KR20120062390A

KR20120062390A - Inertial sensor

Info

Publication number: KR20120062390A
Application number: KR1020100123628A
Authority: KR
Inventors: 김종운; 정원규
Original assignee: 삼성전기주식회사
Priority date: 2010-12-06
Filing date: 2010-12-06
Publication date: 2012-06-14

Abstract

The present invention relates to an inertial sensor, the inertial sensor according to the present invention is provided with a drive means, a detection means, an error detection means and a drive control means 100 on one surface, the center is in the XY plane so that the center coincides with the origin of the XYZ coordinate system Diaphragm 110, the support body 130 formed to extend downward from the other side edge of the diaphragm 110 to support the weight body 120 formed to extend downward from the center of the other surface of the diaphragm 110 and the diaphragm 110 It can be configured to include an error sensing means to detect the vibration direction converted by the coupling of the resonance mode, and by adopting the drive control means to correct the converted vibration direction, noise, when measuring the angular velocity, There is an effect that can prevent the occurrence of instability or crosstalk.

Description

Inertial Sensor

The present invention relates to an inertial sensor.

Recently, the inertial sensor is used for military equipment such as satellites, missiles, and unmanned aerial vehicles. It is used for various purposes such as navigation and navigation.

The inertial sensor is divided into an acceleration sensor that can measure linear motion and an angular velocity sensor that can measure rotational motion. Here, acceleration can be obtained by Newton's law of motion "F = ma", where "F" is the force acting on the object, "m" is the mass of the object, and "a" is the acceleration to be measured. Therefore, the acceleration a can be obtained by measuring the force F acting on the object and dividing it by the mass m of the object. In addition, the angular velocity can be obtained by the Coriolis Force "F = 2mΩ? V" equation, "F" is the Coriolis force acting on the object, "m" is the mass of the object, "Ω" is to measure Angular velocity, "v", is the velocity of motion of the object. At this time, since the movement speed v of the object and the mass m of the object are already recognized values, the angular velocity Ω can be obtained by measuring the Coriolis force F acting on the object. Meanwhile, the direction of the Coriolis force (F), the direction of the movement speed (v) and the reference axis of the angular velocity (Ω) should be perpendicular to each other.

As described above, when obtaining the angular velocity using the Coriolis force, in order to implement the movement speed v, the inertial sensor uses the driving means to oscillate in the direction perpendicular to the angular velocity (Ω) reference axis and the Coriolis force. Must be authorized. However, the vibration direction may deviate from the direction perpendicular to the angular velocity (Ω) reference axis and the Coriolis force by the coupling of the resonance mode, and thus noise and instability when measuring the angular velocity (Ω). Or there is a problem that crosstalk occurs.

The present invention has been made to solve the above problems, an object of the present invention is to provide an inertial sensor that can correct the vibration direction converted by the coupling of the resonance mode by employing the error detection means and the drive control means. It is to.

The inertial sensor according to a preferred embodiment of the present invention, the drive means for applying a driving force to generate a vibration to a second axis perpendicular to the first axis when detecting the angular velocity to rotate around the first axis, the first axis Detection means for detecting a Coriolis force on a third axis perpendicular to both the second axis and the second axis, error detection means for detecting vibration in a direction other than the second axis, and vibration in a direction other than the second axis detected by the error sensing electrode. And drive control means for applying a driving force so that vibration is generated only in the second axis by canceling the operation.

Here, the driving means, the detecting means, the error detecting means and the driving control means is provided on one surface, the diaphragm disposed in the XY plane so that the center coincides with the origin of the XYZ coordinate system, extending downward from the center of the other surface of the diaphragm It characterized in that it further comprises a support formed to extend downward from the other surface edge of the diaphragm so as to support the weight body and the diaphragm formed to.

The driving means may include a piezoelectric body and a driving electrode formed on the piezoelectric body, the detecting means may include the piezoelectric body and the detection electrode formed on the piezoelectric body, and the driving control means may include the piezoelectric body and the driving control electrode formed on the piezoelectric body. The error sensing means may include the piezoelectric body and the error sensing electrode formed on the piezoelectric body, or the piezoelectric body and the error sensing electrode formed on the piezoelectric body.

In addition, the piezoelectric body is partitioned into an inner annular region surrounding an origin of an XYZ coordinate system and an outer annular region surrounding the inner annular region, and the driving electrode is formed in an arc shape in the outer annular region. The detection electrode is formed in an arc shape in the inner annular region.

In addition, the piezoelectric body is partitioned into an inner annular region surrounding an origin of an XYZ coordinate system and an outer annular region surrounding the inner annular region, and the drive electrode is formed in an arc shape in the inner annular region. The detection electrode may be formed in an arc shape in the outer annular region.

