Constant temperature control device and method for inertial navigator

Abstract

The invention provides a constant temperature control device and method of an inertial navigator, and relates to the technical field of inertial navigators, the device comprises an MEMS inertial sensor, a heat conduction block, a controller, a temperature sensor, a refrigeration sheet, a radiator and a power supply; the heat conduction block is provided with at least three pairwise orthogonal mounting surfaces; the MEMS inertial sensor is mounted on mounting surfaces which are orthogonal in pairs, a first side surface of the refrigeration sheet is mounted on one of the mounting surfaces through a heat-conducting medium, and a radiator is mounted on a second side surface of the refrigeration sheet through the heat-conducting medium; the temperature sensor is mounted on the heat conduction block; the controller is electrically connected with the temperature sensor and the power supply, and the power supply is electrically connected with the refrigeration sheet; the temperature sensor collects the temperature of the heat conduction block; the controller outputs a control signal based on a constant temperature control algorithm and the temperature data; and the power supply controls the refrigeration sheet to heat or refrigerate by using a control signal. The heat dissipation efficiency of the MEMS inertial sensor is improved, the temperature drift is reduced, and the precision and stability of long-term measurement are improved.

Description

Technical Field

[0001] The present application relates to the technical field of inertial navigation instruments, and in particular to a constant temperature control device and method for an inertial navigation instrument. Background Art

[0002] High-precision inertial navigation systems are important components for achieving positioning and navigation functions in aerospace, automotive, and robotics fields. High-precision positioning and navigation functions mainly rely on high-precision MEMS (Micro-Electro-Mechanical System) inertial sensors. High-precision MEMS inertial sensors mainly include high-precision gyroscopes and high-precision accelerometers. Gyroscopes can be used to measure the three-axis angular velocity signals of objects moving relative to the navigation coordinate system, and accelerometers can be used to measure the three-axis acceleration signals of objects moving in the navigation coordinate system.

[0003] High-precision inertial navigation systems usually use single-axis MEMS inertial sensors or multi-axis MEMS inertial sensors to measure the angular velocity and acceleration data of the object in three-dimensional space, and then use inertial navigation algorithms to calculate the object's posture and motion data. High-precision inertial navigation systems generally require the combination of three high-precision gyroscopes and three high-precision accelerometers to achieve high-precision inertial navigation functions. Summary of the invention

[0004] The present application provides a constant temperature control device and method for an inertial navigation system, so that a MEMS inertial sensor is in a smaller temperature variation range during long-term operation, thereby reducing the temperature drift of the MEMS inertial sensor and improving the accuracy and stability of long-term measurement.

[0005] In a first aspect, the present application provides a constant temperature control device for an inertial navigation system, the constant temperature control device comprising: MEMS inertial sensor, heat conduction block, controller, temperature sensor, cooling sheet, heat sink and power supply; the heat conduction block has multiple mounting surfaces, at least three of the multiple mounting surfaces are orthogonal to each other; The MEMS inertial sensor is mounted on three mounting surfaces orthogonal to each other through a heat-conducting medium, the first side surface of the cooling plate is mounted on one of the mounting surfaces through a heat-conducting medium, the second side surface of the cooling plate is mounted with the radiator through a heat-conducting medium, and the temperature sensor is mounted on the heat-conducting block, wherein the first side surface and the second side surface are two opposite side surfaces of the cooling plate; The controller is electrically connected to the temperature sensor and the power supply respectively, and the power supply is electrically connected to the refrigeration plate; The temperature sensor is used to collect the temperature of the heat conducting block and transmit the collected temperature data to the controller; The controller is used to receive the temperature data, output a control signal based on a PID constant temperature control algorithm, and transmit the control signal to the power supply; The power supply is used to receive the control signal and use the control signal to control the refrigeration plate to perform a heating operation or a cooling operation.

[0006] Compared with the prior art, the embodiment of the present application has made two improvements to the measurement performance of the inertial navigation system. First, the heat dissipation efficiency of the MEMS inertial sensor is improved while the temperature difference between the sensors is reduced. That is, the prior art uses the circuit board welded on the bottom of the MEMS inertial sensor as the main heat dissipation path, and is changed to directly conduct the heat to the heat conductive block through the top of the MEMS inertial sensor as the main heat dissipation path. Since the heat conductivity of the heat conductive block is much higher than that of the circuit board, the heat dissipation efficiency of the MEMS inertial sensor is greatly improved. In addition, the MEMS inertial sensors are installed on the same heat conductive block, so that the temperature difference of each MEMS inertial sensor is reduced. Second, an active temperature control system is composed of a controller, a temperature sensor, a power supply, a heat conductive block, a cooling plate and a radiator to control the temperature of the heat conductive block to be in a constant temperature state, so that the MEMS inertial sensor is in a smaller temperature variation range during long-term operation. Through the above two improvements, the embodiment of the present application reduces the temperature drift of the MEMS inertial sensor and improves the accuracy and stability of long-term measurement.

[0007] In a possible design, the heat conductive block is made of metal or a polymer material with heat conductive properties.

