71 results about "Acceleration amplitude" patented technology

A Constant Force Control methodology and system utilizing integrated sensors and unique control algorithms to determine required applied force to mitigate shock events in an adaptive energy absorption system, typically comprising of a spring and an adjustable energy absorber or damper element. By utilizing an expected acceleration profile and event duration for an anticipated shock event an acceleration amplitude can be determined from a measure impact velocity. From this and a measured payload mass a system controller can determine the force necessary to be applied by the energy absorber in order to stop the payload over the full desired length of the available energy absorber stroke in order to minimize the forces experienced by the payload.

The invention discloses a low frequency performance calibration platform for an accelerometer, which comprises a mechanical platform body mainly composed of a speed-stabilizing platform and a driven platform. A counter top of the speed-stabilizing platform is parallel to the ground, a rotating shaft of the speed-stabilizing platform is perpendicular to the ground, the driven platform is installed on a platform face of the speed-stabilizing platform, the accelerometer is installed on a platform face of the driven platform, and an input shaft of the accelerometer is parallel to the horizontal surface. The low frequency performance calibration platform for the accelerometer is based on an acceleration simulation rotary table, acceleration amplitude exerted on the accelerometer is determined by angular speed and work radius of the speed stabilizing platform of the rotary table, the driven platform of the rotary platform determines the frequency of acceleration, and calibration of super-low frequency performance of the accelerometer is achieved by controlling low speed rotation of the driven platform.

The invention discloses a traceable calibration method for dynamic characteristics of a high-shock acceleration transducer, and belongs to the technical field of acceleration transducer measurement. The traceable calibration method is as follows: a very narrow pulse is used for exciting the high-shock acceleration transducer on the basis of realizing the traceable calibration under the condition of a broad pulse for the high-shock acceleration transducer to be calibrated to measure a frequency response characteristic of the high-shock acceleration transducer by a test or metrologic instrument and realize the traceable calibration of the dynamic characteristics thereof. A formula of minimum calibration broad pulse width t1 and a formula of maximum narrow excitation pulse width t2 which are required by the traceable calibration are deduced by the traceable calibration method according to different natural frequencies of the high-shock acceleration transducer with higher calibrated natural frequency (above 50kHz) and great acceleration amplitude (up to 2.0*10<5>g). The new technological breakthroughs are meaningful and valuable to the calibration theories and the practical application. The traceable calibration method for the dynamic characteristics of the high-shock acceleration transducer is worthy application and popularization.

Provided is a judgment method for motion state and footwear. The judgment method comprises following steps of: step S10: acquiring pressure amplitude of forefeet and rear feet within the period T, obtaining effective step numbers by calculating steps based on pressure amplitude, respectively defining the numbers as D1 and D3, effectively calculating average value of pressure amplitude and respectively defining the value as M1 and M3, and effectively calculating average value of time of duration for pressure amplitude and respectively defining the value as t1 and t3; step 20: making comparisons among D1, D3, M1, M3, t1, t3 and multiple different preset value in order to determine and acquire motion state. The above judgment method for motion state is less susceptible to interference of other unrelated motion so that high judgment accuracy is obtained. Low algorithm complexity is adopted by the above judgment method for motion state.Moreover, motion state is judged to be more accurate by introducing acceleration amplitude, absolute value of angle amplitude and the feature of maximum value for absolute value of angle amplitude.

The invention relates to an equipment owner identity real-time identification method and device based on an acceleration period change rule. An acceleration sensor is arranged in equipment, and an equipment processor receives data of the acceleration sensor and carries out identity identification. The method specifically comprises the following steps that by means of acceleration projections of the acceleration sensor in the X axis, Y axis and X axis, an acceleration amplitude value of the acceleration sensor is obtained in real time; according to the acceleration amplitude value in the period, the period change rule is calculated through the clustering algorithm, and a focusing area of owner period data points in a multi-dimensional space is determined; three-axis data of the acceleration sensor of the equipment is collected in real time at a preset time interval, a corresponding acceleration amplitude value is calculated, and the identity of the owner is judged according to the focusing area of the owner period data points in the multi-dimensional space. By means of the method and device, continuous real-time identity monitoring can be achieved under the condition that use habits of a user are not interfered too much, and the possibility of counterfeit is reduced, so that the safety is improved, and the method and device have an important guiding significance for information safety.

