184 results about "Piecewise linearization" patented technology

The invention discloses a three-dimensional formation reconfiguration method for multiple unmanned aerial vehicles based on particle swarm optimization and genetic algorithm. The method considers the position of the unmanned aerial vehicle in the ground coordinates and the speed, track angle and course angle of the unmanned aerial vehicle when establishing a formation model, carries out subsection linear disposal of the control input of each flying unit in the unmanned aerial vehicle, replaces the approximate subsection linear control input with the continuous control input, then carries out global search by the genetic algorithm, subsequently carries out partial searching by the particle swarm optimization algorithm, on the base thereof, the particle swarm optimization is used to guide the genetic algorithm to search a global optimum solution so as to figure out the subsection linear control input. Compared with the traditional method, the method provided by the invention has good real-time performance and rapidity and can be used for solving the formation reconfiguration problem of multiple space robots under complex and dynamic environment.

The invention particularly relates to a modeling and system planning method for a gas power grid combined multi-region comprehensive energy system. The method comprises the following steps: S1, establishing a coupling model of a power grid, a gas net, and a power grid-gas net and a multi-region comprehensive energy system model combined with constrained gas net-power grid; S2, establishing a planning model for optimal economic operation of a gas net-power grid combined multi-region comprehensive energy system, aiming at minimizing the total system operation cost; S3, converting the mixed integer nonlinear programming model in the model into a mixed integer second-order cone programming model by using a second-order cone programming method; performing nonlinear quantity linearization processing in the incremental piecewise linearization method model; and therefore, a large-scale mixed integer second-order cone programming model is established by taking the minimum total system operationcost as a target; and S4, a commercial planning problem solver is adopted to solve the large-scale mixed integer second-order cone programming model, and the optimal output and the total system operation cost of each unit in the multi-region comprehensive energy system are obtained.

A method of constructing a piecewise linear engine performance model, comprises the steps of:

• • (a) providing a non-linear engine performance model which iteratively calculates engine performance variables y from a plurality of sub-models, each sub-model representing the performance of a component of the engine;
  • (b) defining a plurality of engine power conditions, each engine power condition being defined by one or more engine state variables x;
  • (c) for each of the engine power conditions, using the non-linear engine performance model to determine partial derivatives δy of the engine performance variables y with respect to engine control variables u and with respect to the engine state variables x, the values of the partial derivatives δy being determined so that, on integrating the partial derivatives δy, the error between steady state values for the engine performance variables y calculated by the non-linear engine performance model and steady state values for the engine performance variables y calculated from the integrated partial derivatives δy is reduced or eliminated; and
  • (d) constructing a piecewise linearised engine performance model in which calculation of the engine performance variables y involves combining each of the engine control variables u and the engine state variables x with the respective partial derivative δy.

The present invention relates to a comprehensive energy system day-ahead economic dispatching method, by which the technical problem that the comprehensive energy utilization efficiency is low due tothe fact that an existing analysis method takes insufficient consideration of the multi-energy coupling effect of heat, electricity and gas can be solved. The method comprises the following steps of S100, establishing an energy efficiency model with economic benefit maximization as a target to meet the requirements of different users for electricity and heat under supply and demand balance and operation constraint conditions; S200, establishing a model objective function, taking the total profit maximization as an objective function, i.e., the total system cost is subtracted from the energy selling profit, wherein the total cost comprises the operation cost of power supply, heat supply and gas supply, the starting cost and the shutdown cost; S300, establishing a model constraint condition,wherein the model needs to meet two types of constraints of the system operation constraint and the operation constraint of each device; and S400, performing linear conversion on the model. Accordingto the method, the segmented linearization is adopted to carry out conversion solution, a good effect is achieved, and important guidance can be provided for researching comprehensive energy system optimization scheduling adapting to the marketization environment.

The invention discloses a sinus heart rate turbulence trend detection method based on piecewise linearization. The piecewise linearization is adopted for specifically analyzing whether the variation trend of sinus heart rate accelerates first and then decelerates after premature ventricular contractions or not. The method includes the steps: (1) electrocardiosignal preprocessing; (2) self-learning process for first 10 seconds; (3) HRT (heart rate turbulence) sample collection; (4) piecewise trend analysis; and (5) turbulence trend representation based on a cloud model. The variation trend of the sinus heart rate at the RR interval is detected by means of piecewise linearization, and the turbulence trend is further represented by natural language through the cloud model. By the aid of an MATLAB (matrix laboratory) simulation tool, signals in an MIT-BIH heart beat irregularity database are selected for verification, and the variation trend of the sinus heart rate after single-time ventricular premature beat can be detected correctly. In addition, using the exponential smoothing method to predicate QRS complex occurrence positions to facilitate detection of QRS complex, and using a template for judging sinus heart beat is simple to implement and suitable for real-time treatment.

