A transfer device for an automatic production line of brake discs

Abstract

The present application relates to the technical field of manufacturing transportation, and particularly relates to a transfer device for a brake disc automatic production line, which comprises a transfer device, a gantry truss support system, a horizontal moving slide table, a vertical lifting mechanism and an end grabbing mechanism; a flatness detection unit, which is used to determine a surface state of the brake disc based on a vertical distance from each measured point to a fitted plane to determine a plane fitting residual error to adjust a descending grabbing speed; a clamping control unit, which is used to determine a uniformity coefficient of fitting to determine whether the fitting is uneven in combination with a threshold curve interval; a center hole flaw unit, which is used to determine whether a characteristic parameter meets a characteristic criterion in combination with a corresponding characteristic threshold value to determine a motion working condition of a pawl and adjust a force control mode of the pawl. The present application realizes self-adaptive, lossless and reliable transportation of a rigid structure grabbing process by detecting a reference surface physical state and regulating clamping force feeling fitting and dynamic balance.

Description

Technical Field

[0001] This invention relates to the field of manufacturing transfer technology, and in particular to a transfer device for an automated production line of brake discs. Background Technology

[0002] In automated brake disc production lines, the transfer of workpieces from the initial loading of the cast blank to processes such as precision turning and grinding is a crucial link that determines the production line's cycle time and the quality of the finished product. Brake discs are heavy and disc-shaped, with their center hole and brake surface hub end face serving as the core positioning references for subsequent machining. However, the reference surface condition of the cast blank has inherent uncertainties; the surface may have residual burrs, oxide scale, or local warping, and the placement posture during loading also has random deviations depending on the pallet or conveyor line condition. Traditional gantry robots or articulated robots generally adopt a "visual positioning followed by rigid gripping" model: that is, a camera captures the workpiece position, and the robot performs gripping according to a fixed trajectory and fixed clamping force. This method is efficient when the workpiece reference surface is flat and the posture is regular, but when facing blanks with surface defects or posture deviations, the hard contact between the rigid gripper and the irregular reference surface can easily lead to concentrated clamping force, skewed positioning references, or workpiece surface damage. This can affect the accuracy of subsequent machining or even cause the workpiece to fall off or collide. Furthermore, existing solutions rely heavily on fixed thresholds to determine gripping conditions, lacking the ability to hierarchically identify the true physical state of the workpiece's reference surface, thus failing to achieve a dynamic balance between efficiency and safety. Therefore, there is an urgent need for a transfer device capable of actively sensing the physical state of the workpiece's reference surface and adaptively adjusting the gripping strategy based on the sensing results. This would address the challenge of non-destructive and reliable gripping of rigid structures with uncertain workpieces while maintaining high cycle times.

[0003] Chinese Patent Publication No. CN114701559A discloses a brake disc logistics transfer device. Through the arrangement of a snap-fit ​​mechanism, a limiting sleeve, a first hydraulic pump, a first telescopic bracket, and a limiting clamp, the air outlet pipe drives the first telescopic bracket to quickly extend and retract. A limiting clamp is provided on one side of the first telescopic bracket, causing the first telescopic bracket to drive the limiting clamp to quickly compress the interior of the brake disc. Therefore, the brake disc logistics transfer device has the following problems: When faced with uncertainties such as positional deviations, local concavities and burrs in the reference surface of the cast blank brake disc, the existing rigid truss transfer device cannot adjust the gripping strategy, resulting in damage to the positioning reference, imbalance of clamping force, or gripping failure. Summary of the Invention

[0004] Therefore, the present invention provides a transfer device for an automated production line of brake discs, which overcomes the problem in the prior art that the transfer device cannot adjust the gripping strategy when facing uncertainties such as the positional deviation, local concavity and convexity, and burrs in the hole of the reference surface of the cast brake disc blank, resulting in damage to the positioning reference, imbalance of clamping force, or gripping failure.

[0005] To achieve the above objectives, the present invention provides a transfer device for an automated brake disc production line, comprising: The transfer device includes a gantry truss support system, a horizontal moving slide, a vertical lifting mechanism, and an end gripping mechanism; The flatness detection unit is used to measure the unit normal vector of the brake disc hub surface by contacting several actual measurement points, determine the plane fitting residual based on the vertical distance from each actual measurement point to the fitting plane to determine the surface state of the brake disc, and adjust the descent and gripping speed of the end gripping mechanism. The clamping control unit is used to determine the initial contact point based on the actual pressure of several grippers of the end gripping mechanism, determine the adhesion unevenness coefficient based on several gripper actual pressures, combine several threshold curve ranges to determine whether the adhesion is uneven, and adjust the gripper posture. The center hole defect unit is used to determine the feature parameters based on the feature parameters of each jaw of the gripper, and to determine the motion condition of the jaw by combining the corresponding feature threshold with the feature criteria, and to adjust the force control mode of the jaw. The threshold negative feedback adjustment unit is used to determine the stability margin index of the current batch based on the final clamping force balance dispersion and the final bonding non-uniformity coefficient after several workpieces are gripped, so as to adjust the threshold of the plane fitting residual.

[0006] Furthermore, the flatness detection unit includes, The plane fitting residual determination sub-unit is used to determine the vertical distance based on the spatial coordinates of the measured point and the unit normal vector of the hub surface, and to determine the plane fitting residual based on the root mean square value of several vertical distances. The residual comparison subunit is used to determine the surface condition of the brake disc based on the comparison results between the plane fitting residual and the ideal plane threshold and the graspable limit threshold. The residual adjustment subunit, in response to the surface condition of the brake disc, determines the deceleration magnitude based on the ratio of the ideal plane threshold to the plane fitting residual, and reduces the descent gripping speed of the end gripping mechanism based on the deceleration magnitude.

[0007] Furthermore, the residual comparison sub-unit compares the plane fitting residual with the ideal plane threshold and the graspable limit threshold; Based on the plane fitting residual being less than or equal to the ideal plane threshold, the residual comparison sub-unit determines that the brake disc is in the first surface state, determines the plane center point as the gripping height reference, and determines the gripping posture reference based on the unit normal vector. Based on the plane fitting residual being greater than the ideal plane threshold and less than or equal to the graspable limit threshold, the residual comparison subunit determines that the brake disc is in the second surface state. The brake disc surface is uneven, and the residual adjustment subunit reduces the descent grasping speed of the end gripping mechanism. Based on the plane fitting residual being greater than the graspable limit threshold, the residual comparison subunit determines that the brake disc is in the third surface state, the residual adjustment subunit stops the grasping cycle, and the end grasping mechanism is raised to the initial height.

[0008] Furthermore, the clamping control unit includes, The uniformity coefficient determination sub-unit is used to determine the instantaneous resultant force based on the sum of the actual pressures of several grippers, and to determine the non-uniformity coefficient of the fit based on the ratio of the difference between the maximum and minimum pressure values ​​to the average actual pressure value. The bonding comparison subunit is used to determine the initial contact point based on the position where the instantaneous resultant force is greater than the reference value, and to determine whether the bonding is uneven based on the comparison result of the bonding unevenness coefficient and the unevenness coefficient threshold curve. The fit adjustment subunit is used to determine the low point direction in response to uneven fit, and adjust the gripper posture based on the low point direction.

