MEMS accelerometer temperature compensation method and system, medium, equipment and product

Abstract

The invention discloses an MEMS accelerometer temperature compensation method and system, a medium, equipment and a product in the technical field of MEMS accelerometer temperature compensation, and aims to solve the problem of poor compensation effect in the prior art. The method comprises the following steps: establishing a temperature compensation model of the MEMS accelerometer, and initializing a temperature compensation coefficient of the temperature compensation model; dynamically updating a temperature compensation coefficient of the temperature compensation model based on an RLS algorithm to obtain an updated temperature compensation model; and performing temperature compensation on the MEMS accelerometer by using the updated temperature compensation model to obtain an acceleration after temperature compensation. Real-time temperature sensor data and compensation parameters can be combined, temperature change, aging effect and environmental interference can be adapted in real time, the scale factor and zero offset long-term stability of the MEMS accelerometer are improved, the compensation precision is improved, and the MEMS accelerometer has the advantages of being easy to implement and simple in structure.

Description

Technical Field

[0001] The present invention relates to the technical field of MEMS accelerometer temperature compensation, and particularly relates to a method, system, medium, device and product for MEMS accelerometer temperature compensation. Background Art

[0002] MEMS (Microelectro Mechanical Systems) accelerometers are widely used in consumer electronics, automobiles, industrial control, medical devices, aerospace and other fields due to their advantages of miniaturization, low power consumption, low cost, etc., and are the core components of sensors in system applications. The scale factor (SF) of a MEMS accelerometer represents the proportional relationship between the output signal (such as voltage, digital value) and the actual acceleration input, and the bias (B) represents the actual output value when the input signal is 0, which are key indicators affecting the measurement accuracy of the sensor. Temperature changes cause changes in the stiffness and damping coefficient of the mechanical structure of the sensor (such as cantilever beams, mass blocks), and thus the scale factor and bias of the MEMS accelerometer drift with temperature changes, which has a greater impact on the accuracy of system applications. Therefore, it is necessary to perform temperature compensation on the MEMS accelerometer to improve the accuracy and performance of the sensor and the system.

[0003] Currently, methods such as polynomial fitting and look-up table interpolation are used for MEMS accelerometer temperature compensation. Most of the compensation models of polynomial fitting use first-order or second-order polynomials to fit the relationship between the scale factor, bias and temperature. However, there are high-order non-linearities in actual temperature changes (such as material hysteresis effects, sudden changes in packaging stress), resulting in an increase in fitting residuals. At the same time, there is uneven temperature distribution inside the sensor chip (such as the temperature difference between ASIC and MEMS structures), and the polynomial model assumes uniform temperature, resulting in local errors; the look-up table interpolation method relies on calibration data at finite temperature points, there is an interval between temperature sampling points, and linear interpolation will introduce errors, resulting in poor compensation effects. Summary of the Invention

[0004] The purpose of the present invention is to overcome the limitations of MEMS accelerometer temperature compensation in the prior art, and provide a method, system, medium, device and product for MEMS accelerometer temperature compensation, which can combine real-time temperature sensor data with compensation parameters, adapt to temperature changes, aging effects and environmental interference in real time, improve the long-term stability of the scale factor and bias of the MEMS accelerometer, not only improve the compensation accuracy, but also has the characteristics of easy implementation and simple structure.

[0005] To solve the above technical problems, the present invention is implemented by the following technical solutions:

[0006] In a first aspect, the present invention provides a method for MEMS accelerometer temperature compensation, including:

[0007] Establish a temperature compensation model for the MEMS accelerometer and initialize the temperature compensation coefficients of the temperature compensation model;

[0008] Dynamically update the temperature compensation coefficients of the temperature compensation model based on the RLS algorithm to obtain an updated temperature compensation model;

[0009] Use the updated temperature compensation model to perform temperature compensation on the MEMS accelerometer to obtain the temperature-compensated acceleration.

[0010] Optionally, the expression of the temperature compensation model is as follows:

[0011]

[0012] Where, represents the output acceleration of the MEMS accelerometer, represents the true acceleration, represents the scale factor of the MEMS accelerometer, represents the zero bias of the MEMS accelerometer, , represents the scale factor of the MEMS accelerometer at temperature , , represents the zero bias of the MEMS accelerometer at temperature , , , , represent compensation parameters, represents noise.

