A grinding wheel wear amount adaptive compensation control method based on billet dressing grinding

Abstract

This invention belongs to the field of grinding wheel dredging control technology, specifically disclosing an adaptive compensation control method for grinding wheel wear based on billet grinding. The method determines the segment of the oscillating head by monitoring the position feedback signal of the oscillating actuator. During the uniform speed advance segment, torque current and pressure values ​​are collected as valid data. Data collection is paused during the reversing segment, effectively separating the instantaneous fluctuations caused by the reversing impact from the actual grinding state changes. This ensures that the data frames used in subsequent judgments all originate from the stable cutting segment. By synchronously collecting torque current and pressure values ​​during the stable cutting segment and comparing them, grinding characterization values ​​are obtained. The deviation direction and magnitude of these values ​​from the zero-point reference value under no-load conditions are used to determine the working condition, thus solving the problem that a single current signal cannot distinguish grinding resistance changes caused by different factors. Based on this, differentiated compensation is performed according to the judgment results, achieving adaptive compensation for different working conditions.

Description

Technical Field

[0001] This invention belongs to the field of grinding wheel regrinding control technology, and specifically discloses an adaptive compensation control method for grinding wheel wear based on steel billet grinding. Background Technology

[0002] Steel billets are semi-finished products obtained after molten steel is cast. During the casting and heating processes, defects such as cracks and scale inevitably form on their surface. These defects will further extend and expand during subsequent rolling, leading to a significant reduction in yield. Therefore, grinding the surface of the steel billet before rolling is a crucial step in steel production.

[0003] Steel billet regrinding usually involves grinding the surface of the steel billet with a grinding wheel. During the regrinding process, the abrasive grains in the working layer of the grinding wheel continuously wear and break under the action of high-speed friction and high temperature, which leads to a decrease in the grinding ability of the grinding wheel.

[0004] To address the impact of grinding wheel wear on grinding quality, existing technologies include solutions that detect changes in the current of the spindle drive to sense the wear state of the grinding wheel. The principle is that when the grinding wheel becomes dull, the grinding resistance increases, and the spindle motor needs to output more torque to overcome the resistance, thus increasing the drive current accordingly. When the current reaches a set threshold, a compensation signal is output.

[0005] However, the above solution overlooks the fact that both dulling of the grinding wheel abrasive grains and the presence of hard spots in the billet will increase the torque current of the spindle drive. This signal aliasing can lead to misjudgment of the compensation action: at hard spots, it may be misjudged as grinding wheel wear and depth compensation may be performed, forcing the grinding wheel to overfeed, causing abnormal breakage of the grinding wheel or even the ejection of fragments; at soft spots, it may fail to identify the abnormal decrease in grinding resistance, resulting in insufficient compensation, causing the defect layer to flow into the next rolling process without being completely removed, ultimately causing the finished product to be scrapped.

[0006] Furthermore, during the steel billet grinding process, the grinding wheel head oscillates back and forth. When it reaches the edge and reverses direction, the mechanical inertia will cause an impact, resulting in a violent fluctuation in the torque current. However, the existing solution only focuses on whether the signal value reaches the limit, without distinguishing the segment where the oscillating head is located when the signal is collected. This results in the signals of the uniform speed segment and the reversing segment being collected and processed equally. It is impossible to effectively distinguish the instantaneous fluctuation of the reversing impact from the actual changes in the grinding state. This easily leads to the misjudgment of transient interference as changes in the working condition, further exacerbating the risk of misjudgment. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the present invention provides an adaptive compensation control method for grinding wheel wear based on steel billet grinding, which is used to solve the problems existing in the prior art.

[0008] The objective of this invention can be achieved through the following technical solution: an adaptive compensation control method for grinding wheel wear based on billet grinding, comprising the following steps: in this grinding pass, the swing head section is determined by monitoring the position feedback signal of the swing drive, and the torque current value of the spindle drive and the pressure value of the downward pressure cylinder are collected as valid data in the uniform speed forward section.

[0009] The grinding characterization value is obtained by comparing the torque current value with the pressure value. The grinding characterization value is compared with the zero-point reference value. The current working condition is determined as hard point, soft point, or true wear of the grinding wheel based on the deviation direction and change range. The zero-point reference value is determined based on the torque current no-load value read by the grinding wheel under no-load condition before the grinding starts.

[0010] When a hard point is identified, the set pressure of the down-pressing cylinder is reduced and the feed direction position is locked.

[0011] When a soft mass is identified, the operating frequency of the oscillating driver is reduced and the frequency reduction trigger is recorded.

[0012] When the grinding wheel is determined to be truly worn, the feed increment is added to the feed setpoint at each reversal.

[0013] When the grinding cycle reaches the end, the cumulative number of frequency reduction triggers is counted. If the limit is exceeded, the dwell time at the commutation edge is increased in the next cycle.

[0014] Repeat the above steps until the grinding is complete.

