Method and system for distributing contact pressure of movable and stationary contacts of a micro relay

Abstract

The application provides a contact pressure distribution method and system for micro relays, and relates to the technical field of control, which comprises the following steps: obtaining contact system state information, establishing a contact micro-element force-displacement response characteristic, identifying a stress concentration area, adjusting a driving force application path of a moving contact to redistribute contact pressure, and generating a segmented motion control instruction based on a fatigue life constraint. The application can effectively reduce the stress concentration phenomenon on the contact surface, optimize the contact pressure distribution, prolong the service life of the contact, and improve the reliability of the relay.

Description

Technical Field

[0001] This invention relates to the field of control technology, and in particular to a method and system for distributing contact pressure between moving and stationary contacts of a miniature relay. Background Technology

[0002] As a core switching element in electronic control systems, the reliability of miniature relays directly affects the stable operation of the entire system. In miniature relays, the contact quality between the moving and stationary contacts is a key factor determining their performance and lifespan. The distribution of contact pressure not only affects the contact resistance but is also closely related to wear, electrolytic corrosion, and mechanical fatigue of the contact materials. Traditional miniature relays typically use spring mechanisms or electromagnetic drives to establish contact between the moving and stationary contacts, achieving the circuit switching function. With the trend towards miniaturization and integration of electronic devices, the size of miniature relays continues to decrease, while the requirements for operational reliability continue to increase, posing greater challenges to the design and control of contact systems.

[0003] Current miniature relay contact pressure distribution technology suffers from the following main drawbacks: First, existing technologies struggle to accurately capture the actual pressure distribution at the contact interface, often employing macroscopic average pressure in their design. This neglects the uneven pressure distribution at the microscopic scale, potentially leading to excessive stress concentration in localized areas and accelerating contact material fatigue failure. Second, current moving contact driving methods typically utilize constant force or simple linear variations, lacking adaptive control capabilities for different contact stages. They cannot dynamically adjust driving parameters based on the actual contact state of the contact surface, hindering optimized contact pressure distribution. Third, current contact process control focuses primarily on the final contact state, neglecting the dynamic characteristics during contact formation. This fails to effectively suppress bounce and impact wear during contact, impacting relay lifespan and reliability. Summary of the Invention

[0004] The present invention provides a method and system for distributing contact pressure between moving and stationary contacts of a miniature relay, which can solve the problems in the prior art.

[0005] A first aspect of the present invention provides a method for distributing contact pressure between moving and stationary contacts of a miniature relay, comprising:

[0006] The contact system status information of the miniature relay is obtained. Based on the displacement of the moving contact and the deformation of the stationary contact in the contact system status information, the miniature relay is divided into multiple contact micro-elements, and the force-displacement response characteristics of each contact micro-element are established. The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system status information to obtain the initial contact pressure distribution.

[0007] Based on the initial contact pressure distribution, stress concentration areas on the contact surface are identified, and the spatial location features and stress gradient features corresponding to the stress concentration areas are extracted.

[0008] Based on the spatial location characteristics and stress gradient characteristics, the initial contact pressure distribution is redistributed by adjusting the driving force application path of the moving contact to obtain the target contact pressure distribution;

[0009] Based on the target contact pressure distribution and the fatigue life constraints of the contact material, segmented motion control commands for the moving contact are generated. These segmented motion control commands specify the speed variation law and pressure loading sequence of the moving contact at different stages of the contact stroke.

[0010] The segmented motion control command is sent to the drive mechanism to control the drive mechanism to drive the moving contact to complete the contact process with the stationary contact according to the segmented motion control command.

[0011] Based on the moving contact displacement and stationary contact deformation in the contact system state information, the miniature relay is divided into multiple contact micro-elements, and the force-displacement response characteristics of each contact micro-element are established. These force-displacement response characteristics are then correlated and mapped with the contact resistance in the contact system state information to obtain the initial contact pressure distribution, including:

[0012] Based on the displacement of the moving contact and the deformation of the stationary contact in the contact system state information, the normal distance distribution between the moving contact surface and the stationary contact surface is calculated to obtain the gap field of the contact interface;

[0013] The region in the gap field with a gap value of zero is taken as the actual contact region, and the actual contact region is divided into multiple contact micro-elements;

[0014] For each contact element, a constitutive relationship is established between the local stress tensor and the local strain tensor of that contact element. This constitutive relationship determines the deformation response of the contact element under three-dimensional stress state based on the elastic modulus and Poisson's ratio of the contact material.

[0015] Based on the constitutive relation, a virtual normal displacement load is applied to each contact element, and the normal and tangential reaction forces generated by the contact element under the virtual normal displacement load are calculated to obtain the force-displacement response characteristics of each contact element.

[0016] The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system state information to establish a coupling relationship between the contact pressure distribution and the conductive contact area;

[0017] Based on the coupling relationship, and using the measured contact resistance between the contacts as the boundary condition, the normal pressure value of each contact micro-element that satisfies the boundary condition is solved in reverse to obtain the initial contact pressure distribution.

[0018] Based on the initial contact pressure distribution, stress concentration regions on the contact surface are identified, and the spatial location features and stress gradient features corresponding to the stress concentration regions are extracted, including:

[0019] The normal pressure values ​​of each contact element in the initial contact pressure distribution are converted into normal stress values ​​to construct the stress field distribution on the contact surface; the spatial derivative of the normal stress values ​​of each contact element in the stress field distribution is performed to obtain the stress spatial gradient at the location of each contact element.

[0020] When the spatial stress gradient of a contact element exceeds the gradient statistical threshold, the contact element is marked as a stress concentration element; spatially adjacent stress concentration elements are clustered to form stress concentration element clusters, and each stress concentration element cluster corresponds to a stress concentration region;

[0021] For each stress concentration region, the average coordinates of the stress concentration micro-elements within that region are calculated to obtain the geometric center coordinates. The coordinate sequence of the stress concentration micro-elements located at the edge is identified to form the boundary contour. The geometric center coordinates are combined with the boundary contour to obtain the spatial location features corresponding to the stress concentration region.

[0022] For each stress concentration region, the rate of change of stress value with spatial distance is extracted from multiple radial paths extending towards the boundary contour starting from the geometric center coordinates of the stress concentration region. The stress gradient vector field of the stress concentration region is synthesized, and the gradient magnitude corresponding to the maximum principal direction is extracted as the stress gradient feature corresponding to the stress concentration region.

[0023] Based on the spatial location characteristics and stress gradient characteristics, the initial contact pressure distribution is redistributed by adjusting the driving force application path of the moving contact, resulting in a target contact pressure distribution including:

[0024] Based on the spatial location characteristics, the geometric center coordinates of each stress concentration region are extracted and positioned in the contact surface coordinate system.

[0025] Based on the stress gradient characteristics, the stress concentration region with the largest stress gradient amplitude is identified as the dominant stress concentration region, and the maximum principal direction of the stress gradient vector field of the dominant stress concentration region is extracted as the principal direction of stress concentration.

[0026] The opposite direction of the main stress concentration direction is determined as the stress release direction. Using the geometric center coordinates as the target point, the driving force application path of the moving contact is obtained by tracing back along the stress release direction to the position of the driving force application point.

[0027] According to the driving force application path, adjust the contact posture between the moving contact and the stationary contact so that the moving contact moves towards the stationary contact along the driving force application path under the action of the driving force;

[0028] Based on the adjusted contact posture, each contact element is re-divided, and the normal pressure value of the contact element under the adjusted contact posture is calculated according to the constitutive relation, thus obtaining the redistributed contact pressure distribution;

[0029] The redistributed contact pressure distribution is taken as the target contact pressure distribution.

[0030] Based on the target contact pressure distribution and the fatigue life constraints of the contact material, the segmented motion control commands for the moving contact are generated as follows:

[0031] Based on the target contact pressure distribution, the normal pressure value of each contact micro-element in the target contact pressure distribution is extracted; based on the normal pressure value and the area of ​​the contact micro-element, the contact stress value of each contact micro-element is calculated;

[0032] The contact stress value of each contact micro-element is compared with the fatigue strength limit of the contact material. Contact micro-elements with contact stress values ​​exceeding the fatigue strength limit are identified as fatigue risk micro-elements, and the distribution density of fatigue risk micro-elements on the contact surface is statistically analyzed.

