224results about How to "No drift" patented technology

The invention discloses a stepper motor out-of-step compensation method which is used to control an ultrasonic probe. The ultrasonic probe comprises a transducer and a stepper motor. The method comprises the following steps: acquiring the actual position information of the transducer; comparing the actual position information with target position information to get out-of-step data of the stepper motor; comparing the out-of-step data with a preset threshold to determine the threshold scope to which the out-of-step data belongs; and determining a compensation mode corresponding to the out-of-step data according to the threshold scope, and implementing a compensation operation corresponding to the compensation mode. According to the method, adaptive compensation is made by use of a compensation mode corresponding to the out-of-step condition of the stepper motor according to the out-of-step condition to prevent accumulative error of the relative position of the transducer, so that an image scanned by the ultrasonic probe is more accurate and does not drift. The invention further discloses a stepper motor out-of-step compensation device which has the same beneficial effect.

The invention refers to a kind of measuring device for measuring the brake moment of elevator arresting gear, especially measuring device and the method which uses torsion lever and strain piece as sensitive elements, and uses microprocessor to carry on signal calculation, analysis and process. The invention is made up of beam, torsion lever, main shaft, arresting gear and circuit. The arresting gear is connected with the beam through two pin shafts, the braking beam is connected to one end of the torsion lever, and the braking clamp is connected with the iron core, and then connected with the beam. The arresting gear coil is embedded in the iron core, there set strain pieces on the surface of torsion lever, the pieces are connects into a bridge circuit. The advantages of the invention are: it designs the zero calibration, deficiency analyzing of arresting gear and so on. It has a high accuracy, no float, and high reliability.

The method discloses a robust video object tracking method, and the method comprises the steps: sampling a candidate target particle based on the particle filter importance sampling principle; filtering out divergent particles based on the cosine similarity between the candidate target particle and a former tracking result; representing the screened candidate target particle based on a template dictionary linearly; building a low-rank sparse mathematic model of a linear coefficient matrix; solving a coefficient matrix based on an incorrect lagrangian multiplier optimization algorithm; selecting an optimal candidate object according to a discrimination function to serve as a tracking result; and updating the template dictionary in an on-line manner. The robustness of the method guarantees that the method can meet various types of challenges, and achieves the accurate tracking of a target in a video. The method solves a problem of inaccurate tracking and drift of the target in the video, wherein the problem is caused by illumination variation, scale change, shading, deformation, movement fuzzy, quick movement, rotation, background clutter, low resolution and others.

The invention discloses a film pasting device. An antiskid soft cushion and a baffle are arranged on a face plate of a base and used for locating a mobile phone, a film suction and location frame is located outside the baffle, a film suction device at the top end of the film suction and location frame is suspended above the antiskid soft cushion, a protection film sucked by the film suction device keeps opposite to a mobile phone screen in position, a sliding groove is formed in a base of a film pressing device, a rotating rod with one end inserted in the sliding groove in a penetrating mode and a rolling barrel crossing the upper portion of the corresponding base are suspended above the mobile phone in a parallel mode, the rotating rod is connected with an attaching film, the rolling barrel presses the upper portion of the protection film transversely, and the rotating rod and the rolling barrel achieve pasting of the protection film and separation of the attaching film synchronously in a rotating displacement process in the sliding groove. According to the film pasting device, the film can be pasted smoothly in order, operation speed is high, and the film pasting device is easy and convenient to use.

The invention relates to an electrode plate wrapping method, which comprises the steps of: first, arranging a positive electrode plate and a negative electrode plate in an electrode plate material box vertically respectively, above all using a sucking disc to suck the positive electrode plate laterally, then turning the positive electrode plate downward by 90 degrees and placing it in a material trough, moving the positive electrode plate placed in the material trough forward by one working position, at the same time moving separator paper from top to bottom, cutting the separator paper off and disposing it on the material trough vertically, further moving the positive electrode plate forward by one working position, and making the front end of the positive electrode plate contact the central part of the separator paper in the moving process, along with the forward moving of the positive electrode plate, wrapping the positive electrode plate with the separator paper, then further moving the positive electrode plate forward by one working position, simultaneously employing the sucking disc to suck a negative electrode plate laterally, and placing the negative electrode plate right over the wrapping completed positive electrode plate, then keeping moving the negative electrode plate, the separator paper, and the positive electrode plate forward into a material receiving device, and when the number of a plate pack is collected, sending the plate pack out.

