41 results about "Linear variable differential transformer" patented technology

The invention provides a transformer type differential signal acquisition system and method, and relates to the technical field of signal acquisition, and the system comprises a switching power supply module which is used for supplying power to the system; the input module is used for collecting wire feedback signals; the operational circuit is used for rectifying the feedback signal, performing differential processing and filtering on the rectified feedback signal to obtain a differential filtering signal, adding bias voltage to the differential filtering signal, and amplifying the differential filtering signal to obtain an amplified signal; the analog-to-digital conversion module is used for converting the amplified signal into a digital signal; the CPU processing module is used for processing the digital signal, generating a control signal and sending the control signal to the output module and the communication module; the output module is used for generating current according to the control signal; and the communication module is used for sending the control signal to an upper computer through the communication interface, so that the upper computer calibrates the linear variable differential transformer. The linear variable differential transformer has the technical effect that the measurement precision of the linear variable differential transformer is improved.

The triaxial apparatus system comprises a triaxial pressure chamber, a top cover and a base are arranged at the upper end and the lower end of a sample arranged in the triaxial pressure chamber respectively, and each of the top cover and the base comprises an anti-freezing solution inlet and an anti-freezing solution outlet; a spiral copper pipe is arranged in the triaxial pressure chamber and is connected with the hot bath system through a sealing connecting pipeline; the GDS pneumatic controller is connected into the triaxial pressure chamber, the load sensor applies axial force to a sample, the GDS backpressure controller is connected to the bottom of the triaxial pressure chamber, and the linear variable differential transformer LVDT is arranged outside the triaxial pressure chamber; and the axial Hall effect sensor and the radial Hall effect sensor are respectively arranged at the axial position and the radial position of the sample. The device is simple in structure, convenient to operate, high in measurement precision and good in repeatability and reliability, and the precision and efficiency of frozen soil mechanical property research are remarkably improved.

The present disclosure describes a system and method of charging a vehicle in a parking lot. The system is communicatively coupled to one or more robots, one or more user devices, and one or more portable charging apparatus, via a network. The one or more robots travel autonomously and connect to one or more portable charging apparatus upon receiving a vehicle charging request. The one or more robots further navigate the one or more portable charging apparatus to vehicle's parking location. Each robot is capable of engaging with the portable charging apparatus via a towing mechanism present in rear portion of the robot. The towing mechanism actuates upon receiving the data from the plurality of sensors and upon reaching the robot within a predefined range of the portable charging apparatus, enabling precise alignment and connection between the robot and the portable charging apparatus via linear variable differential transformer (LVDT).

The utility model provides a thermal power generating unit steam turbine control valve double-LVDT (linear variable differential transformer) feedback device, which comprises a fixedly arranged mounting frame and two LVDT displacement sensors, and the LVDT displacement sensors are provided with sensing rods (1.1); the front fixing sleeve plate is provided with two magnetic rings, the induction rod of each LVDT displacement sensor is inserted into the corresponding magnetic ring, and when the piston rod moves, the induction rods and the magnetic rings can move relatively. The system further comprises a DEH control system which can control and collect signals of the double LVDT feedback devices. According to the steam turbine control valve, the double LVDT feedback devices are adopted for displacement of the control valve, the two LVDT feedback detection devices are independently arranged, when any VP card, an LVDT displacement sensor and an external connecting wire are short-circuited or open-circuited, a redundant backup feedback line can be directly switched without interference, operation of a unit cannot be affected, and detection feedback reliability and equipment operation safety are improved.

The invention discloses a variable-speed regulation electric centrifugal pump with flow feedback and a flow control method thereof, and belongs to the technical field of aero-engine control. The electric centrifugal pump comprises a permanent magnet synchronous motor, a centrifugal pump body, an equal pressure difference adjusting valve, a metering valve, a linear variable differential transformer and a motor controller. And the motor controller receives a fuel mass flow instruction of the engine controller and a metering valve opening signal fed back by the LVDT, outputs a motor control instruction and adjusts the rotating speed of the centrifugal pump to change the outlet pressure of the centrifugal pump. The constant-pressure-difference regulating valve senses the pressure change, drives the valve core of the metering valve to move, and changes the opening degree of the metering hole, so that the fuel flow is regulated; the LVDT detects the opening degree in real time and feeds back the opening degree, and flow closed-loop control is formed. According to the invention, on-demand supply of pump outlet pressure is realized through variable-speed regulation, accurate metering and feedback of flow are realized through the synergistic effect of the equal-pressure-difference regulating valve and the metering valve, pressure loss caused by a traditional throttle valve is eliminated, and the system efficiency is remarkably improved.

