X-ray diffractometer support arm counterweight adjustment method and adjustment system

Abstract

This invention discloses a method and system for adjusting the counterweight of an X-ray diffractometer's support arm. The method includes: controlling a drive motor to drive the support arm to rotate unidirectionally at a constant speed during scanning; acquiring the real-time drive current curve of the drive motor during the unidirectional uniform speed rotation scan; obtaining the effective data range when the drive motor is under maximum load and continuously outputs high power based on the real-time drive current curve; fitting and generating a partial cosine curve with DC bias based on the data within the effective data range; obtaining the corresponding current amplitude and phase based on the partial cosine curve; and adjusting the connection position between the support arm and the counterweight arm and the installation position of the counterweight based on the current amplitude and phase. The support arm counterweight adjustment method of this invention improves the accuracy of unbalanced torque calculation, and the calculation process is simple and easy to implement.

Description

Technical Field

[0001] This invention relates to the field of X-ray detection technology, and more particularly to a method for adjusting the counterweight of the support arm of an X-ray diffractometer and a system for adjusting the counterweight of the support arm of an X-ray diffractometer applicable to the method. Background Technology

[0002] X-ray diffractometer (XRD) is used to analyze the crystal structure and phase composition of materials. Its working principle is based on Bragg's law. When X-rays are incident on a sample, constructive interference occurs on the crystal planes that satisfy Bragg's law, producing diffraction peaks. By scanning and recording the diffraction intensity at different angles, a spectrum is generated, and the structural information of the material (phase, cell parameters, grain size, etc.) can be analyzed.

[0003] In the goniometer of an X-ray diffractometer (XRD), the X-ray source and detector are usually mounted on rotating goniometer support arms to support their rotation. Due to the significant weight of the X-ray tube, detector, and goniometer support arms, if the center of gravity deviates from the axis of rotation, a gravitational torque will be generated, leading to a torque imbalance. When the X-ray source or detector rotates, the drive motor needs to output additional torque to overcome the eccentric torque caused by gravity, i.e., the gravitational torque. This increases the load on the drive motor to keep the X-ray source or detector stationary or rotating at a constant speed. This prevents the X-ray source or detector from rotating on its own due to the gravitational torque when stopped, and also prevents vibration or thermal drift from occurring when rotating at a constant speed to detect the sample, thus reducing the accuracy of sample detection.

[0004] In related technologies, a counterweight is installed on the goniometer support arm to generate a gravitational torque equal in magnitude but opposite in direction to the gravitational torque of the X-ray source or detector. This aims to achieve a certain degree of gravitational torque balance, making the total system torque zero, thereby eliminating the rotational tendency caused by its own weight and ensuring the measurement accuracy and mechanical stability of the X-ray diffractometer. However, in modern high-end X-ray diffractometers (such as those with a nominal angular measurement accuracy of 0.0001°), using a fixed counterweight or only providing a few sets of roughly stepped mounting holes cannot achieve high-precision counterweighting. This means that precise adjustment of torque balance cannot be achieved, and the minute torque imbalance caused by the static friction of the transmission system cannot be detected by conventional manual physical leveling methods (observing for any rotational tendency). In other words, the frictional torque masks the minute gravitational torque imbalance, resulting in insufficient torque balance accuracy and room for improvement. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for adjusting the counterweight of the support arm of an X-ray diffractometer. This method overcomes the torque calculation errors caused by asymmetric forward and reverse friction forces, backlash, and nonlinear reverse drive characteristics under downhill conditions when using non-self-locking or weakly self-locking transmission mechanisms (such as worm gears and harmonic reducers). This improves the accuracy of unbalanced torque calculation, simplifies the calculation process, and is easy to implement.

[0006] According to an embodiment of the present invention, an X-ray diffractometer support arm counterweight adjustment method is provided. The X-ray diffractometer includes a detection module and a drive motor. The detection module is mounted on the support arm, and the drive motor drives the support arm to rotate, thereby rotating the detection module. The support arm is connected to a counterweight arm that rotates coaxially and has an adjustable connection position. The counterweight arm is equipped with an adjustable counterweight component. The support arm counterweight adjustment method includes: The drive motor is controlled to drive the support arm to rotate unidirectionally at a constant speed for scanning. Obtain the real-time drive current curve of the drive motor during unidirectional uniform rotation scanning; Based on the real-time drive current curve, obtain the effective data range of the drive motor at its maximum load state; Based on the data within the effective data range, a partial cosine curve with DC bias is fitted and generated. Based on the aforementioned partial cosine curve, the corresponding current amplitude and phase are obtained; The connection position between the support arm and the counterweight arm, and the installation position of the counterweight are adjusted according to the current amplitude and the phase.

[0007] The X-ray diffractometer support arm counterweight adjustment method according to embodiments of the present invention simplifies the calculation process by selecting the clearest and most linear region of the physical model for mathematical calculation, eliminating the need to consider the complex issues of whether the transmission mechanism is self-locking in the downhill section of the system. Unidirectional rotation scanning ensures that the gaps of all transmission mechanisms are compressed to one side, eliminating the phase drift caused by the forward and reverse return gaps from the root. This overcomes the torque calculation errors caused by the asymmetry of forward and reverse friction, return gaps, and nonlinear reverse drive characteristics in the downhill state when using non-self-locking or weakly self-locking transmission mechanisms (such as worm gears and harmonic reducers), thereby improving the accuracy of unbalanced torque calculation.

[0008] According to some embodiments of the present invention, the method for adjusting the counterweight of the support arm of an X-ray diffractometer, wherein obtaining the real-time drive current curve of the drive motor during unidirectional uniform speed rotation scanning includes: During the forward uniform speed rotation scanning process of the support arm, the forward real-time attitude angle and the corresponding forward real-time drive current fed back by the drive motor are obtained at a fixed frequency, and a forward real-time drive current curve is generated based on the forward real-time attitude angle and the forward real-time drive current. Alternatively, during the reverse uniform rotation scanning process of the support arm, the reverse real-time attitude angle and the corresponding reverse real-time drive current fed back by the drive motor are obtained at a fixed frequency, and a reverse real-time drive current curve is generated based on the reverse real-time attitude angle and the reverse real-time drive current.

[0009] According to some embodiments of the present invention, the method for adjusting the counterweight of the support arm of an X-ray diffractometer, wherein obtaining the effective data range of the drive motor at its maximum load state based on the real-time drive current curve includes: The real-time drive current curve is filtered by moving average to obtain the maximum current point and the angle corresponding to the maximum current point. Using the angle corresponding to the maximum current point as the center, extract the effective data range to both sides.

[0010] According to some embodiments of the present invention, the method for adjusting the counterweight of the support arm of an X-ray diffractometer, wherein fitting and generating a partial cosine curve with DC bias based on data within the effective data range includes: Based on the first calculation formula, the data within the effective data range are fitted to generate a partial cosine curve with DC bias. The first calculation formula is: , For equivalent constant triboelectric current, For the equivalent current amplitude of the unbalanced gravitational torque, θ max For phase, It is a partial cosine curve.

[0011] According to some embodiments of the present invention, the method for adjusting the counterweight of the support arm of an X-ray diffractometer, wherein obtaining the corresponding current amplitude and phase based on the partial cosine curve includes: The data within the effective data range are used to extract the fundamental frequency feature components using constrained least squares or machine learning / Fourier transform, and the current amplitude and phase are extracted based on the first calculation formula.

[0012] According to some embodiments of the present invention, the method for adjusting the counterweight of the support arm of an X-ray diffractometer, wherein adjusting the connection position of the support arm and the counterweight arm and the installation position of the counterweight according to the current amplitude and the phase includes: Based on the calibrated system comprehensive mapping coefficients, the current amplitude and the phase are mapped to a first mechanical adjustment amount and a second mechanical adjustment amount; The support arm and the counterweight arm are detachably connected via holes corresponding to the first mechanical adjustment amount; Furthermore, the counterweight and the counterweight arm are detachably connected via holes corresponding to the second mechanical adjustment amount.

[0013] According to some embodiments of the present invention, the system comprehensive mapping coefficient is obtained by a vector incremental calibration method, which includes: Record the first eigenvector in the current unbalanced state. ; At the known lever arm position of the support arm, a mass of m is mounted. sd Standard test weights; The process involves performing steps such as adjusting the connection position between the support arm and the counterweight arm and the installation position of the counterweight based on the current amplitude and phase, to obtain the second feature vector after the standard test weight is mounted. ; The first feature vector and the second feature vector are subjected to vector difference operation in polar coordinates based on the second calculation formula, and the system comprehensive mapping coefficient K is obtained based on the third calculation formula. uphill ; The second calculation formula is as follows: The third calculation formula is: ΔA is A1-A0, g is the acceleration due to gravity, and m sd For the mass of the standard test weight, r std Given the position of the lever arm, K uphill These are the system comprehensive mapping coefficients.