The invention discloses an inertial technology based and Android phone applied detection and smart alarm method for old people's fall. The method comprises the following steps: reading the data concerning the human body acceleration, the angular acceleration and the geomagnetic field strength measured respectively by the accelerometer, the gyroscope, the magnetometer and other sensors in an Android phone; based on the read data concerning the human body acceleration and the alike, using the inertia technique to calculate and seek the accelerations of ax, ay, az at the human body attitude angles and under a geographic coordinate system like the yaw angle (psi), the pitch angle (theta) and etc.; if az is greater than an acceleration amplitude threshold and the duration is longer than t1, indicating that the human body is in motion; waiting until t2 time, if the yaw angle (psi) or the pitch angle (theta) is greater than an angle threshold, determining a fall occurs; otherwise, considering a normal human movement is taking place; when a fall is detected, starting the smart alarm; and if in the t3 time, the alarm is not cancelled by the old people, sending the alarm information about the position and the body condition of the old people to their relatives and medical institutions. With the invention, it is possible to increase the detection accuracy of falls substantially. The method can also be expanded conveniently.

The invention discloses a high speed railway bridge vehicle-bridge vibration performance safety early warning method. The method includes acquiring the maximum value of the acceleration response amplitude for each passing train and the corresponding vehicle speed data, pairing the corresponding elements of two sets of sequences, and making an arrangement according to the vehicle sped; decomposing the acceleration response amplitude sequences of a main beam by means of wavelet packet decomposition, extracting the acceleration-vehicle speed median line, and determining the optimal wavelet packet decomposition parameters according to the matching degree of the acceleration amplitude mean of the acceleration sequence within the fixed sequence length; acquiring the fluctuation interval, surrounding the acceleration-vehicle speed median line, of the acceleration amplitude in each subsequence based on an interval estimation theory; and superimposing the acceleration fluctuation interval and the acceleration-vehicle speed median line to obtain the safety early warning interval of the high speed railway bridge vehicle-bridge vibration performance. Compared with the prior art, the method provided has the advantages of comprehensive consideration of factors, accurate and reasonable way, clear physical meaning, easy understanding and implementation, and wide application.

The invention provides a numerical simulation analysis method for dynamic stiffness of a loudspeaker basin stand. The method comprises the steps of firstly building a finite element simulation model comprising the sub-steps of 1, adding a physical field and a research type; 2, building a geometrical model of the loudspeaker basin stand; and 3, setting the physical field; setting an elastic material model, damping, a constraint condition and a loading force in a solid mechanics physical field; 3, setting a material parameter; and 4, setting grid types and sizes, and dividing grids to generate afinite element model; then solving the finite element model by using a frequency domain analysis method; and at last, performing postprocessing to acquire a change relationship of the dynamic stiffness of the loudspeaker basin stand along with frequency. A distribution diagram of the stress, strain and displacement on the basin stand and frequency responses of the displacement amplitude, speed amplitude and acceleration amplitude of any point on the basin stand also can be acquired under the sinusoidal loading effect at any frequency.

The invention relates to a method for recognizing a torsion mode and a bending mode in a mode test. The method is characterized by comprising the following steps that (1) a plurality of contour points are symmetrically arranged at the positions, with relatively high vehicle body frame structure rigidity, on the left side and the right side of a vehicle TB needing to be tested; (2) excitation is applied to the position, with large rigidity, of the lower end, at the combined part of the right side of the vehicle body and a firewall, of a front longitudinal beam through a multi-point excitation and multi-point response method, a frequency and acceleration Z-direction amplitude curve is obtained, and a mode shape result is obtained; (3) the curve is processed, the acceleration amplitude mean curves on the left side and the right side are added or subtracted, averaging is conducted, and thus a resultant acceleration mean value curve and a difference value acceleration mean value curve are obtained; (4) the mode shape result is combined, and corresponding modes are recognized when peak values simultaneously appear in the resultant acceleration mean value curve and the difference value acceleration mean value curve. The problem that the torsion mode and the bending mode in numerous mode shapes are difficult to recognize in existing TB mode tests is solved. The efficiency and the accuracy of mode judgment are improved.

The invention discloses a suspension system of an electric vehicle. The system comprises a suspension structure, an acceleration detection device, a calculation device and a control device; the suspension structure comprises an outer support frame and an inner support frame, an excitation coil and a magnetic movable member; the outer support frame is connected to a body of the electric vehicle; the inner support frame is connected with a power assembly; an elastic member is installed between the outer support frame and the inner support frame; the magnetic movable member is positioned inside the excitation coil and is connected to the inner support frame; the acceleration detection device detects acceleration signals which are vertical to the ground of the power assembly; the calculation device calculates the acceleration amplitude based on the acceleration signals and calculates the difference between the acceleration amplitude and a amplitude threshold; the control device controls the energizing direction and the energizing current of the excitation coil according to the direction of the acceleration signals, the difference between the acceleration amplitude and the amplitude threshold. The electric vehicle suspension system can effectively reduce the vibration on the powertrain caused by the excitation of road surface. The invention also discloses a suspension structure, anelectric vehicle and a vibration damping control method thereof.