A measurement correction method and signal conditioning apparatus for a linear variable differential transformer sensor. The correction method comprises the following steps: acquiring a compensation fitting coefficient (101); obtaining a root mean square value signal of an excitation voltage signal, a phase difference signal and a root mean square value signal of an induced voltage signal of when a linear variable differential transformer sensor is used to measure the displacement of an object to be measured (102); and on the basis of the numerical value of the root mean square value signal of the excitation voltage signal, the numerical value of the phase difference signal and the numerical value of the root mean square value signal of the induced voltage signal of said object and in view of the compensation fitting coefficient, performing temperature drift compensation, so as to obtain a corrected displacement measurement value (103). The above solution can compensate for the displacement data drift caused by the impact of temperature on a linear variable differential transformer sensor, thereby reducing the impact of temperature drift on the output of the linear variable differential transformer sensor.

The utility model discloses an LVDT (Linear Variable Differential Transformer) sensor support dismantling tool, which belongs to the technical field of LVDT sensors and comprises a support frame, a through hole is formed in the surface of the support frame, assembly grooves are symmetrically formed in the surface of the support frame, and reset springs are fixedly connected in the assembly grooves of the support frame. A supporting assembly is installed at the top end of the reset spring. Firstly, the LVDT sensor is removed from the interior of the lantern ring support, then the supporting frame is placed on an assembling face, the through hole of the supporting frame is erected outside the lantern ring support, the top plate is longitudinally pressed downwards relative to the supporting frame, the reset spring elastically deforms within the elastic limit, meanwhile, the clamping plates on the two sides slide towards the inner side along the carrying plate, and then the LVDT sensor is assembled. The rubber pads on the inner surfaces of the clamping plates are pressed on the outer wall of the lantern ring support, the good clamping effect is achieved, meanwhile, under the elastic force effect of the reset springs, the top plate is longitudinally lifted along the supporting frame, the lantern ring support is pulled out of the assembling face, and more labor is saved in the disassembling process.

The present invention discloses a linear variable differential transformer (LVDT) bracket for reducing the effects of lateral forces on the linear variable differential transformer (LVDT). The present invention comprises an LVDT sleeve, an LVDT feedback rod, a slide, a sliding head, a limit plate, and a limit cover. A protrusion for limiting is provided on the inner wall of the slide away from the LVDT sleeve. A limit groove matching the protrusion is provided on the outer wall of the sliding head near the LVDT sleeve to enable the sliding head to slide within the slide. Several springs are provided on the outer wall of the sliding head at one end away from the LVDT sleeve. The limit cover is sleeved on the outside of the sliding head. A limit portion is provided on the end surface of the sliding head at the end away from the LVDT sleeve. The limit portion comprises a connecting rod, a lower top plate, and an upper top plate. The lower top plate and the upper top plate are respectively fixed to the connecting rod. The limit plate defines a hole having a diameter smaller than that of the lower top plate and the upper top plate, and larger than that of the connecting rod. The limit plate is mounted between the lower top plate and the upper top plate and fixed within the limit cover.

The utility model belongs to the technical field of aviation electromechanics, and relates to a servo actuation control device. The device comprises a DSP (Digital Signal Processor) processing module, an LVDT (Linear Variable Differential Transformer) sensor acquisition module, a watchdog module, an electromagnetic valve driving module and a servo valve driving module, wherein the LVDT sensor acquisition module, the watchdog module, the electromagnetic valve driving module and the servo valve driving module are all connected with the DSP processing module. Under the cooperation of the electromagnetic valve and the servo valve, the hydraulic flow and direction acting on the steering engine are controlled, so that the steering engine is driven to move, and the position of the steering engine and a monitoring result are periodically reported to a flight control computer. And meanwhile, event data in operation can be recorded in the NVM, so that subsequent ground maintenance and management are facilitated.

