CN201819692U - Single-code photoelectric encoder for detecting the speed and angle of rotation of rotating objects - Google Patents

Abstract

Disclosed is a single-code-channel photoelectric encoder for detecting rotation speed and rotation angle of a rotating article. A code channel of the single-code-channel photoelectric encoder consists of coding sections and non-coding sections which are arrayed alternately, and each of the coding sections and the non-coding sections consists of light transmitting sectors and impermeable sectors, which have radians theta, by means of arraying. Each non-coding section consists of more than K+2 light transmitting sectors and K+2 impermeable sectors which are arrayed alternately, and the sectors at two ends of each non-coding section are light transmitting sectors, and K is an odd number larger than or equal to three. Each coding section consists of K+2 sectors by arraying, and the sectors at two ends of each coding section are also light transmitting sectors. The array manner of the K sectors of non-end portions of each coding section includes that the K sectors correspond to a set of K-bit binary coding, and the K-bit binary codings of optional two coding sections are different from each other. Interphase radian of two light emitting elements on the code channel d is an odd-number times of half of theta, smaller than the radian of each non-coding section and larger than radian (k+2)*theta of each coding section. The encoder can simultaneously output rotation angle and rotation speed of the rotating article, has only one code channel, and is less in light emitting elements and light-sensitive elements, simple in structure and low in cost.

Description

Single-code photoelectric encoder for detecting the speed and angle of rotation of rotating objects

technical field

The utility model relates to a photoelectric encoder, in particular to a single code track photoelectric encoder for detecting the rotational speed and rotation angle of a rotating object.

Background technique

The photoelectric encoder is used to determine the speed and position of the rotating object. It is a sensor that converts the mechanical geometric displacement on the output shaft into pulse or digital quantity through photoelectric conversion. The photoelectric encoder is composed of a code disc, namely a grating disc, a light-emitting element, a photosensitive element, and a data processing device. Light-emitting elements and light-sensitive elements are distributed on both sides of the code disc. There are light-transmitting and opaque sectors regularly distributed on the code disc. When working, the code disc is coaxial with the motor of the rotating object. When the motor rotates, the code disc and the motor rotate at the same speed. At this time, the light emitted by the light-emitting element passes through the code disc regularly, and the luminous flux received by the photosensitive element is synchronized with the light-transmitting sector. Change, the waveform output by the photosensitive element is transformed into a pulse after being shaped by the data processing device, and the speed, direction and position of the rotating object are determined according to the shape and number of the pulse.

The core component of the photoelectric encoder is the code disk, and the light-transmitting and opaque sectors arranged along concentric circles on the code disk form the code track. There are multiple code tracks on the code disc of the photoelectric encoder, and each code track corresponds to a corresponding light-emitting element and a photosensitive element. The existing photoelectric encoders are mainly of incremental type and absolute type.

The code disk of the incremental encoder has three code tracks. Translucent and opaque sectors with the same radian are alternately distributed on the outermost code track to generate counting pulses; the number of sectors determines the resolution of the encoder, the more sectors, the higher the resolution. There are the same number of fan-shaped areas on the middle circle of code tracks as the outer circle of code tracks, but half of the fan-shaped areas are staggered as the direction-discriminating code tracks. There is only one light-transmitting narrow sector (narrow slit) on the third circle code track, which serves as the reference position of the code disc, and the pulse signal generated will provide an initial zero position (clearing) signal to the counting system. The incremental encoder uses the principle of photoelectric conversion to output three groups of square wave pulses A, B and Z phases through the three code tracks of the encoder disc; the phase difference between the two groups of pulses A and B is 90°, which is used to judge the direction of rotation and speed. The Z phase outputs a pulse for each revolution, which is used for reference point positioning. Incremental encoders require a small number of photosensitive elements and a small number of code tracks, so they have a simple structure, long life, strong anti-interference ability, and high reliability. However, the incremental encoder cannot output the absolute position information and rotation angle of the shaft rotation, and a reference point positioning pulse is required; if there is a missing or wrong pulse signal during the rotation of the object, the error will affect the rotation angle detection result. It exists all the time, and will further generate cumulative errors, which cannot be corrected until the reference point positioning signal is obtained. Therefore, the reference point must be determined before each incremental photoelectric encoder is used.