[0009] Furthermore, the clamping control unit determines the non-uniformity coefficient of the fit during each servo cycle from the initial contact point to the instantaneous combined force reaching the target preload. The non-uniformity coefficient threshold curve includes an initial loose region, a mid-term convergent region, and a final strict region. The corresponding non-uniformity coefficient threshold is determined based on each interval of the matching comparison sub-unit. The initial relaxation zone is the threshold curve range where the instantaneous resultant force is lower than the resultant force threshold range, and the non-uniformity coefficient threshold is set to the maximum value of the range. The intermediate convergence region is the threshold curve interval where the instantaneous resultant force is within the resultant force threshold range, and the non-uniformity coefficient threshold decreases linearly with the increase of the instantaneous resultant force. The final strict region is the threshold curve interval where the instantaneous resultant force exceeds the resultant force threshold range, and the non-uniformity coefficient threshold is set to the minimum value of the interval.

[0010] Furthermore, the non-uniformity coefficient of the bonding comparison sub-unit is compared with the corresponding non-uniformity coefficient threshold of each interval; Before the instantaneous combined force reaches the target preload, if the non-uniformity coefficient of the bonding is less than the corresponding non-uniformity coefficient threshold of each interval, the bonding comparison sub-unit determines that the positioning ring surface has successfully achieved adaptive bonding. Before the instantaneous combined force reaches the target preload, if the non-uniformity coefficient of the bonding is greater than the non-uniformity coefficient threshold corresponding to any current interval, the bonding comparison sub-unit determines the non-uniformity of the bonding.

[0011] Furthermore, the central hole defect unit includes, The feature parameter determination subunit is used to determine feature parameters based on the feature parameters of each jaw. The jaw feature parameters include real-time current, real-time rotation speed, and real-time position. The feature parameters include current surge factor, force-displacement stiffness coefficient, and instantaneous power characteristic ratio. The criterion comparison subunit is used to determine whether the claw has touched a burr or a foreign object based on the feature parameter and the corresponding feature threshold conforming to the feature criterion. The clamping adjustment subunit is used to switch the clamp to torque-limited mode for low-speed advancement based on the determination that the clamp has touched a burr or foreign object. It restores the normal force control mode when the current surge factor drops below the factor threshold after the advancement displacement exceeds the displacement distance. It stops the clamp advancement and reverses slightly when the clamp meets the obstruction confirmation criterion and the real-time current meets the current surge criterion after the advancement displacement exceeds the displacement distance.

[0012] Furthermore, the criterion comparison sub-unit determines that the real-time current of the chuck meets the current surge criterion based on the current surge factor being greater than the factor threshold; the criterion comparison sub-unit determines that the chuck meets the high stiffness criterion based on the force displacement stiffness coefficient being greater than the coefficient threshold; and the criterion comparison sub-unit determines that the chuck meets the obstruction confirmation criterion based on the instantaneous power characteristic ratio being less than the characteristic ratio threshold.

[0013] Furthermore, the current surge factor is determined based on the ratio of the real-time current change value to the rated current within the sliding time window, and is used to determine the severity of the current surge. The force-displacement stiffness coefficient is determined based on the ratio of current increment to displacement increment, and is used to distinguish between the gripping conditions of rigid barrier burrs and normal clamping in elastic deformation zones. The instantaneous power characteristic ratio is determined based on the product of real-time current and real-time rotation speed, and is used to eliminate current spikes during non-contact current fluctuations.

[0014] Furthermore, the threshold negative feedback adjustment unit includes, The stability margin determination sub-unit is used to determine the stability margin index based on the average maximum value of the final bonding non-uniformity coefficient and the final clamping force balance dispersion within the highest range of several workpieces in the current batch. The margin comparison sub-unit is used to compare the stability margin index with the ideal margin band. If the stability margin index is lower than the ideal margin band, the transfer capacity margin is determined to be sufficient. If the stability margin index is higher than the ideal margin band, the transfer capacity margin is determined to be insufficient. The threshold adjustment subunit is used to increase the ideal plane threshold when the transport capacity margin is sufficient, and to decrease the graspable limit threshold when the transport capacity margin is insufficient.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: the flatness detection unit fits the plane with contact measurement points and calculates the residual, thus eliminating workpiece tilt and local defects and classifying the surface condition to control the gripping speed; the clamping control unit uses a non-uniformity coefficient combined with a slope-shaped dynamic threshold curve to achieve compliant fit and active attitude fine-tuning of the gripper positioning surface on irregular surfaces under force guidance; the center hole defect unit accurately identifies burrs in the hole using a three-dimensional criterion composed of current surge factor, force displacement stiffness coefficient and instantaneous power characteristic ratio, and achieves dynamic balanced clamping with a graded fault-tolerant strategy for creep breakthrough or micro-retreat avoidance; the threshold negative feedback adjustment unit, based on the force distribution quality statistics after batch gripping is completed, drives the autonomous evolution of the judgment threshold with a stability margin index, so that the device can maintain an ideal balance between efficiency and safety during long-term operation.

[0016] Furthermore, this invention solves the problem of non-destructive and reliable gripping of a rigid gantry structure when the state of the datum surface of a cast blank is uncertain by integrating active tactile detection with hierarchical decision-making. It utilizes three contact displacement sensors arranged in an equilateral triangle to actively detect the hub surface, using plane fitting residuals to isolate the overall tilt and local defects of the workpiece, achieving an objective quantification of the true physical flatness of the datum surface, rather than relying on visual estimation or weighted guessing. Based on the hierarchical comparison of the plane fitting residuals with dual thresholds, the workpiece surface state is divided into three levels: excellent, compensable, and ungripable. This drives the gripping strategy to autonomously switch between rigid efficiency and compliant safety, balancing production line cycle time and gripping reliability. When there is local unevenness on the datum surface, the descent speed is dynamically adjusted according to the ratio of the plane fitting residual to the ideal threshold, allowing the equipment capacity to adaptively match the workpiece state, avoiding rigid collisions and damage to the positioning datum, thus ensuring the accuracy of subsequent machining from the source.

[0017] Furthermore, this invention achieves adaptive bonding of the rigid gripper to irregular workpiece surfaces through the coordinated use of a bonding non-uniformity coefficient and a slope-shaped dynamic threshold curve. The bonding non-uniformity coefficient quantifies the uniformity of force distribution using a relative ratio, ensuring that the same judgment standard is applied throughout the entire process, from a Newton-level light touch to a tens of Newtons of locking, eliminating the need to separately calibrate the force difference threshold for different workpiece specifications. The slope-shaped threshold curve conforms to the physical laws of the bonding process. In the initial loose zone, it safely passes through the unstable force signal stage of the initial contact with high tolerance. In the middle stage, it tightens linearly with the increase of the resultant force to guide the positioning surface to gradually straighten. In the final stage, it tightens when approaching the locking force to ensure high uniformity of the final bonding, thereby avoiding early misjudgment while ensuring the final bonding quality. When bonding non-uniformity is detected, it performs active attitude fine-tuning step by step with the direction of minimum force as the guide, so that the gripper positioning surface achieves balanced contact according to the actual concavity and convexity of the workpiece, avoiding local overload or damage to the positioning reference caused by rigid flattening.