[0033] Based on the stress-life curve of the contact material, a mapping relationship between contact stress value and fatigue cycle number is established;

[0034] Based on the mapping relationship and the contact stress value of each contact element, the allowable number of fatigue cycles for each contact element under the current contact stress level is calculated; the minimum value among the allowable number of fatigue cycles for all contact elements is determined as the fatigue life constraint value of the contact system.

[0035] Based on the distribution density of the fatigue risk micro-element and the fatigue life constraint value, the complete motion stroke of the moving contact is divided into multiple stages, and a corresponding segmented motion control command is set for each stage.

[0036] The complete motion stroke of the moving contact is divided into multiple stages, and corresponding segmented motion control commands are set for each stage, including:

[0037] The complete motion stroke includes the pre-contact phase, the contact establishment phase, and the steady-state contact phase. The pre-contact phase corresponds to the stage where the moving contact moves from a stationary position toward the stationary contact but before contact occurs. The contact establishment phase corresponds to the stage from the initial contact between the moving and stationary contacts to the establishment of the target contact pressure distribution. The steady-state contact phase corresponds to the stage where the target contact pressure distribution remains stable.

[0038] For the contact front section, a constant speed motion command is generated to control the moving contact to move towards the stationary contact at a preset approach speed;

[0039] For the contact establishment section, the velocity decay curve of the contact establishment section is calculated based on the distribution density of the fatigue risk micro-element. The velocity decay curve describes the process of the moving contact velocity gradually decreasing from the preset approach velocity to zero. A variable speed motion command is generated to control the moving contact to move according to the velocity decay curve.

[0040] For the steady-state contact section, the upper limit of the duration of the steady-state contact section is calculated based on the fatigue life constraint value, and a motion holding command is generated to control the moving contact to maintain the contact state with the stationary contact within the upper limit of the duration;

[0041] The constant speed motion command, the variable speed motion command, and the hold motion command are combined in sequence to obtain the segmented motion control command for the moving contact.

[0042] A second aspect of the present invention provides a contact pressure distribution system for the moving and stationary contacts of a miniature relay, comprising:

[0043] The first unit is used to acquire the contact system status information of the miniature relay. Based on the moving contact displacement and stationary contact deformation in the contact system status information, the miniature relay is divided into multiple contact micro-elements, and the force-displacement response characteristics of each contact micro-element are established. The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system status information to obtain the initial contact pressure distribution.

[0044] The second unit is used to identify stress concentration areas on the contact surface based on the initial contact pressure distribution, and to extract the spatial location features and stress gradient features corresponding to the stress concentration areas.

[0045] The third unit is used to redistribute the initial contact pressure distribution based on the spatial location characteristics and stress gradient characteristics by adjusting the driving force application path of the moving contact, thereby obtaining the target contact pressure distribution;

[0046] The fourth unit is used to generate segmented motion control commands for the moving contact based on the target contact pressure distribution and the fatigue life constraints of the contact material. The segmented motion control commands specify the speed change law and pressure loading sequence of the moving contact at different stages of the contact stroke.

[0047] The fifth unit is used to send the segmented motion control command to the drive mechanism, and control the drive mechanism to drive the moving contact to complete the contact process with the stationary contact according to the segmented motion control command.

[0048] A third aspect of the embodiments of the present invention,

[0049] An electronic device is provided, comprising:

[0050] processor;

[0051] Memory used to store processor-executable instructions;

[0052] The processor is configured to invoke instructions stored in the memory to execute the aforementioned method.

[0053] Fourth aspect of the present invention,

[0054] A computer-readable storage medium is provided, having stored thereon computer program instructions that, when executed by a processor, implement the aforementioned method.

[0055] The beneficial effects of this application are as follows:

[0056] By acquiring the state information of the contact system and establishing the micro-element force-displacement response characteristics, the precise analysis of contact pressure is realized, making the stress distribution of the contact visible and quantifiable, thus overcoming the problem that traditional methods are difficult to accurately characterize the pressure distribution of complex contact interfaces.

[0057] Based on the identified stress concentration area characteristics, the path of the driving force applied to the moving contact is intelligently adjusted, which realizes the uniform redistribution of contact pressure, effectively reduces stress concentration in local areas, extends the service life of the contacts, and improves the reliability of the relay.

[0058] By adopting a segmented motion control strategy, refined motion commands for the moving contacts are generated based on the fatigue life constraints of the contact materials. This optimizes the speed change and pressure loading sequence of the moving contacts during the contact process, reduces contact impact damage, improves the electrical and mechanical life of the relay, and reduces contact bounce. Attached Figure Description

[0059] Figure 1 This is a schematic flowchart illustrating the contact pressure distribution method for the moving and stationary contacts of a miniature relay according to an embodiment of the present invention.

[0060] Figure 2 A flowchart is generated for the segmented motion control instructions of the moving contact. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0063] Figure 1 This is a schematic flowchart illustrating the contact pressure distribution method for the moving and stationary contacts of a miniature relay according to an embodiment of the present invention. Figure 1 As shown, the method includes:

[0064] The contact system status information of the miniature relay is obtained. Based on the displacement of the moving contact and the deformation of the stationary contact in the contact system status information, the miniature relay is divided into multiple contact micro-elements, and the force-displacement response characteristics of each contact micro-element are established. The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system status information to obtain the initial contact pressure distribution.

[0065] Based on the initial contact pressure distribution, stress concentration areas on the contact surface are identified, and the spatial location features and stress gradient features corresponding to the stress concentration areas are extracted.

[0066] Based on the spatial location characteristics and stress gradient characteristics, the initial contact pressure distribution is redistributed by adjusting the driving force application path of the moving contact to obtain the target contact pressure distribution;

[0067] Based on the target contact pressure distribution and the fatigue life constraints of the contact material, segmented motion control commands for the moving contact are generated. These segmented motion control commands specify the speed variation law and pressure loading sequence of the moving contact at different stages of the contact stroke.

[0068] The segmented motion control command is sent to the drive mechanism to control the drive mechanism to drive the moving contact to complete the contact process with the stationary contact according to the segmented motion control command.

[0069] In one optional implementation, based on the moving contact displacement and stationary contact deformation in the contact system state information, the miniature relay is divided into multiple contact micro-elements, and the force-displacement response characteristics of each contact micro-element are established. These force-displacement response characteristics are then correlated and mapped with the contact resistance in the contact system state information to obtain the initial contact pressure distribution, including:

[0070] Based on the displacement of the moving contact and the deformation of the stationary contact in the contact system state information, the normal distance distribution between the moving contact surface and the stationary contact surface is calculated to obtain the gap field of the contact interface;

[0071] The region in the gap field with a gap value of zero is taken as the actual contact region, and the actual contact region is divided into multiple contact micro-elements;

[0072] For each contact element, a constitutive relationship is established between the local stress tensor and the local strain tensor of that contact element. This constitutive relationship determines the deformation response of the contact element under three-dimensional stress state based on the elastic modulus and Poisson's ratio of the contact material.

[0073] Based on the constitutive relation, a virtual normal displacement load is applied to each contact element, and the normal and tangential reaction forces generated by the contact element under the virtual normal displacement load are calculated to obtain the force-displacement response characteristics of each contact element.

[0074] The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system state information to establish a coupling relationship between the contact pressure distribution and the conductive contact area;

[0075] Based on the coupling relationship, and using the measured contact resistance between the contacts as the boundary condition, the normal pressure value of each contact micro-element that satisfies the boundary condition is solved in reverse to obtain the initial contact pressure distribution.

[0076] For example, the contact system state information is acquired, including parameters such as moving contact displacement, stationary contact deformation, and contact resistance. For instance, for a typical miniature relay, the moving contact displacement is 15 μm, the stationary contact deformation is 3 μm, and the initial contact resistance is 20 mΩ. Based on this state information, the normal distance distribution between the moving and stationary contact surfaces is calculated, yielding the gap field at the contact interface. This calculation can be achieved by performing point-to-point distance calculations between the moving and stationary contact surfaces in a common coordinate system. For example, within a 100 μm × 100 μm contact area, 5000 × 5000 grid points can be established, and the perpendicular distance between the two surfaces can be calculated for each grid point, forming the gap field matrix.

