A stress field prediction method for a winding type permanent magnet outer rotor elevator drum

Abstract

The present application relates to the technical field of stress field of drum, in particular to a kind of winding type permanent-magnet outer rotor hoist drum stress field prediction method.The present application is to solve the problem that the stress field of permanent-magnet outer rotor hoist drum cannot be predicted in prior art, therefore a new winding type permanent-magnet outer rotor hoist drum stress field prediction method is provided, comprising the following steps: one, establishing the three-dimensional geometric model of drum;Two, import three-dimensional geometric model into finite element analysis software;Three, obtain the simulation stress field of drum;Four, obtain the modal base function and modal coefficient capable of representing the simulation stress field of drum;Five, establish nonlinear relationship regression model and approximate reconstruction stress field;Six, predict the running position and steel wire rope tension at future time;Seven, the running position and steel wire rope tension at future time predicted are introduced into step five, so as to realize the prediction of stress field.The present application realizes the prediction of drum stress field.

Description

Technical Field

[0001] This invention relates to the field of drum stress field technology, specifically a method for predicting the stress field of a wound permanent magnet external rotor hoist drum. Background Technology

[0002] The hoist drum must withstand multiple forces, including the weight of the wire rope, the load of the hoisting container, and tension fluctuations during operation, resulting in a complex stress and strain distribution on the surface and inside of the drum.

[0003] The wound permanent magnet external rotor hoist is a type of hoist that connects the stator core to the main shaft via a flange, with the drum serving as the external rotor of the motor. Through the coupling of electromagnetic and permanent magnetic fields, the external rotor of the drum directly drives the wire rope to traction the load. This equipment is widely used in coal mines, metal mines, non-metal mines, and for personnel hoisting. As a highly efficient piece of equipment integrating drive and transmission functions, the wound permanent magnet external rotor hoist boasts advantages such as compact structure, small size, fast response, and high transmission efficiency. Compared to conventional hoists that use an indirect drive method involving an independent motor-reducer-drum, its integrated design of the motor rotor and drum eliminates the intermediate mechanical transmission link, reducing energy loss and equipment size while significantly improving transmission stiffness and dynamic response performance.

[0004] However, this integrated motor and drum design means that during hoist operation, the drum not only bears the weight of the wire rope itself, the hoisting load, and fluctuations in wire rope tension, but is also affected by the electromagnetic force generated by the motor. These effects cause a complex stress-strain distribution in the drum. Due to the special nature of the external rotor structure, the drum's strain not only affects its mechanical properties and fatigue life, but is also related to the electromagnetic characteristics of the motor. Changes in stress directly affect the uneven distribution of the motor's air gap, leading to electromagnetic force fluctuations and torque pulsations, reducing the system's control accuracy, and adversely affecting the hoist's operational stability and safety. Therefore, research on stress field prediction for permanent magnet external rotor hoist drums is of significant engineering importance for ensuring the safe and efficient mining of deep resources.

[0005] Currently, stress field monitoring of permanent magnet external rotor hoist drums mainly relies on strain gauges, fiber optic grating sensors, or accelerometers. While these methods can reflect the local stress conditions of the drum to some extent, they have the following shortcomings: ① The number of sensor placement points is limited, making it impossible to fully cover the entire drum surface and obtain a complete stress field distribution; ② Long-term operation of sensors is susceptible to wear, temperature drift, or electromagnetic interference, leading to decreased data accuracy and increased maintenance costs.

[0006] To overcome the problems of limited measurement points and high maintenance costs, the finite element method is also used in existing technologies to detect the stress field of the permanent magnet external rotor hoist drum. However, although the finite element analysis method can relatively comprehensively and accurately depict the stress characteristics under complex working conditions, the method has a large amount of calculation and is time-consuming. It is usually used for offline analysis in the design stage or after operation, which is difficult to meet the needs of real-time monitoring and prediction during operation and cannot provide effective early warning before failure occurs.

