4532 results about "Feedback control" patented technology

In a lithographic apparatus, a localized area of the substrate surface under a projection system is immersed in liquid. The height of a liquid supply system above the surface of the substrate can be varied using actuators. A control system uses feedforward or feedback control with input of the surface height of the substrate to maintain the liquid supply system at a predetermined height above the surface of the substrate.

An electrosurgical generator which provides a constant power output particularly suited for cutting arc formation at an active electrode which exhibits a dynamic active surface area of varying geometry. Essentially constant power-based control is achieved through the utilization of a d.c. link voltage the level of which functions to establish the amplitude of the output of an RF resonant inverter. A dual loop feedback control is described wherein output power based control signals are slowly introduced at low gain, while link voltage based controls are comparatively rapidly applied. Enhanced development of a controlling d.c. link voltage is achieved through the utilization of an input network incorporating a power factor correction stage.

The present invention relates to a method and a device to monitor and control the Selective Laser Powder Processing. A Selective Laser Powder Processing device comprising a feedback controller to improve the stability of the Selective Laser Powder Processing process is presented. A signal reflecting a geometric quantity of the melt zone is used in the feedback controller to adjust the scanning parameters (e.g. laser power, laser spot size, scanning velocity, . . . ) of the laser beam (4) in order to maintain the geometric quantity of the melt zone at a constant level. The signal reflecting the geometric quantity of the melt zone can also be displayed in order to monitor the Selective Laser Powder Processing process. The present invention allows for the production of three-dimensional objects from powder material and improves the state of the art by compensating variations of the border conditions (e.g. local heat conduction rate) by a feedback control system based on a geometric quantity of the melt zone resulting in e.g. a lower amount of dross material when overhang planes are scanned.

Scanning Laser Epitaxy (SLE) is a layer-by-layer additive manufacturing process that allows for the fabrication of three-dimensional objects with specified microstructure through the controlled melting and re-solidification of a metal powders placed atop a base substrate. SLE can be used to repair single crystal (SX) turbine airfoils, for example, as well as the manufacture functionally graded turbine components. The SLE process is capable of creating equiaxed, directionally solidified, and SX structures. Real-time feedback control schemes based upon an offline model can be used both to create specified defect free microstructures and to improve the repeatability of the process. Control schemes can be used based upon temperature data feedback provided at high frame rate by a thermal imaging camera as well as a melt-pool viewing video microscope. A real-time control scheme can deliver the capability of creating engine ready net shape turbine components from raw powder material.

A device for generating droplets includes a substrate comprising a reservoir site configured to hold a liquid and including a first electrode, a droplet creation site including a second electrode, and droplet separation site disposed between the reservoir site and the droplet creation site and containing an electrode. The device includes control circuitry operatively coupled to the first, second, and third electrodes. The control circuitry is configured to measure the fluid volume on the electrodes and independently adjust an applied voltage to increase/decrease the quantity of fluid. The device can move fluid onto the creation site or back onto to the reservoir site. When the fluid volume is at the desired value or range, a driving voltage is delivered to the first and second electrodes to form a new droplet. The device may generate droplets having a uniform or user-defined size smaller than the electrode.

A radio frequency power amplifier includes a feedback control system coupled to an input signal and a first feedback signal and configured to provide an output; a controlled supply configured to provide power that is controlled in accordance with a signal; and a radio frequency gain stage powered from the controlled supply, driven by the output from the feedback control system, and configured to provide an output signal at the radio frequency to a resonant load, where the first feedback signal corresponds to the output signal. Some embodiments include a sequencer in the feedback control system and others utilize an additional feedback loop to control the power provided by the controlled supply.

A battery charging device, method and system are disclosed for wirelessly charging a battery. A transmitter can transmit an RF wireless power signal to a battery charging device, and a receiver within the battery charging device can receive the RF wireless power signal. The battery charging device can thereafter transfer the received RF wireless power signal to a battery receiving portion to charge the battery. In an embodiment, the RF wireless power signal is transferred at a frequency of about 13.56 MHz to overcome wave shadowing. A battery recharging feedback control circuit can optionally be applied in combination with the battery charging device and can monitor a power quantity of the RF wireless power signal.

Systems and methods for beamforming in radio frequency identification (RFID) applications are disclosed. A beamforming system uses a distributed architecture and techniques for antenna beamforming using a feedback control loop to direct radio frequency (RF) energy onto a specific region, referred to as an interrogation zone, which includes a calibration node where one or more RFID tags may be located. The distributed architecture of the beamforming system is resistant to fading and shadowing effects, providing accurate RFID reader operation even in environments with multi-path reflections or environmental changes, such as people moving around or changes in the location of equipment.

