A smoothing slope connection grinding method for low-profile defects of rail

Abstract

The present invention relates to a smooth slope connection grinding method for rail low-tread defects, belonging to the field of engineering technology, and includes: initialization; the laser array scanner of the grinding equipment scans the rail, analyzes the scanned data, and discovers the low-tread points of the rail; locates the low-tread points, and the grinding head of the grinding equipment grinds from the low-tread points to both sides until the low-tread points are ground and compliant; the grinding equipment moves to one side for grinding, and it is detected that the single-sided slope is completed; then it moves to the other side for grinding until the double-sided grinding slope is completed. By using this method, the problem of the smooth slope connection between the interface after grinding the rail low-tread defect and the original rail surface can be solved, and the problem of excessive abruptness at the connection between the grinding area and the original rail surface can be avoided.

Description

Technical Field

[0001] The present invention belongs to the field of engineering technology, and particularly relates to a smooth slope connection grinding method for low-profile defects of steel rails. Background Art

[0002] Most common damages to high-speed railway steel rails are mostly between 0.2 mm and 0.5 mm in depth. It is impossible to accurately complete the grinding of small defects using large grinding trains. The operation of small grinding vehicles mainly relies on manual labor, with low efficiency, inability to guarantee quality, and prone to over-grinding.

[0003] At present, there are mainly two categories of equipment for steel rail grinding. One is a large grinding vehicle, which mainly realizes the smooth slope transition between the ground surface and the unground surface of the steel rail through the combination of multiple grinding heads. Due to the high driving speed of the large grinding vehicle (12 - 18 km per hour) and limited adjustment accuracy of the grinding wheels, the smooth slope length of the steel rail grinding requires 150 m. This method is only suitable for the smooth slope of long-distance steel rail grinding and cannot complete the grinding of low-profile defects of steel rails less than 0.4 mm.

[0004] The other is a small manual grinding vehicle, which mainly completes the grinding of the steel rail by controlling the angle of the contact surface between the grinding wheel and the steel rail. Because there is no stable reference surface, the smooth slope operation of manual grinding mainly relies on the experience of the grinding operator. Near the interface connection position, passive grinding is adopted, that is, a certain pressure is given to the grinding wheel by relying on the gravity of the grinding vehicle, and the grinding is completed by dragging from the lowest point to the highest point. Such a method cannot guarantee the consistency of the smooth slope operation and the stability of the grinding quality. Over-grinding is prone to occur in actual operation, thus reducing the service life of the steel rail.

[0005] CN202410493237.1 A method for grinding the unevenness of the rail surface within 3 m of the welded joint of high-speed railway steel rails. This method for grinding the unevenness of the welded joint of the steel rail mainly solves the grinding of the convexity defect after the welding of the steel rail weld, and cannot solve the grinding problem of the steel rail depression.

[0006] CN202411334649.7 Precision grinding process method for large machines. The grinding of this large grinding vehicle is only suitable for solving the grinding of the straightness and profile of long-distance steel rails, and cannot solve the smooth slope problem of the grinding interface in local areas of steel rails, especially in short-distance (less than 4 m) local areas.

[0007] Under the current background of the rapid development of high-speed railways, the existing two categories of grinding equipment cannot meet the growing need for smooth slope connection of the interface after short-distance local grinding of steel rails. A method that can automatically complete the smooth slope connection between the ground surface and the unground surface is particularly important. Summary of the Invention

[0008] To solve the above technical problems, the present invention provides a smooth slope connection grinding method for low-profile defects of steel rails. The present invention aims to automatically complete the slope connection problem of the grinding surface of high-speed railway steel rails by precisely controlling the actions of the grinding equipment. According to the regulations, the slope rate in the vertical direction of the rail body flatness in the allowable deviation of rail flatness is less than or equal to 0.2 mm / m, that is, a slope rate of 0.2‰.

[0009] The specific technical solution is as follows: A smooth slope connection grinding method for low-profile defects of steel rails, including:

[0010] Initialization;

[0011] The laser array scanner of the grinding equipment scans the steel rail, analyzes the scanned data, and discovers the low-profile points of the steel rail;

[0012] Locate the low-profile points, and the grinding head of the grinding equipment grinds from the low-profile points to both sides until the grinding of the low-profile points meets the requirements;

[0013] The grinding equipment moves to one side for grinding and detects the completion of the single-side slope;

[0014] Move to the other side for grinding to complete the double-side grinding slope.