[0018] Furthermore, the difference between this invention and existing technologies in achieving the target clamping force lies in the fact that when the chuck reaches the target current normally, there may be a real-time decrease in rotational speed and an increase in current. However, the current surge factor is usually small at this time, and the force displacement stiffness coefficient will not spike abnormally because the motor enters torque mode to maintain pressure normally in the final stage. Therefore, the three-dimensional criteria can effectively distinguish between the two. Through the combination of multi-dimensional feature parameter joint criteria and graded fault-tolerant strategy, accurate identification and adaptive handling of hard foreign objects such as burrs and iron beads in the center hole are achieved. The three-dimensional criteria are cross-validated from three dimensions: current mutation rate, abnormal resistance stiffness, and substantial motion stagnation. The burr collision event is strictly distinguished from the torque pressure maintenance in the final stage of normal clamping, eliminating the defect of easy false alarms in single current threshold judgment. After confirming the burr, the chuck first attempts to push down the loose obstacle that can be broken through by low-speed creep in torque-limited mode. After breaking through, normal clamping is automatically restored. For hard foreign objects that cannot be broken through, the chuck actively retreats slightly to avoid them and dynamically increases the target current of the remaining chucks to compensate for the loss of clamping force, ensuring that the total clamping force is still balanced and reliable. The graded fault tolerance mechanism ensures that when the gripping system encounters defects in the hole wall, it will neither frequently refuse to grip due to excessive conservatism nor damage the workpiece or gripper due to forceful force. This maximizes the success rate of gripping on the first attempt while ensuring gripping safety.

[0019] Furthermore, this invention achieves self-optimization of the judgment threshold through statistical feedback of the force distribution quality after grasping, thus conforming to the actual incoming material condition; it constructs a stability margin index based on the final non-uniformity coefficient of the fit and the uniform dispersion of the clamping force, quantifying the ease margin of the grasping capacity relative to the severity of the current incoming material; it has sufficient capacity redundancy, relaxes the ideal plane threshold to improve cycle time; it approaches the limit of the grasping capacity, tightens the graspable limit threshold to ensure safety; it does not rely on the statistics of the previous logical branch attribution, but starts from the final physical contact quality, driving the threshold to evolve gently towards the ideal balance point of efficiency and safety, so that the transfer device can maintain a working state that is both efficient and easy during long-term operation. Attached Figure Description

[0020] Figure 1 This is a unit connection diagram of a transfer device for an automated brake disc production line in an embodiment of the present invention; Figure 2 This is a schematic diagram of the transfer device in an embodiment of the present invention; Figure 3 This is a schematic diagram of the front view structure of the brake disc in an embodiment of the present invention; Figure 4 This is a side view of the brake disc structure in an embodiment of the present invention; In the diagram: 1-Column, 2-Beam, 3-Horizontal sliding table, 4-Vertical lifting mechanism, 5-End gripping mechanism, 6-Brake disc, 7-Center hole. Detailed Implementation

[0021] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0024] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Please see Figures 1-4 As shown, Figure 1 This is a unit connection diagram of a transfer device for an automated brake disc production line in an embodiment of the present invention; Figure 2 This is a schematic diagram of the transfer device in an embodiment of the present invention; Figure 3 This is a schematic diagram of the front view structure of the brake disc in an embodiment of the present invention; Figure 4 This is a side view of the brake disc structure in an embodiment of the present invention.

[0026] This invention provides a transfer device for an automated brake disc production line, comprising: The transfer device includes a gantry truss support system, a horizontal moving slide 3, a vertical lifting mechanism 4, and an end gripping mechanism 5; The flatness detection unit is used to measure the unit normal vector of the brake disc hub surface through contact at several actual measurement points. Based on the vertical distance from each actual measurement point to the fitting plane, the plane fitting residual is determined to determine the surface state of the brake disc and the descent and gripping speed of the end gripping mechanism is adjusted. The clamping control unit is used to determine the initial contact point based on the actual pressure of several grippers of the end gripping mechanism, determine the adhesion unevenness coefficient based on several gripper actual pressures, combine several threshold curve ranges to determine whether the adhesion is uneven, and adjust the gripper posture. The center hole defect unit is used to determine the feature parameters based on the feature parameters of each jaw of the gripper, and to determine the motion condition of the jaw by combining the corresponding feature threshold with the feature criteria, and to adjust the force control mode of the jaw. The threshold negative feedback adjustment unit is used to determine the stability margin index of the current batch based on the final clamping force balance dispersion and the final bonding non-uniformity coefficient after several workpieces are gripped, so as to adjust the threshold of the plane fitting residual.

[0027] In this embodiment, the transfer device is a gantry-type robotic arm transfer device.

[0028] The core components include gantry truss support, horizontal moving slide (X-axis module), vertical lifting mechanism (Z-axis module), and end effector gripping mechanism. The gantry truss support consists of two vertical support columns 1 and a horizontally installed crossbeam 2, forming the main frame of the device. The bottom of the columns is fixed to the ground or equipment base through flanges, providing stable support for the entire device. The crossbeam integrates linear motion guide rails, which serve as the horizontal movement carrier for the robot arm.

[0029] The horizontal moving slide is mounted on the guide rail of the crossbeam and can make reciprocating linear motion along the crossbeam. The slide has a built-in drive mechanism such as a servo motor and a synchronous belt / screw to realize horizontal position adjustment, and at the same time support the lifting mechanism and end effector below. The vertical lifting mechanism is fixed below the horizontal moving slide and adopts a linear slide / cylinder structure, which can extend and retract in the vertical direction; it is used to control the lifting action of the end effector and realize the switching of the material picking and unloading height of the brake disc.

[0030] The end gripping mechanism is installed at the end of the vertical lifting mechanism and is designed to fit the circular structure of the brake disc. It can adopt a claw-type or vacuum adsorption structure, and achieves stable gripping by fitting the hub surface or outer edge of the brake disc with the positioning pin / contact surface.

[0031] Specifically, the transfer device is connected in a hierarchical manner, with each component connected sequentially from top to bottom to form a complete motion chain; the horizontal slide moves along the crossbeam to realize the horizontal transfer of the brake disc between different workstations; the lifting mechanism extends and retracts vertically to realize the height action of picking up / releasing materials; the end gripping mechanism completes the gripping and releasing of the brake disc through clamping / adsorption action. The overall process is as follows: the horizontal slide moves to the top of the material handling station, the lifting mechanism descends, the end gripping mechanism grabs the brake disc, the lifting mechanism rises, the horizontal slide moves to the top of the target station, the lifting mechanism descends, and the end gripping mechanism releases the brake disc, completing one transfer cycle.

[0032] Specifically, this invention uses a flatness detection unit to fit a plane to a contact-type measurement point and calculate the residual, thus identifying workpiece tilt and local defects and classifying the surface condition to control the gripping speed. The clamping control unit uses a non-uniformity coefficient combined with a slope-shaped dynamic threshold curve to achieve compliant fit and active attitude fine-tuning of the gripper positioning surface on irregular surfaces under force guidance. The center hole defect unit accurately identifies burrs inside the hole using a three-dimensional criterion composed of current surge factor, force displacement stiffness coefficient, and instantaneous power characteristic ratio, and achieves dynamic balanced clamping with a graded fault-tolerant strategy to achieve creep breakthrough or micro-retreat avoidance. The threshold negative feedback adjustment unit uses a stability margin index to drive the autonomous evolution of the judgment threshold based on the force distribution quality statistics after batch gripping, so that the device can maintain an ideal balance between efficiency and safety during long-term operation.

