阅读说明：本技术 一种三轴石英挠性加速度计总成及其测量方法 (Triaxial quartz flexible accelerometer assembly and measuring method thereof ) 是由 徐鑫 刘骅峰 刘发 阮晓明 郑东飞 于 2020-07-31 设计创作，主要内容包括：本发明一种三轴石英挠性加速度计总成,包括测量部件和数据转换部件；测量部件包括安装平台和三个石英挠性加速度计；安装平台呈三棱锥状,三个石英挠性加速度计分别对应固定设置在安装平台的三个侧面,安装平台的底面水平设置；三个石英挠性加速度计形成的轴线之间相互垂直,三个石英挠性加速度计的轴线之间沿水平面的夹角等分；一种加速度测量方法,步骤1,将三个石英挠性加速度计的敏感轴分别定义为U、V、W坐标轴,测量得到UVW坐标系下的加速度；步骤2,通过数据转换部件将UVW坐标系下的加速度转换为XYZ坐标系下的加速度,对外输出XYZ坐标系下的X、Y、Z三个轴向的加速度数字信号。结构简单,无需对石英挠性加速度计进行特殊设计。(The invention relates to a triaxial quartz flexible accelerometer assembly, which comprises a measuring component and a data conversion component, wherein the measuring component is connected with the data conversion component; the measuring component comprises a mounting platform and three quartz flexible accelerometers; the mounting platform is in a triangular pyramid shape, the three quartz flexible accelerometers are respectively and fixedly arranged on three side surfaces of the mounting platform correspondingly, and the bottom surface of the mounting platform is horizontally arranged; the axes formed by the three quartz flexible accelerometers are mutually vertical, and the included angles between the axes of the three quartz flexible accelerometers along the horizontal plane are equally divided; an acceleration measuring method comprises the steps of 1, defining sensitive axes of three quartz flexible accelerometers as U, V, W coordinate axes respectively, and measuring to obtain acceleration under a UVW coordinate system; and 2, converting the acceleration under the UVW coordinate system into the acceleration under the XYZ coordinate system through a data conversion component, and outputting X, Y, Z three-axial acceleration digital signals under the XYZ coordinate system. The structure is simple, and the quartz flexible accelerometer is not required to be specially designed.)

1. A triaxial quartz flexible accelerometer assembly is characterized by comprising a measuring component and a data conversion component; the measuring component measures the acceleration under the UVW coordinate, and the data conversion component converts the acceleration under the UVW coordinate into the acceleration under an XYZ rectangular coordinate system;

the measuring component comprises a mounting platform (4) and three quartz flexible accelerometers (3);

the mounting platform (4) is in a triangular pyramid shape, the three quartz flexible accelerometers (3) are respectively and fixedly arranged on three side surfaces of the mounting platform (4) correspondingly, and the bottom surface of the mounting platform (4) is horizontally arranged; the axes formed by the three quartz flexible accelerometers (3) are mutually vertical, and the included angles between the axes of the three quartz flexible accelerometers (3) along the horizontal plane are equally divided;

the data conversion part comprises an analog-digital conversion unit and an FPGA signal processing unit;

the output ends of the three quartz flexible accelerometers (3) are connected with the input end of an analog-to-digital conversion unit, the output end of the analog-to-digital conversion unit is connected with the input end of an FPGA signal processing unit, and the output end of the FPGA signal processing unit is connected with a digital system.

2. The triaxial quartz flexible accelerometer assembly of claim 1, wherein a circuit board (6) and a metal base (7) are sequentially arranged at the bottom of the mounting platform (4), the data conversion component is arranged on the circuit board (6), a mounting hole of the quartz flexible accelerometer on the mounting platform (4) is a through hole, an output end of the quartz flexible accelerometer passes through the through hole and is connected with an input end of the data conversion component at the bottom, an outlet end interface (8) is arranged on the metal base (7), and an output end of the data conversion component is connected with the outlet end interface (8).

