A method for improving the anti-interference capability of a control board

Abstract

The present application relates to the technical field of control board signal processing, and provides a method for improving the anti-interference capability of a control board, frequency characteristics of each motor control signal in the control board are collected, a frequency spectrum is obtained by performing Fourier analysis on the frequency characteristics, and the control signals are divided into a high-frequency signal group and a low-frequency signal group according to the frequency spectrum; time slot allocation is performed on the control signals in the high-frequency signal group, the transmission cycle of the high-frequency signal group is divided into N time slots, and each control signal occupies one time slot; based on the frequency characteristics of the low-frequency signal group, an orthogonal modulation base vector is constructed, and the control signals of the low-frequency signal group are mapped onto the orthogonal modulation base vector; and according to the time slot allocation scheme and the orthogonal modulation base vector, the signal transmission timing of the control board is reconstructed, so that the control signals of the high-frequency signal group and the low-frequency signal group do not interfere with each other. The technical problem that the control precision is reduced due to mutual interference of the control signals when the control board is in operation with multiple motors is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of control board signal processing, in particular to a method for improving the anti-interference capability of a control board. BACKGROUND

[0002] With the rapid development of industrial automation and intelligent control technology, control boards, as the core control units in multi-motor systems, are widely used in fields such as numerical control machine tools, robots, and rail transit. The main function of a control board is to monitor and accurately control the running state of multiple motors, and its performance directly affects the stability and efficiency of the entire system. However, as the complexity of multi-motor systems continues to increase, the types and quantities of control signals that control boards need to process have significantly increased, and these signals often have different frequency characteristics and real-time requirements. During signal transmission and processing, due to the cross-interference between multiple control signals, especially the coupling interference between high-frequency signals and low-frequency signals, signal distortion and bit error rate increase, which reduces control accuracy and even causes system operation failure. In the prior art, research on the anti-interference capability of control boards mainly focuses on hardware optimization and simple signal filtering, such as shielding design, signal shielding cable, or adding filter capacitors to suppress the influence of external electromagnetic interference. However, the anti-interference effect of these methods is still limited in a complex multi-signal interaction environment, especially in multi-motor systems, where the interference problem between internal signals cannot be completely solved by simply optimizing the hardware.

[0003] Some research in the prior art attempts to improve the anti-interference capability from the perspective of signal grouping and transmission protocol optimization. For example, by assigning priorities to control signals or using time division multiplexing technology to reduce conflict interference between signals. However, these methods still have the following shortcomings when dealing with mixed transmission of high-frequency and low-frequency signals: first, priority assignment can only partially alleviate the conflict problem, but cannot effectively separate the timing interference of high-frequency signals; second, traditional time division multiplexing methods lack optimization design for signal frequency characteristics, and time slot resource allocation is not efficient enough to meet the high requirements of multi-motor systems for real-time performance and accuracy; in addition, low-frequency signals are easily affected by coupling interference from high-frequency signals in a multi-signal transmission environment, resulting in a decline in signal quality. These technical bottlenecks indicate that there is still much room for improvement in the analysis of signal frequency characteristics and interference suppression design in the prior art. How to improve the anti-interference capability of control boards through more refined signal grouping and transmission strategies has become an important direction of current research. SUMMARY

[0004] Embodiments of the present application provide a method for improving the anti-interference capability of a control board, which can at least partially solve the technical problem of control board performance degradation due to mutual interference between control signals when multiple motors are running simultaneously.

[0005] Other features and advantages of the present application will be apparent from the detailed description that follows, or can be learned by practice of the present application.

[0006] According to one aspect of the present application, there is provided a method for improving anti-interference capability of a control board, comprising:

[0007] Collecting frequency characteristics of motor control signals in the control board, performing Fourier analysis on the frequency characteristics to obtain a frequency spectrum, and dividing the control signals into a high-frequency signal group and a low-frequency signal group according to the frequency spectrum;

[0008] Performing time slot allocation on the control signals in the high-frequency signal group, dividing a transmission period of the high-frequency signal group into N time slots, N being the number of signals in the high-frequency signal group, and each control signal occupying one time slot exclusively;

[0009] Based on the frequency characteristics of the low-frequency signal group, constructing an orthogonal modulation basis vector, and mapping the control signals of the low-frequency signal group onto the orthogonal modulation basis vector;

[0010] According to the time slot allocation scheme and the orthogonal modulation basis vector, reconstructing the signal transmission timing of the control board, so that the control signals of the high-frequency signal group and the low-frequency signal group do not interfere with each other.

[0011] In the present application, based on the foregoing scheme, the main frequency component of the signal is identified by an adaptive threshold detection algorithm according to the signal energy distribution characteristics in the frequency spectrum;

[0012] The detection logic of the adaptive threshold detection algorithm is as follows:

[0013] Calculate the energy values of the frequency components in the frequency spectrum, and arrange the energy values in descending order to obtain an energy sequence;

[0014] When the frequency spectrum has an energy aggregation area, use the region growing method to determine the main frequency bandwidth;

[0015] When the energy distribution of the frequency spectrum is relatively dispersed, use the iterative threshold method to identify the main frequency;

[0016] When there are multiple frequency components with similar energy, calculate the energy ratio between each frequency component, and if the ratio of the largest energy component to the second largest energy component is less than a first preset value, then these frequency components are all identified as main frequency components;

[0017] When the signal has a frequency drift phenomenon, obtain a time-frequency graph by calculating the short-time Fourier transform, dynamically track the main frequency component, and if the frequency drift exceeds a first preset percentage of the center frequency, then re-identify the main frequency;

[0018] After the main frequency recognition is completed, an energy proportion of the main frequency component is calculated, and a frequency range with an energy proportion exceeding a second preset percentage of total energy is determined as a final main frequency bandwidth.

[0019] In the application, based on the foregoing scheme, the time slot allocation comprises:

[0020] Priority information of each control signal in the high-frequency signal group is acquired; the priority information comprises real-time requirement and control accuracy requirement of the signal;

[0021] When the real-time requirement of a certain control signal is higher than a second preset value, the certain control signal is marked as the highest priority, and the time slot is preferentially allocated; when there are multiple control signals with the same priority, the time slot is grouped according to bandwidth requirements of the signals, and the signals with similar bandwidth requirements are arranged in adjacent time slots;

[0022] In the time slot allocation, a dynamic time slot reservation mechanism is adopted; when signal transmission in a certain time slot is completed in advance, the remaining time is allocated to an adjacent time slot with data backlog through a time slot multiplexing mechanism.

