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258 results about "Axis–angle representation" patented technology

In mathematics, the axis–angle representation of a rotation parameterizes a rotation in a three-dimensional Euclidean space by two quantities: a unit vector e indicating the direction of an axis of rotation, and an angle θ describing the magnitude of the rotation about the axis. Only two numbers, not three, are needed to define the direction of a unit vector e rooted at the origin because the magnitude of e is constrained. For example, the elevation and azimuth angles of e suffice to locate it in any particular Cartesian coordinate frame.

Multiple-loop absolute type rotary encoder based on rotating transformer

The invention relates to a multiturn absolute rotary encoder based on a rotary transformer, which is characterized in that: a sensor is displaced by taking the rotary transformer as a shaft angle; a shaft angle decoding circuit can be formed by adopting DSP as a core processor; a sine wave which can be controlled by frequency and phase in the method that the circuit is synthesized by direct digital frequency for the numerical control of an oscillator; and the sine wave is directly taken as an excitation rotary transformer signal via a power amplifier and a filter circuit; the rotary transformer signal is transferred to A/D converter after being run through a matching circuit of electronic transformer; after sampling, digital filtering and digital signal processing, the sine and cosine value for the actual angle of two channels is generated; the angle error change is tracked dynamically by the PI algorithm; the mechanical displacement of the rotating object is converted into digital shaft angle position and speed. The multiturn absolute rotary encoder based on a rotary transformer has the advantages of high tracking speed, high conversion accuracy, high reliability, simple structure, sensitive movement, low environmental condition, strong anti-interference capability, high measuring accuracy and speed voltage output.
Owner:连云港杰瑞电子有限公司

Angle measurement precision detection apparatus of encoder and detection method thereof

The invention relates to the precision shaft angle measuring instrument precision detection filed, more particularly to an angle measurement precision detection apparatus of an encoder and a detection method thereof. The apparatus comprises a coupling assembly, a precision main shaft, a motor, a precision encoder, a connection base, a rotary table, a workbench, and a computer system. The precision encoder is employed as a reference and is connected with the precision main shaft coaxially. The precision main shaft is driven by the motor; and an output shaft of the precision main shaft is connected with a detected encoder. The computer controls the rotating speed and the position of the motor as well as simultaneously collects angle measurement data of the precision encoder and the detected encoder; and an error value representing deviation of the position output of the detected encoder from the position output of a reference precision encoder is obtained in rotation angles from 0 degree to 360 degrees of the precision main shaft. And processing is carried out by the computer to provide various measurement errors of the detected encoder and error frequency spectrums. According to the invention, beneficial effects are as follows: there are lots of measurement points and measurement can be carried out continuously, so that various errors of a detected encoder can be reflected; a frequency spectrum analysis on an error source can be carried out; automatic measurement is carried out, the measuring period is short and efficiency is high; and electronization of data processing is realized as well as detection data are filed.
Owner:CHANGCHUN INST OF OPTICS FINE MECHANICS & PHYSICS CHINESE ACAD OF SCI

Non-similar dual-redundancy integrated navigation device applied to unmanned plane

The invention discloses a non-similar dual-redundancy integrated navigation device applied to an unmanned plane, comprising main and standby combined navigation systems and a difference data transmission radio, wherein a laser strapdown inertia-satellite combined navigation system is adopted as the main combined navigation system which comprises a laser strapdown inertia navigation part and a satellite receiver; an optical fiber strapdown inertia-satellite combined navigation system is adopted as the standby combined navigation system which comprises an optical fiber strapdown inertia navigation part and a satellite receiver; the satellite receivers are both used for receiving GPS difference information, carrying out difference correction resolving and outputting satellite positioning information; the strapdown inertia navigation parts are both used for receiving atmosphere information and control commands and simultaneously outputting navigation information; the main and standby combination navigation systems transmit respectively received atmosphere information and satellite positioning information via serial interfaces. The device has the advantages of high reliability, good maintenance and lowering of requirements on a power supply caused by volume, weight and cost, providing of plane shaft angular rate information, high navigation precision and practicability.
Owner:BEIHANG UNIV