The invention provides a sample deformation measuring system for an in-situ CT imaging ultra-high-temperature mechanical loading experiment, which adopts a high-temperature ceramic material as an auxiliary extraction design, extracts the deformation of a gauge length section of a sample out of a high-temperature furnace and measures the deformation by using an LVDT (Linear Variable Differential Transformer); meanwhile, in order to eliminate the influence of the deformation of the X-ray transmission thin wall in the high-temperature furnace on the deformation measurement of the sample, a video extensometer is also adopted to monitor the deformation of the thin wall in real time, and the LVDT measurement result is corrected according to the data, so that the high-precision deformation measurement in the ultra-high-temperature environment is realized; the measurement system can be compatible with a high-resolution in-situ CT imaging experiment, meets the requirements of mechanical loading and microstructure imaging at the same time in a high-temperature environment, improves the real-time performance and precision of the in-situ experiment, provides a powerful tool for comprehensively researching the mechanical property and behavior of a material, and has a wide application prospect. Therefore, the comprehensive in-depth research requirements on material performance and behaviors are met, and the blank in the prior art is filled up.

The invention relates to a simulation method and device for a linear variable differential transformer. The method comprises the steps that ideal parameters and interference parameters of input signals of a primary coil and inherent parameters and environmental parameters of the linear variable differential transformer are obtained; performing signal simulation according to the ideal parameter and the interference parameter to obtain an actual input signal of the primary coil; calculating the inherent parameters, the environmental parameters and the actual input signal of the primary coil through a secondary coil output signal calculation model to obtain a secondary coil output signal; and carrying out demodulation calculation on the output signal of the secondary coil to obtain displacement data. By introducing the magnetic conductivity difference and environmental interference of the secondary coil, the analog signal truly reflects non-ideal characteristics, errors and jitter in actual operation are reproduced, and the simulation precision is improved.

The utility model discloses a kind of temperature drift test fixtures for linear differential transformer type displacement sensor, shell pedestal and vertical fixed plate are respectively fixedly installed on the top of bottom plate, pull rod pedestal is placed on the top of bottom plate and between shell pedestal and vertical fixed plate, shell connecting device is located on the upper portion of shell pedestal, pull rod connecting device is located on the upper portion of the pull rod pedestal, the both ends of transverse guide rod are connected with shell pedestal and vertical fixed plate respectively, and middle section passes through the corresponding through-hole on the pull rod pedestal, the screw rod of first transverse adjusting bolt mounted on vertical fixed plate and the screw rod of second transverse adjusting bolt mounted on shell pedestal are respectively contacted with the both sides of pull rod pedestal.The utility model is convenient for accurately adjusting the relative position between pull rod and shell, to realize the function of shell positioning and pull rod movement control, and the concentricity between pull rod and shell can be guaranteed, so it can be used to test the temperature drift of specified position point.

A thick film integrated LVDT signal regulator comprises a metal fully-sealed tube shell and a ceramic substrate, the ceramic substrate is a thick film ceramic substrate and is sintered on the tube shell, the ceramic substrate is provided with a gold conduction band, and an excitation generation circuit, a demodulation circuit and a voltage reference circuit are arranged in the tube shell. The excitation generation circuit comprises a rail-to-rail operational amplifier U2A, a power operational amplifier U5, resistors R1-R13 and capacitors C1-C6; the demodulation circuit comprises operational amplifiers U3A, U7A and U7B, high-precision operational amplifiers U4A and U4B, a field efficiency tube T1, diodes D1 and D2, resistors R14-R31 and capacitors C10-C11. The beneficial effects are that the circuit is high in linearity, small in output ripple, low in temperature drift, high in frequency response precision, low in manufacturing cost, simple in design and manufacturing technology, and capable of realizing localization and satisfying use requirements.

To reduce the cost of making LVDT measurements we disclose a way to make an interface device that allows to perform LVDT measurements with a smart phone, a tablet, or other computing device capable of measuring analog electric signals. The device can also be used to make measurements with other sensors such as flux gate sensors.

The utility model provides an LVDT displacement sensor for an adjusting type valve actuator, and relates to the field of sensors.The LVDT displacement sensor for the adjusting type valve actuator comprises a coil framework, the coil framework is hollow, a connecting rod is installed in the middle of the coil framework, and the two ends of the connecting rod extend out of the coil framework; a first coil and a second coil are arranged on the side portion of the coil framework, a spring tray is arranged at the upper end of the connecting rod, a spring is arranged in the spring tray, and the bottom of the connecting rod is connected with an adjusting type valve actuator. The device is simple, stable and reliable in structure and high in measurement precision, and the control precision of the adjusting type valve can be greatly improved.