[0023] In the application, based on the foregoing scheme, during implementation of the dynamic time slot reservation mechanism, a sliding window is established to record transmission states of each signal.

[0024] When data overflow occurs in a certain control signal in the sliding window, the amount of data overflowed and the duration are recorded;

[0025] If the number of data overflows exceeds 3 times and the amount of data overflowed in a single time exceeds a third preset percentage of the buffer capacity, a time slot reservation program is triggered;

[0026] The time slot reservation program comprises:

[0027] A standby time slot is preferentially reserved after the exclusive time slot of the signal; if the subsequent time slot is occupied, a time slot compression algorithm is used to recombine the existing time slots, and the duration of all time slots is uniformly compressed by one-tenth to free up an additional standby time slot; when the reserved time slot is not used for 5 transmission periods, the reserved time slot is automatically recycled; if data overflow of the signal continues to occur after the reserved time slot is obtained, the signal is marked as an abnormal state, and a signal bandwidth reestimation program is started.

[0028] In the application, based on the foregoing scheme, actual use of each time slot is detected in real time, and when it is detected that a time slot completes data transmission in advance and the remaining time exceeds a preset time, the time slot multiplexing mechanism is triggered.

[0029] The time slot allocation further comprises a time slot reallocation mechanism.

[0030] When a control signal does not arrive on time for 3 consecutive transmission periods, a time slot re-allocation mechanism is executed;

[0031] Before time slot re-allocation, the bandwidth requirements of all active signals are re-evaluated; when there are multiple signals requesting time slot re-allocation, a re-allocation priority queue is established according to the priority of the signals and the data backlog; if a signal obtains a re-allocated time slot, its original time slot is temporarily marked as a standby state; when the original signal resumes normal transmission, the original time slot allocation scheme is restored at the beginning of the next transmission period; if the original signal continues to be abnormal for more than 10 transmission periods, a permanent re-allocation program is started to reconfigure the entire time slot allocation scheme.

[0032] In the application, based on the foregoing scheme, constructing the orthogonal modulation basis vector includes:

[0033] Performing spectrum analysis on all control signals in the low-frequency signal group to obtain the bandwidth characteristics and frequency distribution of each signal;

[0034] An initial orthogonal basis is constructed by using the Schmidt orthogonalization method, and a signal with the maximum spectral energy is selected as the first basis vector;

[0035] The initial orthogonal basis is optimized, and the direction and amplitude of the basis vector are adjusted by the minimum mean square error criterion;

[0036] After the basis vector is constructed, the orthogonality between the basis vectors is calculated, and if the orthogonality is lower than a first preset threshold, a correction term is introduced for fine tuning until the orthogonality requirement is met.

[0037] In the application, based on the foregoing scheme, adjusting the direction and amplitude of the basis vector by the minimum mean square error criterion includes:

[0038] An error objective function is established, and the mean square error between the original signal and the basis vector reconstructed signal is taken as the optimization target;

[0039] The weight coefficient of each basis vector is calculated, and if the weight coefficient of a basis vector is less than a second preset threshold, the basis vector is marked as an optimization object;

[0040] The optimization object is adjusted in direction and amplitude.

[0041] In the application, based on the foregoing scheme, the adjustment direction includes:

[0042] The angle between each basis vector and the error vector is calculated; when the angle is greater than a preset threshold, the adjustment direction is determined according to the error size; each time the basis vector is adjusted, the direction of the basis vector is offset towards the error vector, and the offset amount is determined by the error size and a fixed adjustment coefficient;

[0043] After each adjustment, check whether the adjusted base vector meets the following constraint conditions:

[0044] The orthogonality between the base vectors is not less than a third preset threshold, the deviation angle from the original direction is not more than 45 degrees, and the signal reconstruction error after adjustment is less than the error before adjustment;

[0045] If any constraint condition is violated, the adjustment amount needs to be limited, and the specific limiting method is:

[0046] When the orthogonality does not meet the requirement, the adjustment amount is projected along the direction that maintains the orthogonality; when the deviation angle is too large, the adjustment amount is limited within the maximum allowed range; and when the reconstruction error increases, the adjustment amount is proportionally reduced.

[0047] According to another aspect of the present application, a system for improving the anti-interference capability of a control board is provided, comprising:

[0048] A collection module is configured to collect frequency characteristics of motor control signals in the control board;

[0049] A spectrum division module is configured to perform Fourier analysis on the frequency characteristics to obtain a spectrum diagram, and divide the control signals into a high-frequency signal group and a low-frequency signal group according to the spectrum diagram;

[0050] A time slot allocation module is configured to allocate time slots to the control signals in the high-frequency signal group, divide the transmission period of the high-frequency signal group into N time slots, and each control signal occupies one time slot, where N is the number of signals in the high-frequency signal group;

[0051] A mapping module is configured to construct orthogonal modulation base vectors based on the frequency characteristics of the low-frequency signal group, and map the control signals of the low-frequency signal group to the orthogonal modulation base vectors;

[0052] A signal reconstruction module is configured to reconstruct the signal transmission timing of the control board according to the time slot allocation scheme and the orthogonal modulation base vectors, so that the control signals of the high-frequency signal group and the low-frequency signal group do not interfere with each other.

[0053] In the technical scheme of the present application, the frequency characteristics of each motor control signal in the control panel are collected, the signal spectrum is classified by using Fourier analysis, the control signals are divided into a high-frequency signal group and a low-frequency signal group, and different interference suppression strategies are adopted for signal groups with different frequency characteristics. By allocating time slots to the high-frequency signal group, the independent occupation of time slots by signals is realized, effectively avoiding the superposition of high-frequency interference; at the same time, based on the frequency characteristics of the low-frequency signal group, an orthogonal modulation basis vector is constructed to map the low-frequency signals, ensuring good orthogonality between low-frequency signals and avoiding mutual interference. In addition, by reconstructing the signal transmission timing, the isolation of high and low frequency signals and the resource utilization efficiency are further optimized. Compared with the prior art, the present application can solve the technical problem that the control precision of the control panel is reduced due to mutual interference of control signals when multiple motors are running at the same time, not only significantly improving the anti-interference ability of the control panel in a complex multi-signal environment, but also ensuring the real-time and precision of signal transmission, especially suitable for multi-motor control, high-precision industrial automation and other fields.

