Locking state verification process of mechanical arm quick-change module

Abstract

The application discloses a kind of mechanical arm quick-change module locking state verification process, comprising: drive servo motor to first speed positive rotation locking mechanism to preset locking position, record instantaneous torque T1;With the second speed lower than first speed reverse rotation preset backoff angle θ1, again with the second speed positive rotation θ1 Angle return, record return moment instantaneous torque T2, wherein θ1 Less than a meshing tooth pitch corresponding motor angle;Control the acceleration pulse of the end of mechanical arm along with the axial direction perpendicular to locking pin, record torque fluctuation peak T3;Calculate ΔT1=T1-T2 and ΔT2=T3-T1;Obtain pre-calibrated static threshold K1 and dynamic threshold K2;If ΔT1≤K1 and ΔT2≤K2 then determine normal locking, otherwise determine false locking.The application utilizes motor torque response itself, without external sensor can identify false locking and evaluate dynamic impact resistance.

Description

Technical Field

[0001] This invention relates to the field of robotic arm assembly technology, and in particular to a locking status verification process for a quick-change module of a robotic arm. Background Technology

[0002] In modern industrial automation, robotic arms, as core execution units, directly determine the flexibility and efficiency of production lines through their ability to rapidly switch end effectors. Quick-change modules are key components for achieving this function, allowing robotic arms to automatically change different actuators within seconds. However, the connection reliability of quick-change modules, especially in high-load, high-dynamic operating environments, is crucial. The stability of their locking state not only affects processing accuracy and equipment lifespan but also directly impacts production safety. Therefore, accurately and reliably detecting whether the quick-change module is in a true locking state, rather than a superficial, false locking, has become a critical technical problem that urgently needs to be solved in this field.

[0003] To address this challenge, existing technologies primarily rely on two types of solutions. One type involves purely mechanical structural design, such as adding multiple redundant locking pins or employing a flexible self-locking structure, attempting to physically prevent loosening. The other type relies on external sensor feedback, such as placing proximity switches, pressure sensors, or optical sensors at the connection interface, determining whether the connection is in place by reading the sensor's switching or analog signals. However, these methods reveal a common drawback in practical applications: insufficient environmental adaptability. In complex working conditions involving vibration, temperature changes, oil contamination, or dust, the mechanical structure may develop clearances due to minor wear, severely reducing the accuracy and stability of external sensors, leading to frequent misjudgments. More critically, most existing technologies only perform a single judgment on the static connection state after locking, failing to capture subtle changes in dynamic resistance during the locking process, and even less able to predict whether the connection will instantly fail under lateral impact. Therefore, a seemingly connected quick-change module may have a locking pin that is not fully engaged due to a slight deviation. This hidden instability is extremely difficult to detect in static testing, but it can suddenly come loose during high-load operation, becoming a major safety hazard. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology in detecting the locking status of the quick-change module of the robotic arm, which relies on external sensors, resulting in poor environmental adaptability, and can only make static judgments and cannot identify false locking status or predict the risk of dynamic loosening. The present invention provides a locking status verification process for the quick-change module of the robotic arm, which can utilize the torque response characteristics of the servo motor itself, and achieve reliable verification that is insensitive to external interference, can quantitatively identify false locking status, and can evaluate dynamic impact resistance by comparing the torque difference after initial locking and micro-motion relocking, as well as the torque fluctuation under lateral impact.

[0005] To address the aforementioned technical problems, this invention provides a locking state verification process for a quick-change module of a robotic arm, applied to a locking mechanism driven by a servo motor, the locking mechanism being installed at the end of the robotic arm, and comprising the following steps: Drive the servo motor to rotate forward at the first speed to drive the locking mechanism to the preset locking position, and record the instantaneous torque value T1 of the motor at the moment the preset locking position is reached; The servo motor is driven to rotate in the opposite direction at a second speed lower than the first speed by a preset retraction angle θ1, and then rotates in the forward direction at the second speed by an angle θ1, so that the locking mechanism returns to the preset locking position, and the instantaneous torque value T2 at the moment of return is recorded; wherein: θ1 is less than the motor angle corresponding to one meshing tooth pitch of the locking mechanism, so that the locking mechanism still maintains the meshing contact state after the reverse micro-motion, and T2 is used to characterize the residual locking stress in the contact state; The robot arm body is controlled to execute a preset short-range high-frequency pulse control command, so that the end of the robot arm generates an acceleration pulse of preset amplitude in a direction perpendicular to the locking pin axis, and the peak torque fluctuation T3 of the servo motor during the acceleration pulse is recorded. Calculate the first torque difference ΔT1 = T1 - T2, and the second torque difference ΔT2 = T3 - T1; Obtain the pre-calibrated static resistance deviation threshold K1 and dynamic impact resistance threshold K2, where K1 and K2 are the standard deviation multiples of ΔT1 and ΔT2 or fixed tolerance limits obtained from historical data statistics under normal locking conditions, respectively. If ΔT1≤K1Δ and ΔT2≤K2, then the locking mechanism is determined to be in a normal locking state. If ΔT1>K1 or ΔT2>K2, the locking mechanism is determined to be in a false locking state.

