A robot manipulator pneumatic joint automatic docking control method and system

Abstract

The application relates to the technical field of mechanical arm control, and discloses a robot mechanical arm pneumatic joint automatic butt joint control method and system. The method comprises the following steps: continuously sampling an insertion force displacement sequence in a positioning pin insertion process; integrating the insertion displacement to obtain mechanical insertion work; substituting into a true connected mapping to obtain a pneumatic response expected value, obtaining a measured value from a first-order difference peak value of a gas circuit gas pressure, and screening mechanical sticking, sealing pollution or true connected butt joint state types according to the mechanical insertion work and the upper and lower limits and in combination with a deviation direction; and obtaining a butt joint result according to a butt joint state type matching recovery strategy. The application improves the accuracy of fault cause identification in the automatic butt joint process of the pneumatic joint and the targeting degree of recovery processing after butt joint failure.

Description

Technical Field

[0001] This application relates to the field of robotic arm control technology, and in particular to an automatic docking control method and system for pneumatic joints of robotic arms. Background Technology

[0002] Industrial robots need to frequently switch between end tools such as welding torches, grinding tools, cleaners, and different pneumatic grippers during welding operations. Therefore, existing technologies generally employ pneumatic methods to achieve rapid end tool changes and airflow connection. CN109849042A discloses a robot end tool quick-change device, including a tool connector fixed to a frame and a robot end connector. The tool connector is fixed to the frame via a pneumatic device, and the robot end connector is pneumatically connected to the tool connector. The robot actuator uses this to switch between peripheral tools such as welding torches, grinding tools, and laser cleaners, and complete airflow connection. CN102189551B discloses a robot system and handling method, which includes an inspection device to check the robot's holding status of the workpiece. If the holding status is acceptable, the robot moves the workpiece to the next process; if unacceptable, the workpiece is returned to a temporary placement table and held again, thus constituting a pass / fail judgment and retry mechanism for the holding action. These solutions already possess corresponding means for mechanical changing of end tools, physical airflow connection, and judgment of whether the action result is acceptable.

[0003] However, the existing technologies mentioned above only determine the success of pneumatic connection by whether the action is completed or whether the state is maintained correctly. CN109849042A only completes the pneumatic connection between the tool connector and the robot end effector without identifying the quality of the pneumatic connection. Although the inspection device in CN102189551B provides a binary judgment of pass or fail, it does not further distinguish the cause of failure. There is a large amount of spatter and dust at the welding site. Foreign objects falling into the positioning hole can prevent the positioning pin from being inserted properly. Welding slag and dust adhering to the sealing surface of the pneumatic joint can cause poor sealing. Both of these situations manifest as weak or slow pneumatic pressure buildup. Existing solutions cannot distinguish whether the failure is due to improper mechanical insertion or contamination of the sealing surface, and can only generally determine that the connection is unqualified.

[0004] Because existing solutions can only determine whether the connection is successful but not the cause of failure, the first problem arises: two very different faults—incomplete mechanical connection and contamination of the sealing surface—present the same weak pressure phenomenon in the pneumatic channel, and air pressure alone cannot distinguish between them. Since a single air pressure signal is insufficient to differentiate the cause, a physical quantity reflecting the actual degree of mechanical connection completion needs to be introduced to jointly determine the connection with the air pressure signal. This leads to the second problem: how to establish a comparable correlation between the degree of mechanical connection completion and the pneumatic pressure performance. Based on the relationship, the two types of faults are distinguished by whether the mechanical connection meets the standard and by observing the deviation of the air pressure. Furthermore, since the causes of the two types of faults are different, their elimination methods should also be different. Mechanical jamming requires removing the pin, clearing foreign objects from the hole, and then reinserting it. Sealing contamination requires blowing the sealing surface while maintaining the connection. This leads to the third issue, which is how to apply a recovery action that matches the cause of the fault after it has been identified, rather than repeating the same retry action for all non-conforming situations as in CN102189551B, which leads to repeated failures. Summary of the Invention

[0005] This application provides an automatic docking control method and system for pneumatic joints of robotic arms, which solves the problem that two faults, namely mechanical insertion failure and sealing surface contamination, cannot be distinguished in the pneumatic channel during welding, and docking failure can only be generally judged without targeted treatment. It improves the accuracy of fault cause identification and the targeted nature of recovery treatment after docking failure during the automatic docking process of pneumatic joints.

[0006] In a first aspect, this application provides an automatic docking control method for pneumatic joints of a robot manipulator, the method comprising: Step S1: Continuously sample the insertion force and displacement during the insertion process of the positioning pin to obtain the insertion force-displacement sequence; Step S2: Integrate the insertion displacement with respect to the insertion force displacement sequence to obtain the mechanical insertion work; Step S3: Substitute the mechanical insertion work into the true connection mapping to obtain the expected value of the aerodynamic response. Obtain the measured value of the aerodynamic response from the first-order differential peak value of the joint air pressure. Based on the level of the mechanical insertion work and the lower limit of the insertion work, and combined with the deviation direction of the measured value of the aerodynamic response relative to the expected value of the aerodynamic response, filter to obtain the docking state type. The docking state type includes mechanical jamming where the mechanical insertion work is lower than the lower limit of the insertion work, sealing contamination where the mechanical insertion work is not lower than the lower limit of the insertion work and the measured value of the aerodynamic response is lower than the expected value of the aerodynamic response, and true connection where the mechanical insertion work is not lower than the lower limit of the insertion work and the deviation between the measured value of the aerodynamic response and the expected value of the aerodynamic response is within the consistency tolerance. Step S4: Match the corresponding recovery strategy according to the docking status type to obtain the docking result of the positioning pin and the connector air passage.