[0013] Optionally, the compensation parameters for initializing the temperature compensation model include:

[0014] Fix the MEMS accelerometer on a dividing table with a temperature chamber, select measured temperature points to obtain a set of temperature points ; where, , represents the th measured temperature point;

[0015] After the MEMS accelerometer is kept at each temperature point for a set time, perform scale factor and zero bias tests on the MEMS accelerometer to obtain scale factors and zero biases ; where, , represents the th scale factor, , represents the th zero bias;

[0016] Using the least squares method, for the scale factor and zero bias perform a first-order curve fitting to obtain the initial temperature compensation coefficient , where , , , , represent compensation parameters, represents transpose.

[0017] Optionally, the temperature compensation coefficient of the temperature compensation model updated based on the RLS algorithm includes:

[0018] Initialize the covariance matrix ;

[0019] For each moment , perform the following steps:

[0020] Collect the output acceleration , true acceleration and temperature of the MEMS accelerometer at moment

[0021] According to the output acceleration , true acceleration and temperature , construct the input vector ; where , represents transpose;

[0022] According to the output acceleration , input vector and the temperature compensation coefficient at moment , calculate the prediction error

[0023] According to the input vector and the covariance matrix at moment , calculate the gain vector

[0024] According to the prediction error and gain vector , update the temperature compensation coefficient and covariance matrix at moment

[0025] Optionally, the prediction error Obtained by the following formula:

[0026] ,

[0027] wherein, denotes the transpose of;

[0028] The gain vector is obtained by the following formula:

[0029] ,

[0030] wherein, denotes the forgetting factor;

[0031] The temperature compensation coefficient at time is obtained by the following formula:

[0032] ,

[0033] The covariance matrix at time is obtained by the following formula:

[0034] .

[0035] Optionally, the temperature-compensated acceleration is obtained by the following formula:

[0036]

[0037] wherein, denotes the acceleration after temperature compensation at time denotes the output acceleration of the MEMS accelerometer at time denotes the true acceleration at time denotes the scale factor at temperature ; denotes the zero offset at temperature ; , , , denotes the compensation parameter at time

[0038] In a second aspect, the present invention provides a MEMS accelerometer temperature compensation system, including a MEMS accelerometer, a control circuit, and a power supply module;

[0039] The control circuit includes a microprocessor, which communicates with the MEMS accelerometer by establishing an SPI master-slave relationship and performs temperature compensation on the data collected by the MEMS accelerometer;

[0040] The power supply module is used to supply power to the MEMS accelerometer and the control circuit;

[0041] The temperature compensation for the data collected by the MEMS accelerometer includes:

[0042] Establish a temperature compensation model for the MEMS accelerometer and initialize the temperature compensation coefficient of the temperature compensation model;

[0043] Dynamically update the temperature compensation coefficient of the temperature compensation model based on the RLS algorithm to obtain an updated temperature compensation model;

[0044] Use the updated temperature compensation model to perform temperature compensation on the MEMS accelerometer to obtain the temperature-compensated acceleration.

[0045] In a third aspect, the present invention provides a computer-readable storage medium, on which computer instructions are stored. When the computer instructions are executed by a processor, the steps of the MEMS accelerometer temperature compensation method described in any one of the first aspects are implemented.

[0046] In a fourth aspect, the present invention provides a computer device, including:

[0047] A memory for storing computer instructions;

[0048] A processor for executing the computer instructions to implement the steps of the MEMS accelerometer temperature compensation method described in any one of the first aspects.

[0049] In a fifth aspect, the present invention provides a computer program product, including computer instructions, characterized in that when the computer instructions are executed by a processor, the steps of the MEMS accelerometer temperature compensation method described in any one of the first aspects are implemented.

