132 results about "Inverse method" patented technology

This invention provides a basin excavation inverse method. Its major construction step is the open excavation in retaining structure edge at the first step , and digs a kind of pot-style structure, and pour the top layer concrete of underground structure, and provides dug holes; then excavates in another way, it is a pot of architecture, and pours the top structure concrete of the underground two-story, and allows dug holes; following mining, and pouring the top three underground structure plate and the top four floors underground structure ; the bottom of base plate structure is divided into two parts ;it excavates scope of the bottom floor firstly, the pit digs to the bottom, pouring concrete, then the envelope around 6 ~ 10 meters pumps the excavation. This construction method is suitable for the large pit area, depth deeper large-scale construction projects, as it constructs conveniently, saves manpower and resources to improve the progress of the project, and shortens the construction periods.

The invention discloses a method for diagnosing a fault of a transformer on the basis of a clustering algorithm and a neural network. The method comprises the following steps that (a) the type of the fault is determined according to an IEC standard and a DL / T722-2000 guideline, and the characteristic quantities of a fault sample set are selected from an original sample set; (b) clustering is carried out on samples by utilizing a K-means clustering method; (c) an RBF neural network is established; (d) parameter learning is carried out to determine the number, the center position, the width and the output weight of hidden layers; (e) optimization training is carried out by adopting PSO to determine the positions of the centers of the hidden layers, and the number, the width and the weight of the hidden layers are determined by utilizing a test method, a minimum distance method and a pseudo-inverse method respectively; (f) training samples are input, the posterior probability is solved, and the type of the fault is judged. According to the method for diagnosing the fault of the transformer on the basis of the clustering algorithm and the neural network, the training samples and the test samples can be evenly divided from the total samples, more complete test on the neural network can be carried out by good test samples, and therefore the neural network can be evaluated correctly and reasonably.

A 3-D electromagnetic fast inversing method of object minimization includes confirming known object region according to known geologic data, setting up background conductivity combination according to known conductivity parameter and 3-D interpolation, calculating background field of said combination, inversing unknown region as per requirement of production, obtaining general field, carrying out 3-D interpolation on phase curve and actually measured conductivity curve, inversing frequency and fitting inversed frequency to obtain underground conductivity set of object.

The invention discloses a static and dynamic identification method for a dynamic parameter for a robot, which needs to provide a robot substrate six-axis force as well as the driving torque, the angular velocity and the angular acceleration of each joint. During static identification, a multidimensional matrix is built by the rotation transformation relationship between connecting rod coordinate systems of the robot by changing the configuration of a mechanical arm, a static identification model is built, and the product of the quality of each connecting rod and the coordinate of the centroid is solved with a least square method. According to a static identification result, a mechanical arm dynamics equation of a dynamics parameter decoupling form is deduced on the basis of the Newton-Euler algorithm. In the dynamic identification, each joint is planned to move in a specific combination mode, and the inertia tensor and the coordinate of the centroid from a tail-end connecting rod to a connecting rod 1 are successively identified with a pseudo inverse method so as to the full identification of the dynamic parameter for the robot. The parameter identification result disclosed by the invention comprises the mechanical arm joint characteristics, and therefore, the inertia parameter value in the practical work of the robot can be reflected.

The invention discloses a lossless data hiding method based on difference image histogram cycle spinning. The lossless data hiding method includes steps of encrypting, secret key transmitting and data recovery. During encrypting, an original image is divided into a plurality of sub image blocks at the transmitting end, cycle spinning operation is performed by aid of a sub block difference histogram to achieve step-by-step embedding of secret data, a secret image C' is formed and transmitted to the receiving end. During secret key transmitting, the size of sub image blocks, the length of embedded data and the embedding level L serve as a secret key to be distributed to the receiving end. During data recovery, the receiving end extracts the secret data step by step from the secret image C' in an inverse method of the embedding process, block difference and original image data are recovered, and secret data transmission and lossless recovery based on the image carrier are achieved. The lossless data hiding method overcomes the defect that the capacity of the original histogram spinning algorithm depends on a single peak point, and increases the embedding capacity through a cycle embedding method. Experimental results prove that the lossless data hiding method can well meet requirements for high capacity, low distortion and high efficiency.

