CN114323006A - Vibration reduction optical fiber inertial navigation system suitable for unmanned driving - Google Patents
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Abstract
The invention discloses a vibration reduction optical fiber inertial navigation system suitable for unmanned driving, which adopts a design of two cavities, and a navigation plate, an optical fiber gyroscope and an accelerometer are separately arranged, so that a vibration sensitive device and a vibration insensitive device are separated, the heat dissipation is good, and the influence of temperature on an optical fiber ring in the optical fiber gyroscope is reduced. Firstly, in practical engineering, after a system adopts a vibration damping design, the vibration damper has obvious damping effect on input vibration, and the output peak value of the fiber-optic gyroscope at high frequency is obviously reduced; then, the main reason that the vibration causes the performance reduction of the inertial navigation system is the introduction of external energy, so the mechanical environment adaptability of the instrument and the inertia combination is improved by installing a shock absorber to damp the input of the external vibration energy.
Description
Technical Field
The invention relates to the technical field of strapdown inertial navigation, in particular to a vibration reduction optical fiber inertial navigation system suitable for unmanned driving.
Background
The positioning technology of the unmanned system is the key point for solving the positioning problem. The positioning result of the vehicle body given by the positioning technology is not only applied to the global and local path planning of unmanned driving, but also influences the calculation of relevant parameters in each vehicle motion control period. The higher the unmanned level of the automobile is, the more the driving proportion of the machine is, and the influence of the positioning precision on planning decision and motion control is also increased rapidly. Therefore, solving the problem of high-precision positioning and navigation of the unmanned automobile is one of the bases for realizing correct planning decision and precise motion control.
The strapdown inertial navigation system can achieve better precision during static navigation, but the performance of the system is reduced to different degrees under the vibration condition. The influence of vibration on the performance of the inertial navigation system relates to factors of inertia devices, structures and the like, and the inertial navigation system error generated by vibration is related to the strength, frequency, vibration duration and the like of the vibration. Therefore, improving the performance of the strapdown inertial navigation system under the vibration condition is an important technical problem which is urgently needed to be solved in the model development of the strapdown inertial navigation system.
The speed rate gyroscope and the accelerometer are important sensitive elements of the strapdown inertial navigation system, the speed rate gyroscope measures the angular speed of a moving carrier, and the attitude angle of the carrier can be obtained by applying a strapdown attitude algorithm; the accelerometer measures the acceleration of the moving carrier, the speed is obtained through primary integration, and the displacement is obtained through secondary integration, so that the navigation task of the system is completed. The optical fiber inertial navigation system has the characteristic of all solid state, and can be miniaturized and has better stability compared with a laser gyro inertial navigation system. The vibration resistance of the fiber-optic gyroscope and the combination in the vibration process has great influence on navigation calculation, and the main reason of the performance reduction of the inertial navigation system caused by vibration is the introduction of external energy, so that the input of the external vibration energy is attenuated to become the most direct means for improving the mechanical environment adaptability of the instrument and the inertia combination, and the simplest and most common method in engineering is realized by installing a vibration absorber. In terms of physics, the vibration absorber is a low-pass filter, is arranged on a mounting base and other parts of equipment, forms a vibration absorbing system with the equipment, blocks high-frequency stress transmitted to the equipment (motion vibration isolation) or foundation (force vibration isolation) from the outside, and attenuates the transmission of external high-frequency energy.
In order to better meet the navigation requirement of an unmanned system, the inertial navigation system has the structural requirement of light and small size. The existing light and small vehicle-mounted strapdown inertial navigation system mainly takes MEMS as a main part, but the gyro precision is in the magnitude of several degrees/h, the accelerometer precision is in several mg, the higher and higher positioning navigation requirements of unmanned driving cannot be met, and the MEMS inertial navigation system is greatly influenced in a vibration environment.
Therefore, how to reduce the vibration in the unmanned fiber inertial navigation system and improve the accuracy of positioning and navigation is a problem that needs to be solved urgently by those skilled in the art.
