Grating driving structure in a light splitting system and light splitting system

Abstract

The utility model provides a kind of grating drive structure in spectrometer system and spectrometer system belong to grating drive technical field, the device includes stepper motor, harmonic reducer, grating table, grating and zero detector, the drive end of stepper motor is connected with the input end of harmonic reducer, grating table is set on the output end of harmonic reducer, grating table is fixedly connected with grating, grating table is provided with zero detector on the movement path, the complex conversion of rotation-linear-rotation is saved, stepper motor is directly connected with grating table by harmonic reducer, so that the rotational speed of grating is improved several times, the positioning speed of wavelength is improved, harmonic reducer transmission accuracy is high and has no reverse clearance, ensure the accuracy and repeatability of wavelength positioning, and the transmission chain rigidity of device whole is good, no back difference, the rotation error of system is minimal, while the device structure is compact, the number of parts is less, assembly is simple, reduce manufacturing and assembly cost, and harmonic reducer service life is long, maintenance demand is low.

Description

Technical Field

[0001] This utility model relates to the field of grating driving technology, and in particular to a grating driving structure in a beam splitting system. Background Technology

[0002] Atomic absorption spectrophotometers require a grating to rotate to a specific angle (the angle depends on the structure and component dimensions of the spectrophotometer and the grating parameters) to deliver the specific wavelength of the beam separated by the grating to the detector. Grating rotation is typically driven by a stepper motor. However, direct motor drive cannot meet the required accuracy. A mature solution uses a high-precision, high-speed-ratio lead screw with a nut. To ensure the number of motor rotation steps is proportional to the wavelength, a sine arm is also needed. The existing lead screw + sine arm drive structure is relatively mature, but it has some drawbacks: Slow switching speed: The lead screw drive needs to convert the rotational motion of the motor into linear motion, and then into rotational motion through the sine arm. In order to achieve sufficient wavelength resolution, the transmission ratio needs to be designed to be very large, almost reaching 10000:1. Wavelength switching takes a long time (for example, it takes at least one minute to move from ultraviolet wavelength to infrared wavelength).

[0003] Hysteresis issue: During reverse rotation, the lead screw may experience axial movement. Mechanical clearance between the lead screw and nut can cause backlash during forward and reverse rotation, affecting wavelength repeatability and accuracy when the scanning direction changes.

[0004] The trade-off between precision and cost: High-precision lead screws and sine arms are difficult to manufacture and require sophisticated assembly, leading to high overall system costs. Furthermore, length and assembly errors in the sine arm directly cause systemic wavelength errors, resulting in a loss of linearity between the wavelength and the number of motor rotation steps. This necessitates calibration, which not only increases software complexity but also introduces calibration uncertainties and the risk of long-term drift. Utility Model Content

[0005] To address the aforementioned problems, this invention provides a grating driving structure and a beam splitting system in a beam splitting system, thereby resolving the problems existing in the prior art.

[0006] According to a first aspect of the present invention, a grating driving structure is provided in a beam splitting system, including a stepper motor and a harmonic reducer. The driving end of the stepper motor is connected to the input end of the harmonic reducer, and a grating platform is provided on the output end of the harmonic reducer. A grating is fixedly connected to the grating platform.

[0007] As a further embodiment of this utility model, the harmonic reducer is a cup-shaped or cap-shaped harmonic reducer.

[0008] As a further embodiment of this utility model, the harmonic reducer is a harmonic reducer with a reduction ratio of 100:1.

[0009] As a further aspect of this invention, a zero-position detector is provided on the motion path of the grating stage.

[0010] As a further embodiment of this utility model, the stepper motor is a bipolar two-phase hybrid stepper motor with a step angle of no more than 0.9°.

[0011] According to a second aspect of the present invention, a beam splitting system is provided, comprising the grating driving structure of any of the beam splitting systems described above.