[0006] In one embodiment of the present invention, the preset backoff angle θ1 is determined as follows: Before driving the servo motor to rotate in the opposite direction at the second speed at the preset retraction angle θ1, drive the servo motor to rotate in the forward direction at a third speed lower than the second speed, and continuously collect the instantaneous torque value of the servo motor. The motor angle position corresponding to the turning point where the torque value changes from a stable state to a continuously increasing state is recorded as the engagement start point. Continue rotating forward until the torque value reaches a stable high value, then record the current motor angle position as the fully engaged position. The total rotation angle from the starting point of engagement to the fully engaged position is recorded as the total engagement stroke, and the preset return angle θ1 is set to 5% to 15% of the total engagement stroke.

[0007] In one embodiment of the present invention, the static resistance deviation threshold K1 is pre-calibrated according to the following steps: With the locking mechanism in a known normal locking state, the following steps are repeated N times: driving the servo motor to rotate forward at a first speed to move the locking mechanism to a preset locking position and recording T1; driving the servo motor to rotate backward at a second speed by θ1 and then rotating forward at the second speed by θ1 to return and recording T2. Each time, a set of T1 is obtained. i and T2 i Calculate ΔT1 each time. i =T1 i -T2 i N ΔT1 values ​​are obtained. i Values, where N≥10; Calculate the N ΔT1 i Given the mean μ1 and standard deviation σ1 of the values, K1 is set as: K1 = μ1 + 3σ1.

[0008] In one embodiment of the present invention, the dynamic impact resistance threshold K2 is pre-calibrated according to the following steps: With the locking mechanism in a known normal locking state, the step of controlling the robotic arm to execute short-range high-frequency pulse control commands to generate acceleration pulses at the end of the robotic arm and recording torque fluctuation peak values ​​T3 is repeated M times, obtaining a set of T1 each time. j and T3 j T1 j For the instantaneous motor torque value recorded when it is initially locked into position during the same calibration process, calculate ΔT2 for each step. j =T3 j -T1 j M ΔT2 values ​​were obtained. j Values, where M≥10; Calculate the M ΔT2 values. j The mean μ2 and standard deviation of the values σ2 K2 is set as: K2 = μ2 + 3σ2.

[0009] In one embodiment of the present invention, the preset short-range high-frequency pulse control command is: to control the robotic arm body to complete a reciprocating jog displacement with an amplitude of 1 mm to 3 mm in a direction perpendicular to the locking pin axis within a time of 0.05 seconds to 0.2 seconds, so that the end of the robotic arm generates an acceleration pulse with a peak acceleration of 0.5g to 2g, where g is the gravitational acceleration.

[0010] In one embodiment of the present invention, the direction of the reciprocating jog displacement is as follows: starting from the preset locking position, first move half the amplitude distance in a single direction perpendicular to the axis of the locking pin, then move the full amplitude distance in the opposite direction, and finally return to the preset locking position.

[0011] In one embodiment of the present invention, recording the instantaneous torque value T1 of the motor at the moment of reaching the preset locking position and the instantaneous torque value T2 at the moment of return specifically includes: acquiring the current loop feedback current value of the motor in real time through the driver of the servo motor at a sampling frequency of not less than 200Hz, converting the current value into an instantaneous torque value according to the torque constant of the servo motor, and reading the instantaneous torque value at the moment when the position sensor signal is detected to be triggered or the encoder reaches the preset pulse count as T1 or T2.

[0012] In one embodiment of the present invention, recording the torque fluctuation peak value T3 of the servo motor during the acceleration pulse action specifically includes: from the moment the short-range high-frequency pulse control command is issued until the command is completed, continuously collecting all instantaneous torque values ​​of the servo motor during this time period, taking the maximum and minimum values, calculating the difference between the maximum and minimum values, and using the difference as the torque fluctuation peak value T3.

[0013] In one embodiment of the present invention, the second speed is 10% to 30% of the first speed, and the value range of the first speed satisfies: 60° / s≤ω1≤180° / s.