[0054] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0055] The accompanying drawings, which are incorporated into and form part of the specification, illustrate an embodiment consistent with the present application and, together with the specification, serve to explain the principles of the application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained from these drawings without creative labor for those skilled in the art.

[0056] Figure 1 The flowchart of the method for improving the anti-interference ability of the control panel in an embodiment of the present application is schematically shown. DETAILED DESCRIPTION

[0057] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations, however, can be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the example implementations to those skilled in the art.

[0058] Moreover, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the claimed application. One skilled in the relevant art will recognize, however, that the application can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the application.

[0059] The implementation details of the technical solutions of the application are described in detail as follows:

[0060] Figure 1 A flow chart of a method for improving the anti-interference capability of a control board is shown according to an embodiment of the application. Referring to Figure 1 shown.

[0061] The method for improving the anti-interference capability of a control board according to an embodiment of the application comprises:

[0062] S1: Collecting the frequency characteristics of each motor control signal in the control board, performing Fourier analysis on the frequency characteristics to obtain a frequency spectrum diagram, and dividing the control signals into a high-frequency signal group and a low-frequency signal group according to the frequency spectrum diagram;

[0063] When collecting the frequency characteristics of each motor control signal in the control board, first, the motor control signal is sampled by a 16-bit high-precision analog-to-digital converter on the control board, the sampling frequency is set to 500 kHz, the sampling time window is 100 ms, and the quantization precision of each sampling point is 16 bits. The sampling time window is divided into multiple small windows, and after collecting the data of each small window, data processing is performed.

[0064] During the signal sampling process, the sampling data is temporarily stored by a cache module built in the control board, the storage depth of the cache module is 32 KB; the sampling data temporarily stored in the cache module is preprocessed, the sampling data is windowed by using a Hanning window function, the length of the Hanning window is matched with the number of sampling points; the frequency characteristics after windowing are analyzed by using a 1024-point fast Fourier transform algorithm to generate the frequency spectrum diagram, and the frequency resolution of the frequency spectrum diagram is 500 Hz.

[0065] According to the signal energy distribution characteristics in the spectrum diagram, the main frequency component of the signal is identified by an adaptive threshold detection algorithm, the control signal with a main frequency component greater than 50 kHz is classified into the high-frequency signal group, and the control signal with a main frequency component less than or equal to 50 kHz is classified into the low-frequency signal group; wherein the energy threshold of the main frequency component is dynamically set, the reference value is set to 80% of the total signal energy, and is adaptively adjusted by ±5% according to the signal signal-to-noise ratio; at the same time, the signal quality of the signals in the high-frequency signal group and the low-frequency signal group is evaluated, the signal-to-noise ratio and the harmonic distortion of the signal are calculated, and the signal with a signal-to-noise ratio lower than 20 dB or a harmonic distortion higher than 10% is marked as a key monitoring object.

[0066] The detection logic of the above adaptive threshold detection algorithm is as follows:

[0067] The energy values of each frequency component in the spectrum diagram are calculated, and the energy values are arranged in descending order to obtain an energy sequence; when the spectrum diagram has an obvious energy aggregation area, a region growing method is used to determine the main frequency bandwidth, the energy difference of adjacent frequency points is calculated to determine the bandwidth boundary, and if the energy difference of adjacent frequency points is greater than 30% of the average energy, it is marked as a bandwidth boundary point; for the frequency components in the main frequency bandwidth, the centroid method is used to calculate the main frequency value, and the energy of the frequency component is used as the weight for weighted average.

[0068] When the energy distribution of the spectrum diagram is relatively dispersed, an iterative threshold method is used for main frequency identification, the initial threshold is set to 50% of the maximum spectrum energy, if the number of frequency points higher than the threshold is greater than the expected value, the threshold is increased by 10% for a new iteration, if it is less than the expected value, the threshold is reduced by 10% for a new iteration; when the number of iterations reaches 5 or the number of frequency points meets the expectation, the iteration is stopped and the main frequency component is determined.

[0069] For multiple frequency components with similar energy, the energy ratio between each frequency component is calculated, if the ratio of the maximum energy component to the second largest energy component is less than 1.2, these frequency components are identified as main frequency components; in the identification process, the mean and standard deviation of the background noise are calculated to establish a dynamic threshold criterion, when the energy value of a certain frequency component exceeds the mean of the background noise by more than 3 standard deviations, it is included in the main frequency candidate set; the time domain correlation of the frequency components in the main frequency candidate set is analyzed, the correlation coefficient of the time domain signal corresponding to each frequency component and the original signal is calculated, and the frequency component with a correlation coefficient greater than 0.8 is confirmed as the main frequency component.

[0070] When the signal has frequency drift, the time-frequency diagram is obtained by calculating the short-time Fourier transform to dynamically track the main frequency component, and if the frequency drift exceeds 15% of the center frequency, the main frequency identification is re-performed; after the main frequency identification is completed, the energy proportion of the main frequency component is calculated, and the frequency range with an energy proportion exceeding 80% of the total energy is determined as the final main frequency bandwidth.

[0071] S2: time slot allocation is performed on the control signals in the high-frequency signal group, and the transmission period of the high-frequency signal group is divided into N time slots, N being the number of signals in the high-frequency signal group, and each control signal exclusively occupies one time slot;

[0072] When the time slot allocation is performed on the control signals in the high-frequency signal group, first, the priority information of each control signal in the high-frequency signal group is obtained, and the priority information includes the real-time requirement and control accuracy requirement of the signal; when the real-time requirement of a control signal is higher than 50μs, it is marked as the highest priority, and the time slot is allocated preferentially.

[0073] Further, the transmission period of the high-frequency signal group is planned, the reference transmission period is determined based on the sampling frequency of the highest priority signal, and the reference transmission period is set to 80% of the sampling period of the highest priority signal. The reference transmission period is divided into N time slots, and the duration of each time slot is equal. The number N of time slots is equal to the total number of signals in the high-frequency signal group.

