Displacement sensor, galvanometer motor system, assembly method and signal processing method

Abstract

The present invention discloses a displacement sensor, a galvanometer motor system, an assembly method, and a signal processing method. The displacement sensor is connected to the motor shaft and employs a transmissive grating sandwich structure. The transmissive grating sandwich structure comprises: a light source module, disposed on an upper layer, containing an aspheric collimating lens capable of generating a uniform parallel light beam; a grating code disk, disposed on a middle layer and made of an optical glass substrate, secured to the motor shaft via a code disk tray; and a photoelectric receiving module, disposed on a lower layer. The photoelectric receiving module comprises multiple groups of orthogonally arranged photodiodes and a photoelectric converter. The photodiodes receive light and dark variations in light fringes and generate optical signals, and the photoelectric converter receives the optical signals and converts them into electrical signals. The present invention reduces the size of the structure, improves position subdivision accuracy, enhances signal processing speed, and improves anti-interference capabilities, thereby enhancing the performance of the galvanometer motor system.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a displacement sensor, a galvanometer motor system, an assembly method and a signal processing method. Background Art

[0002] A galvanometer motor system is a precision oscillating actuator based on electromagnetic drive. It achieves nanometer-scale positioning of the laser beam through high-speed, periodic deflection of the lens. It is widely used in laser precision processing (such as wafer cutting and 3D printing), optical inspection (such as surface profile scanning), and biomedical imaging. The core function of the galvanometer motor system is dynamic angle-spatial position decoupling control, requiring microsecond-level response to replicate the preset trajectory to the actual lens deflection angle. In this process, the position feedback system, as a key link in closed-loop control, plays the following core roles:

[0003] (1) Real-time deviation correction: During high-speed scanning, the instantaneous deviation of the galvanometer rotor caused by the inertia moment and external load disturbance needs to be compensated through the position data closed loop;

[0004] (2) Jitter suppression: The resolution and delay of position feedback are directly related to the positioning jitter of the laser focus, such as the line width error in semiconductor cutting ≯0.1 μm;

[0005] (3) Constraints on system bandwidth: The upper limit of the closed-loop bandwidth is determined by the total delay of the feedback link (sensing + processing + transmission). The mechanical resonance frequency of the galvanometer motor system is often 5-20 kHz, but when the feedback delay is greater than 2 μs, the available bandwidth of the system is compressed to ≤2 kHz, resulting in a significant deterioration of the laser scanning rate and processing efficiency.

[0006] Currently, the commonly used high-precision displacement detection equipment on the market is mainly manufactured based on the principle of optical signal modulation and reception. Its core function is to convert mechanical rotation into electrical pulse signals through the on-off changes of light. Its working principle can be broken down into the following three core physical processes:

[0007] (1) Optical path modulation: The core component of the encoder is a transparent disc (code disc) with an equally spaced opaque grid engraved on its surface. The grid density determines the resolution (e.g., for a 100-line / turn code disc, each grid corresponds to a 3.6° rotation angle). A light source (usually an LED) emits parallel light from one side of the code disc; as the code disc rotates, the opaque grid periodically blocks the light beam, allowing the photodetector on the other side to receive alternating light and dark signals.

[0008] (2) Photoelectric conversion: The photodiode / transistor receives the light signal transmitted through the code disk and converts it into a current signal with varying strengths. Through signal conditioning and amplification, a voltage signal that can be collected is formed to complete the simulation of the displacement signal.

[0009] (3) Signal processing: Some products directly output analog signals as the only signal, while some products convert electrical signals into pulses or fixed-format digital signal encoding before outputting them.

[0010] The specific problems existing in the application of existing products in the galvanometer motor system are:

[0011] (1) Conflict between physical configuration and system integration: Industrial-grade high-precision grating encoders generally adopt a universal packaging structure (outer diameter > Φ25 mm), which seriously conflicts with the ultra-thin cavity space of the galvanometer motor (typical requirement ≤ Φ15 mm), resulting in physical interference.

[0012] (2) The electrical signal processing system is simple:

[0013] ① In the basic signal conditioning stage, the primary solution uses only a low-end operational amplifier to directly amplify the raw Sin / Cos signal (typical gain error ±5%) without filtering or shaping circuits. This results in a low signal-to-noise ratio and inability to perform fine segmentation. An improved solution adds an RC filter network (cutoff frequency ~10 kHz), but this fails to eliminate the differential noise spikes during the galvanometer acceleration phase and also results in phase lag.

[0014] ② Lack of signal shaping function. The uneven stripes produced during the grating engraving process, as well as the dust, oil and light source signal attenuation encountered during operation, will affect the accuracy of position segmentation. Therefore, traditional encoders cannot achieve high accuracy due to the lack of signal shaping function.

[0015] (3) Segmentation algorithm and accuracy bottleneck:

[0016] ① No subdivision / direct analog output. Some low-end solutions directly output the original analog signal (such as ±5 V differential), forcing the controller to perform all interpolation operations. This will cause a lot of interference to the signal before it is transmitted to the controller, ultimately resulting in a reduction in effective subdivision accuracy.