The code disk of the absolute encoder has N concentric code tracks, each code track is composed of light-transmitting and opaque sectors, and each code track corresponds to a photosensitive element. When working, when the code disc rotates at different positions, each photosensitive element converts the corresponding high and low level signals according to whether the fan-shaped area of the code track at the position is transparent or not, forming a digital binary code. Corresponds to the number of code tracks on the code disc; the binary codes formed by each code track at different angles are different, so the absolute encoder uses the method of marking the spatial position to convert the position of the rotating object into a digital binary code, so that it is on the axis of rotation A fixed digital code can be read at any position. Obviously, the more code tracks, the higher the resolution. For an encoder with N-bit binary resolution, its code disc has N code tracks. Its characteristics are: the absolute value of the angular coordinate can be read directly; there is no cumulative error; the position information will not be lost after the power is cut off. However, the absolute encoder has a large number of code channels, the structure of the encoder disk is complicated, the precision is high, and the production is difficult; and with the increase of the resolution, the cost and the production difficulty increase correspondingly, which limits its application.

Utility model content

The purpose of this utility model is to provide a single-code photoelectric encoder for detecting the rotating speed and rotation angle of a rotating object. The encoder can output the rotating angle of the rotating object and the rotating speed of the rotating object; The number of light-emitting elements and light-sensitive elements is small, the structure is simple, and the cost is low.

The technical solution adopted by the utility model to achieve its purpose is: a single code track photoelectric encoder for detecting the rotating speed and rotation angle of a rotating object, including a circular code disc, which is provided with a code track, and the code track is formed by a light-transmitting Sectors and opaque sectors, the two sides of the coding disc are also equipped with light-emitting elements and photosensitive elements opposite to each other; the photosensitive elements are connected to the data processing device, and its structural characteristics are: the code track is composed of a coding segment and a non-coding segment. Segments are alternately arranged, and both the coding segment and the non-coding segment are composed of light-transmitting and opaque sector arrangements with a radian of θ, where:

The non-coding segment is composed of more than K+2 light-transmitting and opaque sectors alternately arranged, and the sectors at both ends are light-transmitting sectors, and K is an odd number greater than or equal to 3;

The coding segment is composed of K+2 light-transmitting and opaque sectors, and the sectors at both ends are also light-transmitting sectors; the arrangement of the K sectors at the non-end of the coding segment is: transparent The logical value corresponding to the optical sector is 0, the logical value corresponding to the opaque sector is 1, and the middle sector of a coding segment corresponds to a K-bit binary code; and any two coding segments have different binary codes;

There are two light-emitting elements and photosensitive elements on the code track respectively, and the radian d between the two light-emitting elements is an odd multiple of θ/2, and is less than the radian of the non-coding segment, and greater than the radian (k+2)θ of the encoding segment

Working process and principle of the present utility model are:

Since the non-coding section is composed of alternately arranged light-transmitting and opaque sectors, and the radian d between the two light-emitting elements is an odd multiple of θ/2, it is smaller than the radian of the non-coding section and greater than the radian of the coding section (k+ 2) θ, so there are only two situations where one photosensitive element is in the coding segment and the other is in the non-coding segment or both photosensitive elements are in the non-coding segment; that is, at any moment, there is always one photosensitive element in the non-coding segment .

With the rotation of the object, the output signal of any photosensitive element in the non-encoded section is processed to obtain a continuous pulse signal with high and low levels alternately. Since the radian θ of each sector is determined, according to The number of pulses detected within a specific time can be used to calculate the speed of the object and the relative rotation angle at the current moment.

When the two photosensitive elements are located in the non-coding section, since the radian d between the two photosensitive elements is an odd multiple of θ/2, the two-phase pulse signals obtained by the two photosensitive elements differ by 1/4 period, according to the direction of the phase difference The direction of rotation of the object can be determined.