[0007] Secondly, this application provides an automatic docking control system for pneumatic connectors of a robot manipulator, the automatic docking control system for pneumatic connectors of a robot manipulator comprising: The sampling module is used to continuously sample the insertion force and displacement during the insertion process of the positioning pin to obtain the insertion force-displacement sequence. The integration module is used to integrate the insertion displacement with respect to the insertion force-displacement sequence to obtain the mechanical insertion work; The filtering module is used to substitute the mechanical insertion work into the true connection mapping to obtain the expected value of the aerodynamic response, obtain the measured value of the aerodynamic response from the first-order differential peak value of the joint air pressure, and filter out the docking state type based on the level of the mechanical insertion work and the lower limit of the insertion work, combined with the deviation direction of the measured value of the aerodynamic response relative to the expected value of the aerodynamic response. The docking state type includes mechanical jamming where the mechanical insertion work is lower than the lower limit of the insertion work, sealing contamination where the mechanical insertion work is not lower than the lower limit of the insertion work and the measured value of the aerodynamic response is lower than the expected value of the aerodynamic response, and true connection where the mechanical insertion work is not lower than the lower limit of the insertion work and the deviation between the measured value of the aerodynamic response and the expected value of the aerodynamic response is within the consistency tolerance. The matching module is used to match the corresponding recovery strategy according to the docking status type to obtain the docking result between the positioning pin and the connector air passage.

[0008] Thirdly, an automatic docking control device for pneumatic joints of a robot is provided, comprising: a memory and at least one processor, wherein the memory stores instructions; the at least one processor invokes the instructions in the memory to cause the automatic docking control device for pneumatic joints of a robot to execute the above-described automatic docking control method for pneumatic joints of a robot.

[0009] Fourthly, a computer-readable storage medium is provided, wherein instructions are stored therein, which, when executed on a computer, cause the computer to perform the above-described automatic docking control method for the pneumatic joint of a robot manipulator.

[0010] In the technical solution provided in this application, the insertion force-displacement sequence obtained by pairing insertion force and insertion displacement records the complete force and stroke of the positioning pin from contact with the positioning hole opening to the displacement of the pin in place, rather than just taking a single switching quantity of whether the pin is in place or not. This allows the completion quality of the insertion action to be quantitatively identified. On this basis, the mechanical insertion work obtained by integrating the insertion force-displacement sequence with the insertion displacement integrates the discrete stroke signal and force signal into a physical quantity that reflects the actual insertion depth and the degree of obstruction of the pin. When there is welding slag in the positioning hole, causing the pin to be obstructed or the stroke to be insufficient, this quantity will decrease accordingly, thus providing an objective mechanical basis for subsequent differentiation of fault causes. Unlike existing methods that rely solely on air pressure to determine docking success or failure, this application substitutes the mechanical insertion work into the true connection mapping to obtain the expected value of the aerodynamic response. Then, it uses the first-order differential peak value of the air pressure in the air path as the measured value of the aerodynamic response. The two constitute a comparable relationship between the expected and measured values ​​of the mechanical side and the aerodynamic side. By using the mechanical insertion work and the lower limit of the insertion work, and combining the direction of the aerodynamic response deviation, it distinguishes between two faults that are both manifested as weak pressurization in the air pressure channel and cannot be distinguished by air pressure alone: ​​mechanical insertion failure and sealing surface contamination. This allows docking failure to be traced back to its cause rather than being judged in a general way.

[0011] In specific application scenarios where welding grippers are frequently replaced and welding slag and dust easily intrude into pin holes and sealing surfaces, this algorithm uses the correspondence between the work done under clean operating conditions and the peak rate of air pressure rise as a reference benchmark. It takes the work done on the mechanical side as a prerequisite for measuring the commensurateness of the pneumatic response. This prerequisite separates the two types of faults that overlap in the air pressure dimension into the mechanical insertion work dimension. Outside of this scenario, the algorithm loses its discriminative meaning. Therefore, the inherent combination of the algorithm's features and the application scenario constitutes the focal point of its creative contribution. Furthermore, the technical feature of matching the identified docking state type with the corresponding recovery strategy allows for targeted treatment of mechanical jamming (pin removal, hole cleaning, and re-insertion) and sealing contamination (maintaining insertion and purging the sealing surface), rather than repeating the same action for all failures. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of one embodiment of the automatic docking control method for the pneumatic joint of a robot manipulator in this application. Figure 2 This is a schematic diagram of the single-pin insertion force-displacement curve and trapezoidal integral in an embodiment of this application; Figure 3This is a schematic diagram of the docking status type discrimination partition in the embodiments of this application. Detailed Implementation

[0014] This application provides an automatic docking control method and system for pneumatic joints of a robot manipulator. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" or "having" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0015] For ease of understanding, the specific process of the embodiments of this application is described below. Please refer to [link / reference]. Figure 1 One embodiment of the automatic docking control method for the pneumatic joint of the robot manipulator in this application includes: Step S1: Continuously sample the insertion force and displacement during the insertion process of the positioning pin to obtain the insertion force-displacement sequence; Specifically, from the moment the conical guide section touches the locating hole opening until it reaches its final displacement, the insertion force measured by the pin seat force sensor continuously changes with the stroke. The insertion force displacement sequence obtained by accumulating this force segment by segment along the insertion displacement carries the force and stroke of the entire insertion process, unlike existing automatic tool changers that only take a single switching quantity when the pin is in place. When the hole is clean and the pin sinks straight down, the force is stable; when there is welding slag embedded at the bottom of the hole, the force rises sharply in the middle. This continuous recording throughout the process allows the location and severity of the obstruction to be identified from the force trend, rather than just knowing the two discrete states of whether it is in place or not.