[0014] According to some embodiments of the present invention, the method for adjusting the counterweight of the support arm of an X-ray diffractometer, wherein mapping the current amplitude and the phase to a first mechanical adjustment amount and a second mechanical adjustment amount based on a calibrated system comprehensive mapping coefficient includes: Obtain the current imbalance vector, the , The amplitude of the current is currently stated. The phase currently described; Based on the current unbalance vector, the true unbalance torque is obtained using the fourth calculation formula, which is: M unb For a real unbalanced torque, K uphill These are the system comprehensive mapping coefficients; Based on the actual unbalanced torque, the radial movement distance of the counterweight is output.

[0015] According to some embodiments of the present invention, the method for adjusting the counterweight of an X-ray diffractometer support arm, wherein outputting the radial movement distance of the counterweight based on the actual unbalanced torque includes: The radial movement distance of the counterweight is output based on the fifth calculation formula, which is: m block Let g be the mass of the counterweight, g be the acceleration due to gravity, and ΔL be the radial distance the counterweight moves.

[0016] According to some embodiments of the present invention, the method for adjusting the counterweight of the support arm of an X-ray diffractometer, wherein mapping the current amplitude and the phase to a first mechanical adjustment amount and a second mechanical adjustment amount based on a calibrated system comprehensive mapping coefficient includes: Obtain the current imbalance vector, the , The amplitude of the current is currently stated. The phase currently described; The rotation angle of the counterweight arm is output based on the current imbalance vector.

[0017] According to some embodiments of the present invention, the support arm counterweight adjustment method of an X-ray diffractometer is provided, wherein the first mechanical adjustment amount is the connection angle between the support arm and the counterweight arm, and the first mechanical adjustment command is configured to adjust the connection angle according to the phase to adjust the gravity lever arm angle of the counterweight to compensate for the phase deviation of the unbalanced gravity torque generated during the rotation of the detection module. The second mechanical adjustment amount is the radial distance of the counterweight on the counterweight arm. The second mechanical adjustment command is configured to adjust the radial distance according to the current amplitude to adjust the length of the gravity arm of the counterweight to compensate for the amplitude deviation of the unbalanced gravitational torque generated during the rotation of the detection module.

[0018] According to some embodiments of the present invention, the center of mass of the counterweight, the center of mass of the counterweight arm, and the axis of rotation of the support arm are collinear. The holes corresponding to the first mechanical adjustment amount are arranged in a circle around the axis of rotation of the support arm, and the holes corresponding to the second mechanical adjustment amount are arranged in a direction parallel to the line connecting the center of mass of the counterweight and the axis of rotation of the support arm.

[0019] The present invention also proposes a counterweight adjustment system for the support arm of an X-ray diffractometer.

[0020] The support arm counterweight adjustment system of the X-ray diffractometer according to the embodiments of the present invention is applicable to the support arm counterweight adjustment method of the X-ray diffractometer described in any of the above embodiments.

[0021] The X-ray diffractometer support arm counterweight adjustment system according to embodiments of the present invention, by applying the above-described X-ray diffractometer support arm counterweight adjustment method, can improve the calculation accuracy of unbalanced torque, improve torque balancing accuracy, and achieve gravitational torque balance, thereby improving the overall performance of the X-ray diffractometer and effectively improving detection accuracy.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of an X-ray diffractometer according to an embodiment of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of an X-ray diffractometer according to an embodiment of the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the structure of an X-ray diffractometer according to an embodiment of the present invention. Figure 3 ; Figure 4 This is a schematic diagram of the structure of the first support arm according to an embodiment of the present invention; Figure 5 This is a partial structural diagram of an X-ray diffractometer according to an embodiment of the present invention. Figure 1 ; Figure 6 This is a partial structural diagram of an X-ray diffractometer according to an embodiment of the present invention. Figure 2 ; Figure 7 This is a schematic diagram of the counterweight adjustment method for the support arm of an X-ray diffractometer according to an embodiment of the present invention.

[0024] Figure label: X-ray diffractometer 100, Detection module 1, first detection module 11, second detection module 12, Support arm 2, first support arm 21, first connecting hole 211, second support arm 22, Counterweight arm 3, first counterweight arm 31, connecting arc rod 311, first adjusting hole 3111, second adjusting hole 312, second counterweight arm 32. Counterweight 4, first counterweight 41, mounting slot 411, second connecting hole 4111, second counterweight 42. Rotation axis 5, Link 6, first link 61, second link 62. First connector 71, second connector 72 The center of mass of the first support arm is 81, the center of mass of the first detection module is 82, the center of mass of the rotating shaft is 83, the center of mass of the first counterweight arm is 84, and the center of mass of the first counterweight is 85. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 invention based on the specific circumstances.

[0027] The following is for reference. Figures 1-7 This invention describes a method for adjusting the counterweight of the support arm of an X-ray diffractometer according to an embodiment of the present invention. This method overcomes the torque calculation errors caused by asymmetry of forward and reverse friction, backlash, and nonlinear reverse drive characteristics under downhill conditions when using non-self-locking or weakly self-locking transmission mechanisms (such as worm gears and harmonic reducers). This improves the accuracy of unbalanced torque calculation, simplifies the calculation process, and is easy to implement.

[0028] like Figures 1-7 As shown, according to an embodiment of the present invention, the X-ray diffractometer includes a detection module 1 and a drive motor. The detection module 1 is installed on the support arm 2. The drive motor is used to drive the support arm 2 to rotate so as to drive the detection module 1 to rotate. The support arm 2 is connected to a counterweight arm 3 that rotates along the same axis and whose connection position is adjustable. The counterweight arm 3 is equipped with a counterweight component 4 whose position is adjustable.

[0029] Specifically, the detection module 1 is used to detect the sample. The detection module 1 includes a first detection module 11 and a second detection module 12. The first detection module 11 is a radiation source, and the second detection module 12 is a detector. The radiation source is used to generate X-rays of a specific wavelength. The X-rays can irradiate the sample at a certain angle (such as angle θ). The sample can be fixed on the sample stage. The crystal structure of the sample causes the X-rays to diffract. The detector is used to receive the diffracted X-rays. The detector can scan and move synchronously in different angular directions (such as angle θ) to detect the intensity of the diffracted X-rays that conform to the Bragg equation and receive the X-rays diffracted from the sample. The weak X-ray photons are converted into electrical signals, thereby achieving accurate capture of low-intensity signals, that is, capturing the diffraction signals generated by the sample. The principle described here is that the sample is fixed, and the X-ray source and detector rotate in opposite directions with the same angular velocity θ. The rotation axes of the X-ray source and detector are the same, both rotating around the rotation axis 5 (where the sample is located), that is, detection is achieved in θ / θ mode. Of course, it can also be set up so that the X-ray source is fixed, the sample rotates by an angle θ, and the detector rotates by an angle 2θ in the same direction. The rotation axes of the sample and detector are the same, both rotating around the rotation axis 5 (where the sample is located), that is, detection is achieved in θ-2θ mode, which can be applied to the detection of different samples.

[0030] The drive motor serves as the power source, providing power to drive the detection module 1 to rotate. The X-ray source and detector can share a single drive motor, connected via a linkage mechanism to drive each independently. Alternatively, each X-ray source and detector can be equipped with a separate drive motor: a first drive motor for the X-ray source and a second drive motor for the detector. The first and second drive motors are connected to the X-ray source and detector respectively, driving each independently. In other words, the first detection module 11 can be driven to rotate by the first drive motor, and the second detection module 12 can rotate by the second drive motor.

[0031] In practical design, the drive motor can be set as a servo motor, a direct drive motor (DD motor), a DC motor, etc. Direct drive motors (DD motors) and DC motors can be directly driven, while servo motors need to be reduced in speed through a reduction mechanism (such as a worm gear structure or a harmonic reducer).

[0032] Support arm 2 is used to support and fix the detection module 1, such as Figure 1 As shown, the support arm 2 may include a first support arm 21 and a second support arm 22. The first support arm 21 is used to support and fix the first detection module 11, i.e., the X-ray source, and the second support arm 22 is used to support and fix the second detection module 12, i.e., the detector. That is, the X-ray source can be fixedly mounted on the first support arm 21, and the detector can be fixedly mounted on the second support arm 22 to achieve the fixation of the X-ray source and the detector and ensure the stability of the X-ray source and the detector. The X-ray diffractometer 100 also includes a goniometer disk. The first support arm 21 and the second support arm 22 can be fixedly connected to two goniometer disks respectively to achieve relative rotation of the first support arm 21 and the second support arm 22. Thus, when the drive motor drives the support arm 2 to rotate, the support arm 2 can drive the detection module 1 to rotate. That is, the first drive motor drives the first support arm 21 to rotate to drive the first detection module 11 (X-ray source) to rotate, and the second drive motor drives the second support arm 22 to rotate to drive the second detection module 12 (detector) to rotate.