The present invention relates to a wide-angle broad-spectrum reflection film and its production method. The reflecting film includes glass base. On the glass base first transition layer, metal film layer and reinforced film layer are successively deposited, perfectly, between first transion layer and metal film layer a second transion layer can be added. Said invention adopts double transion layer structure, and its spectral reflectance is high.

The invention relates to dinotefuran granules and a preparation method thereof. The dinotefuran granules have effective components of dinotefuran and the balance of pesticide adjuvant and carriers, wherein the mass percent of the dinotefuran in the dinotefuran granules is 0.01-10%. The invention also discloses the preparation method of the dinotefuran granules. The dinotefuran granules provided by the invention are suitable for controlling pests of crops such as rice, wheat, vegetables, fruit trees, etc.

This invention discloses a phase-locking laser frequency stabilizing method realized by a phase-locking laser frequency stabilizing device composed of a tunable laser, a beam splitter, a frequency stabilized primary standard source, a photoelectric detector, a modulated signal source, a phase-sensitive wave detector and a tunable drive, characterizing in applying the modulated signal output by its source onto the frequency stabilized primary standard source to lock the laser frequency on a target frequency point the output laser has no frequency shift.

The invention provides a high-temperature well temperature and pressure dynamic monitoring system. According to the high-temperature well temperature and pressure dynamic monitoring system, corresponding data are figured out through processing of software of a central automatic control system (7) and are respectively transmitted to a mechanical electronic direct reading double display screen (9) and a data storage and teletransmission system (8), pressure, temperature, working fluid level height and steam dryness data of various teletransmission layers are respectively displayed and stored, and a technological structure and method for temperature and pressure dynamic monitoring or moving testing of a high-temperature well is completed. According to the high-temperature well temperature and pressure dynamic monitoring system, installation and operation are convenient and fast, interference of other transmission environments does not affect the monitoring system, a drifting phenomenon do not exist, correction is not needed, the monitoring system can stably operate under a high-temperature environment of an oil well for a long time, all the data can be directly read, stored and transmitted in a remote mode, and testing results are intuitive and precise.

The invention discloses a combustion control system for a power plant. The combustion control system comprises a data acquisition part, a control part and an execution part. The data acquisition partcomprises a sound wave temperature measurement system and a DCS data acquisition system. The control part comprises a neural network model module, an evaluator and an optimizer. The execution part comprises a secondary air door opening degree adjusting device. The invention further discloses a combustion control method for the power plant. According to the system and the method, a neural network is adopted to construct a model, and extremely high universality and transportability are achieved. According to the system and the method, stable, long-term and manual intervention-free combustion canbe achieved for the power plant, and the purposes of reducing coal consumption and NOx and CO emissions as much as possible, reducing the combustion temperature of a hearth, uniform combusting and reducing the smoke temperature under the condition of a given load can be achieved.

The invention provides a three-stand-column semi-submersible type offshore wind turbine foundation which serves offshore wind energy development. The three-stand-column semi-submersible type offshorewind turbine foundation comprises three vertical stand columns arranged in a triangular shape, the overwater height of the stand columns is about 1 / 3-1 / 4 of the total height of the foundation, a winddriven generator is mounted at the top of the main stand column, the underwater bottom end of the main stand column is connected with the two peripheral secondary stand columns through floating barrels, and the included angle between the two floating barrels ranges from 60 degrees to 90 degrees. The structural style is simple, and the force transferring route is clear. The stand columns are hollow, and stiffening ribs and ballast cabins are arranged. Anchor gears are arranged on decks of the three stand columns, fair leads are fixed to column bodies, and tension ribs are connected with external ballast on the seabed. The contact degree of the externally hung ballast and the seabed, the inclination angle of a fan-foundation system is controlled, and efficient wind energy collection is guaranteed. A braced chain is adopted by the foundation for mooring, and connected with a pull type anchor on the seabed.

