51results about How to "Improve displacement measurement accuracy" patented technology

The single -shaft micro tensile test piece to test the film dynamic performance includes the U shpe supporting platform, movable platform, the snake supporting spring, centring marker, displacement marker. The snake supporting spring is connected with the U shape supporting platform and movable platform; the U shape supporting platform and movable platform are connected with two suspended ends of the film sample; the centring marker is on the top of the movable platform; the displacement marker is pasted to the tail to movable platform and near to the film sample. Compared to the present test piece, the process is available, it has good repeatability and high yield; also it has avoided the test error generated by the supporting girder deformation in tension process. The test piece of invention is proper for the film micro dynamic performance test of single metal, alloy and compound material.

The invention relates to a damping tester of three-point bended beam large-scale material, which can solve the problem of present device that can not test the damping property of large-scale material. Wherein, two ends of three-point bended beam (5-2) are fixed on each hinge base of base; each hinge base is vertically fixed via press beam (5-3); the middle part of three-point bended beam (5-2) is fixed with a load head; the force sensor (4-1) is connected to the load head, the actuator (3-3) and the charge amplifier (4-3); the power amplifier (3-2) is connected to the actuator (3-3) and the signal generator (3-1); the displacement sensor (4-2) is connected to the voltage amplifier (4-4); the charge amplifier (4-3) and the voltage amplifier (4-4) are connected to the data collector (4-5). The invention can complete the damping test of large-scale material.

A displacement gauge comprises an objective lens 15 that projects light onto a measurement subject 16, an exciting portion that vibrates the objective lens 15 at a preset amplitude along an optical axis direction of light passing through the objective lens 15, a position detector for detecting the position of the objective lens 15, an objective lens scan portion 52 for scanning the objective lens 15 along a plane orthogonal to the optical axis direction, an objective lens movement detecting portion 53 for detecting the moved position of the objective lens 15, an operation processing portion 58 for calculating a distribution of displacement amount within a measuring area, based on the positional information of the objective lens 15 within the measuring area detected by the objective lens movement detecting portion 53, and the displacement amounts measured at plural measuring points, and an output portion 66 for outputting the result of calculation by the operation processing portion 58.

The invention relates to an experimental device and method for simulating scouring and vortex-induced vibration of a flexible pipeline. The experimental device comprises a circulating water tank, a support frame, a pipeline model, a universal joint, a water tank wall, a high-speed camera, a laser displacement sensor, fiber bragg grating strain sensors, measuring probes, a guide plate, a tension meter, weights, a moving rail, pulleys, a hanging beam, a multi-beam echosounder, an ultrasonic current meter ADV, a sliding rail and a fixed rail; a plurality of measuring probes are installed at the bottom of the pipeline model, strain measuring points are determined on the surface of the pipeline model at equal intervals along the axial direction, each strain measuring point is equipped with a left fiber bragg grating strain sensor and a right fiber bragg grating strain sensor in the circulating water tank along the water flow direction, and the left and right fiber bragg grating strain sensors are symmetrically arranged on the horizontal outer surface of the pipeline model; one end of the sliding rail is connected with the pipeline model, the other end of the sliding rail is connected with a steel wire rope, and the sliding rail can slide back and forth relative to the support. The device and the method can be used for research of the flexible pipeline and local scouring extension and measurement of the vortex-induced vibration frequency, the amplitude and the pipeline strain.

The invention provides a displacement measurement method based on piezoelectric ceramic open-loop modulation, belonging to the technical field of measurement. The displacement measurement method provided by the invention is characterized by comprising the following steps of: applying a periodic triangular wave driving voltage to piezoelectric ceramic to enable the piezoelectric ceramic to reciprocate; respectively finding out reference positions corresponding to a certain length of the piezoelectric ceramic in opposite movement directions and obtaining driving voltages corresponding to the reference positions; and calculating an average value of the driving voltages; and calculating a displacement amount to be detected by multiplying the change of the average value by gradients of middle section areas, which are close to be linear, in an average value curve of a displacement-driving voltage curve in the process of raising the driving voltages and a displacement-driving voltage curve in the process of decreasing the driving voltages under the driving of the periodic triangular wave driving voltage. The method provided by the invention has the advantages of effectively improving the hysteresis and the non-linearity of the piezoelectric ceramic and improving the precision of the displacement measurement; the displacement measurement can be realized by only carrying out open-loop control on the piezoelectric ceramic, so that the system complexity and the cost are not increased, the method is convenient to combine with other displacement measurement methods and the large-scale high-precision displacement measurement can be realized.