[0014] In one embodiment of the present invention, after determining that the locking mechanism is in a false locking state, the following steps are further included: the controller issues an alarm signal, and the historical trend analysis step is further included: storing ΔT1 and ΔT2 calculated in each verification into the historical database, calculating the sliding average value A1 of ΔT1 and the sliding average value A2 of ΔT2 in the most recent L verifications, where L≥5; if the sliding A1 increases monotonically for three consecutive times and the current sliding A1 exceeds 150% of the initial A1, or the sliding A2 increases monotonically for three consecutive times and the current sliding A2 exceeds 130% of the initial A2, then a warning of performance degradation of the locking mechanism is output.

[0015] The technical solution of the present invention has the following advantages compared with the prior art: The locking status verification process for the quick-change module of the robotic arm described in this invention effectively overcomes the limitations of traditional quick-change module locking status detection methods, such as insufficient environmental adaptability and susceptibility to misjudgment under complex working conditions, by introducing dynamic monitoring and multi-dimensional analysis of servo motor torque. The process of this invention can accurately identify false locking states, avoiding the potential risk of loosening due to incomplete engagement of the locking pin, thereby improving the reliability and operational safety of the robotic arm end-effector connection. Attached Figure Description

[0016] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein: Figure 1This is a flowchart of the locking status verification process of the robotic arm quick-change module of the present invention; Figure 2 This is a flowchart of the steps for determining the preset retraction angle θ1 according to the present invention; Figure 3 This is a flowchart of the steps for calibrating the static resistance deviation threshold K1 according to the present invention; Figure 4 This is a flowchart of the steps for calibrating the dynamic impact resistance threshold K2 according to the present invention; Figure 5 This is a flowchart of the steps for historical trend analysis in this invention. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0018] Reference Figure 1 As shown, this invention proposes a locking state verification process based on the self-sensing electrical characteristics of the drive motor. This scheme does not rely on any external additional sensors. By analyzing the torque response characteristics of the servo motor under a specific control sequence, it achieves a quantitative assessment of the locking state. The core of its technical solution lies in utilizing the different resistance characteristics exhibited by the locking mechanism at different engagement depths. Through the design of a four-step verification process of locking-slight loosening-relocking-impact resistance, subtle differences in mechanical state are transformed into measurable differences in motor torque.

[0019] Specifically, the process first performs an initial locking action, driving the servo motor to rotate forward at a first speed and move the locking mechanism to the preset locking position, recording the instantaneous torque T1 of the motor at this moment. T1 reflects the total torque overcoming the contact surface friction and meshing resistance when the initial locking is in place, serving as a benchmark reference value. Subsequently, the process enters a unique reverse micro-motion and forward reset phase: rotating backward at a lower second speed by a small preset retraction angle θ1, and then immediately rotating forward at the same second speed by the same angle back to the locking position, recording the instantaneous torque T2 at the moment of return. Precise control of speed and angle is crucial here—θ1 is strictly limited to a motor angle less than one meshing tooth pitch, ensuring that the locking mechanism remains within the meshing contact area after the reverse micro-motion and is not completely disengaged. This allows T2 to accurately characterize the residual locking stress of the locking mechanism after the micro-motion release. By calculating ΔT1=T1-T2, the process can effectively identify false locking states. In a true locking state, the torque values ​​when reaching the same position twice should be highly consistent, and ΔT1 is very small. However, if the initial locking is false due to misaligned teeth or foreign objects, T1 will be abnormally high. But after slightly loosening and re-locking along the correct path, T2 will be at a normal level. At this time, ΔT1 will increase significantly, thus being reliably detected.

[0020] Building upon this, the solution further incorporates lateral impact resistance verification to simulate the dynamic disturbances that the quick-change module may experience during actual operation. A short-range, high-frequency pulse command is sent to the robotic arm body, causing it to generate an acceleration pulse of a preset amplitude in a direction perpendicular to the locking pin axis. Simultaneously, the peak torque fluctuation T3 of the servo motor under this impact excitation is recorded. The core principle of this step is that a connection in a truly locked state possesses high lateral stiffness, effectively transferring impact energy and resulting in minimal motor torque fluctuation. In contrast, a false locked state has a small gap, which, under lateral impact, generates relative displacement and collision, leading to instantaneous and severe fluctuations in motor torque. By calculating ΔT2 = T3 - T1 and comparing it with a pre-calibrated dynamic impact resistance threshold K2, the locking mechanism's ability to resist lateral dynamic loads can be quantitatively evaluated. Here, thresholds K1 and K2 are not empirical constants but are statistically derived from historical data under normal locking conditions. For example, they can be multiples of the standard deviation of ΔT1 and ΔT2 or fixed tolerance limits, thus giving the judgment adaptive statistical significance.