A system for radio frequency identification of a tag in an interrogation zone, includes a calibration node disposed in the interrogation zone to measure a signal strength of radio frequency identification signals from a beamforming system and provide signal data in accordance with the signal strength. A reader node is configured to receive the signal data and adjust the radio frequency identification signals generated by the beamforming system based upon the signal data. At least one of the calibration node, the reader node and the beamforming system is a configurable monitoring system. The calibration node, the reader node, and the beamforming system are coupled in a feedback control loop. The beamforming system includes a plurality of beamforming nodes. A signal of at least one beamforming node is optimized in accordance with the feedback control loop.

Plasma distribution is controlled in a plasma reactor by controlling the phase differences between different RF coil antennas, in accordance with a desired or user-selected phase difference, by a phase-lock feedback control loop.

A system and method of assisting a driver of a vehicle by providing driver and vehicle feedback control signals is disclosed. The system and method includes receiving location data of the vehicle from a GPS unit, receiving the location data of the vehicle and retrieving navigation characteristics relevant to the location data using a processing circuit, generating a most probable future path for the vehicle and determining a location of at least one navigation characteristic with respect to the most probable future path and the vehicle, generating vehicle data at least one vehicle sensor, and transmitting a control signal to a vehicle control area network to warn the driver of an upcoming navigation characteristic on the most probable path.

A phase locked loop includes at least one control circuit, where a voltage-controlled oscillator provides an output frequency which is arranged to strive to follow an input frequency. The phase locked loop also includes an outer, slow, negative feedback control circuit, having the input frequency as a setpoint, the output frequency as a process value and an outer output signal. The phase locked loop also includes an inner, fast, negative feedback control circuit, having the sum of a reference frequency from a stable oscillator and the outer output signal as a setpoint, the output frequency as the process value and an inner output signal for controlling the voltage controlled oscillator.

An MPC adaptation and tuning technique integrates feedback control performance better than methods commonly used today in MPC type controllers, resulting in an MPC adaptation/tuning technique that performs better than traditional MPC techniques in the presence of process model mismatch. The MPC controller performance is enhanced by adding a controller adaptation/tuning unit to an MPC controller, which adaptation/tuning unit implements an optimization routine to determine the best or most optimal set of controller design and/or tuning parameters to use within the MPC controller during on-line process control in the presence of a specific amount of model mismatch or a range of model mismatch. The adaptation/tuning unit determines one or more MPC controller tuning and design parameters, including for example, an MPC form, penalty factors for either or both of an MPC controller and an observer and a controller model for use in the MPC controller, based on a previously determined process model and either a known or an expected process model mismatch or process model mismatch range. A closed loop adaptation cycle may be implemented by performing an autocorrelation analysis on the prediction error or the control error to determine when significant process model mismatch exists or to determine an increase or a decrease in process model mismatch over time.

A contactless electrical energy transmission system includes a transformer having a primary winding that is coupled to a power source through a primary resonant circuit and a secondary winding that is coupled to a load through a secondary resonant circuit. The primary and secondary resonant circuits are inductively coupled to each other. A primary control circuit detects current changes through the primary resonant circuit to control the switching frequency of a controllable switching device for maintaining a substantially constant energy transfer between the primary winding and secondary winding in response to at least one of a power source voltage change and a load change. As a result, excessive circulating energy of the CEET system is minimized providing a tight regulation of the output voltage over the entire load and input voltage ranges without any feedback connection between the primary side and the secondary side.

Described herein are improved configurations for a wireless lighting power transfer method including providing a source having a source resonator that includes a high-Q source magnetic resonator coupled to a power source, providing a device having a device resonator that includes a high-Q device magnetic resonator, distal from the source resonator, the device including a light emitting part electrically coupled to the device resonator, providing a signaling capability between the source and the device, signaling a state of the device to the source using the signaling capability, and energizing the source to generate an oscillating magnetic field according to the state of the device.

A vertical axis windmill is provided wherein the amount of wind directed to blades in the power producing part of rotation and the mechanical load of multiple generators is controlled by a feedback control to maintain a relatively constant rotational frequency of the shaft of the windmill. In a preferred embodiment, two wind foils extend radially outwardly from the blades to thereby provide a scoop capable of pulling in more air than would normally be received by the blades. The wind foils then direct the wind flow to the power producing part of rotation of the blades for maximum power output, when necessary. The wind foils can close to control the wind flow to the blades. The generating capacity of a plurality of generators is also controlled in response to shaft rotation to maintain substantially constant shaft rotation.

