A cross arm production process

Abstract

The present application relates to the technical field of power hardware processing and manufacturing, and particularly relates to a cross arm production process. The process comprises: after a fluid-incompressible pressure-maintaining rigid boundary is constructed by pressing a main hydraulic cylinder, starting a microseismic device to directionally inject high-frequency mechanical microseismic kinetic energy into the cross arm; synchronously extracting a back pressure feedback value in a sealed loop and monitoring a dynamic attenuation slope thereof in real time; when the slope is detected to be flat and to be in an attenuation stagnation of internal stress release, under a timing safety interlock protection mechanism for executing confirmation of mechanical wave calming, triggering a high-frequency electrically-controlled proportional overflow valve to execute millisecond-level transient micro-pressure relief and extremely fast pressure reconstruction, so as to provide a transient volume yielding space for metal lattice rearrangement; and finally completing final state confirmation when the absolute value of the back pressure is stabilized at a zero rebound threshold. The present application can solve or at least alleviate the secondary rebound problem caused by lattice distortion residual strain energy accumulation in the forming of thick-walled metal components, and improve the production quality of the cross arm.

Description

Technical Field

[0001] This invention relates to the field of power fittings processing and manufacturing technology, and in particular to a crossarm production process. Background Technology

[0002] In the large-scale construction of power transmission and communication network infrastructure, crossarms, as core load-bearing components of transmission towers and communication base stations, directly affect the uniformity of load distribution and mechanical stability of the entire tower structure during long-term service due to their manufacturing precision, especially macroscopic straightness. With the development of ultra-high voltage power transmission and highly integrated communication base station technologies, higher requirements have been placed on the mechanical load-bearing strength of components, leading to the increasingly widespread application of large-size, low-alloy, high-strength, thick-walled metal crossarms. However, after being subjected to external heavy loads and undergoing plastic bending or leveling, thick-walled metal components inevitably experience grain slip and dislocation multiplication within the material, resulting in a large number of dislocation pile-ups at grain boundaries and a high-density residual stress field within the crystal lattice (mainly manifested as macroscopic compressive stress and microscopic lattice distortion potential energy).

[0003] Currently, the straightening process for thick-walled crossarms mainly relies on heavy-duty hydraulic forming equipment. The industry's conventional process path mostly employs a one-way physical processing procedure of "high-pressure forced bending correction - static pressure holding - force release." For example, patents with announcement number CN114193048B and publication number CN120663082A primarily improve the crossarm's interlocking assembly structure mold, material proportions, and heat treatment processes. However, these existing technologies still struggle to solve the problem of "secondary springback (i.e., creep springback)" after the components leave the factory when dealing with the straightening of large-size, thick-walled crossarms. The fundamental material mechanics reason is that the static pressure holding of the heavy-duty hydraulic cylinder only forces the component to maintain a straight configuration at the macroscopic geometric level through strong mechanical boundaries; however, at the microscopic material structure scale, the dislocation network inside the metal, under high stress, does not obtain the geometric allowance necessary for slippage, untangling, and recombination. Due to the external absolute rigidity of the geometric constraints established by the hydraulic system, these distorted potentials cannot undergo substantial physical dissipation; once the load is removed from the cylinder, the residual elastoplastic deformation potential energy will inevitably drive the crossarm to elastically recover, causing the macroscopic dimensions to deviate from the target tolerance zone.

[0004] To address the aforementioned problem of internal stress accumulation, the industry has attempted to introduce vibration aging (VSR) technology, which involves applying high-frequency alternating mechanical vibrations to a workpiece under pressure to promote lattice slip and assist in stress relief. However, under traditional heavy-duty hydraulic absolute pressure-holding conditions, directly superimposing mechanical vibrations presents significant conflicts between fluid dynamics and rigid body dynamics: on the one hand, the hydraulic oil enclosed in the rodless chamber of the hydraulic cylinder has an extremely high bulk modulus, exhibiting essentially incompressible physical properties, and the piston rod is rigidly locked. This absolute fluid rigidity boundary greatly restricts the space required for the metal lattice to undergo microscopic slippage due to alternating stress excitation, resulting in the inability of the input mechanical kinetic energy to be effectively converted into plastic energy dissipation through lattice rearrangement, and the release of internal stress easily stagnates.

[0005] On the other hand, if hydraulic valves are directly opened to relieve pressure during high-frequency mechanical vibration in order to provide deformation clearance space for the crystal lattice, the mechanical vibration cannot stop immediately upon cutting off the control level due to the inherent physical rotational inertia of the mechanical moving parts such as the eccentric rotating mass of the exciter. At this time, the residual high-frequency alternating mechanical stress wave is highly susceptible to energy interference and dynamic coupling with the instantaneously depressurized high-pressure hydraulic fluid, generating high-frequency pressure pulsations (i.e., hydraulic water hammer effect) within the closed fluid circuit, which can easily damage pipelines and seals. This high-frequency transient fluid impact can lead to deformation and failure of cylinder piston rod sealing components (such as step seals), or even fatigue rupture of high-pressure pipelines within the core pump and valve system.