[0017] ② The simple digital subdivision capability is insufficient. For example, a fixed coefficient hardware subdivision device (such as 4×-16×) is used. However, due to volume limitations, the encoder usually cannot accommodate large-scale processing circuits. Therefore, a simple analog comparator circuit is used for subdivision. Due to the low subdivision, it cannot meet the high-precision working requirements of the galvanometer motor system. The single-grid pitch subdivision requirement of the galvanometer motor system is 8192 x (calculated based on a grating pitch of 40um, the position resolution after subdividing 8192 can reach 4.88nm).

[0018] (4) Inherent defects in signal transmission mode:

[0019] ① Analog transmission (such as ±1 V differential) has the disadvantages of weak resistance to common-mode interference and large signal attenuation rate during long-distance transmission;

[0020] ② Pulse counting transmission (such as A / B orthogonal pulse) relies on high-frequency carrier (typically 10 MHz) and is susceptible to electromagnetic interference (bit error rate > 10 -4 ) and is incompatible with absolute position feedback, requiring an additional initialization process;

[0021] ③ Low-speed digital buses (such as RS485, 2.5 Mbps) have uncontrollable transmission delays (single-frame data delay ≥ 4 μs), resulting in a 30% decrease in the galvanometer phase margin. Multi-axis collaboration requires polling communication, which exacerbates jitter (measured multi-axis synchronization error > 25 μrad).

[0022] In summary, existing solutions face the following irreconcilable conflicts in the galvanometer motor system:

[0023] (1) Physical adaptability: The standard encoder size is inconsistent with the geometry of the galvanometer cavity;

[0024] (2) Signal chain integrity: There are cascade errors in the entire chain from filtering and shaping, high-multiplication subdivision to high-speed transmission;

[0025] (3) Dynamic performance matching: The encoder delay and noise level result in the galvanometer control bandwidth being limited to <2kHz (much lower than the theoretical mechanical bandwidth ≥5kHz).

[0026] The fundamental reason for this contradiction is that the design concept of traditional encoders focuses on general servo scenarios. Therefore, how to overcome these contradictions and improve the performance of galvanometer motor systems is a problem that technicians in this field need to solve. Summary of the Invention

[0027] The embodiments of the present invention provide a displacement sensor, a galvanometer motor system, an assembly method, and a signal processing method, aiming to improve the use effect of the galvanometer motor system.

[0028] In a first aspect, an embodiment of the present invention provides a displacement sensor connected to a motor shaft, wherein the displacement sensor adopts a transmissive grating sandwich structure, and the transmissive grating sandwich structure includes:

[0029] A light source module is provided on the upper layer, wherein the light source module includes an aspheric collimating lens capable of generating a uniform parallel light beam;

[0030] The grating code disk is arranged in the middle layer. The grating code disk is made of an optical glass substrate and is fixed on the motor shaft through a code disk tray.

[0031] The photoelectric receiving module is arranged in the lower layer. The photoelectric receiving module includes multiple groups of orthogonally arranged photodiodes and photoelectric converters, and the photoelectric converters are fixed on the motor stator. The photodiodes are used to receive the brightness changes of the light stripes and form light signals. The photoelectric converters are used to receive the light signals and convert them into electrical signals.

[0032] In a second aspect, an embodiment of the present invention provides an assembly method of a displacement sensor, which is applied to the displacement sensor according to the first aspect. The assembly method includes:

[0033] Fixing the code disc tray on the motor shaft and placing the grating code disc on the disc surface of the code disc tray;

[0034] Controlling the motor shaft to rotate at a constant speed and detecting whether the rotation center of the grating code disk is concentric with the rotation center of the motor shaft;

[0035] When the rotation center of the grating code disk is not concentric with the rotation center of the motor shaft, monitoring the runout of the grating code disk from the edge of the grating code disk;

[0036] The grating code disk is corrected based on the jitter of the grating code disk so that the rotation center of the grating code disk is concentric with the rotation center of the motor shaft.

[0037] In a third aspect, an embodiment of the present invention provides a galvanometer motor system, comprising the displacement sensor as described in the first aspect.

[0038] In a fourth aspect, an embodiment of the present invention provides a signal processing method for a galvanometer motor system, which is applied to the galvanometer motor system as described in the third aspect, and the signal processing method includes:

[0039] Acquire an optical signal of a target object and convert the optical signal into a digital signal;

[0040] performing bias conditioning and amplitude conditioning on the digital signal to obtain a target signal;

[0041] Performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information;

[0042] The location information is packaged and output according to a set format.

[0043] Furthermore, acquiring the optical signal of the target object and converting the optical signal into a digital signal includes:

[0044] Converting the optical signal into an electrical signal using a photoelectric converter;

[0045] Amplifying the electrical signal through an analog amplification circuit to obtain an analog signal;

[0046] The analog information is converted into digital form to obtain the digital signal.