Disclosure of Invention
In the actual engineering, the system adopts sub-cavities, a power supply and a navigation board are placed in one cavity, a light source, an accelerometer and a fiber optic gyroscope are placed in the other cavity, and signals are connected and transmitted through a connector; according to the calculated vibration reduction efficiency, the vibration reduction design of the vibration reducer arranged at eight points in the cavity is determined, the vibration reducer can deal with multi-directional vibration, the attenuation effect on input vibration is obvious, the output peak value of the gyroscope at a high frequency position is obviously reduced, the sensitivity of a fiber ring and an accelerometer in the fiber optic gyroscope to vibration is effectively reduced, and the positioning and attitude determination precision is ensured. The main reason that the vibration causes the performance reduction of the inertial navigation system is the introduction of external energy, so the mechanical environment adaptability of the instrument and the inertia combination is improved by installing a vibration damper to damp the input of the external vibration energy.
In order to achieve the purpose, the invention adopts the following technical scheme:
a vibration reduction optical fiber inertial navigation system suitable for unmanned driving comprises a shell, wherein the interior of the shell is divided into a first cavity and a second cavity; an IMU assembly, a light source and a vibration absorber are arranged in the first chamber, and the IMU assembly comprises a fiber optic gyroscope and an accelerometer; a navigation board, an interface board and a power supply module are arranged in the second chamber; the light source, the fiber-optic gyroscope, the accelerometer and the power supply module are connected with the navigation board through the interface board; the light source illuminates the fiber optic gyroscope through a coupler. The coupler divides the light source into three paths of light and provides optical signals for a fiber ring in the fiber-optic gyroscope; the interface board is provided with a connector which is connected with an external device.
The vibration damper, the fiber optic gyroscope and the accelerometer are arranged in the same cavity, the fiber optic gyroscope and the accelerometer are sensitive devices and directly damp vibration of the sensitive devices, and compared with the vibration damper arranged outside the shell and needing to bear the weight of the whole system, the vibration damper arranged in the cavity bears light weight, and the vibration damper can be made to be very small.
Preferably, the navigation panel comprises a processor and a controller; the controller is responsible for controlling the internal interface, the internal interface comprises a data acquisition interface, an internal control interface and a temperature monitoring module, the data acquisition interface and the internal control interface are connected with the processor, the temperature monitoring module acquires temperature data of the fiber-optic gyroscope and the accelerometer, output signals of the fiber-optic gyroscope and the accelerometer are related to temperature, and errors caused by the temperature signals are compensated; the processor is responsible for external interface control, is connected with the fiber-optic gyroscope, the accelerometer and the upper computer through the interface board, collects gyroscope data and acceleration data, transmits the gyroscope data and the acceleration data to the controller through the collected data interface for calculation, and transmits the gyroscope data and the acceleration data to the upper computer through the internal control interface.
Preferably, the distance between the power module and the inner wall of the housing is smaller than a set threshold, and the threshold may be 1 cm. The power module is close to the shell and is beneficial to heat dissipation.
Preferably, an air isolation layer is reserved between the shell and the fiber optic gyroscope, is located between the shell and the IMU assembly and is formed through a damper, and therefore direct heat conduction can be effectively prevented.
Preferably, the light source provides an interference light path for the fiber optic gyroscope, in which vibration may cause the fiber to periodically stretch or squeeze, and if the stretching or squeezing is asymmetric with respect to a midpoint of the interference light path, a periodic phase modulation is introduced between two beams of light participating in interference:
δ＝Δφvcos(ωvt+ε)
wherein, isvIs the amplitude, omega, of the phase modulationv＝2πfv，fvIs the vibration frequency, and epsilon is an arbitrary initial phase;
under the vibration condition, the optical fiber inertial navigation system can generate angular motion with the same vibration frequency for various reasons, the output of the optical fiber gyroscope can truly reflect the angular motion, so that the optical fiber gyroscope is represented as a phase modulation, the expression is the same as that of the formula, under the condition that the input angular speed is a simple alternating current function, the ideal output of the optical fiber gyroscope does not generate any direct current term or zero offset error, but in the actual optical fiber gyroscope, other additional vibration effects can be synchronously generated under the vibration condition, and by combining the two phase modulation effects, a direct current error term (or a positive error term) can be generated, and the direct current error term is represented as that the zero of the gyroscope generates offset.