The driving electrode may include a first driving electrode provided in the negative direction of the X axis and symmetrical with respect to the X axis, a second driving electrode symmetrically disposed with the first driving electrode with respect to the Y axis, and in the negative direction of the Y axis. And a third driving electrode symmetrical with respect to the Y axis and a fourth driving electrode symmetrically disposed with the third driving electrode with respect to the X axis, wherein the detection electrode is provided in the negative direction of the X axis and at the same time X A first detection electrode symmetrical with respect to the axis, a second detection electrode symmetrically disposed with the first detection electrode with respect to the Y axis, a third detection electrode provided with a negative direction of the Y axis and symmetrical with respect to the Y axis and the X axis And a fourth detection electrode arranged symmetrically with the third detection electrode as a reference.

In addition, on the XY plane, an axis that passes through the first and third quadrants of the XY coordinate system and forms a 45 ° axis in the X and Y axes is a V axis, an axis that passes the second and fourth quadrants of the XY coordinate system and 45 ° in the X and Y axes. When defined as a W axis, the error detection electrode is a first error detection electrode provided between the second drive electrode and the fourth drive electrode and symmetrical about the V axis, and the first error detection based on the W axis. A second error sensing electrode disposed symmetrically with the electrode, a third error sensing electrode provided between the first driving electrode and the fourth driving electrode and symmetrical with respect to the W axis and the third error sensing electrode with respect to the V axis; And a fourth error sensing electrode disposed symmetrically with the driving control electrode, wherein the driving control electrode includes a first driving control electrode and a W axis that are provided between the second detection electrode and the fourth detection electrode and are symmetrical with respect to the V axis. The first as a reference A second drive control electrode disposed symmetrically with the same control electrode, a third drive control electrode provided between the first detection electrode and the fourth detection electrode and symmetrical with respect to the W axis and the third drive with respect to the V axis; And a fourth driving control electrode symmetrically disposed with the control electrode.

In addition, on the XY plane, an axis that passes through the first and third quadrants of the XY coordinate system and forms a 45 ° axis in the X and Y axes is a V axis, an axis that passes the second and fourth quadrants of the XY coordinate system and 45 ° in the X and Y axes. When defined as a W axis, the error detection electrode includes a first error detection electrode provided between the second detection electrode and the fourth detection electrode and symmetrical with respect to the V axis, and the first error detection with respect to the W axis. A second error detection electrode disposed symmetrically with an electrode, a third error detection electrode provided between the first detection electrode and the fourth detection electrode and symmetrical with respect to the W axis, and the third error detection electrode with respect to the V axis; And a fourth error sensing electrode arranged symmetrically to the driving control electrode, wherein the driving control electrode includes a first driving control electrode and a W axis that are provided between the second driving electrode and the fourth driving electrode and are symmetrical with respect to the V axis. The first as a reference A second driving control electrode disposed symmetrically with the same control electrode, a third driving control electrode provided between the first driving electrode and the fourth driving electrode and symmetrical with respect to the W axis and the third driving with respect to the V axis; And a fourth driving control electrode symmetrically disposed with the control electrode.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, the terms or words used in this specification and claims are not to be interpreted in a conventional and dictionary sense, and the inventors may appropriately define the concept of terms in order to best describe their own invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

According to the present invention, it is possible to detect the vibration direction converted by the coupling of the resonance mode by employing the error detection means, and to correct the converted vibration direction by employing the drive control means, noise, instability when measuring the angular velocity Alternatively, there is an effect that can prevent crosstalk from occurring.

1 is a perspective view of an inertial sensor according to a preferred embodiment of the present invention;
2 is a plan view of the inertial sensor shown in FIG. 1;
3A to 3B are sectional views showing the polarization characteristics of the piezoelectric body;
4 to 5 are cross-sectional views taken along the XZ plane of the inertial sensor shown in FIG. 2;
6 is a perspective view illustrating a process of measuring the angular velocity based on the weight of the inertial sensor shown in FIG. 1;
FIG. 7 is a perspective view showing actual vibration of the weight shown in FIG. 6; FIG.
8 is a cross-sectional view taken along the WZ plane of the inertial sensor shown in FIG. 2 when the weight vibrates; And
9 is a cross-sectional view taken along the VZ plane of the inertial sensor shown in FIG. 2 when the weight vibrates.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. In addition, terms such as “first” and “second” are used to distinguish one component from another component, and the component is not limited by the terms. In the following description of the present invention, a detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of an inertial sensor according to a preferred embodiment of the present invention, Figure 2 is a plan view of the inertial sensor shown in FIG.

1 to 2, the inertial sensor according to the present embodiment is provided with a driving means, a detection means, an error detecting means and a drive control means 100 on one surface, so that the center coincides with the origin of the XYZ coordinate system. Diaphragm 110 disposed in the XY plane, the weight body 120 formed to extend downward from the center of the other surface of the diaphragm 110 and the support portion formed to extend downward from the other surface border of the diaphragm 110 to support the diaphragm 110 It is the structure containing 130.

The diaphragm 110 is elastically deformed according to the movement of the weight body 120 formed at the center thereof. The diaphragm 110 includes a driving means, a detecting means, an error detecting means, and a driving control means 100 on one surface thereof, and the other side of the edge region. Receive the support of the support 130 formed in. Here, the center of the diaphragm 110 coincides with the origin of the XYZ coordinate system, and the diaphragm 110 is formed of a plate-like structure and disposed on the XY plane. Meanwhile, the driving means, the detecting means, the error detecting means, and the driving control means 100 provided on one surface of the diaphragm 110 serve to substantially measure the acceleration or the angular velocity in the inertial sensor, which will be described later.

