218 results about "Compensation strategy" patented technology

A spindle thermal distortion compensation method for a precision horizontal machining center comprises the steps as follows: a spindle model of a machine tool is simplified structurally; an ANSYS (finite element analysis software)-Workbench is utilized to perform mesh generation on a spindle entity model that is simplified, so as to obtain a spindle finite element model; and boundary conditions are calculated by combining with the practical spindle rotational speed, the environmental temperature, the coolant velocity, the flow rate, the inlet and outlet oil temperature and the like, and configuration is performed. Thermodynamics analysis and statics analysis are carried out in the ANSYS-Workbench to obtain more accurate spindle temperature field distribution and thermal deformation. Based on a finite element emulation result, the spindle temperatures in different positions and the spindle thermal deformations are analyzed at different rotational speeds by utilizing the Spearman rank correlation analysis, and spindle thermal key points are found out, so that references are provided to spindle thermal error tests and thermal error compensation. Finally, a thermal error compensation model is built up by utilizing a least squares method according to the key point temperature of the spindle and the thermal errors in the practical tests. Based on the thermal error compensation model, the spindle thermal error compensation is carried out by combining with thermal error compensation strategies of a numerical control system of the machine tool.

The invention provides an intelligent reactive compensation comprehensive control device, wherein a judging process of a judging module in a central processing unit is as follows: 1, judging whether to switch on or switch off according to reactive power or power factor of an electric grid; 2, judging whether voltages in three phases are all in a range of allowing the switching on or the switchingoff; 3, calculating a vacancy value or an excess value of total reactive power, and selecting a total compensation capacitor group; 4, calculating the vacancy value or the excess value of the reactive power of each phase, and selecting an individual compensation capacitor group; 5, judging whether the capacitor group is in blocking state; and 6, outputting switching on or switching off instructions to a switching outlet driving unit of the compensation capacitor. The control device uses the reactive power or the power factor of the electric grid as criterion for controlling the switching on or the switching off of the capacitor groups, uses the voltage as a constraint condition, and uses the vacancy or the excess of the reactive power to preferentially select a reactive power compensationpolicy and the capacitor groups to be switched, so that the power factor of the electric grid can be effectively improved, losses of the electric grid can be reduced, and voltage quality of the electric grid is ensured.

An SVC compensation strategy optimization method, comprising: calculating a weak voltage node in a fault state based on risk measure; calculating the weak voltage node in a normal state based on a static stability margin; and determining an optimal SVC distribution point and calculating the optimal configuration of SVC capacity. The SVC compensation strategy optimization method overcomes the defects in the prior art, such as low reliability, low optimization precision, poor applicability, etc., and has the advantages of high reliability, high optimization precision, and good applicability.

The invention discloses a short circuit fault tolerant control method for a five-phase fault tolerant permanent magnet motor. The method comprises the following steps: establishing a five-phase fault tolerant permanent magnet motor model; compensating a short circuit fault phase normal torque loss by using non-fault phase current by directly adopting a compensation strategy of an open fault; compensating the fluctuated magnetic motive force caused by the short circuit fault phase current by using non-fault phase current, so that the synthetic magnetic motive force is zero; eliminating torque ripple caused by the short circuit current; synthesizing the vectors of the compensating current of the steps 2 to 3 to obtain the short circuit fault tolerant current; performing control and simulation on Maxwell short circuit fault tolerant. According to the short circuit fault tolerant control method for the five-phase fault tolerant permanent magnet motor, one-phase short circuit fault tolerant control is performed on the motor according to the specific situation of the no-load counter electromotive force of the motor, so that the fault is equivalent to the output torque in a normal operating state; the torque ripple is reduced; the operation of the five-phase fault tolerant permanent magnet motor with a short circuit fault is realized.

A method of steady-state free precession MR imaging is provided that includes the steps of: (a) providing a balanced steady-state free precession imaging sequence that includes a plurality of phase encoding steps, wherein each phase encoding step comprises a phase encoding gradient and a slice selection gradient; and (b) acquiring imaging data by performing the plurality of phase encoding steps in sequence, wherein the imaging data is acquired is compensated for one or more effects due to eddy-currents, flow, or motion related artefacts due to the implementation of one or more artefact compensation strategies that consist of (i) “pairing” of consecutive phase encoding steps and of (ii) “through slice equilibration” of eddy-current and motion or flow related signal oscillations.