Preferably, the supporting structure of the vibration damper is made of rubber materials, and the vibration transmissibility of the supporting structure is as follows:
wherein f is the frequency of the vibratory force; f. of0Is the natural frequency of the support structure; k is the dynamic stiffness of the shock absorber; g is the acceleration of gravity; w is the mass of the object; ξ is the damping ratio of the shock absorber; the damping ratio of the rubber shock absorber ranges from 0.02 to 0.15;
because the effect of the vibration damper is related to the mass of the vibration-isolated equipment and the rigidity and the damping of a vibration-isolating system, the vibration-isolating design needs to determine the parameters of the vibration damper according to the frequency of a vibration source and a vibration-isolating target, the required natural frequency of the vibration damper is calculated according to a vibration-isolating theoretical formula, the frequency of the vibration source and the vibration-isolating target, then the rigidity of the vibration damper can be calculated according to the mass of the vibration-isolated equipment and the natural frequency of the vibration damper, when other conditions are determined, the smaller the rigidity of the vibration damper is, namely the softer the vibration damper is, the better the vibration-isolating effect is, but the shock resistance of the system can be reduced while the vibration-isolating effect is improved; the amplification factor is a way to measure the damping performance by describing the frequency ratio;
when frequency ratio (f/f)0) When the value is 1, the vibration transfer rate is the maximum, the force transfer has an amplification phenomenon, and the whole inertial navigation system is in a dangerous resonance state; when the frequency ratio is equal to
When the vibration isolation effect is achieved, the transmission rate is equal to 1, and the vibration isolation effect is not achieved, and the transmission rate is not amplified; when the frequency ratio is greater than
When the transmission rate is less than 1, the inertial navigation system has vibration isolation effect, and the transmission rate T increases along with the frequency ratioaDecrease means better damping effect, but (f/f)0) When the frequency ratio of the selected shock absorber is in a general range of 2-5, the shock absorption efficiency curve almost tends to be horizontal, which shows that the shock absorption effect is not remarkably improved, the softer the elastic supporting structure is, the larger the shaking space required by the supporting structure is, the worse the stability of the inertial navigation system is, and the lower the shock resistance is;
the damping efficiency is about 80-95%, the amplification factor is not more than 5 and is close to 3, the damping effect is good, and the shock resistance of the system can not be reduced.
Preferably, a plurality of groups of the vibration dampers are installed in the first chamber, and the vibration dampers are arranged in eight points in space. The vibration absorber adopts an SAW-7 vibration absorber, a plurality of vibration absorbers are arranged at eight points in the space of the first chamber to form an eight-point vibration absorber, the gyration radius of the first chamber is small, the natural frequency of angular vibration of the vibration absorber is low, and the distortion degree is increased at high frequency; and because the first chamber space is smaller, and a plurality of groups of vibration absorbers are needed, the size precision of the vibration absorbers has larger influence on the installation precision of the fiber-optic gyroscope and the accelerometer sensitive device, the SAW-7 vibration absorbers are adopted, the space eight-point layout is adopted, the total load is 2.1kg, the installation screw M4 has the amplification factor not more than 5 and close to 3, and the resonant frequency is divided into 80Hz and 130 Hz. Determining eight-point vibration reduction according to the internal space structure of the optical fiber inertial navigation system, wherein the installation position is selected according to the size of the selected optical fiber gyroscope and accelerometer and the reserved space; the vibration reduction efficiency is obtained according to simulation calculation and actual test; the final effect of vibration reduction is that simulation and actual measurement are carried out to verify according to the built structure.
