Temperature field control method suitable for inertial measurement system

Abstract

The invention discloses a temperature field control method suitable for an inertial measurement system, which comprises the following steps of: dividing the system into two stages of temperature fields between an inner spherical cover and an outer spherical cover and a table body from outside to inside by adopting a multi-stage partition temperature field control strategy, and performing partition temperature control; in the first-stage temperature field control, a fuzzy control method is adopted to calculate a corresponding heating sheet heating duty ratio and a fan rotating speed control instruction, and the influence caused by external environment temperature fluctuation is effectively restrained; in the second-stage temperature field control, disturbance of each temperature control point is estimated by adopting an expansion observer and is compensated to a heating resistor heating duty ratio control instruction calculated based on a PID control method, and the influence caused by a complex coupling heat source in the system is effectively inhibited; compared with other inertial measurement system temperature field control methods, the real-time control of the system temperature field is realized, the inertial instrument measurement error caused by the fluctuation of the temperature field is reduced, the measurement precision and long-term stability of the inertial measurement system are further improved, and the method has important significance for improving the long-term navigation precision.

Description

Technical Field

[0001] The invention relates to a temperature field control method applicable to an inertial measurement system, in particular to a temperature field control method applicable to a platform-type inertial measurement system, and belongs to the technical field of inertial measurement systems. Background Art

[0002] The inertial measurement system has the advantages of higher navigation accuracy and less data calculation. It is widely used in long-duration high-precision inertial navigation fields such as marine resource exploration and aerospace. However, since the working accuracy of the inertial instruments (gyroscopes and accelerometers) it contains is temperature sensitive, the navigation accuracy of the inertial measurement system is easily affected by temperature. Changes in the internal temperature of the system will cause fluctuations in the working temperature of the gyroscope and accelerometer, thereby inducing measurement errors and affecting the accuracy of the inertial measurement system. Therefore, high-precision inertial measurement system temperature field control is the premise and guarantee for realizing a high-precision inertial platform.

[0003] During the operation of the inertial measurement system, the temperature field inside it is affected by many factors. First, the power consumption of the inertial instrument, torque motor, angle sensor and related circuit modules in the system changes with the working state; at the same time, the geometric relationship between the various frames changes with the movement of the carrier, which will cause the system's outward heat transfer coefficient to change; in addition, the ambient temperature outside the inertial measurement system also changes. The coupling of multiple heat sources and the change of the external ambient temperature make the internal temperature field of the inertial measurement system complex and changeable, which has a great impact on the working temperature of the inertial instrument.

[0004] At present, most platform-type inertial measurement systems use individual temperature control for each inertial measurement instrument to ensure the measurement accuracy of the inertial instrument. However, factors such as the unclear coupling relationship between multiple heat sources within the inertial measurement system and the obvious influence of external environmental temperature fluctuations have led to unsatisfactory instrument temperature control accuracy, resulting in large fluctuations in the instrument's operating temperature, which still has a significant impact on the inertial instrument's measurement results. Therefore, reducing the temperature fluctuation within the platform-type inertial measurement system, achieving high-precision control of the temperature field within the system, ensuring the stability of the operating temperature of each inertial instrument, and fundamentally ensuring the measurement accuracy of the inertial instrument have become urgent engineering issues to be solved.

[0005] In order to meet the requirements of high-precision temperature field control for high-precision inertial measurement systems, it is necessary to design a temperature field control method suitable for inertial measurement systems, which can actively perform multi-level partition temperature field control on the temperature field in the system, effectively reduce the temperature gradient in the system, and make the temperature field inside the system stable and uniform. It can suppress the influence of internal complex heat source coupling and external environmental temperature changes, avoid the fluctuation of temperature field in the system, and cause the measurement accuracy of inertial instruments to decrease, thereby effectively improving the accuracy of platform-type inertial measurement systems and their adaptability in complex environments. Summary of the invention

[0006] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide a temperature field control method suitable for an inertial measurement system, to avoid the influence of the complex heat source coupling inside the inertial measurement system and the temperature change of the external environment on the internal temperature field of the system, and to realize the internal temperature field control of the inertial measurement system.

[0007] The technical solution of the present invention is: in the first aspect, an inertial measurement system is provided, including: an inertial measurement system tooling, an outer ball cover, a convection fan, an inner ball cover, a table support transfer mechanism, a table, an inertial instrument assembly, a heating plate, a heating resistor, a temperature sensor and an external control unit, wherein:

[0008] The inner ball cover is located inside the outer ball cover, the platform is located inside the inner ball cover, and the outer ball cover, the inner ball cover and the platform are all spheres and share a common center.

[0009] One end of the table body supporting transfer mechanism passes through the outer spherical cover and the inner spherical cover in sequence and is fixed on the table body, and the other end is connected to the inertial measurement system tooling;

[0010] The inertial instrument assembly is placed inside the platform; the heating resistor is attached to the inertial instrument assembly to control the temperature of the inertial instrument assembly in a stable state;

[0011] The inner ball cover is provided with air holes for gas circulation; two convection fans are symmetrically installed at the upper left and upper right of the inner ball cover respectively, for driving the air inside the inner ball cover to flow upward into the interlayer between the outer ball cover and the inner ball cover;

[0012] A plurality of heating plates are distributed around the air holes below the inner spherical cover to heat the gas flowing from the interlayer into the inner spherical cover;

[0013] Multiple temperature sensors are distributed around two convection fans and several heating plates to monitor real-time temperature;

[0014] The external control unit receives the temperature measured by the temperature sensor in real time, performs temperature field control calculations, and then sends control instructions to the heating plate and the convection fan respectively to adjust the heating duty cycle of the heating plate and the fan speed.