The invention relates to a satellite attitude maneuver control method, in particular to a flexible agile satellite attitude maneuver rolling optimization control method. The flexible agile satellite attitude maneuver rolling optimization control method resolves the problems that when rapid maneuver of an existing flexible satellite attitude is carried out, nonlinearity is strong, various constraints are provided, and a flexible accessory vibrates easily, and then the control requirement can not be met easily. A nonlinearity state space equation comprising satellite attitude dynamics, kinematics and vibration of the flexible accessory is built and used for carrying out accurate prediction of future information of the satellite attitude. A weighing optimization index for achieving rapid maneuver of the satellite attitude and restraining vibration of the flexible accessory is built, design of an expectation control law is carried out through a nonlinearity model prediction control method, the planned expectation moment is shaped based on the input shaping technology, the manipulation law of a CMG group is designed through a robust pseudo-inverse method, the expectation control moment obtained after input shaping serves as input, a frame angular speed of each CMG is planned, and large-angle rapid maneuver control over the satellite attitude restraining vibration of the flexible accessory is achieved.

The invention discloses a method for improving robot parameter identification accuracy and belongs to the field of industrial robot control. The method comprises optimizing stimulation trajectories through a genetic algorithm; stimulate a robot to perform cyclical movement according to the optimized stimulation trajectories; sampling actual joint positions and actual torque data during moving and processing the data to obtain torque values, joint positions, joint speeds and joint accelerated speeds which are high in signal to noise ratio; establishing a dynamic linear model, and identifying all parameters related to joint dynamics through a weighted least square method. By the aid of the method, the actual trajectory Fourier series form is fit through an inverse method, and accordingly, speeds and accelerated speeds which cannot be obtained directly in experiments can be obtained conveniently, noise signals in sampling position signals and torque signals can be eliminated through an equalization method, the signal to noise ratio is improved and the robot parameter identification accuracy is improved.

In a non-destructive method for determining the internal structure of a heat conducting body, such as a cooling structure of a turbine blade, a flow medium is passed through the internal structure and the resultant thermal image on an external surface of the body is registered using a pixelised thermal image detector. Heat transfer coefficients and wall thicknesses of the internal structure are determined by means of a 1-,2-, or 3-dimensional inverse method that includes the numerical modelling of the surface temperatures using initial values for heat transfer coefficients and wall thicknesses and an optimisation of the values using an iteration method. In a special variant of the method, the spatial geometry of the internal structure of the body is determined by means of the same inverse method and a geometry model that is optimised by iteration. No prior knowledge of the internal geometry is required.

The invention relates to a well-constrained pre-stack elastic parameter inversing method for modulating supplemented subspace, belonging to the field of seismic log. The method provided by the invention has the advantages that: the computation time is shortened so that the running time is shortened and the cost is reduced; the processing parameters can be adjusted so that a better processing result can be obtained; the frequency-increasing data wave group detailed information is not abundant so that the wave group characteristics of original seismic events and the interlaminar information of original profiles are maintained and the resolution of the profiles is enhanced; the undue dependence on a stratified model is avoided to ensure that the information of combined reconstruction beside the well is preferably fitted with the log information, and the non-stratified information contained in seismic data can be fully reflected outside the well; therefore, the problem of matching the seismic data of reservoir stratums (stratums such as fluvial facies reservoir stratum, carbonatite pore and fissure and hole intensive belt and the like ) with reticular characteristics with the well information is solved.

A method of building a set of experimental prediction model that requires fewer experimental frequency, shorter prediction time and higher prediction accuracy by using the advantages of combining the experimental data of Taguchi method and neural network learning is disclosed. The error between the experimentally measured result of photolithography and the simulated result of the theoretical model of near field photolithography is set as an objective function of an inverse method for back calculating fiber probe aperture size, which is adopted in the following Taguchi experiment. The analytical result of Taguchi neural network model of the present invention proves that the Taguchi neural network model can provide more accurate prediction result than the conventional Taguchi network model, and at the same time, improve the demerit of requiring massive training examples of the conventional neural network.

The invention provides a tracking-while-drilling controlling method for a landing track of a shale gas horizontal well. According to a stratum inclination angle in the track construction direction, the vertical thickness of the well is combined and compared, the vertical distance from a kickoff point to the top of a target body is calculated and a well track is designed; well inclination is distributed and is adjusted in time, then an inverse method is adopted; and well inclination data corresponding to every stratum marker bed is determined as a landing practical drilling track controlling basis. When the practical drilling track drills to a characteristic point of the gamma curve, the practical drilling well inclination is matched with the characteristic point designing well inclination and then construction is conducted according to the designed track; the practical drilling inclination is not matched with the characteristic point designing well inclination, track parameters are calculated and the track is smoothened in order that the next characteristic point and design can meet the requirement of matching with each other until the landing construction is finished. The landing well hole track formed by the tracking-while-drilling controlling method is smooth; the friction resistance of the landing well region is reduced effectively; drilling speed is improved; it is guaranteed that the well hole track can extend smoothly and the risk of the horizontal well construction operation is reduced.

