CN104748974A - Vehicle collision detection method based on non-horizontal installation of MEMS (Micro Electro Mechanical Systems) sensor - Google Patents

Abstract

The invention discloses a vehicle collision detection method based on the non-horizontal installation of an MEMS (Micro Electro Mechanical Systems) sensor. The method comprises the following steps: S1, installing an MEMS sensor on a vehicle, and calculating an installation attitude angle; S2, decomposing the output of an accelerator of the MEMS into the velocity increment of a vehicle forward direction, a vehicle transverse direction and a vehicle upward direction according to the installation attitude angle; S3, converting the decomposed velocity increment into an acceleration; S4, carrying out collision detection to the vehicle forward direction and/or the transverse direction. According to the detection method provided by the invention, the effective detection on the vehicle collision can be realized.

Description

Based on the vehicle collision detection method of the out-of-level installation of MEMS sensor

Technical field

The present invention relates to a kind of collision checking method, particularly relate to a kind of vehicle collision detection method based on the out-of-level installation of MEMS sensor.

Background technology

Increasing along with vehicle, traffic hazard also more and more takes place frequently, so detect the collision of vehicle timely and effectively, effectively can reduce the injures and deaths of traffic hazard.In order to realize the detection to vehicle collision, general employing OBD mobile unit, this equipment comprises mems accelerometer and gyroscope, but due to the restriction by aspects such as installation site sizes, the installation of this equipment has larger randomness, can not ensure that complete level is installed.

Summary of the invention

In order to solve the problems of the technologies described above, the invention provides a kind of vehicle collision detection method based on the out-of-level installation of MEMS sensor, the effective detection to vehicle collision can be realized.Technical scheme of the present invention is: a kind of vehicle collision detection method based on the out-of-level installation of MEMS sensor, comprises the steps:

S1., MEMS sensor is installed on vehicle, and calculates Installation posture angle;

S2. according to Installation posture angle, the output of the accelerometer of MEMS sensor is decomposed into vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards;

S3. the speed increment after decomposition is converted to acceleration;

S4. collision detection is carried out to vehicle forward direction and/or transverse direction.

Supplementing further as technical scheme, Installation posture angle calculation procedure is as follows:

(1) error of calculation compensates

Make N _a=(N _ax, N _ay, N _az) ^t, then

Wherein Na is the raw velocity increment signal amount output of three axles of accelerometer, N _ax, N _ay, N _azcar working direction, transverse direction and sky speed increment upwards respectively, it is the nominal amount of accelerometer;

(2) the specific force increment δ w after error of calculation compensation ^b:

${\mathrm{\δw}}^b=\mathrm{Ea}({\mathrm{\δw}}_1^b-k_0\mathrm{\δT})$

δ T is the systematic sampling time interval, k ₀be zero of each axle of accelerometer partially, Ea is the alignment error matrix of accelerometer;

(3) specific force incremental integration is calculated

Δw ^b _＝Σδw ^b

(4) normalization

$\mathrm{\Δw}=\sqrt{\mathrm{\Δ}{w}_x^{b^2}+\mathrm{\Δ}{w}_y^{b^2}+\mathrm{\Δ}{w}_z^{b^2}}$

$g_{\mathrm{\α}}^b=\frac{\mathrm{\Δ}{w}_{\mathrm{\α}}^b}{\mathrm{\Δw}}$

Wherein, g _α(α=x, y, z) is car working direction, transverse direction and sky upwards normalized result, and Δ w is that intermediate variable exports;

(5) Installation posture angle is calculated

Order: roll angle then in Installation posture angle and the angle of pitch are calculated as follows: θ=arcsinT ₃₂; wherein: θ is roll angle, γ is the angle of pitch.