[0033] In this embodiment, there is a difference in the surface precision of the brake disc after rough machining and fine machining, and the roughness of the bottom disc surface will cause the top disc surface to tilt, and there may be burrs in the hole.

[0034] The flatness detection unit controls three contact displacement sensors arranged in an equilateral triangle, with a range of ±5mm and a resolution of 1μm. They are fed perpendicularly toward the brake disc hub surface to acquire the absolute position readings and detected contact displacement of the contact displacement sensors in real time.

[0035] The plane fitting residual determination subunit determines the plane fitting residual R based on the root mean square value of several vertical distances. The plane fitting residual R is determined based on the vertical distance from each measured point to the fitting plane. The vertical distance is determined based on the spatial coordinates of the measured point and the unit normal vector of the hub surface.

[0036] Understandably, the larger the plane fitting residual, the more uneven the hub surface is, such as with burrs or warping, and the worse the coplanarity of the three points. The plane fitting residual completely separates the overall height difference caused by the tilted placement of the workpiece from the local unevenness defects of the workpiece's reference surface itself, quantifying the latter separately. A fitting plane that can represent the current overall posture of the workpiece is determined by the measured points. The fitting plane absorbs all systematic errors caused by tilt and height deviation. Then, the vertical distance from each measured point to this fair surface is calculated. These vertical distances only reflect the degree of local surface defects such as burrs, warping, and pinholes. Finally, the root mean square value of the residual is used to represent the true physical flatness of the reference surface.

[0037] The residual comparison subunit compares the plane fitting residual R with the ideal plane threshold and the graspable limit threshold; Based on the plane fitting residual R being less than or equal to the ideal plane threshold, the residual comparison sub-unit determines that the brake disc is in the first surface state, takes the plane center point (0,0,D) as the gripping height reference, and takes the attitude under the plane unit normal vector n as the gripping attitude reference; during subsequent gripping, the Z-axis of the end gripping mechanism descends to the calculated gripping height, the gripper attitude is finely adjusted to the parallel attitude, and standard clamping is performed.

[0038] Based on the plane fitting residual R being greater than the ideal plane threshold and less than or equal to the graspable limit threshold, the residual comparison sub-unit determines that the brake disc is in the second surface state. The brake disc surface is uneven, so the descent grasping speed of the end gripping mechanism is adjusted. Based on the plane fitting residual R being greater than the graspable limit threshold, the residual comparison sub-unit determines that the brake disc is in the third surface state, indicating that the brake disc surface has serious defects and cannot be grasped.

[0039] During implementation, based on the brake disc being in the second surface state, the residual adjustment subunit determines the deceleration range based on the ratio of the ideal plane threshold to the plane fitting residual R, and reduces the descent and gripping speed of the end gripping mechanism based on the deceleration range; Based on the brake disc being in the third surface state, the residual adjustment subunit stops the gripping cycle, and the Z-axis of the end gripping mechanism is raised to the initial height.

[0040] During implementation, the diameter of the circumcircle of the triangle must be smaller than the minimum diameter of the brake disc hub surface. The flatness detection unit feeds at a speed lower than the conventional rapid traverse speed, such as 5 mm / s, and the displacement sensor transmits readings back in real time at a frequency of 100 Hz.

[0041] When the contact displacement of any one of the three sensors exceeds 0.5mm for the first time, the flatness detection unit determines that the displacement sensor has touched the workpiece surface, immediately stops the feed, and records the absolute position readings of the three sensors and the total descent height of the vertical lifting mechanism at this moment. The absolute position readings include the first position Z1, the second position Z2, and the third position Z3.

[0042] In practice, the reference coordinate system is based on the mounting plane of the sensor, with the center of the three sensors as the origin (0,0,0), and the coordinates of each sensor as (X_i,Y_i) (i=1,2,3). The spatial coordinates of the measured points of the three sensors are Pi=(Xi,Yi,Zi).

[0043] The plane fitting residual determines the sub-unit by solving the spatial plane equation Ax+By+Cz+D=0 based on the spatial coordinates of each measured point. To ensure uniqueness, C=1 is set.

[0044] The plane fitting residual determines the sub-unit. Solve the linear equation system to find A, B, and D. The unit normal vector of the brake disc surface plane is n = (A, B, 1) / (A² + B² + 1). 1 / 2The unit normal vector reflects the spatial tilt attitude of the hub surface.

[0045] In practice, the planar fitting residual determination subunit substitutes the measured point spatial coordinates into |Axi+Byi+Zi+D| / (A²+B²+1). 1 / 2 The vertical distance from each measured point to the fitting plane is determined, and the plane fitting residual R is determined based on the root mean square value of several vertical distances.

[0046] The ideal plane threshold is 50μm; anything smaller than this threshold is considered a precision-machined plane. The gripping limit threshold is 300μm; anything larger is unsuitable for automatic clamping. The ideal plane threshold of 50μm corresponds to the typical flatness tolerance of the wheel hub surface after precision grinding. Under standard processes, the flatness of a qualified semi-finished or finished product reference surface is usually controlled within 0.05mm. As a criterion for the reference surface, the workpiece surface is nearly ideal, and the gripping tool can fit against its rigid surface. The gripping limit threshold of 300μm corresponds to the maximum local defect height within the allowable range of the cast blank wheel hub surface, covering typical flash, slight draft angle error, and the allowable superposition height of small sand holes or oxide scale protrusions. Anything exceeding 300μm means that the positioning reference surface of the workpiece itself is unreliable. Forcibly clamping it with internal support or external clamping will cause positioning misalignment and severely uneven clamping force, leading to excessive wall thickness difference or end face runout problems after subsequent turning.

[0047] Specifically, this invention solves the problem of non-destructive and reliable gripping of a rigid gantry structure when the state of the datum surface of a cast blank is uncertain by integrating active tactile detection with hierarchical decision-making. It utilizes three contact displacement sensors arranged in an equilateral triangle to actively detect the hub surface, using plane fitting residuals to isolate the overall tilt and local defects of the workpiece, achieving an objective quantification of the true physical flatness of the datum surface, rather than relying on visual estimation or weighted guessing. Based on the hierarchical comparison of the plane fitting residuals with dual thresholds, the workpiece surface state is divided into three levels: excellent, compensable, and ungripable. This drives the gripping strategy to autonomously switch between rigid efficiency and compliant safety, balancing production line cycle time and gripping reliability. When there is local unevenness on the datum surface, the descent speed is dynamically adjusted according to the ratio of the plane fitting residual to the ideal threshold, allowing the equipment capacity to adaptively match the workpiece state, avoiding rigid collisions and damage to the positioning datum, thus ensuring the accuracy of subsequent machining from the source.

