A MEMS collision sensor acceleration measurement value calibration method and its application

Abstract

The present invention relates to the technical field of MEMS collision sensors, and in particular to a method for calibrating the acceleration measurement value of a MEMS collision sensor and its application. The method is: when the vehicle is stationary, the MEMS circuit inside the sensor is placed vertically, and the acceleration in the direction of gravity is measured as a1; the MEMS circuit is placed horizontally, and the acceleration in the horizontal direction is measured in the stationary state as a2; the ratio of the actual acceleration of the sensor to the measured acceleration is assumed to be K, and the zero-point error of the sensor is assumed to be A. Since in an ideal stationary state, the acceleration in the horizontal direction measured by the sensor when placed horizontally should be 0, and the acceleration in the direction of gravity measured by the sensor when placed vertically should be 1g, therefore K=1g / (a1-a2), A=a2; assuming that the acceleration value measured by the sensor when the vehicle is in motion is X, then the calibrated acceleration value Y should satisfy the relationship: Y=KX-a2. The method has simple steps, accurate calibration, and is easy to implement.

Description

Technical Field

[0001] The present invention relates to the technical field of MEMS collision sensors, and in particular to a method for calibrating acceleration measurement values ​​of a MEMS collision sensor and an application thereof. Background Art

[0002] MEMS sensors are sensors designed and manufactured using MEMS technology, generally referred to as micromachined microsensors or simply MEMS sensors.

[0003] The automotive industry is one of the main application areas of MEMS sensors. Modern cars need to use a large number of sensors, most of which are MEMS-based devices, such as accelerometers, pressure and inertial sensors, airflow sensors, temperature sensors, fuel sensors, and collision sensors. Among them, MEMS collision sensors are used to detect vehicle acceleration in real time and send the acceleration value to the ECU (electronic controller, generally also called a driving computer in the automotive industry). The acceleration value is processed by the ECU. When it is determined that the vehicle has collided, the safety mechanism is triggered to protect the safety of passengers.

[0004] With the increase of usage time and the influence of temperature and vibration, MEMS collision sensors will age, resulting in a decrease in measurement accuracy. Figure 1 As shown in the figure, L1 is the relationship between the ideal measured acceleration and the vehicle acceleration, and L2 is the relationship between the two after aging. After comparison, it can be seen that the aged MEMS collision sensor has the following problems:

[0005] 1. There is zero point error:

[0006] When the vehicle is stationary, the vehicle acceleration is 0, that is, as shown in L1, in the initial stationary state, the acceleration measured by the MEMS collision sensor should be 0, but it is not 0 in L2;

[0007] 2. The slope K is not 1:

[0008] K represents the measured acceleration of the MEMS collision sensor / actual vehicle acceleration. When the vehicle is running, the measured acceleration of the MEMS collision sensor should always be equal to the actual vehicle acceleration, that is, as shown in L1, K=1, but it is not 1 in L2. Summary of the invention

[0009] In view of the above problems, the present invention provides a method for automatic calibration of a MEMS collision sensor and a MEMS collision sensor constructed based on the method.

[0010] In order to achieve the above technical objectives, a technical solution provided by the present invention is:

[0011] A method for calibrating acceleration measurement values ​​of a MEMS collision sensor, the steps comprising:

[0012] When the vehicle is stationary, the MEMS circuit inside the MEMS collision sensor is placed vertically, and the acceleration in the direction of gravity is measured as a1; then the MEMS circuit is placed horizontally, and in the stationary state, the acceleration in the horizontal direction is measured as a2;

[0013] Assume that the ratio of the actual acceleration of the MEMS collision sensor to the measured acceleration is K, and the zero-point error of the MEMS collision sensor is A. Under ideal conditions, the MEMS collision sensor measures acceleration without error. When the MEMS collision sensor is placed horizontally and stationary, the horizontal acceleration should be measured as 0. When the MEMS collision sensor is placed vertically and stationary, the acceleration in the direction of gravity should be measured as 1g. Therefore, K = 1g / (a1-a2), A = a2;

[0014] Assume that the acceleration value measured by the MEMS collision sensor when the vehicle is in motion is X, then the calibrated acceleration value Y should satisfy the following relationship:

[0015] Y = KX-a2,

[0016] Therefore, based on the measured acceleration value X, a calibrated acceleration value Y can be obtained.