[0021] In summary, the verification process established in this invention achieves the following beneficial effects: First, it eliminates the reliance on external sensors, allowing the entire detection process to be completed using the servo motor's own driving and sensing capabilities. This reduces system complexity and hardware costs, and improves reliability in harsh environments.

[0022] Secondly, by comparing and analyzing the torques of the initial locking and the micro-locking, it is possible to identify false locking states caused by misalignment, jamming, etc., thus solving the fundamental defect that static detection cannot capture dynamic meshing differences.

[0023] Third, by introducing controllable lateral acceleration pulses and monitoring torque response, a quantitative assessment of dynamic shock resistance is incorporated into the locking verification process for the first time. This allows for early warning of potential loosening of connections that appear normal only in static testing before the equipment is put into high-load operation, thereby improving the overall safety and operational reliability of the robotic arm quick-change module.

[0024] In this embodiment, accurately determining the preset retraction angle θ1 is crucial for ensuring that the locking mechanism maintains engagement after reverse micro-motion and for effectively characterizing the residual locking stress in the contact state. Improper setting of θ1 may lead to distorted measurement results and affect the accuracy of the locking state determination.

[0025] Reference Figure 2As shown, this application further proposes a method for determining the preset retraction angle θ1, specifically including: before driving the servo motor to rotate in the reverse direction at the second speed to the preset retraction angle θ1, driving the servo motor to rotate in the forward direction at a third speed lower than the second speed, and continuously collecting the instantaneous torque value of the servo motor; recording the motor angle position corresponding to the turning point where the torque value changes from a stable state to a continuously rising state as the engagement start point; continuing to rotate in the forward direction until the torque value reaches a stable high value state, recording the current motor angle position as the full engagement position; recording the total rotation angle from the engagement start point to the full engagement position as the total engagement stroke, and setting the preset retraction angle θ1 to 5% to 15% of the total engagement stroke.

[0026] Specifically, when the servo motor is driven to rotate forward at a third speed lower than the second speed, the instantaneous torque value of the servo motor can be continuously collected to monitor the force changes of the locking mechanism during engagement in real time. Using a lower third speed helps to reduce inertial effects and dynamic impacts, making the torque value change more stable and realistic, thereby improving the accuracy of data acquisition.

[0027] The motor angular position corresponding to the turning point where the torque value transitions from a stable state to a continuously increasing state is recorded as the engagement initiation point. This turning point marks the beginning of physical contact and resistance generation among the components of the locking mechanism, representing the initial stage of the locking mechanism entering the engagement process. By accurately identifying this turning point, the precise position at which the locking mechanism begins effective engagement can be determined.

[0028] Continue rotating forward until the torque value reaches a stable high value; the current motor angular position is recorded as the fully engaged position. The stable high value state typically indicates that the engaging teeth or structure of the locking mechanism have fully engaged, but the final locking force has not yet been applied. This position represents the maximum effective engagement depth of the locking mechanism without additional locking force.

[0029] The total rotation angle from the initial engagement point to the fully engaged position is recorded as the total engagement stroke. The total engagement stroke is the motor rotation angle required for the locking mechanism to go from initial contact to full engagement; it reflects the mechanical structural characteristics and engagement depth of the locking mechanism. This parameter is a quantitative representation of the inherent properties of the locking mechanism.

[0030] Finally, the preset retraction angle θ1 is set to 5%–15% of the total engagement stroke. By associating θ1 with the total engagement stroke, the determination of θ1 becomes adaptive, allowing adjustment based on the actual mechanical characteristics of different locking mechanisms. The 5%–15% range is an optimized proportion that ensures the locking mechanism remains engaged during reverse micro-movements, preventing disengagement and thus preventing T2 measurement failure, while also providing sufficient retraction to release some residual stress, allowing T2 to more accurately reflect the residual locking stress in the contact state.

[0031] Through the above technical solution, during the process of driving the servo motor to rotate forward at a third speed lower than the second speed and continuously collecting instantaneous torque values, the engagement start point and full engagement position of the locking mechanism can be accurately identified, thereby calculating the total engagement stroke. Based on this total engagement stroke, the preset retraction angle θ1 is set to a range of 5% to 15%, so that the determination of θ1 no longer depends on empirical presets, but is adaptively adjusted according to the actual mechanical engagement characteristics of the locking mechanism. This ensures that the locking mechanism always maintains a reliable engagement contact state during the reverse micro-motion process, so that the recorded instantaneous torque value T2 can accurately characterize the residual locking stress in the contact state. Therefore, the calculated first torque difference value ΔT1 is more realistic and reliable, significantly improving the accuracy and robustness of the locking state verification, effectively avoiding misjudgments caused by improper θ1 settings, especially providing a more solid data foundation when distinguishing between normal locking and false locking states.