The weight body 120 is a displacement caused by the force or Coriolis force according to the acceleration, is formed extending from the center of the other surface of the diaphragm 110 to the lower side. Here, although the weight body 120 is cylindrical in the figure, it is not necessarily limited to this and can be formed in any shape known in the art, such as a fan (Fan) type.

The support 130 is formed in a hollow shape to support the diaphragm 110 to secure a space in which the weight body 120 may cause displacement or vibration. Here, the diaphragm 110 is formed to extend downward from the other surface edge.

On the other hand, the diaphragm 110, the weight body 120 and the support portion 130 may be formed separately and bonded to each other through a bonding process, but the SOI substrate is selected to simplify the manufacturing process and save manufacturing costs It is preferable to form by integrally etching by etching.

The driving means, the detecting means, the error detecting means, and the driving control means 100 may be implemented by forming a plurality of electrodes 150, 160, 170, and 180 on one piezoelectric body 140, which is a plate-like structure. For example, as shown in FIG. 2, the driving means may be implemented by forming four driving electrodes 150 on the piezoelectric body 140, and the detecting means may include four detection electrodes 160 on the piezoelectric body 140. It can be formed and implemented. In addition, the error sensing means may also be implemented by forming four error sensing electrodes 170 on the piezoelectric body 140, and the driving control means may be implemented by forming four driving control electrodes 180 on the piezoelectric body 140. However, since the error detection means may have a weak signal due to its relatively small area, it may be implemented by providing a separate piezoresistor and forming four error sensing electrodes 170 on the piezoresistor.

Here, the four driving electrodes 150 and the four detection electrodes 160 are each formed in an arc shape. Specifically, when the piezoelectric body 140 is partitioned into an inner annular region 143 surrounding the origin of the XYZ coordinate system and an outer annular region 145 surrounding the inner annular region 143, the outer annular region Four driving electrodes 150 are formed in an arc shape at 145 and four detection electrodes 160 are formed in an arc shape in the inner annular region 143. Here, the four driving electrodes 150 are provided in the negative direction of the X axis and at the same time, the first driving electrode 151 symmetrically with respect to the X axis, and the second driving electrode 151 symmetrically disposed with respect to the Y axis. The driving electrode 152, the third driving electrode 153 provided in the negative direction of the Y axis and symmetrical with respect to the Y axis, and the fourth driving electrode 154 symmetrically disposed with the third driving electrode 153 with respect to the X axis. It is composed of In addition, the four detection electrodes 160 are provided in the negative direction of the X-axis and at the same time symmetrical with respect to the X-axis, and the second detection electrodes 161 symmetrically disposed with respect to the Y-axis. The detection electrode 162, the third detection electrode 163 provided in the negative direction of the Y axis and symmetrical with respect to the Y axis, and the fourth detection electrode 164 symmetrically disposed with the third detection electrode 163 with respect to the X axis. It is composed of As described above, since the four driving electrodes 150 are symmetrical with respect to the X axis or the Y axis, the weight body 120 may be accurately vibrated in the required direction. In addition, since the four detection electrodes 160 are also symmetrical with respect to the X-axis or the Y-axis, the displacement of the weight body 120 may be accurately detected.

The four error sensing electrodes 170 may be provided between the four driving electrodes 150, respectively, and the four driving control electrodes 180 may be provided between the four detection electrodes 160. Specifically, on the XY plane, an axis that passes through the first and third quadrants of the XY coordinate system and forms 45 ° in the X and Y axes, passes through the V and 2 quadrants and the fourth quadrant of the XY coordinate system, The axis forming ° is defined as the W axis. In this case, the four error sensing electrodes 170 are provided between the second driving electrode 152 and the fourth driving electrode 154 and are symmetrical with respect to the V axis and based on the W axis and the first error sensing electrode 171. The third error sensing electrode 172 and the first driving electrode 151 and the fourth driving electrode 154 which are disposed symmetrically with respect to the first error sensing electrode 171 are provided between the third and symmetrical with respect to the W axis. The error detection electrode 173 and the fourth error detection electrode 174 disposed symmetrically with the third error detection electrode 173 with respect to the V axis are configured. In addition, the four driving control electrodes 180 are provided between the second detection electrode 162 and the fourth detection electrode 164 and are symmetrical with respect to the V axis and based on the W axis and the first driving control electrode 181. The third driving control electrode 182 disposed symmetrically with the first driving control electrode 181, the first detection electrode 161 and the fourth detection electrode 164 is provided between the third symmetrical with respect to the W axis The driving control electrode 183 and the fourth driving control electrode 184 disposed symmetrically with the third driving control electrode 183 based on the V axis. As described above, the four error detection electrodes 170 are symmetrical with respect to the W axis or the V axis, and thus can accurately detect the vibration error of the weight body 120. In addition, since the four driving control electrodes 180 are also symmetrical with respect to the W axis or the V axis, the vibration of the weight body 120 can be accurately corrected.