[0074] When there are multiple control signals with the same priority, the time slots are grouped according to the bandwidth requirements of the signals, and the signals with similar bandwidth requirements are arranged in adjacent time slots; when the time slot allocation is performed, a dynamic time slot reservation mechanism is adopted, and if a control signal has data overflow for more than 3 times in the past 10 transmission periods, an additional standby time slot is reserved after its exclusive time slot; when the signal transmission in a time slot is completed in advance, the remaining time is allocated to the adjacent time slot with data backlog through a time slot multiplexing mechanism.

[0075] Before the start of each transmission period, all time slots are aligned through a synchronization signal, and the pulse width of the synchronization signal is 100ns; when it is detected that a control signal fails to arrive in time for 3 consecutive transmission periods, a time slot re-allocation mechanism is started, and the exclusive time slot of the signal is temporarily allocated to other signals with transmission requirements; the transmission quality of the signals in each time slot is monitored in real time, and the bit error rate and the time delay jitter of the signals are calculated; when the bit error rate exceeds 10^-6 or the time delay jitter exceeds 50ns, a time slot adjustment process is triggered; in the time slot adjustment process, the continuity of the signals is ensured through a buffering mechanism, and the signal data to be adjusted is temporarily stored in a buffer, and the transmission is resumed after the new time slot allocation is completed.

[0076] It should be noted that in the implementation process of the dynamic time slot reservation mechanism, a sliding window is first established to record the transmission state of each signal, and the length of the sliding window is 10 transmission periods; when a certain control signal appears data overflow in the sliding window, the amount of data overflow and the duration of data overflow are recorded; if the number of data overflow is more than 3 times and the amount of single overflow data is more than 60% of the buffer capacity, the time slot reservation program is triggered; when the time slot reservation program is triggered, the system reserves a standby time slot after the exclusive time slot of the signal; if the subsequent time slot has been occupied, the existing time slot is reorganized through the time slot compression algorithm, and the duration of all time slots is uniformly compressed by 10%, so as to free up additional standby time slots; when the reserved time slot is not used for 5 transmission periods, the reserved time slot is automatically recycled; if a signal still continuously occurs data overflow after obtaining the reserved time slot, the signal is marked as an abnormal state, and the signal bandwidth reestimation program is started.

[0077] In the implementation of the time slot multiplexing mechanism, the system monitors the actual use of each time slot in real time, and records the idle time of each time slot; when it is detected that a time slot completes data transmission in advance, and the remaining time is more than 100ns, the time slot multiplexing program is triggered immediately; if there is a signal with data backlog in the adjacent time slot, the multiplexing priority is determined according to the amount of backlog data; when multiple signals request to multiplex a free time slot at the same time, the signal with the largest backlog data amount and the longest duration is preferentially allocated; when multiplexing a time slot, a switching protection time of 50ns is set to ensure the reliability of signal switching; if the original signal bursts in the multiplexed time slot, the multiplexing process is terminated immediately to ensure the transmission priority of the original signal; the effect of time slot multiplexing is statistically analyzed to record the multiplexing success rate and the transmission efficiency improvement brought by multiplexing.

[0078] In the implementation of the time slot reallocation mechanism, the system continuously monitors the arrival of each signal; when a certain control signal does not arrive on time for 3 consecutive transmission periods, the state evaluation program is started; if the data amount of the buffer of the signal is less than 20%, the exclusive time slot of the signal is temporarily marked as a reallocation state; before time slot reallocation, the system reevaluates the bandwidth demand of all active signals; when there are multiple signals requesting time slot reallocation, a reallocation priority queue is established according to the priority and data backlog of the signals; if a signal obtains a reallocated time slot, its original time slot will be temporarily marked as a standby state; when the original signal resumes normal transmission, the system will restore the original time slot allocation scheme at the beginning of the next transmission period; if the original signal continues to be abnormal for more than 10 transmission periods, the permanent reallocation program is started to reconstruct the entire time slot allocation scheme; in the process of time slot reallocation, the data transmission continuity is ensured through the double buffering mechanism, and all data to be transmitted will be temporarily stored in the standby buffer.

[0079] It is worth noting that although the above description outlines the general flow of the three time slot mechanisms, the specific implementation details may vary depending on different working environments and their equipment configurations. For example, taking a CNC machine tool machining center as an example, when multiple axes are linked to perform complex curved surface machining tasks, the cooperative operation process of the three mechanisms is as follows:

[0080] When the tool enters the workpiece for heavy cutting, the motor control signal of each axis will change significantly; taking the Z-axis as an example, the sudden change in cutting load causes the data volume of its control signal to increase from 2KB / period under normal working conditions to 3.5KB / period; At this time, the dynamic time slot reservation mechanism responds immediately, detects that the Z-axis has appeared 4 times of data overflow in the last 10 transmission periods, and the overflow amount reaches 75% of the buffer capacity, and immediately reserves a standby time slot behind the Z-axis exclusive time slot; At the same time, since the X-axis and Y-axis are in a low-speed feeding state, their exclusive time slots have 30% to 40% idle time, which is immediately allocated to the data backlog of the Z-axis by the time slot reuse mechanism; When a motor driver is subjected to electromagnetic interference generated by the start and stop of nearby equipment during the machining process, causing continuous interruption of the A-axis feedback signal, the time slot reallocation mechanism quickly responds by temporarily allocating the A-axis time slot to other axes, and after the interference is eliminated, the normal transmission is restored through the double buffering mechanism. In summary, through the cooperative operation of the three mechanisms, the control board exhibits much better anti-interference ability and control precision than traditional control schemes, and is particularly suitable for precision machining fields that require high precision and high reliability. Practice has proved that this scheme can effectively solve various interference problems commonly encountered in industrial sites, and significantly improve the machining quality and production efficiency of the equipment.