[0016] Step S2: Integrate the insertion displacement with respect to the insertion force-displacement sequence to obtain the mechanical insertion work; Specifically, the mechanical insertion work obtained by accumulating the insertion force displacement sequence interval by interval along the insertion displacement corresponds to the energy dissipated by the pin overcoming the guiding resistance of the conical surface and the friction of the sidewall. It is a comprehensive measure of the actual insertion depth and the degree of obstruction, and does not refer to arbitrary mechanical work. When the pin sinks straight to the bottom, this value falls within a stable range; when the pin is obstructed prematurely or the stroke is insufficient, it slides down significantly. Its lower limit is set at 420 millijoules, based on the lower boundary of the work value fluctuation band obtained from dozens of qualified insertions under clean working conditions. Below this value, it indicates that the pin has not sunk to the bottom.

[0017] Step S3: Substitute the mechanical insertion work into the true connection mapping to obtain the expected value of the aerodynamic response. Obtain the measured value of the aerodynamic response from the first-order differential peak value of the gas pressure in the joint air path. Based on the level of the mechanical insertion work and the lower limit of the insertion work, and combined with the deviation direction of the measured value of the aerodynamic response relative to the expected value of the aerodynamic response, screen to obtain the docking state type. The docking state types include mechanical jamming where the mechanical insertion work is lower than the lower limit of the insertion work, sealing contamination where the mechanical insertion work is not lower than the lower limit of the insertion work and the measured value of the aerodynamic response is lower than the expected value of the aerodynamic response, and true connection where the mechanical insertion work is not lower than the lower limit of the insertion work and the deviation between the measured value of the aerodynamic response and the expected value of the aerodynamic response is within the consistency tolerance. Specifically, the true connectivity mapping is not an empirically applied formula, but rather a monotonically increasing straight line obtained by repeatedly connecting and recording the mechanical insertion work and the peak rate of air pressure rise after each connection on a clean joint free of welding slag and oil before installation. This is achieved through least-squares fitting of sample pairs, with a slope of 0.008 MPa / mJ and an intercept of 0.01 MPa / mJ. This means that the deeper the pin is inserted, the more work is done, resulting in a more complete seal and faster airflow. The expected aerodynamic response value is calculated by substituting the mechanical insertion work into this straight line. The air pressure is sampled at millisecond intervals from the pin's insertion point, and the maximum value of the pressure difference between two adjacent points is taken as the measured aerodynamic response value. The difference between these two values ​​yields the deviation. When the pin has sunk into place (meaning the mechanical insertion power is not lower than the lower limit), but the measured value is far lower than expected and the deviation exceeds the consistency tolerance of 0.4 MPa per second, it indicates that the pin is in place but the sealing surface is raised by welding slag, resulting in air leakage, which is judged as sealing contamination. When the mechanical insertion power is already lower than the lower limit, it indicates that the pin has not sunk into place and the joint is not aligned, which is judged as mechanical jamming. Thus, the two types of faults, which both manifest as insufficient pressure in the final air pressure, are separated.

[0018] Step S4: Match the corresponding recovery strategy according to the docking status type to obtain the docking result of the positioning pin and the connector air circuit.

[0019] Specifically, if seal contamination is detected, the positioning pin is kept in the inserted state and the sealing surface of the joint is purged before the air pressure is re-measured. If mechanical jamming is detected, the pin is removed, the hole is cleaned, and the joint is re-pressed and the mechanical insertion work is recalculated. The two types of faults correspond to two different recovery actions with different causes, instead of retrying all of them. The cycle continues until the deviation falls within the consistency tolerance, at which point the pneumatic gripper is released and the docking is completed. If the deviation does not fall within the upper limit after continuous retrying, an alarm is triggered and the docking fails, thus forming a docking closed loop that corrects errors based on the cause of the fault.

[0020] In one specific embodiment, step S1 includes: From the moment the tapered guide section of the self-positioning pin contacts the orifice of the positioning hole, the pin seat force sensor of the self-positioning pin and the displacement sensor at the bottom of the positioning hole are synchronously triggered and sampled according to the set sampling period to obtain the insertion force sampling value and the insertion displacement sampling value with time index. The single-pin insertion force and displacement sampling points are obtained by pairing and combining the same time index of the insertion force sampling value and the insertion displacement sampling value. Based on the positioning displacement threshold and the insertion timeout duration, the sampling cutoff of the single pin insertion force displacement sampling points is determined. The single pin insertion force displacement sampling points before reaching the positioning displacement threshold or the insertion timeout duration are arranged in time index order to obtain the single pin insertion force displacement subsequence. The single-pin insertion force displacement subsequence of each locating pin is aggregated by pin to obtain the insertion force displacement sequence.

[0021] Specifically, the tapered inlet section of the locating pin is the conical transition surface of the pin head. It enters the locating hole opening before the cylindrical section of the pin. The moment it touches the opening is taken as the zero point of sampling. Thereafter, a sampling cycle is taken every 1 millisecond. In each cycle, the current insertion force is read from the force sensor embedded in the pin seat, and the current insertion displacement is read from the displacement sensor buried at the bottom of the locating hole. The two readings share the same time index that increases with the cycle starting from the zero point. The sampling period is 1 millisecond because the entire journey of the locating pin from contacting the opening to sinking to the bottom is only a few hundred milliseconds. A 1-millisecond cycle can capture a sufficiently dense number of points without missing the inflection point when the pin experiences a sudden change in force.

[0022] Pairing a pin insertion force reading with a pin insertion displacement reading with the same time index creates a single pin insertion force-displacement sampling point. This point records how deep a pin was inserted and the amount of resistance it encountered at a given moment. Sampling is not indefinite. Once the hole bottom displacement sensor reading reaches 12 mm, it is determined that the pin has reached the design depth, and sampling stops. The 12 mm is taken from the effective insertion stroke of the cylindrical section of the pin within the positioning hole. When the pin is properly positioned, the displacement covers exactly this segment. If welding slag in the hole blocks the pin, preventing the displacement from reaching 12 mm, an 800-millisecond insertion timeout is used as a fallback. Sampling stops once 800 milliseconds have elapsed, regardless of whether the pin is properly positioned. The 800-millisecond timeout is set to allow for several hundred milliseconds throughout the normal insertion process, preventing continuous sampling if the pin is stuck. Arrange all single-pin insertion force displacement sampling points from time zero until the triggering of any of the above-mentioned cutoff conditions in ascending order of time index to obtain the single-pin insertion force displacement subsequence of the pin. Each of the four positioning pins independently completes the above sampling to obtain four subsequences. Then, collect these four subsequences together according to the pin number to synthesize a single insertion force displacement sequence that covers the force and position data of the four pins throughout the entire process.