A shipborne camera shooting stabilized platform control method with an active disturbance rejection control technology adopted includes the following steps that (1) a discrete time state-space model of a shipborne camera shooting stabilized platform control system is built; (2) a tracking differentiator is designed, and the rotation angle of a camera shooting stabilized platform can track the reference angle as soon as possible without overshoot; (3) an extended state observer is designed to estimate the rotation angle, the rotation angular speed, the rotation angular acceleration and the total disturbance of the camera shooting stabilized platform; (4) tracking errors of the angle, the angular speed and the angular acceleration are obtained according to the output of the tracking differentiator and the output of the extended state observer, and then a nonlinear control rule and a disturbance compensation strategy are designed according to the error information. By means of the shipborne camera shooting stabilized platform control method, the tracking accuracy and rapidity of the camera shooting stabilized platform are guaranteed, and the high disturbance rejection capacity is provided.

The invention discloses a method for starting a compressor of a variable frequency air conditioner and compensating low-frequency torque. The method for starting the compressor of the variable frequency air conditioner and compensating the low-frequency torque comprises the two steps of starting the compressor of the variable frequency air conditioner and compensating the low-frequency torque. After the compressor of the variable frequency air conditioner is started, the compressor starts operating in an open-loop state. At the time of starting of the compressor, an initial speed with a certain step size and an initial starting current with a certain step size are provided until the compressor is started. A compensation strategy is determined according to the range of variance difference values which are worked out after the compressor is successfully started. According to the method for starting the compressor of the variable frequency air conditioner and compensating the low-frequency torque, successful starting of the compressor is achieved, switching between an open-loop strategy and a closed-loop strategy is soft switching so that impact of the large starting voltage and the large starting current on a controlling chip is avoided; the service life of the controlling chip is prolonged; the success rate of starting is larger than 99.99%; the starting time is controlled to be around 500ms. The method for starting the compressor of the variable frequency air conditioner and compensating the low-frequency torque avoids the limitation of feed-forward table look-up compensation control, and is applicable to various compressors and capable of achieving 5-40Hz long stable operation of the variable frequency air conditioner.

The invention discloses a steer-by-wire double-motor system based on driver behavior identification and a yaw stability compensation strategy thereof. The system comprises an acquisition unit, a central controller, a steering wheel assembly and a front wheel steering assembly; the compensation strategy of the steer-by-wire double-motor system is that: a predicted steering-wheel steering angle is obtained by driver behavior identification and a steering-wheel steering angle measured by a steering-wheel steering angle sensor, and is transferred to the central controller, a yaw angular speed gainand a lateral acceleration factor are integrated to obtain an ideal transmission ratio, and a relationship between the steering-wheel steering angle and an ideal input steering angle of a steering-angle motor is obtained and transferred to a steering angle motor controller so as to carry out open-loop control on the steering angle motor; then an ideal front wheel steering angle is obtained according to the steering-wheel steering angle and the ideal transmission ratio, an ideal yaw angular speed is obtained, a compensation torque of the system is obtained by a robust controller, and the compensation torque is transferred to a torque motor controller by a compensation control strategy so as to ensure rapid response performance of the system and driving stability in the driving process.

The invention discloses a method for restraining subsynchronous oscillation caused by grid connection of a draught fan based on SVG. The method includes firstly measuring frequency of subsynchronous oscillating current of a power grid, performing FFT analysis, and thereby obtaining all subsynchronous oscillating frequencies. The difference between the working frequency and the subsynchronous current oscillating frequency of the system is set as the central frequency of a band-pass filter for designing the BPF (Band-Pass Filter). The SVG current loop control design namely includes decoupling under a DQ rotating coordinate system, and enabling subsynchronous oscillating current signals obtained through detecting under the DQ rotating coordinate system to pass through the filter to obtain reactive current commands. The compensation strategy for compensating subsynchronous oscillation caused by grid connection of wind power in a distributed manner namely includes: through the design of distributed SVG compensation points, increasing capacity of the SVG for compensating subsynchronous oscillating current of the power grid, and restraining the problem of subsynchronous oscillation caused by grid connection of wind power at different nodes in a targeted manner.