Open-loop control method for rotation speed change of reaction wheels and unloading method

The invention provides an open-loop control method for the rotation speed change of reaction wheels (hereinafter referred to as flywheels) and an unloading method. The open-loop control method for the rotation speed change of the reaction wheels and the unloading method comprise the following specific steps that 1, controlling is conducted through the four flywheels, and the instruction of the magnitude of the reaction wheel control torque of the fourth flywheel is adjusted to be consistent with the magnitude of the theoretical nominal rotation speed friction torque; 2, a control instruction output by a controller is limited within the maximum output torque, the control torque of each flywheel is distributed according to a flywheel distribution matrix, after the control torque of each flywheel is distributed, the flywheel with the maximum output torque is limited within the maximum torque, and the control torque of the other two flywheels is decreased and increased proportionally; 3, the momentum of a synthetic angle of the four flywheels is calculated, and when any axial angle momentum reaches the unloading threshold range and the relationship between the magnetic field intensity and an angular momentum included angle during unloading is met, magnetic torquers are started to be uninstalled; and 4, the magnetic torquer with the maximum unloading capacity is selected to work, and the flywheels are unloaded by adopting a switch control mode.
Owner:SHANGHAI ENG CENT FOR MICROSATELLITES

Unmanned aerial vehicle-based guided missile attack route planning method

ActiveCN105157488AMeet the requirements of tail smokeReduce the difficulty of manual flight lateral controlSelf-propelled projectilesAxis–angle representationUncrewed vehicle
The invention relates to an unmanned aerial vehicle-based guided missile attack route planning method which comprises the following steps: calculating to obtain the wind speed and the wind direction according to fight parameters of an unmanned aerial vehicle, and determining the sun illumination azimuth angle according to local time; calculating track angles of the unmanned aerial vehicle attacked by guided missiles from the left side and the right side according to the wind speed and the wind direction, and selecting the side having the relatively small absolute value of the difference value between the track angle of the unmanned aerial vehicle and the sun illumination azimuth angle to be used as the side suitable for being attacked by the guided missiles; determining the launching off-axis angles and launching axial distances of the guided missiles according to launching requirements and trajectories of the guided missiles so as to obtain the laterodeviation of the unmanned aerial vehicle; and calculating to obtain the coordinate of laterodeviation point stroke according to the track angle, at the side suitable to be attacked by the guided missiles, of the unmanned aerial vehicle, the laterodeviation of the unmanned aerial vehicle, and known impact point coordinates and further to obtain the attack route of the guided missiles, so that the unmanned aerial vehicle flies for attacking according to the attack route. According to the unmanned aerial vehicle-based guided missile attack route planning method, use requirements of all-weather attack of the unmanned aerial vehicle are met, and the automation degree, the rapidity and the real-time performance of the attack can be improved to the greatest extent.
Owner:CHINA ACAD OF AEROSPACE AERODYNAMICS

Global optimization method for cutter-axis vector based on minimum angular acceleration of machine tool rotating shaft

The invention belongs to the technical field of high-quality and high-efficiency milling of complex curved surface parts, and relates to a global optimization method for a cutter-axis vector based onthe minimum angular acceleration of a machine tool rotating shaft. The method comprises the steps of generating a cutter track by using an equal residual height method according to the curved surfaceand cutter characteristics; establishing an inverse kinematics relation of a five-axis machine tool; converting the cutter-axis vector under the workpiece coordinate system into a rotation angle valueof rotary feeding shaft of the machine tool, calculating the angular speed and the angular acceleration of the rotary feeding shaft of the machine tool by using a finite difference method; calculating a feasible space of the cutter axis at the position of a cutter contact point by means of a C space method according to an interference judgment criterion, judging the concavity and convexity of a cutter path curve, and determining a key cutter-axis vector on the cutter path curve; and optimizing the cutter-axis vector by taking the minimum angular acceleration in each interval as an objective.The method can effectively reduce the angular acceleration of the rotary feeding shaft of the machine tool in the machining process, realize the stability of the machining process, improve the surfacemachining quality and reduce the machining contour error.
Owner:DALIAN UNIV OF TECH
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