[0077] Based on the calculated gap field, the region with a gap value of zero is determined as the actual contact area. In practical applications, considering measurement errors and numerical calculation accuracy, gap values ​​smaller than 0.01 μm can be considered zero. For example, in the above calculation, it was found that the gap value within a range of approximately 30 μm × 30 μm in the central region is less than the threshold; this region can be determined as the actual contact area.

[0078] The actual contact area is divided into multiple contact micro-elements. In this embodiment, the contact area can be uniformly divided into 5μm × 5μm square micro-elements, forming approximately 36 contact micro-elements. For each contact micro-element, a constitutive relationship between the local stress tensor and the local strain tensor of that contact micro-element is established. This constitutive relationship determines the deformation response of the contact micro-element under three-dimensional stress state based on the elastic modulus and Poisson's ratio of the contact material. For example, for gold contact materials, its elastic modulus is 78 GPa and its Poisson's ratio is 0.42, based on which an isotropic linear elastic constitutive relationship can be established.

[0079] After establishing the constitutive relation, a virtual normal displacement load is applied to each contact element. The normal and tangential reactions generated by the contact element under the virtual normal displacement load are calculated to obtain the force-displacement response characteristics of each contact element. Specifically, different displacement loads of 0.1 μm, 0.2 μm, and 0.3 μm can be applied to each element sequentially, and the corresponding reaction force responses are recorded. For example, for a typical element in the central region, the normal reaction force generated when a 0.1 μm displacement is applied is 1.2 mN, and when a 0.2 μm displacement is applied, the normal reaction force increases to 2.5 mN.

[0080] Based on the force-displacement response characteristics of each contact element obtained above, the contact force generated by each element under a given displacement can be derived. According to contact mechanics theory, the contact force F of an element is directly proportional to the contact pressure P of that element: P = F / S, where S is the area of ​​the element. Simultaneously, according to electrical contact theory, the actual conductive contact area A is directly proportional to the contact pressure P: A = k × P, where k is the material correlation coefficient, which can be obtained by k = π / (4H), and H is the hardness of the contact material. For gold contact materials (hardness approximately 1000 MPa), k is approximately 0.00025 mm. 2 / N. Furthermore, the resistance Ri of the infinitesimal element is inversely proportional to its conductive contact area A: Ri = ρ / A, where ρ is the contact resistivity. Through this series of relationships, the mapping from force-displacement response characteristics to contact resistance is realized, and a complete coupling relationship between contact pressure distribution and conductive contact area is established.

[0081] Based on the aforementioned coupling relationship, using the measured contact resistance between the contacts as boundary conditions, the normal pressure value of each contact element satisfying the boundary conditions is solved in reverse to obtain the initial contact pressure distribution. Specifically, let the total contact resistance be R. According to the principle of parallel circuits, the resistance Ri of each contact element is inversely proportional to the conductive contact area Ai of that element: Ri = ρ / Ai, where ρ is the contact resistivity. The parallel value of the resistances of each element should be equal to the total resistance R. Through iterative optimization algorithms, the pressure distribution of each element that makes the total resistance equal to the measured value can be solved.

[0082] For example, for the aforementioned miniature relay, the measured contact resistance is 20 mΩ. By reverse engineering, the normal pressure of the central region's micro-element is approximately 10 MPa, and the normal pressure of the edge region's micro-element is approximately 5 MPa. The pressure distribution across the entire contact area exhibits a characteristic of high pressure at the center and low pressure at the edges, which is consistent with actual contact conditions. This pressure distribution can serve as the initial condition for subsequent dynamic contact analysis, providing a basis for accurately predicting the relay's contact performance.

[0083] This invention accurately calculates the normal distance distribution between moving and stationary contacts, divides the actual contact area into micro-elements, and establishes constitutive relations, thus accurately reflecting the true contact state of the contact interface. By calculating virtual normal displacement loads and inversely solving for measured contact resistance values, a coupling relationship between pressure distribution and conductive area is established, making the initial contact pressure distribution more accurate and providing a reliable foundation for subsequent optimization.

[0084] In one optional implementation, identifying stress concentration regions on the contact surface based on the initial contact pressure distribution, and extracting the spatial location features and stress gradient features corresponding to the stress concentration regions, includes:

[0085] The normal pressure values ​​of each contact element in the initial contact pressure distribution are converted into normal stress values ​​to construct the stress field distribution on the contact surface; the spatial derivative of the normal stress values ​​of each contact element in the stress field distribution is performed to obtain the stress spatial gradient at the location of each contact element.

[0086] When the spatial stress gradient of a contact element exceeds the gradient statistical threshold, the contact element is marked as a stress concentration element; spatially adjacent stress concentration elements are clustered to form stress concentration element clusters, and each stress concentration element cluster corresponds to a stress concentration region;

[0087] For each stress concentration region, the average coordinates of the stress concentration micro-elements within that region are calculated to obtain the geometric center coordinates. The coordinate sequence of the stress concentration micro-elements located at the edge is identified to form the boundary contour. The geometric center coordinates are combined with the boundary contour to obtain the spatial location features corresponding to the stress concentration region.

[0088] For each stress concentration region, the rate of change of stress value with spatial distance is extracted from multiple radial paths extending towards the boundary contour starting from the geometric center coordinates of the stress concentration region. The stress gradient vector field of the stress concentration region is synthesized, and the gradient magnitude corresponding to the maximum principal direction is extracted as the stress gradient feature corresponding to the stress concentration region.

[0089] For example, after obtaining the initial contact pressure distribution of a miniature relay, it is necessary to further identify stress concentration areas on the contact surface and extract key features of these areas to provide a basis for subsequent pressure redistribution. For each contact micro-element in the initial contact pressure distribution, its normal pressure value P divided by the actual contact area S of that micro-element yields the normal stress value σ = P / S. For example, for a micro-element with an area of ​​25 μm... 2 If the normal pressure value of a micro-element is 0.25 mN, the calculated normal stress value is 10 MPa. In this way, the normal pressure values ​​of all contact micro-elements are converted into corresponding normal stress values, forming a complete stress field distribution on the contact surface.

[0090] Spatial differentiation is performed on the normal stress values ​​of each contact element in the constructed stress field distribution using the central difference method. For a contact element with position coordinates (x, y), the component of its stress spatial gradient in the x-direction is calculated as G. x =(σ(x+Δx,y)-σ(x-Δx,y)) / (2Δx), where the component in the y-direction is calculated as G. y =(σ(x,y+Δy)-σ(x,y-Δy)) / (2Δy), where Δx and Δy are the distances between adjacent infinitesimal elements in the x and y directions, respectively, and are taken as the side lengths of the infinitesimal elements, for example, 5 μm. Combining the gradient components in the x and y directions, the magnitude G of the stress spatial gradient at the location of this infinitesimal element can be obtained. This magnitude is equal to the square root of the sum of the squares of the gradient components in the x and y directions. This spatial differentiation operation is performed on all contact infinitesimal elements on the contact surface, generating a complete stress gradient field.

[0091] After the stress gradient field is generated, stress concentration regions are identified. The gradient statistical threshold is determined based on the statistical characteristics of the global stress gradient distribution. The average stress gradient values ​​of all contact micro-elements are added to twice the standard deviation as the gradient statistical threshold. For example, assuming the average stress gradient of all contact micro-elements is 0.5 MPa / μm and the standard deviation is 0.2 MPa / μm, the gradient statistical threshold is set to 0.9 MPa / μm. Contact micro-elements with stress gradients exceeding 0.9 MPa / μm are marked as stress concentration micro-elements.

[0092] Clustering of spatially adjacent stress-concentrated micro-elements is implemented using a distance-based region growing algorithm. Starting with any unclassified stress-concentrated micro-element, it is set as a seed point. Micro-elements within its surrounding eight neighborhoods are examined. If a neighboring micro-element is also a stress-concentrated micro-element, it is added to the current cluster and used as a new seed point to continue expansion. When further expansion is impossible, a micro-element cluster is formed, corresponding to a stress-concentrated region. This process is repeated for the remaining unclassified stress-concentrated micro-elements until all stress-concentrated micro-elements are assigned to a cluster. In practical applications, a minimum cluster size threshold can be set, such as 3 micro-elements; clusters smaller than this threshold are considered noise and ignored.