Supplementing further as technical scheme, the output quantity decomposition method of degree of will speed up meter is vehicle forward direction, the method for lateral direction of car and vehicle sky speed increment is upwards: use the output quantity of following formula to accelerometer to decompose, obtain the speed increment in three directions;

${\left|\begin{array}{c}g\_\mathrm{level}\_x\\ g\_\mathrm{level}\_y\\ g\_\mathrm{level}\_z\end{array}\right|}^T={\left|\begin{array}{c}\mathrm{wb}\_x\\ \mathrm{wb}\_y\\ \mathrm{wb}\_z\end{array}\right|}^T*\left|\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\γ}& \sin \mathrm{\γ}\\ 0& -\sin \mathrm{\γ}& \cos \mathrm{\γ}\end{array}\right|*\left|\begin{array}{ccc}\cos \mathrm{\θ}& 0& -\sin \mathrm{\θ}\\ 0& 1& 0\\ \sin \mathrm{\θ}& 0& \cos \mathrm{\θ}\end{array}\right|$

Wherein, g_level_x, g_level_y, g_level_z is at vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards after decomposing, wb_x, wb_y, wb_z compensate specific force increment in vehicle forward direction, lateral direction of car and the decomposition upwards of vehicle sky.

Supplementing further as technical scheme, by the method that the speed increment after decomposition is converted to acceleration is: use following formula that speed increment is converted to acceleration;

g_x＝g_level_x/δT/g ₀；

g_y＝g_level_y/δT/g ₀；

Wherein, g ₀be local gravitational acceleration, g_x and g_y represents the acceleration of vehicle forward direction and lateral direction of car respectively, and unit is: g.

Supplementing further as technical scheme, the method of vehicle forward direction collision detection is: often get ten groups of accekerations and calculate a variance, and add round-robin queue, until last group of the variance ratio finding that there is one group of accekeration and latter one group when being all greater than a certain multiple, be judged to there occurs collision in vehicle forward direction.

Supplementing further as technical scheme, the method of lateral direction of car collision detection is: often get ten groups of accekerations and calculate a variance, and add round-robin queue, until last group of the variance ratio finding that there is one group of accekeration and latter one group when being all greater than a certain multiple, be judged to there occurs collision in the lateral direction of the vehicle.

The invention still further relates to a kind of collision detecting apparatus for vehicle based on the out-of-level installation of MEMS sensor, comprising:

Sensor is installed and Installation posture angle calculation element, for installing MEMS sensor in vehicle, and calculates Installation posture angle;

The output decomposer of accelerometer, for being decomposed into vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards according to Installation posture angle by the output of the accelerometer of MEMS sensor;

Acceleration conversion equipment, for being converted to acceleration by the speed increment after decomposition;

Collision detecting device, for carrying out collision detection to vehicle forward direction and/or transverse direction.

Beneficial effect: invent herein under the prerequisite of the out-of-level installation of MEMS, by calculating out-of-level degree (Installation posture angle) and carrying out the method for coordinate conversion, become vehicle forward direction, transverse direction, sky to three-dimensional system of coordinate MEMS ordinate transform, by detecting vehicle forward direction in real time, transverse acceleration changes the detection realized vehicle collision.The present invention can identify car two collision fast and effectively, and according to the adjustment for the variance difference multiple compared, present invention achieves the vehicle collision identifying different sensitivity.

Accompanying drawing explanation

Fig. 1 is schematic flow sheet of the present invention.

Embodiment

Embodiment:

Based on a vehicle collision detection method for the out-of-level installation of MEMS sensor, comprise the steps:

S1., MEMS sensor is installed on vehicle, and calculates Installation posture angle;

Installation posture angle calculation procedure is as follows:

(1) error of calculation compensates

Make N _a=(N _ax, N _ay, N _az) ^t, then

Wherein Na is the raw velocity increment signal amount output of three axles of accelerometer, N _ax, N _ay, N _azcar working direction, transverse direction and sky speed increment upwards respectively, it is the nominal amount of accelerometer;

(2) the specific force increment δ w after error of calculation compensation ^b:

${\mathrm{\δw}}^b=\mathrm{Ea}({\mathrm{\δw}}_1^b-k_0\mathrm{\δT})$

δ T is the systematic sampling time interval, k ₀be zero of each axle of accelerometer partially, Ea is the alignment error matrix of accelerometer;