[0033] The support arm 2 can be connected to the counterweight arm 3 via the connecting rod 6, so that the support arm 2, connecting rod 6, and counterweight arm 3 form a single integrated structure. The counterweight arm 3 can rotate around the rotation axis 5, that is, the support arm 2 and the counterweight arm 3 rotate around the same axis (the axis of rotation axis 5), and the connection position between the counterweight arm 3 and the support arm 2 is adjustable. The counterweight arm 3 is also equipped with a counterweight 4, and the installation position of the counterweight 4 on the counterweight arm 3 is adjustable. Specifically, as shown... Figure 2 As shown, the first support arm 21 can be connected to the first counterweight arm 31 via the first connecting rod 61, and the second support arm 22 can be connected to the second counterweight arm 32 via the second connecting rod 62. The first support arm 21, the second support arm 22, the first counterweight arm 31, and the second counterweight arm 32 all rotate around the rotation axis 5. The first counterweight arm 31 is equipped with a first counterweight 41, and the mounting position of the first counterweight 41 on the first counterweight arm 31 is adjustable. The second counterweight arm 32 is equipped with a second counterweight 42, and the mounting position of the second counterweight 42 on the second counterweight arm 32 is adjustable. Because the detection module 1 and the support arm 2 themselves have a large self-weight, if the center of gravity deviates from the rotation axis 5, a gravitational torque will be generated, leading to torque imbalance and increasing the load on the drive motor.

[0034] Therefore, by adjusting the installation position of the counterweight 4 on the counterweight arm 3 and adjusting the connection position of the support arm 2 and the counterweight arm 3, the torque balance of the detection module 1 can be achieved. In other words, it is necessary to adjust the installation position of the first counterweight 41 on the first counterweight arm 31 and adjust the connection position of the first support arm 21 and the first counterweight arm 31 to achieve the torque balance of the radiation source. It is also necessary to adjust the installation position of the second counterweight 42 on the second counterweight arm 32 and adjust the connection position of the second support arm 22 and the second counterweight arm 32 to achieve the torque balance of the detector.

[0035] In practice, both the radiation source and the detector need to achieve torque balance. The torque balancing principle is the same for both. The following explanation will take the radiation source as an example. It is understandable that the existence of gravitational torque causes the first drive motor to bear additional force, thus increasing the load on the first drive motor. Furthermore, when the radiation source and the first support arm 21 rotate together in different postures (i.e., rotate to different angular positions), the gravitational torque changes. The gravitational torque is determined by the product of gravity (mg: m is the total mass of the radiation source and the first support arm 21) and the lever arm (L: the vertical distance from the line of action of gravity to the center of rotation). When the total center of mass of the first support arm 21 and the radiation source is vertically upward or downward, the line of action of gravity passes through the rotation axis, the gravitational lever arm is zero, and the total gravitational torque is minimum and zero. At this time, no rotational effect occurs. When the total center of mass of the first support arm 21 and the radiation source rotates to a horizontal position, the vertical distance between the line of action of gravity and the rotation axis is greatest, and the total gravitational torque is maximum. In other words, the magnitude of the gravitational torque changes with the rotation angle of the first support arm 21. Therefore, a first counterweight arm 31 and a first counterweight component 41 are provided for the first support arm 21 to balance the gravitational torque.

[0036] The principle by which the X-ray source and the first support arm 21 balance the gravitational torque is as follows: First, the torque relationship between the first support arm 21, the radiation source, the first counterweight arm 31, and the first counterweight 41 is as follows:

[0037] in, , , , These are the center-of-mass positions of the first support arm 21, the radiation source, the first counterweight arm 31, and the first counterweight 41, respectively. , , , The force vectors at the center of mass of the first support arm 21, the radiation source, the first counterweight arm 31, and the first counterweight 41 are respectively.

[0038] Secondly, considering that the forces that need to be excluded from influence are mainly the gravity borne by the first support arm 21, the first counterweight arm 31, the radiation source, and the first counterweight 41, then:

[0039] Among them, reference appendix Figure 4 As shown, , , , These are the center-of-mass positions of the first support arm 21, the radiation source, the first counterweight arm 31, and the first counterweight 41, respectively. , , , These refer to the masses of the first support arm 21, the radiation source, the first counterweight arm 31, and the first counterweight 41, respectively. Let be the rotation axis position vector of the first support arm 21.

[0040] like Figure 4 As shown, in order to achieve gravitational torque balance, i.e., to counteract the gravitational torque generated by the radiation source and the first support arm 21, it is necessary to make the center of mass of the first counterweight arm 31, the center of mass of the first counterweight 41, and the axis of rotation 5 collinear. Therefore:

[0041]

[0042] in, The distance between the center of mass of the first support arm 21 and the center of the rotation axis. The distance between the projection of the center of mass of the radiation source onto the lever arm of the first support arm 21 and the axis of rotation is given. The distance between the radiation source and the lever arm of the first support arm 21. , , , These refer to the masses of the first support arm 21, the radiation source, the first counterweight arm 31, and the first counterweight 41, respectively. , These are the distances between the center of mass of the first counterweight arm 31 and the center of the rotating shaft, respectively. The angle between the straight line containing the first counterweight arm 31, the first counterweight component 41, and the axis of rotation and the lever arm of the first support arm 21.

[0043] The above explains the principle of balancing torque. To address this structural torque balancing, this application proposes the following design: Figures 1-4 As shown, one end of the first counterweight arm 31 is provided with a connecting arc rod 311. The connecting arc rod 311 is provided with a plurality of first adjustment holes 3111 distributed circumferentially. The end of the first connecting rod 61 away from the first support arm 21 is connected to the connecting arc rod 311 through the first adjustment holes 3111. By adjusting the connection position of the first connecting rod 61 and the first adjustment holes 3111, that is, by connecting the first connecting rod 61 to the first adjustment holes 3111 at different positions, the angle between the straight line containing the first counterweight arm 31, the first counterweight 41 and the axis of rotation and the lever arm of the first support arm 21 can be adjusted. The size of the first counterweight arm 31 is determined by two sets of circumferentially distributed second adjustment holes 312. Each set of second adjustment holes 312 includes multiple radially spaced second adjustment holes 312. The first counterweight 41 can be installed on the first counterweight arm 31 through the second adjustment holes 312. By adjusting the connection position between the first counterweight 41 and the second adjustment holes 312, that is, by connecting the first counterweight 41 to the first adjustment holes 3111 at different positions, the distance between the center of mass of the first counterweight arm 31 and the center of rotation axis can be adjusted, i.e., the distance between the center of mass of the first counterweight arm 31 and the first counterweight 41 and the axis of rotation can be adjusted. , The size of the first counterweight 41 and the first counterweight arm 31 is determined by the setting of two sets of second adjustment holes 312, which ensures a stable and reliable connection between the first counterweight 41 and the first counterweight arm 31.

[0044] Therefore, the adjustment can be achieved through the first adjustment hole 3111 and the second adjustment hole 312. , , The adjustment, as can be understood, should involve multiple first adjustment holes 3111 distributed around the axis of rotation, i.e., spaced apart circumferentially, so that adjustment can be made through the first adjustment holes 3111 at different positions. The second adjustment hole 312 should be arranged along or parallel to the line connecting the center of mass of the first counterweight arm 31 and the center of mass of the first counterweight 41, that is, distributed radially at intervals.

[0045] Through the above structural design, when the position of the radiation source needs to be adjusted, i.e. Adjust accordingly when changes occur. and This will allow the first support arm 21 to regain its counterweight balance.

[0046] Specifically, multiple commonly used functions can be set for different scenarios. Values, and then for each A set of corresponding adjustment hole positions is set (i.e., the first adjustment hole 3111 and the second adjustment hole 312):

[0047]

[0048] Thus, the X-ray diffractometer 100 needs to be adjusted in different application scenarios. When calculating values, you can use a table lookup method to understand each... The first adjustment hole 3111 and the second adjustment hole 312 are corresponding to the values, and the first connecting rod 61 can be connected to the corresponding first adjustment hole 3111, and the first counterweight 41 can be installed at the corresponding second adjustment hole 312 to achieve the current torque balance. The number of first adjustment holes 3111 and second adjustment holes 312 can be large to increase the adjustment accuracy and improve the torque balance accuracy.

[0049] In actual adjustment, the brake on the first support arm 21 can be disengaged, i.e., the mechanical locking device used to fix or restrict the rotation of the first support arm 21 can be released, allowing the first support arm 21 to rotate freely under the drive of the first drive motor. This brings the first support arm 21 to an approximately horizontal state. Then, try selecting a set of first adjustment holes 3111 and second adjustment holes 312 to bring the first support arm 21 to a torque balance state (i.e., no tendency to rotate). This set of first adjustment holes 3111 and second adjustment holes 312 is the current adjustment method. value corresponding and .

