315results about "Automatic controllers" patented technology

The present invention provides an irrigation control system in which a device (irrigation scheduler) automatically modifies irrigation schedules of installed irrigation controllers to affect irrigating of the landscape based on the water requirements of the landscape plants and comprises: providing an irrigation controller programmed to execute irrigations on watering days by closing an electrical circuit connecting the controller and at least one irrigation valve; providing an irrigation scheduler programmed to execute irrigations on substantially equivalent watering days as the irrigation controller; and the irrigation scheduler selectively interrupting the electrical circuit to control the execution of irrigations on watering days. Preferably the microprocessor uses either an ETo value or weather data used in calculating the ETo value to at least partially derive the improved irrigation schedule.

An irrigation scheduler modifies output of a preprogrammed irrigation schedule of an installed irrigation controller to at least partially improve irrigation of the corresponding landscape. Preferred embodiments accomplish this task using a microprocessor programmed to: (a) derive a first set of information from the output of an irrigation controller used to control an operation of an irrigation valve; (b) receive a second set of information comprising at least one of an environmental factor and a meteorological factor; and (c) use the first set of information and the second set of information to interfere with reception of the output by the valve.

The invention is a system and method for managing a plurality of areas of interest of a golf course. The system comprises a plurality of subsurface aeration subsystems and a programmable master control module. Each subsystem provides to a specific area at least one of air under pressure and a partial vacuum. In each area of interest, a local control module is responsive to a directive and to a datum (environmental or operational parameter). The local control module is configured to operate the subsystem and is in communication with the programmable master control module. The programmable master control module receives from the local control modules area information representing a status of the respective specific area to which the local control module is dedicated, and in response to the area information and to a command, the programmable master control module issues a directive to the local control module to operate the subsurface aeration subsystem.

The invention discloses a closed loop planar linear motor which includes a stationary stator (or platen) of arbitrary extent, and a moving forcer which is a single rigid body that can move over the planar stator surface on an air bearing with high speed and high precision in two orthogonal translational directions and a small rotation (or combinations thereof). An important distinguishing feature is a monolithic position and orientation sensor based on alternating current (AC) magnetic techniques which is an integral part of the forcer and occupies otherwise unused space in the forcer body. Also incorporated within the forcer is a special electronic processing element which converts weak AC signals from the sensor into usable high precision position and orientation information relative to the stator surface. A unique controller which is part of the closed-loop linear motor acts to combine information from the AC magnetic sensor with input from a user to provide precise, high-performance closed-loop control of the forcer, thereby enabling the forcer to be positioned with sub-micrometer precision and oriented with sub-millidegree precision on the stator surface. Additionally, owing to its closed-loop nature, the forcer can maintain its position and orientation even in the presence of disturbance forces and torques, and can emulate the operation of a mechanical spring and damper.

By applying time-frequency analysis to a given standard iterative learning control or ILC an adaptive filter for the learned feed-forward loop is designed. This time varying filter varies according to the momentary frequency content of the error signal and allows to discriminate between areas of deterministic and stochastic error. Its application results in selective application of ILC to those intervals where error signals of high level are concentrated and allows application of a single ILC acquisition to different setpoint trajectories. The adaptive filter finds particular use in lithographic scanning systems where it is used for varying scan length.

Methods and devices are provided to automatically determine plant water requirements and adjust irrigation in order to make efficient use of water. In one implementation, an irrigation control unit comprises at least one input adapted to be coupled to and receive signals from a rainfall sensor and a temperature sensor, the signals corresponding to current values of an amount of rainfall and temperature. The unit also includes a memory storing historical values of a plurality of variables and a processor coupled to the at least one input and the memory. The processor is adapted to determine plant water requirements at least in part using the historical values of the plurality of variables and the current values of the temperature and the amount of rainfall.

An irrigation control system for land comprising: (a) at least one meter to measure one or more wheather conditions in a first area; (b) at least one monitor to (i) examine rainfall data derived from a radar scanning at least the first area according to predetermined criteria and (ii) to extract data which is representative of the scanned rainfall in a sub-area of the first area; (c) a store to store the extracted data; and (d) a controller connected directly or indirectly to the meter and the monitor and to the store, to calculate a moisture content value for the sub-area and a predetermined moisture content value for the sub-area, and to regulate the irrigation in a sub-area.