The invention provides an inverse kinematical solution method during the installation process of an overhaul robot arm of a steam generator; wherein, the definitions of Alpha, Beta, and Gamma are as follows: at the initial stage, a base coordinate system is in the same attitude with a world coordinate system, then the base coordinate system revolves around the Y axis for the Alpha angle, next revolves around the X axis for the Beta angle, and finally revolves around the Y axis again for the Gamma angle, so as to obtain the ultimate attitude of the base coordinate system. The respective positions of the articulation points are: B point is the arithmetic endpoint of the robot arm, C, D, E, F, G, and H points are respectively the sixth to first articulation points, and I point is toe arithmetic endpoint; first, the coordinates of the articulation points of the robot arm are solved, and the coordinates of B, C and D points are resolved by means of the normal solutions during installation process; then, a vector HI is acquired based on the coordinate of I point and the attitude angles Alpha, Beta, and Gamma, so the coordinate of H point can be deduced; next, the coordinate of F point is solved; finally, the turn angles Theta (i) of the articulation points can be resolved (wherein, I=1, 2, 3, 4, 5, 6). The inverse kinematical solution method in the invention has the advantages of avoiding building up the kinematical equation of the robot arm, greatly reducing the amount of calculation, quickening the operational speed, and solving all the solutions.

The invention discloses an attitude-orbit integrated thrust distribution method for a satellite, and belongs to the technical field of satellite control. After the installation layout of a thruster is determined, a mathematical model of thrust distribution is built, and the initial solution of thrust distribution, namely the initial thrust distribution scheme, is obtained based on the conventional pseudo-inverse method; then, grouping is performed based on the initial solution, and the thrust distribution scheme based on a chain type distribution revised pseudo-inverse method is obtained; and finally, a thrust distribution optimization index is designed, overall algorithm optimization is realized with the combination of various indexes of the thruster, and thrust distribution is optimized. According to the method, the integrated control task of the satellite can be effectively accomplished within the load range configured by the thruster, fuels are effectively saved, the thrust distribution error brought by thrust configuration is reduced, and the control precision of the thrust is improved.

The invention discloses a construction method of a tank wall of an oil tank. An inverse method is employed in the construction of the tank wall. The method comprises the steps of: marking a circle on a tank base plate, with a diameter being equal to that of the tank wall and arranging a channel steel and a baffle plate on the tank base plate; assembling a first ring wall plate, arranging an expansion ring back rod below the first ring wall plate and coupling and welding an edge angle iron of the first ring wall plate; mounting a tank top; uniformly disposing lifting pillars on the tank base plate and connecting each lifting pillar with a central umbrella post through a transverse pull bar for fixation; mounting a second ring wall plate, including the steps of firstly placing the second ring wall plate on the outside of the first ring wall plate for assembly, welding a longitudinal seam of the second ring wall plate, coupling and welding a circular seam between the first ring wall plate and the second ring wall plate, taking off the expansion ring back rod after the welding and arranging the back rod on the second ring wall plate; assembling each ring wall plate at the upper part in a successive manner according to the previous step; and finally coupling and welding a bottom ring wall plate and a tank bottom plate. The construction method of the invention not only improves construction efficiency but also effectively enhances construction quality.

The invention relates to an adaptive fault tolerant control method considering input constraints of an actuator for a hypersonic flight vehicle. The method comprises the following steps of firstly, establishing a standard longitudinal dynamics model of the hypersonic flight vehicle and decomposing the model into speed, height and attitude subsystems; secondly, establishing an air vehicle actuatorfault model with generality, and compensating input constraint characteristics of the actuator by constructing a smoothing function; and thirdly, respectively designing an adaptive compensation controller and an adaptive law for three subsystems through a dynamic inverse method, a backstepping method and a sliding mode control method. According to the method, the stability of longitudinal model parameters such as air vehicle speed, height and the like is guaranteed in a level flight working state when the hypersonic flight vehicle with the input constraint characteristics of the actuator has an actuator fault, and the method has the advantages of strong fault-tolerant capability and robustness to external disturbance and the like.