[0050] The torque balancing principle of the detector is the same as that of the X-ray source, and will not be elaborated here.

[0051] Therefore, compared with the prior art, which uses a fixed counterweight or only provides a few sets of rough stepped mounting holes, the installation position of the counterweight 4 on the counterweight arm 3 of this application is adjustable, the connection position between the detection module 1 and the counterweight arm 3 is adjustable, and the adjustment accuracy is higher, which can improve the torque balance accuracy.

[0052] Furthermore, due to measurement and assembly errors in the mass of the first support arm 21, the mass of the first counterweight 41, and the distances from the first adjusting hole 3111 and the second adjusting hole 312 to the axis of rotation, therefore, as Figure 5 and Figure 6As shown, a long strip-shaped first connecting hole 211 can also be provided on the first support arm 21. One end of the first connecting rod 61 connected to the radiation source can be inserted through the first connecting hole 211 by the first connecting piece 71 to realize the connection between the first connecting rod 61 and the radiation source. The other end of the first connecting rod 61 can be fixedly connected to the first adjusting hole 3111, and the position of the first connecting piece 71 in the first connecting hole 211 can be finely adjusted, thereby absorbing assembly errors and improving the assembly convenience of the first connecting rod 61 and the first support arm 21. A mounting groove 411 can also be provided on the first counterweight 41. The mounting groove 411 can be constructed as a rectangular groove, serving as the mounting location for the first counterweight 41 on the first counterweight arm 31. The bottom wall of the mounting groove 411 can have an elongated second connecting hole 4111. The second connecting member 72 can be sequentially inserted into the second connecting hole 4111 and the second adjusting hole 312 to realize the installation of the first counterweight 41 on the first counterweight arm 31. The position of the second connecting member 72 in the second connecting hole 4111 can be finely adjusted, thereby further improving the adjustment accuracy of torque balancing and further improving the balancing accuracy. A fine-tuning bidirectional lead screw or gear rack fine-tuning mechanism can also be additionally provided to further facilitate the adjustment of the mounting position of the first counterweight 41 on the first counterweight arm 31 and to facilitate the fixing of the first counterweight 41, improving assembly convenience and further improving the balancing accuracy.

[0053] In some specific embodiments, such as Figures 1-4 As shown, the first adjustment hole 3111 can be constructed as a circular hole or as an elongated hole extending circumferentially along the connecting arc rod 311 (not shown in the figure). The end of the first connecting rod 61 away from the first support arm 21 can be located in the elongated hole and can move in the elongated hole to finely adjust the connection position of the first connecting rod 61 and the connecting arc rod 311, thereby realizing continuous fine adjustment of the connection position of the first counterweight arm 31 and the first support arm 21, that is, realizing continuous fine adjustment of the angle between the straight line containing the first counterweight arm 31, the first counterweight 41 and the axis of rotation and the lever arm of the first support arm 21. The size can be adjusted to further improve the adjustment accuracy.

[0054] However, the torque counterweight achieved through the above-mentioned structure, such as the traditional manual physical leveling method (observing whether there is a rotation trend), cannot detect the small torque imbalance caused by the static friction of the transmission system. That is, the small torque is not effectively balanced, and the torque balance accuracy cannot be improved.

[0055] Furthermore, for high-precision X-ray diffractometers, the goniometer typically uses a transmission mechanism (such as a worm gear or harmonic reducer), which reduces the driving efficiency and introduces asymmetry in the forward driving efficiency. If this asymmetry is ignored, the unbalanced torque amplitude calculated by the system will be distorted by a fixed proportion, thus affecting the accuracy of the system's counterweight. In addition, the return clearance and the nonlinear reverse drive characteristics under downhill conditions will also cause torque calculation errors, affecting the accuracy of the system's counterweight.

[0056] Therefore, in order to overcome the torque calculation errors caused by the asymmetry of forward and reverse friction, backlash, and nonlinear reverse drive characteristics under downhill conditions when using non-self-locking or weakly self-locking transmission mechanisms (such as worm gears and harmonic reducers), this application proposes a counterweight adjustment method for the support arm 2 of the X-ray diffractometer 100, so that the system can calculate the true unbalanced torque, improve the calculation accuracy of the unbalanced torque, and thus improve the torque balancing accuracy.

[0057] It is understandable that the forward drive efficiency referred to here is the work done by the drive motor as the drive source to overcome the gravitational torque during the rotation of the support arm 2, so that the support arm 2 is lifted and rotated. The reverse drive efficiency refers to the work done by the gravitational torque as the power source, pulling the support arm 2 down and dragging the drive motor to rotate. That is, in the direction of increasing gravitational torque (uphill section, i.e., forward drive), the drive motor must actively output torque to overcome the increasing gravity. In the direction of decreasing gravitational torque (downhill section, i.e., reverse drive), the gravitational torque drives the support arm 2 to rotate and drags the drive motor to rotate. The losses of forward drive efficiency and reverse drive efficiency are completely different. Moreover, due to the non-self-locking design or the relatively weak self-locking, it may not be possible to maintain stillness in reverse, requiring the drive motor to continuously output torque to counteract the gravitational torque. In addition, the friction of the transmission mechanism is different in forward drive and reverse drive, so the forward drive efficiency and reverse drive efficiency are asymmetrical. Furthermore, in the transmission structure, there is a transmission gap between gears. When the drive motor reverses direction or the force direction changes due to gravity, the gear surfaces temporarily disengage, creating a period of idle travel where the drive motor rotates but the load does not follow—that is, a return gap exists. The moment the gear surfaces re-contact during this return gap, an impact and torque spike occur, making it impossible to establish a continuous torque-angle correspondence, leading to momentary errors in the calculation. Additionally, in downhill conditions, when support arm 2 rotates along the direction of gravity, causing the motor to be in a reverse driving state, the force direction inside the transmission mechanism is completely reversed. At this point, the torque-current relationship is no longer monotonic and linear but rather complex and nonlinear—this is the nonlinear reverse-drive characteristic in downhill conditions. These mechanical characteristics can cause calculation errors in the unbalanced torque of the system.

[0058] It should be noted that the drive motor in this method can be either a first drive motor or a second drive motor. When it is a first drive motor, the support arm 2 is the first support arm 21 and the detection module 1 is the first detection module 11. When it is a second drive motor, the support arm 2 is the second support arm 22 and the detection module 1 is the second detection module 12.

[0059] The counterweight adjustment methods for support arm 2 include: S1: Control the drive motor to drive the support arm 2 to rotate in one direction at a constant speed for scanning.

[0060] In other words, the system's control module can control the drive motor to drive the support arm 2 to perform a forward (e.g., clockwise) uniform rotation scan at an extremely low speed ω0 within the maximum safe working angle range, or to perform a reverse (e.g., counterclockwise) uniform rotation scan at an extremely low speed ω0.

[0061] First, it should be noted that when the detection module 11 rotates at a constant angular velocity ω under the drive of the drive motor, according to rigid body dynamics and the principle of electromagnetic torque of the drive motor, the total electromagnetic torque T output by the drive motor is... motor The following dynamic equilibrium equations must be satisfied: Formula (1):

[0062] Among them, J For the inertial torque term, For unbalanced gravitational torque, For mechanical transmission friction torque, This is the total electromagnetic torque output by the drive motor.

[0063] Furthermore, when the support arm 2 performs a uniform rotational scan at an extremely low speed ω0, under the low-speed uniform scanning state (angular acceleration) ), thus the inertial torque term ( The torque output by the drive motor is zero; at this time, the torque output by the drive motor is only used to overcome the unbalanced gravitational torque and the mechanical transmission friction torque. The mechanical transmission friction torque always hinders the rotation of the support arm 2, and the unbalanced gravitational torque is only related to the rotation angle θ, that is, the rotation position of the support arm 2.

[0064] Therefore, during the forward and reverse uniform rotation scanning of the support arm 2, the torque output by the drive motor is: Formula (2):

[0065] During low-speed uniform scanning, the support arm 2 is always in a micro-motion state, with small fluctuations in friction force, which tends to be constant and easy to compensate for, thereby improving the accuracy and stability of angle measurement.

[0066] In practice, the support arm 2 can be rotated unidirectionally at a constant speed within the maximum safe working angle range (e.g., -10° to 130°). The maximum safe working angle range refers to the limit range of rotation that the support arm 2 is allowed to rotate in terms of its mechanical structure. Exceeding this range may result in mechanical damage or personnel safety risks.

[0067] When the drive motor switches from forward to reverse, that is, when the drive motor turns, the tooth surface in the transmission structure will cross the transmission gap from the side that is in contact with the tooth surface to contact the tooth surface on the other side, which will generate a backlash in both directions.

[0068] Therefore, by driving the support arm 2 to rotate and scan in one direction at a constant speed by the drive motor, the transmission gaps of all transmission mechanisms can be compressed to one side, which can eliminate the phase drift caused by the backlash in the forward and reverse directions from the root, thereby improving the calculation accuracy of unbalanced torque.

