Automatic assembling method of radio frequency connector

Abstract

The invention discloses an automatic assembling method of a radio frequency connector, which comprises the following steps that: A, a female joint is static, and a male joint is translated to the upper part of the female joint and is in contact with the female joint; b, acquiring data of a force sensor to obtain contact force information between the male joint and the female joint, and performing filtering and tool gravity compensation on the data; c, inputting the processed force data into the KAN network to obtain a predicted position error between the male joint and the female joint; d, according to the position error, a first rotation center and a second rotation center of the two sections of rotation are calculated through a virtual rotation center algorithm, so that pose changes of the male connector after two times of rotation are obtained, and the speeds of two times of rotation movement of the male connector are obtained; e, inputting the processed force data into an admittance controller at the same time to obtain a compliant speed; f, the compliant speed and the two-time rotating speed are input into a speed controller, the final corresponding movement of the male connector and the speed and displacement of all joints needed by the robot are solved, and pose adjustment is completed; and G, pressing the male joint to complete assembly.

Description

Technical Field

[0001] This invention belongs to the field of 3C component assembly, and specifically relates to an automatic assembly method for radio frequency (RF) connectors. Background Technology

[0002] As a subclass of shaft-hole assembly, 3C assembly also uses male and female connectors as shaft holes for assembly. Conventional shaft-hole assembly methods mainly fall into two technical routes. One technical route analyzes the relationship between the force and attitude of the shaft through physical modeling. For example, existing technology A classifies the contact state of circular shaft holes and maps the force on the boundary conditions. It then uses the mapping relationship to propose a new compliant control algorithm to achieve shaft hole pose adjustment. In addition, this existing technology also models the assembly error of circular shaft holes and proposes a new adaptive controller to achieve a balance between time and force accuracy during pose adjustment.

[0003] Another technical approach is data-driven, which uses data on posture and force obtained from several experiments, or trains the intrinsic relationship through reinforcement learning, to complete the assembly task. For example, existing technology B uses a Gaussian mixture model to train the relationship between posture deviation angle and force during the assembly of circular shaft holes, thereby guiding the shaft to correct in the corresponding direction. Existing technology C, for the multi-axis hole assembly problem, uses hierarchical reinforcement learning to train a higher-order policy to output conditions for lower-order policies based on the state, and the lower-order policies output corresponding actions based on the state and conditions, that is, the posture adjustment actions of the shaft holes.

[0004] Due to the complex structure of 3C components, it is difficult to analyze the contact state of male and female connectors through physical modeling. Therefore, research on their assembly is mainly data-driven: Existing technology D conducts assembly research on BtB connectors in 3C connectors, and predicts the position and orientation of male and female connectors by measuring force data at various points on the assembly plane, thereby guiding the next step of orientation adjustment.

[0005] As can be seen from the existing technologies described above, conventional shaft-hole assemblies, with their simple shaft-hole structure, can establish the relationship between the shaft-hole contact state and physical quantities such as forces through physical modeling. However, 3C components are mostly complex in structure and small in shape, and their complex contact states may be difficult to fully cover by a model, making accurate physical modeling difficult. Training 3C component assembly models through data-driven methods encounters the following problems: First, 3C components have a rich variety of contact states, making it very difficult to measure the forces or other data under all contact states, inevitably affecting data coverage; second, training a complete assembly process through data has learning efficiency issues and low data utilization.

[0006] Therefore, providing an automated assembly method for radio frequency (RF) connectors that combines the advantages of the two aforementioned technical approaches has become a problem that the industry needs to solve. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the main objective of this invention is to provide an automated assembly method for radio frequency (RF) connectors, which enables male and female connectors to be assembled through certain posture adjustments even with initial positional errors.

[0008] To achieve the aforementioned main objectives, this invention discloses an automated assembly method for radio frequency (RF) connectors, used for automatically assembling male and female connectors of RF connectors. The assembly end of the female connector is cylindrical, and the assembly end of the male connector is correspondingly provided with a circular groove. After assembly, the cylinder is embedded within the circular groove. The automated assembly method includes the following steps:

[0009] A. (Contact Phase) The female connector remains stationary, while the male connector moves to above the female connector and makes contact with it.

[0010] B. Collect force sensor data to obtain contact force information between the male and female connectors, and filter and compensate for tool gravity on the data;

[0011] C. Input the processed force data into the KAN network to obtain the predicted positional error between the male and female connectors;

[0012] D. Based on the position error, the first and second rotation centers of the two rotations are calculated using the virtual rotation center algorithm, thereby obtaining the pose change of the male connector after the two rotations and calculating the speed of the male connector in the two rotations.