[0015] The present invention has the following beneficial effects:

[0016] Using this method, the slope connection problem between the interface after grinding the low-profile defects of the steel rail and the original rail surface can be solved, and the problem of excessive abruptness at the connection between the grinding area and the original rail surface can be avoided. The curve after grinding by this method has better connection smoothness, reduces the impact when the wheel passes, and improves the comfort of vehicle driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the grinding equipment of the present invention;

[0018] Figure 2 It is a flowchart of a smooth slope connection grinding method for low-profile defects of steel rails of the present invention;

[0019] Figure 3a It is a side view of the grinding surface after the first grinding;

[0020] Figure 3b It is a side view of the grinding surface after the second grinding;

[0021] Figure 3c It is a side view of the grinding surface after grinding is completed;

[0022] Figure 4 It is a comparison diagram of the grinding surface of the present invention and the grinding surface of the prior art.

[0023] The reference numerals in the figure are: running wheel 1, grinding wheel 2, grinding head 3, frame 4, guide rail 5, laser array scanner 6. Detailed implementation manners

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, the present invention adopts the following technical solutions.

[0025] The present invention relates to a method for smoothly slope-connected grinding of low-tread defects of steel rails. The low-tread defect refers to a depression of the steel rail, and the low-tread point refers to the area with the lowest position of the low-tread defect. As Figure 1 shown, the grinding device includes a running wheel 1, a grinding wheel 2, a grinding head 3, a frame 4, a guide rail 5, and a laser array scanner 6, which realizes functions of automatic grinding, automatic running, and automatic measurement. The grinding device scans the steel rail through the laser array scanner 6 to obtain the low-tread points; the grinding wheel 2 is controlled by a servo motor and a lead screw, and the grinding wheel 2 moves up and down along the guide rail 5. The grinding wheel 2 can move left and right and back and forth along the frame 4 through the grinding head 3. The control accuracy of the grinding wheel is 0.01 mm, and the grinding device can realize self-running by using a driving motor.

[0026] As Figure 2 shown, a flowchart of a method for smoothly slope-connected grinding of low-tread defects of steel rails according to the present invention specifically includes:

[0027] Initialization;

[0028] The laser array scanner 6 scans the steel rail, analyzes the scanned data, and discovers the low-tread points of the steel rail;

[0029] Locate the low-tread points, and the grinding head 3 grinds from the low-tread points to both sides until the low-tread points are ground to compliance;

[0030] The grinding device moves to one side for grinding, and detects that the single-side slope connection is completed;

[0031] Move to the other side for grinding, and complete the double-side grinding slope connection.

[0032] Among them, the initialization includes: placing the grinding device on the steel rail, and through adjustment, making the grinding plane of the grinding wheel of the grinding device parallel to the tangent plane of the rail surface of the steel rail.

[0033] Among them, the laser array scanner 6 scans the rail, analyzes the scanned data, and discovers the low-profile points of the rail; it includes: starting the grinding equipment, driving the belt through the servo motor to move the grinding equipment on the rail to be ground, the laser array scanner 6 on the grinding equipment scans the rail, collects the surface data of the rail, and through analysis, calculates the low-profile points of the rail to be ground.

[0034] Among them, locate the low-profile points, and the grinding head 3 grinds from the low-profile points to both sides, and the low-profile points are ground to compliance; it includes:

[0035] Control the grinding wheel 2 on the grinding head 3 to move to the center of the low-profile point, and control the grinding wheel 2 to grind from the middle to both sides at a slope of 0.2 per thousand; repeat multiple times until the low-profile points are ground to compliance; that is, the vertical deviation of the rail straightness in the allowable deviation of the rail straightness is less than or equal to 0.2 mm / 1 m.

[0036] The grinding equipment moves to one side for grinding, and the detection of the single-sided slope is completed; it includes:

[0037] Step 1) Drive the left traveling wheel of the grinding equipment to the lowest point of the low-profile point through the motor. At this time, the right traveling wheel of the grinding equipment will be on the original rail surface; as Figure 3a shown.