[0007] In the actual operation of a permanent magnet external rotor hoist, if there is a lack of means to predict the stress field of the drum, it is difficult to capture the potential dangerous state of the drum structure in time, and it is also impossible to effectively detect the abnormal air gap of the motor caused by drum deformation. Summary of the Invention

[0008] In order to solve the problem that the existing technology cannot predict the stress field of the permanent magnet external rotor hoist drum, the present invention provides a new method for predicting the stress field of the wound permanent magnet external rotor hoist drum.

[0009] This invention is achieved using the following technical solution:

[0010] A method for predicting the stress field of a wound permanent magnet external rotor hoist drum includes the following steps:

[0011] I. Establish a three-dimensional geometric model of the drum of the wound permanent magnet external rotor hoist with a rope groove structure;

[0012] 2. Import the three-dimensional geometric model established in step one into the finite element analysis software (ANSYS), and divide the application areas of different loads according to the contact position between the wire rope and the drum, including the full loop wire rope winding area, the non-full loop wire rope winding area, and the contact area with deflection angle.

[0013] 3. Calculate the loads corresponding to the full loop wire rope winding area, the non-full loop wire rope winding area, and the contact area with deflection angle, respectively, so as to obtain the load of the entire winding area of ​​the drum. Then, use the load as the load input to the three-dimensional geometric model in the finite element analysis software to obtain the simulated stress field of the drum.

[0014] Fourth, based on the simulated stress field of the drum obtained in step three, the modal basis functions and modal coefficients that can characterize the approximate stress field under any discrete operating state of the drum are obtained by using intrinsic mode decomposition.

[0015] 5. Establish a nonlinear regression model between the operating position, wire rope tension, and modal coefficients of the wound permanent magnet external rotor hoist, and use the modal basis functions and modal coefficients to approximately reconstruct the stress field;

[0016] VI. A gated recurrent unit neural network (GRU) is introduced to construct an operation status prediction model. This model is trained based on the temporal characteristics of historical operation data and can predict the future operating position and wire rope tension of the wound permanent magnet external rotor hoist.

[0017] 7. The future operating position and wire rope tension of the wound permanent magnet external rotor hoist predicted in step 6 are introduced into the nonlinear regression model established in step 5 to obtain the corresponding modal coefficients. Finally, the stress field is reconstructed based on the modal coefficients to achieve the prediction of the stress field.

[0018] Furthermore, the specific steps of step three include:

[0019] 3-1. For the area where the entire wire rope is wrapped:

[0020] 3-1.1 Calculate the tension attenuation coefficient for each complete loop of wire rope. :

[0021] ①

[0022] in, , These are the elastic moduli of the wire rope and the drum, respectively. This refers to the cross-sectional area of ​​a single wire rope. For the thickness of the drum wall, Where is the radius of the roller. Indicates the first Circle and the first The distance of the circle, For the current cycle to be calculated, For the first Circle Any circle between circles, For the current winding loop, Let be the deflection response function. for The decay rate parameter, Poisson's ratio for the wire rope;

[0023] 3-1.2 Calculate the average radial load generated by each full turn of wire rope wound around the drum surface. :

[0024] ②

[0025] in, For the first Wire rope tension For the overall tension of the wire rope, The contact width between the wire rope and the rope groove;

[0026] 3-2. For areas where the wire rope is not wrapped in a full loop:

[0027] Calculate the average radial load generated by a non-full loop of wire rope wound on the drum surface. for: ③

[0028] in, The angle between the tension direction of the non-full loop wire rope and the normal direction of the drum. For non-full loop steel wire rope winding angle;

[0029] 3-3. For contact areas with deflection angles:

[0030] When there is an angular deviation at the wire rope entry point, the average radial load on the drum. for:

[0031] ④

[0032] in, The angle at which the wire rope enters the rope. This refers to the winding angle of the wire rope within the area affected by the deflection angle. Let be the normal component of the wire rope tension and ;

[0033] When there is an angle at the wire rope inlet and outlet positions, the average axial load on the drum. for:

[0034] ⑤

[0035] 3-4. The loads calculated using formulas ②, ③, ④, and ⑤ are used as load inputs for the three-dimensional geometric model in the finite element analysis software to obtain the simulated stress field of the roller.