[0013] E. The processed force data is simultaneously input into the admittance controller to obtain the compliance velocity;

[0014] F. Input the compliant speed and the two rotational speeds into the speed controller to solve for the speed and displacement of each joint required by the robot to achieve the corresponding movement of the male connector, and complete the pose adjustment.

[0015] G. (Press and assemble) Press the male connector to complete the assembly.

[0016] The purpose of this invention is to enable RF connectors to achieve successful assembly by proposing a strategy to adjust their pose even when there is positioning error.

[0017] This invention combines the accuracy advantages of physical modeling with the data prediction capabilities of data-driven methods. Focusing on RF connectors in 3C components, it proposes a rotational adjustment strategy based on a Virtual Rotation Center (VRC) and a compliance and speed control strategy based on Admittance Velocity Control (AVC). VRC enables the RF connector to adjust its rotational pose around a specific point through network prediction. AVC compensates for potential positional errors during rotation through force compliance, maintaining contact between the male and female connectors while balancing rotational and compliance speeds to prevent damage from excessive accidental contact forces.

[0018] This invention relates to an assembly strategy for RF connectors. The proposed strategy enables male and female connectors to be assembled by adjusting their orientation even with initial positional errors. Details are as follows:

[0019] 1. RF Connector Male and Female Connector Contact State Analysis. The strategy proposed in this invention mainly revolves around the adjustment process of the connector before it is pressed and assembled. By listing and analyzing the contact states of the male and female connectors from single-point contact to multi-point contact, it was found that many different contact states correspond to the same force conditions, making it difficult to deduce the current contact state from the current contact force data. However, through analysis, it was discovered that in many contact states, the outer ring of the female connector is embedded in the grooves of the inner and outer rings of the male connector; this state is referred to as the slotting state. In the slotting state, the search range of the male connector is reduced, and the force is easily identified. Therefore, this invention designs an assembly adjustment strategy based on this state.

[0020] 2. Virtual Rotation Center. The male and female connectors initially contact each other in a parallel orientation. After stable contact, the positional error is predicted using a KAN network based on the current force on the male connector. Based on this positional error, the rotation center for the first rotation phase is calculated, and the rotation angle is specified. Ideally, at the end of the first rotation phase, the male and female connectors will be in a locked position. At this point, the rotation center for the second rotation phase is calculated, and the connectors are rotated in the opposite direction by the same angle to achieve a return-to-center effect. Finally, the male and female connectors reach a flush orientation, and assembly can be completed by pressing.

[0021] 3. Admittance Velocity Control. Due to positional errors in the predictions of the KAN network, these errors are divided into distance and angular errors. Angular errors cause an angle between the plane of rotation and the ideal assembly plane, resulting in unexpectedly excessive contact force during rotation. Distance errors directly affect the position of the male and female connectors after rotation. The admittance velocity control proposed in this invention compensates for these errors by setting a desired force along the horizontal direction to make the male connector compliant along this desired force. Simultaneously, since there is a certain sequential relationship between the compliant motion and the rotational motion, rotating before the compliant motion is complete can also easily lead to unexpected collisions. Therefore, this invention incorporates a speed controller to balance the two speeds, correspondingly reducing the rotational speed when the compliant speed is high.

[0022] According to a specific embodiment of the present invention, in step D, the two rotations are as follows:

[0023] In the first stage of rotation (slotting stage), the male connector rotates around the first rotation center in the vertical plane, causing the cylindrical end of the female connector to engage with the groove at the assembly end of the male connector, achieving the slotting state. At this time, the male connector is tilted.

[0024] In the second stage of rotation (alignment stage), the male connector rotates around the second rotation center in the vertical plane until the male connector is aligned with the female connector.

[0025] According to a specific embodiment of the present invention, step D, the method for determining the first rotation center includes the following steps:

[0026] D1. The connector transitions from a non-contact state to a constant force contact state;

[0027] D2. The KAN network makes a preliminary prediction of the positional error (distance error) between the male and female connectors;

[0028] D3. Calculate the distances from both ends of the male connector to the female connector based on the positional error;

[0029] D4. Calculate the position of the first center of rotation;

[0030] D5. Calculate the position of the male connector after rotating a specific angle around the first rotation center, and guide the robot to achieve the corresponding pose adjustment.

[0031] According to a specific embodiment of the present invention, step D, the method for determining the second rotation center includes the following steps:

[0032] d1. The connector transitions from the initial constant force contact state to the slot state.

