51 results about "Natural coordinate system" patented technology

The invention discloses a six-phase permanent-magnet synchronous motor (PMSM) model predictive control method comprising establishing a state space model of a six-phase PMSM by performing discretization on the six-phase PMSM in a natural coordinate system; by acquiring the state information at the kth time, using the current in the fundamental wave subspace as a master control amount and using the current in the harmonic wave subspace as an optimizable controlled amount, establishing an objective function based on torque maximum and harmonic current minimum. The six-phase PMSM model predictive control method is established on the basis of a completely-discretized six-phase PMSM mathematic model and the essential discreteness of the method is liable to digital realization. An experiment verifies the fast responsiveness and the good robustness of the method in real control.

The invention discloses an automatic driving control method and device, a vehicle and a storage medium. The method comprises the following steps: determining a planned path and a planned speed of automatic driving according to a first objective function under a natural coordinate system; determining a target trajectory of automatic driving according to the planned path, the planned speed and a second target function; and solving a control sequence according to the target trajectory, and controlling automatic driving of the vehicle according to the control sequence. According to the technical scheme, on the basis of the planned path and the planned speed, the target trajectory of automatic driving of the vehicle is accurately determined according to the target function, then automatic driving of the vehicle is controlled according to the target trajectory, and the reliability of automatic driving is improved.

The invention provides a forecasting method for vehicle body structure-acoustic coupling based on a smoothed finite element boundary element method. The method comprises the following steps: generating a vehicle body structure-acoustic grid model; utilizing the smoothed finite element method to perform smooth processing on the stress field in a shell unit; adopting a mixed integral method to perform separate integral of shearing items subjected to shearing strain in the shell under a natural coordinate system; building a smooth Galerkin weak form of a vehicle body shell structure kinetic equation, and obtaining a dynamic equation after the weak form is subjected to discrete processing; creating an acoustic realistic model by using the boundary element method; according to the continuous displacement and pressure of the coupling interface, obtaining a structure-acoustic coupled smoothed finite element boundary element model; performing simulation forecasting by utilizing the coupled model. When the method is used for solving the vehicle body structure-acoustic coupling problem, relatively good calculation effect can be obtained, and the band frequency width can be analyzed more effectively. Moreover, the method has relatively low quality requirements on the model to reduce the pretreatment time, and has a wide engineering application prospect.

The invention discloses a non-adjacent two phase open-circuit fault-tolerant vector control method for a five-phase permanent magnet embedded fault-tolerant linear motor. The method disclosed by the invention comprises the steps of solving fault-tolerant current of healthy phases by taking that two adjacent phases are equal in current amplitude as a constraint condition according to principles that traveling waves are constant in magnetomotive force before and after a fault and the sum of healthy-phase current is zero, and thus deducing a popularization Clarke transformation matrix of transformation of a natural coordinate system where the healthy phases are located to a two-phase static coordinate system; estimating the healthy-phase counter potential by adopting the transpose of the transformation matrix; and transforming a nonlinear strong-coupling system of the type of motor at a non-adjacent two phase open-circuit fault state into a one-order inertia system by adopting a current internal model controller, a one-order inertia feedforward voltage compensator and a counter potential observer. The method disclosed by the invention suppresses thrust ripples caused by a motor fault. More importantly, the dynamic performance and the steady-state performance are consistent with the performance at a normal state, overshoot-free quick response is realized, and the switching frequency of a voltage source inverter is constant.

The invention discloses a strap down inertial navigation wave measurement method and system. The method comprises the following steps: 1, acquiring moving track data and moving attitude data of a carrier in a three-dimensional space along with waves; 2, performing strap down inertial navigation posture calculation on the moving track data and the moving attitude data, thus obtaining an Euler attitude angle and an attitude matrix of the carrier, and obtaining an acceleration of the carrier under a natural geographical coordinate system according to the attitude matrix; 3, performing twice integration on the acceleration under the natural geographical coordinate system, and obtaining a displacement of the carrier; 4, performing zero-crossing wave statistics according to the displacement of the carrier, and indicating a direction with the maximum occurrence rate to be a main wave direction. According to the strap down inertial navigation wave measurement method, real-time sampling and calculation and outputting of attitude, speed and displacement information can be realized; meanwhile, the real-time observation capacity and the standardization of an instrument are improved, the instrument performance is improved, and the cost, the volume and the mass of the instrument are reduced.