[0008] In a possible design, the top of each MEMS inertial sensor is mounted on the mounting surface via a heat-conducting medium, and a circuit board of the MEMS inertial sensor is mounted on the bottom of each MEMS inertial sensor.

[0009] In a possible design, a heat dissipation structure is provided on the radiator, and the heat dissipation structure includes at least one of a heat dissipation fin, a heat dissipation hole and a heat dissipation tooth.

[0010] In one possible design, the controller includes a program that can execute the PID constant temperature control algorithm and a temperature detection program, wherein the program that can execute the PID constant temperature control algorithm and the temperature detection program are stored in the controller or transmitted to the controller through a communication channel outside the controller.

[0011] In a possible design, the heat sink is a shell, and the heat dissipation structure is provided on the surface of the shell.

[0012] In one possible design, the control signal controls the power supply to output a forward current and a reverse current, wherein the forward current and the reverse current flow in opposite directions.

[0013] In a possible design, the temperature sensor is mounted on one of the mounting surfaces of the heat conducting block or inside the heat conducting block. In a second aspect, the present application provides a constant temperature control method for an inertial navigation system, the method comprising: Collect temperature data of the heat conducting block; Output a control signal according to the temperature data and based on a PID constant temperature control algorithm; The control signal is used to control the refrigeration plate to perform a heating operation or a cooling operation.

[0014] In a possible design, outputting a control signal according to the temperature data and based on a PID constant temperature control algorithm includes: According to the temperature data and based on the PID constant temperature control algorithm, determine whether a heating operation or a cooling operation is required; If so, output a control signal corresponding to a heating operation or a cooling operation; If not, return to the execution step: collect temperature data of the heat conducting block.

[0015] The beneficial effects provided in the above-mentioned second aspect and various possible designs of the above-mentioned second aspect can refer to the beneficial effects brought about by the above-mentioned first aspect and various possible implementation methods of the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The structure diagram of the inertial navigation system in the prior art; Figure 2 A schematic structural diagram of a constant temperature control device for an inertial navigation system provided in an embodiment of the present application; Figure 3 An installation structure diagram of an inertial navigation system without a housing provided in an embodiment of the present application; Figure 4 An installation structure diagram of an inertial navigation system with a housing provided in an embodiment of the present application; Figure 5 A flow chart of a constant temperature control method for an inertial navigation system provided in an embodiment of the present application; Figure 6 A flow chart of another constant temperature control method for an inertial navigation system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] In this application, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c alone can mean: a alone, b alone, c alone, a and b in combination, a and c in combination, b and c in combination, or a, b, and c in combination, where a, b, and c can be single or multiple. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0018] The directions or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "up", "down", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0019] The terms "connected" and "connected" should be understood in a broad sense. For example, the "connected" or "connected" of a circuit structure can refer to not only physical connection, but also electrical connection or signal connection. For example, it can be directly connected, that is, physically connected, or indirectly connected through at least one intermediate element, as long as the circuit is connected, or it can be the internal connection of two elements; signal connection can refer to signal connection through a circuit or through a media medium, such as radio waves. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0020] In the prior art, the bottom of the MEMS inertial sensor in the inertial navigation system is usually welded on a circuit board, and each circuit board is installed on the bracket of the inertial navigation system in three axes, X, Y, and Z. Each circuit board is installed in a decentralized manner and is independent of each other. The entire bracket is installed on the bottom plate of the inertial navigation system.

[0021] Through the installation method in the above-mentioned prior art, part of the heat generated by each MEMS inertial sensor during operation is conducted to the circuit board through the bottom of the MEMS inertial sensor, and then conducted to the installation surface through the circuit board; the other part of the heat is dissipated through air convection on the top surface of the MEMS inertial sensor. Among them, on the path of heat dissipation through the circuit board, the entire heat conduction path is long and the thermal conductivity is low, which is not conducive to the heat dissipation of the MEMS inertial sensor and the heat dissipation effect is poor. For example, the overall thermal conductivity of the circuit board is about 0.2W~10W / m·K, and the thermal conductivity is low, especially when the copper thickness of the circuit board is thin or there are fewer vias, the thermal conductivity will be lower. On the other hand, the MEMS inertial sensor is small in size, generally not exceeding 15mm*15mm, and the surface heat dissipation area is very small, while the air convection heat dissipation generally does not exceed 10W / m·K, and the influence of air convection on the heat dissipation effect is also very small, resulting in poor heat dissipation effect. As the chip integration increases, the heat generated by the chip will also become greater. Generally speaking, the operating temperature of electronic components is -40℃~85℃. For every 1℃ increase in temperature, its reliability will decrease by 5%. The performance of the inertial navigation module is mainly reflected in parameters such as measurement accuracy and long-term cumulative error. Although the performance temperature coefficient of each sensor may vary, if the temperature of the sensor rises, the cumulative error will also increase, its accuracy will deteriorate accordingly, and the cumulative error will also increase. Therefore, the heat dissipation effect will have a great impact on the accuracy of the inertial navigation module.

