A high-precision displacement measurement sensor based on hybrid gratings

Abstract

This utility model relates to the field of grating displacement sensor technology, specifically a high-precision displacement measurement sensor based on a hybrid grating. It includes a grating ruler mounted at the rear end of a machine tool slide, a sensor, a side cover, a ruler platform vibration damping component, a slide rail vibration damping component, and an adjustable rolling vibration damping component. This utility model addresses the scenario where older lathes have limited space at the tool end, making it impossible to install a grating ruler; it can only be installed on the moving end. However, high-frequency vibrations generated during the machining of shaft-type workpieces lead to decreased measurement accuracy. Through a dual-coordinated structure of "fixed-end vibration damping plus moving-end vibration damping," high-frequency vibrations are pre-intercepted and attenuated secondaryly, preventing deformation of the grating ruler body and deviation of the reading head. Compared to the traditional single metal rubber vibration isolation pad method, this significantly improves the high-frequency vibration attenuation effect, ensuring micron-level measurement accuracy, meeting the machining requirements of high-precision, high-consistency workpieces, and reducing the workpiece scrap rate due to measurement errors.

Description

Technical Field

[0001] This utility model relates to the field of grating displacement sensor technology, specifically a high-precision displacement measurement sensor based on a hybrid grating. Background Technology

[0002] Hybrid grating high-precision displacement measurement sensors are devices that utilize hybrid grating technology to achieve high-precision displacement measurement, and have important applications in semiconductor manufacturing, precision machining, and other fields. Their core principle is to use the optical diffraction / interference effect of the grating to convert mechanical displacement into an electrical signal. They are commonly used in machine tools (lathes, milling machines), precision machining equipment, measuring instruments, and other scenarios to achieve digital display or automated control of displacement, and feature high detection accuracy and fast response speed.

[0003] In machine tools, precision machining, and automated production lines, workpieces are clamped on slide fixtures for fine or rough machining. During turning, the workpiece is clamped on the lathe's slide fixture. The impact contact between the tool and the workpiece causes the machine tool slide to vibrate. Since the hybrid grating high-precision displacement measurement sensor is generally installed on the moving end of the machine tool, that is, the rear surface of the slide, the vibration is transmitted to the slide through the tool holder, which causes the grating reading head to be forced to resonate. In order to avoid the grating sensor being forced to resonate, in the existing technology, the grating ruler is mostly installed at the end of the tool, on the same side and the same guide rail surface as the tool. When the grating ruler and the tool are fixed on the same side and the same guide rail surface, the distance between the grating ruler and the tool is compressed to the minimum, or even almost coincident. This makes the measurement reference and the machining reference as coincident as possible, shortening the error transmission path caused by vibration from the physical structure, and ultimately achieving the lowest vibration coupling and stable displacement measurement accuracy. However, some factories are still using old lathes that were not originally equipped with linear encoders. Some customers require customized high-precision, high-consistency workpieces, so to meet these needs, hybrid linear encoder high-precision displacement measurement sensors are added to the old lathes to achieve closed-loop control, enabling high-precision machining. Due to the limited space at the tool tip of the old lathes, it's impossible to install linear encoders directly; therefore, they are mounted on the rear face of the slide plate. This allows for real-time feedback of the slide plate's actual position, and stroke compensation is performed through the closed-loop control system. However, the linear encoder mounted on the rear face of the slide plate will resonate with vibrations generated during machining. To ensure the linear encoder... When the ruler is installed on the rear surface of the slide plate, the stability of the displacement measurement process of the grating sensor is achieved by adding multiple layers of metal rubber vibration isolation pads to the grating ruler and the rear surface of the slide plate. The elastic deformation of the vibration isolation pads absorbs the vibration of the slide plate. However, when performing high-precision machining on shaft-type workpieces, the tool does not always cut against the workpiece, but rather "cuts in and then leaves", repeatedly moving around, which generates high-frequency vibration. Even with the addition of multiple layers of metal rubber vibration isolation pads, it is still impossible to attenuate the vibration force to a controllable range. Consequently, when the sensor reading head moves inside the grating ruler to perform stroke compensation, it still leads to a decrease in measurement accuracy, resulting in random measurement errors, which in turn cause the tool movement trajectory to deviate from the ideal path.