[0047] Furthermore, performing bias conditioning and amplitude conditioning on the digital signal to obtain a target signal includes:

[0048] Obtaining a voltage sine cycle of the digital signal;

[0049] Sampling the maximum voltage and the minimum voltage in the sinusoidal cycle;

[0050] According to the following formula, a bias voltage is calculated in combination with a set voltage, and the bias voltage is used to perform bias conditioning on the digital signal;

[0051] COMPEN = RAW-(TAR_CEN-((MAX-MIN) / 2+MIN));

[0052] Where COMPEN represents the bias-adjusted voltage, RAW represents the raw input voltage, TAR_CEN represents the set voltage, MAX represents the maximum voltage, MIN represents the minimum voltage, and TAR_CEN-((MAX-MIN) / 2+MIN) represents the bias voltage.

[0053] Furthermore, the step of performing bias adjustment and amplitude adjustment on the digital signal to obtain a target signal further includes:

[0054] According to the following formula, a gain ratio is calculated in combination with a preset standard signal peak-to-peak value, and the digital signal is amplitude conditioned according to the gain ratio;

[0055] OUT = ((MAX-MIN) / STAD)*RAW;

[0056] Where OUT is the amplitude-adjusted voltage, STAD is the peak-to-peak value of the standard signal, and (MAX - MIN) / STAD is the gain ratio.

[0057] Furthermore, performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information includes:

[0058] Obtaining a sinusoidal period of the target signal, and extracting a first sinusoidal signal and a second sinusoidal signal having a phase difference of 90° from the sinusoidal period of the target signal;

[0059] Performing polar coordinate conversion on the first sinusoidal signal and the second sinusoidal signal, and forming a Lissajous circle based on the fluctuation periods of the first sinusoidal signal and the second sinusoidal signal;

[0060] According to the following formula, for any point on the Lissajous circle, the corresponding angle information is calculated:

[0061] α=atan (Y / X) = atan (B / A);

[0062] Wherein, α represents angle information, atan represents the inverse tangent trigonometric function, A represents the first sine signal, B represents the second sine information, and X and Y represent the coordinates of any point on the Lissajous circle;

[0063] The position information is calculated by combining the angle information according to the following formula:

[0064] P = (N*M) + α / 360*N;

[0065] Where P represents the position information, N represents the subdivision ratio, and M represents the number of sine cycles.

[0066] Furthermore, the step of acquiring the optical signal of the target object and converting the optical signal into a digital signal further includes:

[0067] Comparing the optical signal with a preset first signal amplitude and a second signal amplitude, respectively; wherein the first signal amplitude is higher than the second signal amplitude;

[0068] When the optical signal exceeds the first signal amplitude, the base of the photoelectric receiver is step-cut to expand the gap between the grating code disk and the photoelectric converter;

[0069] When the optical signal is lower than the second signal amplitude, a spacer is inserted between the grating code disk and the photoelectric converter to reduce the gap between the grating code disk and the photoelectric converter.

[0070] Furthermore, after the step of performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information, the method further includes:

[0071] The position information is filtered.

[0072] Embodiments of the present invention provide a displacement sensor, a galvanometer motor system, an assembly method, and a signal processing method. By optimizing the design and employing advanced manufacturing processes, the embodiments of the present invention significantly reduce the overall size of the encoder, making it more compact and thus better adapted to the limited space of the galvanometer motor. Furthermore, by employing high-resolution sensors and sophisticated signal processing algorithms, the accuracy of position subdivision is significantly improved, ensuring high-precision positioning and motion control of the galvanometer motor. Furthermore, by improving signal transmission technology and enhancing electromagnetic compatibility design, the encoder's transmission speed is significantly increased, while also possessing stronger anti-interference capabilities, ensuring stable operation even in complex electromagnetic environments. This improves the overall performance of the galvanometer motor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0074] Figure 1 A schematic structural diagram of a displacement sensor provided by an embodiment of the present invention;

[0075] Figure 2 A schematic structural diagram of a displacement sensor provided by an embodiment of the present invention from another perspective;

[0076] Figure 3 A schematic flow chart of an assembly method of a displacement sensor provided by an embodiment of the present invention;

[0077] Figure 4 A schematic flow chart of a signal processing method for a galvanometer motor system provided in an embodiment of the present invention;

[0078] Figure 5 A first exemplary diagram of a signal processing method for a galvanometer motor system provided by an embodiment of the present invention;

[0079] Figure 6 A second exemplary diagram of a signal processing method for a galvanometer motor system provided by an embodiment of the present invention;

[0080] Figure 7 This is a third example diagram of a signal processing method for a galvanometer motor system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0081] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0082] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0083] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used in the specification and appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0084] It should be further understood that the term "and / or" used in the present description and appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0085] See below Figure 1 and Figure 2 The embodiment of the present invention provides a displacement sensor connected to the motor shaft 1. The displacement sensor adopts a transmission grating sandwich structure. The transmission grating sandwich structure includes:

[0086] A light source module 2 is provided on the upper layer, and the light source module 2 includes an aspheric collimating lens capable of generating a uniform parallel light beam;

[0087] The grating code disk 3 is arranged in the middle layer. The grating code disk 3 is made of an optical glass substrate and is fixed to the motor shaft 1 through a code disk tray 4;

[0088] The photoelectric receiving module 5 is arranged in the lower layer. The photoelectric receiving module 5 includes multiple groups of orthogonally arranged photodiodes and photoelectric converters, and the photoelectric converter is fixed on the motor stator 6. The photodiode is used to receive the brightness changes of the light stripes and form an optical signal. The photoelectric converter is used to receive the optical signal and convert it into an electrical signal.

