阅读说明：本技术 微型轴转速和角度的测量方法 (Method for measuring rotating speed and angle of micro shaft ) 是由 韩志乐 简小华 于 2020-06-18 设计创作，主要内容包括：本发明涉及微型轴转速和角度的测量方法,其步骤：1)、选择直径相等的转子和被检测轴进行同轴固定,或者直接采用被检测轴替换转子,超声波传感器位于超声回波检测区内；2)、启动旋转传输部分和超声波传感器,在被检测轴和超声波传感器的同步转动下进行超声回波的信号采集；3)、超声波传感器将所采集的反射回波强度向信号处理部分传达,由信号处理部分进行数据分析,其中根据分析结果能够获得被检测轴的转速和转动角度的具体值。本发明由超声波传感器在多个格栅条形成超声回波检测区转动并形成强弱不同的回波信号反馈至信号处理部分进行分析处理,从而得出检测结果,同时,即使被检测轴的外径是1mm以下,也是能够实施准确的检测。(The invention relates to a method for measuring the rotating speed and the angle of a miniature shaft, which comprises the following steps: 1) selecting rotors with the same diameters and detected shafts to be coaxially fixed, or directly replacing the rotors with the detected shafts, wherein the ultrasonic sensors are positioned in the ultrasonic echo detection area; 2) starting the rotary transmission part and the ultrasonic sensor, and acquiring ultrasonic echo signals under the synchronous rotation of the detected shaft and the ultrasonic sensor; 3) and the ultrasonic sensor transmits the acquired reflected echo intensity to the signal processing part, and the signal processing part performs data analysis, wherein specific values of the rotating speed and the rotating angle of the detected shaft can be obtained according to the analysis result. The ultrasonic sensor rotates in the ultrasonic echo detection area formed by the plurality of grid bars and forms echo signals with different strengths to be fed back to the signal processing part for analysis processing, so that the detection result is obtained, and meanwhile, even if the outer diameter of the detected shaft is less than 1mm, accurate detection can be carried out.)

1. A method for measuring the rotating speed and the angle of a miniature shaft is characterized in that: the method adopts an ultrasonic rotary encoder to carry out measurement, the ultrasonic rotary encoder comprises a sensor part, a rotary transmission part and a signal processing part, the sensor part comprises a stator with a circular and straight pipe-shaped section, a rotor which is freely and rotatably arranged in the stator around the central line direction of the stator, an ultrasonic sensor which is fixedly arranged at the end part of the rotor extending into the stator, and a plurality of grid bars which are uniformly distributed around the circumference of the stator, wherein the strength difference exists between an echo signal formed by the grid bars and an echo signal formed by the side wall of the stator, the ultrasonic sensor is positioned in an ultrasonic detection area echo formed by the grid bars,

the method comprises the following measurement steps:

1) selecting rotors with the same diameters and detected shafts to be coaxially fixed, or directly replacing the rotors with the detected shafts, wherein the ultrasonic sensor is positioned in an ultrasonic echo detection area formed by a plurality of grid bars on the stator;

2) starting the rotary transmission part and the ultrasonic sensor, and acquiring signals of ultrasonic echoes under the synchronous rotation of a detected shaft and the ultrasonic sensor, wherein when an emitting surface of the ultrasonic sensor is parallel to a tangent line of each grating strip, a reflected echo signal is strongest and Amax, when the emitting surface of the ultrasonic sensor is over against the middle position of two adjacent grating strips, the reflected echo signal is weakest and is Amin, and when the emitting surface of the ultrasonic sensor is at other positions, the reflected echo signal is between Amax and Amin;

3) and the ultrasonic sensor transmits the collected reflection echo signals to the signal processing part, and the signal processing part performs data analysis, wherein specific values of the rotating speed and the rotating angle of the detected shaft can be obtained according to the analysis result.

2. The method of measuring the rotational speed and angle of a micro-shaft according to claim 1, wherein: in the step 2), the end part of the stator close to the grid bar is arranged in a closed mode, and an ultrasonic transmission medium is filled in the ultrasonic echo detection area during detection.

3. The method of measuring the rotational speed and angle of a micro-shaft according to claim 1, wherein: in step 2), the ultrasonic sensors and the corresponding grid bars form a group of information acquisition units, a plurality of groups of information acquisition units are formed on the stator and the rotor, each group of information acquisition units is provided with one grid bar and other groups of information acquisition units, the grid bars correspond to each other and are arranged on the inner wall of the stator side by side, and the two groups of grid bars of the information acquisition units are adjacent and distributed in a staggered manner relatively.