[0093] For each stress concentration region, the x-coordinate of the center point is obtained by summing the x-coordinates of all stress concentration elements within the region and dividing by the total number of elements. Similarly, the y-coordinate of the center point is obtained by summing the y-coordinates of all stress concentration elements within the region and dividing by the total number of elements. This determines the geometric center of the stress concentration region. Simultaneously, a stress concentration element at the edge is defined as one that has at least one directly adjacent element that does not belong to the current stress concentration region. By examining the neighborhood state of each stress concentration element, edge elements can be identified, and their coordinates can be arranged in a clockwise or counterclockwise direction to form a closed boundary profile. Combining the geometric center coordinates with the boundary profile yields the spatial location characteristics of the stress concentration region.

[0094] For each stress concentration region, the rate of change of stress value with spatial distance is extracted from multiple radial paths extending towards the boundary contour from the geometric center coordinates of that region. Specifically, starting from the geometric center, multiple radial lines are extended at different angles, typically 15° or 30° intervals, forming a total of 12 or 24 radial paths. Along each radial path, stress values ​​are sampled at a fixed step size (e.g., 1 μm), and the ratio of the stress difference between adjacent sampling points to the distance is calculated to obtain the rate of change of stress along that path. The rate of change is calculated by dividing the stress difference between adjacent sampling points by the distance between those two points, where the difference in stress values ​​between the previous and next sampling points is the numerator, and the sampling step size between the two points is the denominator, yielding the rate of change of stress along that path.

[0095] Based on the stress change rate along each radial path, a stress gradient vector field is synthesized for the stress concentration region. In polar coordinates, the stress change rate along each radial path corresponds to a gradient component at a specific angle. Combining these components yields the gradient vector field distribution for the entire stress concentration region. The maximum principal direction, i.e., the direction with the largest gradient magnitude, is then identified from the gradient vector field. Specifically, the average magnitude of the gradient along each radial path is calculated, and the angle corresponding to the path with the largest magnitude is determined; this angle is the maximum principal direction. The gradient magnitude corresponding to the maximum principal direction is extracted as the stress gradient characteristic of the stress concentration region. For example, if the average gradient magnitude at 45° is 1.2 MPa / μm, and this is the maximum value among all radial paths, then 45° is the maximum principal direction, and 1.2 MPa / μm is the stress gradient characteristic value of the stress concentration region.

[0096] This invention accurately identifies stress concentration regions by converting normal pressure into stress values ​​and calculating spatial gradients. Through clustering to form micro-clusters and extracting geometric features, combined with radial path analysis and principal direction gradient extraction, it achieves precise localization and feature quantification of stress concentration regions.

[0097] In one optional implementation, based on the spatial location characteristics and stress gradient characteristics, the initial contact pressure distribution is redistributed by adjusting the driving force application path of the moving contact, resulting in a target contact pressure distribution including:

[0098] Based on the spatial location characteristics, the geometric center coordinates of each stress concentration region are extracted and positioned in the contact surface coordinate system.

[0099] Based on the stress gradient characteristics, the stress concentration region with the largest stress gradient amplitude is identified as the dominant stress concentration region, and the maximum principal direction of the stress gradient vector field of the dominant stress concentration region is extracted as the principal direction of stress concentration.

[0100] The opposite direction of the main stress concentration direction is determined as the stress release direction. Using the geometric center coordinates as the target point, the driving force application path of the moving contact is obtained by tracing back along the stress release direction to the position of the driving force application point.

[0101] According to the driving force application path, adjust the contact posture between the moving contact and the stationary contact so that the moving contact moves towards the stationary contact along the driving force application path under the action of the driving force;

[0102] Based on the adjusted contact posture, each contact element is re-divided, and the normal pressure value of the contact element under the adjusted contact posture is calculated according to the constitutive relation, thus obtaining the redistributed contact pressure distribution;

[0103] The redistributed contact pressure distribution is taken as the target contact pressure distribution.

[0104] For example, after obtaining the spatial location and stress gradient characteristics of the stress concentration areas on the contact surface, it is necessary to adjust the driving force application path of the moving contact based on these characteristics to achieve a redistribution of contact pressure. The contact surface coordinate system is defined as a Cartesian coordinate system with the center of the contact surface as the origin and parallel to the contact surface. The geometric center coordinates of each stress concentration area are obtained through the aforementioned calculation, and these coordinate data are stored in a position information array. The position information array is a two-dimensional array, with each row containing the identifier of a stress concentration area and the coordinate value of its geometric center. For a typical miniature relay contact system, 3 to 5 stress concentration areas are identified, with their geometric center coordinates located at different positions on the contact surface. For example, within a 100μm × 100μm contact area, the geometric center of a primary stress concentration area is located at coordinates (35μm, 42μm), and another secondary concentration area is located at (-20μm, -15μm).

[0105] The stress gradient amplitudes of each stress concentration region are compared, and the region with the largest amplitude is selected as the dominant stress concentration region. The comparison of stress gradient amplitudes uses a direct numerical comparison method without setting a threshold. For example, assuming three stress concentration regions are detected with stress gradient amplitudes of 1.2 MPa / μm, 0.8 MPa / μm, and 0.5 MPa / μm, the first region (1.2 MPa / μm) is selected as the dominant stress concentration region. The maximum principal direction, i.e., the angle in which the gradient vector points, is extracted from the stress gradient vector field data of this dominant region. This angle is represented in polar coordinates, with the positive x-axis of the contact surface coordinate system as 0° and counterclockwise rotation as positive. For example, the maximum principal direction of the dominant stress concentration region is 135°, indicating that the pressure gradient is largest from the origin to the upper left.

[0106] The stress release direction differs from the principal stress concentration direction by 180°. If the principal stress concentration direction is 135°, then the stress release direction is 315° (or -45°). Starting from the geometric center coordinates, a straight line is extended along the stress release direction. The intersection of this line and the feasible driving area of ​​the moving contact is the recommended location for the driving force. The feasible driving area is typically the edge region of the moving contact or a specially designed driving force receiving structure. The driving force application path is defined as a straight path from this location to the geometric center coordinates. This path is represented by the starting coordinates, ending coordinates, and path direction angle. For the aforementioned example, if the geometric center coordinates of the dominant stress concentration area are (35μm, 42μm), the stress release direction is 315°, and the boundary of the feasible driving area of ​​the moving contact is located at the intersection of the straight line and the coordinates (-25μm, -18μm), then the starting point of the driving force application path is (-25μm, -18μm), the ending point is (35μm, 42μm), and the path direction angle is 135°.

[0107] Based on the determined driving force application path, contact posture adjustment includes two parts: position offset and angle deflection of the moving contact. Position offset refers to the relative displacement of the moving contact center with respect to the stationary contact center, while angle deflection refers to the adjustment of the angle between the moving contact plane and the stationary contact plane. The specific adjustment method depends on the relay's structural type. For planar miniature relays, position offset can be achieved by fine-tuning the moving contact's support structure or the position of the driving electrode; for rotary miniature relays, angle deflection can be achieved by adjusting the shaft position or the limiting structure. The adjustment amount is determined by the direction and length of the driving force application path, typically ranging from 1μm to 5μm in position offset and from 0.1° to 0.5° in angle deflection. In the aforementioned example, based on the driving force application path, the moving contact center needs to be offset by 3μm in the 135° direction, and the moving contact plane needs to be rotated counterclockwise by 0.2° around an axis perpendicular to the 135° direction.