However, since the arrangement of the driving electrode 150, the detection electrode 160, the error sensing electrode 170, and the driving control electrode 180 is exemplary, the arrangement of the driving electrode 150 and the detection electrode 160 may be different from each other. Alternatively, the arrangement of the error sensing electrode 170 and the driving control electrode 180 may be changed. 10 to 12 are plan views according to a modified example of the inertial sensor shown in FIG. Examine the layout of the. As illustrated in FIG. 10, the arrangement of the error sensing electrode 170 and the driving control electrode 180 illustrated in FIG. 2 may be interchanged. That is, four error sensing electrodes 170 may be provided between four detection electrodes 160, and four driving control electrodes 180 may be provided between four driving electrodes 150, respectively. In addition, as illustrated in FIG. 11, the arrangement of the driving electrode 150 and the detection electrode 160 illustrated in FIG. 2 may be interchanged. That is, four driving electrodes 150 may be formed in an arc shape in the inner annular region 143, and four detection electrodes 160 may be formed in the outer annular region 145 in an arc shape. As shown in FIG. 12, the arrangement of the driving electrode 150 and the detection electrode 160 illustrated in FIG. 2 is interchanged, and the arrangement of the error sensing electrode 170 and the driving control electrode 180 is interchanged. Can be. That is, four driving electrodes 150 may be formed in an arc shape in the inner annular region 143, and four detection electrodes 160 may be formed in an arc shape in the outer annular region 145. The electrodes 170 may be provided between the four driving electrodes 150, respectively, and the four driving control electrodes 180 may be provided between the four detection electrodes 160, respectively. On the other hand, the drive electrode 150, the detection electrode 160, the error detection electrode 170 and the drive control electrode 180 is preferably formed on both sides of the piezoelectric body 140 in the same configuration as described above. However, the present invention is not necessarily limited thereto, and in order to simplify the electrode forming process, the electrodes 150, 160, 170, and 180 may be integrally formed on one surface selected from both sides of the piezoelectric body 140 without patterning, thereby forming a ground electrode. It can be used as an electrode.

On the other hand, the piezoelectric member 140 generates negative and positive charges on the electrodes 150, 160, 170, and 180 when mechanical stress is applied, and mechanical stress when the voltage is applied to the electrodes 150, 160, 170, and 180. There is a characteristic that occurs. 3A to 3B are cross-sectional views illustrating the polarization characteristics of the piezoelectric body, and the polarization characteristics of the piezoelectric body 140 will be described in detail with reference to this. First, when mechanical stress is applied to the piezoelectric body 140, as shown in FIG. 3A, when tensile stress is applied to the piezoelectric body 140, a positive charge is generated in the upper electrode 193 and the lower electrode ( 195) generates a negative charge. On the contrary, as shown in FIG. 3B, when compressive stress acts on the piezoelectric body 140, negative charges are generated on the upper electrode 193 and positive charges are generated on the lower electrode 195. That is, the type of electric charge generated in the upper electrode 193 and the lower electrode 195 varies depending on whether the mechanical stress applied to the piezoelectric body 140 is tensile stress or compressive stress. Meanwhile, referring to FIG. 3A to FIG. 3B, when the voltage is applied to the electrode 190, as shown in FIG. 3A, positive charge is applied to the upper electrode 193 and negative charge is applied to the lower electrode 195. When applied, tensile stress is generated in the piezoelectric body 140. On the contrary, as shown in FIG. 3B, when negative charge is applied to the upper electrode 193 and positive charge is applied to the lower electrode 195, compressive stress is generated in the piezoelectric body 140. That is, the kind of mechanical stress generated in the piezoelectric body 140 changes according to the electric charges applied to the upper electrode 193 and the lower electrode 195.

The displacement of the weight body 120 may be detected or the weight body 120 may be vibrated using the polarization characteristic of the piezoelectric body 140 described above. 4 to 5 are cross-sectional views of the inertial sensor shown in FIG. 2 taken along the XZ plane, and a process of detecting displacement of the weight body 120 or vibrating the weight body 120 will be described in detail. First, a process of detecting the displacement of the weight body 120 in the detection electrode 160 is as follows. As shown in FIG. 4A, when the displacement of Dx occurs in the positive direction of the X-axis in the center G of the weight body 120, the upper electrode 165 and the lower electrode of the first detection electrode 161 ( A negative charge and a positive charge are respectively generated at 167, and a positive charge and a negative charge are respectively generated at the upper electrode 166 and the lower electrode 168 of the second detection electrode 162. On the contrary, as shown in FIG. 4B, when -Dx displacement occurs in the negative direction of the X axis in the center G of the weight body 120, the upper electrode 165 of the first detection electrode 161 Positive and negative charges are generated on the lower electrode 167, respectively, and negative and positive charges are generated on the upper electrode 166 and the lower electrode 168 of the second detection electrode 162, respectively. Therefore, the amount of charge generated in the first detection electrode 161 and the second detection electrode 162 can be sensed to detect the X-axis displacement of the weight body 120. In addition, in the same manner as described above, the amount of charge generated in the third and fourth detection electrodes 163 and 164 may be detected to detect the displacement in the Y-axis direction of the weight body 120.