The invention discloses a bridge and tunnel health state monitoring method, which relates to the technical field of bridge and tunnel monitoring, and comprises the following steps of: planning and designing a monitoring system, installing and debugging a sensor, setting a data acquisition system, performing data transmission encryption transmission and preprocessing, performing data analysis and feature extraction, performing state evaluation and early warning and the like. Potential risks of a bridge or a tunnel can be found and early warned in time by determining acquisition frequency and time intervals, establishing a data storage format and a database, and performing encryption transmission and preprocessing on data transmission, and meanwhile, related personnel can receive alarm information in time by setting an early warning threshold value and an alarm mechanism, so that the safety of the bridge or the tunnel is ensured. A sensor and a strain gauge are selected according to selected monitoring parameters to measure strain, such as a resistance strain gauge, strain data are acquired by utilizing the characteristic that the resistance value of the resistance strain gauge changes along with strain, and a displacement sensor comprises a linear variable differential transformer and the like and can accurately measure the displacement change of the structure.

The present disclosure relates to a high-gear door valve rod rotation-stopping device, a high-gear door structure and a steam turbine, wherein the high-gear door valve rod rotation-stopping device comprises a high-gear door shell, a shaft sleeve, a linear variable differential transformer and a rotation-preventing rod, the high-gear door shell is provided with a first hole and a second hole, the shaft sleeve is located in the high-gear door shell and connected with a valve rod installed in the high-gear door shell, the shaft sleeve is used for synchronous action with the valve rod, one end of the linear variable differential transformer is connected with the shaft sleeve and the other end is located in the first hole, one end of the rotation-preventing rod is connected with the shaft sleeve and the other end is located in the second hole. The present disclosure sets the rotation-preventing rod, so that the rotation-preventing rod completely bears the force of the linear variable differential transformer during the movement of the high-gear door, effectively protects the linear variable differential transformer and realizes bidirectional redundant protection.

The invention belongs to the field of design and manufacture of high-pressure hydrogen storage containers, and discloses a load sensor resistant to influence of a high-pressure hydrogen environment, which adopts a linear variable differential transformer (LVDT) to replace a strain gauge to serve as a sensitive element for measuring deformation, adopts a material resistant to hydrogen embrittlement to manufacture a sensor elastic body, and connects the LVDT with the elastic body through a thread and tenon structure. During use, the elastic body is connected with a tested sample, an excitation signal is applied to the LVDT, and the magnitude of the load borne by the elastic body can be reflected by collecting a feedback signal of the LVDT. According to the invention, the problem of signal drift of a current load sensor in a high-pressure hydrogen environment is effectively solved, and the problem of inaccurate test results of basic mechanical properties of a material in the hydrogen environment is solved.

Apparatuses and related methods relate to a C-shaped cylindrical core for a linear variable differential transformer (LVDT) probe, and more particularly to a linear variable differential transformer (LVDT) probe that includes a plunger rod and a metal sheet formed as a cylinder having a C-shaped cross-section, the metal sheet being configured to be coupled to the plunger rod. In an exemplary example, the coupling can be an interference fit assisted by a spring retaining force of the metal sheet. The metal sheet can be stamped, formed, and applied to the plunger rod without annealing. One or more longitudinal metal sheet edges can be rounded. The C-shaped metal sheet can be welded to the plunger rod at the distal and / or proximal ends. In some examples, the longitudinal edges of the metal sheet can be welded together and / or welded to the plunger rod. The ratio of the relative magnetic permeability of the metal sheet to the plunger rod can be greater than 10. Various embodiments can advantageously reduce variability between batches and reduce the cost of manufacturing LVDTs.

A position sensing system includes a linear variable differential transformer (LVDT) to provide a first output voltage and a second output voltage. The position sensing system also includes two precision rectifiers. Each of the precision rectifiers comprises only operational amplifiers and resistors and obtains the first output voltage or the second output voltage as an input and to provide a full-wave rectified output.