3. The triaxial quartz flexure accelerometer assembly of claim 1, further comprising a temperature control system, the temperature control system comprising a heating device, a temperature measuring device, and a control device; the heating device heats the measuring part, the temperature measuring device measures the heating temperature of the heating device, and the control device controls the heating device;

the heating device comprises a metal sleeve (1) and a heater, the temperature measuring device comprises a constant current source, a Wheatstone bridge and an instrument amplifier, and the control device comprises a PID controller, a pulse width modulator and a power driving circuit; the Wheatstone bridge comprises a thermistor Rt and three debugging resistors Rc; the constant current source comprises a precision voltage reference, an operational amplifier and a precision resistor Rp;

the metal sleeve (1) is sleeved on the outer side of the measuring part, a heater is fixedly arranged on the outer side of the metal sleeve (1), and the thermistor Rt is fixedly arranged between the heater and the metal sleeve (1); the output end of the precision voltage reference is connected with the non-inverting input end of the operational amplifier, the output end of the operational amplifier is connected with the input end of the Wheatstone bridge, the output end of the diagonal angle of the input end is connected with the input end of the precision resistor Rp and the reverse input end of the operational amplifier, the output end of the precision resistor Rp is grounded, the other two output ends of the Wheatstone bridge are connected with the input end of the instrumentation amplifier, the output end of the instrumentation amplifier is connected with the input end of the PID controller, the output end of the PID controller is connected with the input end of the pulse width modulator, the output end of the pulse width modulator is connected with the input.

4. The triaxial quartz flexure accelerometer assembly of claim 3, wherein the PID controller comprises a debug resistor, a current limiting resistor R5, a debug capacitor and an operational amplifier;

the debugging resistor comprises a resistor R1, a resistor R2, a resistor R3 and a resistor R4, and the debugging capacitor comprises a capacitor C1 and a capacitor C2;

the input ends of the resistor R1 and the capacitor C1 are connected with the output end of the instrumentation amplifier, the output end of the resistor R1 is connected with the inverting input end of the operational amplifier, the output end of the capacitor C1 is connected with the input end of the resistor R2, the output end of the resistor R2 is connected with the inverting input end of the operational amplifier, the input end of the capacitor C2 is connected with the inverting input end of the operational amplifier, the output end of the capacitor C2 is connected with the input end of the resistor R4, and the output end of the resistor R4 is connected with the; the input end of the resistor R3 is connected with the inverting input end of the operational amplifier, and the output end of the resistor R3 is connected with the output end of the operational amplifier; the input end of the current limiting resistor R5 is connected with the non-inverting input end of the operational amplifier, and the output end of the current limiting resistor R5 is grounded.

5. The triaxial quartz flexible accelerometer assembly of claim 3, wherein the pulse width modulator comprises a sawtooth generator and a voltage comparator;

the output end of the PID controller is connected with the inverting input end of the voltage comparator, the output end of the sawtooth wave generator is connected with the non-inverting input end of the voltage comparator, the output end of the voltage comparator is connected with the input end of the resistor, the output end of the current-limiting resistor is connected with the base electrode of the Darlington structure transistor, the collector electrode of the Darlington structure transistor is connected with the heater, and the emitter electrode of the Darlington structure transistor is.

6. The assembly according to claim 2 or 3, wherein the metal sleeve (1) and the metal base (7) are sealingly connected to form a sealed space, and the measuring unit and the data converting unit are disposed within the sealed space.

7. A triaxial quartz flexure accelerometer assembly according to claim 1, wherein the quartz flexure accelerometer is fixed to the mounting platform (4) by screws (2).

8. An acceleration measurement method, characterized in that the triaxial quartz flexure accelerometer assembly according to any of claims 1-7, comprises the following process,

step 1, defining the sensitive axes of three quartz flexible accelerometers (3) as U, V, W coordinate axes respectively, and measuring to obtain the acceleration under a UVW coordinate system;

and 2, converting the acceleration under the UVW coordinate system into the acceleration under the XYZ coordinate system through a data conversion component, and outputting X, Y, Z three-axial acceleration digital signals under the XYZ coordinate system.