The invention discloses a five-phase permanent magnet embedded fault tolerant linear motor adjacent two-phase open circuit fault tolerant vector control method. Based on the principles that the magnetic motive force of traveling waves remains unchanged before and after a fault occurs and that the non-fault phase current sum stays at zero and taking the equality of the non-adjacent two-phase current amplitude as a constrained condition, the non-fault phase fault tolerant current is obtained to further deduce the generalized Clark transform matrix from the natural coordinate system of the non-fault phase to the two-phase stationary coordinate system. The non-fault opposite potential is observed by the transpose matrix of the transform matrix. A current internal model controller, a first-order inertial feed-forward voltage compensator and a counter-electromotive force observer are used to convert the nonlinear close coupling system of such motor under the condition of an adjacent two-phase open-circuit fault into a first-order inertial system. According to the invention, not only the thrust fluctuation caused by motor failure is restrained, but also more importantly, the dynamic performance and the steady-state performance are consistent with those under a normal condition to realize the fast response to non-overshoot and the stable switching frequency of a voltage source inverter.

The invention relates to a method for observing the radial displacement of a low-speed and zero-speed rotor of a bearingless flux switching motor, wherein an anti-phase high-frequency current is injected into a spatially symmetrical winding; The phase winding voltage of bearingless flux switching motor (BFSM) is used to calculate the high frequency component of the phase winding voltage. Calculating the sum of high frequency components of voltage at two windings with 180 degrees of spatial symmetry; Transforming the sum and amplitude of the high frequency components of the voltage of each pairof winding terminals in a space symmetry in a natural coordinate system to a rectangular alpha beta coordinate; According to the relationship between alpha beta coordinate system voltage and rotor radial displacement deltax, delta y, the rotor radial displacement deltax, deltay is observed. The radial displacement deltax, deltay of the rotor can be fed back to the radial suspension and tangentialrotation control of the rotor to realize the control of the rotor suspended in the stator center. As that manufacture cost of the motor and the controller is not increased, the high-frequency component of the winding voltage of the motor itself is utilized to observe the radial displacement of the rotor.

The invention discloses a method of predicting the fracture azimuth based on shear wave polarization analysis. The method includes the steps of acquiring a converted shear wave of a seismic wave; linearly polarizing according to the propagation law of the converted shear wave in an anisotropic solid medium to obtain a shear wave polarized vector under a natural coordinate system; and orthogonally decomposing quick and slow shear vectors in the shear wave polarized vector under the natural coordinate system along R and T directions with time difference [delta]t, according to the superposition principle of the wave, obtaining a shear wave polarized vector under an observation coordinate system in a seismic record of a shear wave R-direction and T-direction polarized components received respectively along R and T directions, and in a time window of wavelength, putting the shear wave polarized vector under the observation coordinate system in a rectangular region range constituted by four tangent lines with every two lines perpendicular to each other to solve the fracture azimuth. The invention solves the problem of large amount of calculation and great influence of noise in the prior art.

The invention relates to a tooth movement evaluation method under a curve natural coordinate system based on an alveolar bone form and belongs to the technical field of dental orthodontics. An alveolar arch curve is constructed based on the alveolar bone form, the curve natural coordinate system is constructed based on the alveolar arch curve and the alveolar bone form, and then, the coordinates, the amount of movement, and the direction of movement of a tooth are calculated on the basis of the curve natural coordinate system. The invention provides the evaluation method of the movement of the tooth relative to the alveolar bone and having a physiological significance, and the evaluation method is beneficial to more scientific, more reasonable and more accurate tooth movement scheme design and curative effect evaluation.

The present invention provides a driver' front vision measurement system. The driver' front vision measurement system comprises a receiving device, a simulation device and a central controller; the receiving device comprises a light receiving screen and a ground measuring platform, wherein the light receiving screen is used for converting received light signals into electrical signals, and the ground measuring platform is used for measuring the coordinates of a tested vehicle in a natural coordinate system and the angle value of the Z plane of a simulated state coordinate system and the ground; the simulation device comprises a laser emitter, a three-direction guide rail and a motor arranged at the terminal of the three-direction guide rail; and the central controller is used for controlling the receiving device and the simulation device, receiving a scanning result and carrying out calculation and output. According to the driver' front vision measurement system of the invention, based on the conversion of the position coordinates of a V2 point, the ratio of the projection of the V2 point in an s region to the area of the s region is calculated, so that whether any vehicle conforms the national standards can be accurately and quickly judged.

