CN101266146A - Inclination angle measuring device with automatic zero position compensation - Google Patents

Abstract

The invention discloses an inclination angle measuring device, which comprises a base, a rotating disk, an inclination angle sensor, an A/D converter, a motor, a microprocessor and a digital output interface, a first inclination angle sensor and a second inclination angle sensor The sensor is fixed on the edge of the rotating disk, the sensitive axes of the two are perpendicular to each other, and the phase difference is 90°. After the inclination angle measuring device is started, it first reads the first output voltage value of the first inclination angle sensor at the first position, and then uses Rotate the rotating disk by 90°, after a certain period of time delay, read the second output voltage value of the second sensor at the second position, calculate the zero deviation angle between the measurement reference plane and the plane where the rotating disk is located, and then The rotating disk is rotated 90° in the opposite direction, and the formal measurement is carried out after a certain period of time delay again. The tilt angle measuring device provided by the invention is easy to use and can complete zero position compensation without a standard horizontal workbench.

Description

Inclination angle measuring device with automatic zero position compensation

technical field

The present invention relates to an inclination angle measuring device, more particularly, the present invention relates to an inclination angle measuring device with an automatic compensation function, which can be formed due to assembly and other reasons without the need for a standard horizontal workbench The zero position deviation is automatically compensated.

Background technique

In engineering fields such as machinery, construction, automobile, petroleum, geology and electric power, it is often required to accurately measure the inclination angle of the plane relative to the horizontal direction to provide control parameters for state monitoring or attitude control.

Chinese patent applications with publication numbers CN1003344A, CN1013063A, CN1320808A and CN1668892A respectively disclose inclination angle measuring devices based on "liquid pendulum". The basic principle is that the measuring device includes two measuring electrodes and a common electrode, the electrodes are placed in a closed chamber, and the chamber is filled with high dielectric constant liquid and gas. When the measuring device is in the horizontal position, the two electrodes have equal areas immersed in the dielectric liquid, and two equal capacitors are formed by the electrodes and the open electrodes; when the inclinometer rotates an angle, the two electrodes are immersed in the liquid The areas are not equal, and the resulting capacitance difference represents the measured inclination angle.

The Chinese patent application with publication number CN1532523A discloses a digital level and angle measuring instrument based on a "solid pendulum", which includes a housing and an angle measuring device, the angle measuring device is a capacitance angle measuring sensor, and the housing and the capacitance angle measuring instrument The main grid or auxiliary grid is fixedly connected, and there is also a gravity vertical device in the inner cavity of the shell that always automatically returns and remains in the gravity vertical state. The gravity vertical device is fixedly connected with the auxiliary grid or main grid of the capacitance angle measuring instrument and rotates coaxially ; There is also a precision position switch for determining the absolute zero position on the shell. The gravity vertical device is composed of a weight, a supporting shaft and a buoy. The position and shape of the buoy are symmetrical along the vertical axis of the weight. In addition, the Chinese patent applications with the notification numbers CN2492832Y, CN2530245Y, CN2624179Y and CN2684149Y respectively disclose different structures of tilt angle measuring devices based on "solid pendulum". parameter changes to obtain measurement results.

The Chinese patent applications whose notification numbers are CN2335125Y, CN2505806Y, CN2509562Y, CN2575607Y, CN2622676Y, CN2760507Y and CN2738204Y respectively disclose inclination angle measuring instruments or meters integrated with different types of sensors. Peripheral circuits can visually display the measurement results.

However, none of the above-mentioned prior art relates to how to automatically compensate the zero position deviation of the measuring device. As we all know, during the assembly process of various measuring devices, it is difficult to ensure that the measuring surface of the measuring device is absolutely parallel to the sensitive axis of the sensor, that is, there is a certain zero position deviation. Therefore, measuring devices must be calibrated before use to compensate for zero offset. The usual method of compensating for zero position deviation in the prior art is to place the assembled measuring device on a standard horizontal workbench, measure its output result, and then either adjust the position of the sensor or compensate the output value to eliminate Zero offset. This process is complicated to operate, and the efficiency is low, so it is not suitable for mass production.