[0023] In one specific embodiment, step S2 includes: Based on the pin-by-pin decomposition of the insertion force displacement sequence, the single-pin insertion force displacement subsequence of each positioning pin is obtained; Based on the insertion displacement difference between two adjacent sampling points in the single pin insertion force displacement subsequence, the single pin insertion force displacement subsequence is divided into adjacent intervals to obtain the single pin insertion interval. The average value of the insertion force at the two sampling points at the beginning and end of the single pin insertion interval is multiplied by the difference in insertion displacement of the single pin insertion interval to obtain the work increment of the single pin interval. The work increment of each single pin interval for the same positioning pin is accumulated by pin to obtain the mechanical insertion work of the single pin. The mechanical connection work is obtained by arithmetically averaging the single-pin mechanical connection work of each locating pin.

[0024] Specifically, the previously synthesized insertion force displacement sequence is restored into four single-pin insertion force displacement subsequences according to the pin number. Each subsequence is a series of single-pin insertion force displacement sampling points arranged by time index from the contact hole to the cutoff time of a certain positioning pin. Within a subsequence, the insertion displacement moves through a small increment between adjacent sampling points. This small increment is a single-pin insertion interval. The entire subsequence is composed of several single-pin insertion intervals connected end to end. The work done by the locating pin in this short segment is equal in magnitude to the product of the displacement increment and the insertion force on the pin in this segment. Since the insertion force smoothly changes from the starting value to the ending value in a short segment, the arithmetic mean of the insertion forces at the starting and ending sampling points is taken as the equivalent insertion force of this short segment. Multiplying this by the difference in insertion displacement gives the work increment of the single pin interval. This algorithm of taking the mean and multiplying is called trapezoidal numerical integration, which cuts the area under the curve of force changing with displacement into many narrow trapezoids and calculates them piece by piece.

[0025] The incremental work of each individual pin in the same positioning pin's insertion interval is accumulated sequentially along the insertion displacement. The total amount obtained is the mechanical insertion work of that pin. It corresponds to all the energy dissipated by the pin from the contact hole to the cutoff moment, overcoming the guiding resistance of the conical surface and the friction of the side wall. This value is large when the pin sinks straight to the bottom, and small when the pin is blocked by welding slag and the stroke is insufficient or the obstruction increases sharply. The mechanical insertion work of each of the four positioning pins is accumulated to obtain four mechanical insertion works. The arithmetic mean of these four values ​​is obtained. The average is taken because the four pins are distributed at the four corners of the robot arm mounting base. Occasionally, a local burr or individual sampling jump of a single pin will distort its mechanical insertion work. After averaging the four pins, such occasional deviations are diluted. The obtained mechanical insertion work reflects the overall insertion status of the four pins together, and the dimension is millijoules.

[0026] Figure 2 This is a schematic diagram of the single-pin insertion force-displacement curve and trapezoidal integral in an embodiment of this application. Figure 2The graph shows the curve of the insertion force of a single locating pin from the point where it contacts the locating hole in the conical guide section to the point where it reaches its final displacement, as a function of the insertion displacement. The horizontal axis represents the insertion displacement in millimeters, and the vertical axis represents the insertion force in Newtons. The dots on the curve are sampling points of the single pin insertion force displacement obtained according to the set sampling period. The insertion displacement between two adjacent sampling points constitutes a single pin insertion interval. The area of ​​the narrow strip obtained by multiplying the average insertion force of the two sampling points at the beginning and end of each single pin insertion interval by the difference in the insertion displacement of that interval is the single pin interval work increment. The sum of all the narrow strip areas is the single pin mechanical insertion work of the locating pin. The vertical dashed line in the figure marks the point where the final displacement is 12 millimeters. When the locating pin sinks straight to this displacement, the insertion force rises steadily with the stroke and rises sharply at the end of the guide section due to the conical surface pressing against it. The accumulated single pin mechanical insertion work falls above the acceptable range of clean working conditions.

[0027] In one specific embodiment, step S3, substituting the mechanical plugging work into the true connectivity mapping to obtain the expected aerodynamic response value, includes: Based on the mechanical insertion work of multiple dockings under clean working conditions and the peak rate of air pressure rise after the air circuit is pressurized, a sample pair of mechanical insertion work and peak rate of air pressure rise is formed. The sample pairs are fitted with a monotonically increasing straight line to the input least squares to obtain a true connectivity map that includes the true connectivity slope and the true connectivity intercept. Substituting the mechanical plugging work into the true connectivity mapping, and then performing a linear conversion by multiplying the mechanical plugging work by the true connectivity slope and adding it to the true connectivity intercept, we obtain the expected value of the aerodynamic response.

[0028] Specifically, the true connectivity mapping is calibrated before installation and commissioning. Under clean conditions—where the positioning holes are thoroughly cleaned and the sealing surfaces of the joints are wiped clean to remove welding slag and oil—the positioning pins are repeatedly docked dozens of times. For each docking, the mechanical insertion work calculated using a trapezoidal integral is recorded, along with the peak rate of air pressure rise during the joint's air passage pressurization. This peak rate is obtained by dividing the pressure difference between two adjacent points sampled at millisecond intervals by the sampling period and taking the maximum value; it characterizes the fastest inflation rate once the air passage is connected. These two values ​​from each docking constitute a sample pair. Dozens of dockings accumulate dozens of sample pairs, distributed on a plane with the mechanical insertion work as the horizontal axis and the peak rate of air pressure rise as the vertical axis. Under clean conditions, the deeper the pin is inserted, the more work is done, the tighter the sealing surface fits, and the faster the air passage is pressurized. Therefore, these sample pairs are distributed along a straight line from the lower left to the upper right.