Preferably, the power module is close to the shell, so that heat dissipation is facilitated, the controller of the navigation board is mainly responsible for internal interface control, the controller comprises a data acquisition interface, an internal control interface and temperature monitoring, and the processor of the navigation board is mainly responsible for external interface control; the power module adopts 18-36V power supply, has output of plus-minus 5V, plus-minus 15V and plus-minus 3.3V, and plus-minus 15V and plus-minus 5V give the accelerometer power supply, and plus-minus 5V and plus-minus 3.3V give the navigation board power supply, and plus-minus 5V and plus-minus 3.3V give the fiber optic gyro power supply, the fiber optic gyro with the navigation board adopts 3.3V power supply, reduces the consumption and generates heat.
According to the technical scheme, compared with the prior art, the vibration reduction optical fiber inertial navigation system applicable to unmanned driving is disclosed, the structure is optimized, the two-cavity design is adopted, the navigation plate, the optical fiber gyroscope and the accelerometer are separately arranged, so that the vibration sensitive device and the vibration insensitive device are separated, the heat dissipation is good, and the influence of temperature on an optical fiber ring is reduced; in order to reduce the influence of vibration on the optical fiber ring of the optical fiber gyroscope, an air interlayer is reserved between the optical fiber gyroscope and the air interlayer for placing heat to be directly conducted; the optical fiber gyroscope and the quartz accelerometer have high precision and reliability; the shell is made of aluminum alloy materials, so that the weight is lighter, and the heat dissipation is excellent; a processor and a controller of the navigation board core adopt a piece of FPGA and DSP, the working reliability is high, the high-temperature anti-vibration device is adopted, meanwhile, the heating device is separately placed during the circuit layout on the navigation board, the heat dissipation module, the vehicle-mounted vibration and the high-low temperature working environment are fully considered, and the real-time measurement precision of various navigation data is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic diagram of an overall structure of an inertial navigation system according to the present invention;
FIG. 2 is a schematic diagram illustrating an explosive structure of an inertial navigation system according to the present invention;
FIG. 3 is a side view of the shock absorber provided in accordance with the present invention;
FIG. 4 is a top view of the shock absorber provided in accordance with the present invention;
FIG. 5 is a schematic diagram of an inertial navigation system accelerometer according to the present invention showing z-axis before, during and after vibration;
FIG. 6 is a schematic diagram of an inertial navigation system fiber-optic gyroscope before, during and after x, y and z axis vibration according to the present invention;
FIG. 7 is a flow chart of a vibration reduction design of an inertial navigation system according to the present invention.
In the drawings: 1-housing, 11-IMU assembly, 12-vibration absorber, 121-support structure, 122-screw hole, 123-central through hole, 13-navigation plate, 14-interface plate, 15-power module, 16-front panel assembly, 2-housing cover, 3-bottom cover.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention discloses a vibration reduction optical fiber inertial navigation system suitable for unmanned driving, which comprises a shell 1, wherein the interior of the shell 1 is divided into a first chamber and a second chamber, an IMU (inertial measurement Unit) component 11, a light source and a vibration reducer 12 are arranged in the first chamber, and the IMU component 11 comprises an optical fiber gyroscope and an accelerometer; the second chamber is internally provided with a navigation board 13, an interface board 14 and a power supply module 15; the light source, the fiber-optic gyroscope, the accelerometer and the power supply module 15 are connected with the navigation board 13 through the interface board 14.
In order to further optimize the above technical solution, the navigation board 13 includes a processor and a controller; the controller is responsible for controlling the internal interface and comprises a data acquisition interface, an internal control interface and a temperature monitoring module; the processor is responsible for external interface control, is connected with the fiber-optic gyroscope, the accelerometer and the upper computer through the interface board 14, collects gyroscope data and acceleration data, transmits the gyroscope data and the acceleration data to the controller for calculation, and then transmits the gyroscope data and the acceleration data to the upper computer through the interface board 14.