[0036] Furthermore, the specific steps of step four include:

[0037] 4-1. Divide a complete operation process (lifting, hovering, and lowering) of a wound permanent magnet external rotor hoist into three parts. For each discrete operating state, the simulated stress field of the roller under each discrete operating state is obtained using step three. Simulated stress field of the roller under discrete operating conditions , Given the number of spatial nodes for each discrete operating state, the stress fields of the m discrete operating states are finally constructed into a nodal stress field matrix. ,Right now

[0038] ⑥

[0039] 4-2. Use intrinsic mode decomposition to obtain the modal basis functions and modal coefficients that can characterize the simulated stress field under arbitrary discrete operating conditions of the drum;

[0040] Intrinsic mode decomposition formula middle, Let be a left singular vector matrix, whose column vectors are modal basis functions. It is a diagonal singular value matrix, and the magnitude of the singular values ​​reflects the energy contribution of each mode; Let be the right singular vector matrix, representing the direction of the corresponding mode coefficients. Select the first... After each mode, the mode coefficient matrix The stress field is approximated by combining the intrinsic mode decomposition formula:

[0041] ⑦

[0042] in, For the previous truncation The mode matrix of the first-order modal basis functions.

[0043] Furthermore, the specific steps of step five include:

[0044] 5-1. Using the collected data on the operating position and wire rope tension of the wound permanent magnet external rotor hoist, and combining the modal coefficients obtained by the intrinsic mode decomposition in step four at the corresponding operating position, construct a dataset corresponding to the operating position, wire rope tension, and modal coefficients.

[0045] 5-2. Using the dataset constructed in step 5-1 as training samples for the deep operator network, the network parameters of Branch Net and Trunk Net in the deep operator network are continuously optimized through iterative optimization to form a network that can represent the running position. The overall tension of the wire rope A nonlinear regression model relating the modal coefficients;

[0046] 5-3. Using the nonlinear regression model formed in step 5-2, combine the outputs of Branch Net and Trunk Net through inner product operation to obtain the... Modal coefficients :

[0047] ⑧

[0048] in, For hidden feature dimensions, For running location The overall tension of the wire rope Features For the corresponding modal features;

[0049] 5-4. In the offline simulation stage of the stress field, the stress field is approximately reconstructed using modal basis functions and modal coefficients. :

[0050] 9

[0051] in, For the first One modal basis function.

[0052] The beneficial effects of this invention are as follows:

[0053] 1) The stress field prediction method proposed in this invention, compared with the existing method that mainly relies on offline finite element calculation, can realize real-time prediction of stress field during operation based on wire rope tension and hoist operating position. At the same time, the method considers the wire rope deflection angle and tension attenuation effect in the calculation, which significantly improves the accuracy of stress field prediction.

[0054] 2) The stress field prediction method described in this invention considers both full-turn winding and non-full-turn winding states, thereby achieving refined calculation of the stress field during dynamic winding.

[0055] 3) The stress field prediction method described in this invention introduces the intrinsic mode decomposition method to characterize the stress field under each operating state as a combination of several modes and modal coefficients. By establishing a nonlinear mapping relationship between the operating position, wire rope tension and modal coefficients, and establishing a prediction model for the operating position and wire rope tension, it is possible to quickly predict the future operating state. Combined with the modal coefficient mapping relationship, it can predict the stress field at future moments, providing a reliable data basis for the structural safety assessment of the hoist and the air gap analysis of the motor. Attached Figure Description

[0056] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0057] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a flowchart of the prediction method described in this invention;

[0059] Figure 2 This is a schematic diagram comparing the predicted stress data obtained using the prediction method described in this invention with the measured stress data. Detailed Implementation

[0060] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0061] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0062] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0063] like Figure 1 As shown, a method for predicting the stress field of a wound permanent magnet external rotor hoist drum includes the following steps:

[0064] I. Establish a three-dimensional geometric model of the drum of the wound permanent magnet external rotor hoist with a rope groove structure;

[0065] 2. Import the three-dimensional geometric model established in step one into the finite element analysis software (ANSYS), and divide the application areas of different loads according to the contact position between the wire rope and the drum, including the full loop wire rope winding area, the non-full loop wire rope winding area, and the contact area with deflection angle.