[0004] To address this, a high-precision displacement measurement sensor based on a hybrid grating is proposed. Utility Model Content

[0005] The purpose of this invention is to provide a high-precision displacement measurement sensor based on a hybrid grating. By adding a vibration damping structure to both the fixed and moving ends, it solves the problem of high-frequency vibrations during machining causing resonance of the grating sensor and displacement of the reading head when the grating ruler cannot be installed on the back surface of the slide due to limited space at the tool end of old lathes. This leads to decreased measurement accuracy, random errors, and tool trajectory deviation. The sensor features dual attenuation of high-frequency vibrations, ensures the stability of the grating ruler body and the stable contact between the sensor reading head and the sensor, is suitable for installation on old machine tools, achieves micron-level measurement accuracy, and allows the sensor to slide smoothly without jamming and with minimal wear during long-term operation.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A high-precision displacement measurement sensor based on a hybrid grating includes a grating ruler disposed at the rear end of a machine tool slide, a sensor, a side cover, a scale platform vibration damping assembly, a slide rail vibration damping assembly, and an adjustable rolling vibration damping assembly. The sensor is disposed at the top of the grating ruler, and a reading head that can slide inside the grating ruler is fixed at the bottom of the sensor. The side cover is symmetrically fixed on both sides of the grating ruler. The scale platform vibration damping assembly is fixed to the rear end of the machine tool slide and is fixedly connected to the grating ruler. The slide rail vibration damping assembly is disposed inside the grating ruler and connected to the reading head of the sensor. The adjustable rolling vibration damping assembly is disposed on both sides of the slide rail vibration damping assembly. When the sensor moves laterally, the reading head synchronously drives the slide rail vibration damping assembly and the adjustable rolling vibration damping assembly to move laterally in the same direction.

[0007] Preferably, the vibration damping assembly of the scale includes a fixed plate, a limiting groove, multiple soft pads, screw holes, and screws. The fixed plate is fixed to the rear end of the machine tool slide, and its top end is in contact with the bottom end of the grating ruler. The limiting groove is symmetrically opened on both sides of the top end of the fixed plate and is engaged with the bottom end of the side cover. The multiple soft pads are fixed to the rear end of the machine tool slide and are in contact with the front end of the grating ruler. Screw holes are opened at the rear end of the machine tool slide and the rear end of the side cover, and the two screw holes are coaxial. The screw is set at the rear end of the side cover and is screwed into the screw hole. An anti-loosening washer is provided between the screw and the side cover.

[0008] Preferably, a slightly deformable Z-shaped rubber pad is fixedly disposed inside the multi-layer soft pad, and a double-layer rubber pad is fixedly disposed inside the Z-shaped rubber pad.

[0009] Preferably, the slide rail vibration damping assembly includes a slide groove, a slider, a built-in elongated pad, and an arc-shaped pad. The slide groove is symmetrically opened inside the grating ruler. The slider is fixed on both sides of the reading head and is slidably connected to the slide groove. The built-in elongated pad is fixed to the inner wall of the slide groove. The arc-shaped pad is fixed to the end of the slider and slides in contact with the built-in elongated pad.

[0010] Preferably, the adjustable rolling damping assembly includes a side groove, a fixed bracket, a buffer plate, multiple elastic plates, layered buffer pads, and an adjusting nut. The side groove is symmetrically opened on both sides of the slide groove. The fixed bracket is symmetrically fixed on both sides of the slider. The buffer plate is sleeved on the end of the fixed bracket and is slidably connected to the fixed bracket. The multiple elastic plates are sleeved on the surface of the fixed bracket and are located between the buffer plate and the fixed bracket. The layered buffer pads are sleeved on the surface of the fixed bracket and are located at the contact point between the multiple elastic plates. The adjusting nut is screwed and fixed to the end of the fixed bracket and is pressed and fitted against the buffer plate. An anti-loosening washer is provided between the adjusting nut and the buffer plate.

[0011] Preferably, the end of the buffer sheet is fixed with a support, and the end of the support is provided with circular grooves at equal intervals. Universal balls are provided inside the circular grooves, and the universal balls roll in contact with the inner wall of the side groove.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention addresses the scenario where limited space at the tool end of older lathes prevents the installation of optical scales, limiting their installation to the moving end. However, high-frequency vibrations during the machining of shaft-type workpieces can lead to decreased measurement accuracy. A dual-synergistic structure combining "fixed-end vibration damping and moving-end vibration damping" pre-intercepts and secondary attenuates high-frequency vibrations, preventing deformation of the optical scale body and deviation of the reading head. Compared to traditional single-metal rubber vibration isolation pads, this significantly improves the attenuation effect of high-frequency vibrations, ensuring micron-level measurement accuracy. This meets the machining requirements of high-precision, high-consistency workpieces and reduces workpiece scrap rates due to measurement errors. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 For the present utility model Figure 2 Enlarged schematic diagram of the structure at point A in the middle; Figure 3 This is a schematic diagram of the grating ruler track structure of this utility model; Figure 4 This is a side view of the grating ruler track structure of this utility model; Figure 5 For the present utility model Figure 4 Enlarged structural diagram at point B; Figure 6 For the present utility model Figure 5 Enlarged structural diagram at point C; Figure 7 This is a cross-sectional view of the multi-layer soft pad structure of this utility model.