A method of steady-state free precession MR imaging is provided that includes the steps of: (a) providing a balanced steady-state free precession imaging sequence that includes a plurality of phase encoding steps, wherein each phase encoding step comprises a phase encoding gradient and a slice selection gradient; and (b) acquiring imaging data by performing the plurality of phase encoding steps in sequence, wherein the imaging data is acquired is compensated for one or more effects due to eddy-currents, flow, or motion related artefacts due to the implementation of one or more artefact compensation strategies that consist of (i) “pairing” of consecutive phase encoding steps and of (ii) “through slice equilibration” of eddy-current and motion or flow related signal oscillations.

The present invention discloses a self-calibration method for an electric power steering system, which can self-calibrate the sensors to a normalized state to prevent from signal distortion, whereby to maintain stable steering sense of the driver and promote robustness and performance of the EPS system. The self-calibration method includes a signal offset compensation tactic and a zero-point signal self-calibration tactic. The present invention determines whether to undertake self-calibration according to judgement tactics, including a sensor power supply judgement tactic, a sensor correctness judgement tactic, and a self-calibration triggering condition. The self-calibration method can increase the correctness of sensors, maintain the original steering-assisting function and promote robustness of the EPS system.

An internal combustion engine (10) has a control system (24) for processing various data to develop data for control of various aspects of engine operation, including controlling a device, such as an EGR valve (22) or turbocharger (16). A transient compensation strategy develops a multiplier data value for transient compensation of a control data value for controlling the device by multiplying that control data value by that multiplier data value. The transient compensation strategy comprises a map (34, 40) containing data values for the multiplier, each of which is correlated with both a particular data value for engine speed within a range of data values for engine speed (N) and a particular data value for accelerator pedal rate (APS—d) within a range of data values for accelerator pedal rate. The strategy selects one of the multiplier data values from the map on the basis of a data value for engine speed and of a data value for accelerator pedal rate and then multiplies the control data value for controlling the device by the one selected multiplier data value.

The invention relates to control strategies of a three-phase inverter, and discloses a dead-zone compensation method of the three-phase inverter. The dead-zone compensation method of the three-phase inverter can effectively improve waveform distortion caused by a dead zone and reduce THD. The dead-zone compensation method is an off-line dead-zone compensation method and mainly comprises two parts including (1) accurate judgment on the inductive current polarity and (2) dead-zone compensation strategies under a, b and c coordinates according to a three-phase system. The accurate judgment on the inductive current fundamental wave polarity can further be divided into sampled inductive current polarity detection, electric current measurement circuit delay calculation and fundamental wave delay estimation caused by the dead zone, the inductive current fundamental wave polarity can be accurately obtained through the three steps, then the compensation strategies under the a, b and c coordinate system are adopted, therefore, extra delay caused by using a low pass filter is avoided, and compensation is turned to be simple and practical.

The invention provides an image brightness compensation method and device, and a terminal device. An image sensor provided in advance comprises a light-sensing pixel array and a light filter disposed on the light-sensing pixel array. The light filter comprises a light-filtering unit array. Each light-filtering unit covers multiple light-sensing pixels and forms a combined pixel. The method comprises steps of: detecting whether combined pixels at corners reach preset brightness when a combined image is generated by adding the outputs of multiple light-sensing pixels belonging to one combined pixel to acquire a pixel value; if yes, performing depressed compensation on the brightness of other combined pixels according to a preset compensation strategy and with reference to the pixel values of the combined pixels at the corners. The method and device achieve brightness depressed compensation on the pixels from a center to the corners so that the brightness of an entire image is uniform and the noise of the entire image is controlled to a certain extent. Thus, image quality is increased and burden of later image de-nosing is decreased.