[0050] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0051] 1. The MEMS accelerometer temperature compensation method provided by the present invention can combine real-time temperature sensor data with compensation parameters, adapt to temperature changes, aging effects, and environmental interference in real time, and improve the long-term stability of the scale factor and zero offset of the MEMS accelerometer by establishing a temperature compensation model for the MEMS accelerometer and dynamically updating the temperature compensation coefficient of the temperature compensation model using the RLS algorithm;

[0052] 2. The MEMS accelerometer temperature compensation system provided by the present invention realizes the temperature compensation of the MEMS accelerometer by setting a MEMS accelerometer, a control circuit, and a power supply module. It not only improves the compensation accuracy, but also has the characteristics of being easy to implement and having a simple structure, which has practical significance and good application prospects.

[0053] 3. The computer-readable storage medium, device, and product provided by the present invention can execute the steps of the MEMS accelerometer temperature compensation method provided by the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 FIG. is a flowchart of the MEMS accelerometer temperature compensation method according to an embodiment of the present invention;

[0055] Figure 2 FIG. is an effect diagram of the scale factor temperature compensation of the MEMS accelerometer according to an embodiment of the present invention;

[0056] Figure 3 FIG. is an effect diagram of the zero bias temperature compensation of the MEMS accelerometer according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present invention and the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. Without conflict, the technical features in the embodiments of the present invention and the embodiments can be combined with each other.

[0058] It should be noted that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0059] Embodiment 1:

[0060] An embodiment of the present invention discloses a MEMS accelerometer temperature compensation method. Referring to Figure 1 as shown, the specific steps are as follows:

[0061] S1, establish a temperature compensation model of the MEMS accelerometer and initialize the temperature compensation coefficient of the temperature compensation model;

[0062] S2, dynamically update the temperature compensation coefficient of the temperature compensation model based on the RLS algorithm to obtain an updated temperature compensation model;

[0063] S3, performing temperature compensation on the MEMS accelerometer using the updated temperature compensation model to obtain a temperature compensated acceleration.

[0064] Specifically, in step S1, the expression of the temperature compensation model is as follows:

[0065]

[0066] in, is the raw acceleration, i.e. the output acceleration of the MEMS accelerometer, represents the true acceleration, i.e. the reference datum, represents noise, and is the expression of the scale factor and zero bias changing with temperature. Assuming that the change with temperature is linear, it is expressed as follows:

[0067] ,

[0068] in, Indicates the temperature The scale factor of the MEMS accelerometer is Indicates the temperature The zero bias of the MEMS accelerometer is , , , Represents the compensation parameter, combined into the temperature compensation coefficient, expressed as , Indicates transpose.

[0069] The initial temperature compensation coefficient of the MEMS accelerometer is obtained by testing the indexing table with a temperature chamber. First, fix the MEMS accelerometer on the indexing table with a temperature chamber, and select Temperature points to be measured After keeping warm for 1 hour at each temperature point, the accelerometer is tested for scale factor and zero bias, which can be obtained Scaling Factor and zero bias , using the least squares method, the scale factor and zero bias are fitted with a first-order curve to obtain the initial temperature compensation coefficient .

[0070] In step S2, the parameters to be initialized in the RLS algorithm include the forgetting factor and the initial covariance matrix , forgetting factor The value is between 0.95 and 0.99; the initial covariance matrix Initialize to 50~100 times the identity matrix.

[0071] The RLS algorithm is a process of online recursive update. For each moment , the calculation process is as follows:

[0072] (1) Obtain data: Collect the output acceleration of the MEMS accelerometer at moment , the true acceleration and the temperature ;

[0073] (2) Construct the input vector: According to the output acceleration , the true acceleration and the temperature , construct the input vector ; where ;

[0074] (3) Calculate the prediction error: According to the output acceleration , the input vector and the temperature compensation coefficient at moment , calculate the prediction error : , where represents the transpose of ;

[0075] (4) Calculate the gain vector: According to the input vector and the covariance matrix at moment , calculate the gain vector : , where represents the forgetting factor;

[0076] (5) Update the parameter estimation: According to the prediction error and the gain vector , update the temperature compensation coefficient at moment : ;

[0077] (6) Update the covariance matrix: According to the prediction error and the gain vector , update the covariance matrix at moment : .

