阅读说明：本技术 适用于微型轴旋转测量的超声旋转编码器 (Ultrasonic rotary encoder suitable for micro-shaft rotation measurement ) 是由 韩志乐 简小华 于 2020-06-18 设计创作，主要内容包括：本发明涉及适用于微型轴旋转测量的超声旋转编码器,其包括传感器部分、旋转传输部分、信号处理部分,其中传感器部分包括截面呈圆形且呈直管状的定子、转子、固定设置在转子伸入定子端部的超声波传感器、以及绕着定子的周向均匀分布的多个栅格条,其中转子为被检测轴或者转子与被检测轴同轴固定连接,栅格条和定子侧壁所形成的回波信号之间存在强弱差异,超声波传感器位于多个栅格条形成的超声回波检测区内。本发明由超声波传感器在超声回波检测区内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 an ultrasonic rotary encoder suitable for micro-shaft rotation measurement, which comprises a sensor part, a rotation transmission part and a signal processing part, wherein the sensor part comprises a stator with a circular and straight-tube-shaped section, a rotor, an ultrasonic sensor fixedly arranged at the end part of the rotor extending into the stator, and a plurality of grid strips uniformly distributed around the circumference of the stator, wherein the rotor is a detected shaft or the rotor is coaxially and fixedly connected with the detected shaft, echo signals formed by the grid strips and the side wall of the stator have intensity difference, and the ultrasonic sensor is positioned in an ultrasonic echo detection area formed by the grid strips. The ultrasonic sensor rotates in the ultrasonic echo detection area and forms echo signals with different strengths to be fed back to the signal processing part for analysis processing, so that a detection result is obtained, and meanwhile, accurate detection can be carried out even if the outer diameter of a detected shaft is less than 1 mm.)

1. An ultrasonic rotary encoder suitable for micro-shaft rotation measurement comprises a sensor part,

The rotation transmission part comprises a rotation part for driving a detected shaft to rotate around the axis direction of the detected shaft, and an information transmission part communicated with the sensor part and the signal processing part, detection information obtained by the sensor part is transmitted to the signal processing part by the information transmission part, and the signal processing part carries out signal analysis to obtain measurement information, and is characterized in that:

the sensor part includes that the cross-section is circular and is the stator of straight tube form, round the central line direction free rotation ground of stator sets up inside rotor of stator, fixed setting are in the rotor stretches into the ultrasonic sensor of stator tip and round a plurality of grid strips of the circumference evenly distributed of stator, wherein the rotor does the detected shaft or the rotor with be detected the coaxial fixed connection of shaft, the grid strip with there is the difference of power between the echo signal that the stator lateral wall formed, ultrasonic sensor is located a plurality ofly in the supersound echo detection zone that the grid strip formed.

2. An ultrasonic rotary encoder adapted for miniature shaft rotation measurements as set forth in claim 1 wherein: the grid bars are embedded, etched or evaporated on the inner wall of the stator.

3. An ultrasonic rotary encoder adapted for miniature shaft rotation measurements as set forth in claim 2 wherein: the inner wall of the stator is provided with a notch groove, the grid bars are formed in the notch groove, and the side face, facing the rotor, of each grid bar is flush with the inner wall face of the stator.

4. An ultrasonic rotary encoder adapted for miniature shaft rotation measurements as set forth in claim 3 wherein: the material of grid strip is sheetmetal or wire, the material of stator is plastics, wherein the echo signal that grid strip formed is stronger than the echo signal that the stator lateral wall formed.

5. An ultrasonic rotary encoder adapted for miniature shaft rotation measurements as set forth in claim 1 wherein: the stator is close to the end part of the grid bar, the rotor is hollow, and the sensor part comprises a cable which is positioned in the rotor and communicates the ultrasonic sensor with the information transmission part.

6. An ultrasonic rotary encoder adapted for miniature shaft rotation measurements as set forth in claim 1 wherein: the sensor portion further includes a rotational coupling disposed between the stator and the rotor.

7. An ultrasonic rotary encoder adapted for miniature shaft rotation measurements as set forth in 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.

8. The ultrasonic rotary encoder adapted for miniature shaft rotation measurement as set forth in claim 7, wherein: the rotor stretch into be formed with inside sunken mounting groove on the circumference side of stator tip, ultrasonic sensor sets up in the mounting groove.

9. An ultrasonic rotary encoder adapted for miniature shaft rotation measurements as set forth in claim 8 wherein: the mounting groove along rotor length direction extends, ultrasonic sensor with correspond the grating constitutes a set of information acquisition unit, the stator with be formed with multiunit information acquisition unit on the rotor, it is a plurality of ultrasonic sensor arranges in parallel the mounting groove in, every group the grating corresponds and is in side by side on the stator inner wall, a set of in the multiunit the information acquisition unit has one the grating, other groups adjacent two sets of in the information acquisition unit the two sets of grating relative dislocation distribution of information acquisition unit.

10. An ultrasonic rotary encoder adapted for miniature shaft rotation measurements as set forth in claim 9 wherein: the information acquisition unit has three groups, three groups the grating strip sets up side by side the stator inner wall, wherein the grating strip quantity of first row and second row equals to be N, and has 180 degrees/N's angular deviation between the grating strip of first row and second row, and the third row the grating strip quantity is 1, the third row with the second row also be equipped with 180 degrees/N's angular deviation between the grating strip.