[0015] Combining all the above technical solutions, the positive effects of this invention are as follows: 1. This invention determines the segment where the swing head is located by monitoring the position feedback signal of the swing drive. In the uniform forward segment, the torque current value and pressure value are collected as valid data. The collection is paused in the reversing segment, thereby effectively separating the instantaneous fluctuations caused by the reversing impact from the actual grinding state changes, eliminating the interference components introduced by mechanical inertia, and ensuring that the data frames participating in the subsequent judgment all originate from the stable cutting segment, effectively reducing the misleading effect of transient interference on state judgment.

[0016] 2. This invention obtains grinding characterization values ​​by synchronously collecting torque current values ​​and pressure values ​​in the stable cutting section and comparing them. It uses the deviation direction and change range of these values ​​from the zero-point reference value under no-load conditions to determine the working condition, thereby solving the problem that a single current signal cannot distinguish the changes in grinding resistance caused by different reasons. Based on this, differentiated compensation is performed according to the judgment results to achieve adaptive and accurate compensation for different working conditions. Attached Figure Description

[0017] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0018] Figure 1 This is a diagram illustrating the implementation steps of the method of the present invention;

[0019] Figure 2 This is a flowchart illustrating the implementation process of collecting the torque current value of the spindle drive and the pressure value of the downward pressure cylinder as valid data in this invention.

[0020] Figure 3 This is a flowchart illustrating the implementation of step S4 in this invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention proposes an adaptive compensation control method for grinding wheel wear based on billet grinding, such as... Figure 1 As shown, the process includes the following steps: S1. During this grinding cycle, the swing head section is determined by monitoring the position feedback signal of the swing drive. In the uniform forward section, the torque current value of the spindle drive and the pressure value of the downward pressure cylinder are collected as valid data.

[0023] During the billet grinding process, given that the grinding coverage of the grinding wheel in the width direction of the billet is limited, a single grinding stroke cannot cover the entire width of the billet. Therefore, it is necessary to cover the billet width step by step, that is, to perform the grinding operation according to the number of passes. Each pass corresponds to one complete reciprocating swing stroke of the grinding wheel frame.

[0024] Within a complete pass, the grinding wheel head needs to move from one end of the billet width direction to the other end. When it reaches the edge of the billet, it performs a reversal action. During the mechanical reversal, the motion inertia will impact the spindle system, causing the torque current to fluctuate violently. This fluctuation is not a true reflection of the state of the grinding interface. If it is mixed into the collected data, it will directly lead to deviations in the subsequent state judgment based on the torque current.

[0025] Therefore, this embodiment determines the current segment of the oscillating head by monitoring the position feedback signal of the oscillating drive. When the oscillating head is in the uniform forward movement segment, the mechanical movement is stable, and the torque current can accurately reflect the cutting state of the grinding interface; data acquisition is then performed at this time. When the oscillating head reaches the edge of the billet and enters the reversing segment, the torque current fluctuations generated in this segment are only transient disturbances caused by mechanical inertia and cannot represent the true state of the grinding interface; therefore, data acquisition is paused. This segment determination largely ensures that the data subsequently used in the judgment calculation all originate from a stable and realistic cutting state.

[0026] In one specific embodiment, the determination of the swing head section is carried out according to the following process: The swing drive is an actuator that drives the grinding wheel frame to reciprocate along the width direction of the billet. The rotation angle of its output shaft corresponds to the displacement of the grinding wheel frame. In order to realize the real-time sensing of the swing head position, a position encoder is installed on the output shaft of the swing drive. The encoder rotates synchronously with the output shaft. During the rotation, the grating or magnetic grating inside the encoder generates relative motion with the detection element, thereby outputting a series of pulse signals. The number of pulse signals is proportional to the angle through which the output shaft rotates. Therefore, the pulse signal can be used as a feedback signal to characterize the real-time position of the swing head.

[0027] After receiving the pulse signal output by the position encoder, the control system correlates the accumulated pulse signal with the rotation angle of the output shaft of the oscillating drive, i.e., it counts the pulses. Based on the total number of pulses per encoder revolution and the lead screw, the accumulated pulse is converted into the real-time position value of the grinding wheel head in the width direction of the billet. At the same time, the left and right limit positions of the oscillation stroke of the grinding wheel head in the width direction of the billet (i.e., the physical boundaries where the grinding wheel head can no longer move forward) are used as calibration positions. The real-time position values ​​read at these positions are respectively calibrated as the left and right boundary values, which serve as boundary references for subsequent determination of the segment where the oscillating head is located.

[0028] After the boundary calibration is completed, the control system will continuously compare the real-time position value with the left and right boundary values. When the real-time position value is simultaneously between the left and right boundary values ​​and the difference between the real-time position value and the left and right boundary values ​​is greater than the edge threshold, it indicates that the oscillating head is in the middle stroke segment far from the left and right limit positions, the mechanical movement is stable, and it is determined that the oscillating head is currently in the uniform speed forward segment.

[0029] When the difference between the real-time position value and the left boundary value is less than or equal to the edge threshold, or the difference between the real-time position value and the right boundary value is less than or equal to the edge threshold, it indicates that the swing head has moved to the area close to the edge of the billet and is about to enter or is performing a reversing action. It is determined that the swing head is currently in the reversing segment.

