IMU calibration method and device

Abstract

The invention discloses an IMU (Inertial Measurement Unit) calibration method and device, relates to the technical field of intelligent driving, and can improve the accuracy of an IMU calibration result. The method is applied to equipment comprising an IMU and comprises the steps that under the condition that the equipment is in a static state, the temperature of the environment where the IMU is located is collected, the IMU is used for measuring the angular velocity of the equipment in a moving state, then the temperature of the IMU is increased from the environment temperature to the target temperature, and then the angular velocity deviation measured by the IMU with the temperature being the target temperature is determined; and finally, calibrating the temperature excursion of the IMU based on the angular velocity offset.

Description

Technical Field

[0001] The present application relates to the field of intelligent driving technology, and in particular to an IMU calibration method and device. Background Art

[0002] In the field of intelligent driving, the inertial measurement unit (IMU) is an important component for realizing the vehicle positioning function. IMU can measure the acceleration, angular velocity and other information of the vehicle in real time to estimate the vehicle's position and ensure the vehicle's driving safety.

[0003] Since high-precision IMUs are expensive, the industry usually uses low-cost IMUs for vehicle positioning. The accuracy of the low-cost IMUs is also relatively low, so the temperature drift of the IMU needs to be calibrated to improve the accuracy of the vehicle's angular velocity when the IMU is used after leaving the factory. The current calibration solution is to use a temperature box to heat the IMU during the production line period, determine the temperature drift of the IMU, and calibrate the IMU. However, the temperature box has vibrations, which makes the calibration results of the IMU less accurate. Summary of the invention

[0004] The present application provides an IMU calibration method and device, which can improve the accuracy of IMU calibration results.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect, an IMU calibration method is provided, which is applied to a device including an IMU, the method comprising: when the device is in a stationary state, collecting the ambient temperature of the IMU, the IMU being used to measure the angular velocity of the device when it is in motion; raising the temperature of the IMU from the ambient temperature to a target temperature; determining the angular velocity offset measured by the IMU when the temperature is the target temperature; and calibrating the temperature drift of the IMU based on the angular velocity offset.

[0007] Based on the above technical solution, when the device is stationary, the included IMU is heated from the ambient temperature to the target temperature, and the angular velocity offset measured by the IMU at the target temperature can be used to calibrate the IMU temperature drift. The IMU is used to measure the angular velocity when the device is in motion, that is, the device can self-heat the IMU, thereby realizing automatic calibration of the IMU. There is no need to calibrate the IMU through an additional temperature box, etc., which improves the efficiency of IMU calibration and the accuracy of the calibration results.

[0008] In one possible design, the target temperature is the operating temperature of the IMU when measuring the angular velocity of the device in motion. Based on this design, the IMU is heated from ambient temperature to operating temperature, and the angular velocity offset of the IMU at the operating temperature can be determined, and the temperature drift of the IMU at the operating temperature can be calibrated. In this way, when the IMU is working, that is, when measuring the angular velocity of the device in motion, a more accurate angular velocity can be obtained, thereby improving the accuracy of the IMU when working.

[0009] In one possible design, the target temperature is the highest operating temperature when the IMU measures the angular velocity of the device in motion; the angular velocity offset measured by the IMU with the determined temperature being the target temperature includes: determining the angular velocity offset measured by the IMU at each temperature from the ambient temperature to the target temperature. Based on this design, the temperature of the IMU may have a heating process when it is working, that is, the IMU may have multiple operating temperatures. The angular velocity offset of the IMU at different operating temperatures is determined, and then the angular velocity temperature drift of the IMU at different operating temperatures can be calibrated. In this way, when the IMU at different operating temperatures measures the angular velocity of a device in motion, a more accurate angular velocity can be obtained, which can further improve the accuracy of the IMU at work.

[0010] In a possible design, the collecting of the ambient temperature of the IMU includes: collecting the ambient temperature of the IMU through an ambient temperature collection circuit included in the device. Based on this design, the self-collection of the ambient temperature of the IMU can be achieved.

[0011] In a possible design, the ambient temperature acquisition circuit includes a pull-up resistor and a negative temperature coefficient resistor. Based on this design, the ambient temperature of the IMU is acquired through the pull-up resistor and the negative temperature coefficient resistor, so that the ambient temperature of the IMU can be stably acquired.

[0012] In one possible design, the step of heating the IMU from the ambient temperature to the target temperature includes: heating the IMU from the ambient temperature to the target temperature by a heating circuit included in the device. Based on this design, automatic heating of the IMU can be achieved.

[0013] In one possible design, the heating circuit includes a power driver and a surface mounted power resistor. Based on this design, the IMU can be quickly and automatically heated.

[0014] In a possible design, in the process of raising the temperature of the IMU from the ambient temperature to the target temperature, the method further includes: measuring the temperature of the IMU through a temperature sensor in the IMU. Based on this design, the temperature of the IMU may be different from the ambient temperature of the IMU, so collecting the temperature of the IMU through the temperature sensor in the IMU can improve the accuracy of the obtained IMU temperature and further improve the accuracy of the calibration result.