The invention relates to a shear wave birefringence-based fracture attribute factor extraction method. The method includes the following steps that: horizontal component data volumes received by a multi-component detector are received, wherein the horizontal component data volumes include a radial component data volume R (t) and a tangential component data volume T(t); and theta and delta which make normalized cross-correlation and the value sigma (theta and delta) of a function are maximum are adopted as fracture attribute factors, wherein theta is an included angle between a natural coordinate system and an observation coordinate system and indicates a fracture development direction, and delta is delay time between fast shear waves and slow shear waves after fracturing, and indicates crack development density.

The invention relates to the technical field of motion behavior recognition, in particular to an animal motion behavior discrimination method and a device based on time series correlation analysis. The method comprises obtaining the known continuous motion state of the animal, the corresponding three-axis acceleration information and the continuous three-axis acceleration information to be discriminated; converting three-axis acceleration information into three-dimensional data in natural coordinate system, forming training data with three-axis acceleration information of known motion state and corresponding three-dimensional data, forming test data with three-axis acceleration information to be discriminated and corresponding three-dimensional data; according to the temporal correlation between the movement behavior states and the iterative regression tree model trained by the training data, judging the movement behavior states of the test data. By combining with the temporality of behavior state, the method makes up for the shortcomings of iterative decision tree in the processing of highly correlated data, and further improves the accuracy of behavior discrimination.

The invention discloses an efficient wave power generation device under a natural coordinate system. The device comprises three power generation units; each power generation unit comprises an inner buoy and an outer buoy which are arranged in a nested manner; the inner buoy is longer than the outer buoy; coils re arranged in the inner buoy; and the outer buoy is connected with permanent magnets through a support. According to the device, the permanent magnets are mounted on the outer buoy, the coils are mounted on the inner buoy, relative movement of the inner buoy and the outer buoy is realized through fluctuation of waves, induction current is produced in closed coil loops, and wave power generation is realized. The power generation manner is a primary energy conversion manner, and the loss in the secondary energy conversion process in the prior art is reduced, so that the utilization efficiency of wave energy is improved. The X-direction power generation unit, the Y-direction power generation unit and the Z-direction power generation unit are designed according to the principle of permanent-magnetic linear power generators, and the wave energy in the three directions can be utilized simultaneously, so that the power generation power of the device is improved.

The invention discloses an automatic identification system and an automatic identification method for the mounting angle of an early-warning device for vehicle driving. The system comprises a GPS (global positioning system) module, a GSensor module, an MCU (micro controller unit) and a main control processor. The GPS module is used for collecting longitude and latitude, speed and angular separation information of the early-warning device. The GSensor module is used for collecting acceleration magnitudes in three directions on an internal coordinate system therein in real time. The MCU is used for collecting data of the GPS module and the GSensor module in real time and sending the data to the main control processor. The main control processor is used for calculating axis angles of an xyz natural coordinate system in the forward direction of a vehicle according to the received data so as to automatically identify and calibrate the mounting angle of the early warning device. The automatic identification system and the automatic identification method have the advantages that direction data and braking data which are collected by the GPS module and an acceleration sensor are analyzed, and the mounting angle of the early-warning device as well as the axis angles between xyz axes of the acceleration sensor and a vehicle coordinate system are calculated, so that requirements on the mounting angle of the early-warning device are not needed, the early-warning device can be put flat or laterally, and operators operate the early-warning device simply, conveniently and rapidly.

The invention discloses a power frequency electrical parameter extraction method and system and a computer readable storage medium. The power frequency electrical parameter extraction method comprisesthe following steps of acquiring phase information of a three-phase voltage signal, a three-phase current signal and a three-phase voltage on a natural coordinate system of an ultrahigh-voltage DC inversion end AC line at commutation failure moment; converting the three-phase voltage signal and the three-phase current signal on the natural coordinate system to a dq0 coordinate system by a synchronous rotation coordination change method so as to obtain a voltage component and a current component corresponding to each phase on a d axis and a q axis; and obtaining a DC component corresponding toeach phase on the d axis and the q axis, and calculating an apparent power, an active power and a reactive power corresponding to each phase according to the DC component corresponding to each phaseon the d axis and the q axis. By the method, a power frequency component is conveniently and rapidly extracted when commutation is in failure.

