A method for adaptive pressure boost commutation control of a hot press forming gas supply system

Abstract

This invention belongs to the field of booster reversing control technology, specifically relating to a booster adaptive reversing control method for a hot-press forming gas supply system. The method includes: converting piston displacement into a uniform end distance to the proximal or distal mechanical end; screening the effective stroke and identifying the actual steering clearance, measured overtravel, reversing response delay time, and representative value of the piston deceleration after reversing; forming an upper bound for the reversing response delay time, a lower bound for the piston deceleration, and an upper envelope for the measured overtravel based on the effective stroke; constructing a safe overtravel envelope by combining the absolute value of the local piston movement velocity before the reversing command; determining the physical target reversing distance by the sum of the safe clearance and the safe overtravel envelope; directly retracting safely when the physical target reversing distance increases, and gradually approaching according to the dispersion step length when it decreases; and setting cylinder collision protection, stall protection, and interlock shutdown protection. This invention can adjust the reversing position according to changes in reversing hysteresis and braking capacity, balancing mechanical end safety and effective stroke utilization.

Description

Technical Field

[0001] This invention relates to the field of booster commutation control technology. More specifically, this invention relates to a booster adaptive commutation control method for a hot-press forming gas supply system. Background Technology

[0002] In the hot press molding gas supply system, during mold inflation, pressurization, pressure holding, and gas recovery, the gas needs to be repeatedly compressed by a hydraulically driven reciprocating compressor cylinder. When the piston of the hydraulically driven reciprocating compressor cylinder reaches near the end of its stroke, the flow direction of the hydraulic oil needs to be changed, causing the piston to stop moving towards the current mechanical end and move in the opposite direction. As the bottle pressure, mold pressure, hydraulic oil temperature, and the target hydraulically driven reciprocating compressor cylinder piston speed change, the time required for the hydraulic reversing valve to receive the hydraulic reversing command and generate the reverse driving force, as well as the continued forward distance of the target hydraulically driven reciprocating compressor cylinder piston, will also change.

[0003] Existing gas booster devices already employ hydraulic drive to achieve gas pressurization. For example, patent document CN201407218Y discloses a gas booster device that uses a floating piston to separate the booster chamber and oil chamber, drives the floating piston through a hydraulic oil pump, and has an anti-collision block at the end of the floating piston; patent document CN216198873U discloses a high-pressure diaphragm compressor that uses a hydraulic pump, a reversing valve, and a booster cylinder to drive a diaphragm to compress gas. The aforementioned prior art mainly achieves high-pressure gas output through a hydraulic drive structure and uses anti-collision blocks or mechanical structures to withstand the impact that may occur when the piston approaches its end.

[0004] Regarding the reversing control of a hydraulically driven gas compressor, patent document US10167857B2 discloses a method of monitoring the piston speed, driving liquid temperature, and load pressure acting on the piston during the piston stroke, and controlling the driving force to reverse based on the monitored data; the patent document also uses proximity sensors to detect the moment when the piston passes a predetermined position, and calculates the piston speed based on the distance between the two proximity sensors and the detection time.

[0005] Based on the disclosed information in the prior art, existing reversing controls typically employ pre-set stroke positions or indirectly adjust the reversing timing based on piston speed, driving fluid temperature, and load pressure. After a hydraulic reversing command is issued, the hydraulic reversing valve still needs to complete valve core movement, hydraulic circuit depressurization, and repressurization. The piston of the target hydraulically driven reciprocating compressor cylinder will continue to move towards the mechanical end. When the bottle pressure, hydraulic oil temperature, sealing friction, and gas reaction force change, the same reversing command position may produce different actual reverse positions. If the reversing command position is set too close, there is a risk that the piston of the target hydraulically driven reciprocating compressor cylinder may enter the mechanical end region; if the reversing command position is set too far, the effective stroke of the target hydraulically driven reciprocating compressor cylinder cannot be fully utilized; abnormal reversing data generated during emergency stops, stalls, cylinder collisions, and pressure start-stop changes may also cause subsequent reversing positions to change incorrectly. Summary of the Invention

[0006] To address the technical problems in existing hot-pressing gas supply systems, such as the difficulty in simultaneously avoiding mechanical end collisions and fully utilizing the effective stroke when the reversing response of the hydraulically driven reciprocating compression cylinder is delayed and braking capacity changes, and the tendency for abnormal stroke data to cause subsequent reversing position inaccuracies, this invention provides a pressurization adaptive reversing control method for hot-pressing gas supply systems. The method includes: performing a sliding average of the zero-point correction piston displacement to obtain a filtered piston displacement, and converting the filtered piston displacement into the end distance from the target hydraulically driven reciprocating compression cylinder piston to the target mechanical end; determining the effective stroke from strokes that meet the conditions of automatic operation, fault-free operation, and stable pressure start-stop judgment; and outputting a hydraulic reversing command and latching the reversing command position, reversing command time, and a marker of the reversing command event when the end distance reaches the current reversing command distance. The absolute value of the local piston speed before the reversing command is determined when the piston of the hydraulically driven reciprocating compression cylinder approaches the current reversing command position. Based on the reverse confirmation event after the hydraulic reversing command is output, the actual steering clearance, measured overtravel, reversing response delay time, and representative value of the stroke piston deceleration are determined. Based on the effective stroke, the upper bound of the reversing response delay time, the lower bound of the piston deceleration, and the upper envelope of the measured overtravel are formed. Combined with the absolute value of the local piston speed before the reversing command, the predicted overtravel and safe overtravel envelope are obtained. The sum of the safe clearance and the safe overtravel envelope is determined as the physical target reversing distance. When the physical target reversing distance is greater than the current reversing command distance, the reversing command distance of the next co-directional stroke is directly increased. When the physical target reversing distance is less than or equal to the current reversing command distance, the reversing command distance of the next co-directional stroke is decreased by an offset step length not exceeding the release distance.

[0007] Preferably, the end distance is based on Determined; among them, For the displacement of the filter piston, For the coordinates of the target machine end, The end direction coefficient, For the target mechanical end index, and Pick or , Indicates the proximal end. Indicates the remote end, , , , , To effectively calibrate the travel distance, This represents the distance between the ends.

[0008] Preferably, the determination of the reverse confirmation event includes: generating a reverse confirmation event when the sign of the piston movement speed of the target hydraulically driven reciprocating compression cylinder is opposite to the sign of the forward movement direction, the absolute value of the piston movement speed of the target hydraulically driven reciprocating compression cylinder is greater than the reverse confirmation speed threshold, and the preset reverse confirmation sampling number is maintained continuously.

[0009] Preferably, determining the actual steering clearance, measured overtravel, steering response delay time, and representative value of stroke piston deceleration based on the reverse confirmation event after the hydraulic steering command output includes: determining the difference between the steering command distance and the actual steering clearance as the measured overtravel; determining the sampling time at which the actual steering clearance is first reached between the steering command time and the reverse confirmation event as the actual reverse sampling time; determining the last sampling time at which the absolute value of the target hydraulically driven reciprocating compression cylinder piston movement speed reaches its maximum value between the steering command time and the actual reverse sampling time as the deceleration start sampling time; determining the difference between the timestamp corresponding to the deceleration start sampling time and the steering command time as the steering response delay time; and determining the median of the local piston deceleration between the deceleration start sampling time and the actual reverse sampling time as the representative value of stroke piston deceleration, wherein the local piston deceleration characterizes the degree of speed attenuation of the target hydraulically driven reciprocating compression cylinder piston during the deceleration phase after steering and between adjacent sampling times.