[0089] In this embodiment, the displacement sensor structure adopts a transmissive grating sandwich structure, which is divided into three layers:

[0090] The upper light source module 2 uses a high-power LED and an aspheric collimating lens to generate a uniform parallel beam, with a spot uniformity exceeding 95%;

[0091] The middle layer of the grating code disk 3 is made of an ultra-thin optical glass substrate, and can also be made of other light-transmitting materials. Furthermore, the surface of the code disk is plated with a hard anti-reflection coating, including but not limited to anti-reflection coatings, anti-reflection coatings, polarization coatings, and coatings that can limit wavelength bandwidth. The grating design includes but is not limited to incremental code channels, such as Figure 2The grating track 9 is divided into 1024 equally spaced lines, and is inscribed with uniformly periodic grating stripes. The period is 20µm or 40µm, but not limited to these two. The track also includes marking lines for determining the absolute position of the grating disk. When light passes through the markings, it forms alternating light and dark stripes.

[0092] The photoelectric receiving module 5 on the lower layer includes four groups of orthogonally arranged photodiodes, which are used to receive the brightness changes of the light stripes and convert them into electrical signals, which are finally output in the form of differential signals. The photoelectric converter is fixed on the motor stator 6.

[0093] Although the sensor principle is similar to that of an ordinary encoder, the displacement sensor provided in this embodiment can significantly reduce the structural volume through a more compact structural layout, and cleverly integrates the entire photoelectric structure with the galvanometer motor. For example, the encoder's separate housing, bearings, oil seals and other structures are eliminated, and it is directly packaged at the rear of the motor, such as Figure 1 and Figure 2 As shown, the displacement sensor is integrated into the motor housing 7 and connected to the circuit board 8 on the galvanometer motor. At the same time, the photoelectric converter is directly fixed on the motor stator, which can greatly reduce the volume occupied by the sensor.

[0094] Figure 3 A schematic flow chart of an assembly method of a displacement sensor provided in an embodiment of the present invention is provided. The assembly method is applied to the displacement sensor described above, and the assembly method includes steps S101 to S104.

[0095] Step S101: fix the code disc tray on the motor shaft, and place the grating code disc on the disc surface of the code disc tray;

[0096] Step S102, controlling the motor shaft to rotate at a constant speed, and detecting whether the rotation center of the grating code disk is concentric with the rotation center of the motor shaft;

[0097] Step S103: When the rotation center of the grating code disk is not concentric with the rotation center of the motor shaft, monitoring the jitter of the grating code disk from the edge of the grating code disk;

[0098] Step S104 : correcting the grating code disk based on the jitter of the grating code disk so that the rotation center of the grating code disk is concentric with the rotation center of the motor shaft.

[0099] This embodiment utilizes a specialized assembly process to improve the concentricity of the grating code disk and the motor shaft, thereby enhancing overall structural accuracy. The concentricity of the grating code disk and the motor shaft of a structural sensor is a crucial factor affecting displacement measurement accuracy. Traditional direct connection methods can easily cause the motor shaft and the encoder code disk's rotational center to be misaligned, leading to significant position errors and precision loss. Therefore, this embodiment incorporates a corresponding assembly process based on the structural sensor to ensure concentricity between the grating code disk and the motor shaft.

[0100] Specifically, the code disc tray is first fixed to the motor shaft, glue is applied to the tray surface, and then the grating code disc is placed. The motor shaft is then rotated at a constant speed. At this time, the rotation centers of the motor shaft and the grating code disc are observed to be concentric. Here, if the rotation center of the grating code disc is not concentric with the rotation center of the motor shaft, then when looking down at the edge of the grating code disc, it will be observed that the edge of the grating code disc does not stay in the same position, but jumps up and down with the rotation. Therefore, in practical applications, a CCD camera or laser displacement sensor can be used to align the edge of the grating code disc, monitor its jump, and correct and adjust the jump to significantly reduce it until the camera can no longer observe the jump. The corrected structure can be fixed by methods such as glue curing to form a perfectly concentric mechanism.

[0101] An embodiment of the present invention further provides a galvanometer motor system, comprising the displacement sensor described above.

[0102] Further, such as Figure 4 As shown, an embodiment of the present invention further provides a signal processing method for a galvanometer motor system. The signal processing method is applied to the galvanometer motor system as described above. The signal processing method includes steps S201 to S204.

[0103] Step S201: Acquire an optical signal of a target object and convert the optical signal into a digital signal;

[0104] Step S202: performing bias conditioning and amplitude conditioning on the digital signal to obtain a target signal;

[0105] Step S203: performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information;

[0106] Step S204: Pack and output the location information according to a set format.

[0107] In this embodiment, an optical signal is first acquired and converted into a digital signal. The digital signal is then compensated and conditioned through bias and amplitude conditioning to obtain a corresponding target signal. This target signal is then segmented and processed to obtain the position information corresponding to the optical signal. This position information is then packaged into coded information in a specific format to enhance its anti-interference performance, and finally, the position information is output. This signal processing process significantly improves the signal processing efficiency and accuracy of the galvanometer motor system, as well as its anti-interference capability.