The invention provides an acceleration amplitude online calibration system of a laser vibration system in a high temperature condition. The system comprises a standard vibrating device used for generating and outputting a standard sine vibration signal and calculating an acceleration of the standard sine vibration signal, a quartz lamp array used for placing and heating a standard test piece, a ceramic rod used for transmitting the standard sine vibration signal to the standard test piece and isolating the standard vibrating device and the quartz lamp array, and a laser polarization system used for testing an acceleration signal of the standard test piece, one end of the ceramic rod is connected with the standard vibrating device, and the other end of the ceramic rod is connected with thequartz lamp array. According to the system, the problem of transmission of the acceleration amplitude output by the standard vibrating device to a high temperature environment without loss is solved,the operating environment of a standard accelerometer is guaranteed to be in a normal temperature or a controllable state, and the metering guarantee requirement of a thermal modal test of an ultrasonic velocity air defense missile flat type thermal modal test system is met.

The invention relates to a method for controlling vehicle components to move, in particular to a method for controlling a first vehicle component to move relative to a second vehicle component. The method comprises the following steps of determining receiving force on the second vehicle component, wherein the force is caused by accelerated movement of the first vehicle component in the running period; determining an acceleration amplitude of the first vehicle component to enable the receiving force on the first vehicle component not to be exceeded; and controlling the first vehicle component to accelerate according to the determined acceleration.

The invention discloses a driving comfort evaluation method, and the method comprises the following steps: S1, determining a vibration direction; S2, determining the intensity of the vibration in eachvibration direction: wherein the vibration intensity is expressed by an acceleration root-mean-square value, and the unit is m/s2, S3, adopting a 1/3 octave method to carry out spectral analysis on the vibration signal with the 1/3 octave center frequency, and obtaining an evaluation index; and S4, giving different vibration limit values according to different vibration time. According to the invention, the acceleration root-mean-square value is converted from the time domain to the frequency domain for spectral analysis so that the acceleration amplitude is associated with the frequency, andthe evaluation result is more real and reliable.

The invention discloses a vibration suppression method for a stopping process section of an industrial robot. From the perspective of a signal system, each joint end is directly planned, and a discrete Fourier transform amplitude range of a designed trajectory is taken as a objective function to enable a ratio of amplitude of main resonance frequency of each specific joint end in a planned deceleration section trajectory to be the smallest. Meanwhile, the objective function is made to meet the constraint conditions of ensuring the second-order continuity of the trajectory (c2) and ensuring themonotonicity of speed and the maximum acceleration amplitude limiting, finally, trajectory parameters are obtained by a method of convex optimization, and then the stop motion is completed by real-time interpolation. According to the vibration suppression method, an acceleration trajectory of each joint is directly optimized, so that the ratio of amplitude near a resonance point in a frequency domain is minimized, and then active vibration suppression is realized; and meanwhile, the method can reduce the delay caused by the inverse solution of calculation load, the time lag caused by shapingor notching is avoided, the preset stop time machine running distance is strictly guaranteed, and the safety of personnel and equipment is ensured.

A method for extracting parameters of a piezoelectric multi-wafer equivalent circuit model includes such steps as fixing one end of a piezoelectric multi-wafer on a vibration source, making the otherend free, keeping constant sinusoidal vibration acceleration amplitude a, and obtaining the relation curve between output voltage and vibration frequency of the piezoelectric multi-wafer under different load resistances RL through frequency sweeping. The short-circuit resonance frequency fsc, open-circuit resonance frequency foc, static capacitance Cmc, mechanical quality factor Qoc, maximum powervalue Popt and short-circuit resonance voltage VML (omega sc) are determined. The equivalent inductance Lm, the equivalent capacitance Cm, the equivalent resistance Rm, the equivalent input stress VF, the piezoelectric coupling coefficient A and the static capacitance Cmc are obtained. The invention can accurately describe the relationship between the output voltage characteristic of the piezoelectric multi-wafer and the load, the ambient vibration frequency and the acceleration, and the electric measuring instrument required for the measurement is low in cost.

A method of early recognition of damage in a motor vehicle transmission which comprises at least one acceleration sensor, with which mechanical vibrations in the motor vehicle transmission are detected and converted into an electrical signal. The electrical signal is then digitalized and thereafter carrying our a comparison with a comparison parameter. The mechanical vibrations are detected at defined operating points of the motor vehicle transmission and, from the digitalized electrical signal acceleration amplitudes, are determined over a time interval. A count is taken of conditions in which the acceleration amplitudes exceed the comparison parameter and, with reference to the number of such conditions, a calculated probability of damage in the motor vehicle transmission is determined. A motor vehicle transmission whose damage can be determined by the method, and a computer program product for carrying out the individual process steps are also proposed.