[0017] It can be seen from the above description that the above technical solution has the following advantages:

[0018] The calibration method is simple, highly operable, easy to implement and has high calibration accuracy.

[0019] In order to achieve the above technical objectives, another technical solution provided by the present invention is:

[0020] A MEMS collision sensor based on the above method comprises a MEMS circuit, an ADC unit, an automatic calibration unit and a rotation unit;

[0021] The MEMS circuit is used to measure acceleration value;

[0022] The ADC unit is used to convert the measured acceleration value into a digital signal and output it;

[0023] The automatic calibration unit is used to receive the output signal of the ADC unit, control the output signal of the rotation unit, and output the calibrated acceleration value after processing and analyzing the received signal;

[0024] The rotating unit is used to rotate the MEMS circuit to make it in a horizontal state or a vertical state.

[0025] It can be seen from the above description that the above technical solution has the following advantages:

[0026] The MEMS collision sensor has a simple structure, is easy to implement and has high calibration accuracy.

[0027] The present invention also provides a method for using the above-mentioned MEMS collision sensor, the steps comprising:

[0028] S1, initial power-on, the vehicle where the MEMS collision sensor is located is in a stationary state, and the automatic calibration unit obtains calibration parameters, including:

[0029] The automatic calibration unit sends a rotation signal to the rotation unit. The rotation unit changes the physical position of the MEMS circuit to make it vertical and stationary. The MEMS circuit measures the acceleration and inputs the measured value into the automatic calibration unit after processing by the ADC unit. The value received by the automatic calibration unit is recorded as a1.

[0030] The automatic calibration unit sends a rotation signal to the rotation unit again. The rotation unit changes the physical position of the MEMS circuit to make it horizontal and stationary. The MEMS circuit measures the acceleration and processes the measured value through the ADC unit to input it into the automatic calibration unit. The value received by the automatic calibration unit is recorded as a2.

[0031] The automatic calibration unit calculates the compensation slope K and the zero point error A based on the received values, K=1g / (a1-a2), A=a2;

[0032] S2, the vehicle where the MEMS collision sensor is located starts to move, and the automatic calibration unit outputs the calibrated vehicle acceleration, specifically including:

[0033] The MEMS circuit measures acceleration when the vehicle is in motion and inputs the measured value into the automatic calibration unit after being processed by the ADC unit. The value received by the automatic calibration unit is recorded as X.

[0034] The automatic calibration unit performs calculation processing on the received value and outputs a calibrated acceleration value Y, wherein the calculation method of Y is Y=KX-a2.

[0035] The beneficial effects of the above technical solution are:

[0036] The MEMS collision sensor is simple to use, easy to implement and has high calibration accuracy.

[0037] In order to solve the problem that the existing MEMS collision sensor does not have the data calculation and processing function and cannot perform collision recognition by itself, the present invention is based on the above-mentioned MEMS collision sensor and further provides a MEMS collision sensor with collision recognition function. The specific technical solution is as follows:

[0038] On the basis of the above-mentioned MEMS collision sensor, a collision detection unit is added, and the collision detection unit is used to receive the output signal of the automatic calibration unit, and output a collision signal of the vehicle after analyzing and processing the signal.