[0078] In step S3, after dynamically updating the temperature compensation coefficient , use the new compensation parameter to perform temperature compensation on the MEMS to obtain the compensated result, and the calculation is as follows:

[0079]

[0080] Among them, represents the acceleration after temperature compensation at time represents the output acceleration of the MEMS accelerometer at time represents the true acceleration at time represents the scale factor at temperature represents the zero offset at temperature , , , represents the compensation parameter at time

[0081] In this embodiment, the temperature compensation method for the MEMS accelerometer based on RLS dynamic update is experimentally verified. The test is carried out in a dividing table with a temperature chamber. The selected test temperature points are -45°C, -30°C, -20°C, -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C. At each temperature point, the scale factor and zero offset of the MEMS accelerometer are tested. The comparison of the outputs before and after the scale factor and zero offset compensation is as Figure 2 and Figure 3 shown. The red curve is the curve after temperature compensation, and the blue curve with stars is the curve before temperature compensation. The temperature compensation effect is obvious.

[0082] According to the compensation comparison chart, in the temperature change range of -45°C to 60°C for the MEMS accelerometer system, the scale factor before full-temperature change compensation is 1685 LSB / g, and after compensation is 257 LSB / g. The zero offset before full-temperature change compensation is 327 mg, and after compensation is 19 mg. By comparing the test results of the scale factor and zero offset before and after temperature compensation, it can be seen that the error after compensation becomes significantly smaller. This method achieves the temperature compensation effect of the MEMS accelerometer.

[0083] Embodiment 2:

[0084] Based on the same inventive concept as Embodiment 1, this embodiment of the present invention discloses a MEMS accelerometer temperature compensation system, including a MEMS accelerometer, a control circuit, and a power supply module.

[0085] The control circuit includes a microprocessor; the microprocessor is mainly responsible for establishing an SPI master-slave relationship with the MEMS accelerometer for communication, performing temperature compensation on the data collected by the MEMS accelerometer, and then sending it to the host computer; the microprocessor also needs to respond to the host computer instructions to perform parameter upload and coefficient configuration. ​​

[0086] The power supply module filters the externally input DC power supply and then supplies it to the linear voltage regulator to convert it into the working voltages required by each sub-block of the system. At the same time, an analog and digital separation design is carried out for the system power supply.

[0087] The temperature compensation for the data collected by the MEMS accelerometer includes:

[0088] Establish a temperature compensation model for the MEMS accelerometer and initialize the temperature compensation coefficient of the temperature compensation model;

[0089] Dynamically update the temperature compensation coefficient of the temperature compensation model based on the RLS algorithm to obtain an updated temperature compensation model;

[0090] Use the updated temperature compensation model to perform temperature compensation on the MEMS accelerometer to obtain the temperature-compensated acceleration.

[0091] For the specific function implementation of each of the above modules, refer to the relevant content in the method of Embodiment 1, which will not be elaborated here.

[0092] Embodiment 3:

[0093] This embodiment provides a computer-readable storage medium, on which computer instructions are stored. When the computer instructions are executed by a processor, the steps of the MEMS accelerometer temperature compensation method described in any one of Embodiment 1 are implemented.

[0094] Embodiment 4:

[0095] This embodiment provides a computer device, including:

[0096] A memory for storing computer instructions;

[0097] A processor for executing the computer instructions to implement the steps of the MEMS accelerometer temperature compensation method described in any one of Embodiment 1.

[0098] Embodiment 5:

[0099] This embodiment provides a computer program product, including computer instructions, characterized in that when the computer instructions are executed by a processor, the steps of the MEMS accelerometer temperature compensation method described in any one of Embodiment 1 are implemented.

[0100] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0101] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a system for realizing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0102] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction system that realizes the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0103] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, so that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable devices provide steps for realizing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0104] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit and scope of the present invention as protected by the claims. All of these are within the protection scope of the present invention.

Claims

1. A temperature compensation method for a MEMS accelerometer, characterized in that, including: establishing a temperature compensation model for the MEMS accelerometer and initializing the temperature compensation coefficients of the temperature compensation model; dynamically updating the temperature compensation coefficients of the temperature compensation model based on the RLS algorithm to obtain an updated temperature compensation model; performing temperature compensation on the MEMS accelerometer using the updated temperature compensation model to obtain temperature-compensated acceleration.