[0066] 3. Calculate the loads corresponding to the full loop wire rope winding area, the non-full loop wire rope winding area, and the contact area with deflection angle, respectively, so as to obtain the load of the entire winding area of ​​the drum. Then, use the load as the load input to the three-dimensional geometric model in the finite element analysis software to obtain the simulated stress field of the drum.

[0067] The specific steps include:

[0068] 3-1. For the area where the entire wire rope is wrapped:

[0069] 3-1.1 Calculate the tension attenuation coefficient for each complete loop of wire rope. :

[0070] ①

[0071] in, , These are the elastic moduli of the wire rope and the drum, respectively. This refers to the cross-sectional area of ​​a single wire rope. For the thickness of the drum wall, Where is the radius of the roller. Indicates the first Circle and the first The distance of the circle, For the current cycle to be calculated, For the first Circle Any circle between circles, For the current winding loop, Let be the deflection response function. for The decay rate parameter, Poisson's ratio for the wire rope;

[0072] 3-1.2 Calculate the average radial load generated by each full turn of wire rope wound around the drum surface. :

[0073] ②

[0074] in, For the first Wire rope tension For the overall tension of the wire rope, The contact width between the wire rope and the rope groove;

[0075] 3-2. For areas where the wire rope is not wrapped in a full loop:

[0076] Calculate the average radial load generated by a non-full loop of wire rope wound on the drum surface. for: ③

[0077] in, The angle between the tension direction of the non-full loop wire rope and the normal direction of the drum. For non-full loop steel wire rope winding angle;

[0078] 3-3. For contact areas with deflection angles:

[0079] When there is an angular deviation at the wire rope entry point, the average radial load on the drum. for:

[0080] ④

[0081] in, The angle at which the wire rope enters the rope. This refers to the winding angle of the wire rope within the area affected by the deflection angle. Let be the normal component of the wire rope tension and ;

[0082] When there is an angle at the wire rope inlet and outlet positions, the average axial load on the drum. for:

[0083] ⑤

[0084] 3-4. The loads calculated using formulas ②, ③, ④, and ⑤ are used as load inputs for the three-dimensional geometric model in the finite element analysis software to obtain the simulated stress field of the roller.

[0085] Fourth, based on the simulated stress field of the drum obtained in step three, the modal basis functions and modal coefficients that can characterize the approximate stress field under any discrete operating state of the drum are obtained by using intrinsic mode decomposition.

[0086] The specific steps include:

[0087] 4-1. Divide a complete operation process (lifting, hovering, and lowering) of a wound permanent magnet external rotor hoist into three parts. For each discrete operating state, the simulated stress field of the roller under each discrete operating state is obtained using step three. Simulated stress field of the roller under discrete operating conditions , Given the number of spatial nodes for each discrete operating state, the stress fields of the m discrete operating states are finally constructed into a nodal stress field matrix. ,Right now

[0088] ⑥

[0089] 4-2. Use intrinsic mode decomposition to obtain the modal basis functions and modal coefficients that can characterize the simulated stress field under arbitrary discrete operating conditions of the drum;

[0090] Intrinsic mode decomposition formula middle, Represents transpose. Let be a left singular vector matrix, whose column vectors are modal basis functions. It is a diagonal singular value matrix, and the magnitude of the singular values ​​reflects the energy contribution of each mode; Let be the right singular vector matrix, representing the direction of the corresponding mode coefficients. Select the first... After each mode, the mode coefficient matrix The stress field is approximated by combining the intrinsic mode decomposition formula:

[0091] ⑦

[0092] in, For the previous truncation The mode matrix of the first-order modal basis functions;

[0093] 5. Establish a nonlinear regression model between the operating position, wire rope tension, and modal coefficients of the wound permanent magnet external rotor hoist, and use the modal basis functions and modal coefficients to approximately reconstruct the stress field;

[0094] The specific steps include:

[0095] 5-1. Using the collected data on the operating position and wire rope tension of the wound permanent magnet external rotor hoist, and combining the modal coefficients obtained by the intrinsic mode decomposition in step four at the corresponding operating position, construct a dataset corresponding to the operating position, wire rope tension, and modal coefficients.