An oil pressure warning sensor for a pressure sensitive capacitor relates to a sensor, which comprises a telescoping oil tank main element, an oil tank telescoping component arranged in the telescoping oil tank main element, and a casing cooperating with the telescoping oil tank main element to close the oil tank telescoping component in the telescoping oil tank main element, wherein the telescoping oil tank main element comprises an iron-bottomed bowl and screws in sealed fit with through holes reserved at the bottom of the iron-bottomed bowl; the oil tank telescoping component comprises a sealing washer, a waveform return spring plate, a knurled spring plate, a sliding sleeve, a movable electrode plate, a return spring, a double-sided circuit board and a circuit board retaining snap ring, which are arranged in the iron-bottomed bowl in turn; a fixed electrode plate is arranged on one side, close to the movable electrode plate, of the double-sided circuit board; the movable electrodeplate and the fixed electrode plate form a capacitor with variable capacitance; upon receiving the pressure from the engine oil, the waveform return spring leaf and the knurled spring leaf deform anddrive the movable electrode plate to compress and deform the return spring so as to change the distance between the movable electrode plate and the fixed electrode plate to change the capacitance of the capacitor; and the oil pressure warning sensor for the pressure sensitive capacitor is further provided with a control circuit connected with the capacitor and used for converting the variation ofoil pressure into an electrical signal and transmitting the electric signal to an oil instrument.

The invention relates to a multifunctional absorbing vessel used for absorbing an underwater highly radioactive foreign matter and a fishing technology. According to the fishing technology, an underwater dust collector is used cooperatively with a fishing tool to perform fishing of the highly radioactive foreign matter under a water shielding working condition, and the highly radioactive foreign matter can be preserved in the fishing tool so that analysis and evidence obtaining work can be conveniently carried out after the fishing process. According to the multifunctional absorbing vessel used for absorbing the underwater highly radioactive foreign matter and the fishing technology, a large-scale radioactive foreign matter shielding flask does not need to be prepared, the fished highly radioactive foreign matter can be conveyed to a spentfuel storage pool for temporary storage, and the highly radioactive foreign matter can be taken out from the spentfuel storage pool at any time when needed, so that the highly radioactive foreign matter is subjected to evidence obtaining and analysis. According to the fishing technology, long time limit for a project and a large amount of cost in processing equipment for highly radioactive waste in a later period are saved, and convenient conditions for technological analysis in the later period are provided.

The invention provides an arbitrary bias point control system for an M-Z modulator, comprising: an M-Z modulator; an optical coupler; a photoelectric conversion amplifier used for receiving an opticalsignal provided by the optical coupler, and converting the optical signal into an electrical signal for amplification; a first low pass filter used for filtering out a fundamental component of the electrical signal; a band-pass filter used for filtering out a second harmonic component of the electrical signal; a second low pass filter used for filtering out a low-frequency direct current component of the fundamental component; a third low-pass filter used for filtering out a low-frequency direct current component of the second harmonic component; a divider used for performing division operation on the low-frequency direct current components in the fundamental component and the second harmonic component to obtain an offset error correction voltage; and an adder used for adding an offset error correction voltage, a low frequency jitter signal, and a direct current bias voltage to obtain a corrected direct current bias voltage, and supplying the corrected direct current bias voltage to the direct current bias terminal of the M-Z modulator. The invention is capable of achieving accurate control of any bias point of the M-Z modulator in a wide temperature range.

The present invention provides a method of generating the test vectors. The method includes: A. the phase of the synchronous clock of the synchronous circuit and the overturning time point of the asynchronous signal are obtained, and a phase interval of the synchronous clock provided for the synchronous circuit is determined; B. the configuration information of the phase locked loop PLL is adjusted to make sure that the synchronous clock phase output according to the configuration information by PLL is in the phase interval calculated in the step A; C. the test vectors are generated by using the adjusted PLL configuration information. In the present invention, test vectors can be generated through adjusting the configuration information of PLL, and in the testing process, said test vectors assure that the synchronous signals output by the synchronous circuit not generate excursion. Thus, the chips having perfect functions can all pass the test and the testing of the robustness of the vectors are improved.

The invention discloses an enclosed petroleum coke dehydration degassing transportation system and method. The system includes: a coke slide tank, a vibration screening machine, a crusher, a water filter tank, a pipe type conveyor, a water distribution bin, a vibrating feeder, a coke cut water lift pump, a coke cut water filter and a tail gas treatment unit. The coke slide tank is a tubular structure, one end is connected to the bottom outlet of a coke tower, and the other end is connected to the vibration screening machine and the crusher in order. The crusher outlet is connected to the top of the water filter tank, the water filter tank bottom is provided with the pipe type conveyor, and the other end of the pipe type conveyor is connected to the upper part of the water distribution bin. The middle part of the water filter tank is connected to the coke cut water lift pump and the coke cut water filter in order, and the coke cut water filter bottom is connected to the upper part of the water filter tank. The coke slide tank, the vibration screening machine, the water filter tank and the water distribution bin are respectively equipped with a pipeline in connection with the tail gas treatment unit. The whole system is an enclosed structure, realizes a decoking process free of dust, harmful gas and waste residue, reduces environmental pollution, improves the automation level, and lowers the labor intensity.