The invention discloses a displacement sensor or an acceleration sensor, belongs to the technical field of fiber sensors, and is characterized in that the displacement sensor or the acceleration sensor comprises a first fiber laser, a cantilever beam and a first platform, wherein, the first fiber laser is clamped between the surfaces of the cantilever beam and the first platform; the first fiber laser and the first platform are arranged below or above the cantilever beam; and the deformation generated by the cantilever beam generates acting force to the first fiber laser. The invention has the effects and benefits that the sensor overcomes the defect that the conventional electrical sensor is liable to electromagnetic interference; and the invention provides the fiber displacement sensor or the fiber acceleration sensor having the advantages of high sensitivity, large measurement range, simple structure, low demodulation cost and better signal-to-noise ratio.

An illumination configuration for imaging-type optical encoders is provided. The illumination configuration generates uniform brightness images of scales and two-dimensional structures when utilizing telecentric imaging optics in the encoder readhead. In one embodiment, a desirable uniform irradiance distribution is created across the field of view by illuminating with a collimated or quasi-collimated beam, but insuring that the illumination is sufficiently incoherent that potential self-images arising from periodic structures on the scale are suppressed. In one embodiment, the ratio of an effective emitter size to a focal length of the collimating lens falls within a selected range, so as to assure relatively uniform illumination across the field of view and still provide sufficiently incoherent illumination. In another embodiment, a diffuser is placed over the collimating lens, which assists in producing uniform illumination even when the direction of illumination varies relative to the scale due to misalignment between the readhead and the scale surface.

A shearing large-size material damping testing device relates to a device for testing damping property of large-size material used in civil engineering, the invention is aimed to resolve the problem that shear damping characteristic of large-size materials used in the civil engineering can not be tested. The two input ends of a piezoelectric force sensor (5) are connected with the output ends of a load head(10) and a electromagnetic vibration exciter (3).The top of the electromagnetic vibration exciter (3) is provided with a laser displacement sensor (7 ).The output end of the piezoelectric force sensor (5) is connected with the input end of a charge amplifier (6).The two input ends of a voltage amplifier (8) are connected with the output ends of the laser displacement sensor (7)and the charge amplifier (6) .The two output ends of the voltage amplifier (8) are connected with the two input ends of a computer data collector (9) .The input end of the electromagnetic vibration exciter(3) is connected with a signal generator ( 1) through a power amplifier (2) . A base (14) is connected with a fixed external member (21). The present invention can test the damping property and the elastic modulus of large-sized materials under shearing effect.

The invention discloses a novel small measuring range ultrahigh precision displacement sensor and a measuring method. The sensor comprises a laser beam, two reflectors, a photoelectric detector, and a processing system. According to the sensor, the laser beam is reflected continuously between the two reflectors which are paralleled arranged, and finally the laser beam irradiates at one position of the photoelectric detector; then the space between the two reflectors is changed and therefore the reflecting path of the laser beam is changed so that the laser beam irradiates at another position of the photoelectric detector. The processing system obtains a detection distance value through processing according to the two different positions, wherein the detection distance value is far more than the real change value of the space between the two reflectors; the processing system can calculate the real change value of the space between the two reflectors through the detection distance value. The sensor having a simple structure, reliable measurement and high precision can be applied in measuring continuous displacement change of objects and is easy for batch manufacture.

The invention discloses an incremental type small-measurement-range displacement sensor and a measurement method. The sensor comprises a laser beam, two reflection mirrors, a distributed type photoelectric detector and a processing system. With the adoption of the sensor, the laser beam is reflected continuously between one group of the two reflection mirrors which are arranged in parallel, and is finally illuminated to the distributed type photoelectric detector, so that the distance between the two reflection mirrors is changed, and a reflection path of the laser beam can be changed; a detection part I, a detection part II and a detection part III on the distributed type photoelectric detector are used for inducing the laser beam for three times, and the processing system is used for processing according to the number of times of receiving the laser beam by detection parts and the distance between the detection parts to obtain a detection value; the detection value is larger than a real change value of the distance between the two reflection mirrors; and the processing system can be used for calculating the real change value of the distance between the two reflection mirrors through the detection value. The sensor is simple in structure and is applicable to measurement of displacement changes of an object to be detected; and the sensor can be used for reliably measuring and has relatively high precision, and can be easily manufactured in a large batch.