[0015] In a possible design, before measuring the temperature of the IMU through the temperature sensor in the IMU, the method further includes: calibrating the temperature sensor in the IMU based on the ambient temperature. Based on this design, when the device is stationary, the temperature value of the temperature sensor in the IMU may be inconsistent with the current ambient temperature. Therefore, the temperature sensor in the IMU is first calibrated based on the ambient temperature, and then the temperature of the IMU obtained by the temperature sensor in the IMU can be more accurate during the process of heating the IMU.

[0016] In a possible design, before collecting the ambient temperature of the IMU, the method further includes: determining a sudden change in the ambient temperature of the IMU. Based on this design, when the ambient temperature suddenly changes, the temperature drift of the IMU calibrated before the sudden change may no longer be applicable to the temperature drift of the IMU after the sudden change. Therefore, calibrating the IMU in the case of a sudden change in ambient temperature can make the calibration result unaffected by the sudden change in ambient temperature, further improving the accuracy of the calibration result.

[0017] In the second aspect, an IMU calibration device is provided, the IMU calibration device includes a module or unit corresponding to the above method, and the module or unit can be implemented by hardware, software, or by hardware executing the corresponding software. In a possible design, the IMU calibration device includes an acquisition unit (or acquisition module), a heating unit (or heating module) and a processing unit (or processing module); the acquisition unit is used to collect the ambient temperature of the IMU installed in the device when the device including the IMU calibration device is in a stationary state, and the IMU is used to measure the angular velocity of the device when it is in motion; the heating unit is used to increase the temperature of the IMU from the ambient temperature to the target temperature; the processing unit is used to determine the angular velocity offset measured by the IMU with a temperature of the target temperature; the processing unit is also used to calibrate the temperature drift of the IMU based on the angular velocity offset.

[0018] In one possible design, the IMU installed on the device is included in the IMU calibration device.

[0019] In one possible design, the IMU installed in the device is not included in the IMU calibration device.

[0020] In one possible design, the target temperature is the operating temperature of the IMU when measuring the angular velocity of the device in motion.

[0021] In one possible design, the target temperature is the maximum operating temperature when the IMU measures the angular velocity of the device in motion; the processing unit has a function for determining the angular velocity offset measured by the IMU at each temperature from the ambient temperature to the target temperature.

[0022] In one possible design, the processing unit is also used to determine a sudden change in the ambient temperature of the IMU.

[0023] In the third aspect, a chip for IMU calibration is provided, including an MCU, a heating circuit, an ambient temperature acquisition circuit and an IMU, wherein the MCU, the heating circuit, the ambient temperature acquisition circuit and the IMU are connected; the MCU is used to: when the device including the chip is in a stationary state, collect the ambient temperature of the IMU through the ambient temperature acquisition circuit, and the IMU is used to measure the angular velocity of the device when it is in motion; drive the heating circuit to raise the temperature of the IMU from the ambient temperature to the target temperature; determine the angular velocity offset measured by the IMU with a temperature of the target temperature; and calibrate the temperature drift of the IMU based on the angular velocity offset. Optionally, the IMU may not be included in the chip. Optionally, the MCU may also be implemented as other types of processors.

[0024] In one possible design, the target temperature is the operating temperature of the IMU when measuring the angular velocity of the device in motion.

[0025] In one possible design, the target temperature is the maximum operating temperature of the IMU when measuring the angular velocity of a device in motion; the MCU is specifically used to determine the angular velocity offset measured by the IMU at each temperature from the ambient temperature to the target temperature.

[0026] In a possible design, the ambient temperature acquisition circuit includes a pull-up resistor and a negative temperature coefficient resistor.

[0027] In one possible design, the heating circuit includes a power driver and a surface-mounted power resistor.

[0028] In a possible design, in the process of driving the heating circuit to raise the temperature of the IMU from the ambient temperature to the target temperature, the MCU is also used to measure the temperature of the IMU through a temperature sensor in the IMU.

[0029] In one possible design, before measuring the temperature of the IMU through the temperature sensor in the IMU, the MCU is also used to calibrate the temperature sensor in the IMU based on the ambient temperature.

[0030] A possible design also includes a power supply, which is used to power the MCU, the heating circuit, the ambient temperature acquisition circuit and the IMU.

[0031] In a fourth aspect, an IMU calibration device is provided, comprising a processor and a memory, wherein the memory is coupled to the processor, the memory is used to store computer program code, the computer program code includes computer instructions, and the processor reads the computer instructions from the memory so that the IMU calibration device executes the method as described in any one of the designs in the first aspect above. Optionally, the memory may be coupled to the processor or may be independent of the processor.

[0032] In a possible design, it also includes at least one of a heating circuit and an ambient temperature acquisition circuit; the ambient temperature acquisition circuit is used to collect the ambient temperature of the IMU; the heating circuit is used to raise the temperature of the IMU from the ambient temperature to the target temperature.

[0033] In one possible design, the IMU calibration device further includes a communication interface, which can be used for the IMU calibration device to communicate with other devices. Exemplarily, the communication interface can be a transceiver, an input / output interface, an interface circuit, an output circuit, an input circuit, a pin or a related circuit, etc.