[0108] The contact elements are re-divided using the same mesh size and method as the initial subdivision, but based on the adjusted contact orientation. Typically, the element size is maintained at 5μm × 5μm to ensure computational consistency. For each newly subdivided contact element, the previously established constitutive relation is applied to calculate the normal pressure value of that element under the new orientation. The calculation process considers the elastic deformation characteristics of the material and the influence of surface roughness. For the gold contact material, its elastic modulus is 78 GPa and its Poisson's ratio is 0.42. The virtual displacement method is used in the calculation; a virtual displacement corresponding to the contact depth is applied to each contact element, and the corresponding normal reaction force is solved through the constitutive relation. Dividing this normal reaction force by the element area yields the normal pressure value. For example, under the adjusted contact orientation, a 20% reduction in the contact depth of an element originally in a stress concentration region causes its normal pressure value to decrease from 10 MPa to approximately 6 MPa; while in areas with insufficient contact, a 30% increase in contact depth increases the normal pressure value from 2 MPa to approximately 4 MPa.

[0109] The redistributed contact pressure distribution is taken as the target contact pressure distribution, which is stored in the form of a two-dimensional matrix, with the matrix size consistent with the micro-element division of the contact area. For example, for a 5×5 micro-element division, a 20×20 pressure distribution matrix is ​​formed within a 100μm×100μm contact area. Each element in this matrix represents the normal pressure value of the corresponding micro-element, in MPa. This pressure distribution can be converted into a heat map using visualization technology, visually displaying the pressure distribution. Ideally, the target contact pressure distribution should exhibit relatively uniform characteristics, with the ratio of the maximum to minimum pressure value not exceeding 3:1. For example, before adjustment, the pressure distribution reached 12 MPa in the dominant stress concentration area, while the edge area only had 1 MPa. After adjustment, the target distribution shows pressure values ​​between 3 MPa and 9 MPa throughout the contact area, significantly improving pressure uniformity. The evaluation index for pressure uniformity can be the ratio of the pressure standard deviation to the mean, i.e., the coefficient of variation. The coefficient of variation of the target contact pressure distribution should typically be less than 0.5, while the coefficient of variation before adjustment is as high as 0.8 or greater.

[0110] This invention realizes the redistribution of contact pressure between moving and stationary contacts of a miniature relay based on stress analysis, which effectively improves the uniformity of contact pressure distribution, reduces local stress concentration, and thus extends the service life of the contact system.

[0111] In one optional implementation, based on the target contact pressure distribution and the fatigue life constraints of the contact material, the segmented motion control command for the moving contact includes:

[0112] Based on the target contact pressure distribution, the normal pressure value of each contact micro-element in the target contact pressure distribution is extracted; based on the normal pressure value and the area of ​​the contact micro-element, the contact stress value of each contact micro-element is calculated;

[0113] The contact stress value of each contact micro-element is compared with the fatigue strength limit of the contact material. Contact micro-elements with contact stress values ​​exceeding the fatigue strength limit are identified as fatigue risk micro-elements, and the distribution density of fatigue risk micro-elements on the contact surface is statistically analyzed.

[0114] Based on the stress-life curve of the contact material, a mapping relationship between contact stress value and fatigue cycle number is established;

[0115] Based on the mapping relationship and the contact stress value of each contact element, the allowable number of fatigue cycles for each contact element under the current contact stress level is calculated; the minimum value among the allowable number of fatigue cycles for all contact elements is determined as the fatigue life constraint value of the contact system.

[0116] Based on the distribution density of the fatigue risk micro-element and the fatigue life constraint value, the complete motion stroke of the moving contact is divided into multiple stages, and a corresponding segmented motion control command is set for each stage.

[0117] Combination Figure 2 The flowchart for generating segmented motion control commands for the moving contact is explained. When generating segmented motion control commands for the moving contact based on the target contact pressure distribution and the fatigue life constraints of the contact material, the stress state of the contact micro-element and the fatigue characteristics of the material need to be considered systematically. This process extracts the normal pressure value of each contact micro-element from the aforementioned target contact pressure distribution data. The target contact pressure distribution is stored in the form of a two-dimensional matrix, with each element of the matrix corresponding to the normal pressure value of a contact micro-element. The micro-element size is usually set to 5μm×5μm, which ensures both calculation accuracy and keeps the computational load within a reasonable range. Data extraction uses a matrix scanning method, traversing each element in the 20×20 pressure distribution matrix and reading the pressure value into the contact pressure array. This array adopts a planar array structure, with each element containing the coordinate index of the micro-element and the corresponding normal pressure value. For example, for the contact micro-element located at matrix coordinates (8,12), its normal pressure value is 6.5MPa, and this information is stored as a record.

[0118] Based on the extracted normal pressure value and the contact element area, for a contact element of constant size, its area is the square of the side length of the element, i.e., 25 μm. 2 The calculation of contact stress values ​​takes into account the microscopic characteristics of the contact interface, especially the influence of surface roughness. The actual contact area is usually smaller than the nominal contact area; therefore, a surface roughness correction factor is applied to adjust the calculation. This factor ranges from 0.6 to 0.9, depending on the surface processing technology and roughness grade of the contact point. For electropolished metal contact surfaces, the correction factor is typically 0.8. The contact stress value is equal to the normal pressure value divided by the area of ​​the micro-element, and then divided by the surface roughness correction factor. For example, for a micro-element with a normal pressure value of 6.5 MPa, the contact stress value is calculated as 6.5 / (25 × 10⁻⁶). -12 0.8 ÷ 0.8 = 325 MPa. The calculation accuracy is retained to 0.1 MPa, using rounding.

[0119] The fatigue strength limit is the maximum stress value at which a material can withstand infinite cyclic loading without fatigue failure; it is also known as the fatigue limit. For commonly used contact materials, such as silver alloys, the fatigue strength limit is approximately 150 MPa; for gold alloys, it is approximately 200 MPa; and for copper alloys, it is approximately 175 MPa. The identification of fatigue risk micro-elements uses a direct comparison method: if the contact stress value of a micro-element exceeds the fatigue strength limit of the material used, the micro-element is marked as a fatigue risk micro-element and recorded in the risk micro-element index array. The distribution density is calculated using a region division method. The contact surface is divided into 4×4 regions, and the number of fatigue risk micro-elements in each region is counted. This count is then divided by the total number of micro-elements in the region to obtain the fatigue risk micro-element density for that region. For example, if a region contains 25 micro-elements, of which 8 are fatigue risk micro-elements, then the fatigue risk micro-element density for that region is 32%.

[0120] The stress-life curve of the contact material is described using the Basquin equation, where the number of fatigue cycles equals the material coefficient multiplied by a negative power of the contact stress. The power is typically between 10 and 15, while the material coefficient depends on the specific contact material. For silver alloy contacts, the material coefficient is approximately 5 × 10⁻⁶. 30 The power is 12; for gold alloy contacts, the material coefficient is approximately 8 × 10⁻⁶. 32 The power is 13.5; for copper alloy contacts, the material coefficient is approximately 2 × 10⁻⁶. 31 The power is 12.5. This mapping relationship is implemented using a lookup table, which pre-calculates and stores the corresponding fatigue cycle counts for common stress levels, and uses linear interpolation to process intermediate values. The lookup table has a stress resolution of 5 MPa and covers a range from 50 MPa to 600 MPa. For example, for a gold alloy contact, a stress value of 325 MPa corresponds to approximately 7.2 × 10^5 fatigue cycles.

[0121] For each contact element, the corresponding number of fatigue cycles is obtained by querying a mapping table based on its contact stress value. The query follows a proximity principle; if the contact stress value falls between two entries, linear interpolation is used to calculate the corresponding number of fatigue cycles. For elements with stress values ​​below the fatigue strength limit, their allowable number of fatigue cycles is considered infinite, represented by a sufficiently large value in actual calculations, such as 1 × 10^12. The minimum value among the allowable number of fatigue cycles for all contact elements is determined as the fatigue life constraint value for the contact system. The search process for the minimum value excludes elements with extremely low contact pressures, as these elements may have abnormal fatigue life predictions due to numerical calculation errors. Specifically, a lower limit for contact pressure is set to 0.5 MPa, and only elements with pressures higher than this value are considered. For example, if the calculated minimum allowable number of fatigue cycles is 4.5 × 10^12... 5 Then, the fatigue life constraint value of the contact system is this value.