Since both ends of each coding segment and both ends of the non-coding segment adjacent to the coding segment are light-transmitting sectors, when the output pulse signal of one of the two photosensitive elements jumps twice, that is, 0-1- 0 or 1-0-1, and another output signal with a difference of 1/4 cycle is 00, indicating that the latter has entered the coding segment; then at each jump moment of the output pulse signal of the photosensitive element in the non-coding segment, read Take the output signal of the photosensitive element that has entered the coding section, and the read K signals are used as K-bit binary codes; after reading the K-bit code, when the photosensitive element outputs 00 signals continuously again, it indicates that the photosensitive element has left the coding section into the non-coding segment. Since the K-bit binary codes of any two coded segments are different, each coded segment has a unique coded value, which is in one-to-one correspondence with its position. The data processing device can accurately determine the absolute rotation angle of the object according to the code value of the current code section read by the photosensitive element.

Compared with the prior art, the beneficial effects of the utility model are:

The non-coding segment and the coding segment are sequentially distributed on a code track, and the coded information is read by two photosensitive elements. Compared with the existing incremental encoder, since the coding segment in the utility model is equivalent to a plurality of positioning reference points set in the non-coding segment, it can significantly reduce the omission or miscalculation of the positioning pulse signal. The accumulative error generated thereby improves the detection accuracy; meanwhile, with the use of the coding section, the device of the utility model can also detect the absolute position of the rotating object at the position of the coding section. Therefore, the utility model device has the functions of existing incremental and absolute encoders. Compared with the absolute encoder, the utility model only needs one code channel, two groups of light-emitting and photosensitive elements. It is only 1/K of the absolute encoder, its quantity is greatly reduced, the structure is obviously simplified, the cost is lower, and the reliability is high.

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail.

Description of drawings

Fig. 1 is a schematic structural diagram of an encoder disc in Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of the encoder disc in FIG. 1 after it has been rotated clockwise by 80°.

FIG. 3 is a side view of FIG. 1 .

Detailed ways

Embodiment one

Fig. 1, 2, 3 show, a kind of embodiment of the present utility model is:

A single code track photoelectric encoder for detecting the rotational speed and rotation angle of a rotating object, including a circular code disc 1, on which a code track is arranged, and the code track is composed of a light-transmitting sector 3a and an opaque sector 3b , On both sides of the code disk 1 there are also light-emitting elements 4 and photosensitive elements 5 opposite to each other; the photosensitive elements 5 are connected to the data processing device. The code track is composed of coded segment 2a and non-coded segment 2b arranged alternately, and the coded segment 2a and non-coded segment 2b are both composed of transparent and opaque sectors with a radian of θ, where:

The non-coding segment 2b is composed of more than K+2 light-transmitting and opaque sectors alternately arranged, and the sectors at both ends are light-transmitting sectors 3a, and K is an odd number greater than or equal to 3;

The coding segment 2a is composed of K+2 light-transmitting and opaque sectors, and the sectors at both ends are also light-transmitting sectors 3a; the arrangement of the K sectors at the non-end of the coding segment is as follows: : The logic value corresponding to the light-transmitting sector 3a is 0, the logic value corresponding to the opaque sector 3b is 1, and the middle sector of a coding segment corresponds to a group of K-bit binary codes; and the K of any two coding segments Bit binary codes are all different;

There are two light-emitting elements 4 and photosensitive elements 5 on the code track respectively, and the radian d between the two light-emitting elements 4 is an odd multiple of θ/2, and is less than the radian of the non-coding segment, and greater than the radian of the encoding segment (k+ 2) θ.

As shown in FIG. 1 , the specific value of K in this example is 3, and the non-coding segment 2b is composed of 13 (greater than 5) transparent and opaque sectors arranged alternately. The coding segment 2a is composed of K+2=5 light-transmitting and opaque sector arrangements. There are four non-encoding segments 2b and four encoding segments 2a, the total number of sectors on the encoding disk is (13+5)*4=72, and the arc of each sector is 5°.

The arrangement of the K=3 sectors at the non-end portion of the coding segment is: the logic value corresponding to the light-transmitting sector 3a is 0, the logic value corresponding to the opaque sector 3b is 1, the middle sector of a coding segment The 3 logical values correspond to a set of 3-bit binary codes; and the 3-bit binary codes of any two coded segments are different; in Figure 1, the codes of the four coded segments arranged counterclockwise from the right are respectively It is 000, 001, 010, 011.