[0108] In a specific embodiment, acquiring an optical signal of a target object and converting the optical signal into a digital signal includes:

[0109] Converting the optical signal into an electrical signal using a photoelectric converter;

[0110] Amplifying the electrical signal through an analog amplification circuit to obtain an analog signal;

[0111] The analog information is converted into digital form to obtain the digital signal.

[0112] After acquiring the optical signal, the optical signal is first converted into a weak electrical signal through a photoelectric converter, and then the weak electrical signal is converted into a measurable signal through an analog amplifier, and then the analog signal is converted into a digital signal through analog-to-digital conversion, that is, the digital signal.

[0113] In another specific embodiment, after the step of performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information, the following steps are included:

[0114] The position information is filtered.

[0115] After obtaining the position information, a filter can be used to filter it to remove interference information caused by the optical path and circuit, thereby smoothing the position. After that, the filtered position information can be packaged.

[0116] In one embodiment, performing bias conditioning and amplitude conditioning on the digital signal to obtain a target signal includes:

[0117] Obtaining a voltage sine cycle of the digital signal;

[0118] Sampling the maximum voltage and the minimum voltage in the sinusoidal cycle;

[0119] According to the following formula, a bias voltage is calculated in combination with a set voltage, and the bias voltage is used to perform bias conditioning on the digital signal;

[0120] COMPEN = RAW-(TAR_CEN-((MAX-MIN) / 2+MIN));

[0121] Where COMPEN represents the bias-adjusted voltage, RAW represents the raw input voltage, TAR_CEN represents the set voltage, MAX represents the maximum voltage, MIN represents the minimum voltage, and TAR_CEN-((MAX-MIN) / 2+MIN) represents the bias voltage.

[0122] Furthermore, the step of performing bias adjustment and amplitude adjustment on the digital signal to obtain a target signal further includes:

[0123] According to the following formula, a gain ratio is calculated in combination with a preset standard signal peak-to-peak value, and the digital signal is amplitude conditioned according to the gain ratio;

[0124] OUT = ((MAX-MIN) / STAD)*RAW;

[0125] Where OUT is the amplitude-adjusted voltage, STAD is the peak-to-peak value of the standard signal, and (MAX - MIN) / STAD is the gain ratio.

[0126] Due to factors such as dust, oil, and LED light intensity attenuation, the quality of the electrical signal can vary slightly with changing operating environments, affecting positioning accuracy. Therefore, to compensate for signal attenuation and offset, this embodiment employs both bias and amplitude conditioning.

[0127] When performing bias compensation, the maximum and minimum values of each sinusoidal cycle of the converted digital signal are sampled, and the center voltage (MAX-MIN) / 2+MIN is obtained based on the maximum and minimum values. The offset is then obtained by subtracting it from the set voltage, and this value is subtracted from the original signal to achieve compensation for the bias voltage.

[0128] When performing amplitude compensation, the peak-to-peak voltage MAX-MIN can be calculated based on the maximum and minimum values, and then divided by the standard voltage amplitude to obtain its gain ratio. Combined with the original voltage, the gain-compensated voltage can be obtained.

[0129] Through the above two compensation methods, the quality and consistency of the signal can be greatly improved, thereby providing reliable guarantee for subsequent positioning accuracy and ensuring that the system can operate stably in different environments.

[0130] The set voltage can be adaptively adjusted based on environmental changes, further optimizing the displacement sensor's performance. This adaptive adjustment mechanism monitors the system's operating status in real time and dynamically adjusts the set voltage as needed to adapt to varying operating environments and conditions. For example, in the presence of contaminants such as dust or oil, the system can automatically increase the set voltage to compensate for signal attenuation, ensuring signal accuracy and stability. Furthermore, the mechanism automatically adjusts the gain ratio based on the attenuation of LED light intensity, maintaining high-quality signal transmission. This adaptive adjustment feature not only improves the system's robustness and reliability, but also reduces maintenance costs, enabling the system to operate stably in a variety of complex environments.

[0131] In some optional embodiments, the set voltage is obtained by an adaptive binary voltage regulation algorithm. Specifically, it includes: first presetting a target voltage V target , and define the allowable error range Δe, for example ±0.1%. Then continuously collect the output voltage V of multiple groups of galvanometer motor systems output And the corresponding adjustment step D, then calculate the current error e=V target -V output At the same time, the V-D characteristic curve is fitted by the least square method, and a linear relationship model between the output voltage and the regulation amount is established:

[0132] V output =k1*D+b;

[0133] Among them, k1 is the slope and b is the intercept, which can be understood as the adjustment sensitivity. Through this linear relationship model, V output After that, the corresponding adjustment step D is calculated;

[0134] Dynamically adjust the step size ΔD according to the current error e:

[0135] ΔD=k2*|e|+k3*de / dt;

[0136] Here, k2 is the proportional coefficient and k3 is the differential coefficient. For large errors, rapid response is prioritized, while for small errors, stable convergence is emphasized. If two consecutive adjustments are made in the same direction, the step size is reduced to 50% of the original value.