4. The method of measuring the rotational speed and angle of a micro-shaft according to claim 3, wherein: be formed with from the inside sunken mounting groove in surface on the circumference side of the ultrasonic echo detection zone that the rotor corresponds, the information acquisition unit has three groups, three groups the grid strip sets up side by side the stator inner wall, it is three ultrasonic sensor with grid strip one-to-one and side by side in the mounting groove, wherein the grid strip quantity of first row and second row equals and is N, and has 180/N's angular deviation between the grid strip of first row and second row, the third row grid strip quantity is 1, also is equipped with 180/N's angular deviation between the grid strip of second row and third row.

5. The method of measuring the rotational speed and angle of a micro-shaft according to claim 1, wherein: the detected shaft is the rotor, and the diameter of the detected shaft is greater than or equal to 0.3 mm; the inner diameter of the stator is more than or equal to 0.4mm, and the outer diameter of the stator is more than or equal to 0.5 mm.

6. The method of measuring the rotational speed and angle of a micro-shaft according to claim 1, wherein: the grid strips are embedded, etched or evaporated on the inner wall of the stator.

7. The method of measuring the rotational speed and angle of a micro-shaft according to claim 6, wherein: the inner wall of the stator is provided with a notch groove, and the grid bars are formed in the notch groove.

8. The method of measuring the rotational speed and angle of a micro-shaft according to claim 7, wherein: the side face of the grid strip facing the rotor is flush with the inner wall face of the stator.

9. The method of measuring the rotational speed and angle of a micro-shaft according to claim 8, wherein: the grating bars are made of metal sheets or metal wires, the stator is made of plastics, and echo signals formed by the grating bars are stronger than echo signals formed by the side wall of the stator.

10. The method of measuring the rotational speed and angle of a micro-shaft according to claim 1, wherein: a rotating connection is also provided between the rotor and the stator.

Technical Field

The invention belongs to the field of ultrasonic encoders, and particularly relates to a method for measuring the rotating speed and the angle of a miniature shaft.

Background

At present, a rotary encoder is also called a shaft encoder, and is a device that mainly converts a rotational position or a rotational amount into an electronic signal, and is applicable to industrial control, robotics, a dedicated lens, and the like.

The rotary encoder is mainly divided into an absolute encoder and an incremental encoder, wherein the incremental encoder calculates the rotating speed and the relative position by using a pulse detection mode and can output information related to rotary motion; an absolute type encoder will output the absolute position of the rotating shaft, which can be considered as an angle sensor.

The operation modes of the encoder are generally divided into a mechanical type, an optical type, an electromagnetic type, an induction type, a capacitance type and the like, the sensors combine a detection element and a processing circuit together, the structure is large, the diameter is generally more than 15mm, and the encoder cannot be well applied to the fields with narrow structures.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a brand-new method for measuring the rotating speed and the angle of the micro shaft.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for measuring the rotation speed and angle of miniature shaft features that an ultrasonic rotary encoder is used for measuring the rotation speed and angle of miniature shaft, and includes a sensor unit consisting of a stator with circular and straight tube-shaped cross section, a rotor in the stator, an ultrasonic sensor fixed to the end of rotor, and multiple grating bars uniformly distributed around the stator, and a signal processing unit consisting of a signal generator, a signal processing unit, and a signal processing unit,

the method comprises the following measurement steps:

1) selecting rotors with the same diameters and detected shafts to be coaxially fixed, or directly replacing the rotors with the detected shafts, wherein the ultrasonic sensor is positioned in an ultrasonic echo detection area formed by a plurality of grid bars on the stator;

2) starting the rotary transmission part and the ultrasonic sensor, and acquiring signals of ultrasonic echoes under the synchronous rotation of a detected shaft and the ultrasonic sensor, wherein when the transmitting surface of the ultrasonic sensor is parallel to the tangent line of each grating strip, the reflected echo intensity is maximum Amax, when the transmitting surface of the ultrasonic sensor is over against the middle position of two adjacent grating strips, the reflected echo intensity is minimum Amin, and when the transmitting surface of the ultrasonic sensor is at other positions, the reflected echo intensity is between Amax and Amin;

3) and the ultrasonic sensor transmits the acquired reflected echo intensity to the signal processing part, and the signal processing part performs data analysis, wherein specific values of the rotating speed and the rotating angle of the detected shaft can be obtained according to the analysis result.