[0010] This invention determines the actual steering clearance by the minimum end distance within the interval, obtains the actual forward distance after the hydraulic steering command is issued by the difference between the steering command distance and the actual steering clearance, and divides the steering response delay stage and the piston deceleration stage by the last sampling moment when the absolute value of the piston movement speed reaches its maximum value. The obtained measured overtravel, steering response delay time and stroke piston deceleration representative values ​​correspond to different actual motion processes, avoiding the piston deceleration stage being repeatedly included in the steering response delay stage.

[0011] Preferably, the determination of the predicted overtravel includes: for any target mechanical end and effective stroke, the predicted overtravel is determined according to... Determined; among them, To predict overtravel, This represents the absolute value of the local piston velocity before the reversing command. This is the upper bound of the commutation response delay time. This is the lower bound of piston deceleration.

[0012] This invention adds the continuing travel distance during the reversing response delay stage to the piston braking distance during the piston deceleration stage to form the predicted overtravel. It uses a longer reversing response delay time and a weaker piston braking capacity as the calculation basis. The prediction result is jointly determined by the current forward movement speed, the hysteresis of the hydraulic reversing valve, and the piston braking capacity of the target hydraulically driven reciprocating compression cylinder. Thus, when the operating conditions change, the distance result corresponding to the actual continuing travel trend is obtained.

[0013] Preferably, the determination of the safe overrange envelope includes: ;in, For safe overrange envelope, To predict overtravel, To measure the overrange upper envelope, The maximum absolute error in displacement difference measurement. This represents the absolute value of the local piston velocity before the reversing command. The sampling period is denoted by 'max', which indicates taking a larger value.

[0014] This invention takes the larger result between the predicted overtravel and the measured overtravel envelope, and superimposes the maximum absolute error of displacement difference measurement and the movement distance that may occur during sampling, so that the safe overtravel envelope simultaneously includes the current motion state, the actual running result, the position measurement error and the discrete sampling error.

[0015] Preferably, when the physical target reversing distance is greater than the current reversing command distance, the ratio of the physical target reversing distance to the nominal resolution of the piston displacement sensor is rounded up, and the product of the rounded result and the nominal resolution is determined as the reversing command distance for the next co-directional stroke.

[0016] When the reversing distance of the physical target is greater than the current reversing command distance, the present invention directly adjusts the reversing command distance in the direction away from the mechanical end of the target. The distance is rounded according to the nominal resolution of the piston displacement sensor, so that the hydraulic reversing command can be issued in advance without going through multiple strokes for step-by-step correction after the safety overtravel envelope is increased. At the same time, it ensures that the adjusted reversing position can be reliably identified by the piston displacement sensor and the control program.

[0017] Preferably, when the physical target reversing distance is less than or equal to the current reversing command distance, the difference between the current reversing command distance and the physical target reversing distance is determined as the release distance. The maximum departure distance not greater than the release distance is selected from the ordered departure distance set corresponding to the target mechanical end, and the difference between the current reversing command distance and the maximum departure distance is determined as the reversing command distance for the next co-directional stroke. When there is no departure distance not greater than the release distance, the reversing command distance for the next co-directional stroke remains unchanged.

[0018] This invention limits the difference between the current reversing command distance and the physical target reversing distance to a releaseable distance, and only selects the maximum step length not greater than the releaseable distance to reduce the reversing command distance, so that the reversing position can gradually approach the target mechanical end without exceeding the physical target reversing distance; this step-by-step adjustment process can extend the effective stroke and reduce the reversing state fluctuation caused by a single large change in distance.

[0019] Preferably, after initial commissioning, recalibration of the piston displacement sensor, or replacement of the hydraulic directional valve, at least five low-speed no-load test runs are performed with the proportional valve opening at 20%. The maximum directional response delay time, the minimum stroke piston deceleration representative value, and the maximum measured overtravel during the low-speed no-load test runs are written into the corresponding cyclic arrays of directional response delay time, stroke piston deceleration representative value, and measured overtravel at the near and far ends, respectively.

[0020] Preferably, the method further includes: detecting the rising edges of the proximal cylinder collision mark and the distal cylinder collision mark respectively, and recording each rising edge as a corresponding cylinder collision event; setting the proximal cylinder collision mark when the distance between the proximal ends is less than 0.1 mm, setting the distal cylinder collision mark when the distance between the distal ends is less than 0.1 mm, outputting a stall alarm when the cylinder collision mark lasts for 5 seconds; outputting a cylinder collision alarm when the cumulative number of cylinder collision events reaches 3 within 20 seconds, and outputting an interlock shutdown state when the cumulative number reaches 5.

[0021] This invention detects the proximal end distance and the distal end distance to form a cylinder collision indicator, and outputs a stall alarm, a cylinder collision alarm, and an interlock shutdown status sequentially according to the duration of the cylinder collision indicator and the cumulative number of cylinder collision events, so that single end abnormalities, continuous end abnormalities, and short-term repetitive end abnormalities can be handled in a graded manner; this protection process is independent of the adaptive reversing command distance calculation, and can still stop the operation of the target hydraulically driven reciprocating compression cylinder when the piston displacement sensor fails, the hydraulic reversing valve is stuck, or the hydraulic oil circuit is abnormal.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. To address the problem that fixed reversing positions cannot reflect actual reversing lag, this invention converts the near-end mechanical end and the far-end mechanical end into a unified end distance judgment relationship, and obtains the measured overtravel based on the actual steering position after the hydraulic reversing command is issued. Each effective stroke obtained in this way can form a complete running record from the reversing command position to the actual reverse position.

[0024] 2. This invention combines the predicted overtravel formed by the current forward motion state with the upper envelope of the measured overtravel formed by the effective stroke, and superimposes the safety clearance, position measurement error and the moving distance during sampling to form the physical target reversing distance. The reversing command distance obtained in this way can be adjusted according to the response hysteresis of the hydraulic reversing valve and the piston braking capability of the target hydraulically driven reciprocating compression cylinder.

[0025] 3. This invention adopts direct yielding in the safe direction and gradual approaching of the distance step length in the effective stroke increasing direction. It is equipped with independent cylinder collision protection, stall protection and interlock shutdown protection. In dangerous conditions, it can quickly change the reversing position or stop operation. In stable conditions, it can gradually increase the effective stroke of the target hydraulically driven reciprocating compression cylinder. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a pressurization adaptive reversing control method for a hot-press forming gas supply system according to the present invention. Detailed Implementation

[0027] 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, not all, of the embodiments of the present invention. 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.

[0028] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] This invention discloses a pressurization adaptive reversing control method for a hot-press forming gas supply system. The hot-press forming gas supply system includes a low-pressure bottle group, a medium-pressure bottle group, a high-pressure bottle group, a mold, a first hydraulically driven reciprocating compressor cylinder, a second hydraulically driven reciprocating compressor cylinder, a piston displacement sensor, a hydraulic reversing valve, a proportional valve, a pressure sensor, a temperature sensor, and a programmable logic controller (PLC). The target hydraulically driven reciprocating compressor cylinder is the currently controlled object among the first and second hydraulically driven reciprocating compressor cylinders. The target hydraulically driven reciprocating compressor cylinder reciprocates under the drive of the hydraulic reversing valve to increase pressure. The PLC collects the piston displacement, bottle group pressure, hydraulic oil temperature, and fault status of the target hydraulically driven reciprocating compressor cylinder. Based on the measured overtravel formed by the piston of the target hydraulically driven reciprocating compressor cylinder continuing to move towards the target mechanical end after the hydraulic reversing command is issued, the PLC independently and adaptively updates the near-end reversing command distance and the far-end reversing command distance. Figure 1 This includes steps S1-S9:

[0030] In this embodiment, the pressure of the medium-pressure cylinder group is 30MPa to 35MPa, the pressure of the high-pressure cylinder group is 80MPa to 90MPa, and the mold design pressure is 70MPa. The hot pressing molding gas supply system first pressurizes the mold with flat pressure through the medium-pressure cylinder group, and then pressurizes the mold to the target pressure through the high-pressure cylinder group. After the mold pressure is maintained, nitrogen is recovered from the medium-pressure cylinder group and the low-pressure cylinder group in sequence. Since the pressure of the medium-pressure cylinder group, the pressure of the high-pressure cylinder group, the mold pressure and the hydraulic oil temperature change with the hot pressing molding cycle, the reversing response delay time and the actual braking capacity of the target hydraulically driven reciprocating compression cylinder piston in different reciprocating strokes are not constant.