[0030] Among them, the edge threshold is a preset boundary judgment parameter to distinguish the middle section of normal cutting from the reversing section near the edge. The threshold is set as follows: During the equipment debugging stage, the swing drive is run at the normal grinding speed and its rotation speed is monitored in real time. When the rotation speed drops from the rated speed to 95% of the rated speed, it is determined that the moment when the speed begins to drop. The grinding wheel frame position value corresponding to this moment is recorded, and the travel distance from this position point to the limit position is used as the edge threshold.

[0031] Perform the operation once on each side of the billet width direction, repeating it no less than 5 times on each side. Calculate the arithmetic mean of the 5 recorded values ​​on each side, and use them as the left edge threshold and right edge threshold.

[0032] After determining the segment and the timing of data acquisition, it is necessary to further define the acquisition target. While a single torque current signal can reflect changes in resistance during grinding, its amplitude is also affected by the magnitude of the downward pressure. That is, the same grinding interface state will exhibit different torque current values ​​under different downward pressures. If the absolute value of the torque current is directly used as the basis for state judgment, it is impossible to distinguish whether the current change originates from a change in interface state or fluctuations in downward pressure. Therefore, this embodiment combines the torque current value of the spindle drive with the pressure value of the downward pressure cylinder. By comparing the two, a grinding characterization value under unit pressure is constructed, representing the magnitude of cutting resistance under unit pressure, thereby eliminating the interference of downward pressure fluctuations on signal interpretation.

[0033] See Figure 2 The specific data acquisition process is as follows: When the uniform speed forward section is determined, the pressure value of the downward pressing cylinder is continuously monitored. When the pressure is stable and not zero, a sampling trigger signal is sent to the spindle drive and pressure transmitter. The torque current value and pressure value are read and combined into a valid data. This is because the construction of grinding characterization values ​​depends on the ratio calculation of torque current and pressure. If the pressure is zero, it indicates that the grinding wheel has not formed effective contact with the steel billet, and the ratio has no physical meaning. In addition, in the initial stage when the grinding wheel head downward pressing cylinder starts to move, the pressure value usually shows a transition process of rapid rise from zero accompanied by oscillation. During this stage, the pressure has not yet entered a stable state, and the data collected at this time does not have the conditions to construct reliable grinding characterization values.

[0034] In a preferred embodiment, the pressure stability is determined as follows: the pressure value read at the current sampling time is subtracted from the pressure value read at the previous sampling time to obtain the pressure change at the current time. If the pressure change at three consecutive adjacent sampling times does not exceed the stable change amount, the current pressure is determined to have entered a stable state. For example, the stable pressure change amount can be set to 1% of the rated pressure.

[0035] When the segment is determined to be a reversal segment or the pressure value is zero, the data is not representative, and data acquisition is paused. Data acquisition will resume after the next uniform speed advance segment and the pressure value returns to a non-zero state.

[0036] S2. Compare the torque current value with the pressure value to obtain the grinding characterization value. Compare the grinding characterization value with the zero-point reference value. Determine whether the current working condition is hard point, soft point, or true wear of the grinding wheel based on the direction of deviation and the magnitude of change. The zero-point reference value is determined based on the torque current no-load value read by the grinding wheel under no-load condition before the grinding begins.

[0037] After obtaining the torque current value and pressure value synchronously collected in the stable cutting section through step S1, the two can be compared to construct the grinding characterization value, thereby further judging the current grinding condition.

[0038] However, the grinding performance value at a single moment cannot determine whether its amplitude is normal or abnormal. Therefore, a reference datum is needed to determine the zero point of the grinding performance value, that is, the reference value under no cutting load. To this end, the present invention proposes a zero-point reference value.

[0039] As one method for determining the zero-point reference value that can be implemented by the present invention, before the first grinding begins and after each grinding cycle, the grinding wheel is in an unloaded rotating state and the pressure cylinder is completely depressurized. At this time, the pressure value is zero, and the torque current unload value of the spindle drive is read in this state.

[0040] The no-load value of torque current is used as the equivalent reference value of grinding characterization under zero pressure conditions, and is recorded as the zero-point reference value of the current grinding pass. Since the no-load state represents the benchmark working condition without cutting load, the torque current only characterizes the system idling loss. The difference between the grinding characterization value collected in the subsequent actual cutting process and this zero-point reference value is the deviation of the current grinding state from the no-load benchmark working condition. The direction and magnitude of this deviation together constitute the basis for judging the working condition.

[0041] It should be noted that the zero-point reference value and the grinding characterization value are different values ​​of the same physical quantity under no-load and loaded conditions: under no-load conditions, the pressure is zero, and the grinding characterization value is equivalent to the no-load torque current value, i.e., the zero-point reference value; under loaded conditions, the grinding characterization value is the cutting resistance under unit pressure. In actual cutting, when the grinding wheel and the steel billet form effective contact, the grinding characterization value is significantly greater than the zero-point reference value. Therefore, a positive deviation indicates the presence of an effective cutting load, while a deviation of zero or negative indicates that the grinding state is close to no-load or below normal levels, corresponding to abnormal working conditions such as soft spots or wear.