[0014] In the diagram: 1. Machine tool slide plate; 2. Grating ruler; 3. Sensor; 4. Side cover; 5. Ruler platform vibration damping assembly; 51. Fixing plate; 52. Limiting groove; 53. Multi-layer soft pad; 531. Z-shaped rubber pad; 532. Double-layer rubber pad; 54. Screw hole; 55. Screw; 6. Slide rail vibration damping assembly; 61. Slide groove; 62. Slider; 63. Built-in long strip pad; 64. Arc-shaped pad; 7. Adjustable rolling vibration damping assembly; 71. Side groove; 72. Fixing bracket; 73. Buffer plate; 74. Elastic plate; 75. Layered buffer pad; 76. Adjusting nut; 77. Support; 78. Circular groove; 79. Universal ball bearing. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0016] Please see Figures 1 to 7 This utility model provides a high-precision displacement measurement sensor based on a hybrid grating, the technical solution of which is as follows: Reference Figure 1 , Figure 2 , Figure 5 and Figure 6 A high-precision displacement measurement sensor based on a hybrid grating includes a grating ruler 2 located at the rear end of a machine tool slide plate 1, a machine mounting base (the moving end of the machine tool where workpieces are clamped for processing and providing a fixed carrier for the grating ruler 2), a sensor 3, side covers 4, a scale platform vibration damping assembly 5, a slide rail vibration damping assembly 6, and an adjustable rolling vibration damping assembly 7. The sensor 3 is located at the top of the grating ruler 2, and a reading head that can slide inside the grating ruler 2 is fixed to the bottom of the sensor 3. The side covers 4 are symmetrically fixed on both sides of the grating ruler 2. The scale platform vibration damping assembly 5 is fixed to the rear end of the machine tool slide plate 1 and is fixedly connected to the grating ruler 2. The fixed end is a primary vibration damping core, connecting the machine tool slide plate 1 and the grating ruler 2, used to intercept and attenuate the vibration transmitted by the machine tool slide plate 1, preventing the grating ruler 2 from undergoing minor deformation or displacement due to vibration, providing a stable mounting reference for the grating ruler 2, and reducing the impact of vibration on the measurement reference. The slide rail vibration damping assembly... 6 is located inside the grating ruler 2 and connected to the reading head of the sensor 3. It is a guide and secondary vibration damping component at the moving end, connecting the inside of the grating ruler 2 and the reading head of the sensor 3. It provides precise guidance for the lateral movement of the reading head and offsets some residual vibration through the sliding structure, ensuring stable contact between the reading head and the slide rail of the grating ruler 2. This avoids measurement errors caused by gap fluctuations during sliding. The adjustable rolling vibration damping component 7 is located on both sides of the slide rail vibration damping component 6. It is an adjustable vibration damping and friction reduction component at the moving end, located on both sides of the slide rail vibration damping component 6. It works with the slide rail vibration damping component 6 to further attenuate residual vibration. At the same time, it reduces sliding friction through rolling contact, reducing wear after long-term operation. It can also be adapted to different vibration conditions through adjustment structure, balancing vibration reduction effect and sliding smoothness. When the sensor 3 moves laterally, it drives the slide rail vibration damping component 6 and the adjustable rolling vibration damping component 7 to move laterally in the same direction through the reading head.