[0006] In summary, how to break the absolute rigidity limitation of the hydraulic cylinder's pressure holding state on the micro-deformation of metal, while providing the micro-volume relief space required for stress release in a controlled manner, and establishing a reliable safety control sequence to prevent hydraulic water hammer caused by interference between mechanical vibration and fluid unloading actions, and ultimately to deeply eliminate the residual stress of deformation in thick-walled crossbeams, has become a technical problem that engineers in this field urgently need to overcome. Summary of the Invention

[0007] To achieve the above-mentioned objectives, this invention provides a crossarm manufacturing process that aims to solve or at least mitigate the technical problems in the prior art where residual stress causes secondary springback after the thick-walled metal crossarm is formed, and where blindly releasing pressure during auxiliary vibration can easily lead to water hammer effects.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a crossarm production process applied to a crossarm production system, the crossarm production system including a main hydraulic cylinder, a micro-vibration device, a displacement sensor, and a pressure sensor, the process comprising the following steps: S1: Control the main hydraulic cylinder to press down the crossarm. When the displacement sensor detects that the pressing coordinate reaches the preset flat reference coordinate, control the main hydraulic cylinder to stop feeding and close the hydraulic main circuit, and switch to the locked pressure holding state. S2: In the locked and pressure-holding state, the micro-vibration device is activated to apply mechanical micro-vibration to the crossarm. At the same time, the back pressure feedback value excited by the rebound of the residual internal stress of the crossarm in the closed circuit is obtained in real time through the pressure sensor, and the dynamic attenuation slope of the back pressure feedback value is continuously monitored. S3: When it is determined that the dynamic attenuation slope of the back pressure feedback value approaches zero and the absolute value of the back pressure is stable within the set zero rebound threshold range, the internal stress is confirmed to be eliminated, the micro-vibration device is turned off and the locking pressure holding state is released, and the main hydraulic cylinder is controlled to depressurize and lift.

[0009] To further realize the present invention, the following technical solutions may be preferred: Preferably, after establishing the locked and pressure-holding state, the pressure sensor synchronously extracts the initial resistance peak value under the ultimate force in the closed circuit, and the control system uses the initial resistance peak value as the benchmark reference background value for evaluating the attenuation slope of the subsequent back pressure feedback value.

[0010] Preferably, during the application of the mechanical micro-vibration, the control system performs adaptive logic determination based on the dynamic attenuation slope of the back pressure feedback value: If the attenuation slope of the back pressure feedback value shows a continuous decreasing trend, it is determined that the internal lattice recombination is smooth, and the operating state of the micro-vibration device remains unchanged. If the attenuation slope of the back pressure feedback value flattens out to form an attenuation plateau, and the current absolute value of the back pressure is higher than the zero rebound threshold range, it is determined that the space for internal stress release is limited. The control system issues a command to suspend the operation of the micro-vibration device and triggers the execution of the volumetric micro-yield step.

[0011] Preferably, the crossarm production system further includes a proportional relief valve bypassed in the closed circuit; the volumetric micro-yield step includes a transient pressure relief action: A pressure relief opening command with a preset pulse width is sent to the proportional relief valve to release part of the high-pressure hydraulic oil to temporarily reduce the rigidity of the hydraulic circuit, causing the main hydraulic cylinder to retract slightly, providing volume clearance space for the sliding and reorganization of the metal lattice inside the crossarm.

[0012] Preferably, before triggering the transient pressure relief action, a timing-based safety interlock protection mechanism to prevent abnormal coupling between mechanical vibration and fluid is implemented: After sending a command to pause the operation of the micro-vibration device, the control system continuously monitors the root mean square value of acceleration, which characterizes mechanical oscillation. Only after the value drops below the set static noise baseline and the mechanical oscillation is confirmed to have subsided can the control system unlock and issue the opening command for the proportional relief valve.

[0013] Preferably, the volumetric micro-relief step further includes an oil inlet repressurization action closely connected with the transient depressurization action: After maintaining the micro-retraction state for a preset delay window period, the proportional relief valve is controlled to close, and the main hydraulic cylinder is instructed to perform oil inlet volume compensation until the force balance boundary is re-established and the lock-up pressure holding state is reconstructed again; at this time, the reconstructed back pressure peak value in the closed circuit is lower than the initial resistance peak value.

[0014] Preferably, after completing the oil inlet repressurization action, the alternating cycle control logic is executed: The control system exits the volumetric micro-yield step, restarts the micro-vibration device to restore mechanical micro-vibration, and constructs an alternating control cycle of "micro-vibration pressure reduction - slope stagnation detection - vibration stop interlock - pressure relief yield - oil inlet repressurization - micro-vibration recovery" within the system.

[0015] Preferably, in step S3, before releasing the locked pressure-holding state, a final state verification action is further included: When multiple consecutive sampling cycles confirm that the back pressure feedback value is within the zero rebound threshold range and there is no abnormal back pressure rebound peak within the set judgment time, the system state is locked and the alternating control cycle is terminated. Then, the return oil channel of the main hydraulic cylinder is opened to perform lifting.