[0048] In practice, the end-effector gripping mechanism is a gripper equipped with a uniformly distributed force sensor and an independent fine-tuning mechanism. The independent fine-tuning mechanism consists of three miniature Z-axis driven by a voice coil motor, and the gripper is independently servo driven.

[0049] The uniformity coefficient determination subunit determines the instantaneous resultant force based on the sum of the actual pressures of several grippers, and determines the non-uniformity coefficient of the fit based on the ratio of the difference between the maximum and minimum pressure values ​​to the average actual pressure value. It is understandable that a non-uniformity coefficient approaching zero indicates that the three forces are very close and the positioning surface is uniformly attached to the workpiece surface; a non-uniformity coefficient far greater than zero indicates that the force distribution is severely uneven, the positioning surface is raised, and only some areas are bearing the force.

[0050] The bonding comparison sub-unit compares the bonding non-uniformity coefficient with the non-uniformity coefficient threshold curve that becomes increasingly stringent with increasing bonding force.

[0051] Specifically, the purpose of the non-uniformity coefficient is to quantify the uniformity of force distribution using a relative index, rather than judging it by absolute force difference. This is because the magnitude of the absolute force difference depends on the current total preload. At the moment of contact, the resultant force is only a few Newtons, and a difference of one Newton results in a huge tilt. However, when approaching locking, the resultant force is tens of Newtons, and a difference of a few Newtons is still considered uniform. This allows the same judgment criterion to be applied throughout the entire process from initial contact to final locking, adapting to different brake disc specifications and different preload levels, and avoiding the hassle of setting separate force difference thresholds for each working condition. A ramp-shaped threshold curve is used for comparison, allowing the tolerance threshold of the non-uniformity coefficient to dynamically tighten as the instantaneous resultant force increases. This is because the positioning surface bonding is a physical process of first aligning and then compacting. At the initial contact, the resultant force is extremely small, and the gripper plane has not yet established a stable mechanical contact with the workpiece surface. Even slight surface burrs or sensor noise can cause large fluctuations in the force distribution. If the standard of the final strict zone is used at this time, frequent misjudgments will occur, leading to unnecessary attitude adjustments or even machine shutdowns. As the resultant force gradually increases, the gripper positioning surface should gradually straighten under the action of downward pressure, and the force distribution should naturally tend to be balanced. Therefore, a ramp-shaped threshold curve is adopted. The initial loose zone allows a relative difference of 2.0 to safely pass through the unstable stage of initial contact. The mid-term convergence zone requires linear convergence to 0.5 with the resultant force. The final strict zone tightens to 0.2 when approaching the locking force, avoiding early misjudgments and ensuring high uniformity of final bonding.

[0052] Before the instantaneous combined force reaches the target preload, if the non-uniformity coefficient of the bonding is less than the corresponding non-uniformity coefficient threshold of each interval, the bonding comparison sub-unit determines that the positioning ring surface has successfully achieved adaptive bonding. Before the instantaneous combined force reaches the target preload, if the non-uniformity coefficient of the fit is greater than the non-uniformity coefficient threshold corresponding to any current interval, the fit comparison sub-unit determines that the fit is non-uniform, the positioning surface lifts up, the rigid flattening fails, and the attitude adjustment is initiated.

[0053] Understandably, in order to avoid misjudgment due to slight disturbances at the beginning of contact when the force is very small, the threshold curve is designed to be sloping. The non-uniformity coefficient threshold curve includes an initial loose region, a middle convergence region, and a final strict region. Specifically, the initial relaxation zone is the threshold curve range where the instantaneous resultant force is lower than the resultant force threshold range. The gripper is in the initial stage of encountering a burr or a slight high point, and a large difference is allowed. The non-uniformity coefficient threshold is 2.0. The intermediate convergence zone is the threshold curve interval where the instantaneous resultant force is within the resultant force threshold range. The positioning surface should gradually straighten as the pressure is applied, and the non-uniformity coefficient threshold decreases linearly with the increase of the resultant force, from 2.0 to 0.5. The final strict zone is the threshold curve range where the instantaneous resultant force exceeds the resultant force threshold range, which is about to reach the locking force. The fit must be highly uniform, and the non-uniformity coefficient threshold is stable at an extremely low 0.2.

[0054] In this embodiment, the vertical descent mechanism drives the end gripping mechanism to descend to the total descent height, and the final feed begins at a slow speed such as 1 mm / s. The gripping control unit simultaneously monitors the actual gripping pressure F1, F2, F3 and the Z-axis position increment ΔZ of the three force sensors.

[0055] The clamping control unit continuously determines the maximum and minimum actual pressure values ​​of the three grippers, and determines the pressure change rate dF / dt based on the ratio of the difference between the maximum and minimum pressure values; From the initial contact until the instantaneous combined force reaches the preset target preload, the target preload is matched according to the brake disc model, such as 15N. The clamping control unit calculates the current value of the non-uniformity coefficient in each servo cycle, such as 2ms. The uniformity coefficient determination subunit determines the instantaneous resultant force based on the sum of the actual pressures of several grippers, and determines the non-uniformity coefficient of the fit based on the ratio of the difference between the maximum and minimum pressure values ​​to the average actual pressure value. In practice, the average actual pressure is the sum of the average of three actual pressures and a reference constant, wherein the reference constant is 0.01N to prevent the denominator from being zero.

[0056] During the feeding process, the bonding comparison subunit marks the position where the instantaneous resultant force is first detected to be greater than 0.5N as the initial contact point, records the three actual pressures at this moment, and performs dynamic monitoring of bonding uniformity. The resultant force threshold range is (5N, 10N). This range is based on the physical and mechanical characteristics of the contact process between the gripper's positioning ring and the workpiece's hub surface. The lower limit of the threshold range serves as the boundary between the relaxed and convergent regions because before the resultant force falls below this value, the gripper's weight and the sensor's preload are still in a transitional phase of establishing stable contact. The force signal-to-noise ratio is low, and even slight surface oxide scale, sensor drift, or micro-vibration can cause drastic fluctuations in force distribution, making it impossible to determine the mechanical conditions for judging the fit quality. The upper limit of the threshold range serves as the boundary between the convergent and strict regions, corresponding to the mechanical inflection point where the gripper's positioning ring has established rigid contact and compression with the workpiece. At this point, the elastic deformation of the positioning surface is essentially complete, and further force increases will directly translate into pressure on the workpiece body. If the fit remains uneven after this point, it indicates the presence of substantial foreign objects or severe warping that cannot be straightened by simple pressure. Therefore, setting the resultant force threshold range to 5N to 10N creates a clear transition zone, synchronizing the tightening rhythm of the threshold curve with the natural progress of contact mechanics.

[0057] Specifically, when uneven bonding is detected, the bonding adjustment subunit determines the position of the force sensor with the least actual pressure as the low point direction, and controls the micro-motion mechanism on the gripper to tilt in a step of 5μm towards the low point direction until the bonding unevenness coefficient is less than the corresponding unevenness coefficient threshold of the current interval.