[0034] In a fifth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium includes a computer program. When the computer program runs on an IMU calibration device, the IMU calibration device executes a method as described in any one of the designs in the first aspect above.

[0035] In a sixth aspect, a computer program product is provided, the computer program product comprising: a computer program or instructions, when the computer program or instructions are run on a computer, the computer executes a method as described in any one of the designs of the first aspect above.

[0036] In the seventh aspect, a chip system is provided, comprising at least one processor and at least one interface circuit, wherein the at least one interface circuit is used to perform transceiver functions and send instructions to at least one processor, and when the at least one processor executes the instructions, the at least one processor executes a method as described in any one of the designs in the first aspect above.

[0037] It should be noted that the technical effects brought about by any design in the above-mentioned second to seventh aspects can refer to the technical effects brought about by the corresponding design in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application;

[0039] Figure 2 A schematic diagram of the structure of a calibration device provided in an embodiment of the present application;

[0040] Figure 3 A schematic diagram of the structure of another calibration device provided in an embodiment of the present application;

[0041] Figure 4a A schematic diagram of the structure of another calibration device provided in an embodiment of the present application;

[0042] Figure 4b A schematic diagram of the structure of another calibration device provided in an embodiment of the present application;

[0043] Figure 5 A flowchart of an IMU calibration method provided in an embodiment of the present application;

[0044] Figure 6 A schematic diagram of the structure of an IMU calibration device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] At present, when using IMU, the industry will calibrate the angular velocity temperature drift of IMU to improve the accuracy of IMU. Among them, the drift of the angular velocity zero point of IMU caused by temperature change is called the temperature drift of IMU angular velocity, which can be referred to as the angular velocity temperature drift of IMU. The current calibration scheme is to use a temperature box to heat up the IMU during the production line period, determine the temperature drift of IMU and calibrate the IMU. However, the temperature box has vibrations, which makes the accuracy of the IMU calibration result low. And the temperature cycle time of the temperature box is long, which makes the calibration time of IMU longer and the calibration efficiency is low. In addition, since the calibration is performed on the production line, the IMU can only be calibrated once, and the temperature drift of IMU may change slowly over time, so the calibration result of the production line may no longer be applicable to the temperature drift of IMU after the change, which will further reduce the accuracy of IMU.

[0046] Based on this, an embodiment of the present application provides an IMU calibration method, which can improve the efficiency of IMU calibration, improve the accuracy of IMU calibration results, and improve the precision of IMU.

[0047] The technical solution provided in the embodiments of the present application can be applied to various devices including IMU. For example, the device may include but is not limited to vehicles, drones, artificial intelligence (AI) devices, augmented reality (AR) devices, virtual reality (VR) devices, handheld devices, wearable devices, and other devices.

[0048] The following takes the device as a vehicle as an example. Figure 1 A schematic structural diagram of a vehicle 100 provided in an embodiment of the present application is shown.

[0049] The vehicle 100 may include various subsystems, such as a travel system 110, a sensor system 120, a control system 130, one or more peripheral devices 140, a power source 150, a computer system 160, and a user interface 170. Optionally, the vehicle 100 may include more or fewer subsystems, and each subsystem may include multiple elements. In addition, each subsystem and element of the vehicle 100 may be interconnected by wire or wirelessly.

[0050] The travel system 110 includes components that provide powered movement for the vehicle 100. In one embodiment, the travel system 110 includes one or more of an engine 111, a transmission 112, an energy source 113, and wheels 114.

[0051] The sensor system 120 may include several sensors that sense information about the environment around the vehicle 100. For example, the sensor system 120 includes a positioning system 121 (the positioning system may be a global positioning system (GPS), or a Beidou system or other positioning systems), an inertial measurement unit (IMU) 122, a radar 123, a lidar 124, and a camera 125. Sensor data from one or more of these sensors may be used to detect objects and their corresponding characteristics (position, shape, direction, speed, etc.). Such detection and recognition are key functions for the safe operation of the vehicle 100 autonomous driving.

[0052] IMU 122 is used to sense the position and orientation changes of vehicle 100 based on inertial acceleration. In one embodiment, IMU can measure the acceleration and angular velocity of vehicle 100, such as IMU 122 can be specifically implemented as a combination of accelerometer and gyroscope. An IMU can include one or more accelerometers, and one or more gyroscopes. Accelerometers in different directions can detect acceleration signals of vehicle 100 in different directions, and gyroscopes in different directions can detect angular velocity signals of vehicle 100 in different directions. Then, IMU 122 can determine the acceleration and angular velocity of vehicle 100 in three-dimensional space based on the detected acceleration signals and angular velocity signals, and solve the posture of vehicle 100.

[0053] In some embodiments of the present application, the IMU 122 may be included in a calibration device 200, and the calibration device 200 may be used to calibrate the angular velocity temperature drift of the IMU. For example, the calibration device 200 may be a module, a module, a component, or a chip built into the vehicle 100 as one or more components or units. For example, Figure 2 A schematic structural diagram of a calibration device 200 provided in an embodiment of the present application is shown.