[0042] Furthermore, the working condition judgment process is as follows: Subtract the zero-point reference value from the grinding characterization value of each valid data to obtain the deviation of the data. The deviation reflects the degree of deviation of the current grinding state from the no-load reference working condition. A positive deviation indicates that the current grinding resistance is higher than the reference state, and a negative deviation indicates that the current grinding resistance is lower than the reference state.

[0043] Subtracting the deviation of the previous valid data from the deviation of the current valid data yields the magnitude of the deviation change between adjacent data. The magnitude of the deviation change reflects the rate of change of the grinding interface state. The larger the absolute value, the more drastic the change in the interface state. When the absolute value is close to zero, it indicates that the interface state tends to be stable.

[0044] a) If the difference between the grinding characterization values ​​of adjacent valid data is positive and the difference exceeds the mutation threshold, it indicates that the grinding resistance has increased sharply in a short period of time, and is recorded as a positive mutation event. After this event, if the deviation of multiple consecutive valid data (e.g., 5) is positive and the absolute value of the deviation change is close to zero, it indicates that the grinding resistance has stabilized at a state higher than the reference after the sharp increase.

[0045] From a physical perspective, when a grinding wheel encounters a localized hard point, the hard point exerts intense cutting resistance on the abrasive grains, causing the torque current to surge instantaneously. After the hard point passes, the system reaches a new stable state at this higher resistance level, at which point it is determined that a hard point has been encountered.

[0046] b) If the difference between the grinding characterization values ​​of adjacent valid data is negative and the absolute value of the difference exceeds the mutation threshold, it indicates that the grinding resistance has decreased sharply in a short period of time, and is recorded as a negative mutation event. After this event, if the deviation of multiple consecutive valid data is negative and the absolute value of the deviation change is close to zero, it indicates that the grinding resistance has stabilized at a state below the baseline after the sharp decrease.

[0047] From a physical perspective, when a grinding wheel encounters a local soft point, the cutting resistance of the soft area to the abrasive grains decreases sharply, and the torque current drops instantly. After passing the soft point, the system reaches a new stable state at this lower resistance level, at which point it is determined that a soft point has been encountered.

[0048] The absolute value of the deviation change amplitude mentioned above is close to zero, which means that the deviation of adjacent data is almost the same. For example, the difference between adjacent deviations can not exceed 2% of the current grinding characterization value as a criterion for being close to zero.

[0049] c) If no positive or negative mutation event is triggered, and the deviation of multiple consecutive valid data is negative, and the average absolute value of the deviation of the second half of the data arranged in the order of collection time is greater than the average absolute value of the deviation of the first half of the data, it indicates that the grinding resistance has not changed abruptly, but the grinding resistance continues to be lower than the reference and shows a further downward trend. At this time, it is determined to be true wear of the grinding wheel.

[0050] It should be noted that grinding wheel wear involves two simultaneous physical effects: abrasive passivation and radial dimension reduction. Abrasive passivation increases grinding resistance, while radial dimension reduction leads to a decrease in the actual depth of cut, resulting in lower material removal rate and reduced torque current. These two effects coexist and act in opposite directions during regrinding. In this embodiment, a negative deviation indicates that the decrease in depth of cut is dominant after the combined effect of the two factors. In other words, the deviation captures the overall result of the reduction in the grinding wheel's cutting ability. Therefore, a negative deviation with a gradually increasing absolute value corresponds to a gradual process of continuous reduction in the grinding wheel's radial dimension and cutting ability, which is a form of wear-related degradation.

[0051] In the embodiments applied to the above scheme, the mutation threshold is a boundary parameter used to distinguish between normal process fluctuations and sudden changes in operating conditions. It is pre-calibrated during the equipment commissioning stage. The calibration method is as follows: during the equipment commissioning stage, the equipment is run with the set grinding process parameters. A standard steel billet confirmed to have no internal defects by flaw detection is used. The difference between adjacent grinding characterization values ​​of no less than 100 sets of valid data is continuously collected. The collected differences are arranged in ascending order of amplitude, and the difference corresponding to the 95th percentile is taken as the mutation threshold.

[0052] The first and second halves of the data refer to the first and second halves of the data after multiple consecutive valid data are arranged in the order of collection time. If the total number of data frames is odd, the middle frame is discarded. By comparing whether the average value of the absolute value of the deviation of the second half of the data is greater than or less than the average value of the first half of the data, it is determined whether the absolute value of the deviation shows an overall increase or decrease in the time series. This method allows fluctuations in individual data and does not require each data to strictly increase or decrease.

[0053] It should be noted that in this embodiment, different data are used for mutation detection and post-mutation stability confirmation. This is because mutation detection uses the difference in grinding characterization values ​​of adjacent valid data, and this judgment is independent of the zero-point reference value, only needing to confirm whether a drastic change has occurred. Post-mutation stability confirmation uses the deviation change amplitude because the deviation has been characterized by the current state relative to the reference by subtracting the zero-point reference value. Its change amplitude is close to zero, indicating that the current position has tended to be constant. Since the zero-point reference value remains unchanged within the same pass, the two are numerically equivalent and there is no calculation deviation. The deviation change amplitude and the deviation share the same reference system, so that the position judgment and stability judgment in the judgment logic are consistent on the reference reference.