[0031] S1: Establish unified end distance coordinates and basic safety boundaries.

[0032] It should be noted that the piston displacement sensor outputs an electrical signal that changes the effective calibrated stroke along the target hydraulically driven reciprocating compression cylinder. The same coordinate judgment rules are required for the near end and the far end of the mechanical cylinder. Therefore, this invention converts the piston displacement sensor output into the end distance from the current position of the piston of the target hydraulically driven reciprocating compression cylinder to the target mechanical end, so that the end distance decreases as the piston of the target hydraulically driven reciprocating compression cylinder gets closer to either target mechanical end.

[0033] First, after the hot-press forming air supply system has been depressurized and entered maintenance mode, the effective calibration stroke between the proximal and distal mechanical ends is determined based on the structural drawings and actual mechanical dimensions of the target hydraulically driven reciprocating compression cylinder. Using standard measuring tools, the standard distance between the piston of the target hydraulically driven reciprocating compression cylinder and the proximal mechanical end is obtained at two or more calibration positions without contacting the proximal and distal mechanical ends. The original output value of the piston displacement sensor is then linearly calibrated against the corresponding standard distance. The coordinates of the proximal mechanical end in the zero-point correction coordinate system are set based on the linear calibration result. The coordinates of the remote mechanical end in the zero-point correction coordinate system are set as follows: The zero-point corrected piston displacement is obtained by performing zero-point correction and range conversion on the real-time raw output value of the piston displacement sensor. .

[0034] Then, for the target mechanical end Set the end direction coefficient The end orientation coefficient corresponding to the proximal mechanical end is The end orientation coefficient corresponding to the remote mechanical end is Thus, the end distance is constructed:

[0035]

[0036] In the formula, To correct the piston displacement at zero point The target hydraulically driven reciprocating compression cylinder piston is at its current position from the target mechanical end. The distance between the ends, in millimeters; This is a zero-point correction for piston displacement, expressed in millimeters. The normal range of values ​​is... ; The coordinates of the target mechanical end are in millimeters. hour, ,when hour, ; For the target mechanical end index, the value set is: ; For the target mechanical end direction coefficient, when hour, ,when hour, .

[0037] When the target mechanical end is a proximal mechanical end, and Substituting the end distances yields When the target mechanical end is a remote mechanical end, and Substituting the end distances yields Therefore, regardless of whether the piston of the target hydraulically driven reciprocating compression cylinder moves towards the near end of the machine or towards the far end of the machine, a decrease in the end distance indicates that the piston of the target hydraulically driven reciprocating compression cylinder is approaching the end of the target machine.

[0038] Furthermore, proximal safety clearance and remote safety clearance These represent the minimum distances that the piston of the target hydraulically driven reciprocating compression cylinder should maintain with the proximal and distal mechanical ends when the piston is actually reversing, respectively, and the proximal safety clearance. and remote safety clearance Based on the minimum allowable remaining distance of the cylinder head structure, the effective length of the buffer structure, the allowable deformation of the sealing components, the assembly tolerances of the target hydraulically driven reciprocating compression cylinder, and the maximum absolute error of the displacement difference measurement, the measurement is performed according to the maximum absolute error of the cylinder head structure, the effective length of the buffer structure, the allowable deformation of the sealing components, and the assembly tolerances and displacement differences of the target hydraulically driven reciprocating compression cylinder. The determination process includes: determining the minimum permissible remaining mechanical clearance based on the cylinder head structure, buffer structure, and sealing components; adding the minimum permissible remaining mechanical clearance, the upper limit of assembly tolerance, and the maximum absolute error of displacement difference measurement to obtain the calculated safety clearance value; and using amplitude limiting processing to determine the near-end safety clearance. and remote safety clearance The clearance is limited to the range of 6 mm to 30 mm. When the calculated safety clearance is less than 6 mm, take 6 mm. When the calculated safety clearance is greater than 30 mm, adaptive updates are prohibited and the automatic operation of the corresponding target hydraulically driven reciprocating compression cylinder is stopped until the mechanical structure, assembly status and piston displacement sensor calibration status checks are completed.

[0039] Among them, the maximum absolute error of displacement difference measurement The maximum absolute error of displacement difference measurement is obtained through multi-position calibration: Select at least five calibration positions within the effective calibration stroke; use a standard measuring instrument to measure the standard distance between any two adjacent calibration positions; and use a piston displacement sensor to measure the distance between corresponding two calibration positions. The maximum absolute error of displacement difference measurement is determined by the maximum absolute value of the absolute difference between all measured distances and their corresponding standard distances. The maximum absolute error of the piston displacement sensor measurement can be determined by reinstalling the sensor, replacing the analog acquisition module, or re-performing zero-point calibration. .

[0040] S2: Determine the valid routes that are allowed to participate in adaptive updates.

[0041] It should be noted that the reversing data generated during emergency stops, cylinder collisions, stalls, manual adjustments, when the hydraulic reversing valve is not loaded, and during pressure start-stop judgment state switching cannot reflect the reversing dynamics under normal boosting conditions. If abnormal reversing data is used to update the upper bound of the reversing response delay time, the lower bound of the piston deceleration, or the upper envelope of the measured overtravel, it may cause erroneous changes in the reversing distance of the physical target. Therefore, this invention only accepts valid strokes that meet the preset operating conditions and have complete sampling data.

[0042] First, continuously collect data on the automatic operation mode status, the target hydraulically driven reciprocating compression cylinder's operating enable status, emergency stop status, real-time alarm status, interlock shutdown status, hydraulic directional valve loading status, near-end cylinder collision indicator, far-end cylinder collision indicator, stall alarm status, and pressure start / stop determination status, and collect data according to the sampling cycle. The above Boolean states are written into the state circular buffer, and the data stored in the state circular buffer is kept for a period of time no less than the state stabilization confirmation time. State stability confirmation time Use 8 seconds.

[0043] Then, at the start of each current stroke, a valid stroke flag is established. Only the following conditions are valid: automatic operation mode, target hydraulically driven reciprocating compression cylinder operation enable status, emergency stop status, real-time alarm status, interlocked shutdown status, hydraulic directional valve loading status, near-end cylinder collision flag, far-end cylinder collision flag, and stall alarm status. Furthermore, the pressure start / stop determination status must be confirmed within the time frame prior to the directional command event. The current trip is determined to be a valid trip only if the change command event and the reverse confirmation event remain unchanged.

[0044] Furthermore, when the time from the start of the current journey to the occurrence of the reversing command event is shorter than the state stabilization confirmation time... At the same time, the hydraulic reversing command is still output according to the current reversing command distance, but the current stroke is not determined as a valid stroke; when any monitored Boolean state changes within the local sampling window of the reversing, the valid stroke flag is immediately canceled, and the measured overtravel, reversing response delay time and stroke piston deceleration representative value generated by the current stroke are not written into the historical cycle buffer.