[0029] This batch of sample pairs is fed into the least squares fitting algorithm. Least squares is an algorithm that finds a straight line from the scattered points that minimizes the sum of the squares of the vertical distances from each sample point to the straight line. The resulting straight line is the true connectivity map, and its slope is called the true connectivity slope, which is set to 0.008 MPa per millijoule. This means that for every 1 millijoule increase in mechanical plugging work, the peak rate of air pressure rise under clean conditions increases by 0.008 MPa per second. Its intercept on the vertical axis is called the true connectivity intercept, which is set to 0.01 MPa per second. It is the intersection of the vertical axis of the straight line when the mechanical plugging work approaches zero. Both parameters are calculated from the distribution of this batch of clean sample pairs rather than being manually specified. Once the calibration is completed, these two parameters are stored in the control unit. When performing actual docking, the mechanical insertion work calculated for that time is taken. The mechanical insertion work is multiplied by the true connection slope and then the true connection intercept is added to perform a linear conversion. The resulting value is the expected value of the aerodynamic response. It represents the peak pressure rate that the air passage should reach if the sealing surface is intact during the current docking. It serves as a reference benchmark to measure whether the actual pressure rate is commensurate.

[0030] In one specific embodiment, step S3, obtaining the measured aerodynamic response value from the first-order differential peak value of the joint air pressure, includes: Starting from the moment the self-positioning pin reaches its displacement, the air pressure in the joint air circuit is continuously sampled according to the set sampling period to obtain an air pressure sequence with time index; The pressure rise rate sequence is obtained by performing first-order difference processing based on the ratio of the pressure difference between two adjacent sampling points in the pressure sequence to the sampling period. The pressure rise rate sequence is filtered by value magnitude to obtain the peak value of the pressure rise rate with the largest value, and the peak value of the pressure rise rate is used as the measured value of the aerodynamic response.

[0031] Specifically, the instant the displacement sensor reading at the bottom of the positioning pin hole reaches the designated displacement indicates that the pin has sunk to the designed depth, the female connector of the pneumatic joint has been fully engaged with the male connector located on the robot wrist mount, and the air passage is now open. This instant is taken as the zero moment for air pressure sampling. Before this point, the pin is still sinking, the joint is not yet engaged, and the air passage is either not open or partially open. The pressure sampled does not reflect the true filling pressure, so sampling must begin only after the pin is fully engaged. Starting from the zero moment, the air pressure in the pneumatic gripper's air intake branch is read every 1 millisecond. Each reading is associated with a time index that increments sequentially from the zero moment. This series of indexed pressure readings constitutes the air pressure sequence. The sampling period is 1 millisecond because it only takes tens of milliseconds for the air passage to go from being open to being fully filled. A 1-millisecond interval ensures that a sufficiently dense number of points are collected during the rapid pressure rise without missing the moment of the fastest rise.

[0032] In the pressure sequence, the pressure difference at each adjacent sampling point is obtained by subtracting the pressure at the previous sampling point from the pressure at the next adjacent sampling point. This difference is then divided by the 1-millisecond sampling period. The resulting value represents the rate at which the pressure rises with time at that point. This process is repeated for each pair of adjacent points in the entire sequence, resulting in a series of rate values, which is the pressure rise rate sequence. This algorithm of subtracting adjacent points and dividing by the period is the first-order difference, which transforms the pressure-time curve into a curve whose slope changes with time. The pressure rises sharply and at its maximum rate at the instant the gas path is opened. When the sealing surface is blocked by welding slag and leaks, the pressure rises slowly through seepage, and the rate remains relatively low. The highest value in the sequence of air pressure rise rates is selected as the peak value of the air pressure rise rate. Instead of the final air pressure value after full filling, this value is used as the measured value of the aerodynamic response. The reason is that even if the air passage is leaking due to sealing contamination, the infiltrated air may still cause the final value to slowly climb to a supply pressure close to 0.6 MPa. Looking at the final value alone will misjudge that the filling pressure is normal. However, the peak value of the rise rate is already lowered by the leaking air pressure at the moment of connection, which can expose the poor sealing on the spot. The obtained measured value of the aerodynamic response is then subtracted from the expected value of the aerodynamic response to calculate the deviation.

[0033] In one specific embodiment, in step S3, based on the relative levels of the mechanical insertion work and the lower limit of the insertion work, and considering the direction of deviation between the measured aerodynamic response value and the expected aerodynamic response value, the docking state type is selected, including: The aerodynamic response deviation is obtained by processing the difference between the measured aerodynamic response value and the expected aerodynamic response value. The mechanical plugging power is compared with the lower limit of the plugging power, and the aerodynamic response deviation is compared with the consistency tolerance in terms of amplitude to obtain the comparison results. The docking status type is obtained by screening the comparison results. The docking status types include: mechanical jamming corresponding to mechanical insertion work being lower than the lower limit of insertion work; sealing contamination corresponding to mechanical insertion work not being lower than the lower limit of insertion work and aerodynamic response deviation being negative and exceeding the consistency tolerance; and true connection corresponding to mechanical insertion work not being lower than the lower limit of insertion work and aerodynamic response deviation being within the consistency tolerance.