Preferably, in step 2), the stator is arranged close to the end of the grid bar, and an ultrasonic transmission medium is filled in the ultrasonic echo detection area during detection. After the end part of the stator is closed, a transmission medium, such as water, a saline water mixture and other media can be filled in an ultrasonic echo detection area formed by the stator, and further the ultrasonic wave can be smoothly transmitted between the ultrasonic sensor and the grating strip, and between the ultrasonic sensor and the inner wall of the stator.

According to a specific implementation and preferred aspect of the present invention, in step 2), the ultrasonic sensors and the corresponding grid bars form a set of information acquisition units, a plurality of sets of information acquisition units are formed on the stator and the rotor, and a plurality of ultrasonic sensors are arranged in parallel in the mounting groove, wherein each set of grid bars is arranged correspondingly and side by side on the inner wall of the stator, one set of information acquisition units in the plurality of sets has one grid bar, and two sets of grid bars of two adjacent sets of information acquisition units in other sets of information acquisition units are distributed in a relatively staggered manner. Through the synchronous motion of the information acquisition units of multiple groups and the acquisition of information, namely multi-bit gray coding, namely an absolute encoder, the number of bits of the gray coding is improved by increasing the number of rows of the grid strips and the number of the ultrasonic sensors, so that the resolution of the encoder is improved, and the detection result is more accurate.

Preferably, the information acquisition unit has three groups, three groups of grid bars are arranged on the inner wall of the stator side by side, wherein the number of the grid bars in the first row and the second row is equal to N, an angle deviation of 180 degrees/N is formed between the grid bars in the first row and the second row, the number of the grid bars in the third row is 1, and an angle deviation of 180 degrees/N is also formed between the grid bars in the second row and the third row.

Preferably, the detected shaft is a rotor and has a diameter greater than or equal to 0.3 mm; the inner diameter of the stator is more than or equal to 0.4mm, and the outer diameter of the stator is more than or equal to 0.5 mm. Thus, in this example, the rotation speed and rotation angle of the upper shaft having a diameter of 0.3mm or more can be detected.

According to a further embodiment and preferred aspect of the invention, the grid bars are embedded, etched or evaporated on the inner wall of the stator. Of course, the outer wall also works, and the advantage of the grille strips arranged on the inner wall is that: the ultrasonic echo can be reflected more accurately, and the detection precision is improved.

Preferably, the stator has a notch formed in an inner wall thereof, and the grill bars are formed in the notch.

Specifically, the side of the grid bar facing the rotor is flush with the inner wall surface of the stator. Therefore, the forming of the grid bars is very convenient, the ultrasonic echo detection is more accurately realized, and the appearance is more attractive.

Preferably, the grid bars are made of metal sheets or metal wires, and the stator is made of plastic. The echo intensity formed between the metal and the plastic is greatly different, so that the acquisition of a detection signal is facilitated, namely, the echo signal formed by the grating bars is stronger than the echo signal formed by the side wall of the stator.

Furthermore, a rotary connection is provided between the rotor and the stator. Certainly, the rotating connecting piece is not arranged and is not influenced, and after the rotating connecting piece is arranged, the rotor rotates more stably relative to the stator.

Due to the implementation of the technical scheme, compared with the prior art, the invention has the following advantages:

the invention utilizes the synchronous rotation of the ultrasonic sensor and the detected shaft, the ultrasonic sensor rotates in the ultrasonic echo detection area formed by a plurality of grating strips and forms echo signals with different strengths to be fed back to the signal processing part for analysis processing, thereby obtaining the detection result, meanwhile, even if the outer diameter of the detected shaft is less than 1mm, the invention can also carry out accurate detection ultrasonic detection compared with other parts, has the following advantages that the transmission of ultrasonic has no requirements on light, electromagnetism and the like, is not easily influenced by external conditions, and is suitable for the detection of lightproof materials.

Drawings

FIG. 1 is a schematic structural view of an ultrasonic rotary encoder of the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1;

FIG. 3 is an enlarged schematic view of the echo intensity at the ultrasonic sensor of FIG. 1;

FIG. 4 is a schematic view of the structure of an ultrasonic rotary encoder of the present invention (absolute type encoder);

FIG. 5 is a graph of echo intensity values Ai and time corresponding information for an ultrasonic sensor;

FIG. 6 is a graph of the motion after being processed and analyzed by the signal processing section according to the graph of FIG. 5;

FIG. 7 is a motion curve of three rows of scale acquisition information after being processed and analyzed by the signal processing section;

wherein: 1. a sensor portion; 10. a stator; 100. grooving; 11. a rotor; 110. mounting grooves; 12. an ultrasonic sensor; 13. grid bars; 14. rotating the connecting piece; 15. a cable;

2. a rotation transmitting portion; 20. a rotating part; 21. an information transmission unit;

3. and a signal processing section.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise explicitly specified or limited, a first feature "on" or "under" a second feature may be directly contacted with the first and second features, or indirectly contacted with the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

As shown in FIG. 1, the method for measuring the rotation speed and angle of the micro-shaft disclosed in this embodiment uses an ultrasonic rotary encoder for detection.