[0033] d2. Calculate the distances from both ends of the male connector to the female connector;

[0034] d3. Calculate the position of the second center of rotation;

[0035] d4. Calculate the position of the male connector after rotating a specific angle around the second rotation center, and guide the robot to achieve the corresponding pose adjustment.

[0036] According to a specific embodiment of the present invention, in step E, the rotational speed and translational speed of the male connector are adjusted in real time using the following formula:

[0037]

[0038] Where k v k is the deceleration ratio for rotational motion. p For the position closed-loop ratio, w(p) x The value represents the position closed loop of the rotational motion and the weighting coefficient based on the horizontal speed smoothness. Internally, a ReLU function is used to judge the horizontal speed. If the absolute value of the speed is within the set range, a weight of 0 to 1 is output to adjust the horizontal speed. When the horizontal speed is too large or too small, the corresponding speed smoothness and position closed loop process is fully entered. For the rotational motion from the contact stage to the slotting stage, p represents the horizontal movement speed of the assembly surface in the y-axis direction. For the rotation from the slotting stage to the flushing stage, p represents the smoothness adjustment speed in the z-axis direction.

[0039] The present invention has the following beneficial effects:

[0040] 1. The VRC method proposed in this invention can rotate the male connector around the calculated two rotation centers by a fixed angle after the male and female connectors make contact, so as to achieve a flush posture and complete the pressing.

[0041] 2. Other conventional compliance methods, unable to recognize the complex relationship between contact forces and ideal adjustment directions, result in excessive contact forces or blockages in specific postures, thus failing to complete the assembly task. The AVC method proposed in this invention can provide correction for male and female connector contact when network prediction errors are large, and achieves smaller peak contact forces during the assembly process by balancing the magnitudes of speeds. Finally, this method can maintain the stability of the forces in each assembly process during repeated assembly, and it can also be successfully assembled on other sizes and models of RF connectors, demonstrating a certain degree of generalization.

[0042] To more clearly illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0043] Figure 1 This is the assembly flowchart of the RF connector in Example 1;

[0044] Figure 2 This is a schematic diagram of the RF connector assembly in Example 1;

[0045] Figure 3A This is a schematic diagram of the initial contact state in Example 1;

[0046] Figure 3B This is a simplified geometric diagram of the initial contact state in Example 1;

[0047] Figure 4A This is a schematic diagram of the male connector rotating around the first rotation center in Embodiment 1;

[0048] Figure 4B yes Figure 4A A simplified geometric sectional view;

[0049] Figure 4C yes Figure 4A A simplified diagram of a squint;

[0050] Figure 4D This is a simplified contact diagram of the card slot area;

[0051] Figure 5A This is a schematic diagram of the contact point changes from the slot stage to the flush stage in Example 1.

[0052] Figure 5B yes Figure 5A A simplified sectional view;

[0053] Figure 5C yes Figure 5A A simplified diagram of a squint;

[0054] Figure 6A This is a schematic diagram of the male connector rotating around the second rotation center in Embodiment 1;

[0055] Figure 6B yes Figure 6A A simplified sectional view;

[0056] Figure 6C yes Figure 6A A simplified diagram of a squint;

[0057] Figure 7A This is a schematic diagram of the angle error before attitude adjustment in Example 1;

[0058] Figure 7B This is a schematic diagram of the angle error after attitude adjustment in Example 1;

[0059] Figure 8A This refers to the positive position error during the attitude adjustment process in Example 1.

[0060] Figure 8B This refers to the negative position error during the attitude adjustment process in Example 1.

[0061] Figure 9AThis is a diagram showing the change in force during the first adjustment process in Example 1;

[0062] Figure 9B This is a diagram showing the change in torque during the first adjustment process in Example 1;

[0063] Figure 9C This is a diagram showing the change in force during the second adjustment process in Example 1;

[0064] Figure 9D This is a graph showing the change in torque during the second adjustment process in Example 1;

[0065] Figure 9E This is a diagram showing the change in force during the third adjustment process in Example 1;

[0066] Figure 9F This is a graph showing the change in torque during the third adjustment process in Example 1;

[0067] Figure 9G This is a diagram showing the change in force during the fourth adjustment process in Example 1;

[0068] Figure 9H This is a diagram showing the change in torque during the fourth adjustment process in Example 1;

[0069] Figure 10A This is a graph showing the speed changes during the third adjustment process in Example 1;

[0070] Figure 10B This is a graph showing the speed change during the fourth adjustment process in Example 1. Detailed Implementation

[0071] Many specific details are set forth in the following description in conjunction with embodiments in order to provide a full understanding of the invention. However, it should be understood that the following embodiments and detailed descriptions are for illustrative purposes only and do not limit the scope of protection of the invention.