A method is provided to distinguish two blended but different waves in a structure, such as compressional and shear waves, by measuring their corresponding wavenumbers and wave speeds. Other characteristics of the two waves may also be measured such as the propagation coefficients of both waves. All measurements can be calculated at every frequency for which a transfer function measurement is made. The measurements do not depend on the resonance frequencies of the structure and do not require curve fitting to the transfer functions.

The invention discloses a milling residual stress measuring method based on deflection changes and an inverse method. Corrosion delamination is carried out on a stress layer for multiple times, the thickness of a material layer removed through corrosion each time is measured by a vernier caliper, a part is scanned on a machine tool by using a laser displacement sensor to measure the change of the deflection of the part after the corrosion of each time, the change of the bending moment generated by the stress layer is obtained according to the change of the position of the neutral layer in the part, the residual stress value is calculated forwards in an inverse mode by combining the changes of measured deflection, and lastly the stress values of all the stress layers before the self-balance of the stress are obtained. The milling residual stress measuring method based on the deflection changes and the inverse method is simple in operation and reliable in result, and the used equipment is low in price.

The invention belongs to the technical filed of real-time positioning of a distributed multi-point positioning monitoring system and particularly relates to a positioning accuracy resolving method for a distributed multi-point positioning monitoring system. The positioning accuracy resolving method includes determining the position information of the receiving station master station of a target, differentiating the position information of the area to be positioned, solving the correlation coefficient matrix of the target and the receiving station master station position of the target and the target and the receiving station slave station position, calculating the error estimation value of the area to be positioned by means of the pseudo inverse method, and finally obtaining the positioning accuracy of the area to be positioned. The set measured error is zero-mean after being corrected by the system, the target receiving station error elements and the station address errors are not related, so that the complexity of the positioning accuracy resolving method is greatly reduced and the efficiency of positioning accuracy resolution is improved.

The present invention relates to a two-step integral inverse method for determining a geoidal surface based on band-limited aerial vector gravity. The method includes the following steps that: based on a generalized horizontal boundary value theory, band-limited aerial vector gravity at the altitude of a flight line is adopted to calculate band-limited aeronautical disturbing potential; and an inverse Poisson integral model is adopted to extend downwards the band-limited aeronautical disturbing potential to a sea surface, so that band-limited sea surface disturbing potential can be obtained, and the band-limited sea surface disturbing potential is converted into the geoidal surface through using the Bruns formula. The method of the invention is reasonable in design. With the method adopted, a new solution is provided for calculating the geoidal surface based on the band-limited aerial vector gravity, a calculation function for determining the geoidal surface by using the band-limited aerial vector gravity is realized, and the accuracy of the obtained geoidal surface can satisfy engineering application requirements.

The invention discloses a method for digging earth to form space in an inverse method for enlarging a basement. The method is applied to a basement foundation ditch of a support system which forms the peripheric space enclosing structure of the basement, supporting steel pipe columns in the middle, the floor slab structure of + / - 0.000 floor and the floor slab structure of the first floor underground by construction. A floor slab crossing the floor along the periphery of the basement on the second floor underground is first constructed, then a steel pipe is used for upwards and obliquely supporting the steel pipe column which is topped to the inward floor of the first floor underground from the steel pipe column at the side of the floor slab crossing the floor, a mutual opposite vertex bracing structure which can transmit side pressure transmitted from the peripheric space enclosing structure of the floor slab of the first floor underground first by the floor slab which is constructed on the second floor underground and then by the steel pipe which is obliquely supported is formed, thereby space in which earth for two floors can be fully dug is formed. The invention also discloses a supporting structure. By the actual operation of the method, under the circumstance that the floor slab structure of the second floor underground does not need to be fully constructed, enough upper lever rigidity can be ensured to enable the earth of the second floor underground and the third floor ground of the basement to be dug once by a large type pullshovel excavator, thereby the degree of advancement for digging the earth of the basement is greatly enhanced, and obvious economic benefit and social benefit are obtained.

The invention discloses a construction method for underground building combining a rotary jet grouting open caisson method and a semi-inverse method, which relates to the building construction technical field. An underground structure outer wall is integrally preformed on the ground, and the construction method comprises the following construction steps: firstly, a groove is dug, and a guide wall is constructed; secondly, prestress is applied to a preformed underground structure outer wall: after the concrete strength of the preformed wall reaches 70 percent, the prestress is applied and the preformed underground structure outer wall is locked with a prestressed anchorage device; thirdly, jet grouting open caisson is performed to the whole preformed outer wall; fourthly, when the preformed outer wall is sunk to a set depth, mortar is changed to perform the mortar solidifying at the groove bottom and on the groove wall; fifthly, the underground structure is constructed through the semi-inverse method. The construction method adopts the integral jet grouting open caisson method to perform the underground structure, which not only saves a great amount of construction investment and guarantees the security and the quality, but also accelerates the construction progress and shortens the construction period. The construction method is particularly suitable for the rapid construction of underground buildings, such as the basement of a large-scale civil architecture, a public underground garage and a subway station.