[0122] Based on the distribution density of fatigue risk elements and fatigue life constraints, the complete travel of the moving contact is divided into multiple stages. This division is based on the displacement of the moving contact from its initial position to its final contact position, which depends on the specific structure of the relay and is typically between 50 μm and 300 μm. The travel division adopts a risk density-oriented strategy, that is, the travel is divided into several stages according to the distribution density of fatigue risk elements. Areas with high risk density should use lower travel speeds and slower pressure loading rates for their corresponding travel segments. Typically, the travel is divided into three to five stages, with the length of each stage varying depending on the risk density distribution. If the risk density shows an increasing trend, the travel segments of subsequent stages should be shortened; if it shows a decreasing trend, the travel segments of subsequent stages can be appropriately lengthened.

[0123] The segmented motion control command includes four core parameters for each stage: start and end positions, motion speed, acceleration / deceleration characteristics, and pressure loading rate. The start and end positions are expressed as a percentage of displacement relative to the initial position; for example, 0%-30% for the first stage, 30%-70% for the second stage, and 70%-100% for the third stage. The motion speed parameter is in millimeters per second (mm / s) and is determined based on the fatigue risk density; the higher the risk density, the lower the speed setting. For example, for a low-risk area (density <10%), the speed can be set to 5 mm / s; for a medium-risk area (density 10%-30%), the speed is set to 2 mm / s; and for a high-risk area (density >30%), the speed is set to 0.5 mm / s. The acceleration / deceleration characteristics describe the speed change pattern, typically using a trapezoidal speed curve, i.e., a combination of uniform acceleration-uniform speed-uniform deceleration. The proportion of the acceleration / deceleration segment is set to 15% to 20% of the total stroke to smooth speed changes and reduce impact. The pressure loading rate parameter describes the rate of increase in contact pressure per unit time, in megapascals per second (MPa). The higher the risk density, the lower the pressure loading rate should be to slow down the rate of stress accumulation. Typical settings are: 100 MPa / s for low-risk areas, 50 MPa / s for medium-risk areas, and 20 MPa / s for high-risk areas.

[0124] The control commands are formatted as time series, specifying the position, velocity, and applied pressure of the moving contact at discrete time points. The time resolution is 1 millisecond, and the entire contact process typically spans between 50 and 200 milliseconds. Data is stored as a three-column time series: the first column is the timestamp, the second is the position value, the third is the velocity value, and the fourth is the pressure value. For example, at time t=15ms, the control command specifies a position of 45μm, a velocity of 2mm / s, and a pressure of 30MPa. The control commands are transmitted to the actuator via a communication interface. The actuator uses an interpolation algorithm to calculate the control parameters at intermediate moments, achieving smooth control. Communication uses RS-485 or CAN bus, with a data frame format of start identifier (1 byte), timestamp (4 bytes), position value (4 bytes), velocity value (4 bytes), pressure value (4 bytes), and checksum (2 bytes). The communication rate is set to 115200bps, sufficient to meet the millisecond-level control accuracy requirements.

[0125] This invention identifies fatigue-risk elements by calculating the stress values ​​of contact micro-elements and comparing them with the material fatigue strength, and establishes a stress-life mapping relationship to determine the fatigue life constraints of the contact system. This motion control strategy based on material properties and fatigue mechanisms can effectively prevent premature contact failure, extend the service life of relays, and improve the reliability and stability of the system.

[0126] In one optional implementation, the complete travel of the moving contact is divided into multiple stages, and corresponding segmented motion control commands are set for each stage, including:

[0127] The complete motion stroke includes the pre-contact phase, the contact establishment phase, and the steady-state contact phase. The pre-contact phase corresponds to the stage where the moving contact moves from a stationary position toward the stationary contact but before contact occurs. The contact establishment phase corresponds to the stage from the initial contact between the moving and stationary contacts to the establishment of the target contact pressure distribution. The steady-state contact phase corresponds to the stage where the target contact pressure distribution remains stable.

[0128] For the contact front section, a constant speed motion command is generated to control the moving contact to move towards the stationary contact at a preset approach speed;

[0129] For the contact establishment section, the velocity decay curve of the contact establishment section is calculated based on the distribution density of the fatigue risk micro-element. The velocity decay curve describes the process of the moving contact velocity gradually decreasing from the preset approach velocity to zero. A variable speed motion command is generated to control the moving contact to move according to the velocity decay curve.

[0130] For the steady-state contact section, the upper limit of the duration of the steady-state contact section is calculated based on the fatigue life constraint value, and a motion holding command is generated to control the moving contact to maintain the contact state with the stationary contact within the upper limit of the duration;

[0131] The constant speed motion command, the variable speed motion command, and the hold motion command are combined in sequence to obtain the segmented motion control command for the moving contact.

[0132] For example, dividing the complete travel of the moving contact into multiple stages and setting corresponding segmented motion control commands for each stage is a core technology for achieving high reliability and long lifespan in contact systems. The complete travel of the moving contact is subdivided into three main stages: the pre-contact stage, the contact establishment stage, and the steady-state contact stage. The pre-contact stage refers to the movement of the moving contact from its rest position towards the stationary contact before physical contact occurs. This stage typically accounts for 40%-60% of the total travel, with a distance range of 30μm to 150μm, depending on the size of the relay or switch. The contact establishment stage corresponds to the process from the initial contact between the moving and stationary contacts until the target contact pressure distribution is fully established. This stage is the most critical in the contact system, typically accounting for 30%-50% of the total travel, with a distance range of 15μm to 80μm. The steady-state contact stage refers to the stage where the target contact pressure distribution is fully established and remains stable. At this point, the moving contact remains in a specific position, ensuring a stable and continuous contact state to meet electrical connection requirements.

[0133] For the contact front section, the moving contact is controlled to move towards the stationary contact at a preset approach speed. This preset approach speed is a configurable parameter, typically ranging from 0.5 mm / s to 10 mm / s, with a default value of 3 mm / s. The selection of this speed value needs to consider several factors: for miniature relays, the approach speed should be set in a lower range, i.e., 0.5-2 mm / s; for medium-sized relays, a medium range, i.e., 2-5 mm / s; and for large relays, a higher range, i.e., 5-10 mm / s. The constant speed movement command is generated using a time-division sampling method, i.e., calculating the position sequence of the moving contact at fixed time intervals, typically 1 ms. Position calculation uses a linear interpolation method; the position value at each moment is equal to the initial position plus the product of speed and time. The data structure for a constant speed motion command includes a command type field with a value of 0x01, indicating a constant speed command; an initial position field, a 32-bit floating-point number in micrometers; a target position field, a 32-bit floating-point number in micrometers; a speed field, a 32-bit floating-point number in millimeters per second; and a motion direction field, with a value of 0x01 indicating forward and 0x02 indicating reverse.

[0134] For the contact establishment section, the velocity decay curve describes the process of the moving contact velocity gradually decreasing from a preset approach velocity to zero. The decay curve is calculated based on the spatial distribution characteristics of fatigue risk elements, using a partitioned weighted average method. The contact area is divided into multiple sub-regions, typically a 4×4 grid. The fatigue risk element density within each sub-region is calculated, and the corresponding velocity decay coefficient is determined based on the density value. The decay coefficient is directly proportional to the fatigue risk element density; the higher the density, the faster the decay. Specifically, the decay curve uses an exponential decay model, where the decay constant is determined by the fatigue risk element density. For regions with a risk density below 10%, the decay constant is 0.05; for regions with a risk density between 10% and 30%, the decay constant is 0.10; and for regions with a risk density above 30%, the decay constant is 0.20. The contact establishment section is typically divided into 10-20 discrete sampling points, each corresponding to a velocity value. The velocities between sampling points are calculated using linear interpolation.

[0135] Based on the calculated velocity decay curve, a variable speed motion command is generated to control the moving contact to move according to the curve. The data structure of the variable speed motion command includes a command type field (value 0x02, indicating a variable speed command); an initial position field (32-bit floating-point number); a velocity sequence length field (16-bit unsigned integer); and a velocity sequence field, composed of multiple velocity-displacement pairs. Each element in the velocity sequence contains a relative displacement value (16-bit signed integer, unit: micrometers) and a corresponding velocity value (16-bit signed integer, unit: micrometers per second). The execution of the variable speed command employs a piecewise acceleration control strategy, whereby the system calculates the required acceleration based on the current position and the target velocity, allowing the moving contact to smoothly transition to the target velocity. To ensure motion accuracy, the rate of change of acceleration, i.e., jerk, is limited to within 1000 mm / s³ to avoid mechanical shock and vibration.