The invention provides a global time optimal trajectory programming method of industrial robot dynamic speed regulation. The global time optimal trajectory programming method comprises the steps thattrajectory points which may overrun are detected in advance by a searching mechanism based on iterative backwards of a fixed searching range, the trajectory points are divided into three classes according to the overrun conditions, corresponding algorithms are provided by a nonlinear problem segmentation linear idea, and particularly when a joint deceleration overruns, pushback and nudge of the trajectory points and a peak cut algorithm are combined to perform speed regulation. Algorithm dynamic speed regulation enables the overrunning trajectory points to meet constraint requirements, starting points of the searching range are continually issued to perform, and synchronous operation of searching detection, dynamic speed regulation and trajectory execution is ensured. By performing smoothing and limiting regulation on the velocity of movement and acceleration of a robot cartesian space and joint space synchronously, an original trajectory is guaranteed to move at a reasonable speed andin a constraint condition range; and time optimal of dynamic speed regulation is realized, smooth and efficient motion of the robot in a whole space is ensured, and the precision and operating efficiency of the robot are improved.

The invention discloses a real-time yield prediction method for a hydrocracking device. Field real-time data are processed with a data reconciliation technology, and hydrocracking reaction kinetics parameters are corrected in real time in combination with an improved differential evolution algorithm, so that a mechanism model can accurately describe the actual running condition of the device. On the basis of the corrected model, effects caused by key operation/process conditions such as the raw material density, the sulfur content, the nitrogen content, the reaction temperature, the pressure, the hydrogen-to-oil volume ratio and the like on hydrocracked products are analyzed. Piecewise linearization is performed according to the effect trend, a linear equation is solved, corresponding Delta-Base yield data are acquired, the operation condition is associated with the Delta-Base data with a neutral network modeling technology, a yield surrogate model is established, the yield data calculation speed is increased, real-time prediction of the yield of products of the hydrocracking device is realized, and theoretical support is provided for establishing an accurate plan optimization PIMS (process industry modeling system) model.

A piecewise linear method for analyzing supercavitation navigation body kinetic characteristics includes the steps that step1, a supercavitation navigation body kinetic model is built; step2, piecewise linear fitting is performed on a non-linear sliding force function in the supercavitation navigation body kinetic model to obtain a linear sliding force function; step3, parameters of the supercavitation kinetic model are set; step4, the supercavitation kinetic model with the piecewise linear sliding force Fp function is adopted for obtaining a sole balance point of a supercavitation navigation body, linearization is performed on a system at the balance point to obtain a jacobian matrix of the system and a characteristic equation at the balance point, characteristic values of the system are obtained, and the balance point of the system is judged to be an unstable saddle focus. By the adoption of the piecewise linearization of the sliding force function, the supercavitation navigation body kinetic model is simplified, so that the balance point position and stability conditions of the model have concise analytical expressions, and the supercavitation navigation body kinetic characteristics are analyzed more conveniently.

The invention relates to an economic scheduling method for a micro-grid system. Based on the minimum operation cost as the control target, target functions and corresponding constraint conditions in three operation states of grid-connected operation, isolated-grid long-term stable operation, and isolated-grid short-term operation are respectively built, the built target functions cover device operation costs such as the device depreciation cost, the fuel cost, the maintenance cost, the start-stop cost, and the environmental protection cost etc. and various comprehensive cost influence factors such as the power purchase and selling cost, the load-shedding cost, and the line loss cost etc. via modeling of various devices in the system, non-linear problems are converted to linear problems by employing a sectional linearization processing method, decision variables such as 0 and 1 are introduced to convert quadratic constraint in the constraint to one-time constraint, and the solution is obtained in a time stratified manner. According to the method, various optional scheduling modes are provided, the applicability is high, the accuracy of calculating results is high, the calculating speed is fast, and the method can be applicable to large-scale micro-grid optimization scheduling.

The invention discloses a multi-unmanned aerial vehicle three-dimensional formation reconfiguration method based on an artificial bee colony (ABC) algorithm, and belongs to the technical field of unmanned aerial vehicle control. The method comprises the following steps: firstly, establishing a motion model of an unmanned aerial vehicle and then giving out mathematical description of optimal time control of three-dimensional formation reconfiguration; and after piecewise linearization control input is carried out, carrying out unmanned aerial vehicle three-dimensional formation reconfigurationby using an ABC algorithm. Compared with the prior art, the method disclosed by the invention has the advantages that the searching time of unmanned aerial vehicle formation reconfiguration through the ABC algorithm is shortest, so that the rapidity of the unmanned aerial vehicle formation reconfiguration is realized; and the ABC algorithm is a global search method which can avoid falling into local optimization, so that the accuracy of the unmanned aerial vehicle formation reconfiguration is improved.

The invention discloses a full-process modeling method for an oil refining process. Based on the mechanisms and running characteristics of all production devices in the oil refining process and a corrected model, the influence of key operation/process conditions of all the devices on the product yield is analyzed. Piecewise linearization is carried out according to the influence trend, a linear equation is solved, corresponding Delta-Base yield data are obtained, a neural network modeling technology is combined, operation conditions and the Delta-Base data are related, a yield surrogate model is built, the yield data calculating speed is improved, real-time prediction on the product yield in the oil refining process is achieved, and theoretical supports are provided for building a precise plan optimized PIMS model.