Contents of the invention

The present invention aims to provide an inclination angle measuring device with automatic compensation function, which can automatically compensate the zero position deviation caused by assembly and other reasons without a standard horizontal workbench.

To achieve the above object, the present invention provides a kind of inclination angle measurement device, it comprises base, rotating disk, inclination angle sensor, A/D converter, motor, microprocessor and digital output interface, wherein has on the base To measure the reference plane, the A/D converter collects the output voltage of the inclination sensor, and sends the result to the microprocessor. The inclination angle between them, the first inclination sensor is installed at the edge of the rotating disk, the second inclination sensor is installed at the position where the first inclination sensor is rotated 90° around the central rotation axis of the rotating disk, and the second inclination The sensitive axes of the sensor and the first inclination sensor are perpendicular to each other. The rotating disk is fixed on the output shaft of the motor and can rotate at least 90° around the output shaft of the motor. After the inclination angle measuring device is started, it first reads the first The first output voltage value of the inclination angle sensor, and then the microprocessor controls the motor to rotate, so that the rotating disc rotates 90°, after a certain period of time delay, read the second output voltage value of the second sensor at the second position, according to the first The difference between the first output voltage value and the second output voltage value is used to calculate the zero deviation angle between the measurement reference plane and the plane where the rotating disk is located, and then the rotating disk is rotated in the opposite direction by 90°, and after a certain period of time is delayed again. formal measurement.

The present invention also provides a method for automatic zero position compensation of an inclination angle measuring device, wherein the inclination angle measuring device includes a base, a rotating disc, an inclination angle sensor, an A/D converter, a stepping motor, a micro Processor and digital output interface, there is a measurement reference surface on the base, the A/D converter collects the output voltage of the inclination angle sensor, and sends the result to the microprocessor, and the microprocessor based on a specific functional relationship according to the inclination angle sensor Calculate the inclination angle between the measurement reference plane and the horizontal plane with the output voltage, the first inclination sensor is installed on the edge of the rotating disk, and the second inclination sensor is installed on the center rotation axis of the first inclination sensor to rotate 90 °, and the sensitive axes of the second inclination sensor and the first inclination sensor are perpendicular to each other, the rotating disk is fixed on the output shaft of the stepper motor, and can rotate at least 90° around the output shaft of the stepper motor, The method comprises the steps of:

reading the first output voltage value of the first tilt angle sensor at the first position;

The microprocessor controls the stepper motor to rotate the rotating disc by 90°;

Delay for a certain period of time;

reading the second output voltage value of the second tilt angle sensor at the second position;

Calculate the zero deviation angle between the measurement reference plane and the plane where the rotating disk is located according to the difference between the first output voltage value and the second output voltage value;

Rotate the rotating disc 90° in the opposite direction;

Delay again for a certain period of time;

Entering the formal measurement, during the measurement process, the zero deviation angle will be subtracted from the angle calculated based on the output voltage of the inclination angle sensor based on a specific functional relationship.

The tilt angle measuring device provided by the invention is easy to use and can complete zero position compensation without a standard horizontal workbench.

Description of drawings

The present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments. in:

Figure 1 shows a schematic diagram of the structure of a capacitive tilt angle sensor based on a "solid pendulum";

The schematic diagram shown in Figure 2 shows the relationship between the output electrical signal Vo and the tilt angle φ;

The schematic diagram shown in Figure 3 shows the principle of zero offset compensation according to the present invention;

The schematic diagram shown in Figure 4 further illustrates the principle of zero offset compensation according to the present invention;

Fig. 5 shows the block diagram of the overall structure according to the inclination angle measuring device of the present invention;

Figure 6 shows the flow chart of the entire system work.