[0034] Specifically, the pneumatic response deviation is obtained by subtracting the expected pneumatic response value from the measured pneumatic response value. The measured value is the peak actual charging rate at the moment the air passage is opened, and the expected value is the rate that should be reached under the assumption that the insertion depth is intact. The deviation obtained by subtracting the two has a positive or negative sign. A negative deviation indicates that the measured charging is slower than expected and there is abnormal leakage in the air passage. A deviation close to zero indicates that the measured value matches the expectation and the air passage is charged normally. First, the mechanical insertion work is compared with the lower limit of 420 millijoules. 420 millijoules is the lower boundary of the fluctuation range of the work value obtained by qualified insertion under clean working conditions. When the pin sinks straight to the 12 mm displacement position, the work must fall above this value. When the pin is blocked by the welding slag in the hole and the stroke is insufficient or obstructed in the middle, the work falls below this value. This comparison is used to determine whether the pin has truly sunk to the position mechanically. Next, take the absolute value of the aerodynamic response deviation and the amplitude of the consistency tolerance of 0.4 MPa per second. The 0.4 MPa per second is taken from the normal fluctuation bandwidth of the measured peak rate around the expected value under clean working conditions. If the deviation falls within this band, it is considered that the measured value is consistent with the expected value.

[0035] Two comparisons yielded three results. If the mechanical insertion power drops below 420 mJ, regardless of the pneumatic circuit performance, it's considered mechanical jamming because the pin isn't fully seated and the male and female ends of the pneumatic connector aren't properly aligned. In this case, the pneumatic circuit pressurization is abnormal, and the root cause lies on the mechanical side. If the mechanical insertion power is not less than 420 mJ, indicating the pin is fully seated, but the pneumatic response deviation is negative and its absolute value exceeds 0.4 MPa / s, it's considered seal contamination. This is because the pin should be in place and charging should be fast, but the actual measurement is significantly slower. The only cause is that the connector sealing surface is blocked by welding slag or dust, causing leakage during charging. If the mechanical insertion power is not less than 420 mJ and the pneumatic response deviation is within ±0.4 MPa / s, it's considered true connection, the pin is in place, the pressurization rate is commensurate with the insertion depth, and the seal is intact. Mechanical jamming and seal contamination both manifest as insufficient pressure rise in the final gas pressure value of the gas path. It is difficult to distinguish between the two by looking at the gas pressure alone. In this case, the flow was first divided based on whether the mechanical connection function met the standard. If it met the standard, the direction of deviation was then examined. In this way, the two types of faults with different causes were distinguished on the spot, and the obtained connection status type was sent to match the corresponding recovery strategy.

[0036] Figure 3 This is a schematic diagram of the docking status type discrimination partition in the embodiments of this application. Figure 3The diagram illustrates a docking status type discrimination zone with mechanical insertion work as the horizontal axis (mJ) and aerodynamic response deviation as the vertical axis (MPa / s). The vertical solid line on the horizontal axis represents the lower limit of insertion work (420 mJ), and the two horizontal dashed lines on the vertical axis represent the consistency tolerance (±0.4 MPa / s). Triangular points represent mechanical jamming (mechanical insertion work below the lower limit), square points represent sealing contamination (mechanical insertion work not below the lower limit, aerodynamic response deviation negative, and exceeding the consistency tolerance), and circular points represent true connectivity (mechanical insertion work not below the lower limit, aerodynamic response deviation within the consistency tolerance). Mechanical jamming and sealing contamination points are both located in the area below the negative deviation on the vertical axis. They are divided into different zones based on whether the mechanical insertion work crosses the lower limit on the horizontal axis. This demonstrates how two types of faults, both exhibiting weak gas pressure, can be distinguished based on the mechanical insertion work.

[0037] In one specific embodiment, step S4 includes: When the docking status type is true connection, the pneumatic gripper control valve is enabled, and the docking result between the positioning pin and the connector air circuit is considered as docking complete. When the docking state type is sealed contamination, the sealing surface of the joint is purged and dusted while keeping the positioning pin insertion state unchanged. The joint after dust removal is obtained, and the air pressure of the joint air passage after dust removal is re-obtained by aerodynamic response measurement value and the docking state type is screened. When the docking state is mechanical jamming, the positioning pin is removed and the hole is cleaned before re-insertion to obtain a re-inserted positioning pin. The insertion force and displacement sequence of the re-inserted positioning pin are sampled and the mechanical insertion work is calculated again. If the connection is still not true when the docking status is sealed and contaminated, after repeated purging and dust removal, or when the docking status is mechanically stuck, after repeated pin removal and hole cleaning, the maximum number of retries is reached, an alarm is triggered on the positioning pin and the connector air path, and the docking result is docking failure.

[0038] Specifically, when the docking status is determined to be true connection, the pin is in place, the air pressure is commensurate with the insertion depth, and the seal is intact. An enable signal is sent to the pneumatic gripper control valve to release the pneumatic gripper to start subsequent gripping, and the docking result is recorded as docking complete. When the docking status is determined to be seal contamination, since the mechanical insertion work is not less than 420 mJ and the pin is indeed in place, there is no need to remove the pin to disturb the mechanical side. The positioning pin insertion state remains unchanged, and 0.6 MPa compressed air is introduced into the purge branch at the joint to purge the joint sealing surface, blowing away the welding slag and dust on the sealing surface to obtain the dust-free joint. Then, the air pressure of the dust-free joint is resampled at the time of pin placement according to millisecond intervals, and a new aerodynamic response measured value is obtained by re-performing the first-order difference and taking the peak value. The new aerodynamic response measured value is then compared with the expected aerodynamic response value to screen the docking status type. Since the mechanical side has not moved, the mechanical insertion work uses the previous value and does not need to be recalculated.