[0072] Example 1

[0073] This embodiment provides an automated assembly method for radio frequency (RF) connectors, used for automatically assembling male and female connectors of RF connectors. The assembly end of the female connector is cylindrical, and the assembly end of the male connector is correspondingly provided with a circular groove. After assembly, the cylinder is embedded in the circular groove. The automated assembly method includes the following steps:

[0074] A. The female connector remains stationary, while the male connector moves horizontally above the female connector and comes into contact with it.

[0075] B. Collect force sensor data to obtain contact force information between the male and female connectors, and filter and compensate for tool gravity on the data;

[0076] C. Input the processed force data into the KAN network to obtain the predicted positional error between the male and female connectors;

[0077] D. Based on the position error, the first and second rotation centers of the two rotations are calculated using the virtual rotation center algorithm, thereby obtaining the pose change of the male connector after the two rotations and calculating the speed of the male connector in the two rotations.

[0078] E. The processed force data is simultaneously input into the admittance controller to obtain the compliance velocity;

[0079] F. Input the compliant speed and the two rotational speeds into the speed controller to solve for the speed and displacement of each joint required by the robot to achieve the corresponding movement of the male connector, and complete the pose adjustment.

[0080] G. (Press and assemble) Press the male connector to complete the assembly.

[0081] In step D, the two rotations are as follows:

[0082] The first stage of rotation (slot rotation) involves the male connector rotating around the first rotation center in the vertical plane, causing the cylindrical end of the female connector to engage with the groove at the assembly end of the male connector, achieving a slotted state. At this point, the male connector is tilted.

[0083] The second stage of rotation (alignment rotation) involves the male connector rotating around the second rotation center in a vertical plane until the male connector is aligned with the female connector.

[0084] In step D, the method for determining the first center of rotation includes the following steps:

[0085] D1. The connector transitions from a non-contact state to a constant force contact state;

[0086] D2. The KAN network makes a preliminary prediction of the positional error (distance error) between the male and female connectors;

[0087] D3. Calculate the distances from both ends of the male connector to the female connector based on the positional error;

[0088] D4. Calculate the position of the first center of rotation;

[0089] D5. Calculate the position of the male connector after rotating a specific angle around the first rotation center, and guide the robot to achieve the corresponding pose adjustment.

[0090] In step D, the method for determining the second center of rotation includes the following steps:

[0091] d1. The connector transitions from the initial constant force contact state to the slot state.

[0092] d2. Calculate the distances from both ends of the male connector to the female connector;

[0093] d3. Calculate the position of the second center of rotation;

[0094] d4. Calculate the position of the male connector after rotating a specific angle around the second rotation center, and guide the robot to achieve the corresponding pose adjustment.

[0095] In step E, the rotational and translational speeds of the male connector are adjusted in real time using the following formula:

[0096]

[0097] Where k v k is the deceleration ratio for rotational motion. p For the position closed-loop ratio, w(p) x The value represents the position closed loop of the rotational motion and the weighting coefficient based on the horizontal speed smoothness. Internally, a ReLU function is used to judge the horizontal speed. If the absolute value of the speed is within the set range, a weight of 0 to 1 is output to adjust the horizontal speed. When the horizontal speed is too large or too small, the corresponding speed smoothness and position closed loop process is fully entered. For the rotational motion from the contact stage to the slotting stage, p represents the horizontal movement speed of the assembly surface in the y-axis direction. For the rotation from the slotting stage to the flushing stage, p represents the smoothness adjustment speed in the z-axis direction.

[0098] Based on experience in manually assembling RF connectors, when the male RF connector is manually clamped and kept parallel to the z-axis of {OP} and {ORt} while approaching the female connector to make contact, the operator can use small-range pose adjustments to sense the force changes under multi-point contact conditions of the male and female connectors during movement. Two contact states are defined during the process:

[0099] (1) Initial contact state. This refers to the state when the male and female connectors transition from non-contact to just-contact. Since both assembly lines and manual assembly involve keeping the z-axis of {OP} and {ORt} parallel and completing the assembly with a single press after precise positioning, we ignore the possible posture error in the initial contact state and only consider the position error.

[0100] (2) Alignment state. That is, the origin and z-axis of the male and female joint coordinate system {OP} and {ORt} coincide.