[0015] Preferably, the areas around the two convection fans are defined as the air outlet areas, i.e., the areas where the air flows out of the inner spherical cover; and the areas around the plurality of heating plates are defined as the air inlet areas, i.e., the areas where the air flows into the inner spherical cover;

[0016] Based on the requirements of multi-level partition temperature field control, the inertial measurement system is divided into: first-level temperature field and second-level temperature field; among them:

[0017] The first-level temperature field is the temperature field of the interlayer between the outer ball cover and the inner ball cover, which is divided into two areas: the air outlet area and the air inlet area, and the temperature is controlled by the convection fan and the heating plate;

[0018] The second-level temperature field is the temperature field inside the platform, and the temperature is controlled by heating resistors.

[0019] Preferably, the air inside the system starts from the platform body, flows upward and leaves the inner spherical cover, flows into the interlayer of the double-layer spherical cover, flows from top to bottom in the interlayer, flows into the inner spherical cover from the bottom, and finally flows to the platform body. On the whole, the air inside the inertial measurement system flows in the shape of a magnetic field;

[0020] Through the flow of air inside the inertial measurement system, the heat flux emitted by the platform is sent into the interlayer of the double-layer ball cover through the convection fan, and then conducted to the external environment of the inertial measurement system by the outer ball cover.

[0021] In a second aspect, a temperature field control method applicable to an inertial measurement system is provided, comprising:

[0022] S1. Real-time measurement of the internal temperature field state of the inertial measurement system through the arranged temperature sensors;

[0023] S2. Based on the first-level temperature field state of the inertial measurement system, the heating duty cycle control instruction H of the heating plate in the outlet area of ​​the first-level temperature field is obtained by the fuzzy control method. 出 , heating duty ratio control command H of the heating plate in the air inlet area 进 and fan speed control instruction F;

[0024] S3, based on the state of the second-stage temperature field of the inertial measurement system, the disturbance z of each temperature control point in the second-stage temperature field is estimated by the extended observer 2j ; The temperature control point is the location of the temperature sensor;

[0025] S4, based on the state of the second-stage temperature field and the estimated disturbances of each temperature control point, calculate the control instruction u of the heating duty cycle of each heating resistor in the second-stage temperature field 2j ;

[0026] S5. According to the control instructions of each level of temperature field, the heating duty ratio of the heating plate and the heating resistor and the fan speed are adjusted;

[0027] S6. Return to step S1 and repeat the iteration to realize the temperature field control of the inertial measurement system.

[0028] Preferably, in S2, the heating duty ratio H of the heating plate in the air outlet area is controlled by calculating the first-level temperature field by a fuzzy control method. 出 , Heating duty ratio H of the heating plate in the air inlet area 进The method of controlling the fan speed command F is:

[0029] Calculate the outlet temperature error e of the outlet area of ​​the first-level temperature field 出 (t i ) and outlet temperature error change rate Δe 出 (t i );

[0030] Calculate the inlet temperature error e of the inlet area of ​​the first-stage temperature field 进 (t i );

[0031] According to the outlet temperature error e 出 (t i ), temperature error of air inlet area e 进 (t i ) and the outlet temperature error change rate Δe 出 (t i ) value, and divide the fuzzy interval for each parameter;

[0032] Formulate a fuzzy control rule table based on the fuzzy interval;

[0033] By locating the outlet temperature error e of the outlet area 出 (t i ) and the outlet temperature error change rate Δe 出 (t i ) in the fuzzy interval, and look up the table to obtain the heating duty ratio H of the heating plate in the outlet area in the current state. 出 and fan speed F;

[0034] Temperature error e of the air inlet area 进 (t i ) in the fuzzy interval, look up the table to obtain the heating duty ratio H of the heating plate in the air inlet area 进 .

[0035] Preferably, the outlet temperature error e 出 (t i ), air inlet temperature error e 进 (t i ) and the outlet temperature error change rate Δe 出 (t i ) are:

[0036] e 出 (t i )=T m出 -T d出 ;

[0037]

[0038] e进 (t i )=T m进 -T d进 ;

[0039] Among them, T d出 is the reference temperature of the air outlet area, T m出 is the average value of the measured temperature at each point in the outlet area, T d进 is the reference temperature of the air inlet area, T m进 is the average value of the measured temperature at each point in the air inlet area, and Δt is the sampling period.