The schematic diagram shown in Figure 7 is the situation when the disc is at the first position when two sensors are installed;

The schematic diagram shown in Figure 8 is the situation where the disk is at the second position when two sensors are installed;

Figure 9 is a flow chart showing how the entire system works when two sensors are installed.

Detailed ways

Figure 1 shows a schematic diagram of the structure of a capacitive tilt angle sensor based on a "solid pendulum". The inclination angle sensor in Figure 1 measures the inclination angle by sensing the earth’s gravitational vector passing through the axis of the object. It includes a cantilever beam fixed on the shell, and a movable plate is connected to the cantilever beam. The movable plate is located on two fixed between the plates. For the convenience of illustration, the cantilever beam in Figure 1 is simplified as an elastic system with certain damping. The gravity of the object m causes the deformation of the cantilever beam. For different inclination angles, there is a corresponding amount of deformation of the cantilever beam. As the cantilever beam deforms under the action of gravity, the movable plate moves between the two fixed plates accordingly, and the change in the position of the movable plate will cause the change of the capacitance between the plates. Capacitance, you can know the size of the tilt angle. It should be pointed out that although the present invention is described based on the capacitive inclination angle sensor based on "solid pendulum" here, those skilled in the art can understand that the present invention is equally applicable to sensors based on "liquid pendulum" or "gas pendulum" and Measuring devices for other technologies.

As shown in Figure 1, when the inclination angle is φ, the axial force formed under the gravity of the object m is F=mgsinφ, and the force causes the end of the cantilever beam to generate a displacement x:

$\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; mg</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

where k is the elastic strength. The following formula can be used to convert the displacement x into a voltage output:

$\mathrm{<span\; class="notranslate">\; Vp</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}{\mathrm{<span\; class="notranslate">\; k</span>}}\mathrm{<span\; class="notranslate">\; mg</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, Kp represents the proportional coefficient between the voltage obtained by detecting the capacitance change and the displacement x. The final output result Vo after the gain amplifier is:

$\mathrm{<span\; class="notranslate">\; Vo</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}}{\mathrm{<span\; class="notranslate">\; k</span>}}\mathrm{<span\; class="notranslate">\; mg</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&phi;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

The schematic diagram shown in FIG. 2 shows the relationship between the output electrical signal Vo and the tilt angle φ.

When carpenters and construction workers measure whether the plane is level, they usually use a bubble level to measure. The specific method is to first place the bubble level on the measured plane and record the position of the bubble in the positive direction. However, rotate the level 180° and observe the position of the blister in the opposite direction. If the position of the water bubble is the same during the two measurements, it means that the measured plane is in a horizontal state, otherwise, there is a deviation. The schematic diagram shown in Fig. 3 shows the zero offset compensation process according to the present invention; in this application, it is assumed that the sensitive axis of the sensor is OA, and another axis perpendicular to the sensitive axis OA in the horizontal plane is IA. The zero compensation process of the inclination angle measuring device of the present invention will be described in detail below.

First, the inclination sensor is placed on a rotating disc whose surface is parallel to the measuring plane formed by the axes OA and IA of the sensor. At the first position POSITION 1, record the output voltage of the sensor, however, rotate the disc 180°, again record the output voltage of the sensor at the second position POSITION 2. If the rotating disc is horizontal, the output voltage of the sensor will be the same in the first position and in the second position. If there is a certain angle φ between the plane where the rotating disk is located and the horizontal plane, the output voltage of the sensor at the above two positions will be different, and the difference between the output voltages is a function of the angle φ. relationship is described in detail.