A method for determining a die profile for forming a metal part having a desired shape. The method includes the steps of providing a nominal die profile, determining a springback profile based on the nominal die profile and employing a compensation strategy to determine the die profile based on the nominal die profile and the springback profile. There are disclosed five (5) compensation strategies: (1) a reversed die-normal technique; (2) a reversed radial rotation technique; (3) a reversed resultant vector technique; (4) a reversed path technique; and (5) a mirror image of resultant vector technique. Associated methods of making a die based on the die profile determined above and making a metal part under a set of forming conditions from the die are also disclosed.

The invention provides a realization method for functions of an adaptive load type distribution transformer. The realization method comprises the following steps of setting adaptive load type distribution transformer motion constant values which include a three-phase load unbalance adjusting constant value, a phase-splitting reactive compensation constant value, a load capacitance-modulating current constant value and a load voltage-modulating voltage constant value, and according to the set adaptive load type distribution transformer motion constant values, performing three-phase load balance control, phase-splitting reactive compensation control, rated capacity operation model adjusting control and voltage tap shift adjusting control. The realization method fulfills an aim of adaptive loads by scientifically setting the load capacitance-modulating motion constant value and combining the three-phase load unbalance adjustment and phase-splitting reactive compensation strategy, helps to effectively reduce operation loss of the distribution transformer and low-voltage network wire loss, improve the economic operation level of the power distribution area and guarantee power supply quality to users.

The invention discloses a method and a system for live broadcast of peer-to-peer (P2P) streaming media. The method comprises the following steps that: the state of a data buffer zone of a live streaming media is monitored; when a data safe zone is not fully filled by the data of the data buffer zone, a client node preferably requests the corresponding live broadcast streaming media data to a compensation server; and when the data safe zone is fully filled by the data of the data buffer zone, the client node requests the corresponding live broadcast streaming media data to an upper node according to a mark of the upper node. In the method and the system, the user node selects the nodes with good network transmission attribute according to a node marking strategy to form a node queue so as to meet a data transmission requirement under a high-definition code stream condition; and through a compensation strategy of the safe zone, safety precaution of data buffering capacity is realized, data intelligent functionalized compensation is actualized and P2P high-definition streaming media live broadcast smooth play is realized.

The invention discloses a point potential balance control method in a three-level NPC inverter. The point potential balance control method comprises the following steps of performing modulated wave decomposition on a three-phase reference voltage which is acquired after injecting a three-phase positive-sequence voltage into a zero-sequence voltage, obtaining a three-phase positive and negative modulated wave expression which satisfies middle-point potential balance; performing optimized selection on the zero-sequence voltage in a value range in a manner that the switching frequency of a power switch tube is used as an index; improving an interference resistance by means of a positive modulated wave compensation strategy; and comparing the compensated modulated wave with a carrier wave, and finally obtaining a switching sequence of all power switch tubes of the three-level NPC inverter. Compared with an existing single-modulated-wave zero-sequence voltage injection carrier wave modulation method, The point potential balance control method has a function of widening the value range of the zero-sequence voltage which satisfies middle-point potential balance and furthermore has no region with uncontrollable middle-point potential.

The invention provides a method for analyzing counter measures on influences of connection of a wind power plant on a partial electric network. The method comprise the following steps of analyzing the output characteristics and the load correlation of the wind power plant, and assessing the influences of the wind power plant on the partial electric network; analyzing influences on the reactive power and the load flow of the partial electric network after the wind power plant is connected, determining a reactive compensation strategy and a control strategy of the wind power plant; calculating a short-circuit current provided by the wind power plant, and calibrating related bus capacity and the interrupting capacity of a switchgear; assessing the transient stability of the partial electric network after the wind power plant is connected, and providing a transient stability control strategy of the partial electric network; analyzing whether all power quality indexes meet standard requirements or not after the wind power plant is connected, and determining feasible management strategies when the power quality indexes exceed the standard requirements. The method for analyzing the counter measures on the influences of the connection of the wind power plant on the partial electric network is comprehensive in analysis and high in practicability, lays a scientific base on effective assessment of grid connection influences of the wind power plant, and safe and stable operation of the electric network after the wind power plant is connected can be guaranteed.