[0054] like Figure 2 As shown, the calibration device 200 may include a microcontroller unit (MCU) 201, a heating circuit 202 (or a heating module 202), an ambient temperature acquisition circuit 203 (or an ambient temperature acquisition module 203), an IMU 122, etc. The MCU 201, the heating circuit 202, and the ambient temperature acquisition circuit 203 are connected to the IMU 122.

[0055] Among them, MCU201 can be used to read the temperature value of the ambient temperature acquisition circuit 203 after startup, and determine the ambient temperature of the IMU122 according to the temperature value. The ambient temperature of the IMU122 can refer to the temperature of the single board where the IMU122 is located. In some embodiments, MCU201 can also be used to calibrate the temperature sensor inside the IMU122 based on the read temperature value.

[0056] In some embodiments, the MCU may also receive instructions from the vehicle 100, such as receiving instructions from the computer system 160 of the vehicle 100, to determine whether to start the IMU calibration process according to the received instructions. Alternatively, the MCU may pre-store relevant instructions or data, and the MCU may determine when to start the IMU calibration process based on the pre-stored relevant instructions or data.

[0057] It can be understood that in this embodiment, MCU is taken as an example. In other embodiments, MCU can also be implemented as other processors, such as: (central processing unit, CPU), application specific integrated circuit (ASIC) or other processors.

[0058] The ambient temperature acquisition circuit 203 may be used to acquire the ambient temperature of the IMU 122. The heating circuit 202 may be used to heat the IMU 122 to raise the temperature of the IMU 122 to a specified temperature. The IMU 122 may be used to measure the angular velocity deviation of the vehicle 100 at different temperatures.

[0059] Optionally, the calibration device 200 may further include a power supply 204. The power supply 204 may be used to power the MCU 201, the heating circuit 202, the ambient temperature acquisition circuit 203, the IMU 122, etc. Optionally, the number of the power supplies may be one or more. In the calibration device 200, different devices may be powered by different power supplies or by the same power supply. It is to be understood that in this embodiment, the calibration device 200 and other components in the vehicle 100 are taken as an example of using different power supplies. In other embodiments, the calibration device 200 may also use the same power supply as other components in the vehicle 100. For example, the components in the calibration device 200 may also be powered by Figure 1 A power supply 150 is shown to provide power.

[0060] Understandably, Figure 2 The example in which the IMU 122 is included in the calibration device 200 is taken as an example. In other embodiments, Figure 3 As shown, the calibration device 200 may not include the IMU 122. The calibration device 200 is connected to the IMU 122. Figure 3 For an introduction to each module in the calibration device 200 shown in FIG. Figure 2 An introduction to the corresponding modules in the calibration device 200 is shown.

[0061] In some embodiments, the heating circuit 202 may include a power driver and a surface mount power resistor, and the power driver is connected in series with the surface mount power resistor. Among them, the power driver can drive the surface mount power resistor to heat the IMU122. The ambient temperature acquisition circuit 203 may include at least one of a negative temperature coefficient resistor and a pull-up resistor. Optionally, when a negative temperature coefficient resistor and a pull-up resistor are included at the same time, the negative temperature coefficient resistor and the pull-up resistor can be connected in series to achieve stable acquisition of the ambient temperature of the IMU122.

[0062] In this embodiment, Figure 4aFIG. 2 shows a schematic diagram of the structure of another calibration device 200 provided in an embodiment of the present application. Figure 4a As shown, the heating circuit 202 described above may include a power driver, a surface mount power resistor 1 and a surface mount power resistor 2, the power driver is respectively connected in series with the surface mount power resistor 1 and the surface mount power resistor 2, and the power driver is connected to the MCU 201, and the surface mount power resistor 1 and the surface mount power resistor 2 may be mounted on the IMU 122. The MCU 201 may send a (pulse width modulation, PWM) signal to drive the power driver to heat the surface mount power resistor 1 and the surface mount power resistor 2, thereby achieving the temperature increase of the IMU 122.

[0063] Understandably, Figure 4a Two surface-mount power resistors are used as an example. In actual applications, more or less than two surface-mount power resistors may be used, and the embodiment of the present application does not impose any specific restrictions on the installation positions of the surface-mount power resistors on the IMU 122.

[0064] like Figure 4a As shown, the above-mentioned ambient temperature acquisition circuit 203 can be specifically implemented as a pull-up resistor and a negative temperature coefficient resistor, which are connected in series and connected to the MCU 201. The MCU 201 can read the resistance value, voltage value, etc. of the pull-up resistor and the negative temperature coefficient resistor, and then determine the ambient temperature of the IMU 122.

[0065] Understandably, Figure 4a It is taken as an example that the calibration device includes two power supplies. In actual applications, more or fewer power supplies may be included.

[0066] Optionally, the calibration device 200 may also be configured by Figure 4b The device shown is implemented. Figure 4b FIG. 2 is a schematic diagram of the structure of another calibration device 200 provided in an embodiment of the present application. Figure 4b As shown, the calibration device 200 includes at least one processor 401 , a communication line 402 , a memory 403 and at least one communication interface 404 .