When the rotating disk is in a horizontal state, the output voltage value of the sensor should be zero in theory. But actually the sensor still has a small output voltage V _B , which can be defined as the output voltage independent of the position of the inclination angle sensor. If the rotating disk in Figure 3 is in a horizontal state, it is obvious that the output voltage of the tilt angle sensor in the two positions is:

V ₁ =V ₂ =V _B (4)

The schematic diagram shown in FIG. 4 illustrates the principle of zero offset compensation according to the present invention. Assuming that the reference plane of the measuring device is in a horizontal state, if there is a zero deviation angle φ between the rotating disc in the X-axis direction and the reference plane of the measuring device due to the assembly process, then at the first position and the second position The voltage outputs are:

V ₁ =V _B +V _φ (5)

V ₂ =V _B -V _φ (6)

Among them, V _φ is the output voltage when the angle between the sensor and the horizontal plane is φ, and the formula (5) is subtracted from the formula (6):

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="V"\; filenames="A20071008651000161.png"\; state="\{\{state\}\}">V</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

It can be seen from equation (7) that by measuring the output voltage of the sensor at the first position and the second position, the output voltage V _φ corresponding to the zero position deviation angle can be obtained, which can be easily reversed by formula (3) Calculate the zero position deviation angle φ, so as to complete the zero position compensation. In the actual application process, the following basic conditions must be met:

• The rotating disks in the first and second positions are in the same plane.

·During zero compensation, avoid vibration of the measuring device as much as possible.

·Because the sensor has a certain response time, before reading the output voltage of the sensor, the rotating disk should be kept at the first position and the second position for a certain period of time, so that the output of the sensor can reach a balanced state.

Fig. 5 is a block diagram showing the overall structure of the inclination angle measuring device according to the present invention. The inclination angle measuring device of the present invention selects a stepper motor that is easy to be precisely controlled to realize the rotation of the rotating disc. Mount the tilt sensor precisely on the edge of the rotating disc. The sensor output voltage at the first position and the second position with a phase difference of 180° is collected through the A/D converter, the microprocessor processes the collected data, and after zero compensation is completed, the measurement is output through RS-232 or other interfaces The slope angle value of the face.

Figure 6 shows the flow chart of the entire system work. After the inclination angle measuring device is powered on, the microprocessor first initializes the stepping motor, the A/D converter, the input interface and the output interface. After reading the output voltage value V ₁ of the sensor at the first position, the microprocessor controls the stepper motor to rotate the rotating disc by 180°. After a certain period of time delay (for example, 0.1-5 seconds), the output voltage value V ₂ of the sensor at the second position is read. Then calculate the voltage V _φ , and calculate the zero deviation angle φ according to this voltage. Then the rotating disc is reversely rotated by 180°, and after a certain period of time delay (for example, 0.1-5 seconds), the normal measurement subroutine is entered. During the measurement process, the real inclination angle value of the measurement surface can be obtained by subtracting the zero deviation angle φ from the angle value obtained in real-time measurement.

For the above-mentioned measuring device and method, the disk needs to be rotated by 180° during automatic zero compensation. In order to further simplify the structure of the measuring device, an inclination sensor can be added so that the measuring device only needs to rotate 90° when the measuring device performs zero position compensation, as described below.

As shown in Fig. 7, the disc is in the initial first position. At two places at the edge of the map plate at a distance of 90°, an inclination sensor 1 and an inclination sensor 2 are respectively installed, and their sensitive axes are OA1 and OA2 respectively, and the axis perpendicular to the sensitive axes OA1 and OA2 in the same plane is IA1 and IA2. When installing, make OA1 perpendicular to OA2 through the positioning device.

When the disc rotates by 90°, as shown in FIG. 8 , when the disc is in the second position, the sensitive axis OA1 of the sensor 1 coincides with the sensitive axis OA2 of the sensor 2 in the first position, with the same direction. The sensitive axis OA2 of the sensor 2 coincides with the sensitive axis OA1 of the sensor 1 in the first position, but in the opposite direction. It can be seen from this that if the output characteristics of sensor 1 and sensor 2 are the same, and the sensitive axis OA1 is perpendicular to OA2, then the sensor 2 in the second position is equivalent to the sensor 1 rotating 180° in the X-Y plane. According to the above analysis, A method for automatic zero compensation is available.