And, as shown in Figure 5a, when the displacement of Dz in the positive direction of the Z axis in the center (G) of the weight body 120, the first detection electrode 161 and the second detection electrode 162 Both positive and negative charges are generated in the upper electrodes 165 and 166 and the lower electrodes 167 and 168, respectively. On the contrary, as shown in FIG. 5B, when -Dz displacement occurs in the negative direction of the Z axis in the center G of the weight body 120, the first detection electrode 161 and the second detection electrode 162. Negative and positive charges are generated on the upper electrodes 165 and 166 and the lower electrodes 167 and 168, respectively. Therefore, the amount of charge generated in the first detection electrode 161 and the second detection electrode 162 may be sensed to detect the Z-axis displacement of the weight body 120. However, even when the third detection electrode 163 and the fourth detection electrode 164 are used, the Z-axis displacement can be detected in the same manner as the above-described process.

Meanwhile, the process of vibrating the weight body 120 using the driving electrode 150 will be described with reference to FIGS. 4 to 5 again. As shown in FIG. 4A, positive and negative charges are applied to the upper electrode 155 and the lower electrode 157 of the first driving electrode 151 and the upper electrode 156 and the lower of the second driving electrode 152, respectively. When negative and positive charges are respectively applied to the electrode 158, the force of Fx is applied to the center G of the weight body 120 in the positive direction of the X axis. On the contrary, as shown in FIG. 4B, negative and positive charges are applied to the upper electrode 155 and the lower electrode 157 of the first driving electrode 151, respectively, and the upper electrode 156 of the second driving electrode 152 is applied. When positive and negative charges are respectively applied to the and lower electrodes 158, a force of −Fx is applied to the center G of the weight body 120 in the negative direction of the X axis. Therefore, when an alternating voltage of a certain period is applied to the first driving electrode 151 and the second driving electrode 152, the weight body 120 may be vibrated in the X-axis direction. In addition, in the same manner as described above, when the AC voltage of a predetermined period is applied to the third driving electrode 153 and the fourth driving electrode 154, the weight body 120 may be vibrated in the Y-axis direction.

As shown in FIG. 5A, negative and positive charges are applied to the upper electrode 155 and the lower electrode 157 of the first driving electrode 151, respectively, and the upper electrode 156 of the second driving electrode 152 is applied. When negative and positive charges are respectively applied to the and lower electrodes 158, the force of Fx is applied to the center G of the weight body 120 in the positive direction of the Z axis. On the contrary, as shown in FIG. 5B, positive and negative charges are applied to the upper electrode 155 and the lower electrode 157 of the first driving electrode 151, respectively, and the upper electrode 156 of the second driving electrode 152 is applied. When positive and negative charges are respectively applied to the and lower electrodes 158, a force of −Fx is applied to the center G of the weight body 120 in the negative direction of the Z axis. Therefore, the AC 120 may be vibrated in the Z-axis direction by applying an alternating-current voltage to the first driving electrode 151 and the second driving electrode 152. However, even when the third driving electrode 153 and the fourth driving electrode 154 are used, the weight body 120 may be vibrated in the Z-axis direction in the same manner as described above.

As a result, since the polarization characteristics of the piezoelectric body 140 may be used to detect displacement in all directions with respect to the weight body 120 or vibrate the weight body 120 in all directions, the inertial sensor according to the present exemplary embodiment may have acceleration and acceleration. The angular velocity can be measured. For example, the first detection electrode 161 and the second detection electrode 162 detect the X-axis displacement of the weight body 120 to calculate the force F in the X-axis direction applied to the weight body 120. When the force F is divided by the mass m of the weight body 120, the acceleration a in the X-axis direction can be measured. However, since the angular velocity (Ω) should be measured using a Coriolis Force (F), the weight body 120 should be vibrated in the vertical direction of the angular velocity (Ω) reference axis. At this time, the direction of the Coriolis force, the direction in which the weight body 120 vibrates and the reference axis of the angular velocity (Ω) should be perpendicular to each other. FIG. 6 is a perspective view illustrating a process of measuring angular velocity based on the weight of the inertial sensor illustrated in FIG. 1, and a process of measuring the angular velocity of the inertial sensor will be described with reference to FIG. As shown in FIG. 6, when the angular velocity Ω that is rotated with respect to the Z axis is to be measured, the X-axis of the weight body 120 is formed using the first driving electrode 151 and the second driving electrode 152. Vibration at a constant speed v in the direction generates a Coriolis force F in the Y-axis direction. In this case, the mass m of the weight body 120 is a fixed value and the constant speed v at which the weight body 120 vibrates may be controlled by the first driving electrode 151 and the second driving electrode 152. have. Accordingly, when the Coriolis force F acting on the weight body 120 is detected by detecting the Y-axis displacement with the third and fourth detection electrodes 163 and 164, the equation " F = 2mΩ? V " The angular velocity (Ω) can be measured by using. As a result, in order to measure the angular velocity Ω through the Coriolis force F, the weight body 120 should be vibrated at a constant speed v in the X-axis direction (the vertical direction of the angular velocity Ω reference axis). However, when the weight body 120 is vibrated in the X-axis direction using the first driving electrode 151 and the second driving electrode 152, the weight body 120 is actually caused by coupling in a resonance mode. There is a problem that vibrates out of the X-axis direction. In order to solve such a problem, the inertial sensor according to the present embodiment employs an error sensing electrode 170 and a driving control electrode 180, and the error sensing electrode 170 and the driving control electrode 180 are detection electrodes, respectively. Similar to the 160 and the driving electrode 150, the polarization characteristics of the piezoelectric body 140 are used. Hereinafter, the error sensing electrode 170 and the driving control electrode 180 will be described in detail.