[0054] S3. After determining the working conditions, implement targeted differentiated compensation.

[0055] 1) When a hard point is identified, reduce the set pressure of the down-pressing cylinder and lock the feed direction position.

[0056] The characteristic of hard point conditions is the appearance of localized hard inclusions at the grinding interface, resulting in a sudden and significant increase in grinding resistance. If the original downward pressure and feed depth are maintained at this point, intense compression occurs between the grinding wheel and the hard point, easily causing large-scale breakage or even complete fracture of the grinding wheel abrasive grains. Therefore, the compensation action should involve instantaneous unloading and maintaining the feed depth. This reduces the downward pressure to decrease grinding resistance and locks the current feed depth to prevent the grinding wheel from continuing to cut into the hard point.

[0057] The specific compensation process is as follows: After obtaining the hard point determination signal, an unloading command is first output to the pressure control valve of the hydraulic system, so that the working pressure of the pressing cylinder is reduced from the current set value by a preset pressure step, so as to reduce the contact pressure between the grinding wheel and the hard point. The pressure step is a fixed adjustment step size preset in advance according to the response resolution of the hydraulic proportional valve during the equipment commissioning stage. The physical meaning of the response resolution is the minimum pressure change in a single adjustment, which can be set as an integer multiple of the response resolution, for example, 0.1MPa to 0.5MPa.

[0058] At the same time, a position lock signal is output to the feed drive system to keep the displacement setpoint in the feed direction constant and prevent the grinding wheel from continuing to feed beyond the current cutting depth. The purpose of this operation is to prevent the grinding wheel from aggravating the cutting resistance in the hard point area due to continuous feeding and to avoid the grinding wheel from being subjected to excessive mechanical impact.

[0059] Maintain the output status of the unloading command and position lock signal, and continuously acquire the deviation of each valid data. If the deviation is still positive, it means that the current unloading amount is not enough to reduce the grinding resistance and the hard point is still generating impact. Then, continue to reduce the pressure by one step based on the current pressure and perform a new round of deviation judgment. Adjust it in this way until the deviation of multiple consecutive adjacent data is no longer positive, indicating that the hard point has been removed by grinding and the grinding resistance has returned to the reference or below the reference state. At this time, stop reducing the pressure, cancel the unloading command and position lock signal, restore the working pressure of the pressure cylinder to the set value before adjustment, and restore the displacement control in the feed direction.

[0060] If the pressure has been reduced to the minimum working pressure allowed by the hydraulic system, and the deviation still cannot be changed from positive to negative, it is determined that the hard point is extremely hard and exceeds the normal grinding capacity of the grinding wheel. The current grinding pass is terminated and an alarm signal is output to prompt the operator to check the surface condition of the billet.

[0061] 2) When a soft mass is identified, reduce the operating frequency of the oscillating driver and record the frequency reduction trigger.

[0062] The essential characteristic of the soft-point grinding condition is the appearance of localized soft regions at the grinding interface, resulting in a sudden and significant decrease in grinding resistance. If the original oscillation speed is maintained at this point, the grinding wheel's dwell time in the soft-point region will be too short, leading to insufficient grinding passes per unit area and potentially incomplete removal of the defect layer in the soft-point region. Therefore, the compensating action should be to reduce the grinding speed and extend the grinding process, thereby increasing the grinding wheel's dwell time in the soft-point region by decreasing the oscillation speed.

[0063] The specific compensation process is as follows: After obtaining the soft point judgment signal, the frequency reduction command is first output to the swing driver, so that the operating frequency of the swing driver is reduced from the current set value by a preset frequency step, so that the lateral swing speed of the grinding wheel frame in the soft point area is slowed down. The frequency step is a fixed adjustment step size preset in advance according to the speed adjustment resolution of the swing driver during the equipment debugging stage. The physical meaning of the speed adjustment resolution is the minimum frequency change in a single adjustment, which can be taken as an integer multiple of the speed adjustment resolution, for example, 0.5Hz to 2Hz.

[0064] Simultaneously, the triggering event of this frequency adjustment command is recorded in the cumulative counter as a frequency reduction trigger record. This count, by statistically analyzing the total number of frequency reduction triggers within a single pass, can quantitatively assess the distribution range and frequency of soft particles in this pass, providing a basis for decision-making regarding whether to increase edge dwell time in subsequent passes.

[0065] Maintain the output state of the frequency adjustment command and continuously acquire the deviation of each valid data. If the deviation is still negative, it means that the current speed reduction is not enough to allow the grinding wheel to obtain sufficient grinding dwell time in the soft spot area, and the soft spot has not been fully ground. Then, continue to reduce the frequency by one step based on the current frequency and perform a new round of deviation judgment. Adjust in this way until the deviation of multiple consecutive adjacent data is no longer negative, indicating that the soft spot has been ground away and the grinding resistance has returned to or exceeded the reference state. At this time, stop reducing the frequency, cancel the frequency adjustment command, and raise the operating frequency of the oscillating drive back to the set value before adjustment.