[0038] Step 2) Start the grinding head to move back and forth on the grinding equipment for grinding until Figure 3c the area above the red line A1B1 in is ground, and the first grinding is completed;

[0039] Step 3) After the first grinding is completed through laser scanning detection, the grinding equipment starts to move to the right. Calculated by the moving distance of the right traveling wheel rail surface, it moves 1 cm each time, and repeat the action of Step 2 until the left traveling wheel moves to the height of the original rail surface; as Figure 3b shown.

[0040] Move to the other side for grinding, and the bilateral grinding slope is completed; it includes:

[0041] Step 1) The grinding equipment moves to the left until the right traveling wheel reaches the lowest point of the low-profile point, and the left traveling wheel will be on the original un-repaired rail surface at this time;

[0042] Step 2) Start the grinding equipment, and the grinding head grinds from the low point to the high point until the grinding is completed;

[0043] Step 3) After the first grinding is completed through laser scanning detection, the grinding equipment starts to move to the left. Calculated by the moving distance of the left traveling wheel rail surface, it moves 1 cm each time, and repeat the action of Step 2 until the right traveling wheel moves to the height of the original rail surface.

[0044] After the bilateral grinding is completed, the straightness curve of the rail will be presented as Figure 4The curves shown: As can be seen from the figure, the curve 2 ground by the grinding equipment of the present invention has better smoothness characteristics than the curve 1 ground by the prior art.

[0045] To ensure the smooth connection between the ground surface and the unground surface of the rail, a passive grinding method is adopted, that is, the grinding wheel is pressed on the rail only by its own weight, and the control part does not apply pressure to the grinding wheel. The slope connection is completed by first moving the grinding equipment and then moving the grinding wheel.

[0046] The present invention automatically completes the positioning of the cutter head's cutting position through laser scan data analysis; automatically grinds the low-tread points through program control; completes the slope connection between interfaces by the passive grinding method where the grinding head is pressed on the rail by its own weight; and completes the grinding of the slope curve by moving the whole equipment.

[0047] By moving the grinding equipment to one side, such as Figure 3c shown as moving to the right, the side view of the ground surface is as Figure 3c shown. The first side view line during grinding is A1B1; the second side view line after moving and grinding is A2B2; the third is A3B3; the fourth is A4B4, and so on, until An reaches the rail plane. At this time, the curve formed by A1A2A3A4…An is the smooth slope curve between the ground surface and the unground surface of the rail low-tread defect.

[0048] During the grinding process, an adaptive control model based on machine learning is introduced. Through machine learning algorithms, an adaptive control model is established to dynamically adjust the movement trajectory of the grinding head according to the real-time scan data of the rail surface grinding. The grinding method using the adaptive control model includes:

[0049] Data acquisition: During the grinding process, the laser array scanner continuously acquires data on the rail surface, including the depth, length at the rail low-tread points, and the actual amount completed for each grinding.

[0050] Model training: Use historical grinding data to train the machine learning model so that it can automatically generate the optimal grinding path and force according to different rail surface characteristics.

[0051] Real-time adjustment: During the grinding process, the model dynamically adjusts the movement trajectory of the grinding head according to the real-time acquired data to ensure the optimization of the grinding effect.

[0052] The grinding algorithm of the adaptive control model includes:

[0053] Select the reinforcement learning model Q-learning. In each control cycle, select the optimal action according to the current state to generate the movement trajectory of the grinding head. After executing the action, observe the next state and reward, and update the model. Through continuous learning and optimization, generate the optimal grinding path.

[0054] Q-learning is a reinforcement learning algorithm based on the Q-value function, which evaluates the long-term reward of taking a certain action in a certain state. The update formula of the Q-value function is as follows:

[0055] (1)

[0056] where: s: the current state; : the current action; : the next state; : the next action; R: the immediate reward; : the learning rate, used to control the weight of new information, with the initial value set to 0.1; : the discount factor, controlling the importance of future rewards, with the initial value set to 0.95.

[0057] In each control cycle, the process of selecting the optimal action according to the current state s is as follows:

[0058] The first step, Q-value query: Query the Q-values of all possible actions in the current state s ;

[0059] The second step, action selection: Select the current action that maximizes the Q-value in the current state s:

[0060] ;

[0061] The third step, execute the action: Execute the selected current action , and observe the next state s′ and the immediate reward R.