A method of controlling operation of a wireless device configured in a zero intermediate frequency architecture including a DC loop and a gain loop. The method includes processing energy in a wireless medium to generate a corresponding receive signal, monitoring the receive signal via a predetermined measurement window, detecting a changed condition in the channel, holding the gain feedback control loop at a constant gain level, and operating the DC loop in an attempt to search a stable DC value for the receive signal while the gain loop is held constant. A first case is DC saturation, where the gain is held constant until DC is controlled. A second case is clear channel assessment, where a prior stored gain setting is applied to the gain loop after detecting the end of the packet. A third case is preparation for receiving an expected acknowledgement packet after transmitting a packet, where again a prior stored gain setting is applied to the gain loop and DC is searched.

A gas-lift petroleum well and method for producing petroleum products using downhole pressurized gas to provide lift. The gas-lift well having a well casing, a production tubing, a packer, and a gas-lift valve. The well casing extends within a wellbore of the well, and the wellbore extends through oil and gas zones. The production tubing extends within the casing. The tubing having an opening formed therein, which is in fluid communication with an oil zone. The packer is located downhole in the casing and coupled to the tubing. The packer can have an electrically controllable packer valve, which is adapted to control a flow of downhole pressurized gas from one side of the packer to another. The downhole pressurized gas is provided by a gas zone that the wellbore passes through. The downhole gas-lift valve is coupled to the tubing and is adapted to control a flow of downhole pressurized gas into oil in the tubing for lifting the oil. The gas-lift valve can be an electrically controllable valve. The tubing and casing are used as electrical conductors for supplying power and/or communications downhole. The current in the tubing is routed using a ferromagnetic induction choke to create a voltage potential, which provides electrical power to downhole electrical devices. Also, there may be a bypass passageway to route downhole gas to gas-lift valves. There may also be downhole sensors to measure physical quantities (e.g., pressure). Such measurements can be used for feedback control of downhole electrically controllable valves.

An automated electronic video surveillance system enables a high-resolution mega-pixel camera to capture high quality, detailed, magnified images at multiple locations, simultaneously with an overview of the whole scene. A preferred embodiment requiring no moving parts provides full 360-degree continuous viewing with up to 5× all-digital zoom capability. The system performs continuous surveillance and active resolution allocation in the form of a feedback control subsystem that dynamically allocates resources so that important details within a scene receive appropriate scrutiny, while uninteresting areas are imaged at a lower resolution.

An AC-to-DC power converter that is capable of generating a regulated, isolated DC voltage output from a power factor corrected AC voltage input with improved efficiency. The AC-to-DC power converter is a two-stage power converter including a PFC stage connected in series to a power conversion stage. The PFC stage performs power factor correction using a zero current switching technique, and the power conversion stage includes a zero voltage switched half-bridge converter. The power conversion stage includes a transformer for providing the isolated DC voltage output. The AC-to-DC power converter includes a single feedback control loop for transferring error information from the DC voltage output to the PFC stage, thereby obtaining regulation of the DC voltage output.

A pulse-width-modulation control circuit of a switching-mode power converter with a primary-side feedback control is disclosed. The switching-mode power converter includes a transformer, a power switch, a current sensing resistor and the pulse-width-modulation control circuit. The transformer includes a primary-side winding, a secondary-side winding and an auxiliary winding. The pulse-width-modulation control circuit includes a sample and hold circuit, a transconductor circuit, an error amplifier and a pulse-width-modulation generator.

A multivariable feedback control approach to actively dampen magnitude of jerks in a powertrain system using multiple torque-control devices is offered. To manage jerks, a desired axle torque is restricted when a torque reversal occurs. When the vehicle operator or the system executes a command that requires change in direction of torque, the desired axle torque is limited to a low level until the lash estimate has changed accordingly. During this transition time, active damping controls driveline component speeds so that the effect of lash take-up is minimized. After lash take-up occurs, the desired axle torque proceeds without restriction. The invention includes determining a desired axle torque, an output speed of the transmission, and an output speed of a driven wheel of the driveline. One of the devices is controlled based upon a time-rate change in the desired axle torque.