The invention discloses a robot posture inverse solution and modeling as well as a resolving method based on shaft invariant and D-H parameters of 1R / 2R / 3R. The method is based on a natural coordinatesystem, and solving the problems that a 1R posture inverse solution based on the shaft invariant and a 2R and 3R posture inverse solution based on the shaft invariant and the D-H parameters, and thecorrectness of the method is verified through CE3 inspector engineering application. The method is characterized in that a succinct representation of a chain symbol system and the shaft invariable isprovided, the function of the pseudo code is achieved, a physical meaning is accurate, and the reliability of engineering implementation is ensured; based on the structural parameter of the shaft invariant, an intermediate coordinate system does not need to be established, measurement errors caused by introduction of the intermediate coordinate system are avoided, and the accuracy of posture inverse solution is guaranteed; and meanwhile, parameterization of the coordinate system, polarity and the structure parameter is realized, so that universality of engineering application is guaranteed.

A method for analyzing an image includes identifying a curved segment of a contour that is associated with noise. The curved segment is smoothed so as to reduce the noise that is associated with the curved segment, thereby providing a smoothed segment. The smoothed segment is transformed to a natural coordinate system, thereby providing a transformed segment. A line is fitted to the transformed segment in order to determine a radius of curvature of the curved segment.

The invention discloses a natural coordinate orientation based active power filter control method, which comprises the following steps: collecting in the real time the power grid side three-phase voltage, the DC bus voltage, the three-phase grid-connected current, the active power filter side three-phase current and the three-phase non-linear load current; calculating respectively the three-phase voltage peak, the active unit components, the power grid side commanded current, and the harmonic compensation commanded current; and accessing the three-phase SPWM modulation signal to drive the active power filter to work and therefore, to achieve the goal of treating harmonic pollution in the power grid. The method of the invention uses the power grid side voltage signal for natural coordinate orientation without the need of coordinate transformation and the traditional phase-lock loop. In addition, in contrast to a traditional harmonic detection method, the method of the invention does not need a low-pass filter, avoiding the influence of system delay. With reduced algorithm complexity, the harmonic compensation of the active power filter to the non-linear load grid-connected current can be achieved, which effectively solves the harmonic pollution problem of the non-linear load to the power grid and provides technical support for its large-scale application.

The invention relates to a method for observing the radial displacement of a rotor of a bearingless flux switching motor based on the sum of space symmetrical winding flux linkage. The method comprises calculating the flux linkage of the phase winding of the bearingless flux switching motor by using the detected voltage and current of the phase winding of the bearingless flux switching motor; calculating the sum of two winding flux linkages with 180 degrees spatial symmetry; Transforming the sum of each pair of winding flux linkages with spatial symmetry in a natural coordinate system to a rectangular [alpha][beta] coordinate; according to the relationship between [alpha][beta] coordinate system flux linkage and rotor radial displacement [detal]x, [detal]y, observing the rotor radial displacement [detal]x, [detal]y is observed. The invention does not increase the manufacturing cost of the motor and the control, the radial displacement of the rotor can be observed by utilizing the winding voltage and the current of the motor and the tangential position angle of the rotor.

The invention discloses a dynamics modeling method of a four-axis mechanical arm. The dynamics modeling method includes: firstly, establishing a natural coordinate system according to the structure ofthe four-axis mechanical arm; defining vector parameters of each axis of the mechanical arm in a natural coordinate system; converting the data into a coordinate form; substituting the coordinate ofeach vector parameter into a Kaien equation to respectively obtain an inertia term equation, a centrifugal term equation and a gravity term equation of each axis, and simplifying the equations; addingthe simplified equations of each axis to obtain a dynamics simplified equation of each axis; establishing the four-axis mechanical arm model according to the kinetic equation of the first axis, the kinetic equation of the second axis and the kinetic equation of the third axis. According to the modeling algorithm adopted by the invention, the particularity of the structure and the working form andposition of the mechanical arm is utilized, so that a large amount of repetitive calculation contents in a traditional method are omitted, the calculation speed is greatly increased, and conditions are provided for high-frequency and accurate dynamic control.

The invention discloses a short-circuit fault-tolerant vector control method of an embedded mixed magnetic material fault-tolerant cylindrical linear motor, which includes establishing a five-phase embedded mixed magnetic material fault-tolerant cylindrical linear motor model; using the non-faulty phase current of the motor to compensate the short-circuit fault phase It leads to the lack of normal thrust of this phase and suppresses the thrust fluctuation caused by the short-circuit current of this phase; the expected phase voltage is obtained by adopting a series of coordinate transformation and voltage feedforward compensation strategies, and the CPWM modulation method based on zero-sequence voltage harmonic injection is used to realize the motor Fault-tolerant vector control after phase short-circuit fault. The invention can not only suppress the thrust fluctuation of the motor under the condition of phase short-circuit fault-tolerant operation, but more importantly, its dynamic performance, steady-state performance and normal performance are consistent, the switching frequency of the voltage source inverter is constant, and the CPU The overhead is small; when any one-phase short-circuit fault occurs, the natural coordinate system only needs to rotate a certain angle counterclockwise to realize fault-tolerant operation of the motor.

