14 results about "Transverse velocity" patented technology

The invention relates to a method and system for measuring the lateral velocity of a target based on composite modulation of polarization and orbital angular momentum, and belongs to the field of laser velocity measurement. The invention aims to solve the problem that existing laser lateral velocity measurement methods and technologies cannot accurately measure the lateral velocity of a moving target in atmospheric turbulence and determine the direction of the velocity. The method of the invention comprises the following steps: S1. Modulating a laser signal to generate a dual-mode vortex beam with 1st and 4th order superposition, compositely modulating the laser signal with polarization and orbital angular momentum with a Gaussian beam to generate a modulation signal, and irradiating the target object with atmospheric turbulence to generate an echo signal; S2. Using a wavefront sensor to obtain the distorted phase of the polarization component of the Gaussian beam, generating a compensation phase to perform phase correction on the dual-mode vortex beam; S3. Using an array detector to detect the polarization component of the dual-mode vortex beam after phase compensation correction, the polarization component of the dual-mode vortex beam is used to obtain three lateral Doppler effect spot areas of the echo light field, which are then detected and calculated by the array detector to determine the magnitude and direction of the lateral velocity of the moving target.

The invention discloses a hypersonic flow field density and speed high-precision prediction method, system and device based on physical information constraint U-Net, and a medium. The method comprises the following steps: obtaining value distribution of instantaneous transverse and longitudinal speeds and densities in target wake flow fields with different Mach numbers; forming a data set by the densities, the transverse speeds and the longitudinal speeds of two continuous moments and the density, the transverse speed and the longitudinal speed of the third moment in the target wake flow field at different moments, and dividing the data set into a training set and a test set; constructing a physical information U-Net flow field prediction model, and defining a continuity equation in an N-S equation as a loss function of the model; training the physical information U-Net flow field prediction model to obtain a physical information U-Net flow field prediction model of which the weight is trained; predicting input data by using the physical information U-Net flow field prediction model of which the weight is trained, and obtaining a prediction result through recursive prediction; the system, the equipment and the medium are used for implementing the method. By means of the method, the output data can meet the physical mechanism, and the accuracy is high.

The invention discloses an obstacle cut-in intention prediction method and a vehicle, and the method comprises the steps: judging whether there is an obstacle meeting the initial condition of pre-cut-in in the current environment or not during the operation of the vehicle, and obtaining the historical track of the obstacle if there is the obstacle; according to the historical track, judging whether the obstacle has a lane line attaching trend or not; if yes, the transverse speed weight and the transverse position weight of the obstacle are obtained; and predicting a pre-cut-in intention of the obstacle according to the transverse position weight and the transverse speed weight. According to the method, the slow pre-cut-in intention of the obstacles around the vehicle can be accurately predicted.

The invention discloses a time migration method for a three-dimensional pre-stack wave equation in an imaging ray domain, which relates to the technical field of exploration geophysics and comprises the following steps of: deducing a bidirectional acoustic wave equation in an imaging ray coordinate system based on a Riemann wave field extrapolation theory in a three-dimensional semi-orthogonal coordinate system; an equation is directly solved by adopting a finite difference method, extrapolation of a seismic source and a receiving end wave field is achieved, and errors caused by Green function approximation in a traditional migration method are avoided; and generating a pre-stack time migration result by applying a zero-lag cross-correlation imaging condition. Through first-order linear disturbance approximation, an accurate three-dimensional time-depth conversion partial differential equation set is simplified into an optimized layer stripping algorithm, and a corresponding equation suitable for a weak transverse velocity change medium is deduced. According to the invention, the working process of three-dimensional wave equation time migration is realized in an imaging ray coordinate system, and an accurate seismic imaging result is generated; two-dimensional plane hypothesis limitation is avoided, and high-precision imaging technical guarantee is provided for seismic data processing of a complex structure area.