This invention discloses a method and system for full-range displacement measurement using a linear variable differential transformer (LVDT) displacement sensor. The method demodulates the differential output signal of the LVDT secondary coil, simultaneously extracting amplitude and phase information. Based on pre-calibrated zero-point residual vector parameters, two displacement estimates are calculated in parallel using amplitude-domain and phase-domain solution models, respectively. A fusion weight is generated based on the current amplitude information, and the two displacement estimates are adaptively weighted and fused to obtain the final displacement measurement value. This invention utilizes the complementary characteristics of high phase sensitivity near the zero point and high amplitude linearity far from the zero point, achieving continuous and smooth switching between the two observation quantities through fusion weights. This eliminates the zero-point measurement dead zone without altering the sensor's structure, realizing continuous high-precision displacement measurement across the entire range.

The utility model provides an electromagnetic regulating valve carrying an LVDT displacement sensor, and relates to the field of regulating valves. An electromagnetic regulating valve carrying an LVDT displacement sensor comprises an LVDT sensor assembly, an upper cover, a circuit board, a lower base, an armature, a copper sleeve, a support, a magnet exciting coil, an armature core, a spring, an armature base, a valve rod and a valve body assembly. When the valve rod moves up and down, friction force basically does not exist, the up-and-down movement of the regulating valve can be achieved without overcoming redundant friction force, and a dead zone basically does not exist. And in combination with a high-precision LVDT sensor, high-precision adjustment can be realized.

The invention discloses a strut actuator, a six-degree-of-freedom secondary mirror adjusting mechanism and a control system and method thereof. The support rod actuator adopts a linear variable differential transformer (LVDT) as a sensor and comprises a primary coil, two secondary coils and an iron core. When sine wave signals are applied to the two ends of the primary coil, along with movement of the iron core, the voltage difference value induced by the two secondary coils and the displacement amount of the iron core are in a linear relation, and the linear relation is not sensitive to space irradiation. The two ends of the supporting rod actuator are connected with the upper platform and the lower platform through hooke joints, and the supporting rod actuator composed of a gear motor driving assembly and an LVDT micro-displacement sensor is restrained by a flexible rhombic support to form the micro-deformation equal-proportion amplification effect in the horizontal direction and the vertical direction. The configuration of the six support rods can effectively realize the adjustment of the six-degree-of-freedom pose of the secondary mirror, and a closed-loop six-degree-of-freedom pose control method is adopted to avoid the problem of inaccurate pose adjustment caused by the motion deviation of the support rods due to gaps and return errors brought by the motion of the stepping motor.

The utility model relates to the technical field of steam turbines, and discloses a steam turbine admission regulating valve LVDT abrasion-proof connecting device which comprises an LVDT mounting plate and a DEH admission regulating valve and further comprises a ball head rod, a connecting ball head and a ball head seat, and a fixing seat is fixedly mounted at the upper end of the LVDT mounting plate; when the connecting device is used, the connecting device has an adjusting freedom degree, and when friction is caused by axial and radial misalignment between the LVDT iron core and the sleeve, the connecting ball head and the ball head seat can rotate, swing and incline smoothly with a very small sphericity gap, so that the abrasion probability is effectively reduced, the durability is improved, and the service life of the LVDT iron core is prolonged. According to the device, lubricating grease can be rapidly injected and automatically blocked when being added, and when the lubricating grease in the rotating inner cavity is reduced, the piston presses the lubricating grease in the lubricating grease storage pipe into the rotating inner cavity, so that the lubricating grease in the rotating inner cavity is automatically supplemented, and the maintenance frequency of the ball cup and the connecting ball head is greatly reduced.

The invention relates to the technical field of structural safety monitoring, and discloses a multi-degree-of-freedom displacement monitoring system which comprises a six-degree-of-freedom loading platform which is of a Stewart structure and comprises a counter-force platform, a loading platform body and six actuators. The displacement sensor group comprises six LVDT (Linear Variable Differential Transformer) ejector rod type displacement meters which are respectively connected between the loading beam and the ground beam through spherical hinges; the data acquisition module is used for acquiring analog signals of the six LVDTs in real time and converting the analog signals into digital signals; and the coordinate conversion module is used for converting the elongation of the six LVDTs into six-degree-of-freedom displacement of a test piece control point based on an incremental kinematics transformation method. The monitoring system is compact in structure, convenient to install, high in universality and suitable for six-degree-of-freedom loading tests of various complex structures such as bridges, pier columns and cylinders, and reliable technical support is provided for structure mixing tests and quasi-static tests.