[0017] Reference Figure 1 and Figure 2As one embodiment of this utility model, specifically, the scale table vibration damping component 5 includes a fixing plate 51, a limiting groove 52, a multi-layer soft pad 53, a screw hole 54, and a screw 55. The fixing plate 51 is fixed to the rear end of the machine tool slide plate 1, and its top end is attached to the bottom end of the grating ruler 2. The bottom support and positioning components of the grating ruler 2 provide a horizontal support reference for the grating ruler 2, ensuring the horizontality and verticality of the grating ruler 2 after installation, and avoiding measurement errors caused by installation offset. The limiting groove 52 is symmetrically opened on both sides of the top end of the fixing plate 51, and it is engaged with the bottom end of the side cover 4 to limit the lateral displacement of the grating ruler 2 and the side cover 4, ensuring that the grating ruler 2 is on the machine tool slide plate 1. The installation position is precise and stable, preventing displacement during vibration. The multi-layer soft pad 53 is fixed to the rear end of the machine tool slide plate 1 and fits against the front end of the grating ruler 2, directly bearing the vibration transmitted by the machine tool slide plate 1. It absorbs vibration energy through its own elastic deformation, weakening the impact of high-frequency vibration on the grating ruler 2 body. The rear end of the machine tool slide plate 1 and the rear end of the side cover 4 are both provided with screw holes 54, and the two screw holes 54 are coaxial. The screw 55 is set at the rear end of the side cover 4 and is screwed into the screw hole 54 to firmly fix the grating ruler 2 on the machine tool slide plate 1. An anti-loosening washer is provided between the screw 55 and the side cover 4 to prevent the screw from loosening due to processing vibration and ensure connection stability.

[0018] Reference Figure 7 As one embodiment of this utility model, specifically, a slightly deformable Z-shaped rubber pad 531 is fixedly arranged inside the multi-layer soft pad 53. The elastic restoring force of the Z-shaped structure is used to buffer the vibration impact, extend the vibration transmission path, enhance the attenuation effect of high-frequency vibration, and prevent the vibration from directly penetrating the soft pad and being transmitted to the grating ruler. A double-layer rubber pad 532 is fixed inside the Z-shaped rubber pad 531, which works in conjunction with the Z-shaped rubber pad 531 to enhance the absorption and weakening effect of high-frequency vibration.

[0019] Reference Figure 3 , Figure 4 and Figure 5 As one embodiment of this utility model, specifically, the slide rail vibration damping component 6 includes a slide groove 61, a slider 62, an internal elongated pad 63, and an arc-shaped pad 64. The slide groove 61 is symmetrically opened inside the grating ruler 2. The slider 62 is fixed on both sides of the reading head and is slidably connected to the slide groove 61 to ensure that the reading head moves smoothly along the scale direction of the grating ruler 2, providing guidance for high-precision measurement. The internal elongated pad 63 is fixed to the inner wall of the slide groove 61, and the arc-shaped pad 64 is fixed to the end of the slider 62. Its arc-shaped structure can ensure a tight fit with the internal elongated pad 63, and further absorb vibration through elastic deformation to avoid gap fluctuations between the slider 62 and the slide groove 61. The arc-shaped pad 64 slides in close contact with the internal elongated pad 63.

[0020] Reference Figure 6As one embodiment of this utility model, specifically, the adjustable rolling damping assembly 7 includes a side groove 71, a fixed bracket 72, a buffer plate 73, multiple elastic plates 74, layered buffer pads 75, and an adjusting nut 76. The side groove 71 is symmetrically opened on both sides of the slide groove 61, and the fixed bracket 72 is symmetrically fixed on both sides of the slider 62, providing an installation reference for the buffer plate 73, elastic plates 74, layered buffer pads 75, and adjusting nut 76. The buffer plate 73 is sleeved on the end of the fixed bracket 72 and is slidably connected to the fixed bracket 72. The multiple elastic plates 74 are sleeved on the surface of the fixed bracket 72 and are located between the buffer plate 73 and the fixed bracket 72. Between the fixed brackets 72, residual vibration is absorbed by their own elastic deformation. The stacking of multiple elastic plates 74 can enhance the vibration reduction effect. At the same time, the tightness can be adjusted by adjusting the nut 76 to adapt to different vibration intensities. The layered buffer pad 75 is sleeved on the surface of the fixed bracket 72 and is located at the joint between multiple elastic plates 74 to avoid the attenuation of the vibration reduction effect caused by direct rigid contact between the elastic plates 74. At the same time, it further absorbs vibration energy and improves the overall vibration reduction performance. The adjusting nut 76 is tightened and fixed at the end of the fixed bracket 72 and is pressed and adhered to the buffer plate 73. An anti-loosening washer is provided between the adjusting nut 76 and the buffer plate 73.