[0022] In the prior art, in one example, the structure diagram of the inertial navigation system is shown in Figure 1 , each device is described below. Figure 1 As shown: Device 1: MEMS inertial sensor, including a MEMS gyroscope and a MEMS accelerometer, the inertial sensor in the Z-axis direction is installed parallel to the bottom plate.

[0023] Device 2: A MEMS inertial sensor circuit board, used for supporting the MEMS inertial sensor, the MEMS inertial sensor being soldered on the MEMS inertial sensor circuit board.

[0024] Device 3: Bracket for inertial navigation unit.

[0025] Device 4: Base plate of the inertial navigation unit.

[0026] Device 5: MEMS inertial sensor, including a MEMS gyroscope and a MEMS accelerometer, wherein the Y-axis inertial sensor is installed perpendicular to the base plate and perpendicular to the Y-axis direction.

[0027] Device 6: A MEMS inertial sensor circuit board, used for supporting the MEMS inertial sensor, the MEMS inertial sensor being welded on the MEMS inertial sensor circuit board.

[0028] Device 7: A MEMS inertial sensor, including a MEMS gyroscope and a MEMS accelerometer, wherein the X-axis inertial sensor is installed perpendicular to the base plate and perpendicular to the X-axis direction.

[0029] Device 8: A MEMS inertial sensor circuit board, used for supporting the MEMS inertial sensor, the MEMS inertial sensor being welded on the MEMS inertial sensor circuit board.

[0030] The installation and layout methods of MEMS inertial sensors in the prior art make the heat generated during the operation of the MEMS inertial sensors mainly rely on the heat conduction of the circuit board and the air convection heat dissipation on the top of the MEMS inertial sensor. Both heat dissipation methods are passive heat dissipation with low thermal conductivity and poor heat dissipation effect. Therefore, the temperature of the MEMS inertial sensor is greatly drifted under the influence of two factors: changes in the external environment and the accumulation of heat during operation. In addition, the temperature deviation between the MEMS inertial sensors is large due to uneven heat dissipation, which has an adverse effect on the measurement accuracy of the inertial navigation system and the accumulated error of long-term operation.

[0031] Inertial navigation systems generally require high-precision MEMS gyroscopes for the three axes XYZ and high-precision MEMS accelerometers for the three axes XYZ. If it is a combined inertial navigation system, GNSS, magnetometers, barometers and other sensors are also required for auxiliary measurements. For example, in general, the power consumption of high-precision MEMS sensors is 0.2W~0.3W. For a set of high-precision inertial navigation systems, multiple MEMS inertial sensors are required (six for single-axis MEMS inertial sensors and four for dual-axis MEMS inertial sensors), with a total power consumption of 1.2W~1.8W. For an inertial navigation system with high integration and relatively small size, the power consumption is relatively high.

[0032] The layout of MEMS inertial sensors in the existing technology, on the one hand, because the heat generated during the operation of the MEMS inertial sensor is dissipated by circuit board conduction and air convection, the thermal conductivity is very small, the thermal resistance is high, and the heat dissipation is poor, resulting in high heat accumulation of the MEMS inertial sensor itself, which is usually 5℃~10℃ higher than the ambient air temperature; on the other hand, because high-precision inertial navigation navigators are used in the aerospace or automotive fields, the temperature variation range of the long-term working environment is huge, and the extreme variation range can reach 110℃~140℃, and the temperature drift of the MEMS inertial sensor will increase with the increase of the temperature of the external environment, which makes the long-term measurement accuracy of the inertial navigation system significantly deteriorated. Due to the inconsistency of the heat dissipation thermal resistance of each MEMS inertial sensor, the temperature difference caused by the heat accumulation of each sensor is relatively large, making it difficult for the factory calibration algorithm of the inertial navigation system to handle the consistency of errors.

[0033] It can be seen that the layout of MEMS inertial sensors in the prior art makes it extremely difficult to perform factory calibration of high-precision inertial navigation systems and maintain stable high-precision measurement performance for a long time.

[0034] In order to solve the above problems in the prior art, see Figure 2 , the present application provides a constant temperature control device for an inertial navigation system, such as Figure 2 As shown, the device includes: a MEMS inertial sensor, a heat conductive block, a controller, a temperature sensor, a cooling plate, a heat sink and a power supply; the heat conductive block has a plurality of mounting surfaces, and at least three of the plurality of mounting surfaces are orthogonal to each other.

[0035] The MEMS inertial sensor is installed on three mounting surfaces that are orthogonal to each other through a heat-conducting medium, the first side surface of the cooling plate is installed on one of the mounting surfaces through a heat-conducting medium, the second side surface of the cooling plate is installed with a heat sink through a heat-conducting medium, and the temperature sensor is installed on the heat-conducting block, wherein the first side surface and the second side surface are two opposite sides of the cooling plate.

[0036] The controller is electrically connected to the temperature sensor and the power supply respectively, and the power supply is electrically connected to the refrigeration plate.

[0037] The temperature sensor is used to collect the temperature of the heat conducting block and transmit the collected temperature data to the controller.

