Space mechanism wear life evaluation method

Abstract

The application discloses a kind of space mechanism wear life evaluation methods, comprising: step S1, the three-dimensional simulation model of space mechanism is established, and the simulation result is obtained using three-dimensional simulation model to carry out the mechanical simulation of space mechanism under standard motion state and gravity environment;Step S2, the stress state of multiple connection nodes on space mechanism is determined based on simulation result, and the wear condition of connection node under standard motion state and gravity environment is predicted based on stress state;Step S3, the wear life of space mechanism as a whole is evaluated based on the wear condition of multiple connection nodes and the evaluation result is obtained.By the application, the remaining use times of connection node under specific motion state or motion state combination can be quickly predicted for any kind of space mechanism.

Description

Technical Field

[0001] This invention belongs to the field of wear mechanics modeling and analysis technology, specifically relating to a method for evaluating the wear life of space mechanisms. Background Technology

[0002] A mechanism is a system composed of two or more parts, which can be rigid or elastic. Common mechanism components include shafts, gears, chains, cranks, connecting rods, sliders, cams, and rocker arms. These parts are connected together by connectors (such as bolts, pins, and bearings) to form a complete mechanism. A mechanism is a device that enables the completion of specific motion tasks. Mechanisms are an important component of mechanical systems, converting input motion and force into output motion and force, thereby realizing the various functions of the mechanical system.

[0003] Mechanisms can be classified according to their structure and function. Based on structure, mechanisms can be divided into planar mechanisms, spatial mechanisms, and hybrid mechanisms. Based on function, mechanisms can be divided into transmission mechanisms, conversion mechanisms, and control mechanisms. Spatial mechanisms refer to mechanisms in which parts move in three-dimensional space, such as universal joint mechanisms and spherical rocker mechanisms.

[0004] Due to the complexity of the connections of space mechanisms, the process of analyzing the overall wear and tear life of space mechanisms has become extremely complicated. In this process, staff not only need to consider the motion state of the space mechanism, but also the changes in the forces at various locations of the space mechanism during the state change process, and evaluate the wear and tear life of the space mechanism based on the changes in the forces. This process is relatively difficult to achieve. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose a method for evaluating the wear life of space mechanisms, so as to quickly predict the remaining number of uses of the connection nodes of any space mechanism based on a specific motion state or combination of motion states.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a method for evaluating the wear life of a space mechanism, comprising: Step S1: Establish a three-dimensional simulation model of the space mechanism, and use the three-dimensional simulation model to perform mechanical simulation of the space mechanism under standard motion state and gravity environment to obtain simulation results; Step S2: Determine the stress state of multiple connection nodes on the space mechanism based on the simulation results, and predict the wear of the connection nodes under standard motion state and gravity environment based on the stress state. Step S3: Evaluate the overall wear life of the space mechanism based on the wear of multiple connection nodes and obtain the evaluation results.

[0007] Preferably, step S1 includes: Establish a three-dimensional simulation model of the space mechanism and set model parameters for the three-dimensional simulation model, including volume parameters and mass parameters; Set the gravity environment of the actual use scenario corresponding to the space mechanism, and adjust the gravity parameters and gravity direction applied to the three-dimensional simulation model based on the gravity environment to form a simulated gravity environment; The standard motion state of the three-dimensional simulation model is determined, and the motion simulation of the spatial mechanism under simulated gravity environment is carried out based on the standard motion state. At the same time, the force state of each connection node during the motion simulation process is recorded as the simulation result.

[0008] Preferably, in the process of simulating the motion of a space mechanism under simulated gravity based on standard motion states, the recorded simulation results include the magnitude and direction of the collision and friction forces generated inside the connecting mechanism at the connecting nodes, wherein the connecting mechanism includes bearings, gears and threaded rods.