Figure 9 is a flow chart showing how the entire system works when two sensors are installed. The microprocessor first initializes the stepper motor, A/D converter, input interface and output interface. After reading the output voltage values V ₁₁ and V ₂₁ of sensor 1 and sensor 2 at the first position, the microprocessor controls the stepping motor to rotate the rotating disc by 90°. After a certain period of delay (for example, 0.1-5 seconds), read the output voltage values V ₁₂ and V ₂₂ of the sensor 1 and the sensor 2 at the second position. Then calculate the voltage V _φ according to formula (8):

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; two</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

And calculate the zero deviation angle φ according to this voltage. Then the rotating disc is reversely rotated by 90°, and after a certain period of time delay (for example, 0.1-5 seconds), the normal measurement subroutine is entered. During the measurement process, the real inclination angle value of the measurement surface can be obtained by subtracting the zero deviation angle φ from the angle value obtained in real-time measurement.

Claims (4)

1. incline measurement device, it comprises pedestal, rotating circular disk, slant angle sensor, A/D converter, motor, microprocessor and digital output interface, wherein has the measuring basis face on the pedestal, A/D converter is gathered the output voltage of slant angle sensor, and its result is delivered to microprocessor, microprocessor calculates pitch angle between measuring basis face and the surface level based on specific funtcional relationship according to the output voltage of slant angle sensor, it is characterized in that:

First obliquity sensor is installed on rotation diagram plate edge place, second obliquity sensor be installed on first obliquity sensor around the centre rotational axis line half-twist of rotating circular disk after residing position, and the sensitive axes of second obliquity sensor and first obliquity sensor is vertical mutually, rotating circular disk is fixed on the output shaft of motor, can rotate at least 90 ° around the output shaft of motor, after starting, at first reads in the incline measurement device first output voltage values of primary importance place first slant angle sensor, microprocessor control motor rotates then, make the rotating circular disk half-twist, delay time after certain period, read second output voltage values of second place place second sensor, calculate zero drift angle between measuring basis face and the plane, rotating circular disk place according to the difference of first output voltage values and second output voltage values, after this with 90 ° of rotating circular disk reverse rotations, formally measure after certain period of delaying time once more.

2. incline measurement device as claimed in claim 1 is characterized in that: described slant angle sensor is the condenser type slant angle sensor based on " solid pendulum ".

3. incline measurement device as claimed in claim 1 or 2 is characterized in that: described motor is a stepper motor.

4. method of the incline measurement device being carried out automatic zero compensation, wherein said incline measurement device comprises pedestal, rotating circular disk, slant angle sensor, A/D converter, stepper motor, microprocessor and digital output interface, has the measuring basis face on the pedestal, A/D converter is gathered the output voltage of slant angle sensor, and its result is delivered to microprocessor, microprocessor calculates pitch angle between measuring basis face and the surface level based on specific funtcional relationship according to the output voltage of slant angle sensor, first obliquity sensor is installed on rotation diagram plate edge place, second obliquity sensor be installed on first obliquity sensor around the centre rotational axis line half-twist of rotating circular disk after residing position, and the sensitive axes of second obliquity sensor and first obliquity sensor is vertical mutually, rotating circular disk is fixed on the output shaft of stepper motor, can rotate at least 90 ° around the output shaft of stepper motor, described method comprises the steps:

Read first output voltage values of primary importance place first slant angle sensor;

Microprocessor control step motor makes the rotating circular disk half-twist;

Delay time certain period;

Read second output voltage values of second place place second slant angle sensor;

Calculate zero drift angle between measuring basis face and the plane, rotating circular disk place according to the difference of first output voltage values and second output voltage values;

With 90 ° of rotating circular disk reverse rotations;

Delay time once more certain period;

Enter formal measurement, in measuring process, will deduct the zero drift angle according to the angle that the output voltage of slant angle sensor calculates based on specific funtcional relationship.

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