The invention relates to an optical fiber double Fabry-Perot cavity ultrasonic sensor for partial discharge detection and a manufacturing method thereof. The optical fiber double Fabry-Perot cavity ultrasonic sensor comprises a light source, an optical fiber 1 / 2 optical splitter, an optical fiber, an optical fiber coupler, an optical fiber EFPI double Fabry-Perot cavity probe, a double-channel photoelectric detector, a high-speed data acquisition device and a differential denoising algorithm module. The light source is connected with the optical fiber coupler through the optical fiber 1 / 2 optical splitter, the optical fiber coupler is respectively connected with the optical fiber EFPI double Fabry-Perot cavity probe and the double-channel photoelectric detector, the double-channel photoelectric detector is connected with the high-speed data acquisition device, and the high-speed data acquisition device is connected with the differential denoising algorithm module. Compared with the prior art, the advantages of eliminating interference deviation of the system and the external environment to the Fabry-Perot cavity during working and the like can be achieved.

The invention discloses an absorbing plumping bag and its production method. The points of the technological scheme are: the absorbing plumping bag is composed of the outer bag (gunny-bag or plastic compound bag), the inner bag (chemical fabric bag or non-woven fabrics bag) and the absorbing plumping agent. There are 4 to 16 connective bands on the upper and the lower plane of the outer bag. The absorbing plumping bag of the invention is widely applied to the flood fighting, water conservancy and building operation. In the construction, we can connect the outer bags with each other tightly to improve the overall strength and stream impact resistant property of the absorbing plumping bag. When the absorbing plumping agent in the bag meets with the water, its weight and volume will increase by more than 10 times quickly. Being struck by water, it will not flow and is benefit to the safe and rapid construction. When the flood fighting or construction is finished, the absorbing plumping bag can be reused after insolation.

A single-light source low concentration ozone concentration detector comprises two gas dividers, a zero gas processing device, a gas circuit switching device, a detection cell, a signal amplifier, an AD converter, a flow sensor, a temperature sensor, a pressure sensor, a control processing module, a display device and a gas pump; the detection cell comprises an ultraviolet lamp tube, a lamp chamber, a gas chamber and an ultraviolet light intensity probe, the ultraviolet lamp chamber is provided with a light hole, two end portions of the gas chamber respectively align at and are perpendicular to the light hole and the ultraviolet light intensity probe, the gas chamber is provided with a gas inlet and a gas outlet, the input end of the first gas divider is connected with the gas source, the output end of the first gas divider is respectively connected with the input ends of the zero gas processing device and the second gas divider, and the output end of the zero gas processing device is connected with the input end of the gas circuit switching device; and the output end of the second gas divider is connected with the pressure sensor and the gas circuit switching device, the output end of the gas circuit switching device is connected with the gas inlet of the gas chamber, the input port of the flow sensor is connected with the gas outlet of the gas chamber, and the output port of the flow sensor is connected with the gas pump.

The invention provides a bar material drill and adopts the technical scheme that the bar material drill comprises a drilling mechanism, a propelling mechanism for pushing the drilling mechanism to advance, a support mechanism for supporting a bar material, and a positioning device for positioning the bar material, wherein the drilling mechanism comprises a motor I, a reduction gearbox and a drill bit, the reduction gearbox is in transmission connection with the motor I, the drill bit is fixedly connected with the output end of the reduction gearbox, the positioning device is positioned at one end of the drill bit, and the drilling mechanism can be pushed by the propelling mechanism to move towards the positioning device. The bar material drill has the benefits that the motor I is fixedly mounted on the reduction gearbox, so that the drilling mechanism can move forwards and backwards without affecting the transmission of the motor; besides, a screw is driven by the motor to push the drilling mechanism to advance, the feeding of the drill bit is realized, the drilling depth is effectively controlled, deviating phenomena cannot occur in the feeding process, drill bit breaking problems are effectively avoided, the structure is simple, and the operation is convenient.