The invention provides a cascaded H-bridge converter control method under a power grid harmonic background, and provides an improved unit vector directional direct current control strategy under a natural coordinate system by taking improvement of the control performance of a converter under the power grid harmonic background as a target and taking a single-phase cascaded H-bridge converter as anobject so as to enable the output current power factor to be controllable, and the total harmonic distortion rate of the current to meet the requirements of a power grid. According to the control method, the fundamental frequency component of the power grid is rapidly extracted by using a delay signal cancellation method, and an ideal unit vector under a natural coordinate is solved for orientation, so that an accurate current reference value is obtained, and direct current control is carried out by using a proportional resonance controller with excellent performance, and the influence of theharmonic background on the control system is further eliminated through distortion voltage proportion feedforward.

The invention discloses an improved second-order linear active disturbance rejection permanent magnet synchronous motor control method. The method specifically comprises the following steps: 1) establishing a mathematical model of a permanent magnet synchronous motor under an ABC natural coordinate system; 2) giving a basic formula of coordinate transformation of the permanent magnet synchronous motor; 3) deriving a motor mathematical model under a d-q axis coordinate system; 4) designing a second-order linear active-disturbance-rejection controller of a rotating speed loop and a current loop; 5) designing a first-order linear active disturbance rejection controller of a d-axis current loop; 6) designing an improved second-order linear active-disturbance-rejection controller by adopting a model compensation method on the basis of the traditional second-order linear active-disturbance-rejection controller; 7) performing a comparison simulation experiment on the PMSM under the improved second-order linear active disturbance rejection control and the PMSM under the traditional PID control in MatLab / Simulink, wherein the result proves the correctness and feasibility of the algorithm. According to the embodiment of the invention, in the practical process, the setting number of controller parameters is reduced, the precision of the observer is improved, the robustness of the system is enhanced, and the control performance of the whole permanent magnet synchronous motor speed regulation system is improved.

The invention discloses a multi-shaft robot forward kinematics computing method based on a shaft invariant. A shaft collection is used to describe correspondingly a multi-shaft machine device. Based on a natural system of coordinates, a shaft invariant corresponding to the shaft of the shaft collection is utilized to compute control parameters of the multi-shaft machine device. The invariance property of the shaft invariant is utilized to establish an iterative kinematical equation based on the shaft invariant, symbols of the iterative kinematical equation are corresponding to pseudocodes, andthe topological relation and chain order relation of a kinematic chain of the multi-shaft machine device are reflected by the symbols of the iterative kinematical equation. An iterative forward kinematics numerical value of the kinematic chain is computed. An iterative deviatoric speed based on the shaft invariant is computed. According to the multi-shaft robot forward kinematics computing methodbased on the shaft invariant, by means of a concise kinematic chain symbol system, reliability and mechanized computation of the accomplishment of the system are guaranteed; the method is provided with an iterative based on the shaft invariant, and real-time property of the computation is guaranteed; complete parametric modelling of the coordinate system, polarity and system structure parametersis achieved; and universality of models is guaranteed.

The invention belongs to the related technical field of airplanes, and particularly relates to a control method of an airplane starting and generating integrated motor, which comprises the following steps that S1, in a starting mode, firstly, coordinate change needs to be carried out on current; a current waveform under a natural coordinate system is converted into a synchronous rotating shaft, and error-free adjustment can be realized through a PI controller after a measured value is compared with a reference value; S2, SG transition control comprises control of connection and disconnection of a ground power supply, conversion of a closed-loop control strategy and connection and disconnection of an equipment load switch; and S3, in the generating mode, the maximum direct-current voltage output by the SG is limited by the bus voltage. The invention provides a set of complete control strategy of the airplane starting and generating integrated motor. Therefore, the SG can provide enoughkinetic energy when the airplane engine is started, the safety of transition conversion can be guaranteed, the generating mode can be smoothly switched to, high-quality electric energy is provided forthe whole airplane, and technical support is provided for the application of the starting and generating integrated motor to a multi-electric airplane and a full-electric airplane.