(3) specific force incremental integration is calculated

Δw ^b＝Σδw ^b

(4) normalization

$\mathrm{\Δw}=\sqrt{\mathrm{\Δ}{w}_x^{b^2}+\mathrm{\Δ}{w}_y^{b^2}+\mathrm{\Δ}{w}_z^{b^2}}$

$g_{\mathrm{\α}}^b=\frac{\mathrm{\Δ}{w}_{\mathrm{\α}}^b}{\mathrm{\Δw}}$

Wherein, g _α(α=x, y, z) is car working direction, transverse direction and sky upwards normalized result, and Δ w is that intermediate variable exports;

(5) Installation posture angle is calculated

Order: roll angle then in Installation posture angle and the angle of pitch are calculated as follows: θ=arcsinT ₃₂; wherein: θ is roll angle, γ is the angle of pitch.

S2. according to Installation posture angle, the output of the accelerometer of MEMS sensor is decomposed into vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards;

The output quantity decomposition method of degree of will speed up meter is vehicle forward direction, the method for lateral direction of car and vehicle sky speed increment is upwards: use the output quantity of following formula to accelerometer to decompose, obtain the speed increment in three directions;

${\left|\begin{array}{c}g\_\mathrm{level}\_x\\ g\_\mathrm{level}\_y\\ g\_\mathrm{level}\_z\end{array}\right|}^T={\left|\begin{array}{c}\mathrm{wb}\_x\\ \mathrm{wb}\_y\\ \mathrm{wb}\_z\end{array}\right|}^T*\left|\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\γ}& \sin \mathrm{\γ}\\ 0& -\sin \mathrm{\γ}& \cos \mathrm{\γ}\end{array}\right|*\left|\begin{array}{ccc}\cos \mathrm{\θ}& 0& -\sin \mathrm{\θ}\\ 0& 1& 0\\ \sin \mathrm{\θ}& 0& \cos \mathrm{\θ}\end{array}\right|$

Wherein, g_level_x, g_level_y, g_level_z is at vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards after decomposing, wb_x, wb_y, wb_z compensate specific force increment in vehicle forward direction, lateral direction of car and the decomposition upwards of vehicle sky.

S3. the speed increment after decomposition is converted to acceleration;

By the method that the speed increment after decomposition is converted to acceleration be: use following formula that speed increment is converted to acceleration;

g_x＝g_level_x/δT/g ₀；

g_y＝g_level_y/δT/g ₀；

Wherein, g ₀be local gravitational acceleration, g_x and g_y represents the acceleration of vehicle forward direction and lateral direction of car respectively, and unit is: g.

S4. collision detection is carried out to vehicle forward direction and/or transverse direction;

The method of vehicle forward direction collision detection is: often get ten groups of accekerations and calculate a variance, and add round-robin queue, until last group of the variance ratio finding that there is one group of accekeration and latter one group when being all greater than a certain multiple, be judged to there occurs collision in vehicle forward direction, as follows:

varx1>factor*varx2；

varx1>factor*varx0；

The method of lateral direction of car collision detection is: often get ten groups of accekerations and calculate a variance, and add round-robin queue, until last group of the variance ratio finding that there is one group of accekeration and latter one group when being all greater than a certain multiple, be judged to there occurs collision in the lateral direction of the vehicle, as follows:

vary1>factor*vary2；

vary1>factor*vary0；

Wherein, vary0, vary1, vary2 represent the variance yields of three groups of adjacent acceleration, and factor is adjustable coefficient, and the less collision recognition of coefficient is sensitiveer, can regulate the size of this coefficient according to actual conditions.

The invention still further relates to a kind of collision detecting apparatus for vehicle based on the out-of-level installation of MEMS sensor, comprising:

Sensor is installed and Installation posture angle calculation element, for installing MEMS sensor in vehicle, and calculates Installation posture angle;

The output decomposer of accelerometer, for being decomposed into vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards according to Installation posture angle by the output of the accelerometer of MEMS sensor;

Acceleration conversion equipment, for being converted to acceleration by the speed increment after decomposition;

Collision detecting device, for carrying out collision detection to vehicle forward direction and/or transverse direction.