[0101] As the positional error between {OP} and {ORt} gradually decreases and approaches a state of near-alignment, the guiding effect of the chamfer becomes clearly perceptible. At this point, the force required to move towards the aligned orientation decreases, while the reverse movement is significantly affected by resistance. This state is defined here as:

[0102] (3) Slotted state. In this contact state, part of the outer ring of the female connector is located in the slot between the inner and outer rings of the male connector. At this time, the horizontal movement applied to the male connector will be hindered by the reverse support force FN due to the contact of the outer rings of the male and female connectors on the opposite side. This reduces the search area of ​​the male connector in the search phase to a certain extent and assists in the center positioning of the male and female connectors.

[0103] The initial contact state and the leveling state serve as the beginning and end of the search phase, respectively, while the slot state serves as an intermediate state. The search phase can be divided into two steps: from the initial contact state to the slot state; and from the slot state to the leveling state. The overall process of the search phase is as follows: Figure 2 As shown, the specific analysis is as follows:

[0104] (1) First, analyze the position parameters under the initial contact state. When the male connector moves downward along the z-axis of {ORt} from the uncontacted state and is subjected to the expected z-axis force, the male and female connectors enter the initial contact state. At this time, there may be a positional error at the center of the male and female connectors, as shown in the schematic diagram. Figures 3A-3B As shown in the figure. For simplified analysis, the complex outer metal ring of the male and female connectors is considered a regular ring of uniform thickness. Since the deformation of the male connector's outer ring is small during the adjustment phase, it is negligible. The green dots in the figure represent the contact points of the male and female connectors. The distance error pxy (represented by the black dashed line) between the centers of the male and female connectors can be seen at this point. This distance error has an angular error ρ relative to the x-axis of the {ORt} coordinate system. Since physical modeling cannot obtain this error value, a KAN network will be used for preliminary prediction. The construction and use of the KAN network will be described in detail later.

[0105] Directly using the predicted horizontal error for horizontal pose adjustment presents several problems: First, the predicted value itself contains errors, including numerical and directional errors introduced by force sensor signal noise, errors introduced by simplifying the connector model, and prediction errors. Second, maintaining contact in the vertical direction while moving horizontally could potentially damage internal connector components. Third, finding a suitable contact state for determining the current position during horizontal movement is also difficult. Therefore, this method involves rotating the male connector around a specific center point to reduce horizontal obstruction and collision issues between the male and female connectors, allowing them to enter a slotted state and thus completing the initial positioning.

[0106] Step 1: First stage of virtual center rotation. After rotating the male connector by a specified angle θ along the torque direction, the inner ring of the male connector may abut against one end of the outer ring of the female connector. To allow the male and female connectors to enter the slotted state, the male connector should then be displaced horizontally, such as... Figures 4A-4D As shown, the gray area in the middle represents the initial pose of the male connector at the beginning of rotation, and the light red area represents the ideal pose after rotation through the virtual rotation center. Figure 4CSimplified oblique view diagram calculated with the rotation center. Figure 4D This diagram illustrates the embedding depth of the female connector in the slotted area. As can be seen, by connecting the two ends of the male connector's outer ring before and after movement and drawing the perpendicular bisector, the ideal center of rotation can be obtained. Rotating around this center eliminates the need for horizontal movement, allowing direct rotation to the slotted state. The obstruction between the male connector's inner ring and the female connector's outer ring can be reduced by constant force contact along the z-axis. When the rotation angle is fixed at θ and the male and female connectors are in the slot, the male connector's sinking depth h can be obtained through geometric relationships.

[0107]

[0108] Where d1 is the minimum width of the inner and outer grooves of the male connector, and d2 is the maximum thickness of the outer ring of the female connector. By determining the recess depth and rotation angle of the male connector, the line connecting the starting points of the rotation of the outer ends on both sides of the male connector can be fixed.

[0109] Here, the length of the perpendicular bisector of the male connector at one end of the slot is defined as b, and at the other end as a. The subscripts h and v of the perpendicular bisector length represent the horizontal and vertical components of the connecting line, respectively. Based on geometric relationships, the dimensions can be calculated as follows:

[0110]

[0111] After obtaining the lengths of each chord, according to geometric relationships, the central angles corresponding to the lengths of chords a and b are the same. The midpoints of chords a and b are A and B respectively, and their left-hand points are A', A'', and B' ... ’ B ’ A ’ B ’ The length is 2R, ∠A ’ CB ’ It equals α + β, which can be obtained based on the relationship between similar triangles.

[0112]

[0113] In ΔA ’ CB ’ Substituting into the cosine formula, we get

[0114]

[0115] Finally, the radius of rotation at end B can be calculated as follows:

[0116]

[0117] Given the direction of the radius and its direction relative to the chord length, the virtual center of rotation C can be determined.