A sensitivity analysis based interaction cost calculation method for a microgrid and a power distribution grid comprises the following steps of: acquiring basic structure and parameter information of the microgrid participating in interaction; forecasting the output and the load power of a distributed power supply in a scheduling period, and acquiring time-sharing electricity cost information of the power distribution grid; considering the electricity purchasing cost of the microgrid in the scheduling period, the electricity sell gain and the power generation cost of the distributed power supply by taking minimum running cost of the microgrid as a target function, and building a microgrid running optimal scheduling model; setting a constraint condition of a microgrid optimal scheduling problem; solving a microgrid optimal scheduling mode formed by the target function and the constraint condition by using an optimization tool to obtain running cost corresponding to a scheduling plan; acquiring interactive time frame information of the power distribution grid; and respectively calculating positive interaction cost and negative interaction cost of the microgrid, and acquiring the relation between the interaction capacity and the interaction cost during the positive interaction of the microgrid through piecewise linearization. By the method, the interaction between the microgrid and the power distribution grid is achieved at the minimum cost.

The invention discloses a time series trend feature extraction method based on an important point double evaluation factor, comprising: regarding a time series piecewise linear representation as basis, defining an important point as an alternative set of time series segmentation points, calculating an important point distance factor and a trend factor, using the distance factor to measure the relative degree of difference and using the trend factor to measure its impact on the overall trend globally, using a comprehensive evaluation model to evaluate the importance of each important point to the overall trend to select the segmentation points, and finally connecting adjacent segmentation points to obtain a segmented trend representation of the time series. The invention proposes the concept of a time series important point distance factor, and combines the two evaluation factors to evaluate the important points of the time series, which overcomes the shortcomings of single evaluation functions and locality of the existing piecewise linearization method, may effectively weaken the noise interference, retain the time series change trend feature, and has fast processing speed and higher extraction precision than the existing method when the number of segments is the same.

The invention provides an advanced design method for a numerical simulation analysis platform of a control system of an aero-engine. Based on a MATLAB/Simulink platform, the simulation platform whichcan be used for aero-engine controller design analysis and transient state performance testing is developed. An architecture of the platform is divided into four layers, all the layers are independent, and a user can conduct targeted modification, optimization and expansion according to different simulation targets to facilitate interaction among different simulation platforms. The method has a good human-computer interaction interface, the independence of all modules is good, and separate testing of the modules and further improvement by the user are facilitated. Meanwhile, multiple methods can be adopted for the simulation platform for building an engine piecewise linearized model, and adapted to conducting optimal design on parameters of a controller, the improvement condition of the control effect can be analyzed, and the simulation platform which is accurate, efficient, universal and flexible is provided for the aero-engine and the control system thereof.

Information handling system display brightness adjustments in response to ambient light sensed by an ambient light sensor are calibrated by reference to brightness levels, such as manually selectable brightness levels stored on the display. A brightness calibration module running on the information handling system or a controller of an inverter associated with the display generates an ambient light response from the manually selectable brightness levels, such as with a piecewise linearization of each pair of sequential manually selectable brightness levels. The inverter automatically adjusts display brightness by correcting ambient light levels sensed by the ambient light sensor according to the ambient light response.

The invention provides a practical decoupling electromagnetic transient state modeling method for describing the nonlinear magnetic saturation property of a super/extreme-high voltage magnetically controlled shunt reactor (a high-voltage magnetically controlled shunt reactor), comprising the steps of: describing nonlinear magnetic circuit property with arc hyperbolic functions; decoupling a coupling magnetic circuit equation by providing and utilizing a magnetic-flow substitute algorithm; and establishing an equivalent magnetic-flow difference electromagnetic transient state modeling method. The invention not only accurately reflects the continuously smooth regulation property of a saturated magnetic circuit of the super/extreme-high voltage magnetically controlled shunt reactor and prevents the numerical oscillation of piecewise linearization algorithm, but also can meet the requirements of real-time/faster-than-real-time simulation computation without modifying an admittance matrix and influencing computing speed under the condition of large-range continuous regulation, provides a necessary simulation tool for the real-time electromagnetic transient state computation of the super/extreme-high voltage magnetically controlled shunt reactor and also initiates a new idea for the real-time electromagnetic transient state modeling method of a nuclear element.

The invention discloses a hydraulic motor remote control system of a towing winch, which comprises a remote control handle, a programmable logic controller (PLC) signal processing unit, a proportional valve controller, an electromagnetic pressure proportional valve and a hydraulic motor which are sequentially connected, wherein the electromagnetic pressure proportional valve comprises a take-up electromagnetic pressure proportional valve and a releasing electromagnetic pressure proportional valve which are connected in parallel; a signal linear processing method adopted by the PLC processing unit is a segmented linear processing method; output signals of the proportional valve controller are pulse-width modulation (PWM) signals; and the control current of the electromagnetic pressure proportional valve is 140 to 400 mA. The hydraulic motor remote control system has the characteristics of no remote control signal distortion, relatively more stable hydraulic motor output pressure, simple control method, relatively lower cost and convenient debugging.