[0136] For the steady-state contact section, the upper limit of the steady-state contact section duration is calculated based on the fatigue life constraint value. The fatigue life constraint value is the expected number of fatigue cycles of the contact system under the current contact pressure distribution, calculated in the previous process. The calculation of the upper limit of duration considers the fatigue accumulation effect and adopts the linear fatigue accumulation theory. The upper limit of duration is proportional to the fatigue life constraint value, but a safety factor must also be considered. Typically, the safety factor is taken as 2-5, with a higher safety factor suitable for applications requiring high reliability. For a fatigue life constraint value of 10⁶ cycles, if the rated contact time for each operation is 50 ms and the safety factor is 3, then the upper limit of duration is calculated as 10⁶ divided by 3 multiplied by 50 ms, approximately 16,667 seconds. Considering that the continuous contact time in practical applications rarely reaches the theoretical upper limit, the system usually sets a reasonable upper limit of time, such as 30-120 seconds. Exceeding this time will trigger a warning or protection mechanism.

[0137] Based on the calculated upper limit of duration, a hold motion command is generated. The data structure of the hold motion command includes a command type field (value 0x03, indicating a hold command); a position field (32-bit floating-point number, unit: micrometers); a hold time field (32-bit unsigned integer, unit: milliseconds); and a contact pressure field (16-bit unsigned integer, unit: kilopascals). During the execution of the hold command, the system monitors the contact pressure distribution in real time to ensure its stability. If a contact pressure fluctuation is detected to exceed a set threshold, typically ±10% of the rated pressure, the moving contact position is automatically adjusted for compensation. The compensation employs a proportional-integral control strategy, with a response time typically less than 5ms, to ensure rapid recovery of the contact state to stability.

[0138] Constant speed motion commands, variable speed motion commands, and holding motion commands are combined sequentially to generate complete segmented motion control commands for the moving contact. The command combination employs a sequential execution mechanism, establishing three consecutive execution phases: a pre-contact phase, a contact establishment phase, and a steady-state contact phase. Phase transitions are controlled by explicit triggering conditions; for example, the transition from the pre-contact phase to the contact establishment phase is triggered by a contact detection signal, which can be detected by resistance, photoelectric, or force sensors. Smooth transitions at phase junctions must be handled during command combination to avoid motion discontinuities caused by command switching. Smooth transitions are achieved through boundary parameter matching, ensuring the continuity of position, velocity, and acceleration at the boundaries between adjacent command phases. During execution, the control system first reads and executes the constant speed motion command until a contact signal is detected, then switches to the variable speed motion command to execute the contact establishment process. Once the moving contact reaches the target position, it switches to the holding motion command to maintain the contact state until the time limit is reached. Throughout the process, the system maintains the identifier variable of the current execution phase, the percentage of progress completed, and the start and end timestamps of each phase for operational status monitoring and anomaly handling.

[0139] Complete segmented motion control instructions are organized into instruction packets, containing an instruction header and multiple instruction segments. The instruction header includes an instruction packet identifier (32-bit integer); an instruction packet length (16-bit integer, in bytes); the number of instruction segments (8-bit integer); and a checksum (16-bit integer). Each instruction segment corresponds to a motion stage and is arranged in chronological order. Instruction packets are transmitted to the motion control execution unit via the system communication bus, using CAN or SPI communication protocols with a communication rate of at least 1 Mbps to ensure real-time instruction performance. Upon receiving the instructions, the motion control execution unit performs integrity verification and parameter boundary checks, and then executes each instruction segment according to the specified timing.

[0140] Taking a silver alloy contact as an example, the complete stroke is 100 μm, with the initial contact segment being 0-60 μm, the contact establishment segment being 60-90 μm, and the steady-state contact segment being 90-100 μm. The fatigue risk micro-element distribution density is: 15% in the initial contact establishment stage (60-70 μm), 28% in the middle stage (70-80 μm), and 38% in the later stage (80-90 μm). The fatigue life constraint value is 5 × 10^5 cycles. The generated segmented motion control commands are as follows: The initial contact segment uses a constant speed of 3 mm / s with a movement time of 20 ms; the contact establishment segment uses a variable speed command, with the speed gradually decreasing from 3 mm / s to 0 mm / s. The specific speed sequence is: 3 mm / s at 60 μm displacement, 2.5 mm / s at 65 μm, 1.8 mm / s at 70 μm, 1.2 mm / s at 75 μm, 0.7 mm / s at 80 μm, 0.3 mm / s at 85 μm, and 0 mm / s at 90 μm, with a movement time of approximately 50 ms; the steady-state contact segment uses a holding command, maintaining the contact at 90 μm for 60 seconds with a contact pressure of 250 kPa. The entire command package is 128 bytes long and contains 3 command segments.

[0141] During the execution of this segmented motion control command, a closed-loop control strategy is employed to ensure that the actual motion matches the command requirements. Position feedback utilizes a high-precision photoelectric encoder with a resolution of 0.1 μm; velocity feedback is calculated through position differentiation with a sampling frequency of 1 kHz; and pressure feedback employs a miniature pressure sensor array with an accuracy of 1 kPa. The control algorithm combines feedforward and feedback methods. Feedforward control pre-calculates the control input based on the system dynamics model, while feedback control adjusts according to the actual deviation. The system response time is less than 2 ms, position accuracy is better than ±0.5 μm, velocity accuracy is better than ±0.1 mm / s, and pressure accuracy is better than ±5 kPa.

[0142] This invention divides the movement of the moving contact into three stages and sets corresponding control commands. In particular, it employs a speed decay curve based on fatigue risk during the contact establishment stage, and controls the duration based on fatigue constraints during the steady-state contact stage. This segmented control strategy reduces contact impact, optimizes the stress distribution process, achieves precise control of dynamic pressure loading, and effectively improves contact life and relay reliability.

[0143] A second aspect of the present invention provides a contact pressure distribution system for the moving and stationary contacts of a miniature relay, the system comprising:

[0144] The first unit is used to acquire the contact system status information of the miniature relay. Based on the moving contact displacement and stationary contact deformation in the contact system status information, the miniature relay is divided into multiple contact micro-elements, and the force-displacement response characteristics of each contact micro-element are established. The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system status information to obtain the initial contact pressure distribution.

[0145] The second unit is used to identify stress concentration areas on the contact surface based on the initial contact pressure distribution, and to extract the spatial location features and stress gradient features corresponding to the stress concentration areas.

[0146] The third unit is used to redistribute the initial contact pressure distribution based on the spatial location characteristics and stress gradient characteristics by adjusting the driving force application path of the moving contact, thereby obtaining the target contact pressure distribution;

[0147] The fourth unit is used to generate segmented motion control commands for the moving contact based on the target contact pressure distribution and the fatigue life constraints of the contact material. The segmented motion control commands specify the speed change law and pressure loading sequence of the moving contact at different stages of the contact stroke.

[0148] The fifth unit is used to send the segmented motion control command to the drive mechanism, and control the drive mechanism to drive the moving contact to complete the contact process with the stationary contact according to the segmented motion control command.

[0149] A third aspect of the present invention provides an electronic device, comprising:

[0150] processor;

[0151] Memory used to store processor-executable instructions;

[0152] The processor is configured to invoke instructions stored in the memory to execute the aforementioned method.

[0153] A fourth aspect of the present invention provides a computer-readable storage medium having stored thereon computer program instructions that, when executed by a processor, implement the aforementioned method.

[0154] This invention can be a method, apparatus, system, and / or computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for performing various aspects of the invention.

[0155] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail 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; 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 of the present invention.

