Steel rail flash welding control method and device based on welding microscopic state judgment

Abstract

The invention provides a steel rail flash welding control method and device based on welding microscopic state judgment, and belongs to the technical field of steel rail welding. The steel rail flash welding control method comprises the steps that in the flash welding process, voltage and current sampling is conducted on a welding primary loop, sampling data are obtained, and the sampling data are cut off according to the half cycle of alternating current; calculating the current signal derivative and power in each half cycle based on the truncated sampling data; according to the current signal derivative and the power, the welding state of the corresponding half cycle is judged; and welding process parameters are regulated and controlled according to the welding state. Heat input and burning speed control in the welding process are directly associated by taking the microscopic state of the welding end face as a control reference and combining a hardware system and an algorithm. Automatic dynamic adjustment of all process stages is achieved, the adjustment time of welding process parameters is shortened, and the production efficiency is improved. And meanwhile, parameter setting and operation processes can be simplified, and the operation difficulty is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of rail welding, and in particular to a rail flash welding control method and device based on welding micro-state discrimination. Background Art

[0002] Rail flash welding uses electrodes to heat the contact points of the two rail end faces to form a liquid metal lintel and flash continuously. When the flash heating reaches an appropriate temperature, a top forging force is quickly applied to squeeze the rail end faces against each other, causing intense plastic deformation in the welding area and cross-crystallization of the bonding surfaces to form a welded joint.

[0003] In the field of rail flash welding, AC flash welders are widely used in on-site rail welding construction due to their simple and reliable electrical structure. Traditional AC flash welders use current threshold as the key control parameter of the welding process. The most basic process control method is as follows:

[0004] At different stages of rail flash welding, different jaw feed speeds are preset. The current value is collected in real time through the current sampling module, and the feed speed is adjusted in real time based on the current value. When the current value is large, the jaw is controlled to move back; when the current value is small, the jaw is controlled to move forward.

[0005] The above-mentioned process control method has two insurmountable technical defects. First, during the welding process, the heating state and the burning state of the welding are actually in an unstable state, and the heat input of the welding is poorly controllable. Secondly, due to the changes in the end surface parameter state during the welding process, the current threshold to achieve the target is changing and difficult to accurately measure, which is why traditional processes often use multi-stage current settings. Taking the pulsation stage as an example, in order to adjust the heating efficiency of the pulsation stage, it is necessary to synchronously adjust multiple indirect parameters such as welding voltage, welding current threshold, and feed speed, and it is not convenient to directly modify the heating efficiency.

[0006] In view of this, the inventor, based on many years of production design experience in this field and related fields, has designed a rail flash welding control method and device based on welding microstate identification after repeated experiments, in order to solve the problems existing in the prior art. Summary of the invention

[0007] The object of the present invention is to provide a rail flash welding control method and device based on welding micro-state discrimination, which can accurately control the rail consumption during the flash welding process.

[0008] In order to achieve the above-mentioned object of the invention, the present invention proposes a rail flash welding control method based on welding micro-state discrimination, wherein the rail flash welding control method comprises:

[0009] During the flash welding process, the voltage and current of the welding primary circuit are sampled and the sampling data is obtained, and the sampling data is truncated according to the half cycle of the alternating current;

[0010] Based on the truncated sampled data, the current signal derivative and power in each half cycle are calculated;

[0011] Determine the welding state of the corresponding half cycle according to the current signal derivative and power;

[0012] The welding process parameters of the rail flash welding are regulated according to the welding state.

[0013] The present invention also proposes a rail flash welding control device based on welding micro-state discrimination, wherein the flash welding control device comprises:

[0014] A voltage sensor is arranged on the primary welding circuit, and the voltage sensor samples the voltage of the primary welding circuit and obtains voltage sampling data;

[0015] A current sensor is arranged on the primary welding circuit, and the current sensor samples the current of the primary welding circuit and obtains current sampling data;

[0016] A programmable controller determines the state of the welding primary circuit according to the voltage sampling data and the current sampling data, and controls the welding process according to the state of the welding primary circuit in combination with the set process parameters;

[0017] The frame is used to clamp and center the rails to be welded. The movement of the frame is controlled by the process parameters.