[0067] The processor 401 may be a general-purpose CPU, MCU, microprocessor, ASIC, or one or more integrated circuits for controlling the execution of the program of the present application. The processor 401 may be used to execute the scheme for calibrating the IMU described in the embodiment of the present application.

[0068] The communication link 402 may include a pathway to transmit information between the above-mentioned components.

[0069] The communication interface 404 is used to communicate with other devices or components. In the embodiment of the present application, the communication interface 404 can be a module, a circuit, a bus, an interface, a transceiver or other device that can realize the communication function. Optionally, when the communication interface is a transceiver, the transceiver can be an independently arranged transmitter, which can be used to send information to other devices, and the transceiver can also be an independently arranged receiver for receiving information from other devices. The transceiver can also be a component that integrates the functions of sending and receiving information, and the embodiment of the present application does not limit the specific implementation of the transceiver.

[0070] The memory 403 may be any form of storage medium, such as random access memory (RAM) or electrically erasable programmable read-only memory (EEPROM). The memory 403 may exist independently and be connected to the processor 401 via the communication line 402. The memory 403 may also be integrated with the processor 401.

[0071] The memory 403 is used to store execution instructions for implementing the solution of the present application, and the execution is controlled by the processor 401. The processor 401 is used to execute the execution instructions stored in the memory 403, thereby implementing the method provided in the following embodiments of the present application.

[0072] In some embodiments, such as Figure 4b The calibration device 200 shown may not include an ambient temperature acquisition circuit, a heating circuit, an IMU, etc. The calibration device 200 may communicate with the ambient temperature acquisition circuit, the heating circuit, the IMU, etc. through the communication interface 404, etc., so as to implement the method provided in the embodiment of the present application.

[0073] In other embodiments, such as Figure 4b The calibration device 200 shown may include one or more of an ambient temperature acquisition circuit 405, a heating circuit 406, and an IMU 407. The ambient temperature acquisition circuit 405, the heating circuit 406, the IMU 407, etc. may be connected to other components via a communication line 402, thereby implementing the method provided in the embodiment of the present application. For an introduction to the ambient temperature acquisition circuit 405, the heating circuit 406, and the IMU 407, please refer to Figure 2 Introduction to the corresponding module in.

[0074] In some embodiments, such as Figure 4b The calibration device 200 shown may not include a power supply, and the calibration device 200 may be powered by a power supply in other devices. Figure 4bThe calibration device 200 shown may include a power supply, which can supply power to various components of the calibration device 200 .

[0075] The control system 130 may control the operation of the vehicle 100 and its components. The control system 130 may include various elements, such as one or more of a steering system 131, a throttle 132, a brake unit 133, a computer vision system 134, a path control system 135, and an obstacle avoidance system 136.

[0076] The vehicle 100 interacts with external sensors, other vehicles, other computer systems or users through the peripheral device 140. For example, the peripheral device 140 may include one or more of a wireless communication system 141, an onboard computer 142, a microphone 143 and / or a speaker 144.

[0077] The power source 150 may provide power to various components of the vehicle 100. Some or all functions of the vehicle 100 are controlled by a computer system 160. The computer system 160 may include at least one processor 161 that executes instructions 1621 stored, for example, in a data storage device 162. The computer system 160 may also be a plurality of computing devices that control independent components or subsystems of the vehicle 100 in a distributed manner.

[0078] Processor 161 may be any conventional processor, such as a CPU or an ASIC or other dedicated hardware-based processor.

[0079] In some embodiments, data storage device 162 may include instructions 1621 (e.g., program logic) that may be executed by processor 161 to perform various functions of vehicle 100, including those described above. Data storage device 162 may also include additional instructions, including instructions to send data to, receive data from, interact with, and / or control one or more of travel system 110, sensor system 120, control system 130, and peripheral device 140.

[0080] In addition to the instructions 1621, the data storage device 162 may also store data such as road maps, route information, the vehicle's location, direction, speed, and other such vehicle data, and other information. Such information may be used by the vehicle 100 and the computer system 160 during operation of the vehicle 100 in autonomous, semi-autonomous, and / or manual modes.

[0081] The user interface 170 is used to provide information to or receive information from a user of the vehicle 100. The computer system 160 can control the vehicle 100 based on information obtained from various subsystems (eg, the travel system 110, the sensor system 120, and the control system 130) and information received from the user interface 170.

[0082] Alternatively, one or more of the above components may be installed or associated separately from the vehicle 100. For example, the data storage device 162 may be partially or completely separate from the vehicle 100. The above components may be coupled together for communication by wire and / or wireless means.

[0083] Optionally, the above components are only examples. In actual applications, the components in the above modules may be added or deleted according to actual needs. Figure 1 It should not be understood as limiting the embodiments of the present application.

[0084] The vehicle 100 may be a car, a truck, a motorcycle, a bus, a ship, an airplane, a helicopter, a lawn mower, an entertainment vehicle, an amusement park vehicle, construction equipment, a tram, a golf cart, a train, etc., and the embodiments of the present application do not make any particular limitation.