[0039] When the docking status is determined to be mechanical jamming, because the mechanical insertion work has dropped below 420 millijoules and the pin has not sunk into place, the robot's wrist must be driven to lift up to remove the positioning pin from the positioning hole, and the branch of the positioning hole must be vented to remove welding slag and foreign objects from the bottom of the hole. This is called pin removal and hole cleaning. Then, the wrist is driven to press down again to re-insert the pin and obtain the re-inserted positioning pin. Since the pin has gone through the insertion stroke again, the force and displacement are completely updated. The insertion force and displacement of the re-inserted positioning pin must be re-collected from the point where the conical guide section touches the hole opening, the insertion force and displacement sequence must be re-synthesized, and the mechanical insertion work must be recalculated by trapezoidal integration before subsequent comparison. If, after repeated purging and dust removal or repeated pin removal and hole cleaning, the same docking status type fails to achieve a true connection after a cumulative maximum of 3 attempts, the docking action is stopped, an audible and visual alarm is issued to the positioning pin and the joint air path, and the host computer is notified. The docking result is recorded as a docking failure. The maximum of 3 attempts is based on the experience that the amount of slag falling in a single welding operation can usually be cleared by one or two purging or hole cleaning attempts. If it still fails after 3 attempts, it indicates that the slag falling is not accidental and manual intervention is required for troubleshooting.

[0040] The above describes the automatic docking control method for pneumatic joints of robot manipulators in the embodiments of this application. The following describes the automatic docking control system for pneumatic joints of robot manipulators in the embodiments of this application. One embodiment of the automatic docking control system for pneumatic joints of robot manipulators in the embodiments of this application includes: The sampling module is used to continuously sample the insertion force and displacement during the insertion process of the positioning pin to obtain the insertion force-displacement sequence. The integration module is used to integrate the insertion displacement with respect to the insertion force-displacement sequence to obtain the mechanical insertion work; The filtering module is used to substitute the mechanical insertion work into the true connection mapping to obtain the expected value of the aerodynamic response, obtain the measured value of the aerodynamic response from the first-order differential peak value of the joint air pressure, and filter out the docking state type based on the level of the mechanical insertion work and the lower limit of the insertion work, combined with the deviation direction of the measured value of the aerodynamic response relative to the expected value of the aerodynamic response. The docking state type includes mechanical jamming where the mechanical insertion work is lower than the lower limit of the insertion work, sealing contamination where the mechanical insertion work is not lower than the lower limit of the insertion work and the measured value of the aerodynamic response is lower than the expected value of the aerodynamic response, and true connection where the mechanical insertion work is not lower than the lower limit of the insertion work and the deviation between the measured value of the aerodynamic response and the expected value of the aerodynamic response is within the consistency tolerance. The matching module is used to match the corresponding recovery strategy according to the docking status type to obtain the docking result between the positioning pin and the connector air passage.

[0041] This invention also provides an automatic docking control device for pneumatic connectors of a robot arm, which can be a server. The device includes a processor, memory, display screen, input device, network interface, and database connected via a system bus. The processor, designed as a computer, provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database stores the data corresponding to this embodiment. The network interface communicates with external terminals via a network connection. When the computer program is executed by the processor, it implements the above-described method.

[0042] The present invention also provides a computer-readable storage medium, which can be a non-volatile computer-readable storage medium or a volatile computer-readable storage medium, wherein the computer-readable storage medium stores instructions that, when the instructions are executed on a computer, cause the computer to perform the steps of the automatic docking control method for the pneumatic joint of the robot manipulator.

[0043] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0044] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a robot manipulator pneumatic connector automatic docking control device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic docking control method for pneumatic joints of a robot manipulator, characterized in that, The method includes: Step S1: Continuously sample the insertion force and displacement during the insertion process of the positioning pin to obtain the insertion force-displacement sequence; Step S2: Integrate the insertion displacement with respect to the insertion force displacement sequence to obtain the mechanical insertion work; Step S3: Substitute the mechanical insertion work into the true connection mapping to obtain the expected value of the aerodynamic response. Obtain the measured value of the aerodynamic response from the first-order differential peak value of the joint air pressure. Based on the level of the mechanical insertion work and the lower limit of the insertion work, and combined with the deviation direction of the measured value of the aerodynamic response relative to the expected value of the aerodynamic response, filter to obtain the docking state type. The docking state type includes mechanical jamming where the mechanical insertion work is lower than the lower limit of the insertion work, sealing contamination where the mechanical insertion work is not lower than the lower limit of the insertion work and the measured value of the aerodynamic response is lower than the expected value of the aerodynamic response, and true connection where the mechanical insertion work is not lower than the lower limit of the insertion work and the deviation between the measured value of the aerodynamic response and the expected value of the aerodynamic response is within the consistency tolerance. Step S4: Match the corresponding recovery strategy according to the docking status type to obtain the docking result of the positioning pin and the connector air passage.

2. The automatic docking control method for pneumatic joints of robot manipulators according to claim 1, characterized in that, Step S1 includes: From the moment the tapered guide section of the self-positioning pin contacts the opening of the positioning hole, the pin seat force sensor of the self-positioning pin and the displacement sensor at the bottom of the positioning hole are synchronously triggered and sampled according to the set sampling period to obtain the insertion force sampling value and the insertion displacement sampling value with time index. Based on the same time index of the insertion force sampling value and the insertion displacement sampling value, a single pin insertion force displacement sampling point is obtained by pairing and combining them. Based on the positioning displacement threshold and the insertion timeout duration, the sampling cutoff of the single pin insertion force displacement sampling points is determined, and the single pin insertion force displacement sampling points before reaching the positioning displacement threshold or the insertion timeout duration are arranged in time index order to obtain the single pin insertion force displacement subsequence. The single-pin insertion force displacement subsequence of each positioning pin is aggregated by pin to obtain the insertion force displacement sequence.

3. The automatic docking control method for pneumatic joints of robot manipulators according to claim 1, characterized in that, Step S2 includes: Based on the insertion force displacement sequence, the single-pin insertion force displacement subsequence of each positioning pin is obtained by splitting the pin. Based on the insertion displacement difference between two adjacent sampling points in the single pin insertion force displacement subsequence, the single pin insertion force displacement subsequence is divided into adjacent intervals to obtain the single pin insertion interval. The average value of the insertion force at the two sampling points at the beginning and end of the single pin insertion interval is multiplied by the insertion displacement difference of the single pin insertion interval to obtain the single pin interval work increment. The single pin interval work increments of the same positioning pin are accumulated by pin to obtain the single pin mechanical insertion work. The mechanical insertion work of each locating pin is obtained by arithmetically averaging the single pin mechanical insertion work.