FIG. 7 is a perspective view illustrating actual vibration of the weight shown in FIG. 6, FIG. 8 is a cross-sectional view of the inertial sensor shown in FIG. 2 taken along the WZ plane when the weight vibrates, and FIG. 2 is a cross-sectional view taken along the VZ plane of the inertial sensor shown in FIG. 2.

In order to measure the angular velocity Ω that rotates about the Z axis using the Coriolis force F, for example, the first driving electrode 151 and the second driving electrode 152 as shown in FIGS. 4A to 4B. ) To vibrate the weight body 120 in the X-axis direction. However, due to the coupling (coupling) of the resonance mode, the weight body 120 may actually vibrate along the direction (B direction) rather than the X-axis direction (A direction) (see FIG. 7). At this time, assuming that the B direction in which the weight body 120 vibrates is parallel to the W axis, the center G of the weight body 120 is displaced in the positive direction and the negative direction of the W axis. Therefore, as shown in FIG. 8A, when the center G of the weight body 120 has a displacement of Dw in the positive direction of the W axis, the upper electrode 175 of the third error detection electrode 173 Negative and positive charges are respectively generated on the lower electrode 177, and positive and negative charges are generated on the upper electrode 176 and the lower electrode 178 of the fourth error sensing electrode 174, respectively. On the contrary, as shown in FIG. 8B, when the center G of the weight body 120 has a displacement of −Dw in the negative direction of the W axis, the upper electrode 175 of the third error sensing electrode 173 is generated. Positive and negative charges are generated on the and lower electrodes 177, respectively, and negative and positive charges are respectively generated on the upper electrode 176 and the lower electrode 178 of the fourth error sensing electrode 174. As a result, the amount of charge generated in the third error detection electrode 173 and the fourth error detection electrode 174 is sensed so that the weight body 120 vibrates in the W axis direction (B direction) out of the X axis direction (A direction). You can detect that. However, as described above, when the error sensing means is formed of a piezo resistor instead of the piezoelectric body 140, the weight 120 is measured in the X axis direction (A direction) by measuring a change in resistance generated by the error sensing electrode 170. It can be detected that the vibration in the W-axis direction (B direction) out of the (). At this time, it is possible to measure the degree of deviation from the vibration direction from the magnitude of the above-described change in the amount of charge or resistance. In addition, since the vibration component in the Y-axis direction due to the Coriolis force has a phase difference of π / 2 with respect to the vibration in the X-axis direction, it can be separated from the above-described change in charge amount or resistance signal.

Since the weight body 120 is detected to vibrate in the W-axis direction (B direction) through the error sensing electrode 170, the driving control electrode 180 cancels the vibration in the W-axis direction (B direction) and thus the X-axis direction. Driving force should be applied to generate vibration only in (A direction). Specifically, since the vibration in the W-axis direction (B direction) should be canceled, the driving control electrode 180 is predetermined on the weight body 120 in the V-axis direction (C direction) perpendicular to the W-axis direction (B direction). You must apply power. Accordingly, as shown in FIG. 9A, positive and negative charges are applied to the upper electrode 185 and the lower electrode 187 of the first driving control electrode 181, respectively, and the upper electrode of the second driving control electrode 182 ( A negative charge and a positive charge are applied to the 186 and the lower electrode 188, respectively, to apply a force of Fv to the center G of the weight body 120. Alternately with the force of the Fv, as shown in FIG. 9B, negative and positive charges are applied to the upper electrode 185 and the lower electrode 187 of the first driving control electrode 181, respectively, and the second driving control electrode ( Positive and negative charges are applied to the upper electrode 186 and the lower electrode 188 of 182 to apply a force of -Fv to the center G of the weight body 120, respectively. That is, the force of Fv and the force of -Fv are applied in the V-axis direction (C direction) at the same period as the vibration of the weight body 120 using the first driving control electrode 181 and the second driving control electrode 182. By doing so, the weight body 120 can be vibrated only by the X axis.

However, the above-described X-axis direction, W-axis direction and V-axis direction is an example for convenience of description. That is, in the inertial sensor according to the present embodiment, in order to detect an angular velocity that is rotated about an arbitrary first axis, a combination of four driving electrodes 150 is used to make the weight body 120 perpendicular to the first axis. It can vibrate in the axial direction. At this time, even if the vibration of the weight body 120 is irregularly converted in a direction other than the second axis, it is possible to detect the vibration in the direction other than the second axis by using the four error detection electrodes 170, the error detection Based on the vibration sensed by the electrode 170, the four driving control electrodes 180 may be combined to apply a driving force to correct the weight body 120 to vibrate only on the second axis.