[0085] In other embodiments of the present application, the vehicle 100 may further include a hardware structure and / or a software module to implement the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether one of the above functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.

[0086] For example, Figure 5 An IMU calibration method provided by an embodiment of the present application is shown, and the execution subject of the method can be a device including an IMU, or a processor in the device. Figure 5 As shown, the method comprises the following steps:

[0087] S501. When the device is in a stationary state, collect the ambient temperature of the IMU.

[0088] Optionally, when the device is in a stationary state, it can be in a state of being started but not moving, or in a non-started state. For example, when the device is a vehicle, the vehicle can be in a state of being ignited but not moving, or in a state of being off. Another example: when the device is an AI device, the AI ​​device can be in a stationary state, it can be in a state of being turned on or in standby but not moving, or in a state of being turned off.

[0089] Among them, IMU can be used to measure the angular velocity of the device when it is in motion. Optionally, when the device undergoes various movements such as displacement and rotation, such as: vehicle driving, turning, etc., AI device rotation, movement, etc., the device is in motion.

[0090] It can be understood that the ambient temperature of the IMU may refer to the temperature of the board where the IMU is located. When the IMU is not working, the temperature of the IMU may be the same as the temperature of the board where the IMU is located.

[0091] In some embodiments, the device includes an ambient temperature acquisition circuit, and the device can acquire the ambient temperature of the IMU through the ambient temperature acquisition circuit. Optionally, the ambient temperature acquisition circuit can include a pull-up resistor and a negative temperature coefficient resistor. In this way, stable acquisition of the ambient temperature of the IMU can be achieved.

[0092] S502: Raise the temperature of the IMU from the ambient temperature to the target temperature.

[0093] In some embodiments, the target temperature may be an operating temperature when the IMU measures the angular velocity of a device in motion.

[0094] In a specific scenario, taking the device as a vehicle, when the vehicle starts running, the temperature of the IMU will gradually rise to the operating temperature, such as 20 degrees Celsius. In this way, when the vehicle is driving, if there is no external correction source (such as real-time kinematic measurement (RTK), global navigation satellite system (GNSS) and other absolute positioning systems, etc.), the IMU at the operating temperature at this time will be inaccurate due to the existence of temperature drift, and the measured angular velocity will not meet the requirements for vehicle positioning. Therefore, in this scenario, the temperature of the IMU can be raised from the ambient temperature to the operating temperature.

[0095] In other embodiments, the target temperature may be the maximum operating temperature when the IMU measures the angular velocity of a device in motion. In some scenarios, the operating temperature of the IMU may be different when it is working. Therefore, in this scenario, the temperature of the IMU may be raised from the ambient temperature to the maximum operating temperature. Optionally, the maximum operating temperature may be related to the power consumption of the board where the IMU is located and the temperature of the environment in which the device is located.

[0096] In some embodiments, the device may include a heating circuit that can heat the temperature of the IMU from the ambient temperature to the target temperature. Optionally, the heating circuit may include a power driver and a surface mounted power resistor. In this way, the rapid heating of the IMU can be automatically achieved.

[0097] In some embodiments, during the heating process, the temperature of the IMU may be collected by an ambient temperature collection circuit. In other embodiments, since the temperature of the IMU may be different from the ambient temperature of the IMU during the heating process, in order to improve the accuracy of the measured IMU temperature, the temperature of the IMU may be measured by a temperature sensor in the IMU.

[0098] In some embodiments, to further improve the accuracy of the measured temperature of the IMU, before measuring the temperature of the IMU through the temperature sensor in the IMU, the temperature sensor in the IMU may be calibrated based on the ambient temperature of the IMU. For example, the temperature value of the temperature sensor in the IMU is set to the ambient temperature of the IMU to calibrate it.

[0099] S503: Determine the angular velocity offset measured by the IMU when the temperature is the target temperature.

[0100] In some embodiments, only the angular velocity offset measured by the IMU whose temperature is the target temperature may be determined. For example, in combination with the scenario described above where the target temperature is the operating temperature of the IMU, in this scenario, only the angular velocity offset measured by the IMU whose temperature is the target temperature may be determined.

[0101] In other embodiments, the angular velocity offset measured by the IMU at each temperature from the ambient temperature to the target temperature may be determined. For example, in combination with the scenario of the highest operating temperature of the target temperature IMU described above, in this scenario, the angular velocity offset measured by the IMU at each temperature from the ambient temperature to the highest ambient temperature may be determined.

[0102] S504: Calibrate the temperature drift of the IMU based on the angular velocity offset.

[0103] In some embodiments, when only the angular velocity offset measured by the IMU at the target temperature is determined, the temperature drift of the IMU may be calibrated based on the acceleration offset measured by the IMU at the target temperature.

[0104] In other embodiments, when the angular velocity offset measured by the IMU at each temperature from the ambient temperature to the target temperature is determined, the temperature drift of the IMU can be calibrated based on the angular velocity offset measured by the IMU at each temperature. For example, the temperature drift of the IMU at 30 degrees Celsius can be calibrated based on the angular velocity measured by the IMU at 30 degrees Celsius, and the temperature drift of the IMU at 20 degrees Celsius can be calibrated based on the angular velocity measured by the IMU at 20 degrees Celsius.