[0018] Compared with the prior art, the present invention has the following characteristics and advantages:

[0019] The present invention proposes a rail flash welding control method and device based on welding micro-state discrimination, which divides the welding process into multiple welding stages, collects voltage and current signals during the welding process, identifies the micro-state of the welding end face in real time, and then judges the current welding state based on the micro-state. The current welding state can be used as a threshold to control the jaw movement, so as to more accurately control the movement of each stage according to a preset state percentage.

[0020] The present invention proposes a rail flash welding control method and device based on welding micro-state discrimination. The micro-state of the welding end face is used as the control reference, combined with the hardware system and algorithm, directly linking the heat input and burning speed control of the welding process, realizing the automatic dynamic adjustment of each process stage, reducing the adjustment time of welding process parameters, and improving production efficiency. At the same time, it can also simplify parameter settings and operation procedures, reducing the difficulty of operation.

[0021] The present invention proposes a rail flash welding control method and device based on welding microstate discrimination, which significantly improves the controllability and stability of the welding process, reduces welding quality fluctuations caused by current threshold setting deviations or experience dependence, simplifies the complexity of parameter setting, realizes automatic dynamic adjustment of each process stage, improves the uniformity of welding joint quality and the precision of heat input control, and enhances adaptability to complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0023] Figure 1 It is a schematic flow chart of the rail flash welding control method of the present invention;

[0024] Figure 2 It is a schematic diagram of the system structure of an application example of the present invention;

[0025] Figure 3 A schematic diagram of voltage and current curves of a short-circuit type in the welding process of the present invention;

[0026] Figure 4 A schematic diagram of voltage and current curves of the open circuit type in the welding process of the present invention;

[0027] Figure 5 A schematic diagram of voltage and current curves of a single beam blasting type in the welding process of the present invention;

[0028] Figure 6 A schematic diagram of voltage and current curves of a multi-beam explosion type in the welding process of the present invention;

[0029] Figure 7 It is a schematic diagram of the electrical signal in the pulsation stage of the present invention. DETAILED DESCRIPTION

[0030] The details of the present invention can be more clearly understood with reference to the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only used for the purpose of explaining the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should all be considered to belong to the scope of the present invention.

[0031] The present invention proposes a rail flash welding control method based on welding micro-state discrimination, wherein Figure 1 As shown, the rail flash welding control method includes:

[0032] During the flash welding process, the voltage and current of the welding primary circuit are sampled and the sampling data is obtained, and the sampling data is truncated according to the half cycle of the alternating current;

[0033] Based on the truncated sampled data, the current signal derivative and power in each half cycle are calculated;

[0034] Determine the welding state of the corresponding half cycle according to the current signal derivative and power;

[0035] The welding process parameters of rail flash welding are adjusted according to the welding status.

[0036] The present invention proposes a rail flash welding control method based on welding microstate discrimination, which collects voltage and current signals in the welding process, cuts the sampled data according to the half cycle of alternating current, calculates the current signal derivative and power in each half cycle, and judges the welding state of the welding end face in real time according to these data, and controls the welding process parameters of the rail flash welding accordingly, thereby realizing real-time monitoring and dynamic adjustment of the welding process, improving the stability and controllability of the rail flash welding process, reducing welding quality fluctuations caused by current threshold setting deviation or experience dependence, simplifying the complexity of parameter setting, realizing automatic dynamic adjustment of each process stage, improving the uniformity of welding joint quality and the precision of heat input control, and enhancing the adaptability to complex working conditions.

[0037] According to the rail flash welding control method based on welding micro-state discrimination proposed by the present invention, the rail flash welding process is divided into multiple welding stages, and the action of the jaws is controlled according to the current threshold in each stage. After the current welding state is microscopically judged according to the current signal derivative and power, the state can be used as a threshold to control the action of the jaws, and the action of each stage can be controlled more accurately according to the preset state percentage, ensuring that each stage is accurately switched according to the welding requirements, avoiding the hysteresis of the traditional current control method.