The inertial sensor according to the present embodiment employs an error detecting means to detect a vibration direction converted by the coupling of the resonance mode, and employs a drive control means to correct the converted vibration direction to measure the angular velocity. There is an effect that can prevent the occurrence of noise, instability or crosstalk.

Although the present invention has been described in detail through specific embodiments, this is for explaining the present invention in detail, and the inertial sensor according to the present invention is not limited thereto, and the general knowledge of the art within the technical spirit of the present invention is provided. It is obvious that modifications and improvements are possible by those who have them. All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

100: drive means, detection means, error detection means and drive control means
110: diaphragm 120: weight
130: support portion 140: piezoelectric body
143: inner annular region 145: outer annular region
150: driving electrode 151: first driving electrode
152: second driving electrode 153: third driving electrode
154: fourth driving electrode 155, 156: upper electrode of the driving electrode
157 and 158: lower electrode of the driving electrode 160: detection electrode
161: first detection electrode 162: second detection electrode
163: third detection electrode 164: fourth detection electrode
165, 166: upper electrode of detection electrode 167, 168: lower electrode of detection electrode
170: error detection electrode 171: first error detection electrode
172: second error detection electrode 173: third error detection electrode
174: fourth error detecting electrode
175, 176: upper electrode of the error detection electrode
177, 178: lower electrode of the error detection electrode
180: driving control electrode
181: first drive control electrode 182: second drive control electrode
183: third drive control electrode 184: fourth drive control electrode
185, 186: upper electrode of the driving control electrode
187 and 188: lower electrode of the driving control electrode
190: electrode 193: upper electrode
195: lower electrode

Claims

Drive means for applying a driving force to generate vibration in a second axis perpendicular to the first axis when detecting an angular velocity rotating about a first axis;
Detecting means for detecting a Coriolis force on a third axis that is perpendicular to both the first axis and the second axis;
Error sensing means for sensing vibration in a direction other than the second axis;
Drive control means for canceling the vibration in a direction other than the second axis sensed by the error sensing electrode and applying a driving force to generate vibration only in the second axis;
An inertial sensor comprising a.

The method according to claim 1,
A diaphragm having the driving means, the detecting means, the error detecting means, and the driving control means on one surface, the diaphragm being disposed in an XY plane so that its center coincides with the origin of the XYZ coordinate system;
A weight formed to extend downward from a center of the other surface of the diaphragm; And
A support formed to extend downwardly from an edge of the other surface of the diaphragm to support the diaphragm;
Inertial sensor, characterized in that it further comprises.

The method according to claim 2,
The driving means includes a piezoelectric body and a driving electrode formed on the piezoelectric body,
The detecting means includes the piezoelectric body and a detection electrode formed on the piezoelectric body,
The drive control means includes the piezoelectric body and a drive control electrode formed on the piezoelectric body,
The error detecting means includes an piezoelectric body and an error sensing electrode formed on the piezoelectric body, or an inertial sensor and an error sensing electrode formed on the piezoelectric body.

The method according to claim 3,
The piezoelectric body is partitioned into an inner annular region surrounding the origin of the XYZ coordinate system and an outer annular region surrounding the inner annular region,
The driving electrode is formed in an arc shape in the outer annular region,
And the detection electrode is formed in an arc shape in the inner annular region.

The method according to claim 3,
The piezoelectric body is partitioned into an inner annular region surrounding the origin of the XYZ coordinate system and an outer annular region surrounding the inner annular region,
The driving electrode is formed in an arc shape in the inner annular region,
And the detection electrode is formed in an arc shape in the outer annular area.

The method of claim 4,
The drive electrode,
A first drive electrode provided in the negative direction of the X axis and symmetrical with respect to the X axis, a second drive electrode symmetrically disposed with the first drive electrode with respect to the Y axis, and provided in the negative direction of the Y axis and simultaneously with respect to the Y axis A symmetric third driving electrode and a fourth driving electrode symmetrically disposed with respect to the third driving electrode with respect to the X axis,
The detection electrode,
A first detection electrode provided in the negative direction of the X axis and symmetrical with respect to the X axis, a second detection electrode disposed symmetrically with the first detection electrode with respect to the Y axis, and provided in the negative direction of the Y axis and simultaneously with respect to the Y axis And a fourth detection electrode symmetrically disposed with respect to the third detection electrode based on the symmetric third detection electrode and the X axis.

The method according to claim 5,
The drive electrode,
A first drive electrode provided in the negative direction of the X axis and symmetrical with respect to the X axis, a second drive electrode symmetrically disposed with the first drive electrode with respect to the Y axis, and provided in the negative direction of the Y axis and simultaneously with respect to the Y axis A symmetric third driving electrode and a fourth driving electrode symmetrically disposed with respect to the third driving electrode with respect to the X axis,
The detection electrode,
A first detection electrode provided in the negative direction of the X axis and symmetrical with respect to the X axis, a second detection electrode disposed symmetrically with the first detection electrode with respect to the Y axis, and provided in the negative direction of the Y axis and simultaneously with respect to the Y axis And a fourth detection electrode symmetrically disposed with respect to the third detection electrode based on the symmetric third detection electrode and the X axis.