The invention provides a method for acquiring multispectral images based on a digital camera. The method includes the steps that firstly, an illumination shooting environment with good illumination uniformity and stability is set up, and the parameters of the focal length, white balance, the aperture, the shutter speed, the ISO value and the like of the digital camera are manually set; on the basis, a training sample color card and a digital image of a target sample are acquired; prediction from an RGB value to an XYZLMS value is achieved through a polynomial model based on a local training sample, finally prediction from the XYZLMS value to a spectral value is achieved through a pseudo-inverse method, and then the multispectral images are acquired based on the digital camera. The method can be widely applied to acquiring multispectral images in the application of digitized book reservation of cultural relics and historic sites, cultural works of art, history documents and the like, machine vision, tele-medicine, spectrum color management, detection of animal and plant diseases and insect pests and the like.

The invention provides a spectrum reconstruction method based on a weighted measurement matrix, comprising the following steps: S1, acquiring the spectrum values of a training sample and a test sample; S2, acquiring the camera response values of the training sample and the test sample; S3, reconstructing the spectrum value of the test sample using a pseudo-inverse method, a wiener estimation method and a principal component analysis method respectively, and getting corresponding measurement matrixes; S4, calculating the chromatic aberration between each of the spectrum values obtained through reconstruction using the pseudo-inverse method, the wiener estimation method and the principal component analysis method and the spectrum value of the test sample; S5, weighting and adding the spectrum values obtained through reconstruction using the pseudo-inverse method, the wiener estimation method and the principal component analysis method to get a new spectrum value; S6, calculating the chromatic aberration between the new spectrum value and the spectrum value of the test sample; S7, adding the weight corresponding to the minimum chromatic aberration in S6 to the corresponding measurement matrixes, and adding three values obtained together to get a measurement matrix M; and S8, using the measurement matrix to reconstruct the spectrum value.

A robust self-adaptive dynamic surface control method for an adjustable metal cutting system is characterized by comprising the steps of description of an adjustable metal cutting system mathematical model, a hysteresis model and a neural network system, design of a self-adaptive dynamic surface controller and the like. By means of an introduced error transformation function, control accuracy can be specified at will, so that accurate control over the cutting depth of a cutter is realized; under the condition that a system model is not completely known, approach to unknown terms is realized through an RBF neural network; estimation of the norm of an unknown parameter vector is used for replacing estimation of an unknown parameter ground vector, so that the computation burden of the system is greatly relieved; by the adoption of the strategy that the self-adaptive dynamic surface technology is combined with the error transformation function and an RBF, the hypothesis of time lag is relaxed, it is guaranteed that tracking errors and the transient process can be within any specified index at the same time, the problem of 'differential explosion' of the inverse method is eliminated, semi-global uniform ultimate boundedness of system signals is guaranteed, and the robust self-adaptive dynamic surface control method has the advantages of being scientific and reasonable, high in control accuracy, applicable and the like.

The invention provides a local structural dynamical modeling method and a device. The method is adopted for solving the problems of big data volume, low calculation efficiency and difficulty in locally dynamical responding and finely analyzing as required of the present dynamical modeling. The method comprises the following steps: dividing a whole structure into a first structure and a second structure; establishing an interface multipoint restriction equation for the first structure under the first grid and the second structure under the second grid according to the finite element stiffness matrix and mass matrix of the first structure and the finite element stiffness matrix and mass matrix of the second structure; confirming a vibration mode of the first structure and a vibration mode of the second structure according to the equation; and confirming a deformation compatibility matrix between the DOF (Degree of Freedom) modal displacement of the first structure and the DOF modal displacement of the second structure according to a Moore-Penrose pseudo-inverse method, thereby confirming a dynamical equivalent support effect matrix of the second structure and a fine dynamical finite element model of the first structure.