[0009] Preferably, step S2 includes: Based on the simulation results, the force state information of any connection node on the space mechanism during a complete standard motion is determined. Based on the force state information, the force duration and force situation of each force point on the connection node are statistically analyzed to obtain the first type of force situation of a single force point during a complete standard motion. Based on the first type of stress condition and the preset stress point wear calculation model, the wear state of the stress point after one complete standard motion process is calculated. The calculation formula is as follows: In the formula, This indicates the wear depth at the point of force application after one complete standard motion cycle. This represents the preset dimensionless wear coefficient. This represents the percentage of the ball's sliding distance at the point of force application; when the point of force application is sufficiently small, it is represented as 0 or 1. This represents a preset correction constant. This indicates the contact and collision force between the shaft and bearing components inside the connection node. Indicates the normal collision contact force. This represents tangential friction. Indicates the hardness of the softer material in the contacting pair; Specifically, a nonlinear equivalent spring-damped model is used to calculate the normal collision contact force. This normal collision contact force between the contacting parties is decomposed into two parts: the elastic force generated by mutual shearing and the damping force generated by relative velocity. The results are as follows: in, The contact stiffness coefficient determined by the Hertz formula model, The normal penetration depth is expressed as the point of force application. Indicates a nonlinear exponent. Indicates the damping coefficient. Indicates the puncture speed; Based on the Coulomb friction model, the magnitude of the tangential friction force is designed as follows: in, The relative sliding speed between the shaft and bearing components inside the connection node. The shear slip velocity function is expressed as follows: in, It is expressed as the coefficient of kinetic friction. Represents a symbolic function. Indicates the static friction coefficient. This is the critical velocity at which kinetic friction is at its maximum. This is the critical velocity at which static friction is at its maximum. Based on the wear state of the stress point after a complete standard motion process, a finite element analysis model of the connection node is constructed to simulate the wear process of the connection node. The model structure is adjusted in real time to update the collision coefficient of the positioning boundary node and the stress point. After the update, the wear state after the next complete standard motion process is predicted. Through continuous updates and iterations, the wear depth of each stress point on the connection node is calculated: in, This represents the total wear depth at the point of application after j+1 complete standard motion cycles. This represents the total wear depth at the stress point after j complete standard motion cycles. This represents the wear depth generated during j+1 complete standard motion cycles; The wear condition of the connection node is determined based on the wear depth of each stress point on the connection node.

[0010] Preferably, step S3 includes: Calculate the remaining service life of the connection node based on the wear depth of each of the multiple stress points on the connection node; The minimum remaining service life is determined based on the remaining service life of all connection nodes on the space mechanism. The wear life of the space mechanism as a whole was evaluated based on the minimum remaining service life, and the evaluation results were obtained.

[0011] Preferably, the remaining service life of the connection node is calculated based on the wear depth of each of the multiple stress points on the connection node, including: The wear depth of the t-th stress point on the connection node after x iterations is determined as follows. The service life Y of the connection node is calculated based on the wear depth and a preset wear threshold. Where Z represents the total number of iterations. This indicates the total number of force-bearing points on the connection node. This represents the maximum contact force at the t-th point of application during one complete standard motion. This represents the sum of the maximum contact forces at all points of force application during one complete standard motion. This represents the correction factor. This represents the preset first type of wear threshold. This indicates the preset second type of wear threshold; Based on the lifetime Y of the connecting node and the determined number of complete standard movements already performed, the remaining number of complete standard movements to be performed by the connecting node is calculated and used as the remaining lifetime.

[0012] The present invention has achieved at least the following beneficial effects: 1. It can quickly predict the remaining number of uses of the connection nodes of any kind of space mechanism based on a specific motion state or combination of motion states.

[0013] 2. A three-dimensional simulation model of the space mechanism was constructed, and the force state of each connection node was obtained in the simulated motion process, which closely resembles the actual use environment.

[0014] 3. The number of complete standard motions for the remaining connected nodes was calculated.

[0015] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0016] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration: Figure 1 This is a flowchart illustrating the steps of a method for evaluating the wear life of a space mechanism in an embodiment of the present invention. Figure 2 This is a flowchart illustrating the steps involved in simulating a space mechanism in an embodiment of the present invention. Detailed Implementation

[0017] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0018] The present invention provides a method for evaluating the wear life of space mechanisms, referring to... Figure 1 ,include: Step S1: Establish a three-dimensional simulation model of the space mechanism, and use the three-dimensional simulation model to perform mechanical simulation of the space mechanism under standard motion state and gravity environment to obtain simulation results; Step S2: Determine the stress state of multiple connection nodes on the space mechanism based on the simulation results, and predict the wear of the connection nodes under standard motion and gravity environment based on the stress state. Step S3: Evaluate the overall wear life of the space mechanism based on the wear of multiple connection nodes and obtain the evaluation results.