The method of claim 6,
On the XY plane, the axes that pass through the first and third quadrants of the XY coordinate system and form a 45 ° axis in the X and Y axes are the V axis, and the axes that pass the second and fourth quadrants of the XY coordinate system and 45 ° in the X and Y axis axes. When we define as
The error detecting electrode,
A first error sensing electrode provided between the second driving electrode and the fourth driving electrode and symmetrical with respect to the V axis, and a second error sensing electrode disposed symmetrically with the first error sensing electrode with respect to the W axis; A third error sensing electrode provided between the first driving electrode and the fourth driving electrode and symmetrical with respect to the W axis, and a fourth error sensing electrode disposed symmetrically with the third error sensing electrode with respect to the V axis; ,
The drive control electrode,
A first drive control electrode disposed between the second detection electrode and the fourth detection electrode and symmetrical with respect to the V axis, and a second drive control electrode disposed symmetrically with the first drive control electrode with respect to the W axis; A third driving control electrode disposed between the first detection electrode and the fourth detection electrode and symmetrical with respect to the W axis and a fourth driving control electrode disposed symmetrically with the third driving control electrode with respect to the V axis; Inertial sensor, characterized in that.

The method of claim 6,
On the XY plane, the axes that pass through the first and third quadrants of the XY coordinate system and form a 45 ° axis in the X and Y axes are the V axis, and the axes that pass the second and fourth quadrants of the XY coordinate system and 45 ° in the X and Y axis axes. When we define as
The error detecting electrode,
A first error detection electrode disposed between the second detection electrode and the fourth detection electrode and symmetrical with respect to the V axis, and a second error detection electrode disposed symmetrically with the first error detection electrode with respect to the W axis; A third error detection electrode disposed between the first detection electrode and the fourth detection electrode and symmetrical with respect to the W axis and a fourth error detection electrode disposed symmetrically with the third error detection electrode with respect to the V axis; ,
The drive control electrode,
A first driving control electrode disposed between the second driving electrode and the fourth driving electrode and symmetrical with respect to the V axis, and a second driving control electrode disposed symmetrically with the first driving control electrode with respect to the W axis; A third driving control electrode provided between the first driving electrode and the fourth driving electrode and symmetrical with respect to the W axis and a fourth driving control electrode disposed symmetrically with the third driving control electrode with respect to the V axis; Inertial sensor, characterized in that.

The method of claim 7,
On the XY plane, the axes that pass through the first and third quadrants of the XY coordinate system and form a 45 ° axis in the X and Y axes are the V axis, and the axes that pass the second and fourth quadrants of the XY coordinate system and 45 ° in the X and Y axis axes. When we define as
The error detecting electrode,
A first error sensing electrode provided between the second driving electrode and the fourth driving electrode and symmetrical with respect to the V axis, and a second error sensing electrode disposed symmetrically with the first error sensing electrode with respect to the W axis; A third error sensing electrode provided between the first driving electrode and the fourth driving electrode and symmetrical with respect to the W axis, and a fourth error sensing electrode disposed symmetrically with the third error sensing electrode with respect to the V axis; ,
The drive control electrode,
A first drive control electrode disposed between the second detection electrode and the fourth detection electrode and symmetrical with respect to the V axis, and a second drive control electrode disposed symmetrically with the first drive control electrode with respect to the W axis; A third driving control electrode disposed between the first detection electrode and the fourth detection electrode and symmetrical with respect to the W axis and a fourth driving control electrode disposed symmetrically with the third driving control electrode with respect to the V axis; Inertial sensor, characterized in that.

The method of claim 7,
On the XY plane, the axes that pass through the first and third quadrants of the XY coordinate system and form a 45 ° axis in the X and Y axes are the V axis, and the axes that pass the second and fourth quadrants of the XY coordinate system and 45 ° in the X and Y axis axes. When we define as
The error detecting electrode,
A first error detection electrode disposed between the second detection electrode and the fourth detection electrode and symmetrical with respect to the V axis, and a second error detection electrode disposed symmetrically with the first error detection electrode with respect to the W axis; A third error detection electrode disposed between the first detection electrode and the fourth detection electrode and symmetrical with respect to the W axis and a fourth error detection electrode disposed symmetrically with the third error detection electrode with respect to the V axis; ,
The drive control electrode,
A first driving control electrode disposed between the second driving electrode and the fourth driving electrode and symmetrical with respect to the V axis, and a second driving control electrode disposed symmetrically with the first driving control electrode with respect to the W axis; A third driving control electrode provided between the first driving electrode and the fourth driving electrode and symmetrical with respect to the W axis and a fourth driving control electrode disposed symmetrically with the third driving control electrode with respect to the V axis; Inertial sensor, characterized in that.