The invention discloses a square wave compensation control method for the operating range of an enlarged cascaded H-bridge photovoltaic inverter and belongs to the field of photovoltaic power generation. The method mainly comprises the following steps of (1) independently controlling the direct-current-side capacitor voltage of each H-bridge unit and obtaining the active power instruction value ofa grid-connected current; (2) realizing the static-error-free control of the grid-connected current, and simultaneously generating the total modulating voltage of the inverter and the modulation degrees of all H-bridge units; (3) according to the square wave compensation strategy, calculating the modulation wave of each H-bridge module. Compared with published documents in the prior art, the normal operation of the power factor of an inverter unit is ensured when the input power of the cascaded H-bridge photovoltaic grid-connected inverter is not balanced seriously. Meanwhile, the fluctuation of the direct-current-side capacitor voltage of the enlarged cascaded H-bridge photovoltaic inverter is ensured to be small.

The invention provides an automatic charging system for a robot. The automatic charging system for the robot comprises an infrared transmitting tube, infrared receiving tubes, a DSP (digital signal processor) controller, an edge guiding module, an angle compensating module and a charging module; and the infrared receiving tubes are arranged in the front of the robot and at the rear of the robot. According to the automatic charging system and an automatic charging method for the robot in an embodiment, the single infrared transmitting tube is used for transmitting infrared signals, the edge characteristics of an infrared transmitting range are skillfully used, and butt joint guidance on the robot can be implemented by an angle compensation strategy. Because edge angle characteristics of different infrared transmitting tubes are different, when the automatic charging system is used for the first time, a tangent angle of the transmitting angle at a transmitting point requires to be measured manually. Even if an approach angle has deviation due to external interferences, a charging head is within a range of a charging socket through the angle compensation strategy. Deviation of an inserting angle can be compensated through a mechanical structure of a charging station. In addition, the invention also provides an automatic charging method for the robot.

The invention provides an error calibration method based on a genetic algorithm for a six-degree-of-freedom series robot, and relates to the error calibration method for the robot. The error calibration method based on the genetic algorithm for the six-degree-of-freedom series robot aims to solve the problems that in the prior art, multidata cannot be processed, an obtained error parameter has a certain limitation, some data with great errors are introduced, and then the accuracy of a whole data set is influenced, and the measuring difficulty and time are increased. The method comprises the steps of 1, establishing a real model of the robot; 2, calculating a robot error model of the robot and obtaining a matrix; 3, establishing an error optimization model; 4, obtaining an error parameter X of the robot; 5, searching for an optimal error parameter of the robot; 6, feeding the obtained optimal error parameter back to the robot according to an error compensation strategy, and the like. The error calibration method based on the genetic algorithm for the six-degree-of-freedom series robot is applied to the field of the error calibration method for the robot.

The invention discloses a video processing method and electronic equipment. The video processing method comprises the following steps of obtaining attitude parameters corresponding to the electronic equipment in a video recording process in real time through a sensor, making an angle compensation strategy for corresponding intake image frame data by utilizing the obtained attitude parameters, and subsequently carrying out corresponding angle compensation processing on the frame image according to the made angle compensation strategy so as to still keep a video recording picture stable and consistent in an attitude variation process of the electronic equipment when a video is played. Through the video processing method and the electronic equipment, the angle compensation is carried out in a display direction of the video recording picture based on the attitude parameters of the electronic equipment in the video recording process, so that the problem of intelligent screen rotation recording of the video is solved, the display direction of the recorded picture cannot change with the attitude of the electronic equipment during recording when the video is played, and the user experience is better.