In this example, the distance between the two photosensitive elements is 32.5°, which is 25° greater than the radian of a coded segment and 65° less than the arc of the non-coded segment, which ensures that the two photosensitive elements 5 can only be located in the non-coded segment 2b at the same time , or one is in the non-coding section 2b and the other is in the coding section 2a, there will be no situation where the two photosensitive elements 5 are all located in the coding section 2a.

The photosensitive element 5 of the non-coding section 2b outputs continuously changing pulse signals of high and low levels alternately. Since the radian θ of each sector is determined, the object can be calculated according to the number of pulses detected within a specific time. The rotational speed and the relative rotation angle at the current moment.

Assuming that the object rotates clockwise, starting from the current position in Figure 1, the lower photosensitive element 5 is in the non-coding segment, and will output 101 in sequence, that is, two jumps of 1-0-1 occur, while the upper photosensitive element 5 outputs continuously 00 means that the upper photosensitive element 5 enters the coding segment. Subsequently, the output of the upper photosensitive element 5 is read at the 3 transition moments of the output signal of the lower photosensitive element 5, and the read 3 signals 000 are regarded as 3-bit binary code 000. Assuming that the absolute rotation angle of the object is 0°, according to the above analysis, it can be drawn from FIG. 1 that the encoded signals read by the upper photosensitive element 5 through each encoding segment and their corresponding absolute rotation angles are shown in Table 1.

Table 1

Upper photosensitive element 5 Absolute corner 000 0° 001 90° 010 180° 011 270°

It can also be concluded that the object rotates in a clockwise direction, and the encoded signal and its corresponding absolute rotation angle are shown in Table 2 when the lower photosensitive element 5 passes through the encoded section.

Table 2

Lower photosensitive element 5 Absolute corner 000 32.5° 001 122.5° 010 212.5° 011 302.5°

FIG. 2 shows that when the code disk 1 is rotated clockwise by 80° from the position shown in FIG. 1 , the two photosensitive elements 5 are both on the non-coding segment 2b. Since the two-phase pulse signals obtained by the two photosensitive elements 5 differ by 1/4 period, the rotation direction of the object can be determined according to the direction of the phase difference.

The sector in this example has a width of 5°. In actual application, the narrower the width of the sector, the more the number of sectors, and the more encoding bits in the encoding segment, the higher the detection accuracy will be.

When the utility model is applied in practice, increasing the number of coding digits K and the number of coding segments can reduce the gap of the absolute angle, and further improve the precision and accuracy of detecting the absolute angle.

The light-transmitting sector and the opaque sector are replaced by non-metal material sectors and metal material sectors, the corresponding light-emitting elements are replaced by high-frequency signal transmitters, and the photosensitive elements are replaced by electromagnetic induction sensors, which can also fully realize the utility model. The purpose of the new model is the equivalent technical solution of the utility model, which belongs to the protection scope of the utility model.

Claims (1)

1. solid size road photoelectric encoder that detects the rotating object rotating speed and the anglec of rotation, comprise circular code-wheel (1), code-wheel (1) is provided with code channel, code channel is made up of printing opacity sector (3a) and light tight sector (3b), and code-wheel (1) both sides also are provided with relative light-emitting component in position (4) and light activated element (5); Light activated element (5) links to each other with data processing equipment, it is characterized in that: described code channel is alternately rearranged by coding section (2a) and non-coding section (2b), coding section (2a) and non-coding section (2b) they are printing opacity and the lighttight sector alignment formation of θ by radian, wherein:

Described non-coding section (2b) is by alternately rearranging greater than K+2 printing opacity and lighttight sector, and the sector at two ends is printing opacity sector (3a), and K is the odd number more than or equal to 3;

Described coding section (2a) is made up of K+2 printing opacity and lighttight sector alignment, and the sector at two ends also is printing opacity sector (3a); The arrangement mode of the K of the non-end of a coding section sector is: the logical value that printing opacity sector (3a) is corresponding is 0, and the logical value that light tight sector (3b) is corresponding is that the intermediate sectors of 1, one coding section is corresponding to one group of K position binary coding; And the K position binary coding of any two coding sections is all inequality;

Light-emitting component on the described code channel (4) and light activated element (5) are respectively two, and the radian d that two light-emitting components (4) are alternate is the odd-multiple of θ/2, and less than the radian of non-coding section, greater than radian (k+2) θ of coding section.

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