An absolute angle measuring device and method

Abstract

The present invention discloses an absolute angle measuring device and method. The device includes a laser, a circular diffraction optical waveguide grating code disk, and a light intensity sensor. The diffraction optical waveguide grating code disk rotates around a rotating shaft located inside it. A plurality of incident coupling gratings are provided on the circular diffraction optical waveguide grating code disk. The laser is arranged on one side of the diffraction optical waveguide grating code disk and directly above an incident coupling grating, so that the laser beam emitted by the laser irradiates the incident coupling grating. The light intensity sensor is arranged above the diffraction optical waveguide grating code disk to obtain the light exiting from the upper surface of the diffraction optical waveguide grating code disk and output an electrical signal. Among them, the magnitude of the electrical signal corresponds to the position of the diffraction optical waveguide grating code disk. The diffraction optical waveguide grating code disk structure and pattern of the present invention are simple. By using a single linear optoelectronic device, the absolute positioning function can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of angle measurement, and particularly to an absolute angle measurement device and method. Background Art

[0002] An absolute angle measurement device can directly obtain absolute position information at any time, and is an irreplaceable position sensor in robots and automated equipment. Its core is to generate a unique position code without relying on historical data to calculate the current position.

[0003] For absolute angle sensors, currently commonly used are photoelectric Gray codes, photoelectric pseudo-random sequences, and magnetic grating technologies. Among them, for the Gray code encoding method, adjacent code values only change by 1 bit, having high error resistance, but multiple code tracks are required, and as the positioning resolution increases, the required number of code tracks also increases accordingly.

[0004] Pseudo-random codes only require one code track, but adjacent position codes change by multiple bits, making it easy to generate errors. And multiple micro-sensors are required to measure each code bit.

[0005] For the magnetic grating solution, the position resolution and accuracy are both lower than those of the photoelectric measurement method. And magnetic devices cannot be applied in high-temperature environments. Summary of the Invention

[0006] In view of this, the present invention provides an absolute angle measurement device and method to solve the above technical problems.

[0007] The present invention discloses an absolute angle measurement device, which includes a laser, a circular diffraction optical waveguide grating code disk, and a light intensity sensor;

[0008] The diffraction optical waveguide grating code disk rotates around a rotating shaft located inside it;

[0009] A plurality of incident coupling gratings are arranged on the circular diffraction optical waveguide grating code disk;

[0010] The laser is arranged on one side of the diffraction optical waveguide grating code disk and directly above an incident coupling grating, so that the laser beam emitted by it irradiates on the incident coupling grating;

[0011] The light intensity sensor is arranged above the diffraction optical waveguide grating code disk, acquires the light exiting from the upper surface of the diffraction optical waveguide grating code disk, and outputs an electrical signal; wherein, the magnitude of the electrical signal corresponds to the position of the diffraction optical waveguide grating code disk.

[0012] Further, the rotating shaft is perpendicular to the diffraction optical waveguide grating code disk and passes through the center of the diffraction optical waveguide grating code disk.

[0013] Further, the diffractive optical waveguide grating code disk further includes a glass substrate and a reflective aluminum layer;

[0014] The reflective aluminum layer and the incident coupling grating are concentrically arranged on the glass substrate;

[0015] The incident coupling grating is symmetrically and fixedly arranged on the diffractive optical waveguide grating code disk.

[0016] Further, the glass substrate is a glass substrate body without aluminum film covering.

[0017] Further, the incident coupling grating and the reflective aluminum layer are both prepared by vacuum coating, photolithography and etching processes without using nanoimprinting.

[0018] Further, the incident coupling grating includes three layers of gratings stacked in sequence, and there is no contact between adjacent two layers of gratings; wherein, the structures of the top two layers of gratings are the same, both are a plurality of rectangular gratings connected in sequence and arranged in a stepped shape; the shape of the bottom layer grating is rectangular and it is parallel to the rectangular gratings in the top two layers of gratings respectively.

[0019] The present invention also discloses an absolute angle measurement method, which includes the following steps:

[0020] The laser beam emitted by the laser irradiates on the incident coupling grating, and the generated diffracted lights of each order enter the glass substrate, and the diffracted lights of each order have different incident angles;

[0021] All the lights entering the glass matrix propagate inside the glass, but only the diffracted light that satisfies the total reflection incident angle can propagate to the reflective aluminum layer, and for the lights with the remaining incident angles, at each reflection point, part of the light refracts into the air, and when reaching the reflective aluminum layer, it has been greatly attenuated;

[0022] The light reaching the reflective aluminum layer is reflected by the reflective aluminum layer and exits from the upper surface of the diffractive optical waveguide grating code disk, and is obtained by the light intensity sensor and outputs an electrical signal.