[0040] Preferably, the fuzzy control rule table includes an air outlet area fuzzy control rule table and an air inlet area fuzzy control rule table, wherein:

[0041] When formulating the fuzzy control rule table for the air outlet area, the air outlet temperature error e is also considered. 出 (t i ) and the outlet temperature error change rate Δe 出 (t i ): When Δe 出 (t i ) remains unchanged, and e 出 (t i ) changes from negative to positive, the duty cycle of the heater and the fan speed gradually decrease; when e 出 (t i ) remains unchanged, and Δe 出 (t i ) changes from a negative value to a positive value, the duty cycle of the heater remains unchanged, while the fan speed gradually increases according to the situation; for the heater duty cycle and fan speed of the outlet area in each fuzzy interval, a corresponding heating duty cycle control instruction H for the heater in the inlet area is formulated. 出 and fan speed control instruction F;

[0042] When formulating the fuzzy control rule table for the air inlet area, the temperature error e of the air inlet area is considered. 进 (t i ): when e 进 (t i ) changes from negative to positive, the heating duty ratio H of the heating plate in the air inlet area 进 Gradually reduce; for each fuzzy interval of the air inlet area heating plate duty cycle, formulate the corresponding air inlet area heating plate heating duty cycle control instruction H 进 .

[0043] Preferably, when adjusting the fan speed, in order to ensure uniform temperature inside the system and minimize the impact of heat convection, the fan must keep working and maintain at least the minimum speed F min .

[0044] Preferably, the disturbance z of each temperature control point in the second-stage temperature field is estimated by an extended observer 2j , specifically:

[0045] Calculate the temperature error of each temperature measurement point of the second-stage temperature control as e 2j (t i )=T m2j -T d2j ;

[0046] Estimating the total disturbance of uncertainty and cross-coupling interference of heat sources acting on the system, the linear extended observer equation is:

[0047]

[0048] Where, j=1,...,n is the number of the multi-channel temperature sensor, T d2j and T m2j The reference temperature and the measured temperature of each point are set respectively for each point of the platform; 1j is the temperature of the temperature sensor estimated by the observer, z 2j is the total disturbance of the temperature sensor estimated by the observer, u 2j is the input of the heating duty cycle of the heating resistor corresponding to number j, and β1 and β2 are the observer gains.

[0049] Preferably, the control instruction u of the heating duty ratio of each heating resistor in the second-stage temperature field is 2j for:

[0050]

[0051] Among them, k pj , k ij , k dj are the PID controller parameters.

[0052] Compared with the prior art, the present invention has the following advantages:

[0053] (1) The existing temperature field control method of the inertial measurement system is sensitive to the temperature fluctuation of the external environment. The temperature field inside the system is seriously affected by the temperature change of the external environment. The method of the present invention adopts a fuzzy control method with good robustness through a multi-level partition temperature field control strategy. It can quickly heat up and adjust the heating duty cycle of the heating plate and the fan speed level step by step to avoid the impact on the power supply system and the electromagnetic interference to the surrounding devices. The influence of the external environment temperature fluctuation on the internal temperature field of the system is weakened layer by layer, and the influence of the external environment temperature fluctuation can be well suppressed.

[0054] (2) Existing temperature field control methods for inertial measurement systems give little consideration to the impact of complex coupling of internal heat sources on the temperature field or are too complex, making them difficult to apply in engineering. The method of the present invention regards the internal heat source coupling and unknown interference of the system as the total disturbance of the system, and observes and compensates them through an easily implementable linear expansion observer, thereby achieving multi-input and multi-output decoupling of the inertial measurement system temperature and improving the anti-interference ability.

[0055] (3) The existing temperature field control method of the inertial measurement system is sensitive to acceleration, and the temperature field inside the system is seriously affected by acceleration. The method of the present invention ensures constant air convection and the temperature of the air entering the inner ball cover through the first-level temperature field control, establishes a stable temperature field around the platform, and greatly weakens the influence of acceleration.

[0056] (4) Compared with the existing temperature field control method of the inertial measurement system, the method of the present invention can be expanded to three levels, four levels, etc. according to the specific structure of the inertial measurement system. At the same time, the number of partition control and the number of temperature control channels can also be expanded. It can also be extended to inertial measurement devices that also have a multi-layer cover structure and high overload application scenarios, and has good economy and universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A flow chart of a temperature field control method applicable to an inertial measurement system of the present invention;

[0058] Figure 2 A cross-sectional schematic diagram of an inertial measurement system provided by an embodiment of the present invention;

[0059] Figure 3 A schematic diagram of multi-level partition temperature field control of an inertial measurement system provided by an embodiment of the present invention;

[0060] Figure 4 This is a diagram of the temperature field control results of the inertial measurement system provided by an embodiment of the present invention.

[0061] Figure ID:

[0062] 1- inertial measurement system tooling, 2- outer ball cover, 3- convection fan, 4- inner ball cover, 5- platform support transfer mechanism, 6- platform, 7- inertial instrument assembly, 8- heating plate, 9- first-stage temperature field, 901- inner ball cover air outlet area, 902- inner ball cover air inlet area, 10- second-stage temperature field. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is: a temperature field control method suitable for an inertial measurement system, the inertial measurement system comprising: an inertial measurement system tooling 1, an outer ball cover 2, a convection fan 3, an inner ball cover 4, a table support transfer mechanism 5, a table 6, an inertial instrument assembly 7, a heating plate 8, a heating resistor, a temperature sensor and an external control unit, wherein:

[0064] The inner ball cover 4 is located inside the outer ball cover 2, and the platform 6 is located inside the inner ball cover 4. The outer ball cover 2, the inner ball cover 4, and the platform 6 are all spheres and share a common center.