[0016] Preferably, the crossarm production system used in the crossarm production process includes: The main compression forming system, including the main hydraulic cylinder and its driven pressure block, is used to apply a downward pressure load to the crossarm and construct a closed pressure-holding constraint boundary that is incompressible to fluid; The micro-vibration system includes a pneumatic vibrator rigidly mounted on the pressure block, used to input mechanical kinetic energy into the crossarm within the constraint boundary; The dual-parameter feedback system includes a displacement sensor that synchronously monitors the downward pressure coordinate, and a pressure sensor that is bypassed and connected to the closed circuit of the main hydraulic cylinder. The control system is communicatively connected to the main compression molding system, the micro-vibration system, and the dual-parameter feedback system, respectively, and is used to receive and process the back pressure attenuation slope and execute condition triggering and timing interlock scheduling.

[0017] Preferably, the crossarm production system further includes a dynamic fluid compensation system, which includes a proportional relief valve that is bypassed into the closed circuit; the proportional relief valve is controlled by the control system and is used to cooperate with the main hydraulic cylinder to perform transient pressure relief and oil repressurization actions when the system determines that the back pressure decay has entered the decay plateau period.

[0018] The beneficial effects of this invention are: This invention uses a high-sensitivity pressure sensor to monitor the slope of back pressure change in the hydraulic circuit, reflecting the residual internal stress of the crossarm. When stress release is detected to be stalling, it adaptively triggers a proportional relief valve to perform controlled short-term pressure relief. This micro-depression yielding overcomes the rigidity limitations imposed by the incompressibility of the fluid, providing sub-millimeter-level retraction to the main hydraulic cylinder, thus providing the necessary geometric yielding space for the slippage and reorganization of dislocations within the metal material's lattice. Simultaneously, this process introduces a timing interlocking protection mechanism based on acceleration feedback, mandating that the hydraulic valve be opened only after the mechanical vibration of the excitation source has completely subsided. This eliminates the safety risk of hydraulic water hammer caused by the superposition of high-frequency vibration and depressurized fluid from a timing control perspective. This invention effectively eliminates residual stress that could trigger secondary springback while ensuring the crossarm forming accuracy. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the present invention.

[0020] Figure 2 This is the system architecture diagram of the present invention.

[0021] Figure 3 This is a schematic diagram of the back pressure attenuation slope monitoring and fluid-structure interaction transient retreat physical evolution characteristics of the present invention.

[0022] Figure 4 This is a waveform diagram of the anti-hydraulic water hammer timing control based on acceleration feedback according to the present invention.

[0023] Figure 5 This is a histogram comparing the effects of the present invention on the extreme values ​​of microscopic residual stress and macroscopic secondary rebound.

[0024] The attached figures are labeled as follows: 1. Main hydraulic cylinder; 2. Pressure block; 3. High-frequency pneumatic vibrator; 4. High-frequency electronically controlled proportional relief valve; 5. Displacement sensor; 6. Pressure sensor; 7. High-frequency acceleration sensor; 8. Control system; 90. Hydraulic control check valve; 91. Servo hydraulic pump station; 92. Proportional directional valve; 10. Crossbeam. Detailed Implementation

[0025] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] 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.

[0027] In the field of heavy-duty plastic forming of metal crossarm structural components, long, thick-walled low-alloy steel structures, after being subjected to macroscopic compressive bending loads, exhibit highly concentrated and unevenly distributed elastoplastic deformation within their cross-sections. When the external heavy physical constraint load is removed after processing, the dislocation network and residual compressive stress field within the material, which are in a high-stress state, drive the workpiece to undergo elastic deformation recovery, causing the macroscopic geometry of the finished product to deviate from the set target tolerance zone (i.e., creep rebound). The electromechanical-hydraulic multi-physics field collaborative control system and process sequence established in this invention continuously injects high-frequency alternating mechanical vibration within the high-rigidity boundary constructed by a heavy-duty hydraulic circuit. Through rigorous discrete monitoring of the attenuation slope of the fluid back pressure parameter, when a node where internal stress release encounters physical obstruction is identified, a micro-volume pressure relief and closed-loop reset action with anti-interference timing interlock is executed, thereby achieving a stepwise physical dissipation of deep metal residual internal stress and improving the production quality of crossarms. The specific technical solution is as follows: Example 1 Combination Figure 2 As shown, this embodiment discloses a thick-walled crossbeam production system, whose physical system encompasses a main compression molding system, a micro-vibration system, a dynamic fluid compensation system, a multi-parameter sensing feedback system, and a low-level control system. Each subsystem forms a complete closed-loop network at the electromechanical-hydraulic control and sensor data interaction level.

[0028] The main compression forming system outputs a compressive forming thrust that overcomes the yield strength of thick-walled metal materials. After the workpiece reaches the set target flatness, it constructs an absolute fluid pressure-holding constraint boundary that restricts the 10 macroscopic displacement degrees of freedom of the crossarm. The heavy-duty frame of the system is constructed from low-alloy high-strength structural steel plates welded together, with grid-like reinforcing ribs arranged at key stress nodes. After overall welding, it undergoes overall heat aging annealing treatment to eliminate the welding internal stress of the frame body. A large-diameter double-acting main hydraulic cylinder 1 is vertically fixed on the top of the frame. The flange at the lower end of the piston rod of the main hydraulic cylinder 1 is connected to a conformal pressure block 2 for dispersing contact stress. The fluid power of the main hydraulic cylinder 1 is provided by a servo hydraulic pump station 91 directly driven by a servo motor. A large-diameter proportional directional valve 92 and a two-way cartridge-type hydraulic control check valve 90 are connected in series on the high-pressure oil inlet main circuit of its rodless chamber. When the main hydraulic cylinder 1 is pressed down to the position and the control system issues a command to close the hydraulic control check valve 90, the hydraulic oil in the rodless chamber of the main hydraulic cylinder 1 is strictly isolated in a sealed metal pipeline and cylinder body. Based on the fact that petroleum-based hydraulic oil has a very large bulk elastic modulus at room temperature and exhibits the physical property of being substantially incompressible, the sealed high-pressure oil column is transformed into a mechanical support medium with extremely high rigidity, causing the piston rod of the main hydraulic cylinder 1 to completely lose its axial retraction ability, thereby forcibly locking the pressure block 2 on a specific absolute spatial physical coordinate plane.