[0038] The present invention proposes a rail flash welding control device based on welding micro-state discrimination, wherein Figure 2 As shown, the rail flash welding control device includes:

[0039] A voltage sensor is arranged on the primary welding circuit, and the voltage sensor samples the voltage of the primary welding circuit and obtains voltage sampling data;

[0040] A current sensor is arranged on the primary welding circuit, and the current sensor samples the current of the primary welding circuit and obtains current sampling data;

[0041] A programmable controller determines the state of the welding primary circuit according to the voltage sampling data and the current sampling data, and controls the welding process according to the state of the welding primary circuit in combination with the set process parameters;

[0042] The frame is used to clamp and center the rails to be welded. The movement of the frame is controlled by the process parameters.

[0043] The present invention proposes a rail flash welding control device based on welding micro-state discrimination, which collects the electrical signals of the welding circuit in real time through high-precision voltage and current sensors, providing a stable and reliable data basis for micro-state identification; the programmable controller dynamically discriminates the short circuit, open circuit and lintel explosion states based on electrical signal analysis, and generates process control instructions that match the current end face state; the frame accurately adjusts the jaw feed speed and pressure through a high-speed response action execution unit, forming a closed-loop system from state perception to dynamic control, ensuring the uniformity of heat input and burning efficiency during the welding process. The synergistic effect of the various modules of the rail flash welding control device of the present invention converts the abstract algorithm of micro-state discrimination into physically implementable control logic, significantly improving the real-time adjustment of welding parameters and the control accuracy of the end face burning amount, thereby providing a hardware architecture guarantee for the precise control implementation of the rail flash welding control method of the present invention.

[0044] In an optional embodiment of the present invention, the set of sampling data of the truncated current is {…, (Ta, Ia), …, (Tb, Ib), …}; the derivative is calculated in real time, and the calculation formula of the derivative I' at the current moment is: I'= (Ib-Ia) / (Tb-Ta); where T is the sampling moment and I is the current at that moment.

[0045] In an optional example of this embodiment, a and b represent two adjacent sampling points, and the slope of the two points can be calculated by the above calculation formula. For example, there is a set of current data at each moment {..., (1.5ms, 10A), (2ms, 13A), (2.5ms, 40A),...}, then two current signal derivatives can be calculated, (13-10) / (2-1.5) = 6A / ms; the second point 27 / 0.5 = 54A / ms. Similarly, if the time and current curves are drawn, if the time and current curves have N points, N-1 current signal derivatives can be calculated. If the derivative curve jumps, for example, the current signal derivative changes from 6 to 54, it indicates that the welding current has a sudden change, that is, the beam explosion has occurred. If it is a short circuit or an open circuit, the derivative curve will change very slowly.

[0046] In order to realize the rail flash welding control method proposed by the present invention, the voltage and current of the welding circuit are sampled, which is the basis for realizing the welding state judgment. Furthermore, through a set of algorithms, these electrical signals are automatically calculated and analyzed to realize the judgment of the welding end surface state of the welding process, and then realize the dynamic adjustment of the welding process.

[0047] Specifically, by synchronously sampling the voltage and current signals, the current welding state can be judged based on the sampled data in the half cycle. In the half cycle, when the voltage signal rises to the threshold value Vmin, it is considered that the thyristor in the half cycle is in the on state, and from this moment on, the current signal derivative I' in the half cycle is calculated. It should be noted that the above calculation method is not unique, and other calculation methods can be selected according to actual needs. By calculating the derivative of the current signal, the microscopic state in the welding process can be accurately judged, thereby achieving precise control of the welding process.

[0048] In an optional embodiment of the present invention, the power calculation formula is:

[0049]

[0050] Wherein, u(k) is the voltage sequence, and u(k)={U1,…Un}; i(k) is the current sequence, and i(k)={I1,…In}.

[0051] The power P of the entire half cycle is calculated by the power calculation formula for auxiliary judgment. Specifically, by synchronously sampling the voltage and current signals, the voltage sequence u(k) and the current sequence i(k) are obtained, where k represents the serial number of the sampling point and n represents the total number of sampling points in the half cycle. The voltage value u(k) of each sampling point is multiplied by the corresponding current value i(k) to obtain the instantaneous power value, and then all instantaneous power values ​​are summed and averaged to obtain the average power P of the entire half cycle. Correspondingly, the current signal derivative I is the current derivative curve of the half cycle. By introducing the power calculation formula, accurate monitoring and auxiliary judgment of the welding process are achieved, which provides important auxiliary information for the judgment of the welding state, improves the stability and controllability of the welding process, and reduces the welding quality fluctuation caused by the current threshold setting deviation or experience dependence.