[0065] One end of the platform support transfer mechanism 5 passes through the outer spherical cover 2 and the inner spherical cover 4 in sequence and is fixed on the platform 6, and the other end is connected to the inertial measurement system tooling 1;

[0066] The inertial instrument assembly 7 is placed inside the platform 6; the heating resistor is attached to the inertial instrument assembly 7 to control the temperature of the inertial instrument assembly 7 in a stable state;

[0067] The inner ball cover 4 is provided with air holes for gas circulation; two convection fans 3 are symmetrically installed at the upper left and upper right of the inner ball cover 4, respectively, for driving the air inside the inner ball cover 4 to flow upward into the interlayer between the outer ball cover 2 and the inner ball cover 4;

[0068] A plurality of heating plates 8 are distributed around the air holes below the inner ball cover 4 to heat the gas flowing from the interlayer into the inner ball cover 4;

[0069] A plurality of temperature sensors are respectively distributed around the two convection fans 3 and the plurality of heating plates 8 for monitoring the real-time temperature;

[0070] The external control unit receives the temperature measured by the temperature sensor in real time, performs temperature field control calculations, and then sends control instructions to the heating plate and the convection fan respectively to adjust the heating duty cycle of the heating plate and the fan speed.

[0071] The areas around the two convection fans 3 are defined as the air outlet area 901, i.e., the area where the air flows out of the inner ball cover 4; the areas around the plurality of heating plates 8 are defined as the air inlet area 902, i.e., the area where the air flows into the inner ball cover 4;

[0072] Based on the requirements of multi-level partition temperature field control, the inertial measurement system is divided into: the first level temperature field 9 and the second level temperature field 10; wherein:

[0073] The first-stage temperature field 9 is the temperature field of the interlayer between the outer ball cover 2 and the inner ball cover 4, which is divided into two areas, the air outlet area 901 and the air inlet area 902, and the temperature is controlled by the convection fan 3 and the heating plate 8;

[0074] The second temperature field 10 is the temperature field inside the platform 6, and the temperature is controlled by a heating resistor.

[0075] The air inside the system starts from the platform 6, flows upward and leaves the inner ball cover 4, flows into the interlayer of the double-layer ball cover, flows from top to bottom in the interlayer, flows into the inner ball cover 4 from the bottom, and finally flows to the platform 6. On the whole, the air inside the inertial measurement system flows in the shape of a magnetic field;

[0076] Through the flow of air inside the inertial measurement system, the heat flux emitted by the platform 6 is sent into the interlayer of the double-layer ball cover through the convection fan 3, and then conducted to the external environment of the inertial measurement system through the outer ball cover 2.

[0077] The temperature field control method comprises the following steps:

[0078] (1) Arrange multiple temperature sensors, heating plates / heating resistors and fans in the inertial measurement system;

[0079] (2) Divide the internal temperature field of the inertial measurement system into the first-level temperature field and the second-level temperature field from the outside to the inside;

[0080] (3) Real-time measurement of the internal temperature field state of the inertial measurement system through the arranged temperature sensors;

[0081] (4) Based on the first-level temperature field state of the inertial measurement system, the heating duty ratio H of the heater in the air outlet area is calculated by the fuzzy control method of the first-level temperature field control. 出 , Heating duty ratio H of the heating plate in the air inlet area 进 and fan speed control instruction F;

[0082] (5) Based on the second-stage temperature field state of the inertial measurement system, the second-stage temperature field is estimated by the extended observer to control the disturbance z of each temperature control point 2j ; The temperature control point is the location of the temperature sensor.

[0083] (6) Based on the state of the second-stage temperature field and the estimated disturbances of each temperature control point, the control instruction u of the heating duty cycle of each heating resistor in the second-stage temperature field is calculated 2j ;

[0084] (7) According to the control instructions of each level of temperature field, adjust the heating duty cycle of the heating plate / heating resistor and the fan speed.

[0085] (8) Repeat (3) to (7) to achieve temperature field control of the inertial measurement system.

[0086] The temperature sensors in step (1) are distributed in the inertial instrument, the surface of the platform and the internal space of the inertial measurement system, and can fully measure the internal temperature field state of the inertial measurement system.

[0087] The fan in step (1) forces the internal air to flow, thereby ensuring that the temperature inside the inertial measurement system is uniform, and causing the air inside the system to flow in a magnetic field shape with the platform as the center.

[0088] The heating plates in step (1) are located in the air outlet area and the air inlet area, and the heating resistors are located next to each inertial instrument.

[0089] The first-level temperature field and the second-level temperature field divided in step (2) correspond to the temperature field between the inner and outer spherical covers of the inertial measurement system and the temperature field of the platform body, respectively.

[0090] The implementation method of step (4) is as follows:

[0091] The air outlet area and the air inlet area divided by the first-stage temperature field, that is, the area where the air flows out of the inner ball cover and the area where the air flows into the inner ball cover, are zoned and controlled.