[0038] The controller is used to receive temperature data, output a control signal based on a PID constant temperature control algorithm, and transmit the control signal to a power supply.

[0039] The power supply is used to receive the control signal and use the control signal to control the refrigeration plate to perform heating operation or cooling operation.

[0040] The heat conductive block needs to have multiple mounting surfaces, at least three of which are orthogonal to each other (i.e., perpendicular to each other) for mounting MEMS inertial sensors. Since each MEMS inertial sensor includes a MEMS gyroscope and a MEMS accelerometer, the three orthogonal mounting surfaces form the mounting reference surfaces of the MEMS gyroscope and the MEMS accelerometer, i.e., the reference surfaces of the X, Y, and Z axes of the inertial sensor. At the same time, the mounting reference surfaces also serve as the heat dissipation and heating surfaces of the MEMS inertial sensor.

[0041] The specific installation method of the MEMS inertial sensor and the heat conductive block is: the top of the MEMS inertial sensor is attached to the heat conductive block by using a heat conductive medium by flipping the top of the MEMS inertial sensor. High-precision inertial navigation systems require MEMS inertial sensors to measure the three axes of X, Y, and Z. The MEMS inertial sensors (MEMS gyroscopes and MEMS accelerometers) of each axis need to be attached and installed on the corresponding orthogonal surfaces (i.e., surfaces that are perpendicular to each other), ensuring that each MEMS inertial sensor is orthogonal to each other in the three axes of X, Y, and Z, reducing the difficulty of factory calibration of the inertial sensor. In one example, the heat conductive medium can be thermal conductive glue.

[0042] The heat conductive block in this application, on the one hand, needs at least three mounting surfaces that are orthogonal to each other, for mounting high-precision MEMS inertial sensors to ensure that the three axes of the MEMS inertial sensors are orthogonal; on the other hand, it also needs to have a mounting surface for mounting cooling plates and heat sinks. The heat conductive block is a heat conductor for heat exchange between each MEMS sensor and the cooling plate. Its size varies with the size of the MEMS inertial sensor. The side length is usually 20mm~30mm. Each sensor mounting surface needs to be installed with a corresponding axial MEMS gyroscope and MEMS accelerometer. The heating surface of the heat conductive block needs to ensure that it can be fully installed and fit the heat conductive surface of the cooling plate.

[0043] The cooling plate is also called a semiconductor cooling plate or a thermoelectric cooling plate. Its working principle is mainly based on the Peltier effect of semiconductor materials. When a DC current passes through a galvanic couple composed of two different semiconductor materials (such as N-type and P-type semiconductors), heat will be absorbed and released at both ends of the galvanic couple, thereby achieving a cooling or heating effect. Specifically, by providing a forward DC current to the cooling plate, the cooling surface of the cooling plate achieves cooling, and the other side achieves heating; when a reverse DC current is provided to the cooling plate, the cooling surface of the cooling plate will be converted to a heating surface, and the previous heating surface will be converted to a cooling surface. Therefore, by controlling the current direction of the power supply current of the cooling plate, the cooling plate can achieve both cooling and heating effects.

[0044] In the present application, a power supply supplies direct current to the cooling plate, controls the cooling plate to heat or cool the heat conductive block, and achieves the effect of cooling or heating the heat conductive block. In one example, the total power consumption of the MEMS inertial sensor of the inertial navigation system is about 2W. When the cooling plate is used to heat or cool the heat conductive block, considering the dissipated power consumption and the conversion efficiency of the cooling plate, the cooling plate can use a device that is more than 2.5 times the total power consumption of the system, such as a 5W~10W device.

[0045] The installation method of the cooling plate and the heat conducting block is specifically as follows: the first side of the cooling plate is installed on the installation surface of the heat conducting block through a heat conducting medium, and the heat sink is installed on the second side of the cooling plate through a heat conducting medium. The first side and the second side are two opposite sides of the cooling plate. In one example, the heat conducting medium can be heat conducting glue.

[0046] The temperature sensor is used to measure the temperature of the heat conductive block and can be installed on the heat conductive block.

[0047] The power supply is a DC power output device. Under the control of the controller, it can switch the positive and negative directions of the output current according to the control signal output by the controller, providing the refrigeration plate with a forward current for cooling and a reverse current for heating.

[0048] An active temperature control system is formed by a controller, a temperature sensor, a power supply, a heat-conducting block, a cooling plate and a radiator to control the temperature of the heat-conducting block. Specifically, the temperature of the heat-conducting block is collected by a temperature sensor, and the collected temperature data is transmitted to the controller. The controller includes a PID constant temperature control algorithm, and a control signal is output through the PID constant temperature control algorithm. The control signal is used to control the power supply of the cooling plate through the power supply, and then the cooling plate is controlled to perform heating or cooling operations, so as to achieve the effect of controlling the heat-conducting block. The PID constant temperature control algorithm is an existing control method, and its specific implementation method will not be repeated here.