[0105] Based on the above technical solution, when the device is stationary, the IMU can be calibrated by heating the installed IMU from the ambient temperature to the target temperature, and the angular velocity offset measured by the IMU at the target temperature can be used to measure the angular velocity of the device when it is in motion. In this way, the device can self-heat the IMU, thereby realizing the automatic calibration of the IMU. There is no need to calibrate the IMU through an additional temperature box, etc., which improves the efficiency of IMU calibration and the accuracy of the calibration results.

[0106] In some scenarios, as the IMU is used, the temperature drift of the IMU may change slowly over time, and the previous calibration results may no longer be able to resolve the temperature drift of the IMU after the change. Therefore, in order to further improve the accuracy of the calibration results, you can periodically (for example, once a year) perform such as Figure 5 The calibration scheme shown is used to improve the accuracy of the IMU. In this way, it can be ensured that during the life cycle of the IMU, the calibration result is not affected by the temperature drift of the IMU over time, so that the calibration result can still solve the temperature drift of the IMU after the offset occurs, and provide the accuracy of the IMU.

[0107] In other scenarios, such as sudden changes in ambient temperature (for example, from 6 to 20 degrees Celsius to -9 to 0 degrees Celsius), the calibration results before the sudden change in ambient temperature may no longer be applicable to the IMU after the sudden change in ambient temperature. Figure 5 The scheme shown is used to calibrate the IMU. In this way, the calibration result can be free from the influence of sudden changes in ambient temperature, further improving the accuracy of the calibration result.

[0108] In some other scenarios, in order to avoid inconvenience to users when calibrating the IMU, you can choose to perform operations such as Figure 5 For example, when the vehicle is started but not driving, when the vehicle is stopped at night, when the vehicle is stopped in the garage, before the production line vehicle leaves the factory, etc., you can use the calibration scheme shown in the figure. Figure 5 The scheme shown is used to calibrate the IMU.

[0109] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of the method. It can be understood that in order to realize the above functions, the IMU calibration device includes hardware structures and / or software modules corresponding to the execution of each function. In combination with the units and algorithm steps of each example described in the embodiment disclosed in this application, the embodiment of the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or computer-driven hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the technical solution of the embodiment of the present application.

[0110] The present application is an embodiment that can divide the functional modules of the IMU calibration device according to the above method example. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one processing unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of units in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation.

[0111] like Figure 6 As shown in FIG. 6 , it is a schematic diagram of the structure of an IMU calibration device provided in an embodiment of the present application. The IMU calibration device 600 can be used to implement the methods described in the above method embodiments. Exemplarily, the IMU calibration device can specifically include: a processing unit 601, a collection unit 602, and a heating unit 603. Among them, the processing unit 601 can be used to perform Figures 1 to 5 The acquisition unit 602 can be used to perform Figures 1 to 5 The heating unit 603 can be used to perform the temperature acquisition function described in any one of the above. Figures 1 to 5 Any one of the above is the function of IMU heating.

[0112] Optional, Figure 6 The IMU calibration device 600 shown may also include a communication unit (not shown in the figure), which is used to support the IMU calibration device 600 to perform the steps of communicating between the IMU calibration device and other devices in the embodiment of the present application. Figure 6 The IMU calibration device 600 shown in the figure may also include a storage unit (not shown in the figure), which stores a program or instruction. When the processing unit 601 executes the program or instruction, Figure 6 The IMU calibration device 600 shown can execute the method described in the above method embodiment.

[0113] Figure 6The technical effects of the IMU calibration device 600 shown can refer to the technical effects described in the above method embodiment, and will not be repeated here. Figure 6 The processing unit 601 involved in the IMU calibration device 600 shown can be implemented by a processor or a processor-related circuit component, which can be a processor or a processing module. The communication unit can be implemented by a transceiver or a transceiver-related circuit component, which can be a transceiver or a transceiver module.

[0114] An embodiment of the present application also provides a computer storage medium, in which computer instructions are stored. When the computer instructions are executed on an IMU calibration device, the IMU calibration device executes the method described in the above method embodiment.

[0115] An embodiment of the present application provides a computer program product, which includes: a computer program or instructions, when the computer program or instructions are executed on a computer, the computer executes the method described in the above method embodiment.

[0116] In addition, an embodiment of the present application also provides a device, which can specifically be a chip, component or module, and the device may include a connected processor and memory; wherein the memory is used to store computer-executable instructions, and when the device is running, the processor can execute the computer-executable instructions stored in the memory so that the device executes the methods in the above-mentioned method embodiments.

[0117] Among them, the IMU calibration device, computer storage medium, computer program product or chip provided in this embodiment are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0118] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which 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. An IMU calibration method, It is characterized in that Applied to a device including an IMU, the method comprises: When the device is in a stationary state, collecting the ambient temperature of the IMU, the IMU is used to measure the angular velocity of the device when it is in motion; Raising the temperature of the IMU from the ambient temperature to a target temperature; Determining an angular velocity offset measured by an IMU having a temperature of the target temperature; The temperature drift of the IMU is calibrated based on the angular velocity offset.