In order to further optimize the above technical solution, the distance between the power module 15 and the inner wall of the housing 1 is smaller than a set threshold, and the threshold may be set to 1 cm. The power module 15 is mounted close to the housing 1, which facilitates heat dissipation.
In order to further optimize the technical scheme, an air interlayer is reserved between the optical fiber gyroscope and the optical fiber gyroscope to prevent heat from being directly conducted.
In order to further optimize the technical scheme, a front panel assembly 16 is further arranged, is connected with an external direct current power supply and is connected with an internal interface board inside the shell 1, and transmits signals of the vibration reduction fiber inertial navigation system.
Examples
The design process of the vibration reduction optical fiber inertial navigation system comprises the following steps:
1. structural design
As shown in fig. 1, the inertial measurement unit adopts a three-axis integrated fiber optic gyroscope and a three-axis integrated quartz accelerometer, and takes the resonance influence of system components into consideration, and adopts a dual-cavity design, the navigation board 13, the interface board 14 and the power module 15 are placed in a cavity, and the interface board 14 is provided with a connector; the IMU assembly 11 (including fiber optic gyroscopes, accelerometers, etc.) is a vibration sensitive assembly, placed in another cavity in conjunction with an internal damper 12, as shown in figure 2. The power module 15, the navigation board 13 and the IMU assembly 11 are connected through a connector of the interface board 14; the navigation board 13 receives and resolves data of the fiber-optic gyroscope and the accelerometer, and the power supply module 15 converts external power supply into voltage required by the fiber-optic inertial navigation system and provides stable power supply with small ripples.
2. Vibration damping design
The whole inertial navigation system is provided with a module which is easy to be interfered by vibration, wherein the fiber-optic gyroscope is most sensitive to vibration, the design of a vibration damping structure is mainly considered, an external vibration damping design and an internal vibration damping design are considered, the strapdown inertial combination whole vibration damping measure is considered as external vibration damping, the instrument vibration damping of a gyroscope (accelerometer) is considered as internal vibration damping, and the two vibration damping methods are compared. The overall stiffness of shock absorber 12 should meet the transmissibility requirements; the total damping of the shock absorber 12 should meet both the transmissibility and the amplitude requirement through the resonance zone; the size of the damper 12 cannot be larger than a given spatial dimension; the material and type of the damper 12 should be compatible with the load characteristics, the type of excitation, and the given operating environment. The vibration absorber 12 is installed in the combined axial direction to isolate high-frequency components in external vibration, and the input of external high-frequency energy can be obviously attenuated. The problem that the gyro is greatly influenced by external input energy in the vibration process is solved to a certain extent. By adopting internal vibration reduction measures, the installation and the use of the vibration absorber 12 need to be strictly controlled, and the selection of the pretightening force for installing the vibration absorber 12 by screwing the screw and the influence of the size of the screw on the vibration reduction effect are great.
(1) In the interference optical path of the fiber optic gyroscope, vibration causes the fiber to periodically stretch or squeeze, and if the stretching or squeezing is asymmetric with respect to the midpoint of the interference optical path, a periodic phase modulation is introduced between the two beams participating in the interference:
δ＝Δφvcos(ωvt+ε)
wherein, isvIs the amplitude, omega, of the phase modulationv＝2πfv，fvIs the vibration frequency, and epsilon is an arbitrary initial phase;
under the vibration condition, the angular motion with the same vibration frequency can be generated due to various reasons, the output of the fiber-optic gyroscope can truly reflect the angular motion, so that the fiber-optic gyroscope is represented as a phase modulation, the expression is the same as the expression in the formula, under the condition that the input angular velocity is a simple alternating current function, the ideal output of the fiber-optic gyroscope can not generate any direct current term or zero offset error, but in the actual fiber-optic gyroscope, under the vibration condition, other additional vibration effects can be synchronously generated, and in combination with the two phase modulation effects, a direct current error term (or a positive error term) can be generated, and the direct current error term (or the positive error term) is represented as the zero offset of the gyroscope.