The invention discloses a machining device for manufacturing an absolute type steel belt grating ruler, and belongs to the field of industry machining. The shortcoming that a traditional exposure device cannot manufacture the absolute type steel belt grating ruler with double code channels with a cycle and without a cycle is overcome. Displacement measurement accuracy is improved. Manufacturing of an overlength measuring steel belt ruler is achieved. The machining device comprises projection exposure heads, a charge coupled device (CCD) detector and a laser marking device. The two projection exposure heads respectively expose half of the width of a steel belt. The laser marking device is placed below a starting end of an exposure region of the steel belt. The CCD detector is placed below a finishing end of the exposure region of the steel belt. Control output ends of the CCD detector and the laser marking device are connected with a computer. The two projection exposure heads are used for respectively generating strip patterns of the code channels with the cycle and without the cycle, which is needed by the absolute type grating ruler, manufacturing of the absolute type grating ruler with code channels is achieved, and a laser interferometer is used for controlling micro displacement change and improving accuracy.

The invention discloses a monocular vision-based hoisting steel wire rope spatial vibration measurement method, which mainly comprises the following steps: respectively installing a camera and a background screen in front of and behind a vertical steel wire rope to acquire a steel wire rope vibration image sequence; performing noise reduction processing on the acquired image; determining the positions of two edge lines of the steel wire rope in each frame of image by utilizing an edge detection and positioning algorithm; adding a virtual reference line perpendicular to the steel wire rope at the measuring point; calculating coordinates of an intersection point between the reference line and the two edge lines, then calculating a proportionality coefficient between the actual width and thepixel width of the steel wire rope, and then calculating the vibration displacement of the steel wire rope in the first direction; determining a function relationship between the vertical distance between the camera and the steel wire rope and the pixel width of the steel wire rope by utilizing a fitting method, and further calculating to obtain the vibration displacement of the steel wire rope inthe direction vertical to the first direction. According to the invention, the monocular vision device is used for measuring the vibration displacement of the steel wire rope in two directions, so that the measurement cost is reduced.

The invention discloses a novel symmetric small measurement range displacement sensor and a measuring method. The sensor comprises a laser beam, a fixed reflecting mirror, a movable reflecting mirror, a double mirror, a photoelectric detector and a processing system. By applying the sensor, the laser beam is divided into two beams which are respectively reflected to one position on the photoelectric detector at a corresponding side, the space between the fixed reflecting mirror and the movable reflecting mirror is changed, then a reflection path of the laser beam can be changed, the laser beam is finally irradiated to another position of the corresponding photoelectric detector, the processing system calculates according to the two groups of two different positions and obtains two detection distance values which are much larger than real change value of the space between the fixed reflecting mirror and the movable reflecting mirror, and the processing system can calculate the real change value of the space between the fixed reflecting mirror and the movable reflecting mirror according to the average value of the two detection distance values. The sensor disclosed by the invention is simple in structure, applicable to measurement when displacement of an object is continuously changed, reliable in measurement and relatively high in accuracy, and batch manufacturing can be easily realized.

The invention relates to the high precision displacement measurement technical field, and more specifically relates to a high precision prism displacement measuring method based on a digital phase lock; the device does not need a wave-plate; a piezoelectric ceramics driver is added on a reference reflector so as to carry out sine modulation; the phase lock can amplify one time frequency and two time frequency signals, thus realizing high precision and high sensitivity measurement of displacement, and eliminating influences on measurements by background noises and laser intensity fluctuations;the method does not need to know a zero light path difference point and interpolation, only gathers PEM modulation interference signals for a time length (see description), and has nothing to do witha sampling start point and a finish point; the method uses the phase lock amplification technology to improve the displacement precision, can phase lock one time frequency signal and two time frequency signal amplitudes, and divides to eliminate the displacement measuring precision reduction problems caused by laser light intensity fluctuations; the displacement form is arc tangent, thus ensuringthe same linear sensitivity, and eliminating the low sensitivity problem of certain positions of a conventional sine and cosine.

The invention discloses a translational gravity/acceleration measuring sensitive structure, which comprises a frame, a sampling mass cylinder, a variable-spacing capacitive displacement sensor and a reed group, and is characterized in that the sampling mass cylinder is connected with the variable-spacing capacitive displacement sensor; and one end of each reed group is in insulated connection with the side wall of the sampling mass cylinder, and the other end is in insulated connection with the inner wall of the frame. An upper acceleration compensation coil and a lower acceleration compensation coil which are connected in series, and an upper acceleration measuring coil and a lower acceleration measuring coil which are connected in series are respectively arranged outside the upper end and the lower end of the sampling mass cylinder. According to the invention, the deflection motion mode of the sampling mass cylinder is eliminated in principle, and the translational motion of the sampling mass cylinder in the measuring process is realized; the displacement measuring precision is improved; and the heat dissipation area of the coil is increased, assembling is easy, and the size is obviously reduced.