[0019] The working principle and beneficial effects of the above technical solution are as follows: During the use of a space mechanism, the parts most likely to affect its service life or most easily damaged are the connection nodes (or connecting joints, connecting mechanisms) of the space mechanism. This invention establishes a three-dimensional simulation model of the space mechanism by determining the space mechanism for which wear life evaluation is required, and then uses the three-dimensional simulation model to perform mechanical simulation of the space mechanism under standard motion state and gravity environment to obtain simulation results. The so-called mechanical simulation of the space mechanism under standard motion state and gravity environment can be the mechanical simulation of the space mechanism throughout its entire life cycle, including but not limited to the space mechanism performing one or more extension and contraction movements at a specific position angle, and the space mechanism performing one or more periodically changing position angles. The simulation involves multiple extension and contraction movements, etc. (This paper mainly simulates the mechanical simulation of a space mechanism performing a specific standard motion under a specific orientation angle, based on the fixed extension and contraction mode of existing aerospace extension-contraction mechanisms such as solar sails. This simulation does not represent a simulation applicable only to a space mechanism performing a specific standard motion under a specific orientation angle.) Based on the simulation results, the stress state of multiple connection nodes on the space mechanism is determined, and the wear of the connection nodes under standard motion and gravity environments is predicted based on the stress state. Thus, the wear state of each connection node after one standard motion is calculated and predicted based on the simulation results. Finally, the overall wear life of the space mechanism is evaluated based on the wear of multiple connection nodes, and the evaluation result is obtained. This achieves mechanical simulation of the space structure, determines the stress state of each connection node in the actual use of the space mechanism according to the change of the space structure's motion mode, calculates the wear of the connection nodes based on this stress state, and finally evaluates the life of the space mechanism based on the wear of the connection nodes. Through this invention, the remaining number of uses of connection nodes of any space mechanism under a specific motion state or combination of motion states can be quickly predicted.

[0020] In a preferred embodiment, refer to Figure 2 Step S1 includes: Step S11: Establish a three-dimensional simulation model of the space mechanism and set model parameters for the three-dimensional simulation model, including volume parameters and mass parameters; Step S12: Set the gravity environment of the actual use scenario corresponding to the space mechanism, and adjust the gravity parameters and gravity direction applied to the three-dimensional simulation model based on the gravity environment to form a simulated gravity environment; Step S13: Determine the standard motion state of the three-dimensional simulation model, and perform motion simulation of the spatial mechanism under simulated gravity environment based on the standard motion state. At the same time, record the force state on each connection node during the motion simulation process as the simulation result.

[0021] The working principle and beneficial effects of the above technical solution are as follows: A three-dimensional simulation model of the space mechanism is established, and model parameters are set for the three-dimensional simulation model, including but not limited to volume parameters and mass parameters; the gravity environment of the actual use scenario corresponding to the space mechanism is set, and the gravity parameters and gravity direction applied to the three-dimensional simulation model are adjusted based on the gravity environment to form a simulated gravity environment; the standard motion state of the three-dimensional simulation model is determined, and the motion simulation of the space mechanism under the simulated gravity environment is performed based on the standard motion state, while recording the force state at each connection node during the motion simulation process as the simulation result. Through this embodiment of the invention, a three-dimensional simulation model of the space mechanism is constructed, and the force state at each connection node in the simulated motion simulation process is obtained, closely resembling the actual use environment.

[0022] In a preferred embodiment, during the motion simulation of the space mechanism under simulated gravity based on standard motion states, the recorded simulation results include the magnitude and direction of the collision and friction forces generated inside the connecting mechanism at the connecting node, wherein the connecting mechanism includes bearings, gears, and threaded rods.