[0049] Compared with the prior art, the embodiment of the present application has made three improvements. First, the heat dissipation efficiency of the MEMS inertial sensor is improved, that is, the prior art uses the circuit board welded on the bottom of the MEMS inertial sensor as the main heat dissipation path to use the top of the MEMS inertial sensor to the heat conductive block as the main heat dissipation path. Due to the high thermal conductivity of the heat conductive block, the heat dissipation effect is better. Second, the temperature difference of the MEMS inertial sensor during long-term operation is reduced, that is, the MEMS inertial sensors are all installed on the orthogonal surface of the heat conductive block through a heat conductive medium. Due to the high thermal conductivity of the heat conductive block, the main heat conductive path of the MEMS inertial sensor is the heat conductive block, so that the temperature of each MEMS inertial sensor is consistent with the heat conductive block to the greatest extent, so that the operating temperature of each MEMS inertial sensor is consistent. Third, an active temperature control system is composed of a controller, a temperature sensor, a power supply, a heat conductive block, a cooling plate and a radiator to control the temperature of the heat conductive block. Through the above three improvements, the MEMS inertial sensor is in a smaller temperature variation range during long-term operation, and the temperature difference between sensors is reduced, which further reduces the temperature drift of the MEMS inertial sensor and improves the long-term measurement accuracy and stability of the inertial navigation system.

[0050] In a possible embodiment, the material of the heat conducting block is a metal material or a polymer material with thermal conductivity, wherein the metal material may be aluminum, aluminum alloy or copper. The thermal conductivity of aluminum, aluminum alloy or copper can reach 200W~400W / m·K, which can greatly improve the thermal conductivity of the heat dissipation path of the MEMS inertial sensor, and is 20~200 times higher than the thermal conductivity through the circuit board and air convection in the prior art, thereby greatly improving the thermal conductivity efficiency of the MEMS inertial sensor. The polymer material with thermal conductivity can also achieve a good thermal conductivity effect, thereby greatly improving the thermal conductivity efficiency of the MEMS inertial sensor.

[0051] In a possible embodiment, the top of each MEMS inertial sensor is mounted on a mounting surface via a heat-conducting medium, and a circuit board of the MEMS inertial sensor is mounted on the bottom of each MEMS inertial sensor. For example, the top of the MEMS inertial sensor is mounted on a heat-conducting block via heat-conducting glue, and the MEMS inertial sensors of the three axes X, Y, and Z are respectively mounted on mounting surfaces that are orthogonal to each other, and the circuit board of the MEMS inertial sensor is welded to the bottom of the MEMS inertial sensor. Since the thermal conductivity of the heat-conducting block is much higher than that of the circuit board, through this structure, the heat-conducting block serves as the main heat conduction path of the MEMS inertial sensor.

[0052] In a possible embodiment, a heat dissipation structure is disposed on the surface of the heat sink, and the heat dissipation structure includes at least one of a heat dissipation fin, a heat dissipation hole, and a heat dissipation tooth.

[0053] In a possible embodiment, the heat dissipation structure is to set vertically distributed heat dissipation teeth on the heat dissipation surface. For example, the cooling plate is attached to the heating surface of the heat conductive block by thermal conductive glue, and the radiator is attached to the other side of the cooling plate by thermal conductive glue. In order to ensure a good heat dissipation effect, the surface of the radiator is provided with vertically distributed heat dissipation teeth, which can make air flow through the heat dissipation teeth from bottom to top, forming better air convection heat exchange and improving the heat dissipation effect of the radiator.

[0054] See also Figure 3 , the embodiment of the present application provides an installation structure diagram without a housing, and the following describes each device, such as Figure 3 As shown: Device 23: A MEMS inertial sensor circuit board, used for fixing and supporting the MEMS inertial sensor, the MEMS inertial sensor being welded on the MEMS inertial sensor circuit board.

[0055] Device 24: MEMS inertial sensor circuit board, used for fixing and supporting the MEMS inertial sensor, the MEMS inertial sensor is welded on the MEMS inertial sensor circuit board.

[0056] Device 25: MEMS inertial sensor, including a MEMS gyroscope and a MEMS accelerometer, mounted on the vertical surface of the heat conductive block.

[0057] Device 26: A heat conductive block, which is used to provide a heat exchange medium with high thermal conductivity for each MEMS inertial sensor, realize the heat dissipation of the MEMS inertial sensor and rapid heat exchange during the heating process, and is also a mounting reference structure for each MEMS inertial sensor and cooling sheet.

[0058] Device 27: A radiator, installed on the cooling fin, for providing heat dissipation to the hot surface of the cooling fin.

[0059] Device 28: A cooling sheet installed on the heat conducting block for cooling or heating the heat conducting block. A heat sink is installed on the other side.

[0060] Device 29: A MEMS inertial sensor circuit board, used for fixing and supporting the MEMS inertial sensor, the MEMS inertial sensor being welded on the MEMS inertial sensor circuit board.

[0061] Device 30: A MEMS inertial sensor circuit board, used for fixing and supporting the MEMS inertial sensor, the MEMS inertial sensor being welded on the MEMS inertial sensor circuit board.