[0021] Reference Figure 6 As one embodiment of this utility model, specifically, a support 77 is fixed to the end of the buffer plate 73, providing installation space for the circular groove 78 and the universal ball 79, and transmitting the buffering force of the buffer plate 73 to the universal ball 79, ensuring the stable fit between the universal ball 79 and the side groove 71. The end of the support 77 is provided with circular grooves 78 at equal intervals, limiting the movement range of the universal ball 79, ensuring that the universal ball 79 can only roll within the circular groove 78, avoiding falling off or shifting. The universal ball 79 is provided inside the circular groove 78, and the universal ball 79 rolls in contact with the inner wall of the side groove 71, converting the sliding friction between the slider 62 and the groove 61 into rolling friction, greatly reducing movement resistance and wear. At the same time, by tightly fitting with the side groove 71, the stable posture of the reading head is maintained, and the offset caused by residual vibration is counteracted.

[0022] Working principle: When performing high-precision machining on shaft-type workpieces using an old machine tool, a linear encoder 2 needs to be installed on the moving end (slide) of the old machine tool. First, the adjustable rolling vibration damping component 7 is pre-adjusted according to the dimensions. Then, the reading head at the bottom of the sensor 3, along with the slide rail vibration damping component 6 and the adjustable rolling vibration damping component 7, is pushed into the interior of the linear encoder 2 for sliding connection. Next, the linear encoder 2 is installed on the scale platform vibration damping component 5 at the rear end of the machine tool slide 1 through two side covers 4. This allows the high-frequency vibration generated by the machine tool slide 1 during cutting to be pre-intercepted by the scale platform vibration damping component 5 and transmitted to the linear encoder 2 body, preventing the linear encoder 2 from undergoing slight deformation or displacement due to vibration. Furthermore, the reading head of the sensor 3 is always in contact with the slide rail of the linear encoder 2 through the adjustable rolling vibration damping component 7 and the slide rail vibration damping component 6, offsetting the residual vibration after vibration damping of the linear encoder 2. The vibration damping components of the fixed end and the moving end (sensor 3) are used in combination to ensure micron-level measurement accuracy. Therefore, both are indispensable. If only the fixed end of the scale damping component 5 is used, the vibration when the reading head slides will cause fluctuations in the gap between the reading head and the grating ruler 2, resulting in measurement errors. If only the sliding rail damping component 6 and the adjustable rolling damping component 7 are used, the vibration of the machine tool slide plate 1 will be directly transmitted to the grating ruler 2 body, causing the grating ruler 2 scale itself to shift position, which will also cause measurement errors. Only by combining the two can "the grating ruler 2 body is stable + the reading head is in contact with the surface" be achieved, ensuring measurement accuracy. In addition, the metal spring adjustment of the sliding rail damping component 6 can adapt to the small position changes brought about by the scale damping component 5. At the same time, the adjustable rolling damping component 7 reduces sliding friction and avoids wear after long-term operation, so as to achieve the function of vibration damping without jamming, stability and durability.

[0023] Specifically, first use a tool to tighten or loosen the adjusting nut 76, pressing or loosening the buffer plate 73 and the elastic plate 74. Once the support 77 at the end of the buffer plate 73 and the universal ball bearing 79 fit perfectly into the side groove 71, the adjustment is complete. Then, the sensor 3, along with the reading head, slides into the interior of the grating ruler 2, causing the slider 62 to slide into the groove 61, and allowing the built-in long strip pad 63 to fit into the curved pad 64. Simultaneously, the fixed bracket 72, buffer plate 73, elastic plate 74, layered buffer pads 75, adjusting nut 76, support 77, circular groove 78, and universal ball bearing 79 slide into the side groove 71, ensuring smooth rolling of the universal ball bearing 79 into the side groove 71. Finally, the side cover 4 and the grating ruler 2 are connected by screws. After securing the connection, the bottom end of the grating ruler 2 is attached to the top end of the fixing plate 51, and the bottom end of the side cover 4 is engaged with the limiting groove 52. At the same time, the front end of the grating ruler 2 is attached to the screw hole 54. Then, the screw 55 is screwed through the screw hole 54 on the side cover 4 and into the screw hole 54 at the rear end of the machine tool slide plate 1 for a secure connection. This allows the grating ruler 2 to be installed at the rear end of the machine tool slide plate 1. When the machine tool slide plate 1 vibrates during processing, the vibration force is transmitted to the grating ruler 2. Its high-frequency vibration is attenuated once by the multiple layers of soft pads 53 through the internal Z-shaped rubber pad 531 and double-layer rubber pad 532. The remaining minute vibration is transmitted to the grating ruler 2 and then attenuated a second time by the elastic plate 74 and the universal ball 79, thus ensuring the measurement accuracy of the sensor 3.