[0039] Preferably, the collision detection unit includes an acceleration change rate calculation unit, a change rate judgment unit, an acceleration judgment unit, a time judgment unit and a collision signal generating unit; the acceleration change rate calculation unit receives the output signal of the automatic calibration unit and calculates it, obtains the acceleration change rate signal and outputs it to the change rate judgment unit; the change rate judgment unit receives the acceleration change rate signal and analyzes and judges it, and outputs the change rate judgment signal; the acceleration judgment unit receives the acceleration signal and analyzes and judges it, and outputs the acceleration judgment signal; the time judgment unit receives the acceleration judgment signal and calculates the duration of the acceleration judgment signal, and outputs the time judgment signal; the collision signal generating unit receives the output signal of the change rate judgment unit and / or the output signal of the time judgment unit, determines whether the conditions for generating a collision are met after analyzing the signal, and outputs the judgment result as a collision signal.

[0040] Preferably, the judgment method of the change rate judgment unit is: a threshold is set inside the change rate judgment unit, and the change rate judgment signal output by the change rate judgment unit is recorded as S1. When the signal received by the change rate judgment unit exceeds the set threshold, the change rate judgment signal S1 is output as 1, otherwise S1 is output as 0.

[0041] Preferably, the judgment method of the acceleration judgment unit is: a threshold is set inside the acceleration judgment unit, and the acceleration judgment signal outputted by the acceleration judgment unit is recorded as S2. When the signal received by the acceleration judgment unit exceeds the set threshold, the acceleration judgment signal S2 is output as 1, otherwise S2 is output as 0.

[0042] Preferably, the judgment method of the time judgment unit is as follows: a threshold is set inside the time judgment unit, and the time judgment signal outputted by the time judgment unit is recorded as S3. When the time when the S2 signal received by the time judgment unit is 1 exceeds the set threshold, the time judgment signal S3 is output as 1, otherwise the S3 output is 0.

[0043] Preferably, the judgment method of the collision signal generating unit is: a threshold condition is set inside the collision signal generating unit, and the collision signal outputted by the unit is recorded as S4, and the threshold condition includes the judgment of the change rate judgment signal S1 and / or the judgment of the time judgment signal S3. When the threshold condition is met, the collision signal S4 is output as 1, otherwise the collision signal S4 is output as 0.

[0044] Preferably, the threshold of the change rate judgment unit, the threshold of the acceleration judgment unit, the threshold of the time judgment unit and the threshold conditions of the collision signal generating unit are all set by external ECU input.

[0045] It can be seen from the above description that the above technical solution has the following advantages:

[0046] The MEMS collision sensor has a simple structure and is easy to implement. It can not only perform precise automatic calibration, but also accurately identify collisions, significantly reducing the development cost and performance requirements of vehicle ECUs.

[0047] The present invention also provides a car, comprising any one of the above-mentioned MEMS collision sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic diagram of the error principle of the MEMS collision sensor;

[0049] Figure 2 A schematic diagram of the three-dimensional coordinate system where the MEMS circuit inside the MEMS collision sensor is located;

[0050] Figure 3 This is a schematic diagram of a MEMS collision sensor according to Embodiment 1 of the present invention;

[0051] Figure 4 This is a schematic diagram of a MEMS collision sensor according to Embodiment 1 of the present invention;

[0052] Figure 5 Schematic diagram of a collision detection unit of a MEMS collision sensor in Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0053] Combined with Figure 1-5 The embodiments of the present invention are described in detail, but no limitation is imposed on the claims of the present invention.

[0054] In the prior art, the MEMS circuit inside the MEMS collision sensor is the sensing unit of the MEMS collision sensor, which is based on the principle of piezoelectric effect or capacitive effect and is used to sense the original acceleration physical quantity and convert it into an electrical signal. Then other units of the MEMS collision sensor process and analyze the electrical signal, and finally output a specific value through the output unit of the MEMS collision sensor, which is the acceleration measured by the MEMS collision sensor.

[0055] like Figure 2 As shown in the figure, a three-dimensional coordinate system is established. When the vehicle is moving, when the MEMS circuit inside the MEMS collision sensor is located in the XY plane, only the acceleration in the X-axis direction can be measured, and the gravity acceleration cannot be measured. The output acceleration value in the gravity direction should be 0g. When the MEMS circuit rotates to the YZ plane, the gravity acceleration can be measured, and the output acceleration value should be 1g.