[0066] If the operating frequency has been reduced to the minimum operating frequency allowed by the oscillating drive, and the deviation cannot be changed from negative to non-negative, it is determined that the soft spot area is too large or the material is too soft, exceeding the normal grinding capacity of the grinding wheel. The current grinding pass is terminated and an alarm signal is output to prompt the operator to check the surface condition of the billet.

[0067] 3) When it is determined that the grinding wheel is truly worn, the feed increment is added to the feed setpoint at each reversal.

[0068] The characteristics of true wear of grinding wheels are continuous wear and passivation of the abrasive grains in the working layer of the grinding wheel, and a gradual reduction in the radial dimension of the grinding wheel, resulting in a continuous decrease in the effective grinding depth. If no intervention is taken, even if the downward pressure remains unchanged, the actual depth of the grinding wheel into the steel billet will gradually decrease with wear, and the amount of material removed by grinding will decrease with each pass. Therefore, the compensation action should be incremental, gradually increasing the feed depth at the moment of reversal to compensate for the cutting loss caused by the reduction in the grinding wheel diameter. Each increment should only be a small increment, distributing the total compensation amount gradually over multiple reversals, thereby avoiding the impact of a large feed at once on the grinding system.

[0069] The specific compensation process is as follows: After obtaining the true wear judgment signal of the grinding wheel, at the beginning of each swing of the grinding wheel frame to the edge of the billet and entering the reversing section, a feed increment command is superimposed on the feed drive system.

[0070] The feed increment command is triggered once at the start of each reversal. At the moment of reversal, the speed of the grinding wheel head is zero, and the impact of the superimposed feed increment on the mechanical system is minimal. After the head swings away from the reversal section and enters the uniform speed forward section, the execution of the superimposed command stops, and it will be triggered again at the start of the next reversal.

[0071] In the above operation, the magnitude of the feed increment is determined by the current cumulative wear of the grinding wheel. The cumulative wear is characterized by the ratio of the zero-point reference values ​​of adjacent passes. This is because the diameter of the grinding wheel decreases after wear, and the no-load torque current value during no-load rotation decreases accordingly. Therefore, the zero-point reference value gradually decreases as wear intensifies.

[0072] The specific determination method is as follows: First, divide the zero-point reference value of the previous pass by the zero-point reference value of the current pass. The resulting quotient is the wear multiple. The more severe the wear of the grinding wheel, the smaller the zero-point reference value of the current pass, and the larger the quotient.

[0073] Secondly, the magnitude of the feed increment is equal to the unit feed increment multiplied by the wear factor.

[0074] For example, when the zero-point reference value of the current pass drops to half of that of the previous pass, that is, when the zero-point reference value of the previous pass is twice the zero-point reference value of the current pass, the wear factor is 2, and the magnitude of the feed increment is 2 units of feed increment.

[0075] The unit feed increment can be a fixed parameter pre-calibrated according to the grinding process requirements during the equipment commissioning phase. For example, the calibration is performed during the equipment commissioning phase. A new grinding wheel is installed, and a grinding cycle is performed under the set grinding process parameters. The change in the grinding wheel diameter before and after grinding is measured, and this change is taken as the actual wear amount of that cycle. The actual wear amount is divided by the total number of reversals performed in that cycle to obtain the average wear amount corresponding to a single reversal, which is taken as the unit feed increment. This calibration is performed once when each new grinding wheel is used for the first time, and the calibration value is used for subsequent cycles of the same grinding wheel until the grinding wheel is replaced.

[0076] It should be added that when a compensation action is being executed and has not yet exited, even if a judgment signal for another working condition is detected, a new compensation action will not be triggered. The working condition will be re-judged based on subsequent data after the current compensation action exits.

[0077] S4. When the grinding reaches the end of this pass, the cumulative number of frequency reduction triggers is counted. If the limit is exceeded, the dwell time at the commutation edge is increased in the next pass.

[0078] After this grinding pass is completed, in order to determine the edge dwell strategy for the next pass, it is also necessary to evaluate the overall situation of frequency reduction triggering in this pass, such as... Figure 3 As shown, the specific steps are as follows: When the grinding of this pass reaches the end of the billet, the current value of the cumulative counter is read to obtain the total number of frequency reduction triggers for this pass. This number directly reflects the distribution range and frequency of soft points in this pass. The higher the number, the wider the distribution of soft point areas and the denser the occurrence.

[0079] When the total number of frequency reduction triggers exceeds the tolerance value for the number of frequency reductions, it indicates that the distribution range of soft spots in this pass is too wide. Relying solely on the speed reduction grinding in this pass may result in blind spots that are not completely cleared. Therefore, the oscillation control parameters are adjusted before the start of the next pass to extend the reversal pause time of the oscillating head at the left and right boundaries of the billet width direction.

[0080] For the above operations, the delay is implemented by modifying the delay parameter register in the commutation logic of the swing driver to increase the waiting time before the swing head starts reversing after reaching the limit position.