[0023] Further, by adjusting the grating parameters and patterns of the incident coupling grating, the light intensity exiting from the reflective aluminum layer can be controlled, and further, a characteristic light intensity can be designed for each position to form an absolute position sensor, that is, an absolute angle measurement device.

[0024] Further, different grating parameters result in different incident angles of the interference light waves, and different degrees of attenuation are generated when conducting in the glass substrate, and each position corresponds to a unique light intensity, realizing absolute position positioning.

[0025] Due to adopting the above technical solution, the present invention has the following advantages:

[0026] 1. The diffraction optical waveguide grating code disk structure has a simple pattern; by using a single linear optoelectronic device, the absolute positioning function is achieved;

[0027] 2. The diffraction grating coupling structure has high optical efficiency and is easy to precisely control the illumination intensity of the transmitted light;

[0028] 3. By making full and ingenious use of the refractive characteristics of glass, the non-total reflection light is naturally and effectively attenuated during the conduction process, improving the signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of a circular diffraction optical waveguide grating code disk according to an embodiment of the present invention;

[0031] Figure 2 It is a schematic structural diagram of an absolute angle measuring device according to an embodiment of the present invention;

[0032] Figure 3 It is a schematic pattern diagram of an incident coupling grating according to an embodiment of the present invention;

[0033] Figure 4 It is a schematic flowchart of an absolute angle measuring method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The present invention will be further described in conjunction with the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art shall fall within the scope of protection of the embodiments of the present invention.

[0035] Refer to Figure 1 and Figure 2 , the present invention provides an embodiment of an absolute angle measuring device, which includes a laser 4, a circular diffraction optical waveguide grating code disk, and a light intensity sensor 5;

[0036] The diffraction optical waveguide grating code disk rotates around a rotating shaft 6 located inside it; wherein, Figure 2 What is shown is the structure of the diffraction optical waveguide grating code disk rotating around the rotating shaft 6 located inside it;

[0037] A plurality of incident coupling gratings 3 are provided on the circular diffraction optical waveguide grating code disk;

[0038] The laser 4 is arranged on one side of the diffractive optical waveguide grating code disk and directly above an incident coupling grating 3, so that the laser beam emitted by it irradiates the incident coupling grating 3;

[0039] The light intensity sensor 5 is arranged above the diffractive optical waveguide grating code disk, acquires the light emerging from the upper surface of the diffractive optical waveguide grating code disk and outputs an electrical signal; wherein, the magnitude of the electrical signal corresponds to the position of the diffractive optical waveguide grating code disk.

[0040] In this embodiment, the rotating shaft 6 is perpendicular to the diffractive optical waveguide grating code disk and passes through the center of the diffractive optical waveguide grating code disk.

[0041] In this embodiment, the diffractive optical waveguide grating code disk further includes a glass substrate 2 and a reflective aluminum layer 1;

[0042] The reflective aluminum layer 1 and the incident coupling grating 3 are concentrically arranged on the glass substrate 2;

[0043] The incident coupling grating 3 is symmetrically and fixedly arranged on the diffractive optical waveguide grating code disk.

[0044] In this embodiment, the glass substrate 2 is the glass substrate 2 body without aluminum film covering.

[0045] In this embodiment, both the incident coupling grating 3 and the reflective aluminum layer 1 are prepared by vacuum coating, photolithography and etching processes without using nanoimprinting.

[0046] In this embodiment, referring to Figure 3 , the incident coupling grating 3 includes three layers of gratings stacked in sequence, and the adjacent two layers of gratings do not contact each other; wherein, the structures of the top two layers of gratings are the same, both are a plurality of rectangular gratings connected in sequence and arranged in a stepped shape; the shape of the bottom layer grating is rectangular and it is parallel to the rectangular gratings in the top two layers of gratings respectively.