[0096] 5-2. Using the dataset constructed in step 5-1 as training samples for the deep operator network, the network parameters of Branch Net and Trunk Net in the deep operator network are continuously optimized through iterative optimization to form a network that can represent the running position. The overall tension of the wire rope A nonlinear regression model relating the modal coefficients;

[0097] 5-3. Using the nonlinear regression model formed in step 5-2, combine the outputs of Branch Net and Trunk Net through inner product operation to obtain the... Modal coefficients :

[0098] ⑧

[0099] in, For hidden feature dimensions, For running location The overall tension of the wire rope Features For the corresponding modal features;

[0100] 5-4. In the offline simulation stage of the stress field, the stress field is approximately reconstructed using modal basis functions and modal coefficients. :

[0101] 9

[0102] in, For the first One modal basis function.

[0103] VI. A gated recurrent unit neural network (GRU) is introduced to construct an operational status prediction model. This model is trained based on the temporal characteristics of historical operational data and can predict the future operating position and wire rope tension of the wound permanent magnet external rotor hoist.

[0104] 7. Substitute the future operating position and wire rope tension of the wound permanent magnet external rotor hoist predicted in step 6 into formula 8 to derive and calculate the corresponding modal coefficients. Finally, based on the calculated modal coefficients, reconstruct the stress field using formula 9 to obtain the stress field at that moment, thereby completing the prediction of the stress field.

[0105] The prediction method described in this invention was integrated into a local server and combined with the Unity visualization platform and PLC data acquisition system to construct a deployable real-time monitoring and prediction platform. Validation was performed in a real-world operating environment, and the results showed that... Figure 2 As shown, the absolute error between the predicted stress data obtained by the prediction method described in this invention and the measured stress data is within 10%, demonstrating good engineering applicability and promotion potential.

[0106] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.

Claims

1. A method for predicting the stress field of a wound permanent magnet external rotor hoist drum, characterized in that, Includes the following steps: I. Establish a three-dimensional geometric model of the drum of the wound permanent magnet external rotor hoist with a rope groove structure; 2. Import the three-dimensional geometric model established in step one into the finite element analysis software, and divide the application areas of different loads according to the contact position between the wire rope and the drum, including the whole loop wire rope winding area, the non-whole loop wire rope winding area, and the contact area with deflection angle.

3. Calculate the loads corresponding to the full loop wire rope winding area, the non-full loop wire rope winding area, and the contact area with deflection angle, respectively, so as to obtain the load of the entire winding area of ​​the drum. Then, use the load as the load input to the three-dimensional geometric model in the finite element analysis software to obtain the simulated stress field of the drum. Fourth, based on the simulated stress field of the drum obtained in step three, the modal basis functions and modal coefficients that can characterize the approximate stress field under any discrete operating state of the drum are obtained by using intrinsic mode decomposition. V. Establish a nonlinear regression model between the operating position, wire rope tension, and modal coefficients of the wound permanent magnet external rotor hoist, and use modal basis functions and modal coefficients to approximately reconstruct the stress field. Specific steps include: 5-1. Using the collected data on the operating position and wire rope tension of the wound permanent magnet external rotor hoist, and combining the modal coefficients obtained through intrinsic mode decomposition in step four at the corresponding operating position, construct a dataset corresponding to the operating position, wire rope tension, and modal coefficients. 5-2. Using the dataset constructed in step 5-1 as training samples for the deep operator network, the network parameters of Branch Net and Trunk Net in the deep operator network are continuously optimized through iterative optimization to form a network that can represent the running position. The overall tension of the wire rope A nonlinear regression model relating the modal coefficients; 5-3. Using the nonlinear regression model formed in step 5-2, combine the outputs of Branch Net and Trunk Net through inner product operation to obtain the... Modal coefficients : ⑧ in, For hidden feature dimensions, For running location The overall tension of the wire rope Features For the corresponding modal features; 5-4. In the offline simulation stage of the stress field, the stress field is approximately reconstructed using modal basis functions and modal coefficients. : ⑨ in, For the first One modal basis function; VI. A gated recurrent unit neural network is introduced to construct an operation status prediction model. This model is trained based on the temporal characteristics of historical operation data and can predict the future operating position and wire rope tension of the wound permanent magnet external rotor hoist.