[0081] S3: Based on the frequency characteristics of the low-frequency signal group, construct an orthogonal modulation basis vector, and map the control signal of the low-frequency signal group to the orthogonal modulation basis vector;

[0082] When constructing the orthogonal modulation basis vector based on the frequency characteristics of the low-frequency signal group, first, perform frequency spectrum analysis on all control signals in the low-frequency signal group to obtain the bandwidth characteristics and frequency distribution of each signal; After obtaining the frequency characteristics, an initial orthogonal basis is constructed using the Schmidt orthogonalization method, and the signal with the largest spectral energy is selected as the first basis vector; The initial orthogonal basis is optimized, and the direction and amplitude of the basis vector are adjusted to maximize its correlation with the original signal through the least mean square error criterion; When the basis vector is constructed, the orthogonality between the basis vectors is calculated, and if the orthogonality is less than 0.95, a correction term is introduced for fine tuning until the orthogonality requirement is met;

[0083] In the signal mapping, first, the projection coefficient of each control signal and each basis vector is calculated, and the projection coefficient is obtained by the inner product operation of the signal and the basis vector; when the projection coefficient of a certain signal is less than a threshold value, the projection coefficient is amplified by using an adaptive gain control method, and the gain coefficient is limited in the range of 0.5 to 2; the orthogonality of each mapped signal is verified, and the cross-correlation function between the signals is calculated; when the cross-correlation value exceeds 0.1, the compensation factor is introduced for correction; if a certain signal appears distortion in the mapping process, the iterative mapping mechanism is started, and the mapping parameters are gradually adjusted until the distortion degree is reduced to an acceptable range.

[0084] The Schmidt orthogonalization method is used to construct the initial orthogonal basis as follows:

[0085] First, all the signals in the low-frequency signal group are arranged in descending order according to the energy size, and the signal with the largest energy is selected as the first basis vector u1; after the first basis vector is determined, the signal with the second largest energy is selected as the orthogonalization vector v2; the inner product of the orthogonalization vector v2 and u1 is calculated, and the projection component of v2 on u1 is calculated according to the projection formula; v2 is subtracted from the projection component in the direction of u1 to obtain the basis vector u2 orthogonal to u1; after obtaining u2, it is normalized to make the length of the basis vector 1.

[0086] In constructing the third basis vector, the signal with the third largest energy is selected as the orthogonalization vector v3; the inner products of v3 and u1 and u2 are calculated to obtain all the projection components of v3 in the existing basis vector space; v3 is subtracted from all the projection components in the directions of u1 and u2 to obtain the vector u3 orthogonal to the first two basis vectors; if the energy of the obtained u3 is too small (less than 5% of the original signal energy), the current signal is abandoned, and the next signal is selected to repeat the orthogonalization process; when u3 meets the energy requirement, it is normalized.

[0087] The above optimization of the initial orthogonal basis is as follows:

[0088] When the direction and amplitude of the basis vector are adjusted by the least mean square error criterion, first, an error objective function is established, and the mean square error between the original signal and the basis vector reconstruction signal is taken as the optimization target; after the objective function is determined, the weight coefficient of each basis vector is calculated, and the weight coefficient is determined by the correlation degree of the signal and the basis vector; if the weight coefficient of a certain basis vector is less than 0.1, it is marked as an optimization object.

[0089] In the process of direction adjustment, first, the included angle between each base vector and the error vector is calculated; when the included angle is greater than a preset threshold, the adjustment direction is determined according to the error size; in each adjustment, the direction of the base vector is offset towards the error vector, and the offset amount is determined by the error size and a fixed adjustment coefficient; after each adjustment, it is checked whether the adjusted base vector meets the following constraint conditions: the orthogonality between the base vectors is not less than 0.95, the deviation angle from the original direction is not more than 45 degrees, and the signal reconstruction error after adjustment is less than the error before adjustment; if any constraint condition is violated, the adjustment amount needs to be limited, and the specific limiting method is: when the orthogonality does not meet the requirement, the adjustment amount is projected along the direction that maintains the orthogonality; when the deviation angle is too large, the adjustment amount is limited in the maximum allowed range; when the reconstruction error increases, the adjustment amount is proportionally reduced;

[0090] In the process of amplitude adjustment, first, the ideal amplitude value is calculated according to the projection of the signal in the direction of each base vector; when the difference between the actual amplitude and the ideal amplitude exceeds 20%, the amplitude is corrected; in the correction process, the following constraint requirements need to be met: the corrected amplitude should not exceed twice the original signal amplitude, the amplitude ratio between adjacent base vectors should not exceed 5 times, and the distortion of the adjusted signal should not exceed 3%; if the constraint is violated, the following processing method is adopted: when the amplitude is out of limit, it is clamped in the allowed range; when the amplitude ratio is too large, the amplitudes of the related base vectors are adjusted at the same time to meet the ratio requirement; when the distortion exceeds the standard, the maximum adjustment amount that meets the distortion requirement is found through step-by-step backtracking.

[0091] More specifically, the above error objective function can be expressed as follows:

[0092]

[0093] Where E obj represents the optimization objective function, N is the number of signal sampling points, s i is the value of the original signal at the i-th sampling point, w k is the weight coefficient of the k-th base vector, v k (i) is the value of the k-th base vector at the i-th sampling point, K is the total number of base vectors, λ is the orthogonality constraint weight coefficient, <v j ,v k > represents the inner product of the base vector v j and v k .

[0094] It is worth noting that while the above description outlines the general approach to adjusting basis vectors through the least mean square error criterion, specific implementation details may need to be adjusted in accordance with the actual application scenario. For example, when processing sensor signals in an industrial environment, due to the presence of strong electromagnetic interference, the adjustment process of the basis vectors may require more stringent constraint conditions.

[0095] Specifically, assuming that when processing a vibration signal collected in an industrial site containing 2000 sampling points, the system selects 8 basis vectors for signal reconstruction. If it is found that the weight coefficient of the second basis vector is 0.085 (less than the threshold value 0.1), the system will mark it as an object to be optimized. In actual adjustment, if the angle between this basis vector and the error vector is 48 degrees (greater than the preset threshold of 45 degrees), the system will calculate an initial adjustment amount of 0.18. However, due to the interference signals present in the field, this adjustment amount may cause instability in signal reconstruction.

[0096] In this case, the system will more strictly perform constraint checks. For example, if the orthogonality of the adjusted basis vector with the third basis vector drops to 0.94 (lower than the required 0.95), the system will not only project the adjustment amount to the direction of maintaining orthogonality, but also introduce an additional buffer interval, which may further reduce the final adjustment amount to 0.1 to ensure the stability of the system. Similarly, when the amplitude ratio of the fourth and fifth basis vectors reaches 4.8 (close to the allowed upper limit of 5 times), the system will intervene in the adjustment in advance to control the ratio within a more conservative range, such as within 4 times.