2. The method according to claim 1, It is characterized in that The target temperature is the operating temperature of the IMU when measuring the angular velocity of the device in motion.

3. The method according to claim 1, It is characterized in that The target temperature is the maximum operating temperature when the IMU measures the angular velocity of the device in motion; The determining of the angular velocity offset measured by the IMU whose temperature is the target temperature includes: The determined temperature is an angular velocity offset respectively measured by the IMU at each temperature from the ambient temperature to the target temperature.

4. The method according to any one of claims 1 to 3, It is characterized in that The collecting of the ambient temperature of the IMU includes: The ambient temperature of the IMU is collected by an ambient temperature collection circuit included in the device.

5. The method according to claim 4, It is characterized in that The ambient temperature acquisition circuit comprises a pull-up resistor and a negative temperature coefficient resistor.

6. The method according to any one of claims 1 to 5, It is characterized in that The step of raising the temperature of the IMU from the ambient temperature to the target temperature includes: The temperature of the IMU is increased from the ambient temperature to a target temperature by a heating circuit included in the device.

7. The method according to claim 6, It is characterized in that The heating circuit includes a power driver and a surface mounted power resistor.

8. The method according to any one of claims 1 to 7, It is characterized in that In the process of raising the temperature of the IMU from the ambient temperature to the target temperature, the method further includes: The temperature of the IMU is measured by a temperature sensor within the IMU.

9. The method according to claim 8, It is characterized in that Before measuring the temperature of the IMU by a temperature sensor in the IMU, the method further includes: A temperature sensor within the IMU is calibrated based on the ambient temperature.

10. The method according to any one of claims 1 to 9, It is characterized in that Before collecting the ambient temperature of the IMU, the method further includes: Determine a sudden change in the ambient temperature of the IMU.

11. A chip for IMU calibration, It is characterized in that It includes an MCU, a heating circuit, an ambient temperature acquisition circuit and an IMU, wherein the MCU, the heating circuit, the ambient temperature acquisition circuit and the IMU are connected; The MCU is used to: When the device including the chip is in a stationary state, the ambient temperature of the IMU is collected by the ambient temperature collection circuit, and the IMU is used to measure the angular velocity of the device when it is in motion; Driving the heating circuit to raise the temperature of the IMU from the ambient temperature to a target temperature; Determining an angular velocity offset measured by an IMU having a temperature of the target temperature; The temperature drift of the IMU is calibrated based on the angular velocity offset.

12. The chip according to claim 11, It is characterized in that The target temperature is the operating temperature of the IMU when measuring the angular velocity of the device in motion.

13. The chip according to claim 11, It is characterized in that The target temperature is the maximum operating temperature when the IMU measures the angular velocity of the device in motion; The MCU is specifically used for: The determined temperature is an angular velocity offset respectively measured by the IMU at each temperature from the ambient temperature to the target temperature.

14. The chip according to any one of claims 11 to 13, It is characterized in that The ambient temperature acquisition circuit comprises a pull-up resistor and a negative temperature coefficient resistor.

15. The chip according to any one of claims 11 to 14, It is characterized in that The heating circuit includes a power driver and a surface mounted power resistor.

16. The chip according to any one of claims 11 to 15, It is characterized in that In the process of driving the heating circuit to raise the temperature of the IMU from the ambient temperature to the target temperature, the MCU is also used to measure the temperature of the IMU through a temperature sensor in the IMU.

17. The chip according to claim 16, It is characterized in that Before measuring the temperature of the IMU through the temperature sensor in the IMU, the MCU is also used to calibrate the temperature sensor in the IMU based on the ambient temperature.

18. The chip according to any one of claims 11 to 17, It is characterized in that It also includes a power supply, which is used to power the MCU, the heating circuit, the ambient temperature acquisition circuit and the IMU.

19. An IMU calibration device, It is characterized in that It includes a processor and a memory, the memory is coupled to the processor, the memory is used to store computer program code, the computer program code includes computer instructions, and the processor reads the computer instructions from the memory so that the IMU calibration device executes the method as described in any one of claims 1-10.

20. The device according to claim 19, It is characterized in that It also includes at least one of a heating circuit and an ambient temperature acquisition circuit; The ambient temperature acquisition circuit is used to collect the ambient temperature of the IMU; The heating circuit is used to increase the temperature of the IMU from the ambient temperature to a target temperature.

21. An IMU calibration device, It is characterized in that The method comprises modules for executing each step in the method according to any one of claims 1 to 10.

22. A computer-readable storage medium, It is characterized in that The computer-readable storage medium includes a computer program, and when the computer program is run on the IMU calibration device, the IMU calibration device executes the method as described in any one of claims 1-10.

23. A computer program product, It is characterized in that The computer program product comprises: a computer program or instructions, and when the computer program or instructions are executed on a computer, the computer is caused to perform the method according to any one of claims 1 to 10.

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