7. The future operating position and wire rope tension of the wound permanent magnet external rotor hoist predicted in step 6 are introduced into the nonlinear regression model established in step 5 to obtain the corresponding modal coefficients. Finally, the stress field is reconstructed based on the modal coefficients to achieve the prediction of the stress field.

2. The method for predicting the stress field of a wound permanent magnet external rotor hoist drum according to claim 1, characterized in that, Step three includes the following specific steps: 3-1. For the area where the entire wire rope is wrapped: 3-1.1 Calculate the tension attenuation coefficient for each complete loop of wire rope. : ① in, , These are the elastic moduli of the wire rope and the drum, respectively. This refers to the cross-sectional area of ​​a single wire rope. For the thickness of the drum wall, Where is the radius of the roller. Indicates the first Circle and the first The distance of the circle, For the current cycle to be calculated, For the first Circle Any circle between circles, For the current winding loop, Let be the deflection response function. for The decay rate parameter, Poisson's ratio for the wire rope; 3-1.2 Calculate the average radial load generated by each full turn of wire rope wound around the drum surface. : ② in, For the first Wire rope tension For the overall tension of the wire rope, The contact width between the wire rope and the rope groove; 3-2. For areas where the wire rope is not wrapped in a full loop: Calculate the average radial load generated by a non-full loop of wire rope wound on the drum surface. for: ③ in, The angle between the tension direction of the non-full loop wire rope and the normal direction of the drum. For non-full loop steel wire rope winding angle; 3-3. For contact areas with deflection angles: When there is an angular deviation at the wire rope entry point, the average radial load on the drum. for: ④ in, The angle at which the wire rope enters the rope. This refers to the winding angle of the wire rope within the area affected by the deflection angle. Let be the normal component of the wire rope tension and ; When there is an angle at the wire rope entry point, the average axial load on the drum. for: ⑤ 3-4. The loads calculated using formulas ②, ③, ④, and ⑤ are used as load inputs for the three-dimensional geometric model in the finite element analysis software to obtain the simulated stress field of the roller.

3. The method for predicting the stress field of a wound permanent magnet external rotor hoist drum according to claim 2, characterized in that, Step four includes the following specific steps: 4-1. Divide a complete operation process of a wound permanent magnet external rotor hoist into: For each discrete operating state, the simulated stress field of the roller under each discrete operating state is obtained using step three. Simulated stress field of the roller under discrete operating conditions , Given the number of spatial nodes for each discrete operating state, the stress fields of the m discrete operating states are finally constructed into a nodal stress field matrix. ,Right now ⑥ 4-2. Use intrinsic mode decomposition to obtain the modal basis functions and modal coefficients that can characterize the simulated stress field under arbitrary discrete operating conditions of the drum; Intrinsic mode decomposition formula middle, Let be a left singular vector matrix, whose column vectors are modal basis functions. It is a diagonal singular value matrix, and the magnitude of the singular values ​​reflects the energy contribution of each mode; Let be the right singular vector matrix, representing the direction of the corresponding mode coefficients. Select the first... After each mode, the mode coefficient matrix The stress field is approximated by combining the intrinsic mode decomposition formula: ⑦ in, For the previous truncation The mode matrix of the first-order modal basis functions.

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