[0137] Then, the adjustment amount is updated according to the error direction:

[0138] If e>0, then increase the adjustment compensation, that is, D new =D current +ΔD; where D current is the most recent adjustment step;

[0139] If e<0, then reduce the adjustment compensation, that is, D new =Dcurrent +ΔD.

[0140] When the error e is within the allowable error range Δe, the iteration is stopped, and the adjustment step size at this time is set as the target step size, and the set voltage is obtained by combining the target voltage: V = V target +D new This allows the set voltage to better meet actual operating requirements and prevents voltage fluctuations from affecting the accuracy of the displacement sensor. Furthermore, the adaptive binary voltage regulation algorithm can dynamically adjust based on the real-time operating status of the galvanometer motor system, ensuring the system is always in optimal working condition.

[0141] In other optional embodiments, the peak-to-peak value of the standard signal is set using a differential threshold detection method. Specifically, the method includes first acquiring an optical signal and converting it into a digital signal (represented here as S(t), where t represents time). High-frequency noise (such as glitches) is then eliminated using a mean filter, median filter, or low-pass filter. The effects of baseline drift are also eliminated by subtracting the signal mean or moving average. Next, a first-order difference calculation is performed, i.e., a forward difference sequence ΔS(t) = S(t-1) - S(t) is calculated for S(t) to reflect changes in the signal slope. Extreme value candidate points are then screened, where a peak is defined as a point where the differential value changes from positive to negative, i.e., ΔS(t) > 0 and ΔS(t+1) < 0, and a trough is defined as a point where the differential value changes from negative to positive, i.e., ΔS(t) < 0 and ΔS(t+1) > 0. Set a dynamic threshold based on the signal characteristics. For example, take the mean μ and standard deviation σ within the differential absolute value sliding window, and use this setting to set the adaptive threshold: T=μ+k4σ, where k4 is the empirical coefficient. Here, if the absolute value of the difference between the two sides of the extreme candidate point is less than the threshold T, it is considered as noise interference and is removed. At the same time, the symbolic approximate matching method is combined to exclude the interference segment. Then retain the set of peaks and troughs that pass the threshold screening, and select the maximum value V in the peak from the set. max and the minimum value V in the trough min , thus obtaining the standard signal peak-to-peak value V pp =V max -V min .

[0142] In one embodiment, performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information includes:

[0143] Obtaining a sinusoidal period of the target signal, and extracting a first sinusoidal signal and a second sinusoidal signal having a phase difference of 90° from the sinusoidal period of the target signal;

[0144] Performing polar coordinate conversion on the first sinusoidal signal and the second sinusoidal signal, and forming a Lissajous circle based on the fluctuation periods of the first sinusoidal signal and the second sinusoidal signal;

[0145] According to the following formula, for any point on the Lissajous circle, the corresponding angle information is calculated:

[0146] α=atan (Y / X) = atan (B / A);

[0147] Wherein, α represents angle information, atan represents the inverse tangent trigonometric function, A represents the first sine signal, B represents the second sine information, and X and Y represent the coordinates of any point on the Lissajous circle;

[0148] The position information is calculated by combining the angle information according to the following formula:

[0149] P = (N*M) + α / 360*N;

[0150] Where P represents the position information, N represents the subdivision ratio, and M represents the number of sine cycles.

[0151] In traditional solutions, even if the signal is subdivided, the subdivision ratio generally does not exceed 16 times. In other words, a sine wave can usually only generate 16 pulses. However, due to the extremely high precision of the galvanometer, the required subdivision ratio must be above 8192, that is, each sine wave cycle needs to generate 8192 position data or pulses. Therefore, a more sophisticated solution must be adopted to achieve this function. Therefore, this embodiment uses a subdivision algorithm to perform position calculations on the target signal to meet actual usage requirements.

[0152] In this embodiment, first, an A-phase sinusoidal signal and a B-phase sinusoidal signal with a phase difference of 90° are obtained according to the target signal, namely the first sinusoidal signal and the second sinusoidal signal. Since the waveforms of the ideal A-phase sinusoidal signal and the B-phase sinusoidal signal are consistent and the signals differ by 90°, after polar coordinate transformation, in the polar coordinate system, the A-phase sinusoidal signal and the B-phase sinusoidal signal fluctuate for a complete cycle to form a complete circle, namely the Lissajous circle. Furthermore, through inverse trigonometric function calculations, the corresponding angle information of any point on the circle can be calculated based on the X and Y coordinates, and this angle information is unique within each sinusoidal wave cycle. Then, the angle information of multiple cycles is accumulated to generate detailed position information.

[0153] The angle calculation formula is: α = atan (Y / X) = atan (B / A). α is the angle of a single sine cycle, B is the amplitude of the B-phase sinusoidal signal, A is the amplitude of the A-phase sinusoidal signal, and atan is the inverse tangent trigonometric function.

[0154] Correspondingly, the calculation formula for the position information is: Position P = (8192*number of sine cycles) + α / 360*8192, that is, the corresponding position information can be obtained through the above angle calculation formula and position calculation formula.