[0092] Calculate the temperature error of the first-stage temperature control outlet area as e 出 (t i )=T m出 -T d出 ;

[0093] Calculate the temperature change rate of the first-stage temperature control outlet area as

[0094] Calculate the temperature error of the first-stage temperature control air inlet area as e 进 (t i )=T m进 -T d进 ;

[0095] According to the outlet temperature error e 出 (t i ), temperature error of air inlet area e 进 (t i ) and the outlet area error change rate Δe 出 (t i ) value, and divide each parameter into fuzzy intervals, which can be divided into five fuzzy intervals: NB, NM, Z, PM, and PB;

[0096] According to the fuzzy control rule table, the servo control instruction H of the first-level temperature field control heating duty cycle of the heater and fan speed is calculated. 出 , H 进 , F.

[0097] Among them, T d出 and T m出 are the reference temperature of the air outlet area and the average value of the measured temperature at each point in the air outlet area, T d进 and Tm进 are the set reference temperature of the air inlet area and the average value of the measured temperature at each point in the air inlet area, and Δt is the sampling period.

[0098] The implementation method of step (5) is as follows:

[0099] Calculate the temperature error of each temperature measurement point of the second-stage temperature control as e 2j (t i )=T m2j -T d2j

[0100] Estimating the total disturbance of uncertainty and cross-coupling disturbance of heat sources acting on the system, the linear extended observer (LESO) equation is:

[0101]

[0102] Where, j=1,...,n is the number of the multi-channel temperature sensor, T d2j and T m2j These are the reference temperature set for each point on the platform and the actual temperature measured at each point. 1j is the temperature of the temperature sensor estimated by the observer, z 2j is the total disturbance of the temperature sensor estimated by the observer, u 2j is the input of the heating duty cycle of the heating resistor corresponding to number j, and β1 and β2 are the observer gains.

[0103] The implementation method of step (6) is as follows:

[0104] Calculate the servo control instruction u of the heating duty ratio of each heating resistor in the second-stage temperature field 2j :

[0105]

[0106] Among them, k pj , k ij , k dj are the PID controller parameters.

[0107] The implementation method of step (8) is as follows:

[0108] Repeat steps (3) to (7) to continuously adjust the heating duty cycle and fan speed of each heating plate / heating resistor inside the inertial measurement system to achieve temperature field control of the inertial measurement system.

[0109] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0110] Example:

[0111] like Figure 1 As shown, this embodiment is implemented in an inertial measurement system sample, and provides a temperature field control method applicable to an inertial measurement system, the method comprising the following steps:

[0112] (1) Arrange multiple temperature sensors, heating plates / heating resistors and fans in the inertial measurement system;

[0113] (2) Dividing the internal temperature field of the inertial measurement system into a first-level temperature field 9 and a second-level temperature field 10 from the outside to the inside;

[0114] (3) Real-time measurement of the internal temperature field state of the inertial measurement system through the arranged temperature sensors;

[0115] (4) Based on the state of the first-level temperature field 9 of the inertial measurement system, the heating duty ratio H of the heating plate 7 is calculated by the fuzzy control method of the first-level temperature field control. 出 , H 进 and the control instruction F of the speed of fan 3;

[0116] (5) Based on the state of the second-stage temperature field 10 of the inertial measurement system, the second-stage temperature field is estimated by the extended observer to control the disturbance z of each temperature control point 2j .

[0117] (6) Based on the state of the second-stage temperature field 10 and the estimated disturbances of each temperature control point, the control instruction u of the heating duty cycle of the second-stage temperature field heating resistor is calculated. 2j ;

[0118] (7) According to the control instructions of each level of temperature field, adjust the heating duty cycle of the heating plate 7 / heating resistor and the fan speed 3.

[0119] (8) Repeat (3) to (7) to achieve temperature field control of the inertial measurement system.

[0120] The prototype structure of the inertial measurement system in the above embodiment is as follows: Figure 2 The inertial measurement system is composed of an inertial measurement system tooling 1, an outer ball cover 2, a convection fan 3, an inner ball cover 4, a table support transfer mechanism 5, a table 6, an inertial instrument assembly 7, a heating plate 8 and heating resistors distributed inside the table. The multi-level partitioned temperature field control adopted by the inertial measurement system is composed of a first-level temperature field 9 and a second-level temperature field 10. The first-level temperature field 9 is the temperature field control of the interlayer of the double-layer ball cover, which is divided into two areas, the air outlet area 901 and the air inlet area 902, for temperature control, that is, the area where air flows out of the inner ball cover 4 and the area where air flows into the inner ball cover 4. The second-level temperature field 10 is the temperature field control of the table 6.

[0121] The air flow inside the inertial measurement system in the above embodiment is as follows: Figure 3As shown. The convection fan 3 is used to force the internal air to flow inside the inertial measurement system, minimizing the effect of natural convection that is sensitive to acceleration on the temperature field. The convection fans 3 are symmetrically arranged on the inner spherical cover, so that the air inside the system starts from the platform 6, flows upward and leaves the inner spherical cover 4, flows into the interlayer of the double-layer spherical cover, flows from top to bottom in the interlayer, flows into the inner spherical cover 4 from the bottom, and finally flows to the platform 6. On the whole, the air inside the inertial measurement system flows in the shape of a magnetic field.

[0122] In the embodiment, the heat flux emitted by the platform (6) is sent into the interlayer of the double-layer spherical cover through the convection fan 3 by the flow of air inside the inertial measurement system, and then conducted to the external environment of the inertial measurement system by the outer spherical cover 2.