[0062] Device 31: MEMS inertial sensor, including MEMS gyroscope and MEMS accelerometer, mounted on the horizontal surface of the heat conductive block.

[0063] Device 32: Flexible connection material. The flexible connection material is a material for electrically connecting various circuit board components. In one example, the flexible connection material may be a FPC (Flexible Printed Circuit).

[0064] In the embodiment of the present application, the heat dissipation effect can be improved by providing vertically distributed heat dissipation teeth on the surface of the heat sink.

[0065] In a possible embodiment, the radiator can be a shell, and a heat dissipation structure is provided on the surface of the shell. Specifically, the heat dissipation structure is vertically distributed heat dissipation teeth. In practical applications, for an inertial navigation system with a metal shell, the metal shell can be used as a radiator of a cooling plate, and the heat dissipation effect is better. It is necessary to provide a heat dissipation structure on the outer surface of the metal shell, and the heat dissipation structure can be vertically distributed heat dissipation teeth provided on the surface of the shell. During installation, one side of the cooling plate is installed and pasted on a mounting surface of the heat conductive block with a heat conductive medium, and the other side is pasted on the inner wall of the metal shell of the inertial navigation system with a heat conductive medium. The heat generated by the hot surface of the cooling plate during the cooling process is dissipated through the metal shell. In this way, on the one hand, the heat dissipation efficiency is improved, and on the other hand, no additional structural parts are added to save costs.

[0066] See also Figure 4 , the embodiment of the present application provides an installation structure diagram with a metal housing, and the following describes each device, such as Figure 4 As shown: Device 33: The metal casing of the inertial navigation unit with a heat dissipation structure.

[0067] Device 34: A cooling sheet, installed on the heat conducting block, for cooling or heating the heat conducting block. A radiator is installed on the other side.

[0068] Device 35: A heat conductive block, which is used to provide a heat exchange medium with high thermal conductivity efficiency to each MEMS inertial sensor, realize the heat dissipation of the MEMS inertial sensor and the rapid heat exchange during the heating process, and is also the installation reference structure of each MEMS inertial sensor and the cooling plate.

[0069] Device 36: MEMS inertial sensor.

[0070] Device 37: MEMS inertial sensor.

[0071] Device 38: MEMS inertial sensor.

[0072] Device 39: A MEMS inertial sensor circuit board, used for fixing and supporting the MEMS inertial sensor, the MEMS inertial sensor being welded on the MEMS inertial sensor circuit board.

[0073] Device 40: A MEMS inertial sensor circuit board, used for fixing and supporting the MEMS inertial sensor, the MEMS inertial sensor being welded on the MEMS inertial sensor circuit board.

[0074] Device 41: A MEMS inertial sensor circuit board, used for fixing and supporting the MEMS inertial sensor, the MEMS inertial sensor being welded on the MEMS inertial sensor circuit board.

[0075] In a possible embodiment, the controller includes a program that can execute the PID constant temperature control algorithm and a temperature detection program, wherein the program that can execute the PID constant temperature control algorithm and the temperature detection program are stored in the controller or transmitted to the controller through a communication channel outside the controller.

[0076] The controller may be a microcontroller unit (MCU) or a central processing unit (CPU). The controller includes a program that can execute the PID constant temperature control algorithm and a temperature detection program, wherein the program that can execute the PID constant temperature control algorithm and the temperature detection program can be stored in the controller by burning, or transmitted to the controller through a communication channel outside the controller. The controller can output a control signal based on the received temperature data and the PID constant temperature control algorithm.

[0077] In a possible embodiment, the control signal controls the power supply to output a forward current and a reverse current, wherein the current flow directions of the forward current and the reverse current are opposite. The power supply is a DC power output device, and under the control of the controller, the positive and negative directions of the power supply output current can be switched according to the control signal output by the controller, so that the power supply output current flows in opposite directions of the forward current and the reverse current, providing the cooling plate with a cooling forward current and a heating reverse current.

[0078] Specifically, a control signal is obtained according to the temperature of the heat conductive block collected by the temperature sensor and the threshold value set in the PID constant temperature control algorithm. When the temperature of the heat conductive block is lower than the low temperature threshold value, the control power supply outputs a reverse current to control the refrigeration plate to perform a heating operation; when the temperature of the heat conductive block is higher than the high temperature threshold value, the control power supply outputs a forward current to control the refrigeration plate to perform a cooling operation; when the temperature of the heat conductive block is between the low temperature threshold value and the high temperature threshold value, the refrigeration plate is powered off and no heating or cooling operation is performed.

[0079] In a possible embodiment, the temperature sensor is a contact temperature sensor, wherein the contact temperature sensor may be a PT100 or an NTC temperature sensor. The temperature sensor is used to measure the temperature of the heat conducting block, and there are many types of temperature sensor devices. In one example, the temperature sensor may be a PT100 or an NTC temperature sensor (Negative Temperature Coefficient). In practical applications, the measurement error of the temperature sensor is controlled within 5°C.