9. The acceleration measuring method of claim 8, wherein the UVW coordinate system is transformed into XYZ rectangular coordinate system according to the following formula:

Technical Field

The invention relates to the field of inertial measurement, in particular to a triaxial quartz flexible accelerometer assembly and a measurement method thereof.

Background

An Inertial Measurement Unit (IMU) measures three axial angular velocities and accelerations of a carrier in an Inertial reference system, and performs integral calculation on time to obtain velocity, yaw angle and other position information of the carrier in a navigation coordinate system, and the IMU is a core information source of an Inertial navigation system. In addition, the inertia measurement unit is also widely applied to various national defense and civil fields such as remote weapon accurate guidance, satellite attitude control, petroleum geological exploration, railway track inspection vehicle vibration measurement and the like, and has extremely high military and social benefits.

As an important instrument of the IMU, the performance of the tri-axial accelerometer directly affects the overall performance of the navigation system. The quartz flexible accelerometer has the characteristics of high precision, small volume, low energy consumption, high reliability and the like, and is a preferred device of the IMU at present. Typically, three uniaxial quartz flexure accelerometers are placed orthogonal to each other, two of which are placed horizontally orthogonal to each other and the third is placed vertically to form the most basic cartesian coordinate system, thereby achieving three axial XYZ acceleration measurements. When the accelerometer configuration mode is used, under the influence of the gravity acceleration of the earth, the transmission structure of the quartz flexible accelerometer arranged in the vertical direction can be subjected to continuous external stress, so that the quartz flexible accelerometer in the three directions has different working states, wherein in a static state, the x axis is 0g, the y axis is 0g, and the z axis is +1g or-1 g. The continuous external stress can accelerate the service life of the aged quartz flexible accelerometer, and amplify the measurement error of the quartz flexible accelerometer in three axial directions caused by process error, so that the special design of the z-axis accelerometer is required in some precise measurement fields. In addition, when the inertial navigation system uses acceleration components in three axial directions of XYZ, the influence of real-time gravitational acceleration needs to be eliminated in advance, and the gravitational acceleration changes along with the ground height, the latitude, the distribution of nearby mineral deposits and the like, so that the complexity of the inertial navigation system is improved.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides the triaxial quartz flexible accelerometer assembly and the measurement method thereof, which have simple structure, do not need to specially design the quartz flexible accelerometer, and simultaneously reduce the influence of the gravity acceleration on the triaxial accelerometer.

The invention is realized by the following technical scheme:

a triaxial quartz flexible accelerometer assembly comprises a measuring component and a data conversion component; the measuring component measures the acceleration under the UVW coordinate, and the data conversion component converts the acceleration under the UVW coordinate into the acceleration under an XYZ rectangular coordinate system;

the measuring component comprises a mounting platform and three quartz flexible accelerometers;

the mounting platform is in a triangular pyramid shape, the three quartz flexible accelerometers are respectively and fixedly arranged on three side surfaces of the mounting platform correspondingly, and the bottom surface of the mounting platform is horizontally arranged; the axes formed by the three quartz flexible accelerometers are mutually vertical, and the included angles between the axes of the three quartz flexible accelerometers along the horizontal plane are equally divided;

the data conversion part comprises an analog-digital conversion unit and an FPGA signal processing unit;

the output ends of the three quartz flexible accelerometers are all connected with the input end of the analog-to-digital conversion unit, the output end of the analog-to-digital conversion unit is connected with the input end of the FPGA signal processing unit, and the output end of the FPGA signal processing unit is connected with the digital system.

Preferably, the mounting platform bottom has set gradually circuit board and metal base, the data conversion part sets up on the circuit board, the mounting hole of quartzy flexible accelerometer on the mounting platform is the through-hole, and the output of quartzy flexible accelerometer passes the through-hole and is connected with the input of the data conversion part of bottom, be provided with on the metal base and draw forth the end interface, the output connection of data conversion part draws forth the end interface.