[0045] It should be further added that the pressure start-stop determination state of the first hydraulically driven reciprocating compressor cylinder is formed based on the pressure of the low-pressure bottle group, the pressure of the medium-pressure bottle group, and the preset pressure start-stop threshold of the first hydraulically driven reciprocating compressor cylinder. The pressure start-stop determination state of the second hydraulically driven reciprocating compressor cylinder is formed based on the pressure of the medium-pressure bottle group, the pressure of the high-pressure bottle group, and the preset pressure start-stop threshold of the second hydraulically driven reciprocating compressor cylinder. The pressure start-stop determination state is only used as a valid stroke determination condition and does not directly enter the calculation of the measured overtravel, predicted overtravel, safe overtravel envelope, or physical target reversal distance.

[0046] S3: Collect zero-point correction piston displacement and identify reversing command events.

[0047] It should be noted that the sampled values ​​of the piston displacement sensor contain analog conversion errors, mechanical vibrations, and electrical noise. Directly using adjacent original sampled values ​​to calculate the piston speed of the target hydraulically driven reciprocating compression cylinder can easily lead to repeated changes in the speed sign, which in turn causes the reversing command event or reverse confirmation event to be repeatedly identified. Therefore, this invention filters the zero-point correction piston displacement and limits each current stroke to only one reversing command event.

[0048] First, the periodic task is performed according to the sampling period. Collect zero-point correction piston displacement, and set the sampling period. Set to 0.01 seconds.

[0049] Continuous The zero-point corrected piston displacement samples are stored in a circular buffer, and the filtered piston displacement is obtained by moving average. Let be the moving average window length, and The value is a positive integer not less than 5; in this embodiment, it is 10. When the first effective zero-point correction piston displacement is obtained after the hot-pressing gas supply system is started, the first effective zero-point correction piston displacement is copied to the entire circulating buffer. This provides a storage location to prevent undefined data from appearing when the circular buffer is not full.

[0050] Then, calculate the sampling times of two adjacent sampling times. and The difference in the displacement of the filtered piston is used to calculate the ratio of this difference to the sampling period, thus obtaining the sampling time. Target hydraulically driven reciprocating compression cylinder piston movement speed Among them, the target hydraulically driven reciprocating compression cylinder piston movement speed The positive or negative sign indicates the direction of piston movement in the target hydraulically driven reciprocating compression cylinder, and the piston speed in the target hydraulically driven reciprocating compression cylinder. The absolute value of indicates the speed of piston movement in the target hydraulically driven reciprocating compression cylinder.

[0051] Next, when the target hydraulically driven reciprocating compression cylinder piston moves towards the target mechanical end... The movement, and the displacement of the filtered piston. Calculated end distance When the distance changes from greater than the current reversing command distance to less than or equal to the current reversing command distance, a reversing command event is generated, a hydraulic reversing command is output to the hydraulic reversing valve, and the sampling time index of the reversing command event is latched. Reversing command timing , reversal command position The direction indicator for forward movement and the absolute value of the local piston speed before the reversing command. The zero-point correction piston displacement is... The target hydraulically driven reciprocating compression cylinder piston is at its current position from the target mechanical end. End distance As the first One effective stroke at the target mechanical end Reversing command distance .

[0052] Furthermore, the absolute value of the local piston speed before the reversing command is taken as the arithmetic mean of the absolute values ​​of the three consecutive piston speeds before the reversing command event occurs. The obtained absolute value of the local piston speed before the reversing command is used to characterize the actual speed of the piston of the target hydraulically driven reciprocating compression cylinder near the reversing position before the hydraulic reversing command is issued. When there are less than three valid piston speed sampling values ​​before the reversing command event occurs, or the absolute value of the local piston speed before the reversing command is... Not greater than the reverse confirmation speed threshold At the same time, hydraulic reversing commands are still output, but the valid stroke flag for the current stroke is canceled; the reversing command event latch flag remains valid until the end of the current stroke, so that the reversing command time and reversing command position cannot be latched repeatedly within the same current stroke.

[0053] When the target hydraulically driven reciprocating compression cylinder is stationary, at least 100 zero-point correction piston displacement samples are continuously collected. The results are then calculated based on the absolute value of the difference between adjacent filtered piston displacements and the sampling period. The ratio is used to calculate the equivalent velocity of stationary noise, and twice the maximum value among all equivalent velocities of stationary noise is set as the reverse confirmation velocity threshold. .

[0054] S4: Identify the reverse confirmation event, determine the actual reverse time, and calculate the measured overtravel.

[0055] It should be noted that after receiving the hydraulic reversing command, the hydraulic reversing valve needs to go through the process of electromagnetic coil action, valve core movement, hydraulic oil circuit depressurization and repressurization. The piston of the target hydraulically driven reciprocating compression cylinder will continue to move towards the target mechanical end after the hydraulic reversing command is issued. The fact that the piston speed of the target hydraulically driven reciprocating compression cylinder is close to 0 for a short time cannot prove that the direction of movement has changed. Therefore, this invention confirms the reverse event by changing the direction of movement, the reverse movement speed exceeding the reverse confirmation speed threshold, and the number of reverse confirmation samplings continuously maintained in the reverse state. The actual reverse time is determined by backtracking based on the minimum end distance between the reversing command event and the reverse confirmation event.

[0056] First, after the reversing command event occurs, a reversing local sampling window is opened, and the piston displacement, end distance, and target hydraulically driven reciprocating compression cylinder piston movement speed are continuously cached and filtered. When the sign of the target hydraulically driven reciprocating compression cylinder piston movement speed is opposite to the forward movement direction sign, and the absolute value of the target hydraulically driven reciprocating compression cylinder piston movement speed is greater than the reverse confirmation speed threshold, the sampling window is activated. And the above state is maintained continuously for a number of reverse confirmation samples. At that time, a reverse confirmation event is generated and the sampling time index of the reverse confirmation event is recorded. The reverse confirmation sampling number is 3.

[0057] Then, index at the sampling time of the commutation command event. Index of sampling time to reverse confirmation event Between these points, the minimum end distance is selected from all cached end distances as the actual steering clearance. If no reverse confirmation event is generated, the minimum value calculation is not performed, and the valid travel flag for the current travel is canceled. The sampling time index of the reversing command event is set. Index of sampling time to reverse confirmation event The first time the actual steering clearance was reached The sampling time index is determined as the actual reverse sampling time index. Index the actual backsampling time The corresponding timestamp is determined to be the actual reverse time. This ensures that the actual reversal time corresponds to the moment when the piston of the target hydraulically driven reciprocating compression cylinder reaches its minimum end distance.

[0058] Among them, the minimum value of the distance between the ends of the local sampling window is used to determine the actual steering clearance, which can cover the situation where the piston movement speed of the target hydraulically driven reciprocating compression cylinder fluctuates around 0. The smaller the actual steering clearance, the closer the actual reverse position of the piston of the target hydraulically driven reciprocating compression cylinder is to the target mechanical end.

[0059] Next, the difference between the reversing command distance and the actual steering clearance is calculated to obtain the measured overtravel. The reversing command distance represents the distance between the piston of the target hydraulically driven reciprocating compression cylinder and the end of the target machine when the hydraulic reversing command is issued. The actual steering clearance represents the minimum distance between the piston of the target hydraulically driven reciprocating compression cylinder and the end of the target machine when the piston is actually reversed. The difference between the two is the distance that the piston of the target hydraulically driven reciprocating compression cylinder continues to move towards the end of the target machine after the hydraulic reversing command is issued. The larger the measured overtravel, the greater the distance that continues to move forward due to the current reversing lag and motion inertia.