[0069] S2: Obtain the real-time drive current curve of the drive motor during unidirectional uniform rotation scanning.

[0070] If the rotation is in the forward direction, the system will automatically acquire the real-time forward drive current curve of the drive motor during the uniform rotation scan (such as clockwise); if the rotation is in the reverse direction, the system will automatically acquire the real-time reverse drive current curve of the drive motor during the uniform rotation scan (such as clockwise).

[0071] S3: Based on the real-time drive current curve, obtain the effective data range of the drive motor when it is under maximum load.

[0072] Understandably, during the entire unidirectional uniform speed scanning process, there will inevitably be an uphill peak where the drive motor overcomes the maximum gravitational torque, and a downhill trough where gravity drives the motor (this trough data is often distorted due to self-locking or gear backlash). When going uphill, gravity hinders rotation, forcing the drive motor to push forward, engaging in a positive contact motion. The transmission backlash is "locked" to one side, with no free travel.

[0073] Specifically, the effective data range of the drive motor under maximum load can be extracted from the real-time drive current curve. This range is near the data point where the drive motor overcomes the maximum gravitational torque, ensuring that the transmission gears maintain rigid contact on one side, the Coulomb friction force is constant in direction, and the transmission efficiency η is high. up By maintaining a stable linear constant, the complex downhill nonlinear region is perfectly avoided, thereby simplifying the data model and improving the accuracy of unbalanced torque calculation.

[0074] S4: Based on the data within the valid data range, fit and generate a partial cosine curve with DC bias.

[0075] Since the gravitational imbalance torque changes sinusoidally, the data within the effective data range can be fitted to generate a partial cosine curve with DC bias.

[0076] S5: Obtain the corresponding current amplitude and phase based on a partial cosine curve.

[0077] The corresponding current amplitude and phase are calculated from a portion of the cosine curve.

[0078] The current amplitude represents the characteristic value of the current amplitude under pure gravitational imbalance, and the phase is the characteristic value of the phase corresponding to the current amplitude.

[0079] S6: Based on the current amplitude and phase, obtain and adjust the connection position between the support arm 2 and the counterweight arm 3 and the installation position of the counterweight 4.

[0080] In other words, the mechanical adjustment amount that needs to be adjusted can be obtained based on the obtained current amplitude and phase. For example, the attitude angle θ can be adjusted by adjusting the connection position between the first adjustment hole 3111 and the first connecting rod 61, and the distance between the center of mass of the first counterweight 41 and the axis of rotation can be adjusted by adjusting the connection position between the second adjustment hole 312 and the first counterweight 41.

[0081] In the actual adjustment process, a coarse adjustment can be performed first, that is, the positions of the first adjustment hole 3111 and the second adjustment hole 312 have been initially determined. Then, a fine adjustment can be performed according to the counterweight adjustment method of the support arm 2. During the fine adjustment, the position of the first adjustment hole 3111 can be adjusted first, and then the position of the second adjustment hole 312 can be adjusted. If the position of the second adjustment hole 312 has been determined, the second connector 72 can be finely adjusted in the second connector hole 4111 to achieve a higher precision adjustment. The second connector hole 4111 can be set to extend radially so that the position of the second connector 72 can be moved radially outward or inward to achieve a higher precision adjustment.

[0082] Therefore, the above-mentioned counterweight adjustment method for support arm 2 can select the clearest and most linear area of ​​the physical model for mathematical calculation, without having to consider the complex issues of whether the transmission mechanism is self-locking in the downhill section of the system, thus simplifying the calculation process. The unidirectional rotation scanning ensures that the gaps of all transmission mechanisms are pressed to one side, eliminating the phase drift caused by the forward and reverse return gaps from the root, thereby overcoming the torque calculation errors caused by the asymmetry of forward and reverse friction, return gaps, and nonlinear reverse drive characteristics in the downhill state when using non-self-locking or weakly self-locking transmission mechanisms (such as worm gears and harmonic reducers), thus improving the accuracy of unbalanced torque calculation.

[0083] In some embodiments, obtaining the real-time drive current curve of the drive motor during unidirectional uniform rotation scanning includes: S21a: During the forward uniform rotation scanning process of the drive support arm 2, the forward real-time attitude angle and the corresponding forward real-time drive current fed back by the drive motor are obtained at a fixed frequency, and the forward real-time drive current curve is generated based on the forward real-time attitude angle and the forward real-time drive current.

[0084] S21b: Alternatively, during the reverse uniform rotation scanning process of the drive support arm 2, the reverse real-time attitude angle and the corresponding reverse real-time drive current fed back by the drive motor are obtained at a fixed frequency, and the reverse real-time drive current curve is generated based on the reverse real-time attitude angle and the forward real-time drive current.

[0085] Therefore, the real-time attitude angle is fed back through the driver of the drive motor. Corresponding real-time drive current Automatically generate real-time drive current curve I cw (θ).

[0086] In some embodiments, the effective data range for obtaining the drive motor when it is under maximum load and continuously outputting high power, based on the real-time drive current curve, includes: S31: Perform moving average filtering on the real-time drive current curve to obtain the maximum current point and the angle corresponding to the maximum current point.

[0087] Because the unbalanced torque of gravity changes sinusoidally, during the entire process of unidirectional uniform speed scanning, there will inevitably be an uphill peak where the driving motor overcomes the maximum gravitational torque, and a downhill trough where gravity drives the motor (the data of this trough is often distorted due to self-locking or gear backlash).

[0088] The system monitors the real-time drive current curve I. cw (θ) Performs moving average filtering to automatically find the point I with the maximum current. max and its corresponding angle θ max .

[0089] S32: Using the angle corresponding to the point of maximum current as the center, extract the effective data range on both sides.

[0090] The system uses the point of maximum current θ max Centered on the data, extract a valid data range to both sides, such as: [θ max θ1, θ max +θ1], where θ1 can be set to 40°, 45°, 50°, etc.

[0091] It should be noted that within this valid data range, the transmission gears of the transmission mechanism maintain a rigid contact on one side, the Coulomb friction is constant, and the transmission efficiency η upMaintaining a stable linear constant, it perfectly avoids the complex downslope nonlinear region. This is achieved by capturing the point θ where the current reaches its maximum value. max The effective data range in the vicinity is selected only for mathematical calculations in the area where the physical model is clearest and most linear. There is no need to consider the complex issue of whether the system is self-locking when it goes downhill, which simplifies the calculation process.

[0092] In some embodiments, fitting and generating a partial cosine curve with DC bias based on data within the valid data range includes: S41: Based on the first calculation formula, fit the data within the effective data range to generate a partial cosine curve with DC bias. The first calculation formula is: , For equivalent constant triboelectric current, For the equivalent current amplitude of the unbalanced gravitational torque, θ max For phase, It is a partial cosine curve.

[0093] It is important to note that: First, the aforementioned "extracting effective data ranges on both sides of the angle corresponding to the maximum current point (i.e., the maximum gravitational torque point)" is a preferred solution. However, the scanning range of the X-ray diffractometer 100 is limited (usually not 360°). If the initial phase of the centroid is not balanced, causing the maximum gravitational torque to appear outside the physical limit, then the real-time driving current curve acquired within the preset range will be a monotonically rising or falling curve, with no peaks at all. Forcibly searching for I in this case will be ineffective. max Extracting ±θ1 will result in an error or data truncation error. Therefore, as long as the scanning range is large enough (e.g., greater than 60°), even if only a portion of the sine curve is captured (without peaks / troughs), the amplitude and phase of the fundamental frequency can still be calculated by directly using the constrained least squares method to perform sine fitting on the entire effective data segment.

[0094] Secondly, when the system is in a state of slight imbalance (close to balance), the sinusoidal current fluctuation caused by gravity is extremely small. At this time, the fluctuation of the drive motor current will be completely dominated by noise from the gear reduction mechanism's cogging torque, high-frequency noise from gear meshing, and low-speed Stribeck friction ("low-speed Stribeck friction" refers to the special frictional resistance that exhibits high nonlinearity and decreases sharply with a slight increase in speed under extremely low-speed conditions due to the lubrication state being in the boundary region). If the system were to forcibly extract I at this time... max This can cause noise to be mistaken for gravity characteristics, leading to incorrect adjustment guidance and preventing the system from converging. Therefore, when the AC component (variance or fundamental frequency amplitude) of the acquired real-time drive current curve is less than the calibrated threshold ε, it should be directly determined that "equilibrium has been reached".

[0095] In some embodiments, obtaining the corresponding current amplitude and phase based on a partial cosine curve includes: The data within the valid data range is used to extract the fundamental frequency feature components using constrained least squares or machine learning / Fourier transform, and the current amplitude and phase are extracted based on the first calculation formula. The fitting algorithm automatically removes the constant term I. dc_fric This means achieving decoupling from friction, thereby directly extracting the amplitude characteristic value A and phase characteristic value θ representing the imbalance of pure gravity. max .