[0056] Based on the above basic principles, a method for calibrating the acceleration measurement value of a MEMS collision sensor is designed, and the steps include:

[0057] When the vehicle is stationary, the MEMS circuit inside the MEMS collision sensor is placed vertically (i.e., in the YZ plane), and the acceleration in the direction of gravity is measured as a1; then the MEMS circuit is rotated 90 degrees to be placed horizontally (i.e., in the XY plane), and in the stationary state, the acceleration in the horizontal direction is measured as a2;

[0058] Assume that the ratio of the actual acceleration of the MEMS collision sensor to the measured acceleration is K, and the zero-point error of the MEMS collision sensor is A. Since the MEMS collision sensor has no error in measuring acceleration in an ideal static state, the acceleration in the horizontal direction should be 0 when placed horizontally, and the acceleration in the direction of gravity should be 1g when placed vertically. Therefore, K = 1g / (a1-a2), A = a2;

[0059] Assume that the acceleration value measured by the MEMS collision sensor when the vehicle is in motion is X, then the calibrated acceleration value Y should satisfy the following relationship:

[0060] Y = KX-a2;

[0061] Therefore, the measured acceleration value X with errors can be substituted into the above formula to obtain the calibrated acceleration value Y.

[0062] It can be seen from the above description that the MEMS collision sensor acceleration measurement value calibration method of the present invention is simple, highly operable, easy to implement and has high calibration accuracy.

[0063] Example 1

[0064] Based on the above calibration method, a MEMS collision sensor is designed, such as Figure 3 As shown, it includes a MEMS circuit, an ADC unit, an automatic calibration unit and a rotation unit;

[0065] MEMS circuits are used to measure acceleration values;

[0066] The ADC unit is used to convert the measured acceleration value into a digital signal and output it;

[0067] The automatic calibration unit is used to receive the output signal of the ADC unit, control the output signal of the rotation unit, and output the calibrated acceleration value after processing and analyzing the received signal;

[0068] The rotating unit is used to rotate the MEMS circuit to make it in a horizontal state or a vertical state.

[0069] In the above solution, the MEMS circuit and the rotating unit can be realized by MEMS technology, and the ADC unit and the automatic calibration unit can be realized by integrated circuit technology.

[0070] The method of using the above-mentioned MEMS collision sensor is as follows:

[0071] S1, initial power-on, the vehicle where the MEMS collision sensor is located is in a stationary state, and the automatic calibration unit obtains calibration parameters, including:

[0072] The automatic calibration unit sends a rotation signal to the rotation unit. The rotation unit changes the physical position of the MEMS circuit to make it vertical and stationary. The MEMS circuit measures the acceleration and inputs the measured value into the automatic calibration unit after processing by the ADC unit. The value received by the automatic calibration unit is recorded as a1.

[0073] The automatic calibration unit sends a rotation signal to the rotation unit again. The rotation unit changes the physical position of the MEMS circuit to make it horizontal and stationary. The MEMS circuit measures the acceleration and processes the measured value through the ADC unit to input it into the automatic calibration unit. The value received by the automatic calibration unit is recorded as a2.

[0074] The automatic calibration unit calculates the compensation slope K and the zero point error A based on the received values, K=1g / (a1-a2), A=a2;

[0075] S2, the vehicle where the MEMS collision sensor is located starts to move, and the automatic calibration unit outputs the calibrated vehicle acceleration, specifically including:

[0076] The MEMS circuit measures acceleration when the vehicle is in motion and inputs the measured value into the automatic calibration unit after being processed by the ADC unit. The value received by the automatic calibration unit is recorded as X.

[0077] The automatic calibration unit performs calculation processing on the received value and outputs a calibrated acceleration value Y, wherein the calculation method of Y is Y=KX-a2.

[0078] It can be seen from the above description that the MEMS collision sensor described in Example 1 has a simple structure, is easy to implement, has high calibration accuracy, and is easy to use.