Claims

1. A method for distributing contact pressure between moving and stationary contacts of a miniature relay, characterized in that, include: The contact system state information of the miniature relay is obtained. Based on the moving contact displacement and stationary contact deformation in the contact system state information, the miniature relay is divided into multiple contact micro-elements, and the force-displacement response characteristics of each contact micro-element are established. The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system state information to obtain the initial contact pressure distribution, including: Based on the displacement of the moving contact and the deformation of the stationary contact in the contact system state information, the normal distance distribution between the moving contact surface and the stationary contact surface is calculated to obtain the gap field of the contact interface; The region in the gap field with a gap value of zero is taken as the actual contact region, and the actual contact region is divided into multiple contact micro-elements; For each contact element, a constitutive relationship is established between the local stress tensor and the local strain tensor of that contact element. This constitutive relationship determines the deformation response of the contact element under three-dimensional stress state based on the elastic modulus and Poisson's ratio of the contact material. Based on the constitutive relation, a virtual normal displacement load is applied to each contact element, and the normal and tangential reaction forces generated by the contact element under the virtual normal displacement load are calculated to obtain the force-displacement response characteristics of each contact element. The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system state information to establish a coupling relationship between the contact pressure distribution and the conductive contact area; Based on the coupling relationship, and using the measured contact resistance between the contacts as boundary conditions, the normal pressure value of each contact micro-element that satisfies the boundary conditions is solved in reverse to obtain the initial contact pressure distribution; Based on the initial contact pressure distribution, stress concentration areas on the contact surface are identified, and the spatial location features and stress gradient features corresponding to the stress concentration areas are extracted. Based on the spatial location characteristics and stress gradient characteristics, the initial contact pressure distribution is redistributed by adjusting the driving force application path of the moving contact to obtain the target contact pressure distribution; Based on the target contact pressure distribution and the fatigue life constraints of the contact material, segmented motion control commands for the moving contact are generated. These segmented motion control commands specify the speed variation law and pressure loading sequence of the moving contact at different stages of the contact stroke. The segmented motion control command is sent to the drive mechanism to control the drive mechanism to drive the moving contact to complete the contact process with the stationary contact according to the segmented motion control command.

2. The method according to claim 1, characterized in that, Based on the initial contact pressure distribution, stress concentration regions on the contact surface are identified, and the spatial location features and stress gradient features corresponding to the stress concentration regions are extracted, including: The normal pressure values ​​of each contact micro-element in the initial contact pressure distribution are converted into normal stress values ​​to construct the stress field distribution on the contact surface; By performing spatial differentiation on the normal stress value of each contact element in the stress field distribution, the spatial stress gradient at the location of each contact element is obtained; When the stress spatial gradient of a contact element exceeds the gradient statistics threshold, the contact element is marked as a stress concentration element. Spatially adjacent stress concentration elements are clustered to form stress concentration element clusters, and each stress concentration element cluster corresponds to a stress concentration region; For each stress concentration region, the average coordinates of the stress concentration micro-elements within that region are calculated to obtain the geometric center coordinates. The coordinate sequence of the stress concentration micro-elements located at the edge is identified to form the boundary contour. The geometric center coordinates are combined with the boundary contour to obtain the spatial location features corresponding to the stress concentration region. For each stress concentration region, the rate of change of stress value with spatial distance is extracted from multiple radial paths extending towards the boundary contour starting from the geometric center coordinates of the stress concentration region. The stress gradient vector field of the stress concentration region is synthesized, and the gradient magnitude corresponding to the maximum principal direction is extracted as the stress gradient feature corresponding to the stress concentration region.

3. The method according to claim 1, characterized in that, Based on the spatial location characteristics and stress gradient characteristics, the initial contact pressure distribution is redistributed by adjusting the driving force application path of the moving contact, resulting in a target contact pressure distribution including: Based on the spatial location characteristics, the geometric center coordinates of each stress concentration region are extracted and positioned in the contact surface coordinate system. Based on the stress gradient characteristics, the stress concentration region with the largest stress gradient amplitude is identified as the dominant stress concentration region, and the maximum principal direction of the stress gradient vector field of the dominant stress concentration region is extracted as the principal direction of stress concentration. The opposite direction of the main stress concentration direction is determined as the stress release direction. Using the geometric center coordinates as the target point, the driving force application path of the moving contact is obtained by tracing back along the stress release direction to the position of the driving force application point. According to the driving force application path, adjust the contact posture between the moving contact and the stationary contact so that the moving contact moves towards the stationary contact along the driving force application path under the action of the driving force; Based on the adjusted contact posture, each contact element is re-divided, and the normal pressure value of the contact element under the adjusted contact posture is calculated according to the constitutive relation, thus obtaining the redistributed contact pressure distribution; The redistributed contact pressure distribution is taken as the target contact pressure distribution.

4. The method according to claim 1, characterized in that, Based on the target contact pressure distribution and the fatigue life constraints of the contact material, the segmented motion control commands for the moving contact are generated as follows: Based on the target contact pressure distribution, extract the normal pressure value of each contact micro-element in the target contact pressure distribution; Based on the normal pressure value and the contact element area, the contact stress value of each contact element is calculated; The contact stress value of each contact micro-element is compared with the fatigue strength limit of the contact material. Contact micro-elements with contact stress values ​​exceeding the fatigue strength limit are identified as fatigue risk micro-elements, and the distribution density of fatigue risk micro-elements on the contact surface is statistically analyzed. Based on the stress-life curve of the contact material, a mapping relationship between contact stress value and fatigue cycle number is established; Based on the mapping relationship and the contact stress value of each contact element, the allowable number of fatigue cycles for each contact element under the current contact stress level is calculated; The minimum value among all allowable fatigue cycles for contact elements is determined as the fatigue life constraint value for the contact system; Based on the distribution density of the fatigue risk micro-element and the fatigue life constraint value, the complete motion stroke of the moving contact is divided into multiple stages, and a corresponding segmented motion control command is set for each stage.

5. The method according to claim 4, characterized in that, The complete motion stroke of the moving contact is divided into multiple stages, and corresponding segmented motion control commands are set for each stage, including: The complete motion stroke includes the pre-contact phase, the contact establishment phase, and the steady-state contact phase. The pre-contact phase corresponds to the stage where the moving contact moves from a stationary position toward the stationary contact but before contact occurs. The contact establishment phase corresponds to the stage from the initial contact between the moving and stationary contacts to the establishment of the target contact pressure distribution. The steady-state contact phase corresponds to the stage where the target contact pressure distribution remains stable. For the contact front section, a constant speed motion command is generated to control the moving contact to move towards the stationary contact at a preset approach speed; For the contact establishment section, the velocity decay curve of the contact establishment section is calculated based on the distribution density of the fatigue risk micro-element. The velocity decay curve describes the process of the moving contact velocity gradually decreasing from the preset approach velocity to zero. A variable speed motion command is generated to control the moving contact to move according to the velocity decay curve. For the steady-state contact section, the upper limit of the duration of the steady-state contact section is calculated based on the fatigue life constraint value, and a motion holding command is generated to control the moving contact to maintain the contact state with the stationary contact within the upper limit of the duration; The constant speed motion command, the variable speed motion command, and the hold motion command are combined in sequence to obtain the segmented motion control command for the moving contact.

6. A contact pressure distribution system for the moving and stationary contacts of a miniature relay, used to implement the method as described in any one of claims 1-5, characterized in that, include: The first unit is used to acquire the contact system status information of the miniature relay. Based on the moving contact displacement and stationary contact deformation in the contact system status information, the miniature relay is divided into multiple contact micro-elements, and the force-displacement response characteristics of each contact micro-element are established. The force-displacement response characteristics are correlated and mapped with the contact resistance in the contact system status information to obtain the initial contact pressure distribution. The second unit is used to identify stress concentration areas on the contact surface based on the initial contact pressure distribution, and to extract the spatial location features and stress gradient features corresponding to the stress concentration areas. The third unit is used to redistribute the initial contact pressure distribution based on the spatial location characteristics and stress gradient characteristics by adjusting the driving force application path of the moving contact, thereby obtaining the target contact pressure distribution; The fourth unit is used to generate segmented motion control commands for the moving contact based on the target contact pressure distribution and the fatigue life constraints of the contact material. The segmented motion control commands specify the speed change law and pressure loading sequence of the moving contact at different stages of the contact stroke. The fifth unit is used to send the segmented motion control command to the drive mechanism, and control the drive mechanism to drive the moving contact to complete the contact process with the stationary contact according to the segmented motion control command.

7. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to invoke instructions stored in the memory to execute the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the method described in any one of claims 1 to 5.

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