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

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.

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 novel alternative incremental sensor for measuring the micrometric displacement. The novel alternative incremental sensor comprises a laser beam, a fixed reflecting mirror, a movable reflecting mirror, a detection reflecting mirror, a photoelectric detector I, a photoelectric detector II and a processing system. In operation of the sensor, the laser beam is continuously reflected to the reflecting mirrors in the fixed reflecting mirror and the movable reflecting mirror which are parallel, and finally irradiates onto the two groups of photoelectric detectors, and the reflecting path of the laser beam can be changed when the distance between the fixed reflecting mirror and the movable reflecting mirror is changed; the laser beam is induced for multiple times by three detection parts on each group of photoelectric detector, the processing system obtains a detection distance value according to the laser-beam induction times and the laser induction sequence of each group of detection parts and the distance processing among the detection parts, and then can calculate out a real change value of the distance between the fixed reflecting mirror and the mobile reflecting mirror by the detection distance value; the novel alternative incremental sensor is simple in structure, reliable in measurement, higher in accuracy and easy in implementation of batch manufacture.

The invention relates to a high precision gyro motor bearing loading method. The loading can be achieved by using of a gyro motor loading device, and the gyro motor loading device consists of a machine frame, a platform surface, a horizontal guide rail system, a lifting guide rail system, two displacement sensors, an air bearing support, weights, an air shaft, a bearing centering sleeve and a bearing centering base. The centring can be achieved through a shaft at one end of the gyro motor, and the positioning can be achieved on an outer ring of a bearing, weights are placed in a weight plate, and required loads (namely, preloads) are added on an outer ring of a bearing at the other end through the air bearing. Then the size between two sets of bearing outer ring shaft shoulders is measured with a method of differential measurement through a displacement sensor 1 and a displacement sensor 2 which are calibrated. The height size of an outer rotor of the gyro motor is matched according to the measured size, and the post-installed preload of the gyro motor is guaranteed. The loading precision is greatly improved, errors caused by that the loading force does not pass through the center line of the motor bearing are eliminated, and the displacement measurement accuracy is improved.

In the position control system, multiple feedbacks such as displacement and speed are used to improve control accuracy. The grating has the advantages of precision, large range, and low cost as displacement feedback. This paper proposes the use of wavelet transform to realize the dual-parameter simultaneous extraction of the displacement and velocity of grating Moiré fringes. The scale factor corresponds to the velocity, the translation factor corresponds to the displacement, and the modulation changes The traditional grating Moiré fringe only measures single parameter of displacement and multi-parameter sensor realizes multi-parameter feedback, which is of great significance for improving positioning accuracy and simplifying the structure of the positioning system.

The present invention discloses an precise observation apparatus for rapid liquid bridge separation between parallel plates, wherein an upper base plate and a lower base plate are connected through a guide shaft, the lower base plate is fixedly arranged on an observation frame, a movement plate sleeves on the guide shaft to move up and down, the top surface of the lower base plate and the bottom surface of the movement plate are respectively provided with an upper plane flat crystal assembly and a lower plane flat crystal assembly, parallel and coaxial upper plane flat crystal and lower plane flat crystal are fixed on the upper base plate and the lower base plate, a liquid bridge is formed between the upper plane flat crystal and the lower plane flat crystal, a drive assembly is positioned on the top surface of the upper base plate, a tensile force measurement assembly is arranged between the drive assembly and a movement plate assembly, a displacement measurement assembly is arranged on the movement plate, and the side surface and the bottom of the observation frame are provided with high speed cameras. According to the invention, the process of precise observation on rapid liquid bridge separation between parallel plates is achieved, advantages of high parallel plate parallel degree, high separation speed verticality, high measurement precision and the like are provided, and precise observation on contour evolution and capillary force of the liquid bridge between the parallel plates under different separation speed conditions can be achieved, wherein the initial distance between the parallel plates is 100 mum.

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.

The invention discloses a bubbling experiment device for the mechanical-electric-magnetic coupling behavior of an electromagnetic intelligent material and a test method. In the invention, the tested film material is subjected to elastic deformation, plastic deformation, interface cracking and even self fracture by a bubbling method under the effect of full coupling of the mechanical-electric-magnetic fields, and the device realizes real-time testing on the mechanical, electric and magnetic response of the tested material in the process, thereby being favorable for obtaining the information of the functional film material in multiple aspects and for understanding the internal mechanism more clearly and thoroughly; in the existing oil-pressure bubbling loading device, a closed-loop control mode is adopted to control the oil pressure loading for the first time, and multiple oil pressure loading modes are realized so as to widen the representation functions of the bubbling test device; by adopting the projection speckle and digital image related technology, the non-contact three-dimensional deformation test is realized on the film sample, and the displacement measurement accuracy is improved to 20nm; and the device and method are favorable for researching the mechanical, electric and magnetic comprehensive performance of the novel functional film material.

The invention belongs to the technical field of precision displacement measurement, and provides a displacement measurement system based on an electromagnetically induced transparent atomic grating, including a coupled laser source, a detection laser source, an offset frequency-locked optical path, an electromagnetically induced frequency-locked optical path, a reference interference optical path, and a measuring Interference optical path and photoelectric detection optical path; the present invention builds the corresponding standing wave field structure through the interference optical path, periodically modifies the refractive index in the atomic medium under the mechanism of electromagnetic induction transparency, and constructs an atomic grating with adjustable grating pitch. The channel photodetector is used for detection, and the displacement measurement through the atomic grating is realized, which improves the measurement accuracy. Moreover, the present invention breaks through the limitation that the pitch of the grating cannot be adjusted, and can reasonably set the pitch according to the different displacement degrees of the object to be measured, so as to realize a grating displacement measurement system with adjustable minimum displacement resolution, thereby adapting to various environments. Displacement measurement needs.

The invention relates to a displacement measurement method based on resistance creep of a composite conductive polymer pressure sensitive material, belonging to the technical field of measurement. The method uses resistance creep to reflect displacement variation in real time instead of inhabiting resistance creep. In calibration, resistance-strain properties at the moment of finishing loading application and during creep stage are respectively obtained, and corresponding algorithms are respectively compiled; and in monitoring, at first, the stress phase of the pressure sensitive material is judged through the variation of resistance, and then a corresponding algorithm is used to obtain the real-time displacement value. According to different stress states, the measurement method of the invention uses different calibration methods and algorithms and considers time factors, thus further eliminating the adverse effects of resistance creep of the pressure sensitive material on displacement measurement. As the traditional method of adding nano powder to the substrate to reduce resistance creep is not used, the flexibility of the pressure sensitive material is ensured.