[0123] The temperature sensors arranged in the step (1) are distributed in the inertial instrument 7, the surface of the platform 6 and the internal space of the inertial measurement system, and can fully measure the internal temperature field state of the inertial measurement system; the heating plates 8 are arranged symmetrically on the outside of the inner ball cover 4, and the heating resistors are distributed around each inertial instrument in the platform 6.

[0124] The implementation method of step (4) is as follows:

[0125] Calculate the temperature error of the first-stage temperature control outlet area 901 as e 出 (t i )=T m出 -T d出 ;

[0126] Calculate the temperature error change rate of the first-level temperature control outlet area 901 as

[0127] The temperature error of the first-stage temperature control air inlet area 902 is calculated as e 进 (t i )=T m进 -T d进 ;

[0128] According to the outlet temperature error e 出 (t i ), temperature error of air inlet area e 进 (t i ) and the outlet area error change rate Δe 出 (t i ) is divided into five fuzzy intervals: NB, NM, Z, PM, and PB. A method for dividing the intervals is shown in Table 1.

[0129] Table 1 Schematic diagram of fuzzy interval division

[0130] NB <![CDATA[e 出 (t i )<-3.0℃]]> <![CDATA[Δe 出 (t i )<-0.05℃]]> <![CDATA[e 进 (t i )<-3.0℃]]> NM <![CDATA[-3.0℃<e 出 (t i )<-0.1℃]]> / <![CDATA[-3.0℃<e 进 (t i )<-0.1℃]]> Z <![CDATA[-0.1℃<e 出 (t i )<0.1℃]]> <![CDATA[-0.05℃<Δe 出 (t i )<0.05℃]]> <![CDATA[-0.1℃<e 进 (t i )<0.1℃]]> PM <![CDATA[0.1℃<e 出 (t i )<3℃]]> / <![CDATA[0.1℃<e 进 (t i )<3℃]]> PB <![CDATA[3.0℃<e 出 (t i )]]> <![CDATA[0.05℃<Δe 出 (t i )]]> <![CDATA[3.0℃<e 进 (t i )]]>

[0131] According to the fuzzy control rule table of the air outlet area, the servo control instruction H of the heating duty cycle of the heating plate and the fan speed in the first-stage air outlet area is calculated. 出 , F. The specific adjustment method is shown in Table 2 below.

[0132] Table 2 Fuzzy control rules for air outlet area

[0133]

[0134] According to the fuzzy control rule table of the air inlet area, the servo control instruction H of the heating duty ratio of the heating plate in the first-stage air inlet area is calculated. 进 The specific adjustment method is shown in Table 3 below.

[0135] Table 3 Fuzzy control rules for air inlet area

[0136] <![CDATA[e 进 (t i )]]> Control instructions NB <![CDATA[H 进max ]]> NM <![CDATA[H 进+ ]]> Z <![CDATA[H 进keep ]]> PM <![CDATA[H 进- <!-- 8 -->]]> PB <![CDATA[H 进- ]]>

[0137] Among them, T d出 and T m出 are the reference temperature of the air outlet area and the average value of the measured temperature at each point in the air outlet area, T d进 and T m进 are the set reference temperature of the air inlet area and the average value of the measured temperature at each point in the air inlet area, and Δt is the sampling period.

[0138] H means adjusting the duty cycle of the heating plate, which is between 0-100%. 出max Indicates that the duty cycle of the heater in the air outlet area is 100%, H 出+ Indicates that the duty cycle of the heater in the air outlet area is 1% higher than now. 出- It means that the duty cycle of the heater in the air outlet area is 1% lower than the current one. 出keep Indicates that the duty cycle of the heater in the air outlet area remains at the current value. 进max Indicates that the duty cycle of the heating plate in the air inlet area is 100%, H 进+ Indicates that the duty cycle of the heating plate in the air inlet area is 1% higher than now. 进- Indicates that the duty cycle of the heating plate in the air inlet area is 1% lower than the current one. 进keep Indicates that the duty cycle of the heater in the air inlet area remains at the current value.

[0139] F means adjusting the fan speed. The convection fan speed is divided into 0 to 10 levels. In order to ensure uniform temperature inside the system and minimize the impact of thermal convection, the fan must keep working and maintain at least the minimum speed F. min When the system is working, the fan speed must not be lower than F min . F max Indicates that the fan speed is at the highest level 10, F +Indicates that the fan speed is one level higher than the current speed. - Indicates that the fan speed is one level lower than the current speed.

[0140] The implementation method of step (5) is as follows:

[0141] Calculate the temperature error of each temperature measurement point of the second-stage temperature control 10 as e 2j (t i )=T m2j -T d2j ;

[0142] Estimating the total disturbance of uncertainty and cross-coupling disturbance of heat sources acting on the system, the linear extended observer (LESO) equation is:

[0143]

[0144] Wherein, j=1,...,6 are the numbers of the multi-channel temperature sensors, corresponding to three gyroscopes and three accelerometers, respectively. d2j and T m2j These are the reference temperature set for each point on the platform and the actual temperature measured at each point. 1j is the temperature of the temperature sensor estimated by the observer, z 2j is the total disturbance of the temperature sensor estimated by the observer, u 2j is the input of the heating duty cycle of the heating resistor corresponding to number j, and β1 and β2 are the observer gains.