[0032] During the locking status verification process of the robotic arm quick-change module, it is necessary to pre-calibrate the static resistance deviation threshold K1 and the dynamic impact resistance threshold K2 as the basis for judging whether the locking mechanism is in a normal locking state. However, if the setting of these thresholds lacks a scientific and systematic method and relies solely on experience or a few test results, the thresholds may not be accurate enough or robust enough, thus affecting the accuracy and reliability of the locking status judgment. It may even lead to misjudging a normal locking state as a false locking state, or vice versa, posing potential risks to production.

[0033] Reference Figure 3 As shown, this application further proposes a pre-calibration method for the static resistance deviation threshold K1, including the following steps: with the locking mechanism in a known normal locking state, repeatedly execute N steps of driving the servo motor to rotate forward at a first speed to drive the locking mechanism to a preset locking position and recording T1, and driving the servo motor to rotate backward at a second speed by θ1 and then rotating forward at the second speed by θ1 angle back and recording T2, obtaining a set of T1 each time. i and T2 i Calculate ΔT1 each time. i =T 1i -T2 i N ΔT1 values ​​are obtained. i Values, where N≥10; calculate the N ΔT1 values. i Given the mean μ1 and standard deviation σ1 of the values, K1 is set as: K1 = μ1 + 3σ1.

[0034] Specifically, ensuring the locking mechanism is in a known, normal locking state is fundamental to guaranteeing the validity of subsequent data collection. This known, normal locking state typically refers to a condition confirmed by manual inspection and professional equipment testing, after the robotic arm's quick-change module is initially installed, undergoes rigorous debugging or regular maintenance, and the locking mechanism is confirmed to be functionally intact and free from abnormal wear or loosening. Data collected under this condition accurately reflects the locking mechanism's performance under ideal operating conditions, providing a reliable benchmark for subsequent threshold setting.

[0035] Repeat the following steps N times: drive the servo motor to rotate forward at a first speed to move the locking mechanism to a preset locking position and record T1; drive the servo motor to rotate backward at a second speed θ1 and then rotate forward at the second speed by θ1 angle to return and record T2. Each time, a set of T1 is obtained. i and T2 i Calculate ΔT1 each time. i =T1 i -T2 i N ΔT1 values ​​are obtained. i The value is N ≥ 10. Repeating the operation N times aims to obtain a sufficient amount of sample data to eliminate potential random errors from single measurements and internal system fluctuations. Setting N ≥ 10 ensures a sufficient sample size for statistical analysis, making the calculated mean and standard deviation more representative. Each execution of this process yields a set of instantaneous torque values ​​T1. i and T2 i T1 i T2 is the instantaneous torque value when the i-th locking position is reached. i It is the instantaneous torque value when the i-th micro-motion retraction returns to its original position. This is calculated using ΔT1. i =T1 i -T2 i This allows us to obtain the static resistance deviation of the locking mechanism during each operation. These deviation values ​​reflect the inherent variability of the locking mechanism under normal operating conditions.

[0036] Calculate the N ΔT1 i The values ​​are calculated using the mean μ1 and standard deviation σ1. The mean μ1 represents the central tendency or expected value of the static resistance deviation under normal locking conditions. The standard deviation σ1 quantifies the dispersion or range of these deviation values ​​around the mean. These two statistics provide a comprehensive understanding of the distribution characteristics of the static resistance deviation under normal locking conditions.

[0037] K1 is set as: K1 = μ1 + 3σ1. This setting method is based on the "3σ principle" in statistical process control. Under the assumption of normal distribution, approximately 99.73% of the data points will fall within the range of the mean plus or minus three standard deviations. Therefore, setting K1 as μ1 + 3σ1 means setting the upper limit of the static resistance deviation under normal locking conditions on a very strict statistical boundary. Any ΔT1 value exceeding this boundary will be considered an anomaly, thus effectively identifying potential false locking states. This statistically based method ensures that the setting of K1 is both scientifically grounded and fully considers the random fluctuations of the system itself, improving the robustness of the threshold and the accuracy of the judgment.

[0038] Reference Figure 4 As shown, this application further proposes a pre-calibration method for the dynamic impact resistance threshold K2, specifically including the following steps: with the locking mechanism in a known normal locking state, repeatedly execute the step of controlling the robotic arm body to execute short-range high-frequency pulse control commands to generate acceleration pulses at the end of the robotic arm and record the torque fluctuation peak value T3 M times, obtaining a set of T1 each time. j and T3 j T1 j For the instantaneous motor torque value recorded when it is initially locked into position during the same calibration process, calculate ΔT2 for each step. j =T3 j -T1 j M ΔT2 values ​​were obtained. j Values, where M ≥ 10; calculate the M ΔT2 values. j Given the mean μ2 and standard deviation σ2 of the values, K2 is set as: K2 = μ2 + 3σ2.