[0097] On the other hand, the above description outlines the general process of constructing orthogonal modulation basis vectors and performing signal mapping, but specific implementation details may vary depending on different control system characteristics and application requirements. For example, when processing multiple low-frequency control signals in an industrial control system, due to the different bandwidth requirements and interference sensitivities of different control loops, it may be necessary to design the frequency characteristics of the basis vectors differently.

[0098] Specifically, assuming that in a multi-motor cooperative control system, three low-frequency signals of speed control, position control and torque control need to be processed simultaneously, their frequencies are 2Hz, 5Hz and 8Hz respectively. The system will first construct three sets of orthogonal modulation basis vectors according to these frequency characteristics. For example, the first set of basis vectors may use cosine modulation with a frequency of 20Hz; the second set uses sine modulation with a frequency of 25Hz; the third set uses orthogonal basis functions with a modulation frequency of 30Hz. This frequency configuration ensures good orthogonality between each set of basis vectors, while maintaining sufficient frequency separation from the original control signals.

[0099] In the mapping process, if it is found that the speed control signal has large fluctuations in the range of 2-3 Hz, the system will adjust the modulation depth of the first group of basis vectors accordingly, reducing the initial setting of 0.8 modulation depth to 0.6, to enhance the anti-interference ability of the system. Similarly, when the position control signal has an interference component of 5.5 Hz, the system will automatically adjust the bandpass characteristics of the second group of basis vectors, narrowing the bandwidth from the original 2 Hz to 1.5 Hz, to better filter out adjacent frequency interference.

[0100] S4: According to the time slot allocation scheme and the orthogonal modulation basis vector, the signal transmission timing of the control board is reconstructed, so that the control signals of the high-frequency signal group and the low-frequency signal group do not interfere with each other.

[0101] In the reconstruction of the signal transmission timing of the control board, first, the high-frequency signal group is arranged according to the time slot allocation scheme; after determining the time slot requirement of the high-frequency signal, the number and position of the time slots required by each high-frequency signal are calculated and fixed at a specific position on the time axis; if a high-frequency signal requires strict periodic sampling, its time slot allocation must ensure equal interval to ensure the uniformity of sampling; when multiple high-frequency signals request the same time slot, the time slot ownership is determined based on signal priority;

[0102] After completing the time slot allocation of the high-frequency signal, all remaining available time slots are counted; after obtaining the idle time slot distribution, the transmission characteristics of the low-frequency signal group under the orthogonal modulation basis vector are calculated; for each low-frequency signal, the minimum transmission bandwidth required is determined according to its projection on the orthogonal basis vector; if multiple low-frequency signals can share the same time slot after orthogonal modulation, these signals are combined into the same time slot group; when the low-frequency signal group has a transmission request, the appropriate idle time slot is selected for transmission without affecting the transmission of high-frequency signals;

[0103] In signal isolation, the focus is on the boundary processing of high-frequency signal time slots and low-frequency signal time slots; when the time slots of high-frequency signals and low-frequency signals are adjacent, a guard interval is inserted between them; for the low-frequency signals modulated orthogonally, it is ensured that the modulation process will not interfere with the adjacent high-frequency signal time slots; if crosstalk is detected, the length of the guard interval is increased or the modulation parameters of the low-frequency signal are adjusted; when the protection requirement cannot be met, the low-frequency signal group is transferred to other idle time slots.

[0104] In establishing the transmission timing table, the time slot position of the high-frequency signal is taken as the reference point; after the reference point is determined, the low-frequency signal group that is quadrature modulated is reasonably arranged around it; for the low-frequency signal group, signal multiplexing is carried out based on the characteristics of the quadrature modulation basis vector; if the transmission demand of the low-frequency signal group changes, dynamic adjustment is carried out without affecting the time slot of the high-frequency signal; when the system load is heavy, the time slot demand of the high-frequency signal is preferentially guaranteed, and the characteristics of the quadrature modulation basis vector are used to improve the transmission efficiency of the low-frequency signal.

[0105] In more detail, after the time slot reference point of the high-frequency signal is determined, the low-frequency signal group is first classified and counted, and the bandwidth demand and modulation characteristics of each low-frequency signal are recorded; after obtaining the characteristics of the low-frequency signal, signals with similar bandwidth demand are classified into the same group, and the mapping relationship of each group of signals on the quadrature modulation basis vector is calculated; if the modulation characteristics of a group of signals are similar, they are arranged for transmission within the same time interval.

[0106] When allocating the transmission interval of the low-frequency signal, the idle area far from the time slot of the high-frequency signal is preferentially selected; after a suitable idle area is found, the number of quadrature modulated signals that can be accommodated in the area is calculated; the low-frequency signals in the selected area are quadrature modulated and encoded to maintain good orthogonality between signals; if the signal capacity of a certain area is close to saturation, a new idle area is enabled for allocation; when adjacent areas have been occupied, the spectral utilization efficiency is improved by adjusting the quadrature modulation parameters. When multiple low-frequency signals are arranged in the same time interval, the orthogonality characteristics of the quadrature modulation basis vector are used to ensure that the signals do not interfere with each other; if the orthogonality between the signals is found to be below the threshold, the modulation parameters of the signals are adjusted or the transmission interval is re-allocated; if the adjustment still cannot meet the quadrature requirement, part of the signals are transferred to other idle areas.

[0107] It is worth noting that although the above description outlines the general process of reconstructing the control board signal transmission timing, the specific implementation details may vary depending on different control systems and their application scenarios. For example, in the control system of an industrial robot, the high-frequency signal group may include motor position feedback signals (sampling frequency 2kHz), speed feedback signals (sampling frequency 1kHz), and other signals that have strict timing requirements. These signals will be preferentially allocated to fixed time slots, such as position feedback signals occupying a time slot every 0.5ms and speed feedback signals occupying a time slot every 1ms. The low-frequency signal group may include temperature monitoring signals (sampling frequency 10Hz), current detection signals (sampling frequency 100Hz), and other relatively non-urgent control signals, which can be multiplexed through the quadrature modulation basis vector and transmitted in the same time slot.