[0060] It should be added that when the measured overtravel... When the value is less than 0, it indicates that there is an error in the reversing command event, reverse confirmation event, end direction coefficient, or piston displacement sensor direction configuration. The current stroke is judged as an invalid stroke and is not written to the historical loop buffer.

[0061] Furthermore, the index at the sampling time of the reversing command event. Index to the actual reverse sampling time Between these points, identify all sampling moments when the absolute value of the piston speed of the target hydraulically driven reciprocating compression cylinder reaches its maximum value, and determine the last sampling moment as the index of the deceleration start sampling moment. Index of the time when deceleration begins sampling The corresponding timestamp is determined as the deceleration start time. ,when Cancel the valid trip flag for the current trip.

[0062] Furthermore, the difference between the reversing command time and the deceleration start time is calculated to obtain the reversing response delay time; when the calculation result is less than 0, the valid travel flag of the current travel is canceled.

[0063] S5: Identify the upper bound of the commutation response delay time and the lower bound of the piston deceleration.

[0064] It should be noted that the predicted overtravel needs to reflect the reversing response delay stroke during the period when the hydraulic reversing valve has not yet formed an effective braking effect, and the piston braking distance of the target hydraulically driven reciprocating compression cylinder piston from the point where the absolute value of the local piston movement speed before the reversing command decreases to 0. The longer the reversing response delay time or the weaker the actual braking capacity, the greater the distance that the target hydraulically driven reciprocating compression cylinder piston continues to move towards the target mechanical end. Therefore, this invention uses the larger reversing response delay time in the effective stroke to form the upper limit of the reversing response delay time, and uses the smaller stroke piston deceleration representative value in the effective stroke to form the lower limit of the piston deceleration.

[0065] First, the index at the start of deceleration sampling. Index to the actual reverse sampling time Between each adjacent sampling time point, the local piston deceleration is calculated:

[0066]

[0067] In the formula, For the first Local piston deceleration at each sampling time, in millimeters per second squared; For the first The target hydraulically driven reciprocating compression cylinder piston movement speed at each sampling moment is expressed in millimeters per second. For the first The target hydraulically driven reciprocating compression cylinder piston movement speed at each sampling moment is expressed in millimeters per second. The sampling period; This is the index for the deceleration sampling interval, with a value range of [value range missing]. ; This is the absolute value operator; only values ​​that satisfy the condition are retained. The local piston deceleration will satisfy The sampled values ​​are discarded as speed fluctuation data; the local piston deceleration characterizes the degree of speed decay of the target hydraulically driven reciprocating compression cylinder piston during the deceleration phase after reversal between adjacent sampling times.

[0068] Then, all local piston decelerations within the deceleration sampling interval are sorted by numerical value, and the median is taken as the representative value of the piston deceleration of the current valid stroke. When all local piston decelerations within the deceleration sampling interval are less than or equal to 0, the median calculation is not performed, and the valid stroke flag of the current stroke is canceled.

[0069] Next, a length of [length missing] is established for each end control data block. The commutation response delay time loop array, the stroke piston deceleration representative value loop array, and the measured overtravel loop array are used to determine the commutation response delay time after the current effective stroke is completed. Representative value of piston deceleration during stroke and measured overtravel Write to the corresponding circular array and overwrite the oldest stored element.

[0070] Furthermore, in recent times In each effective stroke, the sum of the maximum commutation response delay time and one sampling period is determined as the upper bound of the commutation response delay time, and the minimum value of the representative value of the piston deceleration during the stroke is determined as the lower bound of the piston deceleration; if the number of effective strokes is insufficient... At that time, the circular array elements not covered by the effective travel remain initialized with the commutation response delay time, and the circular array elements not covered by the effective travel remain initialized with the lower bound of the piston deceleration.

[0071] Among them, the upper bound of the reversing response delay time increases with the increase of the reversing response delay time, and the lower bound of the piston deceleration decreases with the decrease of braking capacity. Both changes will increase the subsequent predicted overtravel, thereby causing the reversing distance of the physical target to change in the direction away from the mechanical end of the target. The current effective stroke data is written into the loop array before the extreme value calculation, so that the longer reversing response delay time or weaker braking capacity of the current effective stroke can be used for the reversing command distance update of the next co-directional stroke.

[0072] It should be added that the number of historical valid travel windows The values ​​range from 5 to 30; in this embodiment, 10 is used.

[0073] In addition, after the hot-pressing air supply system is put into operation for the first time, the piston displacement sensor is recalibrated, or the hydraulic reversing valve is replaced, at least five low-speed no-load test runs are performed with the minimum proportional valve opening that can maintain the stable reciprocating motion of the target hydraulically driven reciprocating compression cylinder. In this embodiment, the minimum proportional valve opening is limited to 20%, so a 20% proportional valve opening is used. The reversing response delay time, the representative value of the piston deceleration during the stroke, and the measured overtravel are recorded for the near end and far end of the target hydraulically driven reciprocating compression cylinder, respectively. The maximum reversing response delay time during the low-speed no-load test runs is used as the initial reversing response delay time, the minimum value among all representative values ​​of piston deceleration during the stroke is used as the initial lower bound of piston deceleration, and the maximum value among all measured overtravels is used as the initial upper envelope of measured overtravel. The initial reversing response delay time, the initial lower bound of piston deceleration, and the initial upper envelope of measured overtravel are used to fill the entire corresponding loop array. One storage location.

[0074] S6: Derive the predicted overrange and construct the safe overrange envelope.

[0075] It should be noted that the process from the occurrence of the reversing command event to the cessation of the piston of the target hydraulically driven reciprocating compression cylinder moving toward the target mechanical end includes a reversing response delay stage and a piston deceleration stage. During the reversing response delay stage, the piston of the target hydraulically driven reciprocating compression cylinder continues to move at approximately the absolute value of the local piston movement speed before the reversing command. During the piston deceleration stage, the piston of the target hydraulically driven reciprocating compression cylinder decreases from the absolute value of the local piston movement speed before the reversing command to 0 under the action of the reverse pressure of the hydraulic oil circuit. Therefore, the predicted overtravel is obtained by adding the reversing response delay stroke and the piston braking distance.

[0076] First, during the commutation response delay phase, the absolute value of the local piston velocity before the commutation command is... Upper bound of commutation response delay time Multiplying these values ​​yields the reversing response delay stroke. An increase in the absolute value of the local piston movement speed before the reversing command or an increase in the upper bound of the reversing response delay time will increase the reversing response delay stroke. This indicates that the piston of the target hydraulically driven reciprocating compression cylinder may continue to move a longer distance toward the target mechanical end during the period before the hydraulic reversing valve has established an effective braking effect.

[0077] Meanwhile, a uniform deceleration motion relationship is adopted during the piston deceleration phase:

[0078]

[0079] In the formula, The absolute value of the piston speed of the target hydraulically driven reciprocating compression cylinder at the end of the piston deceleration phase, in millimeters per second, when it stops moving towards the target mechanical end. ; This is the absolute value of the local piston speed before the reversing command is used at the beginning of the piston deceleration phase, expressed in millimeters per second. The signified piston acceleration, expressed in millimeters per second squared, represents the piston's acceleration along the original direction of motion in the hydraulically driven reciprocating compression cylinder. During deceleration... ; This represents the piston braking distance, measured in millimeters.