[0096] In some embodiments, adjusting the connection position between the support arm 2 and the counterweight arm 3 and the installation position of the counterweight 4 according to the current amplitude and phase includes: S61: Based on the calibrated system comprehensive mapping coefficients, the current amplitude and phase are mapped to the first mechanical adjustment amount and the second mechanical adjustment amount.

[0097] In other words, based on the calibrated system comprehensive mapping coefficients, the system can automatically convert the current amplitude A and phase θ. max The adjustment is mapped to a specific first mechanical adjustment amount and a second mechanical adjustment amount, and intuitive adjustment instructions are output to the operator on the display screen, so that the operator can mechanically adjust the installation position of the counterweight 4 on the counterweight arm 3 and the connection position between the support arm 2 and the detection module 11 according to the first mechanical adjustment amount and the second mechanical adjustment amount.

[0098] S62a: The support arm 2 and the counterweight arm 3 are detachably connected by holes corresponding to the first mechanical adjustment amount.

[0099] Specifically, the first mechanical adjustment corresponds to angle adjustment, i.e., adjustment. The angle between the straight line containing the counterweight arm 3, the counterweight 4 and the axis of rotation and the lever arm of the support arm 2 can be adjusted by the first adjustment hole 3111. In other words, the support arm 2 and the counterweight arm 3 can be detachably connected by the first adjustment hole 3111 corresponding to the first mechanical adjustment amount.

[0100] S62b: And, the counterweight 4 and the counterweight arm 3 are detachably connected by holes corresponding to the second mechanical adjustment amount.

[0101] Specifically, the second mechanical adjustment corresponds to the adjustment of the center of gravity position of the counterweight 4, i.e., adjustment. The distance between the center of mass of the counterweight 4 and the axis of rotation can be adjusted by the second adjustment hole 312. In other words, the counterweight arm 3 and the counterweight 4 can be detachably connected by the second adjustment hole 312 corresponding to the second mechanical adjustment amount.

[0102] In some embodiments, the system synthesis mapping coefficients are obtained using the vector incremental calibration method, which includes: S01. Record the initial vector: Record the first characteristic vector in the current unbalanced state. ; S02, Hanging a known weight: At the known lever arm position of support arm 2, hang a weight with a mass of m. sd Standard test weights; S03, Repeated unidirectional feature extraction: Execute steps between obtaining the connection position between the support arm 2 and the counterweight arm 3 and the installation position of the counterweight 4 based on the current amplitude and phase, i.e., execute steps S1 to S5, to obtain the second feature vector after the standard test weight is mounted. ; S04, Calculate the overall uphill gain of the system (K) uphill The first and second eigenvectors are subjected to vector difference operations in polar coordinates based on the second calculation formula, and the system comprehensive mapping coefficient K is obtained based on the third calculation formula. uphill ; The second calculation formula is as follows: The third calculation formula is: ΔA is A1-A0, g is the acceleration due to gravity, and m sd For the mass of the standard test weight, r std Given the position of the lever arm, K uphill These are the system synthesis mapping coefficients. The difference vector Δ The amplitude ΔA is purely caused by the standard test weights.

[0103] Therefore, the uphill efficiency η, which integrates the drive motor torque constant, transmission ratio, and other parameters that are difficult to measure separately, is obtained through the vector incremental calibration method. up System comprehensive mapping coefficient K uphill That is, the unknown frictional force I dc and unknown efficiency η up All of them are packaged into a comprehensive coefficient K. uphill In this process, there is no need to separately calculate the complex motor torque constant and mechanical efficiency, which facilitates mapping the current amplitude A into a mechanical adjustment quantity; and considering the nonlinear characteristics of the transmission mechanism's frictional force changing with the load, the negative unknown frictional force I can be determined through system-level calibration using standard test weights. dc and unknown efficiency η up All of them are packaged into a comprehensive coefficient K. uphill In the above, the fundamental frequency component of the relevant frictional force is equivalently converted to the comprehensive upslope gain coefficient K. uphill The calculations are simplified, making the overall method easier to implement.

[0104] In some embodiments, mapping the current amplitude and phase to a first mechanical adjustment and a second mechanical adjustment based on calibrated system synthesis mapping coefficients includes: S611a: Get the current imbalance vector. , This represents the current amplitude. This represents the current phase.

[0105] It should be noted that in practical applications, the unbalanced gravitational torque changes after each optical component replacement, meaning that the torque needs to be rebalanced after each replacement. After replacing the optical component, the system only needs to execute steps S1 to S5 once to obtain the current unbalanced vector. , The current amplitude is currently obtained. This represents the current phase.

[0106] S612a: Based on the current unbalance vector, the true unbalance torque is obtained using the fourth calculation formula, where the fourth calculation formula is: M unb For a real unbalanced torque, K uphill These are the system comprehensive mapping coefficients.

[0107] Therefore, based on the current unbalance vector, the true unbalance torque can be calculated, thereby achieving high-precision torque balance.

[0108] S613a: Based on the actual unbalanced torque, output the radial movement distance of the counterweight 4.

[0109] Therefore, the installation distance that the counterweight 4 needs to move on the counterweight arm 3 when it is in the current position of the second adjustment hole 312 can be obtained. For example, the system can output to the user how much radial movement distance (in millimeters) the counterweight 4 needs to move on the second adjustment hole 312.

[0110] In some embodiments, based on the actual unbalanced torque, the radial movement distance of the output counterweight 4 includes: S6131a: Outputs the radial movement distance of counterweight 4 based on the fifth calculation formula. The fifth calculation formula is: m block Let g be the mass of counterweight 4, g be the acceleration due to gravity, and ΔL be the radial distance that counterweight 4 moves.

[0111] Therefore, based on the actual unbalanced torque, the radial movement distance of the counterweight 4 is calculated, and the radial adjustment amount of the counterweight 4 corresponding to the actual unbalanced torque is obtained, which can ensure the adjustment accuracy.

[0112] In some embodiments, mapping the current amplitude and phase to a first mechanical adjustment and a second mechanical adjustment based on calibrated system synthesis mapping coefficients includes: S611b: Get the current imbalance vector. , This represents the current amplitude. This represents the current phase.

[0113] It should be noted that in practical applications, the unbalanced gravitational torque changes after each optical component replacement, meaning that the torque needs to be rebalanced after each replacement. After replacing the optical component, the system only needs to execute steps S1 to S5 once to obtain the current unbalanced vector. , The current amplitude is currently obtained. This represents the current phase.

[0114] S612b: Outputs the rotation angle of counterweight arm 3 based on the current unbalance vector.

[0115] Therefore, the direction of the unbalanced center of mass is θ. curr The system can calculate the angle that the counterweight arm 3 needs to rotate when it is in the current position of the first adjustment hole 3111. For example, the system can directly calculate and prompt the user to rotate the counterweight arm 3 (first adjustment hole 3111) to the opposite direction θ. curr The closest hole position is ±180°.

[0116] In some embodiments, the first mechanical adjustment amount is the connection angle between the support arm 2 and the counterweight arm 3, and the first mechanical adjustment command is configured to adjust the connection angle according to the phase to adjust the gravity arm angle of the counterweight 4 to compensate for the phase deviation of the unbalanced gravity torque generated during the rotation of the detection module 1.

[0117] Specifically, the current phase corresponds to the offset angle of the center of gravity of the counterweight 4 relative to the axis of rotation. Adjusting the connection angle between the support arm 2 and the counterweight arm 3 according to the current phase offset can directly change the position of the center of gravity of the counterweight 4 relative to the axis of rotation, which means changing the lever arm angle of the gravity acting on the counterweight 4, i.e., the gravity lever arm angle. This allows the reverse torque generated by the counterweight 4 and the unbalanced gravity torque generated during the rotation of the detection module 1 to maintain phase matching, thereby offsetting the phase deviation of the unbalanced gravity torque generated during the rotation of the detection module 1, achieving torque balancing and improving detection accuracy.

[0118] The second mechanical adjustment amount is the radial distance between the counterweight 4 and the counterweight arm 3. The second mechanical adjustment command is configured to adjust the radial distance according to the current amplitude to adjust the length of the gravity arm of the counterweight 4 to compensate for the amplitude deviation of the unbalanced gravity torque generated during the rotation of the detection module 1.

[0119] Specifically, the current current amplitude corresponds to the radial distance of the counterweight 4 on the counterweight arm 3. The radial distance is the distance between the center of mass of the counterweight 4 and the axis of rotation. By adjusting the radial distance of the counterweight 4 on the counterweight arm 3 according to the current current amplitude, the length of the gravity arm (d2) of the counterweight 4 can be directly changed. This allows the reverse torque generated by the counterweight 4 and the unbalanced gravity torque generated during the rotation of the detection module 1 to maintain amplitude matching, thereby offsetting the amplitude deviation of the unbalanced gravity torque generated during the rotation of the detection module 1, achieving torque balancing and improving detection accuracy.