(2) For a viscous damping system, such as the support structure 121 of the rubber damper 12, the vibration transmissibility is:
wherein f is the frequency of the vibratory force in Hz; f. of0Is the natural frequency of support structure 121, also in Hz; k is the dynamic stiffness of the shock absorber 12, 10N/cm; g is the acceleration of gravity, W is the mass of the object in kg; xi is the damping ratio of the shock absorber 12, and the damping ratio of the rubber shock absorber 12 is (0.02-0.15);
when frequency ratio (f/f)0) When the vibration transmission rate is 1, the vibration transmission rate is the maximum, the force transmission has an amplification phenomenon, and the whole system is in a dangerous resonance state; when the frequency ratio is equal to
When the vibration isolation effect is achieved, the transmission rate is equal to 1, and the vibration isolation effect is not achieved, and the transmission rate is not amplified; when the frequency ratio is greater than
When the transmission rate is less than 1, the system has vibration isolation effect, and the transmission rate T is increased along with the increase of the frequency ratioaDecrease means better damping effect, but (f/f)0) When the damping efficiency curve is more than 5, the damping efficiency curve almost tends to be horizontal, which shows that even if the damping system is designed to be softer, the damping effect cannot be expected to be remarkably improved. The softer the elastic support structure 121, the more sloshing space the system requires, the less stable the system, and the impact resistanceThe capacity decreases, so generally:
at the moment, the vibration reduction efficiency is about (80-95)%, the amplification factor of the invention is not more than 5 and is close to 3, the vibration reduction effect is good, and the shock resistance of the system is not reduced, as shown in figures 5 and 6, figure 5 shows a graph before, during and after the z-axis vibration of an accelerometer of the inertial navigation system, the abscissa shows time, and the ordinate shows acceleration with the unit of m/s2(ii) a FIG. 6 shows x, y and z axis before, during and after vibration of the fiber-optic gyroscope of the inertial navigation system, the abscissa represents time, and the ordinate represents angular increment of the fiber-optic gyroscope in degrees/h.
(3) Water or ground vehicles (or weaponry) are typically dominated by random vibrations with a tolerance frequency below 500 Hz. As shown in fig. 7, the design process of vibration reduction of the inertial navigation system includes an external vibration reduction design and an internal vibration reduction design, the external vibration reduction design is to reduce the overall vibration of the inertial navigation system, the inertial navigation system is placed on a vibration reduction table or a vibration reducer 12 is installed on the inertial navigation system, the internal vibration reduction design is to separate the fiber-optic gyroscope and the accelerometer from the circuit board and the power module 15, and two-cavity design is performed, so as to reduce the influence of vibration on the fiber-optic ring of the fiber-optic gyroscope, and an air interlayer is left between the fiber-optic gyroscope and the fiber-optic gyroscope to prevent direct heat conduction. The advantage of the internal damping measure of placing the damper 12 in the cavity is that the damping is directly performed on the sensitive device, the effect is significant, and the damper 12 can be made very small due to the light weight of the load. The internal vibration reduction measure is characterized in that the cavity has small turning radius and low natural frequency of angular vibration, so that the distortion degree is increased at high frequency; and the installation space is generally smaller, and multiple sets of shock absorbers 12 are needed, so the dimensional accuracy of the shock absorbers 12 has a greater influence on the installation accuracy of sensitive devices, the present embodiment fully considers the above problems, the structural design of the shock absorbers 12 is as shown in fig. 3 and 4, the shock absorbers 12 are 35mm long and 10mm high, the center distance of the screw holes 122 on both sides is 29mm, the outer diameter of the supporting structure 121 is 20mm, the inner diameter is 13mm, the diameter of the central through hole 123 is 4.3mm, the SAW-7 shock absorbers are adopted, the space eight-point layout is adopted, the total load is 2.1kg, and the installation screws M4 are adopted. The amplification factor is not more than 5 and is close to 3, and the resonance frequency is divided into 80Hz and 