[0108] Overall, although the above description outlines the general process of improving the anti-interference ability of the control board, the specific implementation ideas may vary depending on different control signals and application scenarios, for example, in the case of a four-axis linkage numerical control machine tool, the control board needs to control four servo motors at the same time. In the traditional scheme, the control signals of the four motors (including position, speed, and current feedback signals for each motor) often interfere with each other during transmission, resulting in a decrease in control accuracy. For example, when the X-axis motor accelerates, the high-frequency interference generated will affect the position feedback signal of the Y-axis, causing the positioning accuracy of the Y-axis to decrease from ±0.01 mm to ±0.05 mm. After adopting the present scheme, through the time slot allocation scheme, the system strictly allocates the high-frequency control signals of the four motors to different time slots. This staggered arrangement in time ensures that the position feedback signals of each axis do not interfere with each other, and even in the case of simultaneous movement of the four axes, the positioning accuracy of each axis can still be maintained within ±0.01 mm. At the same time, a 5 μs protection interval is set between adjacent time slots, further reducing the transient interference during signal switching. For the low-frequency monitoring signals of each axis (such as temperature, load rate, etc.), the orthogonal modulation basis vector is used for encoding after which the time slot resources can be shared. For example: the X-axis temperature signal is modulated to cos(2πt). Even if the four temperature signals are transmitted in the same time slot, the cross-talk between the signals can be controlled to be below -40 dB, ensuring the accuracy of the monitoring data. Not only does this solve the mutual interference between high and low frequency signals, but it also solves the mutual interference between multiple signals of the same type, improving the anti-interference ability of the control board while ensuring its control accuracy.

[0109] In the technical scheme of the present application, by collecting the frequency characteristics of each motor control signal in the control board, Fourier analysis is used to classify the signal spectrum, and the control signals are divided into high-frequency signal groups and low-frequency signal groups. Different interference suppression strategies are adopted for signal groups with different frequency characteristics. By allocating time slots to the high-frequency signal group, the independent occupation of the time slot by the signal is realized, effectively avoiding the superposition of high-frequency interference. At the same time, based on the frequency characteristics of the low-frequency signal group, an orthogonal modulation basis vector is constructed to map the low-frequency signals, ensuring good orthogonality between low-frequency signals and avoiding mutual interference. In addition, by reconstructing the signal transmission timing, the isolation of high and low frequency signals and the resource utilization efficiency are further optimized. Compared with the prior art, the present application can solve the technical problem of control board in which the control precision decreases due to mutual interference of control signals when multiple motors are running at the same time. Not only does it significantly improve the anti-interference ability of the control board in a complex multi-signal environment, but it also ensures the real-time and accuracy of signal transmission, especially suitable for multi-motor control, high-precision industrial automation, and other fields.

[0110] The computer program product of the present application can be a storage medium or a computer program product that stores computer executable instructions. When the computer executable instructions are executed by one or more processors, the one or more processors perform the methods according to the embodiments of the present application.

[0111] The units described in the embodiments of the present application can be implemented by software, or by hardware, or by a combination of software and hardware. The units described can be located in one place or distributed over several places. The name of the units in some cases does not limit the units themselves.

[0112] According to an aspect of the present application, a computer program product or computer program is provided, which includes computer instructions stored in a computer readable storage medium. A processor of a computer device reads the computer instructions from the computer readable storage medium, and the processor executes the computer instructions, so that the computer device performs the method provided in the various optional implementation manners.

[0113] From the above description of the embodiments, those skilled in the art can easily understand that the example embodiments described herein can be implemented by software, or by software in combination with necessary hardware. Therefore, the technical solutions according to the embodiments of the present application can be embodied in the form of a software product. The software product can be stored in a nonvolatile storage medium (which can be a CD-ROM, a USB flash disk, a mobile hard disk, or the like) or a network, and includes a number of instructions to make a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) execute the methods according to the embodiments of the present application.

[0114] Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the application following the general principles thereof and including such departures from the present disclosure as come within known use or custom in the art.

[0115] It should be understood that the application is not limited to the precise construction which has been described above and which shown in the drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application should be limited only by the appended claims.

Claims

1. A method for improving the interference immunity of a control board, characterized in that, The method comprises the following steps: Collecting frequency characteristics of each motor control signal in the control board, performing Fourier analysis on the frequency characteristics to obtain a frequency spectrum, and dividing the control signals into a high-frequency signal group and a low-frequency signal group according to the frequency spectrum; Time slot allocation is performed on the control signals in the high-frequency signal group, the transmission cycle of the high-frequency signal group is divided into N time slots, N is the number of signals in the high-frequency signal group, and each control signal occupies one time slot; Based on the frequency characteristics of the low-frequency signal group, an orthogonal modulation basis vector is constructed, and the control signals in the low-frequency signal group are mapped onto the orthogonal modulation basis vector; According to the time slot allocation and the orthogonal modulation basis vector, the signal transmission timing of the control board is reconstructed, so that the control signals in the high-frequency signal group and the low-frequency signal group do not interfere with each other; The method for constructing the orthogonal modulation basis vector comprises the following steps: Performing spectrum analysis on all control signals in the low-frequency signal group to obtain the bandwidth characteristics and frequency distribution of each signal; An initial orthogonal basis is constructed by using a Schmidt orthogonalization method, and a signal with the maximum spectral energy is selected as a first basis vector; The initial orthogonal basis is optimized, and the direction and amplitude of the basis vector are adjusted by a minimum mean square error criterion; When the basis vector is constructed, the orthogonality between the basis vectors is calculated, and if the orthogonality is lower than a first preset threshold, a correction term is introduced for fine tuning until the orthogonality meets the requirements.