[0079] When the MEMS collision sensor described in the above scheme is actually designed and applied, a filtering unit can be set between the ADC unit and the automatic calibration unit according to the needs, and the digital signal output by the ADC unit is received by the filtering unit, and the digital signal is denoised, smoothed and enhanced before being input into the automatic calibration unit to further improve the accuracy of the data;

[0080] Example 2

[0081] In addition to the problem of errors caused by aging, the MEMS collision sensors currently on the market also lack data calculation and processing functions and cannot perform collision identification by themselves. After measuring the acceleration value, the data must be sent to the car's ECU for processing. Therefore, developers are required to write ECU programs to set the corresponding data analysis, processing, and judgment logic, so as to identify collision scenarios through the ECU. This places high demands on ECU performance and also increases the development cost of the ECU.

[0082] In order to solve the problem that the existing MEMS collision sensor does not have the data calculation and processing function and cannot perform collision recognition by itself, the present invention is based on the MEMS collision sensor of implementation 1 and further provides a MEMS collision sensor with collision recognition function. The specific technical solution is as follows:

[0083] like Figure 4 As shown, based on the MEMS collision sensor of Example 1, a collision detection unit is added, and the collision detection unit is used to receive the output signal of the automatic calibration unit, and output a collision signal of the vehicle after analyzing and processing the signal.

[0084] like Figure 5 As shown, the collision detection unit may include an acceleration change rate calculation unit, a change rate judgment unit, an acceleration judgment unit, a time judgment unit and a collision signal generation unit, wherein:

[0085] (1) The acceleration change rate calculation unit receives and calculates the output signal of the automatic calibration unit, obtains an acceleration change rate signal, and outputs it to the change rate judgment unit;

[0086] (2) The change rate judgment unit receives the acceleration change rate signal and analyzes and judges it, and outputs a change rate judgment signal. The judgment method is as follows: a threshold value (i.e., threshold condition 1) is set inside the change rate judgment unit, and the change rate judgment signal outputted by the change rate judgment unit is recorded as S1. When the signal received by the change rate judgment unit exceeds the set threshold value, the change rate judgment signal S1 is output as 1, otherwise, the change rate judgment signal S1 is output as 0;

[0087] (3) The acceleration judgment unit receives the acceleration signal, analyzes and judges it, and outputs an acceleration judgment signal; the judgment method is as follows: a threshold value (i.e., threshold condition 2) is set inside the acceleration judgment unit, and the acceleration judgment signal outputted by the acceleration judgment unit is recorded as S2. When the signal received by the acceleration judgment unit exceeds the set threshold value, the acceleration judgment signal S2 is output as 1, otherwise, the acceleration judgment signal S2 is output as 0;

[0088] (4) The time judgment unit receives the acceleration judgment signal and calculates the duration of the acceleration judgment signal, and outputs the time judgment signal. The judgment method is as follows: a threshold value (i.e., threshold condition 3) is set inside the time judgment unit, and the time judgment signal outputted by the time judgment unit is recorded as S3. When the time that the S2 signal received by the time judgment unit is 1 exceeds the set threshold value, the time judgment signal S3 is output as 1, otherwise the S3 is output as 0;

[0089] (5) The collision signal generating unit receives the output signal of the change rate judgment unit and / or the output signal of the time judgment unit, analyzes the signal and determines whether the conditions for generating a collision are met, and outputs the judgment result as a collision signal. The judgment method is as follows: a threshold condition (i.e., threshold condition 4) is set inside the collision signal generating unit, and the collision signal output is recorded as S4. The threshold condition may include a judgment on the change rate judgment signal S1 and / or the time judgment signal S3. When the threshold condition is met, the collision signal S4 is output as 1, otherwise S4 is output as 0.

[0090] The thresholds and threshold conditions in each of the above units can be set by external ECU input or can be pre-built-in.