[0052] In an optional embodiment of the present invention, when the power P is less than the first preset power Pa, the half-cycle is judged to be in an open circuit state; when the current signal derivative I is within the preset range [Ia', Ib'] and the power P is greater than the second preset power Pb, the half-cycle is judged to be in a short circuit state; when the number of jumps of the current signal derivative I' is greater than or equal to 1, the half-cycle is judged to be in a lintel blasting state.

[0053] It should be noted that the jump of the current signal derivative I' is caused by a sharp change in current. For example, the value of the 400th current signal derivative is 5, and the 401st current signal derivative begins to become 30, then it is determined that the current signal derivative has jumped. If the current signal derivative has been within the preset range [Ia', Ib'], it proves that the current change is small, and it is a short-circuit curve. Furthermore, the characteristic of the short circuit is that due to the mutual contact between the weldments and the extremely small change in welding resistance during the half-cycle, the change law of current with voltage shows the characteristics of a weak inductive loop, that is, the current phase lags slightly behind the voltage phase. The purpose of the short circuit is to quickly input heat.

[0054] The characteristic of the circuit breaker is that there is no contact between the weldments within a half cycle. At this time, the welding circuit is disconnected, but due to the existence of the primary circuit of the transformer, the change law of current with voltage shows a strong inductive circuit characteristic, that is, the current phase lags behind the voltage phase by about 90°. The purpose of the circuit breaker is to give a certain amount of time for the heat to diffuse evenly to prevent local overheating.

[0055] According to the no-load power of the transformer during welding, which fluctuates between 15 and 30 kW, the Pa value can be set at 30 to 40 kW. According to the short-circuit power of welding, which is between 100 and 250 kW, the Pb value can be set at 90 to 100 kW. a ',I b '] is to calculate the range based on the curve, such as Figure 3 and Figure 4 As shown, it can be set to [-10, 10], the range of Ia' can be selected from -20 to -5, and the range of Ib' can be selected from 5 to 20. It is assumed that there is no step phenomenon in the curve and the current continuity is very good. At the same time, the auxiliary judgment power P should be greater than the judgment basis Pb. By calculating and judging the power P and the current signal derivative I', the open circuit, short circuit and beam explosion status in the welding process can be accurately identified, thereby achieving precise control of the welding process, improving the stability and controllability of the welding process, and reducing the welding quality fluctuation caused by the current threshold setting deviation or experience dependence.

[0056] In an optional example of this embodiment, when the jump number of the current signal derivative I' is equal to 1, the half cycle is judged to be in a single-beam blasting state; when the jump number of the current signal derivative I' is greater than 1, the half cycle is judged to be in a multi-beam blasting state.

[0057] Specifically, Figure 5 and Figure 6As shown in the figure, the characteristic of beam explosion is that the contact resistance of the weldment changes sharply within a half cycle, which causes the welding current to increase with the increase of voltage at the beginning, and then the welding circuit is broken due to the beam explosion, and the current decreases sharply. According to the number of explosions within a half cycle, it can be further divided into single beam explosion and multiple beam explosion. The purpose of beam explosion is to achieve a rapid increase in the end surface temperature through rapid burning of the end surface. Multiple beam explosion is a more ideal explosion state, and a large single beam explosion during the advancement of the jaws is often a sign of a short circuit.

[0058] For single beam blasting, the jump number of the current signal derivative I' is 1, and the single beam blasting with larger power can be proposed based on the power P value. For a flash welding process, any stage is actually a combination of the above four states. By judging the jump number of the current signal derivative I', the single beam blasting and multi-beam blasting states in the welding process can be accurately identified, thereby achieving precise control of the welding process.

[0059] In an optional embodiment of the present invention, in the flash flat welding stage, the process parameters of the half cycle include the first welding voltage V1, the first jaw no-load speed v max1 , and the first target burning speed v t1 In the pulsation stage, the process parameters of the half cycle include the second welding voltage V2, the second jaw no-load speed v max2 , short-circuit static pressure F, total stage duration T and stage heating duty cycle D; in the continuous stage and acceleration stage, the process parameters of the half cycle include the third step voltage V3, the fourth step voltage V4, the second target burning speed v t2 and the third target burning speed v t3 .