Claims (11)

1., based on a vehicle collision detection method for the out-of-level installation of MEMS sensor, it is characterized in that: comprise the steps:

S1., MEMS sensor is installed on vehicle, and calculates Installation posture angle;

S2. according to Installation posture angle, the output of the accelerometer of MEMS sensor is decomposed into vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards;

S3. the speed increment after decomposition is converted to acceleration;

S4. collision detection is carried out to vehicle forward direction and/or transverse direction.

2., as claimed in claim 1 based on the vehicle collision detection method of the out-of-level installation of MEMS sensor, it is characterized in that: Installation posture angle calculation procedure is as follows:

(1) error of calculation compensates

Make N _a=(N _ax, N _ay, N _az) ^t, then

Wherein Na is the raw velocity increment signal amount output of three axles of accelerometer, N _ax, N _ay, N _azcar working direction, transverse direction and sky speed increment upwards respectively, it is the nominal amount of accelerometer;

(2) the specific force increment δ w after error of calculation compensation ^b:

δ T is the systematic sampling time interval, k ₀be zero of each axle of accelerometer partially, Ea is the alignment error matrix of accelerometer;

(3) specific force incremental integration is calculated

Δw ^b＝Σδw ^b

(4) normalization

Wherein, g _α(α=x, y, z) is car working direction, transverse direction and sky upwards normalized result, and Δ w is that intermediate variable exports;

(5) Installation posture angle is calculated

Order: roll angle then in Installation posture angle and the angle of pitch are calculated as follows: θ=arcsin T ₃₂; wherein: θ is roll angle, γ is the angle of pitch.

3. as claimed in claim 2 based on the vehicle collision detection method of the out-of-level installation of MEMS sensor, it is characterized in that, the output quantity decomposition method of degree of will speed up meter is vehicle forward direction, the method for lateral direction of car and vehicle sky speed increment is upwards: use the output quantity of following formula to accelerometer to decompose, obtain the speed increment in three directions;

Wherein, g_level_x, g_level_y, g_level_z is at vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards after decomposing, wb_x, wb_y, wb_z are that compensation specific force increment in claim 2 is in vehicle forward direction, lateral direction of car and the decomposition upwards of vehicle sky.

4. as claimed in claim 3 based on the vehicle collision detection method of the out-of-level installation of MEMS sensor, it is characterized in that, by the method that the speed increment after decomposition is converted to acceleration be: use following formula that speed increment is converted to acceleration;

g_x＝g_level_x/δT/g ₀；

g_y＝g_level_y/δT/g ₀；

Wherein, g ₀be local gravitational acceleration, g_x and g_y represents the acceleration of vehicle forward direction and lateral direction of car respectively, and unit is: g.

5. as claimed in claim 4 based on the vehicle collision detection method of the out-of-level installation of MEMS sensor, it is characterized in that, the method of vehicle forward direction collision detection is: often get ten groups of accekerations and calculate a variance, and add round-robin queue, until last group of the variance ratio finding that there is one group of accekeration and latter one group when being all greater than a certain multiple, be judged to there occurs collision in vehicle forward direction.

6. as claimed in claim 5 based on the vehicle collision detection method of the out-of-level installation of MEMS sensor, it is characterized in that, the method of lateral direction of car collision detection is: often get ten groups of accekerations and calculate a variance, and add round-robin queue, until last group of the variance ratio finding that there is one group of accekeration and latter one group when being all greater than a certain multiple, be judged to there occurs collision in the lateral direction of the vehicle.

7. based on a collision detecting apparatus for vehicle for the out-of-level installation of MEMS sensor, it is characterized in that: comprising:

Sensor is installed and Installation posture angle calculation element, for installing MEMS sensor in vehicle, and calculates Installation posture angle;

The output decomposer of accelerometer, for being decomposed into vehicle forward direction, lateral direction of car and vehicle sky speed increment upwards according to Installation posture angle by the output of the accelerometer of MEMS sensor;

Acceleration conversion equipment, for being converted to acceleration by the speed increment after decomposition;

Collision detecting device, for carrying out collision detection to vehicle forward direction and/or transverse direction.