[0118] Step 2: Second stage virtual center rotation. After the male and female connectors reach the slot, the contact state between the male and female connectors is as follows: Figures 5A-5CAs shown. To move the male connector towards a flush position, considering the contact between the male and female connectors in the flush position—the outer ring of the female connector mainly contacts the inner side of the outer ring of the male connector—after step 1, the outer ring of the female connector should make contact from the side of the male connector's outer ring. This lateral contact point is defined as Ds. Simultaneously, there will be multiple contact points on the top of the male and female connector's outer rings; these contact points are defined as Dt. The position changes of each contact point as the male connector's pose is adjusted as follows: Ds and Dt both use the contact surface of the female connector as a path, shifting along the male connector's rotation direction. Towards the end of the adjustment, Ds and Dt will gradually approach the two endpoints of the female connector. Finally, when Ds and Dt reach the two endpoints, the contact area of ​​the male and female connectors will transition from point contact to surface contact.

[0119] The process of moving from the slotted state to the flush state can also be viewed as the male connector rotating around a remote center, such as... Figures 5A-5C As shown. At this time, end B moves vertically upwards along the outer ring of the female connector, with an angle β of 90°. Therefore, the center of rotation C is located on the perpendicular bisector of end B. Based on set relations, the angle α between end A and the horizontal direction can be calculated, and the chord lengths a and b of ends A and B are...

[0120]

[0121] Similarly, from Figures 6A-6C As shown in the triangle relationship, the central angles corresponding to the chord lengths of segments A and B are equal. Similarly, the radius |BC| corresponding to the chord length at end B can be obtained from equations (0-4), (0-5) and (0-6).

[0122] (2) Admittance velocity control

[0123] Since the center distance and angle of the male and female connectors are unknown at initial contact, prediction using a KAN network (neural network) will introduce errors: errors in distance will cause the calculated virtual rotation center position to deviate from the expected value, preventing the male connector from reaching the expected slot state after rotating around the point; while errors in angle will prevent the rotation plane from coinciding with the assembly plane, causing unexpected contact and collisions during the rotation process. To solve these problems, this invention proposes a force compliance strategy to adapt to assembly errors.

[0124] In complex contact environments, compliance control can effectively prevent the generation of extreme contact forces. For example... Figures 7A-7B As shown, during the shaft hole search stage, by following the coordinate system {O} of the female connector... Rt The constant force along the z-axis ensures compliance, maintaining the male and female connectors while preventing damage from excessive contact force. Apart from the z-axis direction, when angular errors exist, the male connector's rotation plane and the assembly plane form an angle dρ, such as... Figures 7A-7B As shown, when the male connector rotates at this time, at {O AThe outer ring of the coordinate system in the positive y-axis direction will have more contact with the female connector, resulting in greater strain on the outer ring. The force acting on the male connector will eventually point in the positive y-axis direction. At this time, compliance along the direction of force F will change the contact point between the male and female connectors, and finally the rotating plane is called the new assembly plane, which symmetrically bisects the male and female connectors.

[0125] Along the x-axis, due to errors in distance prediction, there is an error between the virtual rotation center and the desired position, such as... Figures 8A-8B As shown, C and C * The symbols represent the ideal rotation center and the rotation center with error. Light red and dark red represent the ideal male connector pose around the ideal rotation center and the male connector pose around the error rotation center, respectively. Combining equations (0-2) and (0-3) for analysis: For case (a), the positive error leads to p xy The value increases, and thus b increases. h and decrease a h This causes the calculated position of the male connector to shift to the right relative to the current position, and the calculated rotation center also shifts to the right. This results in a decrease in the center displacement relative to its own rotation angle when the male connector rotates around the error rotation center at the current position. This can easily lead to contact between the outer ring of the internal functional components or the middle area of ​​the male connector and the female connector. In this case, the ideal compliance direction of the male connector is along the negative x-axis of the {A} coordinate system. Adjusting along this direction will subject the male connector to a reverse force F. x Function. In case (b), the negative error will cause the calculated rotation center to shift to the left, which will increase the displacement of the male connector center relative to the rotation angle when the male connector rotates around the rotation center. In terms of relative pose, the male connector rotates around the rotation center by the same angle, but its own tilt angle increases. This will also easily lead to the contact state in case (a).