The invention discloses a modeling method for an analytical model of equivalent and linear damping coefficient of a magnetorheological damper. The modeling method is characterized by comprising the following steps: acquiring sampled data of the magnetorheological damper through MTS mechanics measuring system experimentation; utilizing dissipation energy in a period of the magnetorheological damper to calculate equivalent and linear damping coefficient of the magnetorheological damper in different working conditions; adopting linear fitting and power function fitting to construct relation of parameters of three independent working conditions to the equivalent and linear damping coefficient respectively; conducting coupling calculation to acquire analytical models of equivalent and linear damping coefficients of the magnetorheological damper in the three independent working conditions; adopting least square pseudo-inverse method to identify the parameters to be identified of the analytical models of the equivalent and linear damping coefficients with the assistance of experimentation sampled data. The modeling method can be used for modeling an equivalent dynamic model of the magnetorheological damper, can be used for stability analysis of a structure system in which the magnetorheological damper is mounted, and can be used for predicting and determining the property of the magnetorheological damper.

The invention provides an off-line compensation method for the contour error of the machining path of a four-axis lathe, which belongs to the field of contour error compensation of numerical control machine tool processing. The invention relates to the off-line compensation method for the processing path contour error, and the machining precision of the closed closed-loop four-axis numerical control lathe is improved. The method uses an initial turning code to generate a theoretical cutter location point and a theoretical tool axis vector. A four-axis lathe Jacobian matrix is constructed. Theactual speed of a feed axis is calculated offline, so as to estimate the follow-up error of the feed axis of the lathe. An actual cutter location point and an actual tool axis vector are calculated. Three non-uniform rational B-spline curves are used to fit the theoretical cutter location point and a tool axis mark point. A tangential error inverse method is used to estimate the foot point of theactual cutter location point to a theoretical cutter location point curve. The contour error of the cutter location point and the contour error of the tool axis vector are calculated. Finally, the follow-up error of the feed axis is pre-compensated. The method can realize the pre-compensation of the contour error of the closed closed-loop four-axis numerical control lathe, and has the advantages of convenient implementation and obvious effect.

The invention discloses a quick and precise elongation control method for a temper mill. Double closed-loop control systems are adopted by the method, an inner loop control system is responsible for rolling force control, and an outer loop control system is responsible for elongation control including dynamic compensation control. The rolling force closed-loop control system adopts a mode of sum rolling force control and difference rolling force control of an operating side and a transmission side, and a hydraulic cylinder servo valve adopts a leakage compensation integral control mode. An elongation control loop adopts a dynamic variable-gain adaptive control method to calculate deviation of rolling force for correcting controller gain in real time by means of an integral inverse method. A mathematical model between speed fluctuation and elongation is set up aiming at the problem of high fluctuation of the elongation in a decelerating phase, and elongation control is jointly completed by the rolling force pre-control compensation control method and elongation closed loops.

The invention provides a tracking and real-time obstacle avoidance reaction planning algorithm applied to an industrial robot. The tracking and real-time obstacle avoidance reaction planning algorithmcomprises the steps: 1, the to-be-tracked curve pose, and the real-time distance between a tail end rigid body and an obstacle are input; 2, mapping from a robot joint space to a working space is given through forward kinematics; 3, the obstacle is detected through a visual sensor, and the distance to the obstacle is calculated; 4, the path is planned, and the rigid body of the working space is subjected to tracking and obstacle avoidance; 5, a joint angle is calculated according to a Jacobian pseudo-inverse method in the joint space; 6, the angular constraint problem is handled through a quick search spanning tree; 7, constraint is detected, if the constraint is not met, the step 6 is repeated, and if the constraint is met, the step 8 is executed; 8, a target is reached, the joint angleis obtained, the joint space control moment is calculated accordingly, if the target is reached, the algorithm process is completed, otherwise the step 9 is executed; and 9, an initial point is updated, and executing is conducted again from the step 3.

The invention discloses a calculation method for harmonic current of a direct-current side of a hybrid bipolar direct-current transmission system. The calculation method includes the steps: (1) performing equivalent transformation to obtain an equivalent three-pulse voltage source corresponding to an LCC (line-commutated converter) and an equivalent passive circuit corresponding to an MMC (modular multilevel converter); (2) sectioning a direct-current transmission line and a ground wire thereof, and calculating an admittance matrix of each subsection to obtain an admittance matrix of the whole direct-current transmission line by a recurrence method; (3) building a systemic direct-current network according to the equivalent three-pulse voltage source, the equivalent passive circuit and the direct-current transmission line to obtain node voltage of the front end and the tail end of the direct-current transmission line according to the admittance matrixes; (4) acquiring node voltage of each subsection node of the direct-current transmission line by an inverse method according to the node voltage to obtain the harmonic current of the direct-current side. Calculation efficiency of a direct-current loop is remarkably improved on the premise of ensuring effectiveness.