[0039] Specifically, the premise that the locking mechanism is in a known normal locking state is consistent with the calibration logic of the static resistance deviation threshold K1. A known normal locking state refers to a condition where, after rigorous debugging, initial installation, or regular maintenance of the robotic arm quick-change module, the locking mechanism is confirmed to be functionally sound and free from abnormal wear or loosening through manual inspection and professional equipment testing. Data collected under this state can accurately reflect the dynamic response characteristics of the locking mechanism under lateral impact conditions under ideal working conditions, providing a reliable benchmark for setting the dynamic impact resistance threshold K2.

[0040] Repeat the steps described above M times, which involve controlling the robotic arm to execute short-range high-frequency pulse control commands to generate acceleration pulses at the end of the robotic arm and recording the torque fluctuation peak value T3, to obtain a set of T1 values ​​each time. j and T3 jWhere M ≥ 10. Repeating the operation M times aims to obtain sufficient sample data to eliminate the random errors that may exist in a single impact measurement and the influence of random fluctuations in the robot arm's posture and working conditions on the torque response. Setting M ≥ 10 ensures a sufficient sample size for statistical analysis, making the calculated mean and standard deviation statistically significant. Each time this process is executed, the instantaneous motor torque value T1 at the initial locking position must be recorded in the same calibration cycle. j Subsequently, a short-range high-frequency pulse control command is executed, causing the end effector of the robotic arm to generate an acceleration pulse of a preset amplitude in a direction perpendicular to the axis of the locking pin, and the peak torque fluctuation T3 of the servo motor during this impact is recorded. j By calculating ΔT2 j =T3 j -T1 j This allows us to obtain the net increment of the dynamic response in each impact test. This net increment reflects the additional fluctuation of the motor torque when the locking mechanism resists lateral impact under normal locking conditions, eliminating the baseline difference of the static locking torque itself.

[0041] Calculate the M ΔT2 values. j The values ​​are calculated using the mean μ² and standard deviation σ². The mean μ² represents the central tendency or expected value of the net increment of the dynamic shock resistance response under normal locking conditions. The standard deviation σ² quantifies the dispersion or fluctuation range of these net increment values ​​around the mean, reflecting the stability of the dynamic response of the locking mechanism under repeated impacts. These two statistics provide a comprehensive understanding of the distribution characteristics of the dynamic shock resistance response under normal locking conditions.

[0042] K2 is set as: K2 = μ2 + 3σ2. Consistent with the method used to set the static threshold K1, the "3σ principle" from statistical process control is also adopted here. Under the assumption of a normal distribution, approximately 99.73% of the data points will fall within the range of the mean plus or minus three standard deviations. Therefore, setting K2 as μ2 + 3σ2 means setting the upper limit of the dynamic shock resistance response under normal locking conditions on a strict statistical boundary. Any ΔT2 value exceeding this boundary indicates that the locking mechanism has generated torque fluctuations beyond the normal range when subjected to lateral impact, meaning that the locking mechanism may have minor gaps or insufficient engagement, exhibiting abnormal response characteristics under dynamic loads. This setting gives K2 a scientific statistical basis, enabling it to adaptively reflect the inherent dynamic fluctuation range of different robotic arm quick-change modules under normal conditions, thereby accurately identifying false locking states with a risk of loosening in subsequent actual testing.

[0043] In some embodiments described above in this application, an acceleration pulse is generated by controlling the robotic arm to execute a short-range high-frequency pulsation control command to record the peak torque fluctuation T3 of the servo motor, thereby evaluating the dynamic shock resistance of the locking mechanism. However, if the parameters of the pulsation control command are not set properly, the generated acceleration pulse may be insufficient to effectively excite the potential dynamic defects of the locking mechanism, or the pulse may be too strong and cause unnecessary impact on the robotic arm or locking mechanism, affecting the accuracy and safety of the verification.

[0044] In response, this application further proposes a specific implementation method for a preset short-range high-frequency pulse control command, namely, controlling the robotic arm body to complete a reciprocating jog displacement with an amplitude of 1 mm to 3 mm in a direction perpendicular to the locking pin axis within a time of 0.05 seconds to 0.2 seconds, so that the end of the robotic arm generates an acceleration pulse with a peak acceleration of 0.5g to 2g, where g is the gravitational acceleration.