[0126] To address both scenarios, the male connector's groove structure allows it to move in an ideal, compliant direction. When the female connector's outer ring is embedded in the groove, further movement in that direction causes the male connector's outer ring to press against the female connector's outer ring, creating a greater contact force. Therefore, a suitable positive x-direction force F can be set. d This allows the male and female connectors to reach the slotted state. Furthermore, with the application of this compliance algorithm, the male connector does not need to rotate through its entire stroke; rotating only a fixed angle is sufficient to achieve the slotted state, facilitating the generalization and application of the algorithm. The compliance control formulas in the x, y, and z directions can be written as follows:

[0127]

[0128] Where p = [p x ,p y ,p z ] T M, B, and K are the admittance control parameters, and the desired force F is...d =[F dx ,0,F dz ] T .

[0129] Simultaneously with the horizontal movement, rotation around the remote center also occurs. The distance of this rotational movement is given and known. If the error generated during rotation is not smoothly adjusted in time by the horizontal movement, further rotation may lead to excessive contact force between the male and female connectors. Therefore, the speed of the rotational movement should be constrained by the horizontal speed. Based on the above analysis, this paper proposes a position closed-loop control algorithm for the rotational speed to adjust the rotational and translational speeds of the male connector in real time. The formula is expressed as follows:

[0130]

[0131] Where k v k is the deceleration ratio for rotational motion. p For the position closed-loop ratio, w(p) x This indicates the rotational motion's position closed-loop adjustment and the weighting coefficients based on horizontal velocity smoothing. Internally, a ReLU function judges the horizontal velocity. If the absolute value of the velocity is within the set range, a weight of 0 to 1 is output to adjust the horizontal velocity. When the horizontal velocity is too large or too small, the corresponding velocity smoothing and position closed-loop process is fully entered. For the rotational motion from the contact stage to the slotting stage, This represents the horizontal movement speed of the assembly surface along the y-axis. However, for the rotation from the slotting stage to the flushing stage, This indicates the smooth adjustment speed in the z-axis direction.

[0132] To verify the effectiveness of the method proposed in this embodiment, four experimental groups were designed. The first group used a conventional admittance control algorithm as a two-stage rotational controller (ADC) to achieve rotational compliance of the force; the second group used the origin O of the end-effector coordinate system. T Rotation adjustment is performed using the center of rotation (O) T +ADC); the third and fourth groups use the proposed virtual rotation center to guide rotation (VRC, VRC+AVC). The first three groups use admittance control to balance the contact force in the horizontal direction, while the fourth group uses the proposed speed controller to adjust the motion speed in each direction. In addition, for experimental groups two, three, and four, the rotation angle is set to 5°, and the experimental object used in all four groups is the MHF-I model RF connector.

[0133] Comparison of forces and torques during the adjustment process under the same assembly conditions. For example... Figures 9A-9BAs shown, the conventional admittance control method causes the male and female connectors to begin to disengage after initial contact adjustment and horizontal compliance, eventually leading to an accidental collision. During this process, the maximum lateral contact force reaches 9.294 N, and the torque reaches 0.641 Nm. Figures 9C-9D In the middle, using the coordinate system center O around the end tool T The method of achieving posture compliance, however, encounters a bottleneck. This method causes the male connector to oscillate back and forth within a certain angle, which is why the force involved in this process is relatively small. Although this method can guide the correct compliance direction by oscillating within a certain range when the r value is small, thus bringing the chamfered areas of the male and female connectors into contact, its applicability is low when facing larger errors. As can be seen from the adjustment process of the first two methods, due to the complex contact forces of RF connectors, compliance based solely on contact forces is prone to getting stuck in local optima or losing contact, failing to converge to the correct position. This is because, in some poses, the ideal adjustment direction of the male connector is opposite to the direction of force growth, therefore, relying solely on compliance is insufficient to achieve correct assembly. Figures 9E-9F The virtual rotation center assembly strategy used in this study adjusts the attitude by rotating around the calculated virtual rotation center in two stages. This method actively adjusts according to the designed trajectory, thereby effectively getting rid of the problem of local blockage and effectively avoiding the occurrence of excessive contact force due to accidental collisions, reducing the overall contact force value, and reducing the force and torque values ​​to -7.728N and 0.105Nm, respectively.