Specifically, the ultrasonic rotary encoder comprises a sensor part 1, a rotation transmission part 2 (which can be a slip ring, a rotary transformer, a rotary capacitor, a rotary optical fiber coupler, etc.), and a signal processing part 3, wherein the rotation transmission part 2 comprises a rotating part 20 for driving a detected shaft to rotate around the axis direction of the rotation transmission part, and an information transmission part 21 communicated with the sensor part 1 and the signal processing part 3, detection information obtained by the sensor part 1 is transmitted to the signal processing part 3 by the information transmission part 21, and the signal processing part 3 performs signal analysis to obtain measurement information.

The sensor section 1 includes a stator 10 having a circular cross section and a straight tube shape, a rotor 11 rotatably provided inside the stator 10 around the center line direction of the stator 10, an ultrasonic sensor 12 fixedly provided at an end of the rotor 11 extending into the stator 10, and a plurality of grid bars 13 uniformly distributed around the circumference of the stator 10.

In this example, the outer diameter of the stator 10 is 1.0mm, the inner diameter of the stator is 0.8-0.9mm, and the outer diameter of the rotor 11 is 0.6 mm.

The detected shaft is the rotor 11, and the rotor 11 and the stator 10 are coaxially and rotationally connected through a rotational connecting piece 14.

In this example, each of the grating bars 13 is a tungsten wire disposed on the inner wall of the stator 10, and the ultrasonic sensor 12 is located in an ultrasonic echo detection region formed by the plurality of grating bars 13.

Referring to fig. 2, a notch 100 is formed in the inner wall of the stator 10, a grid bar 13 is formed in the notch 100, and the side surface of the grid bar 13 facing the rotor 11 is flush with the inner wall surface of the stator 10. The forming of grid bars is very convenient, and the ultrasonic echo detection is more accurately realized.

Simultaneously, the material of stator 10 is plastics, and the closed setting of tip that stator 10 is close to grid strip 13, so, after the closed of stator 10 tip, can be full of transmission medium in the supersound echo detection zone that stator 10 formed, medium such as water, salt water mixture, and then guarantee that the ultrasonic wave can be smooth propagate between ultrasonic sensor and grid strip, ultrasonic sensor and stator inner wall.

An inwardly recessed mounting groove 110 is formed on a circumferential side surface of the rotor 11 that protrudes into an end portion of the stator 10, and the ultrasonic sensor 12 is disposed in the mounting groove 110.

The mounting groove 110 extends along the length direction of the rotor 11, and the ultrasonic sensor 12 and the corresponding grating strip 13 constitute a set of information acquisition units H.

The rotor 11 is provided hollow inside, and the sensor portion 1 further includes a cable 15 located inside the rotor 11 and capable of communicating the ultrasonic sensor 12 with the rotation transmission portion 2. Of course, the ultrasonic sensor 12 may feed back the obtained information to the information transmission unit 21 by wireless, and the information is forwarded to the signal processing unit 3 by the information transmission unit 21.

In this example, the length, width, and height of the ultrasonic sensor 12 are 0.4mm 0.5mm 0.3 mm.

In conjunction with fig. 3, during the rotation of the ultrasonic sensor 12, according to the principle of acoustic reflection, when the emitting surface of the ultrasonic sensor 12 is parallel to the tangent of each grating strip 13, the reflected echo intensity is maximum Amax, and at the middle position between two adjacent grating strips 13, the reflected echo intensity is weakest Amin, and when at other positions, the reflected echo intensity is between Amax and Amin.

Referring to fig. 4, three sets of information acquiring units H are formed on the stator 10 and the rotor 11, three ultrasonic sensors 12 are arranged in the mounting groove 110 side by side, three sets of grid bars 13 are arranged on the inner wall of the stator 10 side by side, wherein the number of the grid bars 13 in the first row and the second row is equal to N, an angle deviation of 180 °/N is formed between the grid bars 13 in the first row and the second row, and the number of the grid bars 13 in the third row is 1.

At the same time, the same angular deviation (angle of 180 °/N) also exists between the grid bars 13 of the third row and the grid bars 13 of the second row.