[0012] The beneficial effects of this utility model are: 1. This application eliminates the complex conversion between rotation-linear-rotation. The stepper motor is directly connected to the grating stage through a harmonic reducer, which increases the rotational speed of the grating several times and reduces the switching time from ultraviolet (short wavelength) to infrared (long wavelength) to about 10 seconds, thereby improving the wavelength positioning speed. 2. The harmonic reducer has high transmission precision and no backlash, ensuring the accuracy and repeatability of wavelength positioning, and high consistency of wavelength during forward and reverse scanning. 3. Due to the high rigidity and zero hysteresis of the transmission chain, the rotational error of the system is extremely small. This makes the "wavelength-step number" relationship highly correlated, greatly reducing or even eliminating the dependence on complex software calibration, and improving the long-term stability and reliability of the instrument. 4. This device has a compact structure, few parts, and simple assembly, which reduces manufacturing and assembly costs. In addition, the harmonic reducer has a long service life and low maintenance requirements. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural diagram of a grating driving structure in a beam splitting system according to the present invention.

[0014] List of reference numerals in the attached diagram: 1. Stepper motor; 2. Harmonic reducer; 3. Grating stage; 4. Grating; 5. Zero-position detector. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0016] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0017] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0018] Reference Figure 1 The present invention provides a grating driving structure in a beam splitting system, including a stepper motor 1 and a harmonic reducer 2. The driving end of the stepper motor 1 is connected to the input end of the harmonic reducer 2. A grating platform 3 is provided on the output end of the harmonic reducer 2, and a grating 4 is fixedly connected to the grating platform 3.

[0019] Harmonic reducer 2 is a gear transmission mechanism that uses the elastic deformation of a flexible element to transmit power. It uses a flexible, slightly elliptical deformable component (flexible gear) meshing with a rigid component (rigid gear). Under the continuous rotation of the wave generator, staggered tooth motion is generated, achieving a very high reduction ratio (from 30:1 to 320:1) in a very small space. Due to the flexible meshing, the gear teeth are always in close contact with almost no "backlash," resulting in extremely high positioning accuracy. Harmonic reducer 2 includes a flexible gear, a rigid gear, and a harmonic generator. A drive shaft is mounted on the drive end of stepper motor 1, and the drive shaft is fixedly connected to harmonic reducer 2. A grating platform 3 is fixedly connected to the flexible gear, and the rigid gear is fixed to a mounting bracket used to fix harmonic reducer 2. The base is fixedly connected, and the harmonic reducer 2 is a cup-shaped or cap-shaped harmonic reducer. During operation, the stepper motor 1 is directly connected to the grating stage 3 through the harmonic reducer 2, driving the grating stage 3 and the grating 4 on the grating stage 3 to rotate. Due to the characteristics of high reduction ratio, zero backlash, and high torque density of the harmonic reducer 2, the harmonic reducer 2 can subdivide the rotation of the stepper motor 1, so that the minimum rotation angle of the grating 4 can meet the wavelength resolution requirements. With the help of the motor driver, the motor rotation can be subdivided, thereby improving the wavelength resolution. Moreover, by utilizing its zero backlash transmission characteristics, the wavelength can accurately correspond to the number of steps of the stepper motor 1 during forward and reverse rotation, which has obvious advantages when performing wavelength back-and-forth scanning. At the same time, it can greatly increase the rotation speed of the grating 4, thereby improving the working efficiency of the device.

[0020] A flange is provided on the bottom surface of the grating stage 3. The flexible wheel is fixedly connected to the flange of the grating stage 3 by screws. The grating 4 is fixed on the grating stage 3 by a pressure plate. When installing the grating 4, it is necessary to ensure that the working plane of the grating 4 is located at the axis of the rotation of the grating stage 3. By adjusting the horizontal plane of the grating stage 3, the output beam direction is correct. Correspondingly, a light-blocking plate is provided on the grating stage (3). A zero-position detector 5 is provided on the movement path of the grating stage 3. The zero-position detector 5 includes a photoelectric sensor and a mounting bracket. The photoelectric sensor is fixedly connected to the mounting bracket, and the mounting bracket is set on the mounting carrier.

[0021] A grating driving structure in a beam splitting system further includes a driver for driving a stepper motor 1, and the control method of the driver includes the following steps: Initialization: Drive stepper motor 1 to rotate grating stage 3 until triggering photoelectric sensor of zero position detector 5, set this position as mechanical zero position, scan backward from mechanical zero position until find main 0 pole spectrum, corresponding to 0nm position, i.e. optical zero position, wavelength positioning is based on this zero position.