The present invention provides systems and methods in which a microprocessor (220) is programmed to calculate an accumulated watering need for an irrigation zone of station (400)and control irrigation to the zone or station (400) using an automatically varied cycle amount that falls between a user controllable maximum threshold and a user controllable minimum threshold. The cycle amount is preferably at least partly derived from ETo data. The minimum threshold may vary during a period of 12 consecutive months, may vary as a function of time of year, as a function of crop maturity or as a function of any other suitable factor where it would be advantageous to set a minimum threshold. The cycle amount may equal the accumulated ETo value(s) or may equal the maximum threshold value. Furthermore, the microprocessor (220) may be programmed to control the irrigation to the zone or station (400) using an automatically varied day schedule.

The present invention relates to a magnetic suspension reaction flywheel open-loop high-accuracy unbalanced vibration control system. It includes the following several portions: displacement sensor, displacement signal interface circuit, rotating speed detection device, magnetic bearing controller, magnetic bearing power amplification drive circuit and flywheel position identification device. The magnetic bearing controller includes axial bearing controller and radial bearing controller, the radial bearing controller is formed from two portions of stabilization controller and unbalanced vibration controller, in which the unbalanced vibration controller can be used for making compensation for displacement feedback of stabilization controller.

Approaches for managing and maintaining a state of charge of an energy storage device by adjusting (biasing) responses to electrical grid operator commands to perform ancillary services are disclosed. In embodiments, methods and systems regulate a set point regulation in an energy system. In an embodiment, a method determines when the set point needs to be changed, calculates a new set point, and moves the output of the system from an old set point to the new set point at a defined ramp rate. The method then incorporates, as part of a set point algorithm, the capability to restore the energy storage device to a desirable state of charge (SOC). Embodiments implement Dynamic Bias, SOC and Signal Bias Range Maintaining, Operational Limits, and Fixed Signal Bias algorithms and perform Intelligent Algorithm Selection to manage and maintain the SOC of an energy storage device by biasing responses to grid operator commands.

Disclosed a high speed magnetic levitation flywheel stability control system, comprises a displacement sensor, a displacement signal interface circuit, a rotary speed detect circuit, a magnetic bearing controller, and a magnetic bearing power amplifying drive circuit. Wherein, the magnetic bearing controller comprises a axial magnetic bearing controller and a radial magnetic bearing controller, while the radial one is formed by decentralized PID control module and a cross feedback control module whose outputs are connected by the feedback method in cross and parallel. Said invention utilizes the cross feedback control formed by forward whirling motion filter and backward whirling motion filter based on the decentralized PID control; it reaches the phase lead compensation to the forward and backward whirling motion by using the difference of their frequency and whirling motion directions, their variation rule of rotary speed, and the signal of rotary speed of flywheel. So the breakdown speed of flywheel is improved while the stable operation of magnetic levitation flywheel in whole rising and falling process is confirmed too.

An irrigation system includes a control arrangement which receives field information relating to an area to be irrigated and source information relating to one or more water sources which supply water to the irrigation system. The control arrangement optimizes an irrigation plan based on the field information and source information and then controls one or more irrigators in accordance with the plan. The control arrangement may pulse valves positioned on the irrigator on and off in order to control the amount of water applied to the land by individual outlets on the irrigator. Latching valves may be used.

A method and device are disclosed for controlling a polyphase motor having a plurality of windings. The device includes a memory device having stored therein data representing a predetermined driving profile, and driver circuit for driving the windings of the polyphase motor based upon the data provided by the memory unit. A feedback control loop is included having an input connected to a selected winding of the polyphase motor and providing an address signal to the memory device that is based upon a current level of the selected winding at around the time the back electromotive force (bemf) signal corresponding thereto crosses a zero reference, for controlling current provided to the windings by the driver circuit so that, for each winding, the current provided thereto is substantially in phase with a back electromotive force (emf) signal corresponding to the winding.

A positioning device is provided. The positioning device includes a movable platform and a monolithic base. Struts are attached to both the movable platform and the monolithic base. The monolithic base moves each of the attached struts to cause the movable platform to move.

Irrigation systems, moisture sensors and related methods having a sensor imbedded in the ground to sense moisture and help control watering. The sensor is responsive to capacitance changes from ground moisture variations. The sensor uses spaced insulated electrodes which are mounted within a granular filled chamber within a water-permeable shell. The sensor is mounted as part of a ground unit that also includes a high frequency driver that excites the sensor. The ground unit further has a detector circuit which produces a moisture indicating signal based on the capacitance which varies with ground moisture. Also disclosed are controllers that electrically isolate the ground units so that reliable moisture signals can be obtained and used to control irrigation. The controllers can be configured to provide multiple zone operation using a shared controller having shared or independent moisture adjusters.