[0081] With the increased delay, the actual grinding length of the grinding wheel in the edge area of ​​the next pass increases, thus forming more grinding overlap with the edge area of ​​the previous pass. This allows for secondary covering grinding of any remaining defect layer in the soft spot area of ​​the previous pass, eliminating blind spots caused by insufficient processing in a single pass.

[0082] If the total number of frequency reduction triggers is less than or equal to the tolerance value for the number of frequency reductions, it indicates that the soft spot distribution range of this pass is within a controllable range and will not change the dwell delay at the reversing edge of the next pass.

[0083] The physical meaning of the frequency reduction tolerance value is the upper limit of the acceptable frequency of soft spot occurrences within a single pass. If this upper limit is exceeded, it is considered that inter-pass overlapping grinding is required.

[0084] Specifically, during the equipment commissioning phase, select steel billets from the same heat that have been confirmed to have no internal defects by ultrasonic flaw detection as standard steel billets for normal grinding. Perform a complete grinding cycle under the equipment design grinding process parameters, and record the total number of frequency reduction triggers caused by the triggering of soft point determination during this process. Repeat the above calibration process for no less than 5 cycles, and take the average number of frequency reduction triggers in each cycle as the tolerance value for the number of frequency reductions.

[0085] S5. Repeat the above steps until the grinding is complete.

[0086] After each grinding cycle is completed, in order to ensure that the actual effect of compensation control reaches the expected level, the surface quality of the steel billet after the grinding cycle is inspected, and a decision is made on whether to continue to the next grinding cycle. Specifically, the following operations are carried out: the surface state parameters of the steel billet grinding area are obtained through a surface quality inspection device. For example, a laser roughness tester is used to obtain the surface roughness value, and an eddy current flaw detector is used to obtain the residual state of the surface defect layer.

[0087] The obtained surface condition parameters are compared with the grinding completion quality benchmark. When the surface condition parameters reach the grinding completion quality benchmark, it indicates that the surface of this batch of steel billets has met the processing requirements of the next process, and the grinding cycle is terminated. When the surface condition parameters do not reach the grinding completion quality benchmark, it indicates that the current grinding has not completely removed the surface defect layer, the next grinding cycle is started, and the process returns to step S1 to continue.

[0088] The aforementioned quality benchmark for grinding completion is pre-set by the downstream rolling process according to the process specifications.

[0089] If the number of grinding passes reaches the maximum number of grinding passes specified in the process specification, but the surface condition parameters still cannot reach the grinding completion quality standard, then the current grinding wheel grinding capacity is determined to be seriously insufficient, triggering an alarm signal and terminating the grinding cycle.

[0090] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0091] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0092] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0093] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for adaptive compensation control of grinding wheel wear based on billet grinding, characterized in that, include: During this grinding cycle, the oscillating section is determined by monitoring the position feedback signal of the oscillating drive. In the uniform speed forward section, the torque current value of the spindle drive and the pressure value of the downward pressing cylinder are collected as valid data. The grinding characterization value is obtained by comparing the torque current value with the pressure value. The grinding characterization value is compared with the zero-point reference value. The current working condition is determined as hard point, soft point or true wear of grinding wheel based on the deviation direction and change range. The zero-point reference value is determined based on the torque current no-load value read by the grinding wheel under no-load condition before the grinding starts. When a hard point is identified, the set pressure of the downward pressure cylinder is reduced and the feed direction position is locked. When a soft mass is identified, the operating frequency of the oscillating driver is reduced and the frequency reduction trigger is recorded. When the grinding wheel is determined to be truly worn, the feed increment is added to the feed setpoint at each reversal moment; When the grinding cycle reaches the end, the cumulative number of frequency reduction triggers is counted. If the limit is exceeded, the dwell time at the commutation edge is increased in the next cycle. Repeat the above steps until the grinding is complete; The zero-point reference value is determined in the following manner: Before the first grinding and after each grinding cycle, the grinding wheel is in an unloaded rotating state and the pressure cylinder is completely depressurized. At this time, the pressure value is zero. Under this state, the torque current unload value of the spindle drive is read. The no-load value of torque current is used as the equivalent reference value of grinding characterization under zero pressure conditions, and is recorded as the zero-point reference value of the current grinding pass. The specific process of reducing the operating frequency of the swing driver and recording this frequency reduction trigger is as follows: After acquiring the soft mass determination signal, a frequency down-adjustment command is output to the swing driver, and the trigger event of this frequency adjustment command is recorded in the cumulative counter as a frequency down-adjustment trigger record. Maintain the output state of the frequency adjustment command, continuously acquire the deviation change range of each valid data, and when the deviation of multiple consecutive adjacent data is no longer negative, cancel the frequency adjustment command and restore the operating frequency of the swing drive to the set value before adjustment. The process of increasing the dwell time at the reversal edge in the next pass is as follows: When the grinding process reaches the end of the billet in this pass, the current value of the cumulative counter is read to obtain the total number of frequency reduction triggers in this pass; When the total number of frequency reduction triggers exceeds the tolerance value for the number of frequency reductions, the swing control parameters are adjusted before the start of the next pass to extend the reversal pause time of the swing head at the left and right boundaries of the billet width direction; otherwise, the current reversal pause time remains unchanged.