[0022] Wavelength positioning: There is a strict functional relationship f(λ) between the target wavelength λ and the total number of steps N that stepper motor 1 needs to take. f(λ) is related to the monochromator configuration, component installation position and grating parameters.

[0023] Drive execution: The controller calculates the angle that the grating 4 needs to deflect relative to the optical zero position based on f(λ), and then converts the angle into the number of steps N of the stepper motor 1. It sends the corresponding number of pulses to the driver of the stepper motor 1, and the stepper motor 1 drives the grating 4 to rotate precisely to the target angle through the harmonic reducer 2.

[0024] Stepper motor 1 is a bipolar two-phase hybrid stepper motor with a step angle of no more than 0.9°. Harmonic reducer 2 is a harmonic reducer with a reduction ratio of 100:1. Stepper motor 1 has a step angle of 0.9°. After passing through the 100:1 harmonic reducer 2, the single-step resolution of the drive shaft is 0.9° / 100 = 0.009° (32.4 arcseconds). According to the grating equation, this resolution is sufficient to achieve a wavelength positioning accuracy better than 0.1nm. Stepper motor 1 can be micro-step controlled by a driver to rotate to smaller micro-steps, thereby achieving higher positioning accuracy.

[0025] Compared to existing technologies, this application eliminates the complex rotation-linear-rotation conversion. The stepper motor 1 is directly connected to the grating stage 3 via the harmonic reducer 2, which increases the rotational speed of the grating 4 several times. The switching time from ultraviolet (short wavelength) to infrared (long wavelength) is reduced to about 10 seconds, improving the wavelength positioning speed. The harmonic reducer 2 has high transmission precision and no backlash, ensuring the accuracy and repeatability of wavelength positioning. The wavelength consistency is high during forward and reverse scanning. Due to the good rigidity and no backlash of the transmission chain, the rotational error of the system is extremely small. This makes the "wavelength-step number" relationship highly correlated, greatly reducing or even eliminating the dependence on complex software correction, and improving the long-term stability and reliability of the instrument. This device has a compact structure, fewer parts, and simple assembly, reducing manufacturing and assembly costs. Furthermore, the harmonic reducer has a long lifespan and low maintenance requirements.

[0026] It should be noted that not all steps and modules in the above processes and system structure diagrams are mandatory; some steps or modules can be omitted as needed. The execution order of each step is not fixed and can be adjusted as required. The system structure described in the above embodiments can be a physical structure or a logical structure. That is, some modules may be implemented by the same physical entity, or some modules may be implemented by multiple physical entities, or they may be jointly implemented by certain components in multiple independent devices.

[0027] In the above embodiments, the hardware modules can be implemented mechanically or electrically. The present invention has been described and illustrated in detail above with reference to the accompanying drawings and preferred embodiments. However, the present invention is not limited to these disclosed embodiments. Based on the above embodiments, those skilled in the art will understand that more embodiments of the present invention can be obtained by combining the code review methods in the different embodiments described above, and these embodiments are also within the protection scope of the present invention.

Claims

1. A grating driving structure in a beam splitting system, characterized in that, It includes a stepper motor (1) and a harmonic reducer (2). The driving end of the stepper motor (1) is connected to the input end of the harmonic reducer (2). A grating platform (3) is provided on the output end of the harmonic reducer (2). A grating (4) is fixedly connected on the grating platform (3).

2. The grating driving structure in a beam splitting system according to claim 1, characterized in that, The harmonic reducer (2) is a cup-shaped or cap-shaped harmonic reducer.

3. The grating driving structure in a beam splitting system according to claim 1, characterized in that, The harmonic reducer (2) is a harmonic reducer with a reduction ratio of 100:

1.

4. The grating driving structure in a beam splitting system according to claim 1, characterized in that, A zero-position detector (5) is set on the motion path of the grating stage (3).

5. The grating driving structure in a beam splitting system according to claim 1, characterized in that, The stepper motor (1) is a bipolar two-phase hybrid stepper motor with a step angle of no more than 0.9°.

6. A spectroscopic system, characterized in that, It includes a grating driving structure in a beam splitting system as described in any one of claims 1-5.

Images