[0029] The micro-vibration system is used to emit high-frequency alternating stress waves into the deep layers of the metallic matrix under macroscopic mechanical conditions where the crossarm 10 is constrained by fluid lock-in and pressure maintenance. This embodiment uses a high-frequency pneumatic vibrator 3 as the kinetic energy execution terminal. To ensure energy transfer efficiency, the vibrator 3 eliminates the need for rubber damping pads and is directly and rigidly mounted on the non-stressed side wall of the pressure block 2 using high-strength tensile fasteners. A high-speed two-position three-way electromagnetic air valve is configured on the air inlet circuit of the vibrator. When the high-speed eccentric rotor inside the pneumatic vibrator 3 rotates, it generates continuous high-frequency alternating mechanical vibration waves. These vibration waves are transmitted through the rigid pressure block 2 into the interior of the crossarm 10, inducing a misalignment and rearrangement of the crystal structure.

[0030] Specifically, the dynamic fluid compensation system is configured as a transient controlled pressure reduction module that removes the absolute rigidity of the system fluid boundaries. Its core fluid actuator is a high-frequency electronically controlled proportional relief valve 4. For example... Figure 2As shown in the hydraulic circuit topology, the inlet of the proportional relief valve 4 is independently bypassed and connected to the locked high-pressure oil circuit between the rodless chamber of the main hydraulic cylinder 1 and the hydraulically controlled check valve 90, while the outlet is directly connected to the low-pressure, normal-pressure return oil tank. This valve has zero leakage in its normally closed state and does not affect the pressure-holding stiffness of the main circuit. When it receives a millisecond-level analog pulse drive signal from the control system 8, its pilot stage responds instantaneously under the drive of the voice coil motor. The main valve core overcomes the system's high pressure and opens a very small flow cross-sectional area, discharging a set amount of hydraulic oil into the oil tank. This brief oil discharge action releases the isovolute state of the sealed pipeline, causing the main hydraulic cylinder 1 to produce controlled sub-millimeter-level axial retraction under the action of the upward counter-pushing force of the crossarm.

[0031] A multi-parameter feedback system is used to establish a high-frequency data transmission link between the macroscopic kinematic parameters of heavy equipment and the microscopic mechanical state of its components. The housing of the magnetostrictive displacement sensor 5 is mounted parallel to the outer cylinder side of the main hydraulic cylinder 1, continuously outputting the absolute spatial position coordinates of the pressure block 2 to the control system 8. A high-response-frequency sputtered thin-film piezoresistive pressure sensor 6 is mounted on the pressure measuring valve block on the side wall of the rodless chamber, accurately capturing the fluid pressure (i.e., the back pressure feedback value) that nonlinearly increases within the closed hydraulic oil cavity due to the upward push of residual deformation stress inside the crossarm. A high-frequency piezoelectric accelerometer 7 is bonded to the surface of the pressure block 2, acquiring the acceleration amplitude signal of the mechanical vibration state in real time.

[0032] The analog current / voltage signals and digital pulse signals from the aforementioned sensors are uniformly and rapidly fed into the underlying control system 8. Control system 8 employs an industrial programmable logic controller (PLC) equipped with a high-speed floating-point unit (FPU). The system memory contains dedicated digital signal processing routines that effectively suppress the background high-frequency white noise caused by hydraulic pump source pulsation using a first-order low-pass filtering algorithm. Based on the least squares algorithm, it performs continuous calculus-integral linear fitting on discrete pressure data points within a sliding window, calculates and outputs the back pressure attenuation slope in real time, and then drives the underlying state machine program to coordinate the scheduling of various hydraulic and pneumatic actuators based on preset logic thresholds.

[0033] Example 2 Based on the aforementioned electromechanical-hydraulic hardware closed-loop control architecture, the crossarm production process of this invention abandons the traditional fixed-time-axis open-loop control and adopts a state machine control network driven by multi-sensor parameter threshold adaptive control. Combined with... Figure 1 The flowchart and process sequence specifically include the following steps: S1: Downward addressing positioning and establishment of absolute lock-in pressure holding; specific operation is as follows: The control system 8 outputs analog drive level to the servo hydraulic pump station 91 and the proportional directional valve 92. High-pressure hydraulic oil enters the rodless chamber of the main hydraulic cylinder 1, pushing the pressure block 2 downward to squeeze the crossarm 10, causing it to undergo macroscopic plastic bending and forming. The control system 8 internally runs a PID position closed-loop control algorithm, continuously scanning the absolute position coordinates fed back by the displacement sensor 5 at high speed. When the piston rod extends and accurately reaches the preset target flat reference coordinate (i.e., the design target tolerance zero position to ensure the flatness of the crossarm at the factory), the control system cuts off the oil inlet drive command and simultaneously controls the main valve core of the two-way cartridge hydraulic control check valve 90 to close. At this time, the sealed oil medium cuts off the fluid interaction in the main circuit, establishing the lock-in pressure holding state.