[0134] To verify the effectiveness of the AVC algorithm, this paper adds the AVC algorithm to the third VRC experiment. Here, η is set to 1, and p in the y-axis and z-axis directions... l With p h The speeds are 0.1 mm / s and 0.4 mm / s respectively, with compliance parameters A, B, and C being 1, 40, and 200 respectively. It can be seen that under experimental conditions with small angle prediction errors, the assembly success rates are similar, while under conditions with large angle prediction errors, the use of a speed controller can effectively improve the success rate. The reason for this can be seen from the movement speeds of both components. Figure 10A As shown, because the rotational speed and horizontal speed are independent of each other, the horizontal error cannot be adjusted in time when the male connector is being adjusted, resulting in an error between the rotating plane and the ideal mating surface, thus leading to greater unexpected contact force and adjustment error. Figure 10B When the speed in the y-axis direction exceeds 0.1 mm / s, the rotational speed will decrease accordingly, allowing horizontal adjustment to take priority and ensuring correct positioning in the horizontal direction. Although this sacrifices efficiency, it effectively improves the success rate. Furthermore, the mutual constraint of speeds also reduces the contact force between connectors. Figures 9G-9H As can be seen, the peak force and torque during the adjustment process were -5.105N and 0.091Nm, respectively, a decrease of 33.9% and 13.3% year-on-year.

[0135] Although the present invention has been described above by way of embodiments, the above embodiments are only used to exemplify possible implementations of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or changes made by those skilled in the art in accordance with the present invention should also be covered by the scope of protection defined by the claims of the present invention.

Claims

1. An automatic assembly method for radio frequency connectors, used for automatically assembling male and female connectors of radio frequency connectors, wherein the assembly end of the female connector is cylindrical, and the assembly end of the male connector is correspondingly provided with a circular groove, and after assembly, the cylindrical part is embedded in the circular groove; characterized in that, The automatic assembly method includes the following steps: A. The female connector is stationary, and the male connector moves to above the female connector and contacts the female connector; B. Collect force sensor data to obtain contact force information between the male connector and the female connector, and filter and compensate for tool gravity on the data; C. Input the processed force data into the KAN network to obtain the predicted positional error between the male connector and the female connector; D. Based on the position error, the first and second rotation centers of the two rotations are calculated using the virtual rotation center algorithm, thereby obtaining the pose change of the male connector after the two rotations and calculating the speed of the male connector in the two rotations. E. The processed force data is simultaneously input into the admittance controller to obtain the compliance velocity; F. Input the compliant speed and the two rotational speeds into the speed controller to solve for the speed and displacement of each joint required by the robot to achieve the corresponding movement of the male connector, and complete the pose adjustment. G. Press the male connector to complete the assembly.

2. The automatic assembly method according to claim 1, characterized in that, In step D, the two rotations are as follows: In the first stage of rotation, the male connector rotates around the first rotation center in a vertical plane, causing the cylinder at the assembly end of the female connector to engage in the groove at the assembly end of the male connector, achieving a slotted state. At this time, the male connector is tilted. In the second stage of rotation, the male connector rotates around the second rotation center in a vertical plane until the male connector is flush with the female connector.

3. The automatic assembly method according to claim 1, characterized in that, In step D, the method for determining the first center of rotation includes the following steps: D1. The connector transitions from a non-contact state to a constant force contact state; D2. The KAN network initially predicts the positional error (distance error) between the male connector and the female connector; D3. Calculate the distances from both ends of the male connector to the female connector based on the positional error; D4. Calculate the position of the first center of rotation; D5. Calculate the position of the male connector by rotating it around the first rotation center by a specific angle, and guide the robot to achieve the corresponding pose adjustment.

4. The automatic assembly method according to claim 1, characterized in that, In step D, the method for determining the second center of rotation includes the following steps: d1. The connector transitions from the initial constant force contact state to the slot state. d2. Calculate the distances from both ends of the male connector to the female connector; d3. Calculate the position of the second center of rotation; d4. Calculate the position of the male connector by rotating it around the second rotation center by a specific angle, and guide the robot to achieve the corresponding pose adjustment.

5. The automatic assembly method according to claim 1, characterized in that, In step E, the rotational and translational speeds of the male connector are adjusted in real time using the following formula: Where k v k is the deceleration ratio for rotational motion. p For the position closed-loop ratio, w(p) x This indicates the rotational motion's position closed-loop operation and the weighting coefficients based on horizontal velocity smoothness. Internally, a ReLU function is used to determine the horizontal velocity. If the absolute value of the velocity is within the set range, a weighted value of 0 to 1 is output to adjust the horizontal velocity. When the horizontal velocity is too high or too low, the corresponding velocity smoothness and position closed-loop process is fully entered. For the rotational motion from the contact stage to the slotting stage, This represents the horizontal movement speed of the assembly surface along the y-axis. However, for the rotation from the slotting stage to the flushing stage, This indicates the smooth adjustment speed in the z-axis direction.

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