Preferably, the device also comprises a temperature control system, wherein the temperature control system comprises a heating device, a temperature measuring device and a control device; the heating device heats the measuring part, the temperature measuring device measures the heating temperature of the heating device, and the control device controls the heating device;

the heating device comprises a metal sleeve and a heater, the temperature measuring device comprises a constant current source, a Wheatstone bridge and an instrument amplifier, and the control device comprises a PID controller, a pulse width modulator and a power driving circuit; the Wheatstone bridge comprises a thermistor Rt and three debugging resistors Rc; the constant current source comprises a precision voltage reference, an operational amplifier and a precision resistor Rp;

the metal sleeve is sleeved outside the measuring component, a heater is fixedly arranged outside the metal sleeve, and the thermistor Rt is fixedly arranged between the heater and the metal sleeve; the output end of the precision voltage reference is connected with the non-inverting input end of the operational amplifier, the output end of the operational amplifier is connected with the input end of the Wheatstone bridge, the output end of the diagonal angle of the input end is connected with the input end of the precision resistor Rp and the reverse input end of the operational amplifier, the output end of the precision resistor Rp is grounded, the other two output ends of the Wheatstone bridge are connected with the input end of the instrumentation amplifier, the output end of the instrumentation amplifier is connected with the input end of the PID controller, the output end of the PID controller is connected with the input end of the pulse width modulator, the output end of the pulse width modulator is connected with the input.

Further, the PID controller comprises a debugging resistor, a current limiting resistor R5, a debugging capacitor and an operational amplifier;

the debugging resistors are respectively a resistor R1, a resistor R2, a resistor R3 and a resistor R4, and the debugging capacitors are respectively a capacitor C1 and a capacitor C2;

the input ends of the resistor R1 and the capacitor C1 are connected with the output end of the instrumentation amplifier, the output end of the resistor R1 is connected with the inverting input end of the operational amplifier, the output end of the capacitor C1 is connected with the input end of the resistor R2, the output end of the resistor R2 is connected with the inverting input end of the operational amplifier, the input end of the capacitor C2 is connected with the inverting input end of the operational amplifier, the output end of the capacitor C2 is connected with the input end of the resistor R4, and the output end of the resistor R4 is connected with the; the input end of the resistor R3 is connected with the inverting input end of the operational amplifier, and the output end of the resistor R3 is connected with the output end of the operational amplifier; the input end of the current limiting resistor R5 is connected with the non-inverting input end of the operational amplifier, and the output end of the current limiting resistor R5 is grounded.

Further, the pulse width modulator comprises a sawtooth wave generator and a voltage comparator;

the output end of the PID controller is connected with the inverting input end of the voltage comparator, the output end of the sawtooth wave generator is connected with the non-inverting input end of the voltage comparator, the output end of the voltage comparator is connected with the input end of the resistor, the output end of the current-limiting resistor is connected with the base electrode of the Darlington structure transistor, the collector electrode of the Darlington structure transistor is connected with the heater, and the emitter electrode of the Darlington structure transistor is.

Furthermore, the metal sleeve and the metal base are connected in a sealing mode to form a sealing space, and the measuring component and the data conversion component are arranged in the sealing space.

Preferably, the quartz flexible accelerometer is fixed on the mounting platform through screws.

An acceleration measurement method based on the triaxial quartz flexible accelerometer assembly of any one of the above, comprising the following processes,

step 1, defining the sensitive axes of three quartz flexible accelerometers as U, V, W coordinate axes respectively, and measuring to obtain the acceleration under a UVW coordinate system;

and 2, converting the acceleration under the UVW coordinate system into the acceleration under the XYZ coordinate system through a data conversion component, and outputting X, Y, Z three-axial acceleration digital signals under the XYZ coordinate system.