The invention discloses a finite set model prediction current control method of a five-phase permanent magnet synchronous motor, which includes mapping the voltage, current and flux linkage of the five-phase permanent magnet synchronous motor in a natural coordinate system to d1 respectively according to the extended Parker rotation transformation formula ‑q1 and d3‑q3 two orthogonal rotating coordinate systems; reconstruct the input voltage vector control set used in the FCS‑MPCC algorithm; obtain the amplitude of Ui' in the d1‑q1 coordinate system and the components of the virtual vector The action time distribution ratio of the two basic voltage vectors required; constructing the objective function in the FCS-MPCC algorithm of the five-phase permanent magnet synchronous motor; selecting the virtual voltage vector that minimizes the objective function as the control output; the selected virtual voltage vector Pulse sequence generation design and other steps. The invention eliminates the low-order harmonic component of the five-phase motor current caused by the harmonic d3-q3 space, ensures that the algorithm does not require too much calculation, is easy to implement with a digital processor, reduces the difficulty of program design, and reduces the number of digital chips operating power consumption.

The invention relates to the technical field of magnetic flux ropes, in particular to a method for determining the boundary and configuration of an interplanetary magnetic flux rope. The method comprises the following steps: establishing a magnetic cloud natural coordinate system, and determining a magnetic field component expression of a flux rope in the magnetic cloud natural coordinate system;determining a point M which is firstly detected by a satellite in the magnetic cloud and a point N which is closest to a magnetic cloud axis on a satellite orbit; determining a linear equation passingthrough the two points through the coordinates of the M point and the N point; and according to the magnetic field component expression of the flux rope and the linear equation passing through the Mpoint and the N point, obtaining the expression of the magnetic field detected by the satellite passing through the magnetic cloud. The invention provides a novel and simple method for determining themagnetic cloud boundary and the magnetic field configuration. When the method is used for determining the magnetic cloud boundary, the defect that the boundary is not universally determined accordingto magnetic field and plasma characteristics in the prior art is overcome, and meanwhile uncertainty is reduced.

The invention relates to a shear wave birefringence-based fracture attribute factor extraction method. The method includes the following steps that: horizontal component data volumes received by a multi-component detector are received, wherein the horizontal component data volumes include a radial component data volume R (t) and a tangential component data volume T(t); and theta and delta which make normalized cross-correlation and the value sigma (theta and delta) of a function are maximum are adopted as fracture attribute factors, wherein theta is an included angle between a natural coordinate system and an observation coordinate system and indicates a fracture development direction, and delta is delay time between fast shear waves and slow shear waves after fracturing, and indicates crack development density.

The present invention provides a driver' front vision measurement system. The driver' front vision measurement system comprises a receiving device, a simulation device and a central controller; the receiving device comprises a light receiving screen and a ground measuring platform, wherein the light receiving screen is used for converting received light signals into electrical signals, and the ground measuring platform is used for measuring the coordinates of a tested vehicle in a natural coordinate system and the angle value of the Z plane of a simulated state coordinate system and the ground; the simulation device comprises a laser emitter, a three-direction guide rail and a motor arranged at the terminal of the three-direction guide rail; and the central controller is used for controlling the receiving device and the simulation device, receiving a scanning result and carrying out calculation and output. According to the driver' front vision measurement system of the invention, based on the conversion of the position coordinates of a V2 point, the ratio of the projection of the V2 point in an s region to the area of the s region is calculated, so that whether any vehicle conforms the national standards can be accurately and quickly judged.

An axis-invariant-based accurate multi-axis robot structure parameter measurement method, comprising: building a multi-axis robot system, wherein the multi-axis robot system includes a link sequence and a joint sequence, and converting the joint sequence in a tree chain to a corresponding axis sequence and a parent axis sequence thereof, an axis in the axis sequence being a translation axis or a rotation axis; using an axis set to correspondingly describe the multi-axis robot system and taking a natural coordinate system as a basis, wherein a natural joint space takes the natural coordinate system for reference, the origin of the natural coordinate system is located on a joint axis, and the directions of coordinate systems are consistent during system reset; forming a fixed axis invariant by means of an axis invariant and a position vector of the origin on an axis; and using a laser tracker or the other measurement devices to measure measuring points on links, wherein a measurement process is always carried out from a root link to a leaf link in sequence. The accuracy of modeling is ensured.