[0091] Each of the above units can be implemented using the following circuit scheme:

[0092] The acceleration change rate calculation unit is composed of a timer and a subtractor. The timer generates a signal with a period of T to the subtractor. The subtractor subtracts the acceleration value before the current acceleration value from the acceleration value at every time T, and the result is the acceleration change rate.

[0093] The change rate judgment unit is composed of a comparator. If the value of the acceleration change rate is greater than a threshold value, the comparator outputs 1, otherwise it outputs 0.

[0094] The acceleration judgment unit is composed of a comparator. If the acceleration value is greater than a threshold value, the comparator outputs 1, otherwise it outputs 0.

[0095] The time judgment unit is composed of a counter and a comparator. When the S2 signal is 1, the counter counts at a fixed frequency, and the value of the counter represents the duration. When the value of the counter is greater than the threshold condition 3, the comparator outputs 1, otherwise it outputs 0.

[0096] The collision detection unit can be realized by integrated circuit technology.

[0097] From the above description, it can be seen that the MEMS collision sensor described in Example 2 has a simple structure and is easy to implement. The automatic calibration method is simple and can perform accurate automatic calibration. The collision detection unit implementation solution is simple and feasible, low cost, and can accurately identify collisions, which significantly reduces the development cost and performance requirements of the vehicle ECU.

[0098] The MEMS collision sensors described in Examples 1 and 2 of the present application can be widely used in the automotive industry and other applications that require collision sensing. Compared with the MEMS collision sensors in the prior art, the MEMS collision sensors described in the present application are more accurate in measurement and can also reduce the development cost and performance requirements for the vehicle ECU.

[0099] It is understandable that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. For example, the pulse generating end and the vibration motor are not limited to stimulating the greater auricular nerve, but can also stimulate the periphery of the greater auricular nerve and other nerves that can cause sound wave conduction. It should be understood by those skilled in the art that the present invention can still be modified or replaced by equivalents to achieve the same technical effect; as long as the use requirements are met, they are within the protection scope of the present invention.

Claims

1. A MEMS collision sensor, characterized in that: It includes a MEMS circuit, an ADC unit, an automatic calibration unit, a rotation unit, and a collision detection unit; The MEMS circuit is used to measure acceleration value; The ADC unit is used to convert the measured acceleration value into a digital signal and output it; The automatic calibration unit is used to receive the output signal of the ADC unit, control the output signal of the rotation unit, and output the calibrated acceleration value after processing and analyzing the received signal; The rotating unit is used to rotate the MEMS circuit to make it in a horizontal state or a vertical state; The collision detection unit is used to receive the output signal of the automatic calibration unit, and output the collision signal of the vehicle after analyzing and processing the signal; The calibration method of the MEMS collision sensor is: When the vehicle is stationary, the MEMS circuit inside the MEMS collision sensor is placed vertically, and the acceleration in the direction of gravity is measured as a1; then the MEMS circuit is placed horizontally, and in the stationary state, the acceleration in the horizontal direction is measured as a2; Assume that the ratio of the actual acceleration of the MEMS collision sensor to the measured acceleration is K, and the zero-point error of the MEMS collision sensor is A. Under ideal conditions, the MEMS collision sensor measures acceleration without error. When the MEMS collision sensor is placed horizontally and stationary, the acceleration in the horizontal direction should be measured as 0. When the MEMS collision sensor is placed vertically and stationary, the acceleration in the direction of gravity should be measured as 1g. Therefore, K = 1g / (a1-a2), A = a2; Assume that the acceleration value measured by the MEMS collision sensor when the vehicle is in motion is X, then the calibrated acceleration value Y should satisfy the following relationship: Y = KX-a2; Therefore, based on the measured acceleration value X, a calibrated acceleration value Y can be obtained.