Preferably, the UVW coordinate transformation XYZ rectangular coordinate system has a formula:

compared with the prior art, the invention has the following beneficial technical effects:

the invention discloses a triaxial quartz flexible accelerometer assembly, which is characterized in that three quartz flexible accelerometers are arranged in a Galperin three-component configuration mode to measure the acceleration under a UVW coordinate, the acceleration under the UVW coordinate is converted into the acceleration under an XYZ rectangular coordinate system through a data conversion component, and the measurement of the acceleration in three axial directions of XYZ under the traditional Cartesian coordinate system is realized. The three quartz flexible accelerometers in the invention have the same structure and the same external stress, thereby avoiding the special design of the z-axis accelerometer in the traditional quartz flexible accelerometer and avoiding distinguishing the z-axis device from the x-axis device and the y-axis device, thereby reducing the design difficulty and the processing difficulty of the inertia measurement unit. When the method is applied, the influence of the gravity acceleration of the external environment on a measurement system is not required to be considered, and the design difficulty of a rear-stage inertial navigation system, an inclination measurement system, a vibration measurement system and the like is reduced.

The temperature control system comprises a heating device, a temperature measuring device and a control device, wherein the heating device heats the measuring component, the temperature measuring device measures the heating temperature of the heating device, and the control device controls the heating device according to the measuring result of the temperature measuring device; the temperature control system generates a stable temperature field, so that the error of the temperature stress on the acceleration measuring device can be reduced.

Furthermore, the PID controller comprises a debugging resistor, a current limiting resistor R5, a debugging capacitor and an operational amplifier; the debugging resistor comprises a resistor R1, a resistor R2, a resistor R3 and a resistor R4, and the debugging capacitor comprises a capacitor C1 and a capacitor C2; the input ends of a resistor R1 and a capacitor C1 are connected with the output end of an instrumentation amplifier, the output end of a resistor R1 is connected with the inverting input end of an operational amplifier, the output end of a capacitor C1 is connected with the input end of a resistor R2, the output end of a resistor R2 is connected with the inverting input end of the operational amplifier, the input end of a capacitor C2 is connected with the inverting input end of the operational amplifier, the output end of a capacitor C2 is connected with the input end of a resistor R4, and the output end of a resistor R4 is connected with; the input end of the resistor R3 is connected with the inverting input end of the operational amplifier, and the output end of the resistor R3 is connected with the output end of the operational amplifier; the input end of the current limiting resistor R5 is connected with the non-inverting input end of the operational amplifier, and the output end of the current limiting resistor R5 is grounded. The PID control differential time constant can be changed by adjusting a resistor R1, a resistor R2, a resistor R3, a resistor R4, a capacitor C1 and a capacitor C2. The selection of a proper differential time constant is beneficial to reducing the overshoot of the system, improving the response speed and reducing the adjustment time.

Furthermore, the metal sleeve and the metal base are hermetically connected to form a sealed space, and the measuring part and the data converting part are arranged in the sealed space. By forming the sealed space, the working temperature of the quartz flexible accelerometer is convenient to control, and errors caused by the temperature to a measuring device are reduced.

Acceleration measurement in three axial directions of XYZ under a traditional Cartesian coordinate system is realized by measuring acceleration under a UVW coordinate and converting the acceleration under the UVW coordinate into acceleration under an XYZ rectangular coordinate system. The special design of the z-axis accelerometer in the traditional quartz flexible accelerometer is avoided, and the z-axis device is not required to be distinguished from the x-axis device and the y-axis device, so that the design difficulty and the processing difficulty of the inertia measurement unit are reduced.

Furthermore, according to a conversion matrix of a UVW coordinate system and an XYZ coordinate system, the matrix coefficient is less than 1, so that the measuring range of the three-axis quartz flexible accelerometer is improved.