A numerical control machining trajectory smoothing optimization and interpolation method and device, the method comprises the following steps: obtaining N points to be smoothed based on a plurality of original tool position points preset by a numerical control machine tool, generating a transition curve C n (τ) at each point to be smoothed based on a cubic B-spline method, obtaining the speed upper limit of each transition curve at the maximum curvature point, splicing all straight tool paths and N transition curves into a hybrid tool trajectory, using a forward and reverse speed extreme value scanning method and a 7-section S-type speed planning method to plan the speed under the constraint of N speed upper limits, obtaining an acceleration continuous speed curve, performing interpolation calculation on the hybrid trajectory according to the speed curve, solving dτ by using a 4th-order explicit Adams method of the modified prediction-correction mode in each interpolation period, and obtaining an interpolation point by bringing the curve parameter value τ into C n (τ), the speed planning considers the consistency of the transverse speed, the interpolation method is high in efficiency and accuracy, and the numerical control machining efficiency is improved while the numerical control machining quality is ensured.

The application discloses a global finite time ship trajectory tracking control method considering input and output limitations, S1: a mathematical model of an underactuated ship is established; S2: a trajectory tracking error is obtained based on an actual trajectory and an expected trajectory, a new error is obtained by limiting the trajectory tracking error, and an expected longitudinal velocity and an expected transverse velocity are designed based on the new error; S3: a first finite time sliding mode surface and a second finite time sliding mode surface are designed; S4: a longitudinal control force and a bow shaking control moment are designed; S5: the finite time sliding mode surface is adjusted to convergence through the longitudinal control force and the bow shaking control moment, and then the trajectory tracking error is converged, and finally, the ship trajectory tracking is realized. Under the condition of considering input limitation, the mathematical model of the underactuated ship is established, under the condition of considering output limitation, the trajectory tracking error is limited, so that the transient and steady state performances are ensured, the sailing trajectory is within the preset range, and the ship sailing safety is ensured.

The invention discloses an under-actuated ship trajectory tracking adaptive super-spiral sliding mode control method and system, and the method comprises the steps: obtaining an under-actuated ship motion mathematical model to obtain a tracking error, and constructing a longitudinal virtual control law and a transverse virtual control law; designing a longitudinal adaptive anti-interference sliding mode surface and a longitudinal adaptive law according to the longitudinal speed error, and constructing a ship longitudinal thrust control law by introducing a superhelix algorithm; and designing a transverse self-adaptive anti-interference sliding mode surface and a transverse self-adaptive law according to the transverse speed error, and constructing a ship steering torque control law by introducing a super-spiral algorithm, thereby realizing under-actuated ship trajectory tracking self-adaptive super-spiral sliding mode control. The problems that an effective safety mechanism for observing and compensating environmental interference in real time is lacked in current ship trajectory tracking control research, the system response speed cannot be effectively improved, meanwhile, equipment abrasion cannot be effectively relieved, and an integrated intelligent control module is lacked to relieve the operation burden of sailors are solved.

The present application relates to the technical field of ship motion, in particular to a ship maneuvering motion trajectory prediction method and system fusing shipborne radar wave measurement, the method comprising: acquiring multi-modal data, and preprocessing the acquired multi-modal data; performing multi-modal feature extraction on the preprocessed multi-modal data; performing cross-modal fusion based on the extracted multi-modal features to obtain a fusion feature vector; constructing a feedforward neural network with the fusion feature vector as input, and outputting a prediction value of a ship motion state; performing parameter optimization based on the constructed feedforward neural network, verifying the prediction result output by the feedforward neural network, and outputting a final prediction result; and the final output of the present application, the prediction value of the ship motion state, covers key parameters such as longitudinal velocity, transverse velocity, and yaw angle velocity, providing an accurate basis for ship maneuvering decision-making, and helping to improve the safety and precision of ship navigation.

The present invention provides a motion state estimation method and motion state estimation device that can improve the accuracy of estimating the motion state of an object moving in a direction intersecting the direction of travel of a vehicle. [Solution] From an image captured by the vehicle V1's imaging device 11, objects present around the vehicle V1 are detected. A first estimation model, in which the initial velocity is primarily composed of the vehicle V1's lateral velocity in the width direction, and a second estimation model, in which the initial velocity is primarily composed of the vehicle V1's longitudinal velocity in the direction of travel, are applied to the detected objects. The movement state of the objects is then estimated based on the first likelihood, which represents the movement state of the object, determined by the first estimation model, and the second likelihood, which represents the movement state of the object, determined by the second estimation model.