[0023] The working principle and beneficial effects of the above technical solution are as follows: During the motion simulation process, the mechanical characteristics of the connection node are obtained in detail by recording the simulation results, including the magnitude and direction of the collision and friction forces generated inside the connection mechanism on the connection node, which facilitates the calculation of the remaining life of the connection node.

[0024] In a preferred embodiment, step S2 includes: Based on the simulation results, the force state information of any connection node on the space mechanism during a complete standard motion is determined. Based on the force state information, the force duration and force situation of each force point on the connection node are statistically analyzed to obtain the first type of force situation of a single force point during a complete standard motion. Based on the first type of stress condition and the preset stress point wear calculation model, the wear state of the stress point after one complete standard motion process is calculated. The calculation formula is as follows: In the formula, This indicates the wear depth at the point of force application after one complete standard motion cycle. This represents the preset dimensionless wear coefficient. This represents the percentage of the ball's sliding distance at the point of force application, i.e., the distance L represented by the ball bearing within the range of the force application point during its movement. Taking a ball bearing as an example, it represents the distance L for a specific range of force application points, where the distance J is the sliding distance of the ball. Therefore, s = J / L. When the force application point is sufficiently small (i.e., the ball bearing is infinitely divided into multiple force application points, and the range of each force application point is sufficiently small), it is represented as 0 or 1. This represents a preset correction constant (the correction constant represents the damage to the ball bearing even when it is rolling throughout the entire process; the damage may be small but it does not mean there is no damage. This also prevents the result of no damage from occurring when s is zero). This indicates the contact and collision force between the shaft and bearing components inside the connection node. Indicates the normal collision contact force. This represents tangential friction. Indicates the hardness of the softer material in the contacting pair; Specifically, a nonlinear equivalent spring-damped model is used to calculate the normal collision contact force. This normal collision contact force between the contacting parties is decomposed into two parts: the elastic force generated by mutual shearing and the damping force generated by relative velocity. The results are as follows: in, The contact stiffness coefficient determined by the Hertz formula model, The normal penetration depth is expressed as the point of force application. Indicates a nonlinear exponent. Indicates the damping coefficient. Indicates the puncture speed; Based on the Coulomb friction model, the magnitude of the tangential friction force is designed as follows: in, The relative sliding speed between the shaft and bearing components inside the connection node. The shear slip velocity function is expressed as follows: in, It is expressed as the coefficient of kinetic friction. Represents a symbolic function. Indicates the static friction coefficient. The critical velocity at which kinetic friction is at its maximum. This is the critical velocity at which static friction is at its maximum. Based on the wear state of the stress point after a complete standard motion process, a finite element analysis model of the connection node is constructed to simulate the wear process of the connection node. The model structure is adjusted in real time to update the collision coefficient of the positioning boundary node and the stress point. After the update, the wear state after the next complete standard motion process is predicted. Through continuous updates and iterations, the wear depth of each stress point on the connection node is calculated: in, This represents the total wear depth at the point of application after j+1 complete standard motion cycles. This represents the total wear depth at the stress point after j complete standard motion cycles. This represents the wear depth generated during j+1 complete standard motion cycles; The wear condition of the connection node is determined based on the wear depth of each stress point on the connection node.

[0025] The working principle and beneficial effects of the above technical solution are as follows: After determining the stress state of the connection node, the first type of stress condition is determined for any stress point during a complete standard motion process. This first type of stress condition includes, but is not limited to, the intensity of force in each direction, the duration of force application, and the number of stresses. Based on this first type of stress condition, a stress point wear calculation model is used to calculate the wear state of the stress point after a complete standard motion process. Each wear will cause minor damage to the bearing model. The bearing model is adjusted based on this damage, and subsequent wear state calculations are performed. Through continuous updates and iterations, the wear depth of each stress point on the connection node is finally calculated. Based on the wear depth of each stress point on the connection node, the wear condition of the connection node is determined. This enables the prediction of the lifespan of the connection node based on the number of complete standard motions.