[0145] The implementation method of step (6) is as follows:

[0146] Calculate the servo control instruction u of the heating duty ratio of each heating resistor in the second-stage temperature field 2j :

[0147]

[0148] Among them, k pj , k ij , k dj are the PID controller parameters.

[0149] The implementation method of step (8) is as follows:

[0150] Repeat steps (3) to (7) to continuously adjust the heating duty cycle and fan speed of each heating plate / heating resistor inside the inertial measurement system to achieve temperature field control of the inertial measurement system.

[0151] The measurement results of each temperature measurement point inside the inertial measurement system of this embodiment are as follows: Figure 4As shown, this method can effectively control the temperature field inside the inertial measurement system. The temperature of each temperature measurement point inside the system is stable, which can effectively suppress the influence of external environmental temperature fluctuations and reduce the influence of internal complex coupled heat sources. The present invention can establish a stable and uniform temperature field inside the inertial measurement system, and has good practical effects.

[0152] The technical effects of the embodiments of the present invention are as follows: (1) The first-level temperature field control 9 of the inertial measurement system ensures the heat dissipation of the heating element and the stability of the air temperature flowing to the platform, and establishes a stable temperature field around the platform 6. (2) The second-level temperature field control 10 of the inertial measurement system establishes multiple temperature control points on the platform 6, and at the same time observes and compensates for the influence of disturbances through an expanded observer, so that the temperature field of the platform is uniform and stable. (3) The inertial measurement system adopts a multi-level regional temperature field control strategy, combined with fuzzy control and expanded observers to improve the robustness of the system, effectively reducing the influence of complex coupling of internal heat sources and ambient temperature fluctuations on the temperature field in the system, and improving the temperature adaptability of the inertial measurement system.

[0153] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims

1. An inertial measurement system, characterized in that include: An inertial measurement system tooling (1), an outer spherical cover (2), a convection fan (3), an inner spherical cover (4), a platform support transfer mechanism (5), a platform (6), an inertial instrument assembly (7), a heating plate (8), a heating resistor, a temperature sensor, and an external control unit, wherein: The inner ball cover (4) is located inside the outer ball cover (2), the platform (6) is located inside the inner ball cover (4), and the outer ball cover (2), the inner ball cover (4) and the platform (6) are all spheres and share a common center. One end of the platform support transfer mechanism (5) passes through the outer spherical cover (2) and the inner spherical cover (4) in sequence and is fixed on the platform (6), and the other end is connected to the inertial measurement system tooling (1); The inertial instrument component (7) is placed inside the platform (6); a heating resistor is attached to the inertial instrument component (7) to control the temperature of the inertial instrument component (7) in a stable state; The inner ball cover (4) is provided with air holes for gas circulation; two convection fans (3) are symmetrically mounted on the upper left and upper right of the inner ball cover (4) respectively, for driving the air inside the inner ball cover (4) to flow upward into the interlayer between the outer ball cover (2) and the inner ball cover (4); A plurality of heating plates (8) are distributed around the air holes below the inner spherical cover (4) to heat the gas flowing from the interlayer into the inner spherical cover (4); A plurality of temperature sensors are respectively distributed around the two convection fans (3) and a plurality of heating plates (8) for monitoring real-time temperature; The external control unit receives the temperature measured by the temperature sensor in real time, performs temperature field control calculations, and then sends control instructions to the heating plate and the convection fan respectively to adjust the heating duty cycle of the heating plate and the fan speed.

2. An inertial measurement system according to claim 1, characterized in that: The area around the two convection fans (3) is defined as an air outlet area (901), that is, the area where air flows out of the inner spherical cover (4); the area around the plurality of heating plates (8) is defined as an air inlet area (902), that is, the area where air flows into the inner spherical cover (4); Based on the requirements of multi-level partition temperature field control, the inertial measurement system is divided into: a first-level temperature field (9) and a second-level temperature field (10); wherein: The first-stage temperature field (9) is the temperature field of the interlayer between the outer spherical cover (2) and the inner spherical cover (4), which is divided into two areas, namely, the air outlet area (901) and the air inlet area (902), and the temperature is controlled by the convection fan (3) and the heating plate (8); The second-level temperature field (10) is the temperature field inside the platform (6), and the temperature is controlled by a heating resistor.

3. An inertial measurement system according to claim 1, characterized in that: The air inside the system starts from the platform (6) and flows upward, leaving the inner spherical cover (4), and flows into the interlayer of the double-layer spherical cover. In the interlayer, the air flows from top to bottom, flows into the inner spherical cover (4) from the bottom, and finally flows to the platform (6). Overall, the air inside the inertial measurement system flows in the shape of a magnetic field. Through the flow of air inside the inertial measurement system, the heat flux emitted by the platform (6) is sent into the interlayer of the double-layer ball cover through the convection fan (3), and then conducted to the external environment of the inertial measurement system through the outer ball cover (2).