[0080] In a possible embodiment, the heat dissipation power of the radiator is not less than 2 times the maximum power of the cooling plate. The radiator needs to be installed on the cooling plate. In a high temperature environment, the cooling plate needs to be used to cool the heat conductive block, and the heat conductive block is used to achieve the effect of cooling the MEMS inertial sensor. In order to achieve a better cooling effect, it is necessary to ensure that the radiator has a good heat dissipation effect, and the heat dissipation power of the radiator usually needs to exceed 2 times the maximum power of the cooling plate.

[0081] In the embodiment of the present application, the heat dissipation power of the radiator is controlled within a range not less than 2 times the maximum power of the cooling plate, which can ensure that the radiator can dissipate heat for the cooling plate well and control the temperature of the heat conductive block within a smaller range of variation.

[0082] In a possible embodiment, the temperature sensor is mounted on one of the mounting surfaces of the heat conductive block or inside the heat conductive block. The temperature sensor is used to measure the temperature of the heat conductive block, and the temperature sensor can be mounted and fixed on a mounting surface of the heat conductive block by a heat conductive medium, such as heat conductive glue. The temperature of the surface of the heat conductive block is monitored by the temperature sensor. In order to achieve a better temperature measurement accuracy effect, the temperature sensor can also be installed inside the heat conductive block, and the method of installing it inside the heat conductive block makes the temperature value measured by the temperature sensor closer to the average temperature of the heat conductive block.

[0083] Compared with the thermostatic control device in the prior art, the thermostatic control device of the inertial navigation system provided in the embodiment of the present application has the following improvements: First, the heat dissipation method of the MEMS inertial sensor in the prior art is natural heat dissipation through the circuit board and the sensor surface, which is a passive heat dissipation method. The temperature of the MEMS inertial sensor will change with the change of the external temperature. The heat dissipation efficiency of the MEMS inertial sensor is low, and in practical application, its temperature change range is huge. The thermostatic control device in the present application belongs to a closed-loop negative feedback control system, which is composed of an active temperature control system through a controller, a temperature sensor, a power supply, a heat conductive block, a cooling plate and a radiator. The real-time temperature of the heat conductive block is collected by the temperature sensor, and the power supply is controlled according to the PID thermostatic control algorithm, and the cooling plate is further controlled to cool or heat the heat conductive block, and the real-time temperature of the MEMS inertial sensor is actively adjusted, and the temperature of the MEMS inertial sensor is controlled within a smaller fluctuation range. Secondly, in the prior art, the heat dissipation pathways of MEMS inertial sensors are independent and dispersed, and the heat dissipation efficiency of each MEMS inertial sensor is low and varies greatly, resulting in large heat accumulation in each MEMS inertial sensor and temperature imbalance between each other, which in turn has an adverse effect on the temperature drift and measurement error of the MEMS inertial sensor. In the present application, all MEMS inertial sensors are installed together with a heat conductive block, and the temperature is controlled by a common heat conductive block, so that the heat transfer efficiency of each MEMS inertial sensor is greatly improved, and the temperature of each sensor is kept consistent, thereby reducing temperature drift and measurement error, and reducing the difficulty of factory calibration. On the third aspect, the heat of the MEMS inertial sensor in the prior art is dissipated through the circuit board connected to it, and its temperature is also greatly affected by the ambient temperature and will change with the change of the ambient temperature. Usually, the working environment of industrial-grade applications is -40℃~85℃, which causes the temperature variation range of the sensor to exceed 120℃. The present application uses an active temperature control system composed of a controller, a temperature sensor, a power supply, a heat conductive block, a cooling plate and a radiator to achieve a two-way thermal regulation function for heat dissipation and heating of the MEMS inertial sensor, and controls the temperature change of the MEMS inertial sensor during long-term operation within a smaller temperature variation range, for example, the temperature variation range of the sensor is controlled within 20℃, which can greatly improve the problem of large measurement errors caused by large temperature drift of the MEMS inertial sensor in the inertial navigation system.

[0084] The constant temperature control device of the inertial navigation system provided in the present application can improve the thermal conduction efficiency of the MEMS inertial sensor by 20 to 200 times through the heat conductive block. In addition, an active temperature control system is composed of a controller, a temperature sensor, a power supply, a heat conductive block, a cooling plate and a heat sink, so that the temperature change of the MEMS inertial sensor during long-term operation can be controlled within a smaller temperature change range, thereby achieving the effect of reducing the temperature drift of the MEMS inertial sensor, and the inertial measurement error of the final inertial navigation system can be reduced by half, thereby improving the measurement accuracy of the inertial navigation system.

[0085] See also Figure 5 The present application also provides a method for controlling the temperature of an inertial navigation system, the method comprising: S1, collect temperature data of the heat conducting block.

[0086] S2: output a control signal according to the temperature data and based on a PID constant temperature control algorithm.

[0087] S3, using the control signal to control the refrigeration plate to perform a heating operation or a cooling operation.