[0034] At the instant the crossarm 10 is forcibly flattened, the large amount of elastic potential energy accumulated inside by plastic bending is converted into an upward mechanical reverse thrust, causing a sharp nonlinear increase in the back pressure of the closed fluid in the rodless cavity. Pressure sensor 6 extracts the extreme value when the system pressure curve reaches a stable steady state and stores it in the system register as the initial resistance peak value in this processing cycle, which is used as the physical reference background for subsequent evaluation of the internal stress relief effect.

[0035] S2: Dynamic monitoring of alternating dynamic energy injection and back pressure attenuation slope; specific operation is as follows: After establishing an absolute pressure-holding safety condition, the control system 8 outputs a conducting level to activate the electromagnetic valve of the pneumatic vibrator 3, introducing alternating mechanical vibration waves into the deep matrix inside the crossarm 10 at high frequency. The high-frequency alternating stress field deeply intervenes in the dislocation pile-up region inside the metal caused by plastic deformation, reducing the effective yield limit of the local stress concentration area, and causing the metal lattice to produce local microscopic plastic slip and unentanglement, thereby gradually converting the accumulated distortion potential energy into heat energy dissipation.

[0036] During this dissipation process, the control system 8 continuously acquires the back pressure feedback value from the pressure sensor 6 at a kilohertz sampling rate, and within a sliding time window set within the algorithm (such as a dynamic data array of 0.5 seconds to 1.0 seconds), it real-time fits and monitors the dynamic attenuation slope of the back pressure curve. If the monitoring calculation shows that the back pressure attenuation slope remains a significantly negative real number, it is determined that the internal stress of the component is in a smooth release state, and the system maintains the excitation air valve in the open state.

[0037] S3: Physical state foolproof interlock and controlled volume micro-pressure relief reconstruction mechanism; the specific operation is as follows: When the underlying control algorithm detects that the absolute value of the back pressure attenuation slope gradually converges or even falls below the set stagnation threshold (for example, within a continuous 1.5-second judgment period, the absolute value of the slope is <0.05MPa / s, and the pressure evolution curve shows an attenuation plateau period), and at the same time, the absolute value of the back pressure in the current pressure feedback loop is still significantly higher than the expected safe zero rebound range (such as higher than the 1.5-3.0MPa range), the system logic triggers a judgment: due to the external absolute rigid geometric boundary constructed by the completely incompressible hydraulic oil volume, the internal metal material of the crossarm has lost the micro-geometric deformation space for further dislocation and rearrangement of the lattice, and the stress attenuation and release process has fallen into severe physical stagnation. At this time, the control system 8 immediately sends a level interrupt signal, cuts off the air supply of the pneumatic vibrator, and forcibly enters the core volume micro-yield intervention step.

[0038] In practice, the specific steps are as follows: S301: Source inertial isolation timing interlock; specific operation is as follows: To prevent water hammer impact caused by the superposition of mechanical vibration and fluid pressure drop transients in the closed hydraulic pipeline, after issuing the pause micro-vibration command, due to the non-negligible mechanical rotational kinetic energy inertia of the exciter's eccentric rotor, the control system 8 forces the underlying logic to continuously read the feedback signal from the high-frequency acceleration sensor 7. Only when the system monitors that the root mean square value of acceleration (RMS) drops to the system's calibrated static noise baseline (e.g., <0.05g), and objectively confirms that the inertia of the mechanical components has been completely consumed and the vibration has completely subsided, will the control state machine release the dead zone lock of the pilot control stage of the proportional relief valve 4.

[0039] S302: Minor Pressure Relief and Coordinate Closed-Loop Resetting; Specific operation is as follows: After the foolproof interlock is released, the control system 8 sends a millisecond-level drive level pulse (e.g., pulse width 20-80 milliseconds) to the high-frequency electronically controlled proportional relief valve 4, which has been rigorously tuned through process experiments. The main valve core of the proportional relief valve momentarily opens to discharge a very small amount of hydraulic oil of a set volume, causing the high rigidity of the hydraulic closed loop to be temporarily released. Under the strong counter-push action of the crossarm, the main hydraulic cylinder 1 produces a controlled sub-millimeter-level micro-retraction. This macroscopically controlled relief provides the key microscopic deformation geometry conditions for the constrained dislocation network inside the crossarm to spontaneously complete the unbinding and reorganization sliding, and removes the physical hindrance state of stress attenuation.

[0040] After maintaining the micro-retraction and yielding state for the preset sliding delay, the overflow valve closes. At this point, the critical re-setting stage for ensuring finished product tolerances begins: Control system 8 instructs the hydraulic pump station to output power again, perform oil inlet volume compensation, and, relying on the micron-level closed-loop value of displacement sensor 5, forcibly drive the pressure block 2 to re-descend and precisely locate it at the "flat reference coordinates" recorded in step S1. After flattening it to its original position, the hydraulic control check valve is closed again to reconstruct the locked pressure-holding state, thereby ensuring the workpiece's accuracy.

