11925 results about "Feedback control" patented technology

A temperature monitoring device and/or method which control the tissue temperature at the end-effector of a therapeutic ultrasonic cutting and coagulating instrument as the tissue is being heated with ultrasonic vibrations from the end-effector. One or more temperature sensors are located at the end-effector, preferably on a clamping member. The temperature sensors measure the temperature of the tissue engaged by the end-effector either directly or indirectly. An alternate method and apparatus provides an electrical tissue impedance measure in combination with an ultrasonic cutting and coagulating instrument to provide active feedback control of an ultrasonic generator.

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.

A video endoscope system includes a reusable control cabinet and an endoscope that is connectable thereto. The endoscope may be used with a single patient and then disposed. The endoscope includes an illumination mechanism, an image sensor, and an elongate shaft having one or more lumens located therein. An articulation joint at the distal end of the endoscope allows the distal end to be oriented by the actuators in the control cabinet or actuators in a control handle of the endoscope. Fluidics, electrical, navigation, image, display and data entry controls are integrated into the system along with other accessories.

A system uses automatic feedback and control to secure a network infrastructure by iterative convergence of the network's security structure to meet a security policy. Following initialization, a security feedback control system of the security management system makes dynamic adjustments to the system using bi-directional services that are controlled via policy decision components, without user intervention.

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.

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

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.