[0062] The current state s contains all the information related to the grinding operation, used to describe the current environment and the state of the grinding head. The state is defined as:

[0063] ;

[0064] where:

[0065] D: the depth of the low step point (unit: mm).

[0066] W: the width of the low step point (unit: mm).

[0067] x: the lateral position of the grinding head on the rail surface (unit: mm).

[0068] y: the longitudinal position of the grinding head on the rail surface (unit: mm).

[0069] V: the current moving speed of the grinding head (unit: mm / s).

[0070] R is the immediate feedback obtained after performing an action, used to evaluate the quality of the action. During the rail grinding process, the design of the reward function encourages the grinding head to complete the grinding task efficiently and precisely. The reward function is defined as:

[0071] (2)

[0072] Where: : The surface irregularity of the rail after grinding (unit: mm).

[0073] E: The grinding efficiency (the length ground per unit time, unit: mm² / s).

[0074] F: The grinding force of the grinding head (unit: N).

[0075] is the surface irregularity of the rail after grinding 's weight coefficient, β is the weight coefficient of the grinding efficiency 's weight coefficient, γ is the weight coefficient of the grinding force of the grinding head 's weight coefficient. (The initial values are set to: 0.4, 0.3, 0.3).

[0076] After performing an action, observe the next state s′ and the immediate reward R, and update the Q-value function. Through Q-learning, by defining the state, calculating the reward, and updating the model, continuously learn and optimize to generate the optimal grinding path. This method can significantly improve the accuracy and efficiency of rail grinding, reduce manual intervention, and achieve an intelligent and automated grinding process.

[0077] Model training includes:

[0078] Divide the data into a training set and a test set; use the training set to train the machine learning model; use the test set to evaluate the performance of the model.

[0079] This method uses grid search. Through grid search, traverse all combinations, train and evaluate the model for each hyperparameter combination, and finally select the hyperparameter combination with the best performance on the validation set through experimental verification. For example, according to a certain grinding equipment for testing, the specific results are as follows:

[0080] In formula (1), : The learning rate is adjusted to 0.05; : The discount factor is adjusted to 0.95, and the weight α of the irregularity in formula (2) is adjusted to: 0.5; the weight β of the grinding efficiency is adjusted to 0.3; the weight γ of the grinding force is adjusted to 0.2.

Claims

1. A method for smoothly grinding rail low-stepping defects along the slope, characterized in that: The following steps are involved: initialization; The laser array scanner of the grinding equipment scans the rails, and the scan data is analyzed to find the low stepping point of the rails; Locate the low stepping point, and the grinding head of the grinding equipment grinds from the low stepping point to both sides, and the low stepping point grinding complies with the regulations; The grinding equipment moves to one side to grind, and the inspection is completed on one side along the slope; Move to the other side and grind, and complete the double-sided grinding along the slope; The grinding equipment moves to one side to grind and detect that the single side is completed along the slope; including: Step 1) The left end running wheel of the grinding equipment is moved to the lowest point of the low stepping point, at which time the right end running wheel of the grinding equipment will be on the original rail surface; Step 2) Start the grinding wheel and move it back and forth on the grinding device to grind until the area is polished, completing the first grinding; Step 3) After the first grinding is completed through laser scanning detection, the grinding equipment starts to move to the right, and the distance of the rail surface movement of the right running wheel is calculated. Each time it moves a fixed distance, the step 2) is repeated until the left running wheel moves to the original rail surface height; Move to the other side and grind, double-sided grinding is completed along the slope; including: Step 1) The grinding equipment moves to the left until the right running wheel reaches the lowest point of the low step point, and the left running wheel will now be on the original unrepaired rail surface; Step 2) Start the grinding equipment, and grind the grinding wheel from the low point to the high point until the grinding is completed; Step 3) After the first grinding is completed through laser scanning detection, the grinding equipment starts to move to the left, and the distance moved by the left running wheel is calculated. Each time it moves a fixed distance, step 2) is repeated until the right running wheel moves to the original rail surface height.