[0041] During this process, a large amount of residual stress inside the crossarm is actually converted into irreversible plastic slip work of the micro-lattice and physically dissipated during the micro-distance yielding period. At this time, the peak value of the back pressure re-established under the target coordinates in the loop will experience a step drop, substantially lower than the resistance peak value recorded at the beginning of this cycle. After the coordinate and pressure state reconstruction is completed, the system reconnects the air source to start the pneumatic vibrator 3, and the logic jumps back to step S2, constructing an alternating nested control network of "monitoring-blockage judgment-yielding-closed-loop reset-re-vibration".

[0042] S4: Final state safety confirmation of internal stress and lifting unloading of material; the specific operation is as follows: After several rounds of intervention cycles automatically executed by the equipment, the internal stress of the material is peeled off and dissipated step by step. When the control system 8 calculates and determines that the attenuation slope of the back pressure fed back by the pressure sensor 6 is stable and close to zero within the set final safety verification time (such as a judgment period of 3-5 seconds of continuous sampling), and the absolute value of the back pressure has fallen and is stably suspended within the calibrated zero rebound safety threshold range, and no abnormal rebound fluctuation of back pressure caused by the sudden change of deep lattice viscous resistance is detected, the system confirms that the internal stress in the component that caused macroscopic secondary rebound has been basically physically eliminated.

[0043] At this point, control system 8 triggers the final state completion flag, terminating the state machine judgment loop. The mechanical vibration air source and hydraulic volume compensation logic channel are permanently cut off. An instruction is given to open the low-pressure, large-diameter return oil valve of the rodless chamber of the main hydraulic cylinder to perform rapid unloading. The piston rod rises at full speed to reset, and the crossarm workpiece is safely removed from the mold processing area.

[0044] Example 3: Engineering Performance Testing and Comparison Verification of Underlying Control Principles and Data To objectively and quantitatively evaluate the actual technical effectiveness of this multi-physics field-hydraulic synergistic process in controlling residual stress and suppressing secondary springback, the testing team selected Q420 low-alloy high-strength thick-walled angle steel crossarms with identical cross-sectional specifications, material batches, and a length of 5000 mm, and established three sets of control experiment matrices for quantitative analysis.

[0045] The first set of comparative processes: Using industry-standard heavy-duty hydraulic forming equipment for high-load static pressure forced bending and leveling, followed by long-term static absolute pressure holding and direct unloading and part removal; The second set of control processes: mechanical micro-vibration intervention is superimposed throughout the pressure holding process, but conventional rigid absolute pressure holding control logic is executed (i.e., no proportional relief valve micro-volume pressure relief and closed-loop reset steps are implanted in the system). The third verification process: The complete crossarm hydraulic collaborative production system and process disclosed in this invention, which includes back pressure slope calculation monitoring and timing-based error prevention interlocking micro-pressure relief mechanism, is adopted.

[0046] 1. Verification of the timing sequence of physical field anti-interference safety interlocks and the effectiveness of hydraulic water hammer suppression; specifically: Combination Figure 4 The mechanism was deduced by plotting the control waveform diagram of the anti-hydraulic water hammer timing safety interlock theory based on the hardware level. During the second set of equipment debugging experiments, if the control logic lacks closed-loop timing interlock, blindly opening the high-pressure hydraulic valve to perform forced depressurization during the high-frequency application stage of mechanical micro-vibration will cause strong energy interference between the high-speed jet of instantaneous depressurization and the high-frequency mechanical alternating wave. The high-frequency data acquisition card in the system will capture an abnormal hydraulic water hammer shock wave packet with a peak value of over 38MPa that is released instantaneously and rapidly in the closed pipeline. The equipment is accompanied by a violent metallic impact sound. After disassembly and inspection, it was found that the polyurethane composite sealing ring at the end of the main cylinder flange had suffered severe extrusion fatigue damage and even tearing.

[0047] The monitoring records of the third set of control programs of this invention running normally showed the following: Figure 4 The physical field timing isolation characteristics are shown. After the command to cut off the excitation air source control level is issued (upper channel waveform jump), the acceleration RMS value (middle channel waveform) will inevitably have a mechanical attenuation tail region affected by the rotational inertia of the eccentric rotor. At this time, the control bottom state machine of this invention forcibly locks the proportional relief valve drive pulse (lower channel) to a zero potential dead zone state. Only when the DSP calculation confirms that the RMS curve falls within the set static noise floor baseline (safety margin) is the pilot stage of the relief valve physically allowed to output a millisecond-level pulse width pressure relief signal. This non-overlapping timing hard isolation foolproof mechanism cuts off the physical path of coupling between mechanical vibration waves and transient depressurized fluid from the source of control logic. The pressure curve transitions during each pressure relief and oil repressurization stage are extremely smooth and rounded. No high-frequency water hammer peaks exceeding the static design limits of the system are captured throughout the process, ensuring the long-term reliable operation of the heavy servo molding equipment.