[0026] In a preferred embodiment, step S3 includes: Calculate the remaining service life of the connection node based on the wear depth of each of the multiple stress points on the connection node; The minimum remaining service life is determined based on the remaining service life of all connection nodes on the space mechanism. The wear life of the space mechanism as a whole was evaluated based on the minimum remaining service life, and the evaluation results were obtained.

[0027] The working principle and beneficial effects of the above technical solution are as follows: The remaining service life of the connecting nodes is calculated by measuring the wear depth of each of the multiple stress points on the connecting nodes; the minimum remaining service life is determined based on the remaining service life of all connecting nodes on the space mechanism; and the overall wear life of the space mechanism is evaluated based on the minimum remaining service life, yielding an evaluation result. This allows for the evaluation of the overall wear life of the space mechanism based on the remaining service life of multiple connecting nodes, and the acquisition of an evaluation result.

[0028] In a preferred embodiment, calculating the remaining service life of the connection node based on the wear depth of each of the multiple stress points on the connection node includes: The wear depth of the t-th stress point on the connection node after x iterations is determined as follows. The service life Y of the connection node is calculated based on the wear depth and a preset wear threshold. Where Z represents the total number of iterations. This indicates the total number of force-bearing points on the connection node. This represents the maximum contact force at the t-th point of application during one complete standard motion. This represents the sum of the maximum contact forces at all points of force application during one complete standard motion. This represents the correction factor. This represents the preset first type of wear threshold. This indicates the preset second type of wear threshold; Based on the lifetime Y of the connecting node and the determined number of complete standard movements already performed, the remaining number of complete standard movements to be performed by the connecting node is calculated and taken as the remaining lifetime.

[0029] The working principle and beneficial effects of the above technical solution are as follows: In the process of calculating the remaining service life of the connection node based on the wear depth of each of the multiple stress points on the connection node, the wear depth of the t-th stress point on the connection node after x iterations is set as... The service life Y of the connection node is calculated based on the wear depth and a preset wear threshold. The service life Y is primarily the remaining number of uses, expressed as follows: 1. For all stress points on the connection node, determine the wear depth obtained from multiple iterations of the stress point calculation, and calculate the wear degree of the stress point based on its weight (wherein, the weight of the stress point is determined by the ratio between the maximum contact force of the stress point in one complete standard motion process and the sum of the maximum contact forces of all stress points in one complete standard motion process). This determines the overall wear degree of the connection node after Z iterations, ensuring that this wear degree is maintained. 1. When the wear depth is not higher than the preset first type of wear threshold, the maximum value of Z is taken to ensure that the predicted remaining service life is maximized; 2. When the wear depth of any stress point on the connection node is greater than the preset second type of wear threshold after multiple iterations, the minimum number of iterations Z for that connection node is taken to ensure that the connection node reaches the minimum scrapping standard; 3. The minimum value of the two iterations Z is taken as the service life Y of the connection node. Finally, based on the service life Y of the connection node and the determined number of complete standard movements already performed, the remaining number of complete standard movements of the connection node is calculated and taken as the remaining service life. Through the embodiments of the present invention, the calculation of the remaining number of complete standard movements of the connection node is realized.