Various devices, systems and methods for providing effective, long term and reliable use of pressure feedback in VADs. Exemplary embodiments are described which provide for direct LV pressure measurement, non-invasive calibration techniques to detect ventricular collapse and recalibrate the feedback mechanism, improved pressure sensor designs with reduced drift, and barometric pressure correction schemes. These devices and methods may be used alone or in combination with each other, and may also be combined with other feedback mechanisms.

The silicon etching apparatus using XeF2 includes: a basic structure composed of a loading chamber tot loading XeF2, an expansion chamber for collecting sublimated XeF2 gas, and an etching chamber for performing an etching process; and a means for injecting nitrogen prior to the etching process to eliminate air moisture in the apparatus and thus preventing the formation of HF. The silicon etching apparatus using XeF2 further includes: an injector having a predefined shape provided in the etching chamber for uniformly injecting the XeF2 gas downward on to surface of a wafer; a feedback controller for feedback controlling the internal pressure of the loading chamber in order to prevent sublimation of the residual XeF2 in the loading chamber; and a weight scale for measuring the weight of XeF2 in the loading chamber.

The invention relates generally to methods of monitoring and controlling the processing of blood and blood samples, particularly the separation of blood and blood samples into its components. In one aspect, the invention relates to optical methods, devices and device components for measuring two-dimensional distributions of transmitted light intensities, scattered light intensities or both from a separation chamber of a density centrifuge. In embodiment, two-dimensional distributions of transmitted light intensities, scattered light intensities or both measured by the methods of the present invention comprise images of a separation chamber or component thereof, such as an optical cell of a separation chamber. In another aspect, the present invention relates to multifunctional monitoring and control systems for blood processing, particularly blood processing via density centrifugation. Feedback control systems are provided wherein two-dimensional distributions of transmitted light intensities, scattered light intensities or both are measured, processed in real time and are used as the basis of output signals for controlling blood processing. In another aspect, optical cells and methods of using optical cells for monitoring and control blood processing are provided.

An apparatus and method for mixing fluids and/or solids in a manner that can be varied from maintaining the integrity of fragile molecular and biological materials in the mixing vessel to homogenizing heavy aggregate material by supplying large amounts of energy. Variation in the manner of mixing is accomplished using an electronic controller to generate signals to control the frequency and amplitude of the motor(s), which drive an unbalanced shaft assembly to produce a linear vibratory motion. The motor may be a stepper motors a linear motor or a DC continuous motor. By placing a sensor on the mixing vessel platform to provide feedback control of the mixing motor, the characteristics of agitation in the fluid or solid can be adjusted to optimize the degree of mixing and produce a high quality mixant.

A method and apparatus is provided for determining an effective thermal mass of a patient. The effective thermal mass is employed to determine a gain factor used in a feedback control system controlling patient temperature. The method begins by inducing hypothermia or hyperthermia in at least a selected portion of the patient with a device having a heat transfer surface. Next, power is transferred between the device and the patient. A change in temperature over time, which arises in the selected portion of the patient, is measured while performing the step of inducing hypothermia or hyperthermia. Finally, an effective thermal mass is calculated based on the measured power and the measured temperature change over time.

Disclosed are devices, arrangements and methods for quantifying the concentration of an analyte present in bodily fluid, including: an assay pad having at least one chemical reagent capable of producing a detectable signal in the form of a reaction spot upon reaction with the analyte; a light source; a detector array; a processor; and a memory in communication with the processor, the memory comprising: (a) at least one value indicative of one or more of: (i) the level of hematocrit contained in the sample; (ii) the volume of the sample applied to the assay pad; or (iii) imperfections present in the reaction spot; and (b) at least one algorithm for calculating the concentration of the analyte contained in the sample.

A haptic feedback control device, such as a handheld remote control or handheld game controller, for controlling a graphical object within a graphical display and for outputting forces to a user. A housing includes a button, wherein the user engages the button with a finger. The button is depressible along a degree of freedom by the user. An actuator applies forces to the user through the button along the degree of freedom. A sensor detects displacement of the button along the degree of freedom when the button is depressed by the user. A process, local to the device, controls the actuator to generate the forces upon the button in the degree of freedom to provide a tactile sensation to the user contacting the button.

This invention relates to opto-electronic systems using semiconductor lasers driven by feedback control circuits that control the laser's optical phase and frequency. Feedback control provides a means for coherent phased laser array operation and reduced phase noise. Systems and methods to coherently combine a multiplicity of lasers driven to provide high power coherent outputs with tailored spectral and wavefront characteristics are disclosed. Systems of improving the phase noise characteristics of one or more semiconductor lasers are further disclosed.