4. A temperature field control method suitable for an inertial measurement system, characterized in that include: S1. Real-time measurement of the internal temperature field state of the inertial measurement system through the arranged temperature sensors; S2. Based on the first-level temperature field state of the inertial measurement system, the heating duty cycle control instruction H of the heating plate in the first-level temperature field (9) of the air outlet area is obtained by the fuzzy control method. 出 , heating duty ratio control command H of the heating plate in the air inlet area 进 and fan speed control instruction F; S3, based on the state of the second-stage temperature field (10) of the inertial measurement system, the disturbance z of each temperature control point in the second-stage temperature field is estimated by the extended observer 2j ; The temperature control point is the location of the temperature sensor; S4, based on the state of the second-stage temperature field and the estimated disturbances of each temperature control point, calculate the control instruction u of the heating duty cycle of each heating resistor in the second-stage temperature field 2j ; S5. According to the control instructions of each level of temperature field, the heating duty ratio of the heating plate and the heating resistor and the fan speed are adjusted; S6. Return to step S1 and repeat the iteration to realize the temperature field control of the inertial measurement system.

5. The temperature field control method applicable to an inertial measurement system according to claim 4, characterized in that: In S2, the fuzzy control method is used to calculate the first-level temperature field to control the heating duty ratio H of the heating plate in the air outlet area. 出 , Heating duty ratio H of the heating plate in the air inlet area 进 The method of controlling the fan speed command F is: Calculate the outlet temperature error e of the outlet area (901) of the first-level temperature field 出 (t i ) and outlet temperature error change rate Δe 出 (t i ); Calculate the air inlet temperature error e of the air inlet area (902) of the first-stage temperature field 进 (t i ); According to the outlet temperature error e 出 (t i ), temperature error of air inlet area e 进 (t i ) and the outlet temperature error change rate Δe 出 (t i ) value, and divide the fuzzy interval for each parameter; Formulate a fuzzy control rule table based on the fuzzy interval; By locating the outlet temperature error e of the outlet area (901) 出 (t i ) and the outlet temperature error change rate Δe 出 (t i ) in the fuzzy interval, and look up the table to obtain the heating duty ratio H of the heating plate in the outlet area in the current state. 出 and fan speed F; The temperature error e of the air inlet area (902) is located 进 (t i ) in the fuzzy interval, look up the table to obtain the heating duty ratio H of the heating plate in the air inlet area 进 .

6. The temperature field control method applicable to an inertial measurement system according to claim 5, characterized in that: Air outlet temperature error 出 (t i ), air inlet temperature error e 进 (t i ) and the outlet temperature error change rate Δe 出 (t i ) are: e 出 (t i )=T m出 -T d出 ; e 进 (t i )=T m进 -T d进 ; Among them, T d出 is the reference temperature of the air outlet area, T m出 is the average value of the measured temperature at each point in the outlet area, T d进 is the reference temperature of the air inlet area, T m进 is the average value of the measured temperature at each point in the air inlet area, and Δt is the sampling period.

7. The temperature field control method applicable to an inertial measurement system according to claim 5, characterized in that: The fuzzy control rule table includes the fuzzy control rule table of the air outlet area and the fuzzy control rule table of the air inlet area, where: When formulating the fuzzy control rule table for the air outlet area, the air outlet temperature error e is also considered. 出 (t i ) and the outlet temperature error change rate Δe 出 (t i ): When Δe 出 (t i ) remains unchanged, and e 出 (t i ) changes from negative to positive, the duty cycle of the heater and the fan speed gradually decrease; when e 出 (t i ) remains unchanged, and Δe 出 (t i ) changes from a negative value to a positive value, the duty cycle of the heater remains unchanged, while the fan speed gradually increases according to the situation; for the heater duty cycle and fan speed of the outlet area in each fuzzy interval, the corresponding heating duty cycle control instruction H of the heater in the inlet area is formulated. 出 and fan speed control instruction F; When formulating the fuzzy control rule table for the air inlet area, the temperature error e of the air inlet area is considered. 进 (t i ): when e 进 (t i ) changes from negative to positive, the heating duty ratio H of the heating plate in the air inlet area 进 Gradually reduce; for each fuzzy interval of the air inlet area heating plate duty cycle, formulate the corresponding air inlet area heating plate heating duty cycle control instruction H 进 .

8. The temperature field control method applicable to an inertial measurement system according to claim 7, characterized in that: When adjusting the fan speed, in order to ensure uniform temperature inside the system and minimize the impact of heat convection, the fan must keep working and maintain at least the minimum speed F min .

9. The temperature field control method applicable to an inertial measurement system according to claim 4, characterized in that: The disturbance z of each temperature control point in the second-stage temperature field is estimated by the extended observer 2j , specifically: Calculate the temperature error of each temperature measurement point of the second-stage temperature control as e 2j (t i )=T m2j -T d2j ; Estimating the total disturbance of uncertainty and cross-coupling interference of heat sources acting on the system, the linear extended observer equation is: Where, j=1,...,n is the number of the multi-channel temperature sensor, T d2j and T m2j The reference temperature and the measured temperature of each point are set respectively for each point of the platform; 1j is the temperature of the temperature sensor estimated by the observer, z 2j is the total disturbance of the temperature sensor estimated by the observer, u 2j is the input of the heating duty cycle of the heating resistor corresponding to number j, and β1 and β2 are the observer gains.

10. The temperature field control method applicable to an inertial measurement system according to claim 9, characterized in that: The control instruction u of the heating duty ratio of each heating resistor in the second-level temperature field 2j for: Among them, k pj , k ij , k dj are the PID controller parameters.

Images