2. The temperature compensation method of the MEMS accelerometer according to claim 1, characterized in that The expression of the temperature compensation model is as follows: Among them, represents the output acceleration of the MEMS accelerometer, represents the true acceleration, represents the scale factor of the MEMS accelerometer, represents the zero bias of the MEMS accelerometer, , represents that the temperature is when the scale factor of the MEMS accelerometer, , represents that the temperature is when the zero bias of the MEMS accelerometer, , , , represent compensation parameters, represents noise.

3. The temperature compensation method of the MEMS accelerometer according to claim 1, wherein The compensation parameters for initializing the temperature compensation model include: Fix the MEMS accelerometer on the indexing table with a temperature chamber, and select temperature points to be measured to obtain a set of temperature points ; among them, , represents the th temperature point to be measured; After keeping the MEMS accelerometer at each temperature point for a set time, perform scale factor and zero offset tests on the MEMS accelerometer to obtain scale factors and zero offsets ; where , represents the th scale factor, , represents the th zero offset; Using the least squares method, for the scale factor and the zero offset perform a first-order curve fitting to obtain the initial temperature compensation coefficient , where , , , , represent compensation parameters, represents the transpose.

4. The temperature compensation method of the MEMS accelerometer according to claim 1, characterized in that, The dynamic update of the temperature compensation coefficients of the temperature compensation model based on the RLS algorithm includes: Initialize the covariance matrix ; For each moment , perform the following steps: Acquisition Output acceleration of the MEMS accelerometer at a certain moment , True acceleration and temperature ; According to the output acceleration , true acceleration and temperature , construct an input vector ; where , denotes transpose; According to the output acceleration , input vector and the temperature compensation coefficient at a moment , calculate the prediction error ; According to the input vector and the covariance matrix at a moment , calculate the gain vector ; According to the prediction error and the gain vector , update the temperature compensation coefficient and the covariance matrix .

5. The MEMS accelerometer temperature compensation method according to claim 4, wherein The prediction error is obtained by the following formula: ， Among them, denotes transpose of; The gain vector is obtained by the following formula: ， Among them, represents the forgetting factor; The temperature compensation coefficient at a moment is obtained by the following formula: ， The covariance matrix at a moment is obtained by the following formula: 。 6. The temperature compensation method of the MEMS accelerometer according to claim 1, wherein The temperature-compensated acceleration is obtained through the following formula: Among them, represents the acceleration after temperature compensation at time represents the output acceleration of the MEMS accelerometer at time represents the true acceleration at time represents the scale factor at temperature represents the zero offset at temperature , , , represent the compensation parameters at time​​ 7. A temperature compensation system for a MEMS accelerometer, characterized in that, including a MEMS accelerometer, a control circuit, and a power supply module; The control circuit includes a microprocessor, which communicates with the MEMS accelerometer by establishing an SPI master-slave relationship and performs temperature compensation on the data collected by the MEMS accelerometer; The power supply module is used to supply power to the MEMS accelerometer and the control circuit; The temperature compensation of the data collected by the MEMS accelerometer includes: establishing a temperature compensation model for the MEMS accelerometer and initializing the temperature compensation coefficients of the temperature compensation model; dynamically updating the temperature compensation coefficients of the temperature compensation model based on the RLS algorithm to obtain an updated temperature compensation model; performing temperature compensation on the MEMS accelerometer using the updated temperature compensation model to obtain temperature-compensated acceleration.

8. A computer-readable storage medium having computer instructions stored thereon, characterized in that, When the computer instruction is executed by a processor, the steps of the MEMS accelerometer temperature compensation method described in any one of claims 1-6 are implemented.

9. A computer device, characterized in that, including: a memory for storing computer instructions; a processor for executing the computer instructions to implement the steps of the MEMS accelerometer temperature compensation method described in any one of claims 1-6.

10. A computer program product, comprising computer instructions, characterized in that, When the computer instruction is executed by a processor, the steps of the MEMS accelerometer temperature compensation method described in any one of claims 1-6 are implemented.

Images