This invention relates to the field of unmanned vessel berthing and unberthing technology, specifically a fuzzy control method and system for the safe and autonomous berthing and unberthing of unmanned vessels, comprising the following steps: real-time scanning of the surrounding environment using a 3D lidar mounted on the unmanned vessel to generate point cloud data; and determining the desired longitudinal velocity u of the unmanned vessel's vector motion based on the relative pose. d Desired lateral velocity v d and desired turning angular velocity r d The system error and error change rate are input into a fuzzy controller for fuzzification. The control output is decomposed into thrust commands for each thruster of the unmanned surface vessel (USV), controlling the USV to achieve coordinated longitudinal, lateral, and bow-turning movements, enabling the USV to autonomously berth and unberth in an attitude parallel to the shore. This invention significantly improves the control accuracy and adaptability of USVs in autonomous berthing and unberthing under complex sea conditions by introducing a fuzzy adaptive PID control strategy combined with environmental perception and real-time pose calculation using 3D lidar.

The invention discloses an under-actuated ship trajectory tracking fixed time fault-tolerant control method under output constraint. The method comprises the following steps: constructing a fixed time sliding mode fault observer; constructing a virtual control law of preset time performance based on a fixed time preset performance function according to the under-actuated ship mathematical identification model; defining a transverse speed error and a longitudinal speed error according to the virtual control law in combination with a fixed time sliding mode fault observer so as to construct a saturation compensator for compensating dead zone saturation influence of an actuator, and constructing a fixed time integral sliding mode reaching law according to the saturation compensator so as to design a steering engine control law corresponding to a longitudinal propulsion and yawing channel of a ship, and according to the steering engine control law, realizing fault-tolerant control of the under-actuated ship trajectory tracking fixed time under the output constraint. According to the method, the problems that an existing method cannot process executor constraint and fault influence at the same time and cannot adapt to sudden disturbance change, uncertainty and the like are solved, and the safety and engineering realizability of the under-actuated ship under the complex working condition are reduced.

The invention discloses a method for realizing ship bow and stern vectors by a Beidou high-precision positioning technology, which comprises the following steps of: acquiring coordinates at the bow and stern ends of a ship in real time through a Beidou No.3 high-precision positioning module, calculating an included angle between the bow and stern directions and the true north, and decomposing the central point speed of the ship into forward and transverse speeds; and finally, bow and stern directions and velocity vectors are displayed on the electronic chart. According to the method, high-precision bow and stern azimuth measurement can be provided, the error range is + / -0.0015-0.006 degrees, the ship navigation situation is visually presented, the driving safety and efficiency are improved, and the method is suitable for berthing, narrow navigation channels and other scenes.

The invention relates to the technical field of geophysical exploration, and particularly discloses a one-way wave pre-stack depth migration method and system suitable for any variable-speed medium. According to the method, a Helmholtz operator is converted to a wavenumber domain, a square root of the Helmholtz operator is calculated by using a complex number transformation principle, and a propagation operator is efficiently solved in combination with complex number Pade approximation, so that a matrix decomposition operation with high cost in a traditional method is avoided; the system integrates the parallel computing capability of the GPU, realizes efficient processing of wave field extrapolation and imaging, and finally generates a depth migration imaging result. According to the method, the imaging precision and amplitude fidelity in a steep dip structure and a strong transverse velocity change medium are remarkably improved while high calculation efficiency is kept, and the method is suitable for seismic data imaging in a complex geological environment.

The invention provides a multi-control-surface hovercraft docking motion control and simulation method, a program, equipment and a storage medium. The method comprises the following steps: firstly, establishing a four-air-chamber hover dynamic model according to structural characteristics of a hover hover system, and constructing a complete six-degree-of-freedom motion model in combination with resistance change in a docking process; aiming at the problem of weak steering effect during low-speed docking, a method for controlling a heading angle through a screw pitch difference of a propeller is designed; and meanwhile, stability augmentation control is implemented in the sideslip direction, so that the expected transverse speed is zero in the hovercraft docking process. On the basis, a docking motion control simulation platform is built for verification. Simulation results show that according to the control method, the navigational speed error is not larger than one section, the heading error is not larger than 2 degrees, the transverse speed is effectively restrained, high control precision is achieved, and the docking working condition requirement is met. The research has an important guiding value for deeply developing a hovercraft docking driving control system and a docking control technology in a complex environment.