The application discloses a kind of soil centrifuge simulation marine environment pile multi-direction loading test device and method thereof, belong to civil centrifuge test technical field, the device includes: model box, square frame, sliding mechanism, at least one aluminum pipe mounting section, rotary transmission mechanism, backing plate, thrust loading mechanism, load sensor, linear variable differential transformer, multiple miniature pore pressure sensor, at least one multi-position laser displacement meter;The method is applied to the above-mentioned one kind of soil centrifuge simulation marine environment pile multi-direction loading test device;Not only can the displacement accumulation of fan foundation in the whole life cycle under the action of multi-direction, cyclic loading under multi-direction loading, stiffness variation law, but also can study the evolution law of different seabed soil settlement, consolidation and other physical and mechanical properties, and is evaluated and analyzed through multi-angle.

The utility model provides an induction coil assembly. The induction coil assembly includes a bobbin, a plurality of coils, a printed circuit board member, and a connector. The winding reel comprises a hollow channel, two end parts and a plurality of containing areas arranged outside the winding reel and located between the two end parts, wherein the containing areas are separated by separating flanges. A plurality of coils are respectively wound into the plurality of receiving regions to generate an inductive signal as a ferromagnetic core of the linearly variable differential transformer moves. The printed circuit board is fixed on the winding reel and is electrically connected with the coils so as to receive and process the induction signals. The connector is electrically connected to the printed circuit board through a wire so as to output signals from the printed circuit board. The utility model further provides a linear variable differential transformer with the induction coil assembly. According to the technical scheme, the manufacturing process is simplified, manual operation is avoided, manufacturability and reliability of products are improved, and cost is reduced.

The utility model relates to the technical field of power plants, and discloses an LVDT displacement sensor connecting structure which comprises an outer pipe, a core rod is arranged on the inner wall of the outer pipe, fixing pieces are connected to the outer surfaces of the two ends of the outer pipe in a sleeved mode, a wire protecting sleeve is arranged on the top of the outer pipe, a double-thread screw is arranged on one side of each fixing piece, and one end of each double-thread screw is in threaded connection with a mounting plate. And an anti-deviation pipe is arranged on one side of the mounting plate. According to the LVDT displacement sensor connecting structure, through cooperative arrangement of the double-thread screw, the mounting plate and the anti-deviation pipe, the device ensures that the core rod keeps linear motion in the measurement process, so that measurement errors caused by bending or deformation of the core rod are avoided, shaking and deviation of the displacement sensor in the measurement process are effectively prevented, and the measurement accuracy is improved. According to the utility model, the measuring precision and stability are improved, the stability is provided for the installation of the installation plate and the anti-deviation pipe through the arrangement of the double-thread screw, the stable installation foundation is provided through the arrangement of the installation plate, and the connection and fixation with other components are facilitated.

A thermal static calibration apparatus for testing viscous fan clutches and a method thereof is provided. The apparatus (100) includes a test rig (110) with a specialized mechanical fixture (120) designed to securely hold a half-assembled viscous fan clutch (130). This clutch comprises critical elements such as a cover (140), valve lever (150), dividing disc assembly (160), pin (170), and bimetal strip (180). Positioned orthogonally to the clutch, an air heater (190) directly heats the bimetal strip, causing controlled thermal expansion. A Linear Variable Differential Transformer (LVDT) (200) measures valve lever displacement during this process. The data recording module (210) captures temperature and deflection readings, enabling the generation of a temperature versus deflection graph. By analysing the graph's slope, the engagement temperature of the viscous fan clutch (130) is determined. Finally, a computational technique calculates the optimal pin length based on this engagement temperature.

The invention provides a special test device for an LVDT (Linear Variable Differential Transformer), and belongs to the technical field of airborne servo sensors. The device comprises a bottom plate, a supporting rod arranged on the bottom plate, a fixing and supporting assembly arranged on the supporting rod and used for fixing an LVDT stator part to be tested, a guide groove formed in the bottom plate, and a sliding block sliding on the guide groove. The coupling rod is fixed on the sliding block and is used for fixing an LVDT mover part to be tested; and the scales are engraved on the bottom plate and are used for indicating the position of the sliding block. The device is small in size and mass, high in universality, wide in application range and capable of meeting test requirements in different environments such as temperature, vibration and impact.