[0024] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-precision displacement measurement sensor based on hybrid gratings, comprising a grating ruler (2) arranged at the rear end of a machine tool slide (1), characterized in that: It also includes a sensor (3), a side cover (4), a scale vibration damping assembly (5), a slide rail vibration damping assembly (6), and an adjustable rolling vibration damping assembly (7). The sensor (3) is set at the top of the grating ruler (2). The bottom of the sensor (3) is fixed with a reading head that can slide inside the grating ruler (2). The side cover (4) is symmetrically fixed on both sides of the grating ruler (2). The scale vibration damping assembly (5) is fixed at the rear end of the machine tool slide plate (1) and fixedly connected to the grating ruler (2). The slide rail vibration damping assembly (6) is set inside the grating ruler (2) and connected to the reading head of the sensor (3). The adjustable rolling vibration damping assembly (7) is set on both sides of the slide rail vibration damping assembly (6). When the sensor (3) moves laterally, it synchronously drives the slide rail vibration damping assembly (6) and the adjustable rolling vibration damping assembly (7) to move laterally in the same direction through the reading head.

2. The high-precision displacement measurement sensor based on hybrid grating according to claim 1, characterized in that: The vibration damping assembly (5) of the scale platform includes a fixed plate (51), a limiting groove (52), a multi-layer soft pad (53), a screw hole (54), and a screw (55). The fixed plate (51) is fixed to the rear end of the machine tool slide plate (1), and its top end is attached to the bottom end of the grating ruler (2). The limiting groove (52) is symmetrically opened on both sides of the top end of the fixed plate (51), and it is engaged with the bottom end of the side cover (4). The multi-layer soft pad (53) is fixed to the rear end of the machine tool slide plate (1) and attached to the front end of the grating ruler (2). The rear end of the machine tool slide plate (1) and the rear end of the side cover (4) are both provided with screw holes (54), and the two screw holes (54) are coaxial. The screw (55) is set at the rear end of the side cover (4), and it is screwed into the screw hole (54). An anti-loosening washer is provided between the screw (55) and the side cover (4).

3. The high precision displacement measurement sensor based on hybrid grating according to claim 2, characterized in that: The multi-layer soft pad (53) is internally fixed with a slightly deformable Z-shaped rubber pad (531), and the Z-shaped rubber pad (531) is internally fixed with a double-layer rubber pad (532).

4. The high precision displacement measurement sensor based on hybrid grating according to claim 3, characterized in that: The slide rail vibration damping assembly (6) includes a slide groove (61), a slider (62), a built-in elongated pad (63), and an arc-shaped pad (64). The slide groove (61) is symmetrically opened inside the grating ruler (2). The slider (62) is fixed on both sides of the reading head. The slider (62) is slidably connected to the slide groove (61). The built-in elongated pad (63) is fixed on the inner wall of the slide groove (61). The arc-shaped pad (64) is fixed on the end of the slider (62). The arc-shaped pad (64) slides in contact with the built-in elongated pad (63).

5. The hybrid grating based high precision displacement measurement sensor according to claim 4, wherein: The adjustable rolling damping assembly (7) includes a side groove (71), a fixed bracket (72), a buffer plate (73), multiple elastic plates (74), layered buffer pads (75), and an adjusting nut (76). The side groove (71) is symmetrically opened on both sides of the slide groove (61). The fixed bracket (72) is symmetrically fixed on both sides of the slider (62). The buffer plate (73) is sleeved on the end of the fixed bracket (72) and is slidably connected to the fixed bracket (72). The elastic plate (74) is sleeved on the surface of the fixed bracket (72) and is located between the buffer plate (73) and the fixed bracket (72). The layered buffer pad (75) is sleeved on the surface of the fixed bracket (72) and is located at the joint between the multiple elastic plates (74). The adjusting nut (76) is screwed and fixed to the end of the fixed bracket (72) and is pressed and adhered to the buffer plate (73). An anti-loosening gasket is provided between the adjusting nut (76) and the buffer plate (73).

6. The hybrid grating based high precision displacement measurement sensor according to claim 5, wherein: The buffer plate (73) is fixed with a support (77) at its end. The support (77) has circular grooves (78) at equal intervals at its end. Universal ball bearings (79) are provided inside the circular grooves (78). The universal ball bearings (79) roll in contact with the inner wall of the side groove (71).

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