Therefore, three sets of information acquisition units are set, namely 3-bit gray coding, namely absolute type coder.

Also, the number of gray-coded bits can be increased by increasing the number of scale lines and the number of ultrasonic sensors, thereby increasing the resolution of the encoder.

In addition, taking an ultrasonic probe with a center frequency of 50MHz as an example, the transverse resolution of the ultrasonic probe is about 200um, and the size of the resolution determines that the minimum scale interval of the grating bars on the stator cannot be smaller than the transverse resolution of the ultrasonic probe, so that the required strong and weak signals can be acquired

Assuming a lateral resolution of λ, the angular resolution of the encoder is up to 360 °/λ. We can improve the accuracy of the encoder by increasing the number of sensors.

In summary, in the embodiment, the sensor is designed by using the intensity of the reflected echoes of different reflectors when the ultrasonic waves encounter, and the rotation speed and the position of the rotating object are measured by using the principle of rotation coding.

Meanwhile, the ultrahigh frequency miniature ultrasonic sensor can be used for designing the structure of the encoder to be used for measuring the rotating speed and the position of a detected shaft with the diameter of more than 0.3mm, so that the ultrahigh frequency miniature ultrasonic sensor can be applied to the field of high-precision detection, such as in-vivo interventional medical imaging equipment, can effectively correct image distortion (NURD) and the like caused by rotational distortion, ensures the accuracy of images and has very good advantages.

The detection process of this embodiment is as follows:

1) replacing the rotor with the detected shaft, forming a mounting groove at the end part of the rotor, and correspondingly distributing the ultrasonic sensors in the mounting groove and correspondingly positioning the ultrasonic sensors in an ultrasonic echo detection area formed by a plurality of grid bars;

2) starting the rotary transmission part and the ultrasonic sensor, and acquiring signals of ultrasonic echoes under the synchronous rotation of a detected shaft and the ultrasonic sensor, wherein when the transmitting surface of the ultrasonic sensor is parallel to the tangent line of each grating strip, the intensity of the reflected echo is strongest and is Amax, when the transmitting surface of the ultrasonic sensor is over against the middle position of two adjacent grating strips, the intensity of the reflected echo is weakest and is Amin, and when the transmitting surface of the ultrasonic sensor is at other positions, the intensity of the reflected echo is between Amax and Amin;

3) and the ultrasonic sensor transmits the acquired reflected echo intensity to the signal processing part, and the signal processing part performs data analysis, wherein specific values of the rotating speed and the rotating angle of the detected shaft can be obtained according to the analysis result. .

Meanwhile, in order to further improve the resolution of the encoder, in step 1), three groups of information acquisition units may be arranged side by side to form a three-bit gray code, and of course, multiple groups of multi-bit gray codes may be used for detection, so that the motion data of the detected shaft can be acquired more accurately.

Specifically, in this example, the grid bars uniformly distributed on the circumference of the stator form n scales, so the angle between each reflection scale is θ =360 °/n, during the rotation of the ultrasonic sensor, the ultrasonic sensor continuously transmits and receives ultrasonic signals, and assuming that the number of transmitted signals per rotation is m, the value needs to be much larger than n (because if only n signals are received per rotation of the rotor, that is, each grid bar only receives one echo signal, so that data sampling is far insufficient, and therefore enough m transmitted signals exist, so that the amplitude of the received back signal can be guaranteed, and each position and the adjacent position are almost continuously changed).

The value of each received echo intensity of the sensor is set to Ai,

the strength values of the echoes received in each turn of the ultrasonic sensor are respectively as follows:

A1,A2,……Ai,……Am。

since the value of m set by the user is far greater than n, it can be assumed that the intensity of n scale reflected echoes is the maximum, the signal Amax, the intensity of n reflected echoes is the minimum, and the signal Amin are all assumed in each circle.

The signal processing section calculates the intensity Ai of the reflected signal and the echo intensity value Ai versus time t can be plotted as shown in fig. 5. The curve shown in fig. 6 can be obtained by processing of the signal processing part.

Similarly, if three sets of information acquiring units are used, wherein the angle deviation of θ/2 is formed between the scales formed by the first and second rows, and the scale of the third row has only one scale, the information obtained by each set of information acquiring units is transmitted to the signal processor, so as to obtain the curve shown in fig. 7.

The present invention has been described in detail in order to enable those skilled in the art to understand the invention and to practice it, and it is not intended to limit the scope of the invention, and all equivalent changes and modifications made according to the spirit of the present invention should be covered by the present invention.