[0048] 2. Verification of the back pressure slope characteristic evolution and transient volume yielding dissipation mechanism; specifically: Combination Figure 3The back pressure attenuation slope and the evolution waveform of the physical process of micro-pressure relief are shown in the diagram. In the initial stage of operation using the third group of processes of this invention, after the main cylinder establishes the initial absolute holding pressure, the initial resistance peak stored in the system is approximately 14.5 MPa. After initiating high-frequency mechanical micro-vibration energy intervention, the pressure curve exhibits a step-like decreasing attenuation trend with slight sawtooth fluctuations. Until the back pressure drops to approximately 8.3 MPa, due to the fluid rigid boundary restricting the deformation space of the lattice, the decreasing slope rapidly converges to a horizontal state, and the system is determined to have entered the stress attenuation physical stagnation plateau period.

[0049] After the algorithm accurately captures the plateau period and triggers the high-frequency proportional relief valve to perform millisecond-level pulse micro-pressure relief, the control system pressure curve synchronously captures a highly controlled local unloading U-shaped trough (the depth of which maps the sub-millimeter micro-retraction of the main hydraulic cylinder piston rod). The core mechanism data verification is as follows: After completing the oil inlet volume compensation guided by the displacement sensor closed loop and driving the pressure block to move back to the initially set flat reference displacement coordinate, the pressure evolution curve shows a rapid rise. However, the new back pressure peak after re-establishing pressure balance only rises and falls back to the scale level of about 11.8 MPa, which is lower than the initial high pressure state to the initial high pressure state of 14.5 MPa before pressure reduction. Under the premise that the absolute geometric displacement coordinate (displacement L) of the macroscopic piston rod is completely restored to consistency, the closed fluid pressure (back pressure P) formed by the internal metal elastic force undergoes a substantial step drop. This definitive difference in physical variables proves from the dual underlying logic of solid mechanics and fluid mechanics that the transient, minute geometric retreat space actively created by the system acts on the internal lattice of the metal, substantially activating, transforming, and physically dissipating the high-energy dislocations and elastic residual stresses that were originally stagnant deep within the material.

[0050] 3. Verification of residual stress elimination and macroscopic springback measurement in finished products; specifically: After the three sets of crossbeam molding specimens were completed and processed, they were transferred to a constant temperature workshop and statically placed for 720 hours to ensure that the internal stress redistribution and creep of the components were fully stabilized. Subsequently, the professional testing team used the blind hole method (drilling strain release method) of heavy steel structure industry standard to measure the maximum distribution of residual principal stress on the surface and deep layers of the material in the main load bending section area of ​​each component with high precision; and used a high-precision large coordinate measuring machine or laser tracker to measure the center deflection coordinate drift of each component in an unconstrained free state (i.e., the most critical macroscopic secondary springback index).

[0051] The quantitative test results are summarized as follows: Figure 5 The histogram showing the comparison of measured results is shown below: The first group of specimens (using the traditional heavy-load static pressure holding process) relied solely on the mechanical rigidity of an external large-tonnage hydraulic cylinder for forced pressure holding, completely lacking a physical pathway to induce micro-stress dissipation and release. As a result, the extreme values ​​of residual compressive stress on the surface and inside exceeded 230 MPa. After the external load was removed and the specimens were left to stand, the accumulated enormous deformation potential energy was rapidly released, resulting in a macroscopic secondary creep rebound deflection as high as 4.2 mm. The specimens' straightness tolerances were severely exceeded, rendering them unusable.

[0052] The second set of specimens (using the conventional micro-vibration pressure-holding process), despite the introduction of vibrational kinetic energy, ultimately suffered physical stagnation due to the rigid geometric boundary constraints imposed by the absolutely incompressible physical properties of hydraulic oil, which hindered the dislocation slippage within the metal lattice. The remaining residual tensile stress remained high at approximately 95 MPa, and the final macroscopic center rebound after unloading reached 2.6 mm, failing to meet the stringent factory standards for ultra-high voltage projects.

[0053] In contrast, the experimental results of the third group of thick-walled crossarm specimens processed using the complete electromechanical-hydraulic multi-physics field closed-loop collaborative process disclosed in this application show that the crossarms processed using the process of this application achieve effective dissipation of residual stress at the micro level, and the distribution of macroscopic residual principal stress is more uniform, with the maximum value reduced to less than 45 MPa; correspondingly, the center springback after resting is controlled to less than 0.8 mm, significantly reducing the secondary springback.

[0054] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A crossarm production process, applied to a crossarm production system, the crossarm production system comprising a main hydraulic cylinder (1), a micro-vibration device, a displacement sensor (5), and a pressure sensor (6), characterized in that, The process includes the following steps: S1: Control the main hydraulic cylinder (1) to press down the crossarm (10). When the displacement sensor (5) detects that the pressing coordinate reaches the preset flat reference coordinate, control the main hydraulic cylinder (1) to stop feeding and close the hydraulic main circuit, and switch to the locked pressure holding state. S2: In the locked and pressure-holding state, the micro-vibration device is activated to apply mechanical micro-vibration to the crossarm (10), and at the same time, the back pressure feedback value excited by the rebound of the residual internal stress of the crossarm (10) in the closed circuit is obtained in real time through the pressure sensor (6), and the dynamic attenuation slope of the back pressure feedback value is continuously monitored. S3: When it is determined that the dynamic attenuation slope of the back pressure feedback value approaches zero and the absolute value of the back pressure is stable within the set zero rebound threshold range, the internal stress is confirmed to be eliminated, the micro-vibration device is turned off and the locking pressure holding state is released, and the main hydraulic cylinder (1) is controlled to depressurize and lift.