[0060] like Figure 7 As shown, the pulsation stage is essentially a cyclic process of "breaking circuit-beam blasting-short circuit-beam blasting-breaking circuit", and the periodic short circuit preheating effect is achieved by adjusting the parameters. The rail flash welding control method and device proposed in the present invention can analyze the state of the rail welding end face in real time through the hardware loop and calculation method, and directly apply the analysis results to the control of the welding process.

[0061] Specific to each stage:

[0062] 1. Flashing stage: Traditionally, the flashing stage aims to preliminarily heat the rail end face and make it basically burn-flat. Necessary control parameters include welding voltage V1, first jaw no-load speed v max1 and target burning speed v t1 At the beginning of the phase, the first jaw moves at a higher speed v max1 When the first short circuit or beam explosion occurs, the jaw forward speed is switched to the set target burning speed vt1 Due to the different initial states of the end faces, if the jaw speed is constant at this time, a short circuit may occur. Therefore, in actual operation, the PID dynamic speed adjustment should be performed according to the end face state. When the burning speed of the rail stabilizes to the specified speed under the set conditions, it is considered that the temperature field of the end face tends to be stable and can enter the next stage.

[0063] 2. Pulsation stage: Necessary control parameters include welding voltage V2, second jaw no-load speed v max2 , static pressure F during short circuit, total duration T of the stage and heating duty cycle D of the stage. Heating duty cycle D is used to control the ratio of short circuit and open circuit state within 1 second. The welding voltage is set to a constant V2, and the second jaw moves forward at an idle speed v max2 , until a short circuit occurs between the end faces and the number of short circuit states reaches the set value of the duty cycle D. At this time, the jaws dynamically adjust the speed to keep the pressure value of the top forging cylinder at the static pressure F. Subsequently, the second jaw moves at an unloaded speed v max2 Move back until a circuit is broken, keep the jaws unchanged, and make the number of circuit breaking states reach the set value of the duty cycle D.

[0064] 3. Continuous stage and acceleration stage: Necessary control parameters include step voltages V3 and V4, target burning speed v t2 and v t3 During welding, the system will monitor the current end face status according to the set voltage value. In the initial stage, the burning speed should be lower than the target speed. When the end face stability field gradually stabilizes, the actual speed will be close to the target burning speed. When the speed reaches the target, the stage ends. In the stage adjustment, the dynamic PID adjusts the forward speed to ensure the actual burning speed.

[0065] 4. Upsetting stage: The parameter control in the upsetting stage is not significantly different from that in the ordinary process.

[0066] The rail flash welding control method proposed in the present invention realizes accurate control and optimization of the welding process. In different welding stages, by setting corresponding process parameters, not only the stability and controllability of the welding process are improved, but also the welding quality fluctuation caused by the current threshold setting deviation or experience dependence is reduced, the complexity of parameter setting is simplified, and the automatic dynamic adjustment of each process stage is realized, the uniformity of the quality of the welding joint and the precision of the heat input control are improved, and the adaptability to complex working conditions is enhanced.

[0067] In an optional example of this embodiment, during the flash flat welding stage, the actual burning speed of the rail within a preset time is measured, and when the actual burning speed reaches the first target burning speed v t1 Finally, the flash flat welding stage is ended;

[0068] In the continuous stage and the acceleration stage, the actual burning speed of the rail is measured within the preset time. When the actual burning speed reaches the second target burning speed v t2 , it is considered that the temperature field has reached the second target effect. When the actual burning rate reaches the third target burning rate v t3 , it is considered that the temperature field has achieved the third target effect.

[0069] Specifically, in the conventional welding process, the welding voltage V1 and the first jaw no-load speed v max1 These parameters are usually set based on the operator's experience or established process standards. In the flash flat stage, the traditional method usually determines when to end the stage based on the preset time or burn-off amount. However, the rail flash welding control method of the present invention introduces a new control logic, which measures the burn-off speed within a period of time (for example, within 1 second) and sets the burn-off speed to the target burn-off speed v when the burn-off speed reaches the target burn-off speed v. t1 (This speed can be set between 0.3-0.6mm / s based on experience, or adjusted according to specific process requirements), it is considered that the flash leveling stage can be ended.