[0120] Therefore, by adjusting the counterweight 4 with the first and second mechanical adjustment amounts, the unbalanced gravitational torque generated during the rotation of the detection module 1 can be effectively counteracted, thus achieving effective balance of the unbalanced gravitational torque.

[0121] For example, if the amplitude of the unbalanced gravitational moment is too large, the radial spacing can be increased, that is, the counterweight 4 can be adjusted radially outward to increase the length of the gravity lever arm of the counterweight 4 and increase the reverse torque to match the amplitude of the unbalanced gravitational moment generated during the rotation of the detection module 1; if the amplitude of the unbalanced gravitational moment is too small, the radial spacing can be decreased, that is, the counterweight 4 can be adjusted radially inward to decrease the length of the gravity lever arm of the counterweight 4 and decrease the reverse torque to match the amplitude of the unbalanced gravitational moment generated during the rotation of the detection module 1. Furthermore, if the phase of the unbalanced gravitational moment is ahead, the connection angle can be increased to match the phase of the unbalanced gravitational moment generated during the rotation of the detection module 1; if the phase of the unbalanced gravitational moment is behind, the connection angle can be decreased to match the phase of the unbalanced gravitational moment generated during the rotation of the detection module 1.

[0122] In some embodiments, the center of mass of the counterweight 4, the center of mass of the counterweight arm 3, and the axis of rotation of the support arm 2 are collinear.

[0123] The pivot of the support arm 2 is the rotation axis 5. The support arm 2 rotates around the rotation axis 5. That is, the center of mass of the counterweight 4, the center of mass of the counterweight arm 3 and the axis of rotation 5 are collinear. As a result, the entire counterweight system will not generate additional torque. It only retains the effective counterweight torque to offset the unbalanced gravity torque of the detection module 1, and will not introduce additional errors. It can ensure effective torque balancing.

[0124] Furthermore, the holes corresponding to the first mechanical adjustment amount are arranged in a circle around the axis of rotation of the support arm 2, and the holes corresponding to the second mechanical adjustment amount are arranged in a direction parallel to the line connecting the center of mass of the counterweight 4 and the axis of rotation of the support arm 2.

[0125] Reference Appendix Figure 4As shown, the hole corresponding to the first mechanical adjustment amount is the first adjustment hole 3111, and the hole corresponding to the second mechanical adjustment amount is the second adjustment hole 312. Multiple first adjustment holes 3111 are arranged circumferentially around the axis of rotation of the support arm 2 (the axis of rotation of the shaft 5), and multiple second adjustment holes 312 are arranged along a line parallel to the line connecting the center of mass of the counterweight 4 and the axis of rotation of the support arm 2 (the axis of rotation of the shaft 5). Therefore, by connecting the support arm 2 to the first adjustment holes 3111 at different positions, the angle of the gravity arm of the counterweight 4 can be adjusted. The counterweight 4 can be adjusted by connecting it to the second adjustment holes 312 at different positions, thereby adjusting the length (d2) of the gravity arm of the counterweight 4. In other words, the angle of the gravity arm of the counterweight 4 can be adjusted independently through the first adjustment hole 3111. The length of the gravity arm (d2) of the counterweight 4 can be adjusted independently through the second adjustment hole 312, thereby decoupling the adjustment of the length of the gravity arm (d2) and the adjustment of the length of the gravity arm (d2), so that the angle adjustment and radial position adjustment of the counterweight 4 do not affect each other, and the adjustment convenience is improved.

[0126] The present invention also proposes a counterweight adjustment system for the support arm 2 of an X-ray diffractometer 100.

[0127] The counterweight adjustment system for the support arm 2 of the X-ray diffractometer 100 according to the embodiments of the present invention is applicable to the counterweight adjustment method for the support arm 2 of the X-ray diffractometer 100 in any of the above embodiments.

[0128] First, it should be noted that there is a common design inertia and cognitive misconception: that small or even partially significant imbalances in gravitational torque will not have a substantial impact on the final angular accuracy, thus the further improvement of counterweight accuracy is generally ignored in system design.

[0129] The fundamental reason for this perception lies in the fact that the angle accuracy of high-end goniometers now heavily relies on the following three core technologies for "forced compensation": First, it relies on fully closed-loop control and a high-precision absolute value circular grating (axis-end feedback). Modern high-end goniometers no longer rely on the number of rotation steps of the drive motor or the transmission ratio of the reduction mechanism for angle readings. Instead, they directly mount an extremely high-resolution optical circular grating on the main shaft (the final rotation axis). Under the fully closed-loop control architecture, the circular grating only reads the absolute true angle of rotation of the main shaft. Regardless of the amount of backlash (playback) in the front-end drive chain, and regardless of which side the support arm's gravitational torque is biased towards, as long as the grating reading has not reached the target position, the drive motor will continuously output torque for compensation. Therefore, minor imbalances in gravitational torque are often "forced smoothed out" by the control system and the closed-loop algorithm of the grating, and are not macroscopically reflected as static angle errors. Second, it relies on the high rigidity of the transmission mechanism. Modern goniometers widely employ high-rigidity transmission schemes such as dual-lead worm gears or direct-drive motors (DD motors) combined with harmonic reducers. These high-rigidity transmission mechanisms ensure that the system remains completely unaffected by minor off-center loads caused by changes in force, even when subjected to changes in force such as the replacement of optical accessories weighing hundreds or even thousands of grams. Thirdly, they rely on the high bending section modulus (extremely low deflection) of structural components. The support arms of high-end instruments are typically made of high-strength cast iron or aluminum alloy and possess extremely high bending section thickness; tens of N... The elastic deformation (deflection) caused by the torque imbalance of m acting on the high-rigidity support arm is only on the order of micrometers. The angular deformation converted to the angular radius is usually less than 1 arcsecond, which is far below the nominal accuracy tolerance range of the X-ray diffractometer system.

[0130] Therefore, existing X-ray diffractometers often use fixed counterweights or only provide a few sets of rough stepped mounting holes. It has not been found that insufficient precision of the support arm counterweight will have an adverse effect on the X-ray diffractometer (especially high-precision X-ray diffractometers).

[0131] However, this application finds that insufficient counterweight accuracy of the support arm will have at least the following adverse effects on the X-ray diffractometer: 1. If the gravitational torque is unbalanced, the drive motor must continuously output a very large holding current to counteract gravity while maintaining the support arm at a certain angle; the large current will cause the drive motor to overheat severely, and the heat will be conducted to the goniometer spindle and grating through the flange. Thermal expansion and contraction will cause changes in mechanical dimensions at the microscopic level (thermal drift); the slow scan of a sample by the X-ray diffractometer may take several hours, and thermal drift will have a significant impact on the entire spectrum. 2. In continuous scanning mode, if the gravitational torque is unbalanced, the load on the drive motor will fluctuate when going uphill (overcoming gravity) and downhill (adapting to gravity), which will cause small pulsations in the drive motor speed; this speed pulsation will cause high-frequency micro-vibrations in the whole machine, causing micron-level tremors in the X-ray spot on the sample surface, reducing the signal-to-noise ratio of the detector signal. 3. If the laboratory suddenly loses power during high-angle testing, and the transmission system lacks absolute self-locking capability (such as some direct-drive solutions), the top-heavy support arm will fall freely under gravity, easily damaging expensive detectors or X-ray tubes. 4. Long-term unbalanced operation will lead to accelerated wear on one side of the worm gear or bearings, causing a gradual decrease in equipment accuracy.

[0132] In practical applications, to adapt to different testing needs such as powders, thin films, and trace samples, it is necessary to frequently plug in and replace various optical components (such as Solar slits at different angles, Kβ filters, diverging slits, anti-scattering attenuators, etc.) at the incident or receiving end. This frequent replacement of optical components inevitably leads to high-frequency and dynamic changes in the overall mass and center of mass of the support arm. Although existing closed-loop control and high-rigidity mechanical systems can "forcefully" stabilize static angle readings, this design philosophy of "not pursuing precise torque balance, but relying on the drive motor and mechanical structure to resist" exposes extremely serious deep-seated problems under dynamic low-speed operation conditions such as continuous scanning and long-term continuous operation: it severely exacerbates the lag error of the servo control system and the torsional elastic deformation of the transmission chain, causing microscopic speed pulsations when the angle measuring spindle crosses the equivalent zero point of gravity, reducing the smoothness of low-frequency scanning and the signal-to-noise ratio of the diffraction pattern; it forces the drive motor to continuously output a large static holding current during long-term extremely low-speed scanning, causing severe overheating of the drive motor, which in turn causes thermal drift of the goniometer spindle and grating system, seriously damaging the thermal stability of the instrument during long-term operation.