130 Hz. As shown in fig. 2, the inertial navigation system includes a housing 1, a housing cover 2 and a bottom cover 3, an IMU assembly 11 including three accelerometers and three fiber optic gyroscopes, a vibration absorber 12, a navigation plate 13, an interface board 14 provided with connectors, a power module 15, a light source and a front panel assembly 16 are installed in the housing 1, and the power module 15 is close to the housing 1, which is beneficial to heat dissipation. The DSP in the navigation board 13 is mainly responsible for internal interface control. The system comprises a data acquisition interface, an internal control interface and a temperature monitoring module, wherein the FPGA in the navigation board 13 is mainly responsible for external interface control; the power module 15 supplies power by 18-36V, the power module 15 has outputs of plus-minus 5V, plus-minus 15V and plus-minus 3.3V, and supplies power for the meter, the navigation board 13 and the gyroscope respectively, and the gyroscope and the navigation board 13 supply power by 3.3V, so that power consumption and heating are reduced. And realizing the vibration reduction design of the optical fiber inertial navigation system for the unmanned vehicle according to the design.
3. Signal stream design
Output signals of the fiber-optic gyroscope and the accelerometer are transmitted to the navigation board 13 through the interface board 14 to be collected by the FPGA, the signals are calculated by the DSP, and then the data are output to an external upper computer through an external connector by the interface board 14, wherein the navigation board 13 and the fiber-optic gyroscope are powered by 3.3V.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. The vibration reduction optical fiber inertial navigation system suitable for unmanned driving is characterized by comprising a shell, wherein the interior of the shell is divided into a first cavity and a second cavity; an IMU assembly, a light source and a vibration absorber are arranged in the first chamber, and the IMU assembly comprises a fiber optic gyroscope and an accelerometer; a navigation board, an interface board and a power supply module are arranged in the second chamber; the light source, the fiber-optic gyroscope, the accelerometer and the power supply module are connected with the navigation board through an interface board; the light source illuminates the fiber optic gyroscope through a coupler.
2. The vibration damped fiber optic inertial navigation system for unmanned aerial vehicle of claim 1, wherein the navigation pad comprises a processor and a controller; the controller is responsible for controlling the internal interface, the internal interface comprises a data acquisition interface, an internal control interface and a temperature monitoring module, and the data acquisition interface and the internal control interface are connected with the processor for control; the temperature monitoring module acquires temperature data of the fiber-optic gyroscope and the accelerometer; the processor is responsible for external interface control, is connected with the fiber-optic gyroscope, the accelerometer and the upper computer through the interface board, collects gyroscope data and acceleration data, transmits the gyroscope data and the acceleration data to the controller through the collected data interface for calculation, and transmits the gyroscope data and the acceleration data to the upper computer through the internal control interface.
3. The vibration-damped fiber optic inertial navigation system according to claim 1, wherein the distance between the power module and the inner wall of the housing is less than a set threshold.
4. The system of claim 1, wherein an air barrier is left between the fiber optic gyroscope and the housing and between the housing and the IMU assembly, and is formed by a damper.
5. The vibration-damped fiber optic inertial navigation system suitable for unmanned aerial vehicle of claim 1, wherein the support structure of the vibration damper is made of rubber material, and the vibration transmissibility is as follows:
wherein f is the frequency of the vibratory force; f. of0Is the natural frequency of the support structure; k is the dynamic stiffness of the shock absorber; g is the acceleration of gravity; w is the mass of the object; ξ is the damping ratio of the shock absorber.
6. The unmanned vibration-damped fiber optic inertial navigation system of claim 1, wherein said first chamber houses a plurality of sets of said vibration dampers, said vibration dampers being arranged in eight points in space.
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