[0155] In one embodiment, the step of acquiring an optical signal from a target object and converting the optical signal into a digital signal further includes:

[0156] Comparing the optical signal with a preset first signal amplitude and a second signal amplitude, respectively; wherein the first signal amplitude is higher than the second signal amplitude;

[0157] When the optical signal exceeds the first signal amplitude, the base of the photoelectric receiver is step-cut to expand the gap between the grating code disk and the photoelectric converter;

[0158] When the optical signal is lower than the second signal amplitude, a spacer is inserted between the grating code disk and the photoelectric converter to reduce the gap between the grating code disk and the photoelectric converter.

[0159] Signal conditioning is divided into coarse and fine tuning. The aforementioned signal compensation and subdivision procedures fall under fine tuning. To further improve signal conditioning accuracy, this embodiment also performs coarse signal tuning. Because light interference fringes are highly sensitive to changes in position, even slight changes in the displacement of the code disk and photoelectric converter can lead to significant changes in the strength of the interference fringe signal, which in turn can affect the electrical signal and subdivision accuracy. Therefore, by coarsely adjusting the gap between the grating code disk and the photoelectric converter, the resulting electrical signal amplitude deviation can be kept within 0.1V.

[0160] For example, when the signal amplitude is too high, the photoelectric receiver base can be cut with a file in 0.05mm increments to increase the gap between the code disk and the photoelectric converter, thereby reducing the light intensity and reducing the electrical signal amplitude. When the signal amplitude is too low, a spacer (with thickness grades of 0.025mm, 0.05mm, and 0.1mm) can be inserted between the grating code disk and the photoelectric converter to reduce the gap, thereby increasing the light intensity signal and enhancing the electrical signal amplitude.

[0161] In one embodiment, when the packaged position information is output externally, a dedicated high-speed communication protocol can be used. The high-speed position transmission protocol dedicated to the galvanometer is mainly used to minimize transmission delay, avoid interference, and identify bit errors.

[0162] This embodiment adopts digital differential transmission at the physical layer for anti-interference, especially for the suppression of common-mode interference, with obvious effects and obvious advantages over traditional analog transmission methods. During actual transmission, a clock rate greater than or equal to 10 MHz is used for data transmission. Full-duplex communication is adopted, that is, sending and receiving are carried out simultaneously, so that the signal processing device can simultaneously complete the request for sending the next frame position information and receiving the current position information. Compared with the common 2.5 MHz half-duplex communication on the market, not only the signal transmission frequency is increased by more than 4 times, but also the single-line communication mode of question and answer is avoided, and the efficiency is at least doubled again, so the overall efficiency is increased by more than 8 times.

[0163] In addition, CRC and packet sequence number verification mechanisms can be used to ensure that each frame of data is trustworthy. At the same time, different function frames can be clearly distinguished. Compared with the pulse transmission method that cannot identify the source of the pulse, this greatly reduces the bit error rate and cumulative error.

[0164] In an actual application scenario, the performance test and verification of the galvanometer motor system provided by this embodiment is carried out, such as Figure 5-Figure 7 As shown, Figure 5 is the Lissajous circle without bias compensation, Figure 6 is the Lissajous circle without gain compensation, Figure 7 This is the effect after compensation. As you can see, Figure 7 After offset and amplitude calibration, the Lissajous circle, used for segmentation, achieves optimal values for both the A-phase and B-phase sinusoidal signals. This significantly improves signal quality and uniformly corrects errors introduced by various steps in the production process, significantly contributing to improved product consistency.

[0165] In addition, the parameter comparison between the galvanometer motor system provided in this embodiment and the general servo motor is shown in Table 1:

[0166] Table 1

[0167]

[0168] As can be seen from Table 1, the galvanometer motor system provided by this embodiment exhibits significant advantages in single-turn resolution, signal calibration, volume, and single-frame position information communication rate. In particular, this embodiment achieves 23 bits of single-turn resolution, meaning that each sine wave cycle can generate 8192 pieces of position data or pulses. This far exceeds the 11-bit resolution of existing servo motors, thereby achieving higher positioning accuracy and more refined control.

[0169] In summary, this embodiment develops a unique set of structural sensors for the galvanometer motor system, successfully achieving the following technical effects:

[0170] (1) Reduced size: By optimizing the design and adopting advanced manufacturing processes, the overall size of the encoder is significantly reduced, making it more compact and thus better adapted to the limited space of the galvanometer motor;

[0171] (2) Improve position segmentation accuracy: By adopting high-resolution sensors and sophisticated signal processing algorithms, the position segmentation accuracy is significantly improved, ensuring high-precision positioning and motion control of the galvanometer motor;

[0172] (3) Improved speed and anti-interference capability: By improving signal transmission technology and enhancing electromagnetic compatibility design, the encoder's transmission speed has been significantly improved. At the same time, it has stronger anti-interference capability, ensuring stable operation even in complex electromagnetic environments.

[0173] In summary, the structural sensor provided in this embodiment not only meets the stringent requirements of the galvanometer motor system on volume, accuracy, speed, and anti-interference, but also provides strong technical support for the high-performance application of the galvanometer motor system.

[0174] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of the claims of this application.