[0058] Specifically, this invention achieves adaptive bonding of a rigid gripper to irregular workpiece surfaces through the coordinated use of a bonding non-uniformity coefficient and a slope-shaped dynamic threshold curve. The bonding non-uniformity coefficient quantifies the uniformity of force distribution using a relative ratio, ensuring that the same judgment standard is applied throughout the entire process, from a Newton-level light touch to a tens of Newtons of locking force, eliminating the need to separately calibrate force difference thresholds for different workpiece specifications. The slope-shaped threshold curve conforms to the physical laws of the bonding process. In the initial loose zone, it safely navigates the unstable force signal stage of initial contact with high tolerance. In the middle stage, it linearly tightens as the resultant force increases to guide the positioning surface to gradually align. In the final stage, it tightens as it approaches the locking force to ensure high uniformity of the final bonding, thereby avoiding early misjudgments while guaranteeing the final bonding quality. When bonding non-uniformity is detected, it performs active attitude fine-tuning step by step, guided by the direction of minimum force, so that the gripper positioning surface achieves balanced contact according to the actual concavity and convexity of the workpiece, avoiding local overload or damage to the positioning reference caused by rigid flattening.

[0059] Once the positioning ring surface is confirmed to be successfully fitted, the three jaws open towards the central hole wall in force control mode. The central hole defect unit samples the jaw characteristic parameters of the servo drive motor of each jaw at a frequency of 1kHz. The target current represents the required final balanced clamping force, such as a corresponding 50N clamping force.

[0060] The claw's characteristic parameters include real-time current, real-time speed, and real-time position. The real-time current directly reflects the motor output; the real-time speed is obtained by the encoder differential and reflects the claw opening speed; the real-time position is the encoder position, reflecting the claw's travel distance.

[0061] In each servo cycle of the jaw opening process, the feature parameter determination subunit determines the feature parameters based on the jaw feature parameters of each jaw; Specifically, the characteristic parameters include current surge factor, force displacement stiffness coefficient and instantaneous power characteristic ratio. The current surge factor is determined based on the ratio of the real-time current change value within a sliding time window such as 5ms to the rated current of the motor. The larger the current surge factor, the more violent the current surge at this moment. The force-displacement stiffness coefficient is the ratio of the current increment to the displacement increment, used to distinguish whether it encounters a rigid barrier burr or enters the elastic deformation zone for normal clamping. The current increment and displacement increment are the cumulative current increment and cumulative displacement increment since the first contact. Understandably, during normal clamping, the force-displacement stiffness coefficient gradually increases. As the jaws need to open the hole wall or overcome elastic deformation to generate the rated force from contact, the current increases slowly with the displacement. When the burr is touched, the force-displacement stiffness coefficient will spike instantly. Because the displacement is almost unchanged while the current rises sharply, the burr is blocked by the hard point.

[0062] The instantaneous power characteristic ratio is the product of real-time current and real-time speed. It is used to eliminate non-contact current fluctuations such as current spikes when the motor starts or when static friction switches to dynamic friction. It can be understood that if the real-time current rises but the real-time speed remains normal or only drops slightly, it means that the motor is still doing work and the current rise may be caused by acceleration. Only when the real-time current rises and the real-time speed suddenly drops to near zero does it indicate that the motion is obstructed.

[0063] The criterion comparison subunit compares the feature parameter with the corresponding feature threshold, and determines that the claw has touched a burr or foreign object based on the feature parameter and the corresponding feature threshold meeting the feature criterion. Specifically, if the current surge factor is greater than the factor threshold, the criterion comparison sub-unit determines that the real-time current of the chuck meets the current surge criterion, and the chuck undergoes rigid collision. If the force displacement stiffness coefficient is greater than the coefficient threshold, the criterion compares the sub-units to determine that the chuck meets the high stiffness criterion. The rise in current is not caused by continuous elastic deformation, but by encountering an almost immobile obstacle. If the instantaneous power characteristic ratio is less than the characteristic ratio threshold, the criterion comparison subunit determines that the chuck meets the obstruction confirmation criterion, confirming that the chuck movement has substantially stopped.

[0064] After the criterion comparison subunit determines that the jaw has touched a burr or foreign object based on the feature criteria, the clamping adjustment subunit performs a graded adjustment strategy on the jaw.

[0065] Specifically, the clamping adjustment subunit switches the jaw to torque-limited mode, limiting the maximum allowable torque to 0.7 times the target current, and continues to advance at an extremely low constant speed, such as 0.05 mm / s; Understandably, the purpose of the torque-limited mode is to use a constant small force to try to squeeze out or flatten loose casting flash, surface oxide scale, and other obstacles that can be overcome. If the current surge factor drops below the threshold after the displacement exceeds 0.5mm, the clamping adjustment subunit determines that the obstacle has been overcome, and the claw returns to normal force control mode to continue advancing towards the target current.

[0066] If, after the advancing displacement exceeds 0.5mm, the chuck meets the obstruction confirmation criterion and the real-time current meets the current surge criterion, the clamping adjustment subunit determines that it has encountered an insurmountable hard foreign object, such as an embedded iron bead or severe deformation, and stops the chuck advancing and reverses slightly by a distance of 0.1mm to release the rigid contact stress.

[0067] Understandably, the purpose of reverse micro-retraction is to avoid hard-hitting that could cause deformation of the gripper or damage to the workpiece. It utilizes the friction of the other clamped jaws to temporarily maintain the workpiece's posture. To avoid forcing this jaw to reach its original position target, the final target of this jaw is dynamically modified to float and adhere to the obstacle surface with a force not exceeding the target current. The clamping adjustment subunit synchronously increases the target current of the other two unobstructed jaws within a safe range to compensate for the clamping force lost by this jaw in avoiding burrs, ensuring that the total clamping force remains balanced and reliable.

[0068] When the real-time current of all three jaws enters the ±2% error band of their respective target current and lasts for more than 200ms, the clamping adjustment subunit determines that the fault-tolerant clamping is completed and the workpiece is safely clamped by a dynamically balanced force.

[0069] In this embodiment, the factor threshold is used to indicate that the current surge exceeds 15% of the rated value within 5ms, with an example of 0.15; the coefficient threshold is more than 5 times the force-displacement stiffness coefficient during normal clamping, and the coefficient threshold is obtained through previous clamping learning of the same type of brake disc and stored in the process parameter library; the characteristic ratio threshold indicates that the motor speed has dropped to a state of almost stall, with an example of 0.1 mm / s.

[0070] Understandably, during normal clamping, the jaws contact the elastic hole wall substrate, and the current rises slowly with the increase of displacement. There is a continuous and predictable linear proportional relationship between displacement and current. However, when encountering hard foreign objects such as burrs or iron beads, the movement of the jaws is rigidly blocked for a moment, the displacement almost stops, but the current rises sharply due to the motor stall, forming a transient impact characteristic. Accordingly, the current surge factor threshold is determined based on the typical response bandwidth of the servo motor current loop and the minimum identifiable event of burr collision. Within a 5ms time window, the maximum current increase rate during normal force establishment is limited by the elastic stiffness coefficient of the hole wall metal and will not exceed 5%-8% of the rated current. However, the force establishment time of rigid collisions caused by burrs or foreign objects is determined by the Hertzian contact stiffness of metal to metal and is completed almost instantaneously. The current surge can reach more than 20% of the rated value. Taking 0.15 as the safety dividing line between the two avoids the maximum current fluctuation that may occur during normal clamping and can reliably capture real hard collision events without missing the alarm due to an excessively high threshold. The instantaneous power characteristic ratio threshold corresponds to the physical limit of motion stagnation that can be reliably distinguished by the servo motor in micro-feed mode. When the motor is propelled at low speed in normal force control mode, there is an inherent fluctuation band in the instantaneous speed fed back by its encoder, caused by quantization noise and mechanical backlash, which is no less than 0.2-0.3 mm / s. Only when the pawl encounters an insurmountable rigid obstacle and the driving torque is completely consumed in mechanical deformation rather than displacement will the feedback speed continue to drop below 0.1 mm / s.