[0045] Specifically, the preset short-range high-frequency pulse control commands refer to a series of motion commands pre-programmed onto the robotic arm body. These commands aim to induce the locking mechanism to withstand a controlled, transient dynamic load. "Short-range" means limited displacement, and "high-frequency" refers to high motion speed; both work together to produce an impact effect rather than a continuous load. These commands are crucial for simulating external disturbances or impacts that the locking module may encounter during actual operation, revealing any dynamic instability or false locking conditions that might be missed by static inspections. These commands can be implemented through the robotic arm's controller, which converts the commands into motion trajectories for the motors of each joint of the robotic arm.

[0046] The control of the robotic arm body completes displacement within a time frame of 0.05 to 0.2 seconds, limiting the execution duration of the pulse control command. Setting the time range between 0.05 and 0.2 seconds ensures the instantaneous and high-frequency characteristics of the pulse behavior, helping to concentrate energy in a short time and generate an effective impact effect. If the execution time is too long, it may evolve into continuous vibration rather than an instantaneous pulse, failing to effectively simulate impact loads; if the time is too short, it may place excessively high demands on the response speed of the control system, making it difficult to achieve accurately. This time window setting aims to balance the impact effect with system controllability, ensuring that while effectively stimulating the dynamic response of the locking mechanism, excessive stress on the robotic arm body is avoided.

[0047] The direction of the reciprocating jog displacement is defined as perpendicular to the axial direction of the locking pin. This is based on an in-depth analysis of the failure modes of the locking mechanism. The locking pin typically provides the main locking force along its axial direction, while when external impacts or vibrations cause a false locking state, it often manifests as a relative displacement or loosening perpendicular to the axial direction of the locking pin. Therefore, applying pulsating displacement in this direction can more effectively simulate the impact load in actual operation and stimulate the dynamic response of the locking mechanism in this direction. The amplitude setting of 1 mm to 3 mm ensures that the displacement is small enough to prevent the locking mechanism from completely disengaging during the calibration process, while being large enough to produce a detectable dynamic response. This small but rapid displacement can effectively detect the stability of the locking mechanism under dynamic loads without causing it to completely unlock or be damaged.

[0048] Ultimately, through the aforementioned control, an acceleration pulse with a peak acceleration ranging from 0.5g to 2g is generated at the end of the robotic arm, where g is the acceleration due to gravity. This peak acceleration range represents the dynamic impact intensity applied to the locking mechanism. This range is set based on considerations of the impact loads that may be encountered in real-world applications, as well as an assessment of the dynamic response sensitivity of the locking mechanism. Acceleration below 0.5g may be insufficient to reveal potential false locking problems, while acceleration above 2g may be too severe, causing unnecessary wear or damage to the robotic arm and locking mechanism. By precisely controlling the peak value of the acceleration pulse, the calibration process can be ensured to be both effective and safe, reliably detecting the stability of the locking mechanism under dynamic conditions.

[0049] In practical operation, accurately controlling the generation of effective and repeatable acceleration pulses at the end effector of the robotic arm to ensure sufficient excitation of the locking mechanism while avoiding unnecessary shaking or energy loss is a key issue affecting the accuracy and stability of the verification. If the direction and sequence of the pulsating displacement are unclear, the generation of acceleration pulses may be unstable, thus affecting the accurate acquisition of the torque fluctuation peak T3, and consequently reducing the reliability of the locking state verification.

[0050] In this regard, this application further proposes that the direction of the reciprocating jog displacement is as follows: starting from the preset locking position, first move half the amplitude distance in a single direction perpendicular to the axis of the locking pin, then move the full amplitude distance in the opposite direction, and finally return to the preset locking position.

[0051] Specifically, in this scheme, the starting point of the reciprocating jog displacement is set to a preset locking position. This means that before the robotic arm's end effector performs the jog displacement, it is first in the preset locking position reached by the locking mechanism. This setting ensures that the initial state of the jog displacement is clear and stable, providing a benchmark for subsequent precise motion control.

[0052] Subsequently, the end effector of the robotic arm moves half the amplitude distance in a single direction perpendicular to the axis of the locking pin. This unidirectional initial displacement is designed to apply a preliminary, directional excitation to the locking mechanism, causing it to undergo slight deformation or force in a specific direction, preparing it for subsequent impact. This setting of "half the amplitude distance" provides sufficient initial excitation while avoiding system instability that might result from excessive initial displacement.

[0053] Immediately afterward, the robotic arm's end effector moves the full amplitude distance in the opposite direction. After completing the initial unidirectional displacement, the end effector immediately moves in the opposite direction, covering the preset full amplitude distance. This step is crucial for generating the acceleration pulse; by rapidly reversing the movement and crossing the initial position, an impact force is effectively generated on the locking mechanism, causing significant torque fluctuations. The full amplitude distance ensures the strength and effectiveness of the impact.