[0133] In this application, a counterweight arm 3, which rotates coaxially and has an adjustable connection position, is connected to the support arm 2. A counterweight component 4, also with an adjustable position, is installed on the counterweight arm 3, making precise adjustment easy and improving adjustment accuracy. This, in turn, helps improve torque balance accuracy. Furthermore, the counterweight adjustment method of the support arm 2 allows for absolute accuracy in torque balancing, further enhancing torque balance accuracy. In other words, the counterweight adjustment system of the support arm 2 of the X-ray diffractometer 100 of this application can effectively solve the problem of minute gravitational torque imbalance caused by high-frequency insertion and removal of optical components, thereby eliminating dynamic scanning disturbance sources and heat sources at their root.

[0134] Therefore, the counterweight adjustment system of the support arm 2 of the X-ray diffractometer 100 of this application can effectively reduce the static holding current of the drive motor and the heat source input of the goniometer by improving the accuracy of the gravitational torque balance, thereby improving the long-term stability of the X-ray diffractometer 100; it can make the drive motor operate under the same load as much as possible throughout the scanning cycle, reducing the sudden load changes of the drive motor, thereby making the operation of the support arm 2 smoother, reducing low-frequency resonance, and improving the signal-to-noise ratio of diffraction data; through precise centroid coincidence counterweight, it is beneficial for the system to achieve power failure suspension, thereby reducing the risk of instrument collision damage caused by power failure; and reasonable counterweight can make the bearings and tooth surfaces bear force evenly, reducing the wear of worm gears or bearings, which is conducive to improving the accuracy of the equipment under long-term use.

[0135] According to the embodiment of the present invention, the counterweight adjustment system of the support arm 2 of the X-ray diffractometer 100 can improve the calculation accuracy of unbalanced torque, improve the torque balancing accuracy, and achieve the balance of gravitational torque by applying the above-described counterweight adjustment method of the support arm 2 of the X-ray diffractometer 100. This can improve the overall performance of the X-ray diffractometer 100 and effectively improve the detection accuracy.

[0136] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0137] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for adjusting the counterweight of the support arm of an X-ray diffractometer, characterized in that, The X-ray diffractometer includes a detection module (1) and a drive motor. The detection module (1) is mounted on a support arm (2). The drive motor is used to drive the support arm (2) to rotate so as to drive the detection module (1) to rotate. The support arm (2) is connected to a counterweight arm (3) that rotates along a coaxial axis and whose connection position is adjustable. The counterweight arm (3) is equipped with a counterweight component (4) whose position is adjustable. The counterweight adjustment method of the support arm includes: The drive motor is controlled to drive the support arm (2) to rotate in one direction at a constant speed for scanning; Obtain the real-time drive current curve of the drive motor during unidirectional uniform rotation scanning; Based on the real-time drive current curve, obtain the effective data range of the drive motor at its maximum load state; Based on the data within the effective data range, a partial cosine curve with DC bias is fitted and generated. Based on the aforementioned partial cosine curve, the corresponding current amplitude and phase are obtained; The connection position of the support arm (2) and the counterweight arm (3) and the installation position of the counterweight (4) are adjusted according to the current amplitude and the phase.

2. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 1, characterized in that, The acquisition of the real-time drive current curve of the drive motor during unidirectional uniform speed rotation scanning includes: During the forward uniform speed rotation scanning process of the support arm (2), the forward real-time attitude angle and the corresponding forward real-time drive current fed back by the drive motor are obtained at a fixed frequency, and a forward real-time drive current curve is generated based on the forward real-time attitude angle and the forward real-time drive current. Alternatively, during the reverse uniform rotation scanning process of the support arm (2), the reverse real-time attitude angle and the corresponding reverse real-time drive current fed back by the drive motor are obtained at a fixed frequency, and a reverse real-time drive current curve is generated based on the reverse real-time attitude angle and the reverse real-time drive current.

3. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 2, characterized in that, The step of obtaining the effective data range for the drive motor at its maximum load state based on the real-time drive current curve includes: The real-time drive current curve is filtered by moving average to obtain the maximum current point and the angle corresponding to the maximum current point. Using the angle corresponding to the maximum current point as the center, extract the effective data range to both sides.

4. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 1, characterized in that, The step of fitting and generating a partial cosine curve with DC bias based on the data within the effective data range includes: Based on the first calculation formula, the data within the effective data range are fitted to generate a partial cosine curve with DC bias. The first calculation formula is: , For equivalent constant triboelectric current, For the equivalent current amplitude of the unbalanced gravitational torque, θ max For phase, It is a partial cosine curve.

5. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 4, characterized in that, The step of obtaining the corresponding current amplitude and phase based on the partial cosine curve includes: The data within the effective data range are used to extract the fundamental frequency feature components using constrained least squares or machine learning / Fourier transform, and the current amplitude and phase are extracted based on the first calculation formula.

6. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 1, characterized in that, The adjustment of the connection position between the support arm (2) and the counterweight arm (3) and the installation position of the counterweight (4) based on the current amplitude and the phase includes: Based on the calibrated system comprehensive mapping coefficients, the current amplitude and the phase are mapped to a first mechanical adjustment amount and a second mechanical adjustment amount; The support arm (2) and the counterweight arm (3) are detachably connected by holes corresponding to the first mechanical adjustment amount; In addition, the counterweight (4) and the counterweight arm (3) are detachably connected by holes corresponding to the second mechanical adjustment amount.

7. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 6, characterized in that, The system's comprehensive mapping coefficients are obtained through a vector incremental calibration method, which includes: Record the first eigenvector in the current unbalanced state. ; At the known lever arm position of the support arm (2), a mass of m is mounted. sd Standard test weights; The steps of adjusting the connection position between the support arm (2) and the counterweight arm (3) and the installation position of the counterweight (4) based on the current amplitude and the phase are performed to obtain the second characteristic vector after the standard test weight is mounted. ; The first feature vector and the second feature vector are subjected to vector difference operation in polar coordinates based on the second calculation formula, and the system comprehensive mapping coefficient K is obtained based on the third calculation formula. uphill ; The second calculation formula is as follows: The third calculation formula is: ΔA is A1-A0, g is the acceleration due to gravity, and m sd For the mass of the standard test weight, r std Given the position of the lever arm, K uphill These are the system comprehensive mapping coefficients.

8. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 6, characterized in that, The step of mapping the current amplitude and the phase to a first mechanical adjustment amount and a second mechanical adjustment amount according to the calibrated system comprehensive mapping coefficient includes: Obtain the current imbalance vector, the , The amplitude of the current is currently stated. The phase currently described; Based on the current unbalance vector, the true unbalance torque is obtained using the fourth calculation formula, which is: M unb For a real unbalanced torque, K uphill These are the system comprehensive mapping coefficients; Based on the actual unbalanced torque, the radial movement distance of the counterweight (4) is output.

9. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 8, characterized in that, The calculation of the radial movement distance of the counterweight (4) based on the actual unbalanced torque includes: The radial movement distance of the counterweight (4) is output based on the fifth calculation formula, which is: m block Let g be the mass of the counterweight (4), g be the gravitational acceleration, and ΔL be the radial distance the counterweight (4) moves.

10. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 6, characterized in that, The step of mapping the current amplitude and the phase to a first mechanical adjustment amount and a second mechanical adjustment amount according to the calibrated system comprehensive mapping coefficient includes: Obtain the current imbalance vector, the , The amplitude of the current is currently stated. The phase currently described; The rotation angle of the counterweight arm (3) is output based on the current unbalance vector.

11. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 6, characterized in that, The first mechanical adjustment amount is the connection angle between the support arm (2) and the counterweight arm (3). The first mechanical adjustment command is configured to adjust the connection angle according to the phase to adjust the gravity lever arm angle of the counterweight (4) to compensate for the phase deviation of the unbalanced gravity torque generated during the rotation of the detection module (1). The second mechanical adjustment amount is the radial distance of the counterweight (4) on the counterweight arm (3). The second mechanical adjustment command is configured to adjust the radial distance according to the current amplitude to adjust the length of the gravity arm of the counterweight (4) to compensate for the amplitude deviation of the unbalanced gravity torque generated during the rotation of the detection module (1).

12. The method for adjusting the counterweight of the support arm of an X-ray diffractometer according to claim 11, characterized in that, The center of mass of the counterweight (4), the center of mass of the counterweight arm (3), and the axis of rotation of the support arm (2) are collinear; The holes corresponding to the first mechanical adjustment amount are arranged in a circle around the axis of rotation of the support arm (2), and the hole arrangement direction corresponding to the second mechanical adjustment amount is parallel to the line connecting the center of mass of the counterweight (4) and the axis of rotation of the support arm (2).

13. A counterweight adjustment system for the support arm of an X-ray diffractometer, characterized in that, A method for adjusting the counterweight of the support arm of an X-ray diffractometer applicable to any one of claims 1-12.

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