Drawings

FIG. 1 is a schematic block diagram of a triaxial quartz flexure accelerometer assembly system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a triaxial quartz flexure accelerometer assembly according to an embodiment of the invention;

FIG. 3 is a schematic diagram of conversion between a UVW coordinate system and an XYZ coordinate system;

FIG. 4 is a block diagram of a temperature control system according to an embodiment of the present invention;

FIG. 5 is a PID controller according to an embodiment of the invention;

fig. 6 is a schematic diagram of pwm and power driving circuits according to an embodiment of the present invention.

In the figure: 1 is a metal sleeve; 2 is a screw; 3 is a quartz flexible accelerometer; 4 is an installation platform; 5 is an electronic component; 6 is a PCB board; 7 is a metal base; and 8 is an outlet end interface.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

The invention relates to a triaxial quartz flexible accelerometer assembly, which comprises a measuring component and a data conversion component, wherein the measuring component is connected with the data conversion component; the measurement component measures acceleration under a UVW coordinate, and the data conversion component converts the acceleration under the UVW coordinate into acceleration under an XYZ rectangular coordinate system.

The measuring component comprises a mounting platform 4 and three quartz flexible accelerometers 3; the mounting platform 4 is in a triangular pyramid shape, the three quartz flexible accelerometers 3 are fixedly arranged on three side surfaces of the mounting platform 4, and the bottom surface of the mounting platform 4 is horizontally arranged; the axes formed by the three quartz flexible accelerometers 3 are mutually vertical, and the included angles between the axes of the three quartz flexible accelerometers 3 along the horizontal plane are equally divided.

The data conversion part comprises an analog-digital conversion unit and an FPGA signal processing unit. The output ends of the three quartz flexible accelerometers are connected with the input end of the analog-to-digital conversion unit, the output end of the analog-to-digital conversion unit is connected with the input end of the FPGA signal processing unit, the output end of the FPGA signal processing unit is connected with a user post-stage digital system, and the user post-stage digital system processes measured acceleration values.

An acceleration measurement method, comprising the process of:

step 1, defining the sensitive axes of three quartz flexible accelerometers 3 as U, V, W coordinate axes respectively, and measuring to obtain the acceleration of a measured object under a UVW coordinate system;

and 2, converting the acceleration under the UVW coordinate system into the acceleration of the measured object under the XYZ coordinate system through a data conversion component, and outputting X, Y, Z three-axial acceleration digital signals under the XYZ coordinate system.

As shown in fig. 3, the transformation matrix between the UVW coordinate system and the XYZ coordinate system is:

wherein β represents the angle between the projection of the V axis on the XY plane and the Y axis, and θ represents the angle between the U, V, W axis and the XY plane. To ensure that each axis of the Galperin coordinate system UVW equally senses gravity and is orthogonal to each other. The UVW triaxial axes are equally spaced in the XY plane, and β is 30 °.

According to the UVW axis direction vector:

whereinThe three are mutually orthogonal, so that theta is approximately equal to 35.26 degrees. Therefore, the inclination angle of three sensitive axes of UVW is 35.26 degrees, namely the included angle of the mounting planes of the three quartz flexible accelerometers and the XY plane is 54.74 degrees, so that the U, V, W three axes are orthogonal to each other.

The invention discloses a triaxial quartz flexible accelerometer assembly, which is characterized in that three quartz flexible accelerometers are arranged in a Galperin three-component configuration mode to measure the acceleration under a UVW coordinate, the acceleration under the UVW coordinate is converted into the acceleration under an XYZ rectangular coordinate system through a data conversion component, and the measurement of the acceleration in three axial directions of XYZ under the traditional Cartesian coordinate system is realized. The three quartz flexible accelerometers in the invention have the same structure and the same external stress, thereby avoiding the special design of the z-axis accelerometer in the traditional high-precision inertial measurement unit and avoiding distinguishing the z-axis device from the x-axis device and the y-axis device, thereby reducing the design difficulty and the processing difficulty of the inertial measurement unit. When the method is applied, the influence of the gravity acceleration of the external environment on a measurement system is not required to be considered, and the design difficulty of a rear-stage inertial navigation system, an inclination measurement system, a vibration measurement system and the like is reduced.