[0071] Specifically, the difference between this invention and existing technologies in achieving the target clamping force lies in the fact that when the chuck reaches the target current normally, there may be a real-time decrease in rotational speed and an increase in current. However, the current surge factor is usually small at this time, and the force displacement stiffness coefficient will not spike abnormally because the motor enters torque mode to maintain pressure normally in the final stage. Therefore, the three-dimensional criteria can effectively distinguish between the two. Through the combination of multi-dimensional feature parameter joint criteria and graded fault-tolerant strategy, the accurate identification and adaptive handling of hard foreign objects such as burrs and iron beads in the center hole 7 are achieved. The three-dimensional criteria are cross-validated from three dimensions: current mutation rate, abnormal resistance stiffness, and substantial motion stagnation. The burr collision event is strictly distinguished from the torque pressure maintenance in the final stage of normal clamping, eliminating the defect of easy false alarms in single current threshold judgment. After confirming the burr, the chuck first attempts to push down the loose obstacle that can be broken through with low-speed creep in torque-limited mode. After breaking through, normal clamping is automatically restored. For hard foreign objects that cannot be broken through, the chuck actively retreats slightly to avoid them and dynamically increases the target current of the remaining chucks to compensate for the loss of clamping force, ensuring that the total clamping force is still balanced and reliable. The graded fault tolerance mechanism ensures that when the gripping system encounters defects in the hole wall, it will neither frequently refuse to grip due to excessive conservatism nor damage the workpiece or gripper due to forceful force. This maximizes the success rate of gripping on the first attempt while ensuring gripping safety.

[0072] The threshold negative feedback adjustment unit obtains the final non-uniformity coefficient of the workpiece after it is gripped, and determines the final clamping force balance dispersion of the workpiece based on the final actual current of the three gripper motors.

[0073] It is understandable that in an internal support clamping structure where the three jaws are driven independently, the resistance encountered by each jaw after opening the same distance will inevitably be different due to the non-roundness of the blank's central hole, local flash on the hole wall, or slight elliptical deformation. If the criterion for clamping completion is solely based on each jaw reaching the target position or each jaw's current exceeding a certain absolute threshold, a fundamental hidden danger will arise: one jaw will be pressed against the hole wall and saturated with current, while another jaw will be suspended or in light contact, resulting in an imbalance in the actual clamping force of the three jaws against the hole wall. This off-center loading may not only cause slippage due to vibration during high-speed transport, but more fatally, it will push the workpiece off-center, destroying the positioning reference. Therefore, by reflecting the uniformity of the force distribution of the three jaws through the balance dispersion of the clamping force, the condition for clamping completion is transformed from each jaw having sufficient force to the force of the three jaws being equal.

[0074] Specifically, the calculation method for the clamping force uniformity dispersion is similar to that for the non-uniformity coefficient of the fit, and is determined based on the ratio of the difference between the maximum and minimum current values ​​to the average value of the actual current. In practice, the average actual current is the sum of the average of the three actual currents and the reference constant, which is 0.01N to prevent the denominator from being zero.

[0075] The stability margin determination subunit determines the stability margin index of the current batch based on the final bonding non-uniformity coefficient and the final clamping force balance dispersion of several workpieces in the current batch.

[0076] Specifically, the stability margin determination sub-unit takes the average values ​​of several final bonding non-uniformity coefficients and final clamping force balance dispersion of the highest 10% interval of the current batch, and determines the stability margin index based on the maximum value of the average values.

[0077] Understandably, the stability margin index reflects the degree to which the transfer device is close to its capacity limit during this batch of gripping. A small stability margin index indicates that even the most difficult workpieces are gripped with a uniform force distribution after gripping, meaning the transfer device's gripping capacity is redundant for this batch of workpieces and can handle even more demanding incoming materials. A moderate stability margin index indicates that the transfer device's gripping capacity is well-matched to the severity of this batch of workpieces and operates stably within the safe range. A large stability margin index indicates that although the most difficult batch of workpieces was eventually gripped successfully, the force distribution was quite uneven, and the transfer device was operating at the edge of its capacity limit with a very small margin.

[0078] The margin comparison subunit compares the stability margin index with the ideal margin band. If the stability margin index is lower than the ideal margin band, the margin comparison subunit determines that the transport capacity margin is sufficient, and the threshold adjustment subunit increases the ideal plane threshold by 5μm. If the stability margin index is higher than the ideal margin band, the margin comparison sub-unit determines that the transport capacity margin is insufficient, and the threshold adjustment sub-unit is reduced to capture the limit threshold of 5μm.

[0079] The lower bound of the ideal margin band is 0.05, and the upper bound of the ideal margin band is 0.15. When the average non-uniformity coefficient of the worst 10% of workpieces is less than 0.05, it means that even for the workpieces with the worst gripping conditions in this batch, the force difference between the three force sensors or the three jaws does not exceed 5% of the average value, indicating significant room for efficiency improvement. When the average non-uniformity coefficient of the worst 10% of workpieces exceeds 0.15, it indicates that the force distribution difference of the workpieces is approaching the 20% engineering warning line when the final clamping is completed.

[0080] Specifically, this invention achieves self-optimization of the judgment threshold by statistical feedback of the force distribution quality after the grasping is completed, thus conforming to the actual incoming material state; it constructs a stability margin index based on the final non-uniformity coefficient of the fit and the uniform dispersion of the clamping force, quantifying the ease margin of the grasping capacity relative to the severity of the current incoming material; it has sufficient capacity redundancy, relaxes the ideal plane threshold to improve cycle time; it approaches the limit of the grasping capacity, tightens the graspable limit threshold to ensure safety; it does not rely on the statistics of the previous logical branch attribution, but starts from the final physical contact quality, driving the threshold to evolve gently towards the ideal balance point of efficiency and safety, so that the transfer device can maintain a working state that is both efficient and easy during long-term operation.

[0081] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A transfer device for an automated brake disc production line, characterized in that, include: The transfer device includes a gantry truss support system, a horizontal moving slide, a vertical lifting mechanism, and an end gripping mechanism; The flatness detection unit is used to measure the unit normal vector of the brake disc hub surface by contacting several actual measurement points, determine the plane fitting residual based on the vertical distance from each actual measurement point to the fitting plane to determine the surface state of the brake disc, and adjust the descent and gripping speed of the end gripping mechanism. The clamping control unit is used to determine the initial contact point based on the actual pressure of several grippers of the end gripping mechanism, determine the adhesion unevenness coefficient based on several gripper actual pressures, combine several threshold curve ranges to determine whether the adhesion is uneven, and adjust the gripper posture. The center hole defect unit is used to determine the feature parameters based on the feature parameters of each jaw of the gripper, and to determine the motion condition of the jaw by combining the corresponding feature threshold with the feature criteria, and to adjust the force control mode of the jaw. The threshold negative feedback adjustment unit is used to determine the stability margin index of the current batch based on the final clamping force balance dispersion and the final bonding non-uniformity coefficient after several workpieces are gripped, so as to adjust the threshold of the plane fitting residual.