[0080] When the piston of the target hydraulically driven reciprocating compression cylinder stops moving towards the target mechanical end... The signed piston acceleration, representing the original direction of piston movement in the target hydraulically driven reciprocating compression cylinder, is taken as... ,Will and Substituting the equations into the uniformly decelerated motion relation, we get: , This is the lower bound of the piston deceleration, expressed in millimeters per square second; from this, the piston braking distance can be obtained:

[0081]

[0082] In the formula, For the first After each effective stroke is completed, the target mechanical end is... The calculated piston braking distance is in millimeters. This is the absolute value of the local piston movement speed before the reversal command, in millimeters per second. This is the lower bound of piston deceleration, expressed in millimeters per second squared; when At this time, division operation is not performed, adaptive update is prohibited, and an alarm for abnormal commutation braking capability is output.

[0083] Among them, the absolute value of the local piston movement speed before the reversing command affects the piston braking distance in a square form. When the absolute value of the local piston movement speed before the reversing command increases, the piston braking distance increases. When the lower limit of the piston deceleration decreases, the piston braking distance increases. This means that under the current working condition, the piston of the target hydraulically driven reciprocating compression cylinder needs to travel a longer distance to stop moving towards the target mechanical end.

[0084] In summary, by adding the commutation response delay stroke and the piston braking distance, the predicted overtravel is obtained:

[0085]

[0086] In the formula, For the first After each effective stroke is completed, the target mechanical end is... The calculated predicted overshoot is in millimeters. The commutation response delay is measured in millimeters. This refers to the piston braking distance, expressed in millimeters. This is the absolute value of the local piston movement speed before the reversal command, in millimeters per second. This is the upper bound of the commutation response delay time, in seconds; This is the lower bound for piston deceleration, expressed in millimeters per second squared. Index for the target mechanical end; This is the valid procedure number.

[0087] Among them, the predicted overtravel converts the hydraulic directional valve response lag and the target hydraulically driven reciprocating compression cylinder piston braking process into the same length quantity. The larger the predicted overtravel, the greater the distance that the target hydraulically driven reciprocating compression cylinder piston may continue to move towards the target mechanical end after the hydraulic directional command is issued.

[0088] Then, in the nearest of the measured overrange loop array The maximum measured overtravel value is selected from the valid travel data to obtain the upper envelope of the measured overtravel:

[0089]

[0090] In the formula, For the first After each effective stroke is completed, at the target mechanical end The measured overshoot envelope formed, in millimeters; to The nearest value in the measured overtravel loop array Each element is in millimeters. This refers to the number of historically valid travel windows. Maximum value operator for a finite non-empty set of real numbers; insufficient number of valid runs. At that time, the circular array elements not covered by the effective route retain the initial measured overrange envelope.

[0091] The measured overtravel upper envelope can include the combined effects of hydraulic directional valve friction, hydraulic oil compressibility, changes in sealing friction, and changes in gas reaction force on the measured overtravel. An increase in the measured overtravel upper envelope indicates that a larger distance has been traveled in the effective stroke.

[0092] Next, the larger value in the envelope of the predicted overtravel and the measured overtravel is taken as the main overtravel quantity, and the maximum absolute error of the displacement difference measurement and the possible movement distance within a sampling period are superimposed to obtain the safe overtravel envelope:

[0093]

[0094] In the formula, For the first After each effective stroke is completed, the target mechanical end is... The calculated safe overtravel envelope is in millimeters. The measured overtravel upper envelope is in millimeters. For predicted overtravel, the unit is millimeters; This is the maximum value operator; The maximum absolute error for displacement difference measurement, in millimeters; This is the absolute value of the local piston movement speed before the reversal command, in millimeters per second. The sampling period is expressed in seconds. The possible movement distance within one sampling period is expressed in millimeters.

[0095] Among them, the predicted overtravel uses the absolute value of the local piston movement speed before the current reversing command and the upper bound of the reversing response delay time of the effective stroke and the lower bound of the piston deceleration to reflect the current operating conditions. The measured overtravel upper envelope covers the changes in hydraulic reversing valve friction and hydraulic oil elasticity that are not fully expressed by the predicted relationship. Taking the larger value of both can avoid relying solely on the predicted data or historical measured data. The larger the safe overtravel envelope, the more the hydraulic reversing command needs to be issued at a position farther away from the end of the target machine in the next unidirectional stroke.

[0096] It should be further noted that when the current stroke is not determined to be a valid stroke, the cyclic arrays of the reversing response delay time, the cyclic arrays of the stroke piston deceleration representative values, and the cyclic arrays of the measured overtravel are not updated, and the safe overtravel envelope retains the calculation result of the previous valid stroke. Before the initialization test is completed, a conservative initial reversing command distance is used and adaptive updates are prohibited. After the initialization test is completed, the initial safe overtravel envelope is calculated based on the initial reversing response delay time, the lower bound of the initial piston deceleration, the upper envelope of the initial measured overtravel, the maximum absolute error of the displacement difference measurement, and the sampling period. Among these, the conservative initial reversing command distance... , To effectively calibrate the travel distance.

[0097] S7: Calculate the reversal distance of the physical target.

[0098] It should be noted that the actual steering clearance is equal to the reversing command distance minus the continued forward distance formed after the hydraulic reversing command is issued. In order to ensure that the piston of the target hydraulically driven reciprocating compression cylinder still retains a safe clearance when it actually reverses, the reversing command distance should be at least equal to the sum of the safe clearance and the safe overtravel envelope.

[0099] First, based on the geometric relationship between the reversing command distance, the measured overtravel, and the actual steering clearance, we obtain:

[0100]

[0101] In the formula, For the first One effective stroke at the target mechanical end The actual steering clearance, in millimeters; For the first One effective stroke at the target mechanical end The reversing command distance, in millimeters; For the first One effective stroke at the target mechanical end The measured overtravel is in millimeters; Index for the target mechanical end; This is the valid procedure number.

[0102] Then, to ensure that the actual steering clearance of the next co-directional stroke meets the requirements... Furthermore, by using a safe overtravel envelope to conservatively limit the potential overtravel in the next co-directional journey, the following constraints are established:

[0103]

[0104] In the formula, For the next co-directional stroke at the end of the target machine The reversing command distance, in millimeters; For the first The safety overtravel envelope formed after the completion of each valid journey, in millimeters; For the target mechanical end Safety clearance, in millimeters, when hour, ,when hour, ; Index for the target mechanical end; This is the currently valid line number.

[0105] Next, by moving the safety overtravel envelope to the right side of the inequality, we obtain the reversing command distance constraint for the next co-directional stroke:

[0106]

[0107] In the formula, For the next co-directional stroke at the end of the target machine The reversing command distance, in millimeters; For the target mechanical end Safety clearance, in millimeters; For safety overrange envelope, the unit is millimeters; Index for the target mechanical end; This is the currently valid line number.

[0108] Furthermore, the boundary values ​​that satisfy the above constraints are determined as the physical target reversal distance:

[0109]

[0110] In the formula, For the first After each effective stroke is completed, the target mechanical end is... The calculated reversal distance of the physical target is in millimeters. For the target mechanical end Safety clearance, in millimeters; For safety overrange envelope, the unit is millimeters; Index for the target mechanical end; This is the valid procedure number.

[0111] Specifically, when the actual overtravel of the current unidirectional stroke is equal to the safe overtravel envelope, issuing a hydraulic reversing command according to the physical target reversing distance can make the actual steering clearance equal to the safe clearance; when the actual overtravel of the current unidirectional stroke is less than the safe overtravel envelope, the actual steering clearance is greater than the safe clearance, thus retaining an additional safety margin.