[0175] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. A galvanometer motor system, characterized in that: The displacement sensor is connected to the motor shaft and adopts a transmission grating sandwich structure. The transmission grating sandwich structure includes: A light source module is provided on the upper layer, wherein the light source module includes an aspheric collimating lens capable of generating a uniform parallel light beam; The grating code disk is arranged in the middle layer. The grating code disk is made of an optical glass substrate and is fixed on the motor shaft through a code disk tray. A photoelectric receiving module is provided on the lower layer. The photoelectric receiving module includes multiple groups of orthogonally arranged photodiodes and photoelectric converters. The photoelectric converters are fixed to the motor stator. The photodiodes are used to receive the brightness changes of the light stripes and form optical signals. The photoelectric converters are used to receive the optical signals and convert them into electrical signals. The signal processing method of the galvanometer motor system includes: Acquire an optical signal of a target object and convert the optical signal into a digital signal; performing bias conditioning and amplitude conditioning on the digital signal to obtain a target signal; Performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information; Packing and outputting the location information according to a set format; The step of acquiring an optical signal of a target object and converting the optical signal into a digital signal includes: Comparing the optical signal with a preset first signal amplitude and a second signal amplitude, respectively; wherein the first signal amplitude is higher than the second signal amplitude; When the optical signal exceeds the first signal amplitude, the base of the photoelectric receiver is step-cut to expand the gap between the grating code disk and the photoelectric converter; When the optical signal is lower than the second signal amplitude, a spacer is inserted between the grating code disk and the photoelectric converter to reduce the gap between the grating code disk and the photoelectric converter.

2. A signal processing method for a galvanometer motor system, applied to the galvanometer motor system according to claim 1, characterized in that: The signal processing method comprises: Acquire an optical signal of a target object and convert the optical signal into a digital signal; performing bias conditioning and amplitude conditioning on the digital signal to obtain a target signal; Performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information; Packing and outputting the location information according to a set format; The step of acquiring an optical signal of a target object and converting the optical signal into a digital signal includes: Comparing the optical signal with a preset first signal amplitude and a second signal amplitude, respectively; wherein the first signal amplitude is higher than the second signal amplitude; When the optical signal exceeds the first signal amplitude, the base of the photoelectric receiver is step-cut to expand the gap between the grating code disk and the photoelectric converter; When the optical signal is lower than the second signal amplitude, a spacer is inserted between the grating code disk and the photoelectric converter to reduce the gap between the grating code disk and the photoelectric converter.

3. The signal processing method of the galvanometer motor system according to claim 2, characterized in that: The step of acquiring an optical signal of a target object and converting the optical signal into a digital signal includes: Converting the optical signal into an electrical signal using a photoelectric converter; Amplifying the electrical signal through an analog amplification circuit to obtain an analog signal; Perform digital conversion on the analog signal to obtain the digital signal.

4. The signal processing method of the galvanometer motor system according to claim 2, characterized in that: The performing bias conditioning and amplitude conditioning on the digital signal to obtain a target signal includes: Obtaining a voltage sine cycle of the digital signal; Sampling the maximum voltage and the minimum voltage in the sinusoidal cycle; According to the following formula, a bias voltage is calculated in combination with a set voltage, and the bias voltage is used to perform bias conditioning on the digital signal; COMPEN = RAW-(TAR_CEN-((MAX-MIN) / 2+MIN)); Where COMPEN represents the bias-adjusted voltage, RAW represents the raw input voltage, TAR_CEN represents the set voltage, MAX represents the maximum voltage, MIN represents the minimum voltage, and TAR_CEN-((MAX-MIN) / 2+MIN) represents the bias voltage.

5. The signal processing method of the galvanometer motor system according to claim 4, characterized in that: The step of performing bias conditioning and amplitude conditioning on the digital signal to obtain a target signal further includes: According to the following formula, a gain ratio is calculated in combination with a preset standard signal peak-to-peak value, and the digital signal is amplitude conditioned according to the gain ratio; OUT = ((MAX-MIN) / STAD)*RAW; Where OUT is the amplitude-adjusted voltage, STAD is the peak-to-peak value of the standard signal, and (MAX - MIN) / STAD is the gain ratio.

6. The signal processing method of the galvanometer motor system according to claim 2, characterized in that: The performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information includes: Obtaining a sinusoidal period of the target signal, and extracting a first sinusoidal signal and a second sinusoidal signal having a phase difference of 90° from the sinusoidal period of the target signal; Performing polar coordinate conversion on the first sinusoidal signal and the second sinusoidal signal, and forming a Lissajous circle based on the fluctuation periods of the first sinusoidal signal and the second sinusoidal signal; According to the following formula, for any point on the Lissajous circle, the corresponding angle information is calculated: α=atan (Y / X) = atan (B / A); Wherein, α represents angle information, atan represents the inverse tangent trigonometric function, A represents the first sine signal, B represents the second sine information, and X and Y represent the coordinates of any point on the Lissajous circle; The position information is calculated by combining the angle information according to the following formula: P = (N*M) + α / 360*N; Where P represents the position information, N represents the subdivision ratio, and M represents the number of sine cycles.

7. The signal processing method of the galvanometer motor system according to claim 2, characterized in that: After the step of performing position calculation on the target signal using a subdivision algorithm to obtain corresponding position information, the method further includes: The position information is filtered.

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