2. The method of claim 1, wherein, According to the signal energy distribution characteristics in the frequency spectrum, a main frequency component is identified by using an adaptive threshold detection algorithm; The detection logic of the adaptive threshold detection algorithm is as follows: The energy values of the frequency components in the frequency spectrum are calculated, and the energy values are arranged in descending order to obtain an energy sequence; When there is an energy aggregation area in the frequency spectrum, a region growing method is used to determine the main frequency bandwidth; When the energy distribution of the frequency spectrum is relatively dispersed, an iterative threshold method is used for main frequency identification; When there are multiple frequency components with similar energy, the energy ratio between the frequency components is calculated, and if the ratio of the maximum energy component to the second largest energy component is less than a first preset value, the frequency components are all identified as main frequency components; When the signal has a frequency drift phenomenon, a time-frequency diagram is obtained by calculating a short-time Fourier transform, the main frequency component is dynamically tracked, and if the frequency drift exceeds a first preset percentage of the center frequency, the main frequency is re-identified; After the main frequency is identified, the energy proportion of the main frequency component is calculated, and the frequency range with an energy proportion exceeding a second preset percentage of the total energy is determined as the final main frequency bandwidth.

3. The method of claim 1, wherein the control board is a control board of a mobile terminal. The time slot allocation comprises the following steps: Priority information of each control signal in the high-frequency signal group is obtained; the priority information includes real-time requirements and control accuracy requirements of the signal; When the real-time requirement of a control signal is higher than a second preset value, the control signal is marked as the highest priority, and a time slot is allocated preferentially; when there are multiple control signals with the same priority, the time slots are grouped according to the bandwidth requirements of the signals, and the signals with similar bandwidth requirements are arranged in adjacent time slots. In the time slot allocation, a dynamic time slot reservation mechanism is adopted; when the signal transmission in a time slot is completed in advance, the time slot multiplexing mechanism is used to allocate the remaining time to the adjacent time slot with data backlog.

4. The method of claim 3, wherein the control board is a control board of a mobile terminal. In the implementation of the dynamic time slot reservation mechanism, a sliding window is established to record the transmission state of each signal. When data overflow occurs in a control signal in the sliding window, the amount of data and the duration of the overflow are recorded. If the number of data overflows exceeds 3 times and the amount of data overflow in a single time exceeds the third preset percentage of the buffer capacity, the time slot reservation program is triggered. The time slot reservation program includes: A standby time slot is reserved after the exclusive time slot of the signal; if the subsequent time slot is occupied, the time slot compression algorithm is used to reorganize the existing time slots, and the duration of all time slots is uniformly compressed by 1 / 10 to free up additional standby time slots; when the reserved time slot is not used for 5 transmission periods, the reserved time slot is automatically recovered; if data overflow still occurs after the signal obtains the reserved time slot, the signal is marked as an abnormal state, and the signal bandwidth reestimation program is started.

5. The method of claim 4, wherein the method further comprises: The actual use of each time slot is detected in real time, and when it is detected that a time slot is completed in advance and the remaining time exceeds the preset time, the time slot multiplexing mechanism is triggered. The time slot allocation also includes a time slot reallocation mechanism. When a control signal does not arrive on time for 3 consecutive transmission periods, the time slot reallocation mechanism is executed. Before performing time slot reallocation, the bandwidth requirements of all active signals are reevaluated; when there are multiple signals requesting time slot reallocation, a reallocation priority queue is established according to the priority and data backlog of the signals; if a signal obtains a reallocated time slot, its original time slot will be temporarily marked as a standby state; when the original signal resumes normal transmission, the original time slot allocation scheme will be restored at the beginning of the next transmission period; if the original signal continues to be abnormal for more than 10 transmission periods, the permanent reallocation program is started to reconstruct the entire time slot allocation scheme.

6. The method of claim 5, wherein the control board is a control board of a mobile terminal. Adjusting the direction and amplitude of the basis vector by the minimum mean square error criterion includes: An error objective function is established, and the mean square error between the original signal and the basis vector reconstruction signal is taken as the optimization objective; The weight coefficient of each basis vector is calculated, and if the weight coefficient of a basis vector is less than a second preset threshold, the basis vector is marked as an optimization object; The direction and amplitude of the optimization object are adjusted.

7. The method of claim 6, wherein the method further comprises: The adjustment direction includes: The angle between each basis vector and the error vector is calculated; when the angle is greater than a preset threshold, the adjustment direction is determined according to the error size; each time the basis vector is adjusted, the direction of the basis vector is offset towards the error vector, and the offset amount is determined by the error size and a fixed adjustment coefficient; After each adjustment, it is checked whether the adjusted basis vector meets the following constraints: The orthogonality between the basis vectors is not less than a third preset threshold, the deviation angle from the original direction is not more than 45 degrees, and the reconstruction error of the adjusted signal is less than the error before adjustment; If any constraint is violated, the adjustment amount needs to be limited, and the specific limiting method is: When the orthogonality does not meet the requirements, the adjustment amount is projected along the direction of keeping orthogonality; when the deviation angle is too large, the adjustment amount is limited in the maximum allowable range; when the reconstruction error increases, the adjustment amount is proportionally reduced.

8. A system for improving the immunity of a control board, characterized by, The method comprises the steps of: The acquisition module is configured to acquire frequency characteristics of motor control signals in the control board. The frequency spectrum division module is configured to perform Fourier analysis on the frequency characteristics to obtain a frequency spectrum graph, and divide the control signals into a high-frequency signal group and a low-frequency signal group according to the frequency spectrum graph. The time slot allocation module is configured to allocate time slots to the control signals in the high-frequency signal group, divide the transmission period of the high-frequency signal group into N time slots, and each control signal occupies one time slot. The mapping module is configured to construct an orthogonal modulation basis vector based on the frequency characteristics of the low-frequency signal group, and map the control signals of the low-frequency signal group to the orthogonal modulation basis vector. The signal reconstruction module is configured to reconstruct the signal transmission timing of the control board based on the time slot allocation and the orthogonal modulation basis vector, so that the control signals of the high-frequency signal group and the low-frequency signal group do not interfere with each other. The construction of the orthogonal modulation basis vector comprises: Performing spectrum analysis on all control signals in the low-frequency signal group to obtain the bandwidth characteristics and frequency distribution of each signal. An initial orthogonal basis is constructed by using the Schmidt orthogonalization method, and a signal with the maximum spectral energy is selected as the first basis vector. The initial orthogonal basis is optimized to adjust the direction and amplitude of the basis vector by the least mean square error criterion. When the basis vector is constructed, the orthogonality between the basis vectors is calculated, and if the orthogonality is lower than a first preset threshold, a correction term is introduced for fine tuning until the orthogonality meets the requirements.

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