2. The MEMS collision sensor according to claim 1, characterized in that: The collision detection unit includes an acceleration change rate calculation unit, a change rate judgment unit, an acceleration judgment unit, a time judgment unit and a collision signal generation unit; The acceleration change rate calculation unit receives the output signal of the automatic calibration unit and calculates it, obtains the acceleration change rate signal and outputs it to the change rate judgment unit; The change rate judgment unit receives the acceleration change rate signal, analyzes and judges it, and outputs a change rate judgment signal; The acceleration judgment unit receives the acceleration signal, analyzes and judges it, and outputs an acceleration judgment signal; The time judgment unit receives the acceleration judgment signal, calculates the duration of the acceleration judgment signal, and outputs the time judgment signal; The collision signal generating unit receives the output signal of the change rate judging unit and / or the output signal of the time judging unit, analyzes the signal and determines whether the condition for generating a collision is met, and outputs the determination result as a collision signal.

3. The MEMS collision sensor according to claim 2, characterized in that: The judgment method of the change rate judgment unit is as follows: a threshold is set inside the change rate judgment unit, and the change rate judgment signal outputted by the change rate judgment unit is recorded as S1. When the signal received by the change rate judgment unit exceeds the set threshold, the change rate judgment signal S1 is output as 1, otherwise S1 is output as 0.

4. The MEMS collision sensor according to claim 3, characterized in that: The acceleration judgment unit has a judgment method as follows: a threshold is set inside the acceleration judgment unit, and the acceleration judgment signal outputted by the acceleration judgment unit is recorded as S2. When the signal received by the acceleration judgment unit exceeds the set threshold, the acceleration judgment signal S2 is output as 1, otherwise S2 is output as 0.

5. The MEMS collision sensor according to claim 4, characterized in that: The judgment method of the time judgment unit is as follows: a threshold is set inside the time judgment unit, and the time judgment signal outputted by the time judgment unit is recorded as S3. When the time when the S2 signal received by the time judgment unit is 1 exceeds the set threshold, the time judgment signal S3 is output as 1, otherwise the S3 output is 0.

6. The MEMS collision sensor according to claim 5, characterized in that: The judgment method of the collision signal generating unit is as follows: a threshold condition is set inside the collision signal generating unit, and the collision signal outputted by the unit is recorded as S4. The threshold condition includes the judgment of the change rate judgment signal S1 and / or the judgment of the time judgment signal S3. When the threshold condition is met, the collision signal S4 is output as 1, otherwise S4 is output as 0.

7. The MEMS collision sensor according to claim 6, characterized in that: The threshold of the change rate judgment unit, the threshold of the acceleration judgment unit, the threshold of the time judgment unit and the threshold conditions of the collision signal generating unit are all set by input from an external ECU.

8. The method for using the MEMS collision sensor according to claim 1, comprising: S1, initial power-on, the vehicle where the MEMS collision sensor is located is in a stationary state, and the automatic calibration unit obtains calibration parameters, including: The automatic calibration unit sends a rotation signal to the rotation unit. The rotation unit changes the physical position of the MEMS circuit to make it vertical and stationary. The MEMS circuit measures the acceleration and inputs the measured value into the automatic calibration unit after processing by the ADC unit. The value received by the automatic calibration unit is recorded as a1. The automatic calibration unit sends a rotation signal to the rotation unit again. The rotation unit changes the physical position of the MEMS circuit to make it horizontal and stationary. The MEMS circuit measures the acceleration and inputs the measured value into the automatic calibration unit after processing by the ADC unit. The value received by the automatic calibration unit is recorded as a2. The automatic calibration unit calculates the ratio K and the zero point error A based on the received values, K=1g / (a1-a2), A=a2; S2, the vehicle where the MEMS collision sensor is located starts to move, and the automatic calibration unit outputs the calibrated vehicle acceleration, specifically including: The MEMS circuit measures acceleration when the vehicle is in motion and inputs the measured value into the automatic calibration unit after being processed by the ADC unit. The value received by the automatic calibration unit is recorded as X. The automatic calibration unit performs calculation processing on the received value and outputs a calibrated acceleration value Y, wherein the calculation method of Y is Y=KX-a2.

9. An automobile comprising the MEMS collision sensor according to any one of claims 1 to 7.

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