2. A method for smoothly grinding rail low-stepping defects according to claim 1, characterized in that: Initialization includes: Place the grinding device on the rail so that the grinding plane of the grinding wheel on the grinding head is parallel to the rail surface tangent plane of the rail.

3. A method for smoothly grinding rail low-stepping defects according to claim 2, characterized in that: in, The laser array scanner of the grinding equipment scans the rails, and the scanning data is analyzed to find the low stepping point of the rails; including: starting the grinding equipment to move the grinding equipment on the rails to be ground, the laser array scanner on the grinding equipment scans the rails, collects the surface data of the rails, and finds the low stepping point of the rails to be ground after analysis.

4. A method for smoothly grinding rail low-stepping defects according to claim 3, characterized in that: in, Locate the low stepping point, and use the grinding head of the grinding equipment to grind from the low stepping point to both sides to make the low stepping point grinding comply with the regulations; including: Control the grinding wheel on the grinding head to move to the center of the low stepping point, and control the grinding wheel to grind from the middle to both sides at a slope of 0.2 thousandths; repeat several times until the low stepping point is ground to compliance.

5. A method for smoothly grinding rail low-stepping defects along the slope according to claim 4, characterized in that: Grinding compliance specifically means: the vertical deviation of the rail body straightness of the allowable deviation of rail straightness is less than or equal to 0.2mm / 1m.

6. A method for smoothly grinding rail low-stepping defects along the slope according to claim 2, characterized in that: Passive grinding is adopted, that is, the grinding wheel presses on the rail only by its own weight.

7. A method for smoothly grinding rail low-stepping defects along the slope according to claim 2, characterized in that: The down-slope connection is accomplished by moving the grinding equipment first and then the grinding wheel.

8. The method for smoothly grinding the low-stepping defect of a rail according to claim 1, characterized in that: The fixed distance is 1cm.

9. A method for smoothly grinding rail low-stepping defects along the slope according to claim 1, characterized in that: During the grinding process, an adaptive control model based on machine learning is introduced to dynamically adjust the motion trajectory of the grinding head according to the real-time scanning data of the rail surface grinding. The grinding methods using the adaptive control model include: Data collection: During the grinding process, the laser array scanner collects data on the rail surface in real time, including the depth and length of the rail's low step point and the actual amount of grinding completed each time; Model training: Use historical grinding data to train the machine learning model so that it can automatically generate the optimal grinding path and force based on different rail surface characteristics; Real-time adjustment: During the grinding process, the model dynamically adjusts the motion trajectory of the grinding head based on the real-time collected data to ensure the optimal grinding effect.

10. A method for smoothly grinding rail low-stepping defects according to claim 9, characterized in that: The polishing algorithm of the adaptive control model includes: The Q-learning reinforcement learning algorithm is used to evaluate the long-term benefits of taking a certain action in a certain state through the Q-value function. The update formula of the Q-value function is: （1） Among them: s is the current state; For the current action; For the next state; is the next action; R is the immediate reward; is the learning rate, is the discount factor; In each control cycle, the optimal action is selected according to the current state s The process is as follows: The first step is Q value query: query the Q value of all possible actions under the current state s ; Step 2: Action selection: Select the current action that maximizes the Q value in the current state. : ； Step 3: Execute the action: Execute the current action selected , and observe the next state s′ and immediate reward R; The current state s contains all the information related to the grinding operation, which is used to describe the current environment and the state of the grinding head. The state is defined as: ； in: D: Depth of low stepping point; W: width of low step point; x: lateral position of the grinding head on the rail surface; y: longitudinal position of the grinding head on the rail surface; V: current moving speed of the grinding head; R is the immediate feedback obtained after executing the action, which is used to evaluate the quality of the action. In the process of rail grinding, the design of the reward function encourages the grinding head to complete the grinding task efficiently and accurately. The reward function is defined as: （2） in: : Roughness of the rail surface after grinding; E: grinding efficiency; F: grinding force of the grinding head; The roughness of the rail surface The weight coefficient, β is the grinding efficiency The weight coefficient, γ is the grinding intensity The weight coefficient of After executing the action, the next state is observed And the immediate reward R, and update the Q-value function, through Q-learning, by defining the state, calculating the reward, updating the model, continuous learning and optimization, to generate the optimal polishing path.

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