[0030] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for evaluating the wear life of a space mechanism, characterized in that, include: Step S1: Establish a three-dimensional simulation model of the space mechanism, and use the three-dimensional simulation model to perform mechanical simulation of the space mechanism under standard motion state and gravity environment to obtain simulation results; Step S2: Determine the stress state of multiple connection nodes on the space mechanism based on the simulation results, and predict the wear of the connection nodes under standard motion and gravity environment based on the stress state. Step S3: Evaluate the overall wear life of the space mechanism based on the wear of multiple connection nodes and obtain the evaluation results; Step S2 includes: Based on the simulation results, the force state information of any connection node on the space mechanism during a complete standard motion is determined. Based on the force state information, the force duration and force situation of each force point on the connection node are statistically analyzed to obtain the first type of force situation of a single force point during a complete standard motion. Based on the first type of stress condition and the preset stress point wear calculation model, the wear state of the stress point after one complete standard motion process is calculated. The calculation formula is as follows: In the formula, This indicates the wear depth at the point of force application after one complete standard motion cycle. This represents the preset dimensionless wear coefficient. This represents the percentage of the ball's sliding distance at the point of force application; when the point of force application is sufficiently small, it is represented as 0 or 1. This represents a preset correction constant. This indicates the contact and collision force between the shaft and bearing components inside the connection node. Indicates the normal collision contact force. This represents tangential friction. Indicates the hardness of the softer material in the contacting pair; Specifically, a nonlinear equivalent spring-damped model is used to calculate the normal collision contact force. This normal collision contact force between the contacting parties is decomposed into two parts: the elastic force generated by mutual shearing and the damping force generated by relative velocity. The results are as follows: in, The contact stiffness coefficient determined by the Hertz formula model, The normal penetration depth is expressed as the point of force application. Indicates a nonlinear exponent. Indicates the damping coefficient. Indicates the puncture speed; Based on the Coulomb friction model, the magnitude of the tangential friction force is designed as follows: in, The relative sliding speed between the internal shaft and bearing components of the connecting node. The shear slip velocity function is expressed as follows: in, It is expressed as the coefficient of kinetic friction. Represents a symbolic function. Indicates the static friction coefficient. This is the critical velocity at which kinetic friction is at its maximum. This is the critical velocity at which static friction is at its maximum. Based on the wear state of the stress point after a complete standard motion process, a finite element analysis model of the connection node is constructed to simulate the wear process of the connection node. The model structure is adjusted in real time to update the collision coefficient of the positioning boundary node and the stress point. After the update, the wear state after the next complete standard motion process is predicted. Through continuous updates and iterations, the wear depth of each stress point on the connection node is calculated: in, This represents the total wear depth at the point of application after j+1 complete standard motion cycles. This represents the total wear depth at the stress point after j complete standard motion cycles. This represents the wear depth generated during j+1 complete standard motion cycles; The wear condition of the connection node is determined based on the wear depth of each stress point on the connection node.

2. The method for evaluating the wear life of a space mechanism according to claim 1, characterized in that, Step S1 includes: Establish a three-dimensional simulation model of the space mechanism and set model parameters for the three-dimensional simulation model, including volume parameters and mass parameters; Set the gravity environment of the actual use scenario corresponding to the space mechanism, and adjust the gravity parameters and gravity direction applied to the three-dimensional simulation model based on the gravity environment to form a simulated gravity environment; The standard motion state of the three-dimensional simulation model is determined, and the motion simulation of the spatial mechanism under simulated gravity environment is carried out based on the standard motion state. At the same time, the force state of each connection node during the motion simulation process is recorded as the simulation result.

3. The method for evaluating the wear life of a space mechanism according to claim 2, characterized in that, In the simulation of the motion of a space mechanism under simulated gravity based on standard motion states, the recorded simulation results include the magnitude and direction of the collision and friction forces generated inside the connecting mechanism at the connection node. The connecting mechanism includes bearings, gears, and threaded rods.

4. The method for evaluating the wear life of a space mechanism according to claim 1, characterized in that, Step S3 includes: Calculate the remaining service life of the connection node based on the wear depth of each of the multiple stress points on the connection node; The minimum remaining service life is determined based on the remaining service life of all connection nodes on the space mechanism. The wear life of the space mechanism as a whole was evaluated based on the minimum remaining service life, and the evaluation results were obtained.

5. The method for evaluating the wear life of a space mechanism according to claim 4, characterized in that, The calculation of the remaining service life of the connection node based on the wear depth of each of the multiple stress points on the connection node includes: The wear depth of the t-th stress point on the connection node after x iterations is determined as follows. The service life Y of the connection node is calculated based on the wear depth and a preset wear threshold. Where Z represents the total number of iterations. This indicates the total number of force-bearing points on the connection node. This represents the maximum contact force at the t-th point of application during one complete standard motion. This represents the sum of the maximum contact forces at all points of force application during one complete standard motion. This represents the correction factor. This represents the preset first type of wear threshold. This indicates the preset second type of wear threshold; Based on the lifetime Y of the connecting node and the determined number of complete standard movements already performed, the remaining number of complete standard movements to be performed by the connecting node is calculated and used as the remaining lifetime.

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