[0070] Among these parameters, some are set directly and belong to open-loop control, while others are obtained through measurement. For example, the welding voltage V2 is set directly after the voltage is calibrated to the thyristor conduction angle; the second jaw no-load speed v max2 This is achieved by calibrating the forward speed of the cylinder without load, which is usually done through servo valve speed control. The total duration of the stage T is controlled by PLC timing. Once the preset time is reached, the stage ends.

[0071] On the other hand, the static pressure F during short circuit and the stage heating duty cycle D are obtained through measurement. The static pressure F is obtained by measuring the hydraulic pressure of the current welding in real time through a pressure sensor and converting it according to the area of ​​the cylinder. If the pressure is insufficient, the cylinder will move forward to increase the pressure; if the pressure is too high, the cylinder will retreat to reduce the pressure. The PID algorithm is usually used to achieve precise control of the F value. The heating duty cycle D is determined by calculating the current state of each half cycle. For example, in a 10-second pulsation process, if about 1,000 half cycles are measured, 500 of which are short circuits and 500 are the sum of lintel explosions and open circuits, then the D value is 50%. In implementation, it is possible to control the welding process parameters only by the stage heating duty cycle D, without the need to control it through the coordination of current and speed in the prior art.

[0072] The core of the rail flash welding control method proposed in the present invention is to achieve a basically constant heat input by fixing the short-circuit cycle. On this basis, the traditional time and burn-off amount control method is no longer used, but the actual burn-off speed control method is adopted. Under the same voltage setting conditions, once the target burn-off speed is reached, it is considered that the joint temperature field has reached the target effect, and the next stage of action is executed. Step voltages V3 and V4, target burn-off speed v t2 and v t3 These are all preset parameters, among which the voltage setting is the same as the traditional process parameters, usually in the range of 350-380V. t2 and v t3 It is determined by calculating the actual rail consumption rate within a period of time (for example, within 1 second).

[0073] In traditional processes, the movement of the jaws is usually performed forward or backward according to the current value. Most of these movements are preset constant values, or dynamic values ​​processed by PID. The end of the welding stage is usually controlled by time and displacement. However, this method has a difficulty when using the target burning speed: when the rail moves forward but does not actually burn (such as the circuit breaker state), the forward speed cannot accurately reflect the burning speed. The present invention can eliminate the movement of the circuit breaker stage through half-cycle judgment, take the actual start of burning as the calculation starting point, and then calculate the current real-time burning speed based on the rail consumption and the time elapsed.

[0074] Through closed-loop monitoring and feedback correction of the burning speed at each stage, accurate analysis of the thermal state of the end face and intelligent decision-making of process actions are achieved. In the flash leveling stage, the technical means of eliminating invalid mechanical strokes are used to ensure that the calculated burning speed value truly reflects the energy input efficiency of the end face, so that the uniformity of weld pretreatment and the removal effect of oxide film are significantly improved. In the continuous and accelerated stages, the setting of graded target burning speed converts the macroscopic physical characteristics of the weld temperature field into quantifiable and controllable process parameter control target values, effectively solving the time domain mismatch problem between heat input and mechanical action in traditional processes. Especially in the accelerated burning stage, the multi-level trigger mechanism based on the speed threshold makes the beam blasting frequency in the optimal process window, forming a stable and dense liquid metal migration mode, greatly reducing the risk of interface pores and unfused, and ultimately achieving high consistency control of rail consumption and predictability of mechanical properties of welded joints.

[0075] In the present invention, the flash flat welding stage, the pulsation stage, the continuous stage and the acceleration stage are four process stages of welding, which are four welding states with different characteristics obtained by setting different process parameters, and are mainly distinguished from the macro process curve. The open circuit state, the short circuit state and the lintel blasting state are based on the end face state of the rail to be welded, which is a more microscopic state. In theory, the end face state of the rail in the flash flat welding stage and the pulsation stage must be alternating between the open circuit state, the short circuit state and the lintel blasting state. The most ideal state in the continuous stage and the acceleration stage is that there is no open circuit state, the short circuit state and the lintel blasting state, but in actual production, they all exist, but the open circuit state and the short circuit state exist for a shorter time.