Technical Field

The invention belongs to the field of encoders, and particularly relates to an ultrasonic rotary encoder suitable for rotation measurement of a miniature shaft.

Background

The rotary encoder is also called a shaft encoder, is a device that mainly converts a rotational position or a rotational amount into an electronic signal, and can be applied 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 ultrasonic rotary encoder suitable for micro-shaft rotation measurement.

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

an ultrasonic rotary encoder suitable for rotation measurement of a miniature shaft comprises a sensor part, a rotation transmission part and a signal processing part, wherein the rotation transmission part comprises a rotating part for driving a detected shaft to rotate around the axis direction of the detected shaft, an information transmission part communicated with the sensor part and the signal processing part, detection information obtained by the sensor part is transmitted to the signal processing part by the information transmission part, the signal processing part carries out signal analysis to obtain measurement information,

the sensor part comprises a stator with a circular and straight-tube-shaped section, a rotor arranged inside the stator in a free rotating manner around the central line direction of the stator, an ultrasonic sensor fixedly arranged at the end part of the rotor extending into the stator, and a plurality of grid strips uniformly distributed around the circumference of the stator, wherein the rotor is coaxially and fixedly connected with a detected shaft or the rotor and the detected shaft, echo signals formed by the grid strips and the side wall of the stator have intensity difference, and the ultrasonic sensor is positioned in an ultrasonic echo detection area formed by the grid strips.

Preferably, 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 grid bars arranged on the inner wall is that: the ultrasonic echo can be reflected more accurately, and the detection precision is improved.

According to a specific embodiment and a preferred aspect of the present invention, the stator has a notch formed in an inner wall thereof, the grid bars are formed in the notch, and a side surface of the grid bars facing the rotor is flush with an inner wall surface of the stator. Therefore, the grid bars are very convenient to form, ultrasonic echo detection is more accurately realized, and the ultrasonic echo detection device is more attractive.

Preferably, the material of the grating bars is a metal sheet or a metal wire, and the material of the stator is plastic, wherein echo signals formed by the grating bars are stronger than echo signals formed by the side wall of the stator.

According to a further embodiment and preferred aspect of the invention, the stator is arranged closed near the ends of the grid bars. 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 then the ultrasonic wave can be smoothly transmitted between the ultrasonic sensor and the grid bar, and between the ultrasonic sensor and the inner wall of the stator. Preferably, the sensor portion further comprises a rotational connection provided between the stator and said rotor. Such as bearings, are commonly used.

In addition, the detected shaft is a 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.

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

Further, the mounting groove extends along rotor length direction, and ultrasonic sensor and the grating that corresponds constitute a set of information acquisition unit, the stator with be formed with multiunit information acquisition unit on the rotor, a plurality of ultrasonic sensor are side by side in the mounting groove, and every group grating correspondence just is side by side on the stator inner wall, and a set of information acquisition unit in the multiunit has a grating, and two sets of grating of adjacent two sets of information acquisition unit in other group information acquisition units are dislocation distribution relatively.

Specifically, the information acquisition unit has three groups, and three grid bars of group set up side by side at the stator inner wall, and wherein the grid bar quantity of first row and second row equals to be N, and has 180 °/N's angular deviation between the grid bar of first row and second row, the third row grid bar quantity is 1, the third row with the second row also be equipped with 180 °/N's angular deviation between the grid bar.

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 forms the rotation of an ultrasonic echo detection area in a plurality of grid bars and forms echo signals with different strengths to be fed back to the signal processing part for analysis processing, thereby obtaining the detection result, and meanwhile, the invention can carry out accurate detection even if the outer diameter of the detected shaft is less than 1 mm.

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 grid bars 13 is a tungsten wire provided 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 grid bars 13.

As shown in fig. 2, a notch 100 is formed in the inner wall of the stator 10, a grid 13 is formed in the notch 100, and the side surface of the grid 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.

Meanwhile, the stator 10 is made of plastic, and the end part of the stator 10 close to the grid strip 13 is closed, so that after the end part of the stator 10 is closed, a transmission medium, such as water, a saline mixture and other media, can be filled in an ultrasonic echo detection area formed by the stator 10, and then the ultrasonic wave can be smoothly transmitted between the ultrasonic sensor and the grid strip, between the ultrasonic sensor and the inner wall of the stator.

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 grid bar 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.

Referring to 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 the strongest and is Amax, while at the middle position between two adjacent grating strips 13, the reflected echo intensity is the weakest and is Amin, and as for 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 grid 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 grid strip, the strength 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 grid strips, the strength of the reflected echo is weakest and is Amin, and when the transmitting surface of the ultrasonic sensor is at other positions, the strength of the reflected echo is between Amax and Amin;

3) the ultrasonic sensor transmits the collected reflected echo intensity to the signal processing part, and the signal processing part performs data analysis and imaging, wherein the rotating speed and the rotating angle of the detected shaft can be calculated according to imaging information.

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, the ultrasonic sensor continuously transmits and receives ultrasonic signals during the rotation of the ultrasonic sensor, and the value needs to be much larger than n assuming that the number of transmitted signals per rotation is m (because if there are only n signals per rotation of the rotor, that is, each grid bar receives only one echo signal, so that data sampling is far insufficient, and there are enough m transmitted signals to ensure that the amplitude of the received signal is almost continuously changed for each position and adjacent positions).

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.