The invention relates to a stream media data request transmission method for multimedia telephone peer-to-peer (P2P) video-on-demand. A combination of one or more of a node marking mechanism, a safety zone compensation strategy and a data request scheduling strategy is adopted, wherein the node marking mechanism marks corresponding nodes according to a response of P2P data nodes to a data request and acquires data from a high-quality P2P data node; the safety zone compensation strategy pre-detects a data insufficient situation in a buffer zone and supplies sufficient buffer data to data reduction playback by quickly downloading deficient data blocks to a content delivery network (CDN) server; and the data request scheduling strategy schedules a data transmission rate and a data block requesting sequence among data transmission channels established between a user node and the various P2P data nodes so as to acquire a minimum data transmission delay. By adopting the stream media data request transmission method, even a stream media data quantity is larger, continuous and smooth playback of stream media can be realized; and the stream media data request transmission method is economic and convenient and has a wide application prospect.

The present invention discloses a robust delay compensation grid-connected control method of an LCL inverter. The method mainly comprises three parts which are power feedforward control, voltage outer ring control and current inner ring robust delay compensation grid-connected control, wherein the power feedforward control can speed up the unidirectional transfer process from photovoltaic DC side energy to grid AC side energy, and the transient response of the system is accelerated, the voltage outer ring control is used for stabilizing DC side capacitance voltage, and robust delay compensation grid-connected control is employed by a current inner ring. The method comprises a capacitive current feedback delay compensation and zero pole delay compensation policy, the control delay of a system is effectively reduced, the robustness and dynamic performance of the system are improved, and a high quality grid-connected current feed-in grid is realized. According to the method, the LCL inverter has higher robustness and a fast dynamic response, and the need of an inverter grid-connected operation is satisfied.

The invention discloses a heavy numerical control machine tool thermal error compensation control system based on CPS (Cyber-Physical Systems) and a thermal error compensation method. The thermal error compensation control system comprises an embedded acquiring card, an operation controller and a numerical control connector, wherein the embedded acquiring card is used for acquiring the temperatureinformation of measuring points of a machine tool and the displacement thermal errors of a main shaft tool tip of the machine tool and sending data to the operation controller after preprocessing; the operation controller is used for substituting the received temperature data into a prediction mathematical model to calculate thermal error prediction values, processing the thermal error predictionvalues into real-time compensation values according to formulated compensation strategies and uploading the thermal error prediction values and the real-time compensation values to a cloud server through a wireless network, wherein the prediction mathematical model and the compensation strategies are remotely updated through the wireless network; and the numerical control connector is used for inputting the received real-time compensation values to a machine tool numerical control system through a NCUC bus, and the machine tool numerical control system reads the real-time compensation valuesin operation and processing of G codes, and controls of the machine tool to move in the X axis, the Y axis and the Z axis.

The invention relates to the technical field of stamping die manufacturing, in particular to a stamping springback full-profile compensation method for an automobile fender. The stamping springback full-profile compensation method comprises the following steps: S1, obtaining a basic springback simulation result based on a forward function model; S2, obtaining a full-profile springback compensationstrategy based on a reverse function model; and S3, carrying out reconstruction optimization and simulation verification on the tool body of the compensation process based on a full-profile springback compensation strategy. According to the stamping springback full-profile compensation method for an automobile fender, the design efficiency and precision of fender springback compensation are improved, and the actual part size debugging period is shortened, and the realizability, reliability and accuracy of stamping springback compensation are achieved.

The invention relates to an optimizing time synchronizing device for multi-channel clock sources. The optimizing time synchronizing device comprises at least two units identical in structure. In every unit, a global positioning system ground receiver (8) is connected with a counter (7), the counter (7) is further connected with a comparator (6) in the unit, a high-stability crystal oscillator (1) is directly connected with the counter (7) in every unit or connected with the counter (7) in every unit through a phase-locking frequency multiplier (2), and the comparator (6) in every unit is respectively connected with one input end of a multiplexer (4). The counter (7), the comparator (6) and a register (5) in every unit are respectively connected with a single chip microcomputer (3), and the output end of the single chip microcomputer (3) is further connected with the multiplexer (4). The optimizing time synchronizing device has the advantages that the comprehensive cost is low, algorithm adaptability is high, optimization of the multi-channel clock sources is supported, various time difference compensation strategies are supported, high-precision punctuality can be achieved, and time signal output is stable and reliable, and the like.