[0112] It is necessary to further supplement the information regarding the physical target reversal distance. It must not be larger than the target mechanical end Conservative initial reversing command distance When the physical target changes direction distance When the calibrated conservative initial reversing command distance is insufficient to meet the sum of the safety clearance and safety overtravel envelope, the reversing command distance update is not performed, adaptive update is immediately prohibited, an insufficient reversing capability alarm is output, and the automatic operation of the corresponding target hydraulically driven reciprocating compression cylinder is stopped; when the physical target reversing distance... When the value is less than 0, the calculated data is handled as an anomaly and the conservative initial reversal command distance is restored.

[0113] S8: Execute asymmetric step-wise reversal command distance update.

[0114] It should be noted that if the physical target reversing distance is greater than the current reversing command distance, it indicates that the safe overtravel envelope has increased. Continuing to use the current reversing command distance may cause the actual rotation position of the piston of the target hydraulically driven reciprocating compression cylinder to enter the safe clearance. Therefore, a safety yield update must be performed immediately before the next unidirectional stroke. If the physical target reversing distance is less than the current reversing command distance, it indicates that there is excess distance in the current reversing command distance that can be released. However, moving closer to the target mechanical end is an effective stroke optimization. Therefore, an efficiency approximation update with step-by-step verification should be performed.

[0115] First, when the physical target changes direction distance Greater than the distance of the current reversal command And the physical target reversal distance Not greater than the conservative initial reversing command distance At that time, according to the nominal resolution of the piston displacement sensor Round down in the direction away from the target mechanical end and update the reversing command distance for the next co-directional stroke:

[0116]

[0117] In the formula, For the next co-directional stroke at the end of the target machine The reversing command distance, in millimeters; For the first The physical target reversal distance formed after a valid journey is completed, in millimeters; The nominal resolution of the piston displacement sensor is expressed in millimeters and is obtained by reading the performance parameters given by the piston displacement sensor manufacturer in the product technical specifications, product certificate, or calibration certificate. Index for the target mechanical end; The currently valid line number; This is the floor operator.

[0118] When the physical target reversal distance increases, the reversal command distance of the next same-direction journey is increased to no less than the physical target reversal distance in one go, without completing the safety backoff update through multiple effective journeys step by step, thereby avoiding the situation where the safety overtravel envelope has increased while the reversal command distance is still at the original small distance.

[0119] When the physical target changes direction distance Less than or equal to the current reversing command distance At that time, calculate the release distance:

[0120]

[0121] In the formula, For the first One effective stroke at the target mechanical end Release distance, in millimeters; The distance of the current reversal command, in millimeters; The distance of the physical target reversal, in millimeters; Index for the target mechanical end; This is the currently valid line number.

[0122] Furthermore, this embodiment sets up a proximal ordered staggered set and a distal ordered staggered set. and The elements in the set are in millimeters, and the elements are stored in descending order, each used for the target mechanical end. and The efficiency is approaching the update; it should be further noted that the values ​​in the near-end ordered discrete step length set and the far-end ordered discrete step length set are parameters of the current hot-press forming gas supply system embodiment, and the minimum discrete step length must not be less than the nominal resolution of the piston displacement sensor. For hot-press forming air supply systems of different specifications, the nominal resolution of the piston displacement sensor is used as the reference. Candidate rotor lengths are constructed using integer multiples of the specified values. For each candidate rotor length, at least five low-speed no-load reciprocating strokes are executed. The candidate rotor length is retained only if no cylinder collision or stall alarm occurs during any of the low-speed no-load reciprocating strokes, only one reversing command event is generated within each unidirectional stroke, a corresponding reverse confirmation event is generated after each hydraulic reversing command output, and the hydraulic pressure does not exceed the equipment's rated range. The piston displacement sensor, hydraulic reversing valve, proportional valve, or the effective calibration stroke is then replaced. Then, the orderly separation of the long-distance walking group was re-calibrated.

[0123] Next, based on the release distance and the target mechanical end orderly separation long collection Establish a set of candidate step sizes:

[0124]

[0125] In the formula, For the first One effective stroke at the target mechanical end The candidate set of walk lengths, with units of millimeters. For the target mechanical end orderly separation long collection A subset of and allows empty values; For the target mechanical end orderly separation long collection Candidate distance-separation element in the sample, in millimeters; To be compatible with the target mechanical end The corresponding ordered discrete set, when hour, ,when hour, ; Release distance, in millimeters; This is a symbol for the membership relationship of a set.

[0126] Then, when the candidate departure length set is not empty, the largest element in the candidate departure length set is taken as the selected departure length; when the candidate departure length set is empty, the selected departure length is set to 0, and the reversal command distance of the next co-directional trip is updated according to the selected departure length.

[0127]

[0128] In the formula, For the next co-directional stroke at the end of the target machine The reversing command distance, in millimeters; The distance of the current reversal command, in millimeters; The selected distance step length is in millimeters; Index for the target mechanical end; The current valid line number; when the candidate walk length set is empty. Therefore, the distance of the next unidirectional travel reversal command remains the same as the current reversal command distance.

[0129] Wherein, since any element in the candidate discrete step length set satisfies Therefore, the selected distance from the walking distance satisfies to satisfy This ensures that the efficiency of the updated reversing command distance will not exceed the physical target reversing distance.

[0130] It should be further added that, under the unified end distance coordinate system, a decrease in the reversing command distance indicates that the hydraulic reversing command is issued closer to the target mechanical end, while an increase in the reversing command distance indicates that the hydraulic reversing command is issued further away from the target mechanical end. When the physical target reversing distance is less than the current reversing command distance, the reversing command distance is gradually reduced according to the step length not exceeding the release distance. When the physical target reversing distance is greater than the current reversing command distance, the reversing command distance of the next co-directional stroke is directly increased to be not less than the physical target reversing distance.

[0131] S9: Implement cylinder collision protection, stall protection, and interlock shutdown protection.

[0132] It should be noted that the safety overtravel envelope and asymmetric stepped reversing command distance update are used to reduce the risk of cylinder collision during normal operation. However, piston displacement sensor failure, hydraulic reversing valve jamming, hydraulic circuit abnormality, or program parameter overrun may still cause the piston of the target hydraulically driven reciprocating compression cylinder to enter the mechanical end area. Therefore, it is necessary to set cylinder collision protection, stall protection, and interlock shutdown protection independent of adaptive update calculation.

[0133] Specifically, when the distance between the proximal end and the cylinder is less than the proximal cylinder impact threshold of 0.1 mm, a proximal cylinder impact indicator is set; when the distance between the distal end and the cylinder is less than the distal cylinder impact threshold of 0.1 mm, a distal cylinder impact indicator is set. The proximal and distal cylinder impact thresholds are used to identify abnormal mechanical end conditions before the piston of the target hydraulically driven reciprocating compression cylinder reaches the corresponding mechanical end.

[0134] Furthermore, if the near-end cylinder collision indicator or the far-end cylinder collision indicator remains continuously for 5 seconds during the stall confirmation time, the corresponding stall alarm status will be output.

[0135] Furthermore, the rising edges of the near-end cylinder collision flag and the far-end cylinder collision flag are detected separately, and the near-end cylinder collision events and the far-end cylinder collision events are counted separately. The cylinder collision event counting window is opened when the first cylinder collision event occurs, and the cylinder collision event counting window time is 20 seconds. When the corresponding cylinder collision event accumulates to the cylinder collision alarm count threshold of 3 times within the cylinder collision event counting window, a cylinder collision alarm is output. When the corresponding cylinder collision event accumulates to the cylinder collision interlock shutdown count threshold of 5 times within the cylinder collision event counting window, an interlock shutdown status is output. When the cylinder collision event counting window ends, if the cumulative number of corresponding cylinder collision events is less than the cylinder collision interlock shutdown count threshold, the cumulative number of corresponding cylinder collision events is cleared to zero, keeping the cylinder collision alarm count threshold less than the cylinder collision interlock shutdown count threshold.