[0076] The detailed explanation of the above-mentioned embodiments is only intended to explain the present invention so as to facilitate a better understanding of the present invention. However, these descriptions cannot be interpreted as limitations on the present invention for any reason. In particular, the various features described in different embodiments may also be arbitrarily combined with each other to form other embodiments. Unless there is a clear description to the contrary, these features should be understood to be applicable to any embodiment and are not limited to the described embodiments.

Claims

1. A rail flash welding control method based on welding microstate discrimination, characterized in that: The rail flash welding control method comprises: During the flash welding process, the voltage and current of the welding primary circuit are sampled and sampling data is obtained, and the sampling data is truncated according to the half cycle of the alternating current; Calculating the current signal derivative and power in each half cycle based on the truncated sampling data; Determine the welding state of the corresponding half cycle according to the current signal derivative and the power; The welding process parameters of the rail flash welding are regulated according to the welding state.

2. The rail flash welding control method based on welding microstate identification according to claim 1, characterized in that: The set of sampling data of the truncated current is {…, (Ta, Ia), …, (Tb, Ib), …}, and the current signal derivative I' at the current moment is Ib-Ia) / (Tb-Ta); wherein T is the sampling moment, and I is the current at that moment.

3. The rail flash welding control method based on welding microstate identification according to claim 1, characterized in that: The power calculation formula is: Wherein, u(k) is the voltage sequence, and u(k)={U1,…Un}; i(k) is the current sequence, and i(k)={I1,…In}.

4. The rail flash welding control method based on welding microstate identification according to claim 1, characterized in that: When the power P is less than the first preset power P a , it is determined that the half cycle is in an open circuit state; When the current signal derivative I is within the preset range [I a ',I b '], and the power P is greater than the second preset power P b , it is determined that the half cycle is in a short-circuit state; When the jump times of the current signal derivative I' is greater than or equal to 1, it is determined that the half cycle is in a beam bursting state.

5. The rail flash welding control method based on welding microstate identification according to claim 4, characterized in that: When the jump number of the current signal derivative I' is equal to 1, it is judged that the half cycle is in a single beam blasting state; When the jump times of the current signal derivative I' is greater than 1, it is determined that the half cycle is in a multi-beam explosion state.

6. The rail flash welding control method based on welding microstate identification according to claim 1, characterized in that: In the flash flat stage, the process parameters of the half cycle include the first welding voltage V1, the first jaw no-load speed v max1 , and the first target burning speed v t1 ; In the pulsation stage, the process parameters of the half cycle include the second welding voltage V2, the second jaw no-load speed v max2 , static pressure F during short circuit, total duration T of the stage and duty cycle D of the stage heating; In the continuous stage and the acceleration stage, the process parameters of the half cycle include the third step voltage V3, the fourth step voltage V4, the second target burning speed v t2 and the third target burning speed v t3 .

7. The rail flash welding control method based on welding microstate identification according to claim 6, characterized in that: During the flash flat welding stage, the actual burning speed of the rail is measured within a preset time. When the actual burning speed reaches the first target burning speed v t1 Then the flash flat welding stage is ended; In the continuous stage and the acceleration stage, the actual burning speed of the rail within the preset time is measured. When the actual burning speed reaches the second target burning speed v t2 , it is considered that the temperature field has reached the second target effect, and when the actual burning rate reaches the third target burning rate v t3 , it is considered that the temperature field has achieved the third target effect.

8. A rail flash welding control device based on welding micro-state identification, characterized in that: The flash welding control device comprises: A voltage sensor is arranged on the welding primary circuit, and the voltage sensor samples the voltage of the welding primary circuit and obtains voltage sampling data; A current sensor is arranged on the primary welding circuit, and the current sensor performs current sampling on the primary welding circuit and obtains current sampling data; A programmable controller, which determines the state of the welding primary circuit according to the voltage sampling data and the current sampling data, and controls the welding process according to the state of the welding primary circuit in combination with set process parameters; The frame is used for clamping and centering the steel rails to be welded, and the movement of the frame is controlled by the process parameters.

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