The invention discloses a contact type four-electrode salinity sensor based on an MEMS (micro electro mechanical systems) technology. The salinity sensor comprises a quartz substrate, a Si3N4 adhesion layer and platinum metal electrodes, wherein the Si3N4 adhesion layer is located on the upper surface of the quartz substrate, and the platinum metal electrodes are located on the Si3N4 adhesion layer; the platinum metal electrodes comprise contact zones, conductivity sensing electrodes and temperature sensing electrodes; Si3N4 protection layers are arranged on the front surface and the back surface of the contact type four-electrode salinity sensor based on the MEMS technology respectively; and a window is etched in the front surface of the Si3N4 protection layer, and the conductivity sensing electrodes and the temperature sensing electrodes are exposed. The invention further discloses a measurement method of the contact type four-electrode salinity sensor based on the MEMS technology, the conductivity is calculated according to the alternating current, the voltage difference and the like, and the salinity is calculated further. The contact type four-electrode salinity sensor based on the MEMS technology is small in size, has a larger measurement range and higher stability, can be contacted with seawater directly for a long time, and doesn't drift.

The invention relates to a liquid formulation for trunk injection, in particular to the liquid formulation for trunk injection, which is used for preventing and curing kiwifruit canker. The liquid formulation for trunk injection adopts an active component, actually, a low-toxic agent which is no harmful to non-target organisms, environment, people and livestock. Therefore, the liquid formulation for trunk injection is suitable for kiwifruits and can effectively prevent the incidence and prevalence of the kiwifruit canker, and can cure the kiwifruit canker; meanwhile, the bactericide performance is better, as a mixed agent is adopted, rather than a single agent; and moreover, the use cost is effectively reduced, and drug resistance of bacteria is also reduced.

The invention discloses a method for improving handling efficiency of containers (or bulk cargo) and equipment thereof. The equipment is a floating pier with self-propulsion and continuous propulsion functions, wherein, the floating pier is arranged on a submarine locating platform, handling mechanical equipment carries out handling operation at one side by the sea, and the unloaded (loaded) containers (or the bulk cargo) are output or input by floating pier horizontal transportation equipment. The invention has the following advantages: 1. compared with the traditional handling mode, the handling efficiency is doubled; 2. dead-weight of the structure of the mechanical equipment is lowered on the existing basis, thus saving a great amount of investment cost; 3. infrastructure investment cost of ports and docks is greatly reduced; and 4. the floating pier is firmly bonded with the submarine locating platform without displacement, thus greatly improving safety performance, guaranteeing safety of the floating pier during the handling process, achieving the purpose of handling the containers (or the bulk cargo) from two sides of a ship at the same time, enhancing the handling efficiency, accelerating the ship turnover, and saving a great quantity of shore land of the ports and the docks and a great quantity of infrastructure cost of the docks.

The invention discloses a polyvinyl alcohol nanofiber emboliaztion agent as well as a preparation method and application thereof and belongs to the field of vascular thrombosis materials for interventional therapy. The polyvinyl alcohol nanofiber emboliaztion agent consists of polyvinyl alcohol electrostatic spinning nanofiber granules, wherein the particle sizes of the nanofiber granules is 100-300mu m. The preparation method comprises the following steps: dissolving polyvinyl alcohol granules into water, and heating till the polyvinyl alcohol granules are completely dissolved so as to obtaina polyvinyl alcohol solution of an appropriate concentration as an electrostatic spinning solution; preparing a polyvinyl alcohol nanofiber film from the electrostatic spinning solution by using electrostatic spinning equipment; performing thermal treatment on the nanofiber film; shearing the nanofiber film after thermal treatment, performing low-temperature crushing treatment, and screening, thereby obtaining the polyvinyl alcohol nanofiber granules of which the particle size is 100-300mu m. The emboliaztion agent disclosed by the invention has relatively good treatment effects and biological security, and can be also applied to arterial embolism of various types of malignant tumor such as primary liver cancer and kidney cancer.

The invention provides a method for measuring posture and height of a dynamic platform. According to the technical scheme, the method comprises the following steps of: obtaining pavement scanning lines by utilizing two two-dimensional laser scanners which are orthogonally mounted and perform vertically downward scanning; estimating an expression equation of the scanning lines by using an RANSAC (random sample consensus algorithm), and obtaining a pavement plane equation by utilizing the expression equation of the two scanning lines; and solving the posture and height of the platform by taking the pavement plane equation as reference. The equipment is simple and is low in cost. The measurement result is not influenced by the acceleration of the motion platform, drift is avoided, and the measurement accuracy is high.