2. The crossarm manufacturing process according to claim 1, characterized in that, After establishing the locked and pressure-holding state, the pressure sensor (6) synchronously extracts the initial resistance peak value under the ultimate force in the closed circuit, and the control system (8) uses the initial resistance peak value as the benchmark reference background value for evaluating the attenuation slope of the subsequent back pressure feedback value.

3. The crossarm manufacturing process according to claim 1, characterized in that, During the application of the mechanical micro-vibration, the control system (8) performs adaptive logic determination based on the dynamic attenuation slope of the back pressure feedback value: If the attenuation slope of the back pressure feedback value shows a continuous decreasing trend, it is determined that the internal lattice recombination is smooth, and the operating state of the micro-vibration device remains unchanged. If the attenuation slope of the back pressure feedback value flattens out to form an attenuation plateau period, and the current absolute value of the back pressure is higher than the zero rebound threshold range, it is determined that the space for internal stress release is limited. The control system (8) issues an instruction to suspend the operation of the micro-vibration device and triggers the execution of the volumetric micro-yield step.

4. The crossarm manufacturing process according to claim 3, characterized in that, The crossarm production system also includes a proportional relief valve (4) with a bypass connection to the closed circuit; the volumetric micro-yield step includes a transient pressure relief action: Send a pressure relief opening command with a preset pulse width to the proportional relief valve (4) to release part of the high-pressure hydraulic oil to temporarily reduce the rigidity of the hydraulic circuit, so that the main hydraulic cylinder (1) will retract slightly, providing volume clearance space for the sliding and reorganization of the metal lattice inside the crossarm (10).

5. The crossarm manufacturing process according to claim 4, characterized in that, Before triggering the transient pressure relief action, a timing safety interlock protection mechanism to prevent mechanical vibration and abnormal fluid coupling is executed: After sending the instruction to pause the operation of the micro-vibration device, the control system (8) continuously monitors the root mean square value of acceleration that characterizes mechanical oscillation. Only after the value drops below the set static noise baseline and the mechanical oscillation is confirmed to have subsided can the control system unlock and issue the opening instruction of the proportional relief valve (4).

6. The crossarm manufacturing process according to claim 4, characterized in that, The volumetric micro-yield step also includes an oil inlet repressurization action that is closely linked to the transient depressurization action: After the micro-retraction state is maintained for a preset delay window period, the proportional relief valve (4) is controlled to close, and the main hydraulic cylinder (1) is instructed to perform oil inlet volume compensation until the force balance boundary is re-established and the lock-up pressure holding state is reconstructed again; at this time, the reconstructed back pressure peak in the closed circuit is lower than the initial resistance peak.

7. The crossarm manufacturing process according to claim 6, characterized in that, After completing the oil inlet repressurization action, the alternating cycle control logic is executed: The control system (8) exits the volume micro-yield step, restarts the micro-vibration device to restore mechanical micro-vibration, and constructs an alternating control cycle of "micro-vibration pressure reduction - slope stagnation detection - vibration stop interlock - pressure relief yield - oil inlet pressure restoration - micro-vibration recovery" within the system.

8. The crossarm manufacturing process according to claim 1, characterized in that, In step S3, before releasing the locked pressure holding state, a final state verification action is also included: When multiple consecutive sampling cycles confirm that the back pressure feedback value is within the zero rebound threshold range and there is no abnormal back pressure rebound peak within the set judgment time, the system state is locked and the alternating control cycle is terminated. Then, the return oil channel of the main hydraulic cylinder (1) is opened to perform lifting.

9. A crossarm manufacturing process according to any one of claims 1-8, characterized in that, The crossarm production system used in the crossarm production process includes: The main compression forming system includes a main hydraulic cylinder (1) and a pressure block (2) driven by it, for applying a downward pressure load to the crossarm (10) and constructing a fluid-incompressible closed pressure-holding constraint boundary; The micro-vibration system includes a pneumatic vibrator (3) rigidly mounted on the pressure block (2) for inputting mechanical kinetic energy into the crossarm (10) within the constraint boundary; The dual-parameter feedback system includes a displacement sensor (5) that synchronously monitors the downward pressure coordinate, and a pressure sensor (6) that is bypassed and connected to the closed circuit of the main hydraulic cylinder (1). The control system (8) is connected to the main compression molding system, the micro-vibration system and the dual-parameter feedback system respectively, and is used to receive and process the back pressure attenuation slope and perform condition triggering and timing interlocking scheduling.

10. A crossarm manufacturing process according to claim 9, characterized in that, The crossarm production system also includes a dynamic fluid compensation system, which includes a proportional relief valve (4) that is bypassed into the closed circuit. The proportional relief valve (4) is controlled by the control system (8) and is used to cooperate with the main hydraulic cylinder (1) to perform transient pressure relief and oil repressurization actions when the system determines that the back pressure decay has fallen into the decay plateau period.

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