2. The adaptive compensation control method for grinding wheel wear based on billet grinding as described in claim 1, characterized in that: The specific process for determining the head-swinging segment is as follows: A position encoder is installed on the output shaft of the oscillating drive. The position encoder generates pulse signals as the output shaft rotates, which serve as position feedback signals for the oscillating drive. The control system converts the cumulative amount of pulse signals into the real-time position value of the grinding wheel head in the width direction of the billet, and uses the pre-calibrated position values ​​of the grinding wheel head at the left and right limit positions of the swing stroke as the left boundary value and the right boundary value, respectively. The real-time position value is compared with the left boundary value and the right boundary value respectively: when the real-time position value is simultaneously between the left boundary value and the right boundary value, and the difference between the real-time position value and the left and right boundary values ​​is greater than the edge threshold, it is determined that the head swing is currently in the uniform speed forward segment. When the difference between the real-time position value and the left boundary value is less than or equal to the edge threshold, or when the difference between the real-time position value and the right boundary value is less than or equal to the edge threshold, it is determined that the head is currently in the reversal segment.

3. The adaptive compensation control method for grinding wheel wear based on billet grinding as described in claim 1, characterized in that: The process of acquiring the torque current value of the spindle drive and the pressure value of the downward hydraulic cylinder as valid data is as follows: When the uniform speed forward section is determined, the pressure value of the pressing oil cylinder is continuously monitored. When the pressure is stable and not zero, a sampling trigger signal is sent to the spindle driver and pressure transmitter. The torque current value and pressure value are read and combined into a valid data. When the system is determined to be in a reversing phase or the pressure value is zero, data acquisition is paused. Data acquisition will resume once the system is in the next constant-speed forward phase and the pressure value returns to a non-zero state.

4. The adaptive compensation control method for grinding wheel wear based on billet grinding as described in claim 1, characterized in that: The specific process for determining the current operating condition based on the direction and magnitude of deviation is as follows: The deviation is obtained by subtracting the zero-point reference value from the grinding characterization value of each valid data point. Subtracting the deviation of the previous valid data from the deviation of the current valid data yields the magnitude of the deviation change between adjacent data. If the difference between the grinding characterization values ​​of adjacent valid data is positive and the difference exceeds the mutation threshold, it is recorded as a positive mutation event. If the deviation of multiple consecutive valid data after the event is positive and the absolute value of the deviation change is close to zero, it is determined that a hard point has been encountered. If the difference between the grinding characterization values ​​of adjacent valid data is negative and the absolute value of the difference exceeds the mutation threshold, it is recorded as a negative mutation event. If the deviation of multiple consecutive valid data after the event is negative and the absolute value of the deviation change is close to zero, it is determined that a soft point has been encountered. If no positive or negative mutation event is triggered, and the deviation of multiple consecutive valid data is negative, and the average absolute value of the deviation of the second half of the data arranged in the order of collection time is greater than the average absolute value of the deviation of the first half of the data, then it is determined to be true wear of the grinding wheel.

5. The adaptive compensation control method for grinding wheel wear based on billet grinding as described in claim 1, characterized in that: The specific process of reducing the set pressure of the downward pressing cylinder and locking the feed direction position is as follows: After obtaining the hard point determination signal, an unloading command is output to the pressure control valve of the hydraulic system, so that the working pressure of the pressing cylinder is reduced from the current set value. At the same time, a position locking signal is output to the feed drive system to keep the displacement setpoint in the feed direction constant and prevent the grinding wheel from continuing to feed beyond the current cutting depth; Maintain the output status of the unloading command and position lock signal, continuously acquire the deviation of each valid data, and when the deviation of multiple consecutive adjacent data is no longer positive, cancel the unloading command and position lock signal, so that the working pressure of the pressing cylinder is restored to the set value before adjustment, and at the same time restore the displacement control in the feed direction.

6. The adaptive compensation control method for grinding wheel wear based on billet grinding as described in claim 1, characterized in that: The specific process of adding the increment to the given value at each commutation instant is as follows: After obtaining the true wear determination signal of the grinding wheel, at the beginning of each swing of the grinding wheel head to the edge of the billet and entering the reversing section, a feed increment command is superimposed on the feed drive system; The feed increment command is triggered once at the start of each reversal. After the head swings away from the reversal segment and enters the uniform forward segment, the execution of the current superimposed command stops, and it is triggered again at the start of the next reversal.

7. The adaptive compensation control method for grinding wheel wear based on billet grinding as described in claim 1, characterized in that: The specific process of repeating the above steps until the grinding is completed is as follows: After each grinding cycle is completed, the surface condition parameters of the steel billet grinding area are obtained through a surface quality detection device. The surface condition parameters are compared with the grinding completion quality benchmark. When the grinding completion quality benchmark is reached, the grinding cycle is terminated; otherwise, the next grinding cycle is started.

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