A three-position four-way electromagnetic ball type reversing valve comprises electromagnets and valve bodies. A hydraulic pilot stage and a hydraulic power amplifier stage are arranged in each valve body; each hydraulic pilot stage comprises a valve base, an ejector rod is arranged in each valve base, the two ends of each ejector rod are provided with two steel balls and a cock respectively, and each hydraulic pilot stage is arranged at the output end of the corresponding electromagnet. Each hydraulic power amplifier stage is divided into two paths which each comprise a valve base, steel balls, a valve sleeve, a spring and a piston, and different power flows can be obtained by selecting the steel balls of different diameters and the valve bodies of different diameters. Non-leakage and non-drifting control over zero closing of the reversing valve is achieved, the disjointed radial and axial clearance between the steel balls and the valve bases is 1.2 mm, non-clogging and non-clamping flow control is achieved, and the problems of clogging, clamping and drifting frequently happening to double nozzle baffle type electro-hydraulic servo valves, jet pipe type electro-hydraulic servo valves, proportional valves and electromagnetic directional valves are solved.

The invention provides an estimation method of the wind velocity of the echoes of the wind field of the low-altitude wind shear of an airborne radar. According to the estimation method of the invention, white noises are subjected to modeling by a p-order all-pole filter, so that wind shear radar echo signals are generated; the autocorrelation coefficient of the low-altitude wind shear radar echo signals is calculated; the coefficient of an autoregressive model is calculated, so that a wind shear radar echo power spectrum is obtained; the pole of an equation is calculated; a velocity corresponding to the pole is obtained; and the velocity of the pole is judged, so that power and an average wind velocity can be outputted. The calculation amount of the method of the invention is small. With the estimation method adopted, the limitations of previous schemes are eliminated; clutter filtering is not needed; the accuracy of wind field echoes can be ensured; a condition that the pole drifts tothe direction of ground clutters can be avoided, and therefore, results are more accurate; simulation results can easily verify that the wind velocity estimation method provided by the present invention can reflect actual wind velocities, is effective and reliable, and is suitable for wind shear signal processing under turbulent flow conditions and strong ground clutter conditions.

The invention discloses a weighting local multi-task sparse tracking method with robustness, so as to improve the accuracy rate of tracking a target object. The method is as follows: target templates are initialized, and block processing is performed on each target template, thereby obtaining a template dictionary; candidate target particles of a current frame are obtained based on a Gaussian random sampling principle, and block processing is also performed on the candidate target particles; the candidate target particles after block processing is linearly expressed based on the template dictionary; stray particles are captured based on a local multi-task sparse tracking model; a globally optimal solution of the tracking model is obtained based on a near-end gradient acceleration method; a tracking result is determine according to observation likelihood; and the template dictionary is updated on line. The weighting local multi-task sparse tracking method with robustness can effectively prevent a phenomenon that tracking is inaccurate or even drifts from being caused by illumination variation, scale variation, sheltering, deformation, rapid movement, rotation and background clutter of a target object in a video, thereby achieving the purpose of accurately and continuously tracking the target object in the video.

The invention relates to an air cleaner and an engine control system. The air cleaner (10) is provided with a housing (11) for housing therein an inner tube filter (13) and an outer tube filter (12) and comprising a case body (11A) having an open end face closed by a lid member (14). The housing (11) is provided with an air intake opening (15) provided in the outer peripheral surface of the case body (11A) and taking in outside air, and also with an air discharge opening (16) provided in a bottom surface (111) of the case body (11A), which bottom surface is located on the air flow downstream side of the case body, and discharging the air taken in from the air intake opening (15) and filtered by both the inner tube filter (13) and the outer tube filter (12). Inside the air discharge opening (16) is provided a mass flow rate sensor (19) for measuring the flow rate of the air. On the upstream of the mass flow rate sensor (19) is provided a flow regulating grid (18) for regulating the flow of the air.

The invention discloses an equal altitude test apparatus of air floatation blocks. The apparatus is used for the equal altitude test before installing air floatation blocks required by the motion of an H-shaped large-stroke high-precision stage in a lithography machine. The equal altitude test apparatus of air floatation blocks comprises a horizontally arranged platform and foundations having adjustable heights and arranged under the platform, and a parallel gauge, a square foot, anti-thrust mechanisms, a standard thrust column, a crimping mechanism and a thrust mechanism are arranged on the platform. The relative altitude values of all the ball-joint air floatation blocks can be measured through the apparatus, so the air floatation surface of a plurality of groups of ball-joint air floatation blocks at two ends of a motion module reaches a 0.004mm co-planarity degree requirement.