[0047] Referring to Figure 4 , the present invention also discloses an embodiment of an absolute angle measurement method, which includes the following steps:

[0048] S1. The laser beam emitted by the laser 4 irradiates the incident coupling grating 3, and the generated diffracted lights of each order enter the glass substrate 2, and the diffracted lights of each order have different incident angles;

[0049] S2. All the light entering the glass matrix propagates inside the glass, but only the diffracted light that satisfies the total reflection incident angle can propagate to the reflective aluminum layer 1, and for the light with the remaining incident angles, at each reflection point, part of the light refracts into the air, and when it reaches the reflective aluminum layer 1, it has been greatly attenuated;

[0050] S3. The light reaching the reflective aluminum layer 1 is reflected by the reflective aluminum layer 1 and exits from the upper surface of the diffraction optical waveguide grating disk, and is obtained by the light intensity sensor 5 to output an electrical signal.

[0051] In this embodiment, by adjusting the grating parameters and patterns of the incident coupling grating 3, the light intensity exiting from the reflective aluminum layer 1 can be controlled, and thus a characteristic light intensity can be designed for each position to form an absolute position sensor, that is, an absolute angle measuring device.

[0052] In this embodiment, different grating parameters result in different incident angles of the interfering light waves, and different degrees of attenuation occur during the propagation in the glass substrate 2. Each position corresponds to a unique light intensity, realizing absolute position positioning.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. An absolute angle measuring device, characterized in that, it includes a laser, an annular diffractive optical waveguide grating disk, and a light intensity sensor; the diffractive optical waveguide grating disk rotates around a rotating shaft located inside it; a plurality of incident coupling gratings are arranged on the annular diffractive optical waveguide grating disk; the laser is arranged on one side of the diffractive optical waveguide grating disk and directly above an incident coupling grating, so that the laser beam emitted by it irradiates onto the incident coupling grating; the light intensity sensor is arranged above the diffractive optical waveguide grating disk, obtains the light exiting from the upper surface of the diffractive optical waveguide grating disk, and outputs an electrical signal; wherein, the magnitude of the electrical signal corresponds to the position of the diffractive optical waveguide grating disk; the incident coupling grating includes three layers of gratings stacked in sequence, and there is no contact between adjacent two layers of gratings; wherein, the structures of the top two layers of gratings are the same, both are a plurality of rectangular gratings connected in sequence and arranged in a stepped shape; the shape of the bottom layer grating is rectangular, and it is parallel to the rectangular gratings in the top two layers of gratings respectively; the diffractive optical waveguide grating disk further includes a glass substrate and a reflective aluminum layer; the reflective aluminum layer and the incident coupling grating are concentrically arranged on the glass substrate; the incident coupling grating is symmetrically and fixedly arranged on the diffractive optical waveguide grating disk; by adjusting the grating parameters and patterns of the incident coupling grating, the light intensity exiting from the reflective aluminum layer can be controlled, and thus a characteristic light intensity can be designed for each position, forming an absolute position sensor, that is, an absolute angle measuring device; different grating parameters result in different incident angles of the interfering light waves, and different degrees of attenuation occur when propagating in the glass substrate. Each position corresponds to a unique light intensity, realizing absolute position positioning.

2. The absolute angle measuring device according to claim 1, characterized in that, the rotating shaft is perpendicular to the diffractive optical waveguide grating disk and passes through the center of the diffractive optical waveguide grating disk.

3. The absolute angle measuring device according to claim 1, characterized in that, the glass substrate is a glass substrate body without aluminum film coverage.

4. The absolute angle measuring device according to claim 1, characterized in that, the incident coupling grating and the reflective aluminum layer are both prepared by vacuum coating, photolithography, and etching processes without using nanoimprinting.

5. An absolute angle measuring method based on the absolute angle measuring device according to any one of claims 1 to 4, characterized in that, the method includes the following steps: the laser beam emitted by the laser irradiates onto the incident coupling grating, and the generated diffracted lights of each order enter the interior of the glass substrate, and the diffracted lights of each order have different incident angles; all the light entering the glass matrix propagates inside the glass, but only the diffracted light that satisfies the total reflection incident angle can propagate to the reflective aluminum layer, and for the light with other incident angles, at each reflection point, part of the light refracts into the air, and when it reaches the reflective aluminum layer, it has been greatly attenuated; the light reaching the reflective aluminum layer is reflected by the reflective aluminum layer and exits from the upper surface of the diffractive optical waveguide grating disk, is obtained by the light intensity sensor, and outputs an electrical signal.

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