4. The automatic docking control method for pneumatic joints of robot manipulators according to claim 1, characterized in that, In step S3, substituting the mechanical plugging work into the true connectivity mapping to obtain the expected aerodynamic response value includes: Based on the mechanical insertion work of multiple dockings under clean working conditions and the peak value of the gas pressure rise rate after the gas path is pressurized after docking, a sample pair of mechanical insertion work and gas pressure rise rate peak value is formed. The sample is subjected to a monotonically increasing linear fitting process on the input least squares to obtain the true connectivity mapping that includes the true connectivity slope and the true connectivity intercept. Substituting the mechanical plugging work into the true connectivity mapping, and then performing a linear conversion by multiplying the mechanical plugging work by the true connectivity slope and adding it to the true connectivity intercept, the expected value of the aerodynamic response is obtained.

5. The automatic docking control method for pneumatic joints of robot manipulators according to claim 1, characterized in that, In step S3, obtaining the measured aerodynamic response value from the first-order differential peak value of the air pressure in the connector air path includes: Starting from the moment when the positioning pin reaches its displacement, the air pressure in the joint air circuit is continuously sampled according to a set sampling period to obtain an air pressure sequence with a time index. A first-order difference processing is performed based on the ratio of the pressure difference between two adjacent sampling points in the pressure sequence to the sampling period to obtain the pressure rise rate sequence. The pressure rise rate sequence is filtered by numerical value to obtain the peak value of the pressure rise rate with the largest value, and the peak value of the pressure rise rate is used as the measured value of the aerodynamic response.

6. The automatic docking control method for pneumatic joints of a robot manipulator according to claim 1, characterized in that, In step S3, the process of selecting the docking state type based on the relative levels of the mechanical insertion work and the lower limit of the insertion work, and considering the deviation direction of the measured aerodynamic response value from the expected aerodynamic response value, includes: The aerodynamic response deviation is obtained by performing deviation calculation based on the difference between the measured aerodynamic response value and the expected aerodynamic response value. The mechanical insertion work is compared with the lower limit of the insertion work, and the aerodynamic response deviation is compared with the consistency tolerance in terms of amplitude to obtain the comparison result. The docking status type is obtained by filtering the comparison results. The docking status type includes: mechanical jamming corresponding to the mechanical insertion work being lower than the lower limit of the insertion work; sealing contamination corresponding to the mechanical insertion work not being lower than the lower limit of the insertion work and the aerodynamic response deviation being negative and exceeding the consistency tolerance; and true connection corresponding to the mechanical insertion work not being lower than the lower limit of the insertion work and the aerodynamic response deviation being within the consistency tolerance.

7. The automatic docking control method for pneumatic joints of a robot manipulator according to claim 1, characterized in that, Step S4 includes: When the docking state type is true connection, the pneumatic gripper control valve is enabled, and the docking result between the positioning pin and the connector air circuit is docking complete. When the docking state type is sealed contamination, the sealing surface of the joint is purged and dusted while keeping the positioning pin insertion state unchanged, to obtain a dust-free joint. The air pressure of the joint air passage of the dust-free joint is then re-obtained using the measured values ​​of the aerodynamic response and the screening of the docking state type. When the docking state is mechanical jamming, the positioning pin is re-inserted after being removed and the hole is cleaned. The insertion force and displacement of the re-inserted positioning pin are then sampled again and the mechanical insertion work is calculated. If the connection is still not true when the docking status is sealed and contaminated, after repeated purging and dust removal, or when the docking status is mechanically stuck, after repeated pin removal and hole cleaning, the maximum number of retries is reached, an alarm is triggered on the positioning pin and the joint air path, and the docking result is docking failure.

8. An automatic docking control system for pneumatic joints of a robot manipulator, characterized in that, For implementing the automatic docking control method for pneumatic joints of a robot manipulator as described in any one of claims 1-7, the automatic docking control system for pneumatic joints of the robot manipulator comprises: The sampling module is used to continuously sample the insertion force and displacement during the insertion process of the positioning pin to obtain the insertion force-displacement sequence. The integration module is used to integrate the insertion displacement with respect to the insertion force-displacement sequence to obtain the mechanical insertion work; The filtering module is used to substitute the mechanical insertion work into the true connection mapping to obtain the expected value of the aerodynamic response, obtain the measured value of the aerodynamic response from the first-order differential peak value of the joint air pressure, and filter out the docking state type based on the level of the mechanical insertion work and the lower limit of the insertion work, combined with the deviation direction of the measured value of the aerodynamic response relative to the expected value of the aerodynamic response. The docking state type includes mechanical jamming where the mechanical insertion work is lower than the lower limit of the insertion work, sealing contamination where the mechanical insertion work is not lower than the lower limit of the insertion work and the measured value of the aerodynamic response is lower than the expected value of the aerodynamic response, and true connection where the mechanical insertion work is not lower than the lower limit of the insertion work and the deviation between the measured value of the aerodynamic response and the expected value of the aerodynamic response is within the consistency tolerance. The matching module is used to match the corresponding recovery strategy according to the docking status type to obtain the docking result between the positioning pin and the connector air passage.

9. An automatic docking control device for pneumatic connectors of a robot manipulator, characterized in that, The method includes a memory and a processor, the memory storing a computer program that can run on the processor, and the processor executing the computer program to implement the automatic docking control method for pneumatic joints of a robot manipulator as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run by the processor, it causes the processor to execute the automatic docking control method for the pneumatic joint of the robot manipulator as described in any one of claims 1 to 7.

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