2. The transfer device for an automated brake disc production line according to claim 1, characterized in that, The flatness detection unit includes, The plane fitting residual determination sub-unit is used to determine the vertical distance based on the spatial coordinates of the measured point and the unit normal vector of the hub surface, and to determine the plane fitting residual based on the root mean square value of several vertical distances. The residual comparison subunit is used to determine the surface condition of the brake disc based on the comparison results between the plane fitting residual and the ideal plane threshold and the graspable limit threshold. The residual adjustment subunit, in response to the surface condition of the brake disc, determines the deceleration magnitude based on the ratio of the ideal plane threshold to the plane fitting residual, and reduces the descent gripping speed of the end gripping mechanism based on the deceleration magnitude.

3. The transfer device for an automated brake disc production line according to claim 2, characterized in that, The residual comparison sub-unit compares the plane fitting residual with the ideal plane threshold and the graspable limit threshold; Based on the plane fitting residual being less than or equal to the ideal plane threshold, the residual comparison sub-unit determines that the brake disc is in the first surface state, determines the plane center point as the gripping height reference, and determines the gripping posture reference based on the unit normal vector. Based on the plane fitting residual being greater than the ideal plane threshold and less than or equal to the graspable limit threshold, the residual comparison subunit determines that the brake disc is in the second surface state. The brake disc surface is uneven, and the residual adjustment subunit reduces the descent grasping speed of the end gripping mechanism. Based on the plane fitting residual being greater than the graspable limit threshold, the residual comparison subunit determines that the brake disc is in the third surface state, the residual adjustment subunit stops the grasping cycle, and the end grasping mechanism is raised to the initial height.

4. The transfer device for an automated brake disc production line according to claim 3, characterized in that, The clamping control unit includes, The uniformity coefficient determination sub-unit is used to determine the instantaneous resultant force based on the sum of the actual pressures of several grippers, and to determine the non-uniformity coefficient of the fit based on the ratio of the difference between the maximum and minimum pressure values ​​to the average actual pressure value. The bonding comparison subunit is used to determine the initial contact point based on the position where the instantaneous resultant force is greater than the reference value, and to determine whether the bonding is uneven based on the comparison result of the bonding unevenness coefficient and the unevenness coefficient threshold curve. The fit adjustment subunit is used to determine the low point direction in response to uneven fit, and adjust the gripper posture based on the low point direction.

5. The transfer device for an automated brake disc production line according to claim 4, characterized in that, The clamping control unit determines the non-uniformity coefficient of the fit during each servo cycle from the initial contact point until the instantaneous combined force reaches the target preload. The non-uniformity coefficient threshold curve includes an initial loose region, a mid-term convergent region, and a final strict region. The corresponding non-uniformity coefficient threshold is determined based on each interval of the matching comparison sub-unit. The initial relaxation zone is the threshold curve range where the instantaneous resultant force is lower than the resultant force threshold range, and the non-uniformity coefficient threshold is set to the maximum value of the range. The intermediate convergence region is the threshold curve interval where the instantaneous resultant force is within the resultant force threshold range, and the non-uniformity coefficient threshold decreases linearly with the increase of the instantaneous resultant force. The final strict region is the threshold curve interval where the instantaneous resultant force exceeds the resultant force threshold range, and the non-uniformity coefficient threshold is set to the minimum value of the interval.

6. The transfer device for an automated brake disc production line according to claim 5, characterized in that, The bonding non-uniformity coefficient of the bonding comparison sub-unit is compared with the corresponding non-uniformity coefficient threshold of each interval; Before the instantaneous combined force reaches the target preload, if the non-uniformity coefficient of the bonding is less than the corresponding non-uniformity coefficient threshold of each interval, the bonding comparison sub-unit determines that the positioning ring surface has successfully achieved adaptive bonding. Before the instantaneous combined force reaches the target preload, if the non-uniformity coefficient of the bonding is greater than the non-uniformity coefficient threshold corresponding to any current interval, the bonding comparison sub-unit determines the non-uniformity of the bonding.

7. The transfer device for an automated brake disc production line according to claim 6, characterized in that, The center hole defect unit includes, The feature parameter determination subunit is used to determine feature parameters based on the feature parameters of each jaw. The jaw feature parameters include real-time current, real-time rotation speed, and real-time position. The feature parameters include current surge factor, force-displacement stiffness coefficient, and instantaneous power characteristic ratio. The criterion comparison subunit is used to determine whether the claw has touched a burr or a foreign object based on the feature parameter and the corresponding feature threshold conforming to the feature criterion. The clamping adjustment subunit is used to switch the clamp to torque-limited mode for low-speed advancement based on the determination that the clamp has touched a burr or foreign object. It restores the normal force control mode when the current surge factor drops below the factor threshold after the advancement displacement exceeds the displacement distance. It stops the clamp advancement and reverses slightly when the clamp meets the obstruction confirmation criterion and the real-time current meets the current surge criterion after the advancement displacement exceeds the displacement distance.

8. The transfer device for an automated brake disc production line according to claim 7, characterized in that, The criterion comparison sub-unit determines that the real-time current of the chuck meets the current surge criterion based on the current surge factor being greater than the factor threshold. The criterion comparison sub-unit determines that the chuck meets the high stiffness criterion based on the force displacement stiffness coefficient being greater than the coefficient threshold. The criterion comparison sub-unit determines that the chuck meets the obstruction confirmation criterion based on the instantaneous power characteristic ratio being less than the characteristic ratio threshold.

9. The transfer device for an automated brake disc production line according to claim 8, characterized in that, The current surge factor is determined based on the ratio of the real-time current change value to the rated current within the sliding time window, and is used to determine the severity of the current surge. The force-displacement stiffness coefficient is determined based on the ratio of current increment to displacement increment, and is used to distinguish between the gripping conditions of rigid barrier burrs and normal clamping in elastic deformation zones. The instantaneous power characteristic ratio is determined based on the product of real-time current and real-time rotation speed, and is used to eliminate current spikes during non-contact current fluctuations.

10. The transfer device for an automated brake disc production line according to claim 9, characterized in that, The threshold negative feedback adjustment unit includes, The stability margin determination sub-unit is used to determine the stability margin index based on the average maximum value of the final bonding non-uniformity coefficient and the final clamping force balance dispersion within the highest range of several workpieces in the current batch. The margin comparison sub-unit is used to compare the stability margin index with the ideal margin band. If the stability margin index is lower than the ideal margin band, the transfer capacity margin is determined to be sufficient. If the stability margin index is higher than the ideal margin band, the transfer capacity margin is determined to be insufficient. The threshold adjustment subunit is used to increase the ideal plane threshold when the transport capacity margin is sufficient, and to decrease the graspable limit threshold when the transport capacity margin is insufficient.

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