[0136] In this embodiment, the analog data collected by the piston displacement sensor is stored as integer data, the zero-point corrected piston displacement, filtered piston displacement, end distance, piston movement speed, measured overtravel, reversing response delay time, representative value of stroke piston deceleration, safe overtravel envelope, and reversing command distance are stored as real data, the reversing command time, deceleration start time, and actual reversing time are stored as time data, and the automatic operation mode status, operation enable status, emergency stop status, real-time alarm status, interlock stop status, cylinder collision flag, stall alarm status, and effective stroke flag are stored as Boolean data. Independent end control data blocks are established for the near end of the first hydraulically driven reciprocating compression cylinder, the far end of the first hydraulically driven reciprocating compression cylinder, the near end of the second hydraulically driven reciprocating compression cylinder, and the far end of the second hydraulically driven reciprocating compression cylinder.

[0137] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for pressurization adaptive commutation control of a hot-pressing gas supply system, characterized in that, include: The zero-point corrected piston displacement is averaged to obtain the filtered piston displacement, and the filtered piston displacement is converted into the end distance from the piston of the target hydraulically driven reciprocating compression cylinder to the end of the target mechanical end. The effective stroke is determined from the stroke that meets the conditions of automatic operation, no faults and stable pressure start and stop judgment state. When the end distance reaches the current reversing command distance, the hydraulic reversing command is output and the reversing command position, reversing command time and the absolute value of the local piston movement speed before the reversing command, which represents the movement speed of the target hydraulically driven reciprocating compression cylinder piston when it approaches the current reversing command position before the reversing command event occurs, are stored. Based on the reverse confirmation event after the hydraulic reversing command is output, determine the actual steering clearance, measured overtravel, reversing response delay time and representative value of stroke piston deceleration. Based on the effective stroke, the upper bound of the reversing response delay time, the lower bound of the piston deceleration, and the upper envelope of the measured overtravel are formed. Combined with the absolute value of the local piston motion velocity before the reversing command, the predicted overtravel and the safe overtravel envelope are obtained. The sum of the safety clearance and the safety overtravel envelope is determined as the physical target reversing distance. When the physical target reversing distance is greater than the current reversing command distance, the reversing command distance of the next co-directional stroke is directly increased. When the physical target reversing distance is less than or equal to the current reversing command distance, the reversing command distance of the next co-directional stroke is decreased by the step length not exceeding the release distance.

2. The method for pressurization adaptive commutation control of a hot pressing forming gas supply system according to claim 1, characterized in that, The end distance is according to Determined; among them, For the displacement of the filter piston, For the coordinates of the target machine end, The end direction coefficient, For the target mechanical end index, and Pick or , Indicates the proximal end. Indicates the remote end, , , , , To effectively calibrate the travel distance, This represents the distance between the ends.

3. The method for pressurization adaptive reversing control of a hot-pressing gas supply system according to claim 1, characterized in that, The determination of the reverse confirmation event includes: A reverse confirmation event is generated when the sign of the piston movement speed of the target hydraulically driven reciprocating compression cylinder is opposite to the sign of the forward movement direction, the absolute value of the piston movement speed of the target hydraulically driven reciprocating compression cylinder is greater than the reverse confirmation speed threshold, and the preset number of reverse confirmation samplings is maintained.

4. The method for pressurization adaptive commutation control of a hot-pressing gas supply system according to claim 3, characterized in that, The determination of the actual steering clearance, measured overtravel, steering response delay time, and representative value of stroke piston deceleration based on the reverse confirmation event after the hydraulic reversing command output includes: The difference between the reversing command distance and the actual steering clearance is determined as the measured overtravel; the sampling time at which the actual steering clearance is first reached between the reversing command time and the reverse confirmation event is determined as the actual reverse sampling time; the last sampling time at which the absolute value of the piston movement speed of the target hydraulically driven reciprocating compression cylinder reaches its maximum value between the reversing command time and the actual reverse sampling time is determined as the deceleration start sampling time; the difference between the timestamp corresponding to the deceleration start sampling time and the reversing command time is determined as the reversing response delay time; and the median of the local piston deceleration between the deceleration start sampling time and the actual reverse sampling time is determined as the representative value of the stroke piston deceleration. The local piston deceleration characterizes the degree of speed attenuation of the target hydraulically driven reciprocating compression cylinder piston during the deceleration stage after reversing between adjacent sampling times.

5. The method for pressurization adaptive commutation control of a hot-press forming gas supply system according to claim 4, characterized in that, The determination of the predicted overrange includes: For any target mechanical end and effective stroke, the predicted overtravel is calculated according to... Determined; among them, To predict overtravel, This represents the absolute value of the local piston velocity before the reversing command. This is the upper bound of the commutation response delay time. This is the lower bound of piston deceleration.

6. The method for pressurization adaptive commutation control of a hot pressing forming gas supply system according to claim 5, characterized in that, The determination of the safe overrange envelope includes: ;in, For safe overrange envelope, To predict overtravel, To measure the overrange upper envelope, The maximum absolute error in displacement difference measurement. This represents the absolute value of the local piston velocity before the reversing command. The sampling period is denoted by 'max', which indicates taking a larger value.

7. The method for pressurization adaptive commutation control of a hot pressing molding gas supply system according to claim 6, characterized in that, When the physical target reversing distance is greater than the current reversing command distance, the ratio of the physical target reversing distance to the nominal resolution of the piston displacement sensor is rounded up, and the product of the rounded result and the nominal resolution is determined as the reversing command distance for the next co-directional stroke.

8. The method for pressurization adaptive commutation control of a hot pressing forming gas supply system according to claim 6, characterized in that, When the physical target reversing distance is less than or equal to the current reversing command distance, the difference between the current reversing command distance and the physical target reversing distance is determined as the release distance. The maximum departure distance not greater than the release distance is selected from the ordered departure distance set corresponding to the target mechanical end, and the difference between the current reversing command distance and the maximum departure distance is determined as the reversing command distance for the next co-directional stroke. When there is no departure distance not greater than the release distance, the reversing command distance for the next co-directional stroke remains unchanged.

9. The method for pressurization adaptive commutation control of a hot pressing molding gas supply system according to claim 1, characterized in that, After initial commissioning, recalibration of the piston displacement sensor, or replacement of the hydraulic directional valve, perform no less than five low-speed no-load test runs with the proportional valve opening at 20%. Record the maximum directional response delay time, the minimum stroke piston deceleration representative value, and the maximum measured overtravel during the low-speed no-load test runs into the corresponding cyclic arrays for the near and far ends: the cyclic array for the directional response delay time, the cyclic array for the stroke piston deceleration representative value, and the cyclic array for the measured overtravel.

10. The method for pressurization adaptive commutation control of a hot pressing forming gas supply system according to claim 1, characterized in that, The method further includes: The rising edges of the proximal cylinder collision indicator and the distal cylinder collision indicator are detected separately, and each rising edge is recorded as a corresponding cylinder collision event. When the distance between the proximal and distal ends is less than 0.1 mm, the proximal cylinder collision indicator is set, and when the distance between the distal and distal ends is less than 0.1 mm, the distal cylinder collision indicator is set. When the cylinder collision indicator lasts for 5 seconds, a stall alarm is output. When the cumulative number of cylinder collision events reaches 3 within 20 seconds, a cylinder collision alarm is output, and when the cumulative number reaches 5, an interlock shutdown status is output.

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