[0088] The present application forms an active temperature control system through a controller, a temperature sensor, a power supply, a heat conductive block, a cooling plate and a heat sink. By collecting the temperature data of the heat conductive block in real time and outputting a control signal according to the PID constant temperature control algorithm of the temperature data, the cooling plate is controlled to perform heating or cooling operations. The temperature of the MEMS inertial sensor can be actively adjusted according to the working temperature of the MEMS inertial sensor, so that the temperature of the MEMS inertial sensor can be controlled within a smaller fluctuation range.

[0089] In a possible embodiment, the above step S2 includes: S21, judging whether a heating operation or a cooling operation is required according to the temperature data and based on a PID constant temperature control algorithm.

[0090] S22: If yes, output a control signal corresponding to the heating operation or the cooling operation.

[0091] S23, if not, return to step S1: collect temperature data of the heat conducting block.

[0092] See also Figure 6 , Figure 6A flow chart of a constant temperature control method for an inertial navigation device provided in the present application, when the controller controls the heat conductive block to be in a constant temperature state, it is necessary to first collect the temperature of the heat conductive block through a temperature sensor, and decide whether to start the refrigeration plate for heating or cooling operation according to the temperature of the heat conductive block. In an example, the controller can set the PID constant temperature control threshold to a high temperature threshold not higher than 35°C and a low temperature threshold not lower than 15°C, that is, the target temperature range of the heat conductive block is controlled at 15°C~35°C. After the system is powered on, when the temperature of the heat conductive block rises from below 35°C to above 35°C due to the increase in ambient temperature and the operating temperature of the MEMS inertial sensor, the refrigeration plate is started for cooling operation; when the temperature of the heat conductive block drops from above 15°C to below 15°C due to the decrease in ambient temperature, the refrigeration plate is started for heating operation; when the temperature of the heat conductive block is between 15°C~35°C, the temperature is moderate at this time, the controller stops the constant temperature control function, and only continuously monitors the temperature of the heat conductive block, at this time, the MEMS inertial sensor dissipates heat naturally.

[0093] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A constant temperature control device for an inertial navigation system, characterized in that: The constant temperature control device comprises: MEMS inertial sensor, heat conduction block, controller, temperature sensor, cooling sheet, heat sink and power supply; the heat conduction block has multiple mounting surfaces, at least three of the multiple mounting surfaces are orthogonal to each other; The MEMS inertial sensor is mounted on three mounting surfaces orthogonal to each other through a heat-conducting medium, the first side surface of the cooling plate is mounted on one of the mounting surfaces through a heat-conducting medium, the second side surface of the cooling plate is mounted with the radiator through a heat-conducting medium, and the temperature sensor is mounted on the heat-conducting block, wherein the first side surface and the second side surface are two opposite side surfaces of the cooling plate; The controller is electrically connected to the temperature sensor and the power supply respectively, and the power supply is electrically connected to the refrigeration plate; The temperature sensor is used to collect the temperature of the heat conducting block and transmit the collected temperature data to the controller; The controller is used to receive the temperature data, output a control signal based on a PID constant temperature control algorithm, and transmit the control signal to the power supply; The power supply is used to receive the control signal and use the control signal to control the refrigeration plate to perform a heating operation or a cooling operation.

2. The constant temperature control device according to claim 1, characterized in that: The material of the heat conducting block is metal material or polymer material with heat conducting property.

3. The constant temperature control device according to claim 1, characterized in that: The top of each MEMS inertial sensor is mounted on the mounting surface via a heat-conducting medium, and the circuit board of the MEMS inertial sensor is mounted on the bottom of each MEMS inertial sensor.

4. The constant temperature control device according to claim 1, characterized in that: The radiator is provided with a heat dissipation structure, and the heat dissipation structure includes at least one of a heat dissipation fin, a heat dissipation hole and a heat dissipation tooth.

5. The constant temperature control device according to claim 1, characterized in that: The controller includes a program capable of executing the PID constant temperature control algorithm and a temperature detection program, wherein the program capable of executing the PID constant temperature control algorithm and the temperature detection program are stored in the controller or transmitted to the controller via a communication channel outside the controller.

6. The constant temperature control device according to claim 4, characterized in that: The radiator is a shell, and the heat dissipation structure is arranged on the surface of the shell.

7. The constant temperature control device according to claim 1, characterized in that: The control signal controls the power supply to output a forward current and a reverse current, wherein the forward current and the reverse current flow in opposite directions.

8. The constant temperature control device according to claim 1, characterized in that: The temperature sensor is mounted on one of the mounting surfaces of the heat conducting block or inside the heat conducting block.

9. A constant temperature control method for an inertial navigation system, characterized in that: The method comprises: Collect temperature data of the heat conducting block; Output a control signal according to the temperature data and based on a PID constant temperature control algorithm; The control signal is used to control the refrigeration plate to perform a heating operation or a cooling operation.

10. The constant temperature control method according to claim 9, characterized in that: Outputting a control signal according to the temperature data and based on a PID constant temperature control algorithm includes: According to the temperature data and based on the PID constant temperature control algorithm, determine whether a heating operation or a cooling operation is required; If so, output a control signal corresponding to a heating operation or a cooling operation; If not, return to the execution step: collect temperature data of the heat conducting block.

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