modulated return light beams are optically coupled to a distal differential detector which outputs digital data representing the stored data information for the subject data location. A preferred embodiment includes optical fibers for coupling the incident and return light beams between the detector and the flying head. The optical assembly of a preferred embodiment includes an optical plate having pre-shaped and dimensioned recesses for automatically locating and aligning multiple optical components comprising the assembly. The flying head may also include a servo-controlled micro machined mirror for directing the incident and reflected light beams to and from the media.

The invention prevents dynamic airway compression during ventilatory support of a patient. The respiratory airflow is determined by measurement or calculation, and a measure of the degree of dynamic airway compression is derived from the determined airflow. This measure is servo-controlled to be zero by increasing expiratory pressure if the measure of the degree of dynamic airway compression is large or increasing, and by reducing expiratory pressure if the measure of the degree of dynamic airway compression is small or zero.

Servo control using ferromagnetic core material and electrical windings is based on monitoring of winding currents and voltages and inference of magnetic flux, a force indication; and magnetic gap, a position indication. Third order nonlinear servo control is split into nested control loops: a fast nonlinear first-order inner loop causing flux to track a target by varying a voltage output; and a slower almost linear second-order outer loop causing magnetic gap to track a target by controlling the flux target of the inner loop. The inner loop uses efficient switching regulation, preferably based on controlled feedback instabilities, to control voltage output. The outer loop achieves damping and accurate convergence using proportional, time-integral, and time-derivative gain terms. The time-integral feedback may be based on measured and target solenoid drive currents, adjusting the magnetic gap for force balance at the target current. Incorporation of permanent magnet material permits the target current to be zero, achieving levitation with low power, including for a monorail deriving propulsion from the levitation magnets. Linear magnetic approximations lead to the simplest controller, but nonlinear analog computation in the log domain yields a better controller with relatively few parts. When servo-controlled solenoids provide actuation of a pump piston and valves, electronic LC resonance measurements determine liquid volume and gas bubble volume.

The invention is a ventilator whose servo-controller adjusts the degree of support by adjusting the profile of the pressure waveform as well as the pressure modulation amplitude. As the servo-controller increases the degree of support by increasing the pressure modulation amplitude, it also generates a progressively more square, and therefore efficient, pressure waveform; when the servo-controller decreases the degree of support by decreasing the pressure modulation amplitude, it also generates a progressively more smooth and therefore comfortable pressure waveform.