[0054] Finally, the robotic arm's end effector returns to the preset locking position. After completing the full amplitude distance movement in the reverse direction, the end effector precisely returns to the initial preset locking position. This return operation ensures that the robotic arm system returns to its original state after calibration, avoiding end effector position deviations caused by calibration actions, thereby guaranteeing the accuracy and safety of subsequent operations.

[0055] In the locking state verification process of the robotic arm quick-change module, it is necessary to accurately record the instantaneous torque value T1 of the motor at the moment of reaching the preset locking position, the instantaneous torque value T2 at the moment of return, and the peak torque fluctuation T3 of the servo motor during the acceleration pulse.

[0056] In this embodiment, a specific method is further proposed for recording the instantaneous torque value T1 of the motor at the moment of reaching the preset locking position and the instantaneous torque value T2 at the moment of return. The method includes: acquiring the current value of the motor current loop feedback in real time through the driver of the servo motor at a sampling frequency of not less than 200Hz, converting the current value into an instantaneous torque value according to the torque constant of the servo motor, and reading the instantaneous torque value at the moment when the position sensor signal is detected to be triggered or the encoder reaches the preset pulse count as T1 or T2.

[0057] Specifically, the servo motor driver, as the core component of motor control, can monitor and provide feedback on the operating status of the motor's internal current loop in real time. There is a direct linear relationship between the feedback current value of the current loop and the electromagnetic torque generated by the motor. Therefore, directly obtaining this current value through the driver is an efficient and accurate way to indirectly characterize the instantaneous torque of the motor. Using a sampling frequency of no less than 200Hz means that the system performs at least 200 data acquisitions per second. This is crucial for capturing the dynamic response of the motor during rapid movement or changes in force, effectively avoiding signal distortion or the omission of critical instantaneous torque values ​​due to insufficient sampling frequency, thus laying the foundation for subsequent accurate calculations.

[0058] The torque constant of a servo motor is an inherent physical parameter determined by the motor's design and manufacturing. It defines the proportional relationship between the motor's output torque and the current flowing through its windings. By multiplying the real-time acquired current loop feedback current value by this torque constant, the electrical signal can be accurately converted into a physically meaningful instantaneous torque value. This conversion method is a widely adopted standard technique in the field of industrial automation, ensuring the accuracy and reliability of the acquired torque data and providing a solid data foundation for subsequent torque analysis and status judgment.

[0059] To ensure that the recorded instantaneous torque values ​​T1 and T2 accurately correspond to the actual force state of the locking mechanism at a specific mechanical position (i.e., the preset locking position and the return time), this application employs a precise triggering mechanism based on position feedback. A position sensor (e.g., a photoelectric switch, proximity switch, limit switch, etc.) emits a specific electrical signal when the locking mechanism reaches the preset mechanical position, or the encoder built into the servo motor provides precise position information when the motor rotates to the corresponding preset mechanical position and counts the pulses. Upon receiving these precise position trigger signals, the system immediately reads the instantaneous torque value calculated for the current moment. This reading method, synchronized with the precise position, effectively eliminates the influence of time delay or position deviation on the accuracy of torque measurement, ensuring that T1 and T2 are the true instantaneous torques when the locking mechanism is in a critical mechanical state, thus providing high-precision input for subsequent torque difference calculations.

[0060] In this embodiment, a method is proposed to record the torque fluctuation peak T3 of the servo motor during the acceleration pulse. Specifically, this includes: continuously collecting all instantaneous torque values ​​of the servo motor during the short-range high-frequency pulse control command from the moment the command is issued until the command is completed, taking the maximum and minimum values, calculating the difference between the maximum and minimum values, and using the difference as the torque fluctuation peak T3.

[0061] Specifically, to accurately capture the dynamic torque response during acceleration pulses, this application proposes continuously acquiring all instantaneous torque values ​​of the servo motor from the moment the short-range high-frequency pulsating control command is issued until the command is completed. This means that the torque data of the servo motor is continuously acquired throughout the entire duration of the acceleration pulse generated at the end of the robotic arm. This continuous acquisition can be achieved through the current loop feedback function built into the servo driver. The driver monitors and outputs the motor's current value in real time at a high sampling frequency (e.g., hundreds of hertz or even higher), and then converts it into an instantaneous torque value based on the motor's torque constant. By ensuring that data acquisition covers the entire dynamic process, critical torque peaks or valleys can be avoided due to excessively large sampling intervals or improper selection of sampling points.

[0062] After acquiring all instantaneous torque values ​​during the acceleration pulse, the maximum and minimum values ​​need to be identified from these continuously acquired data. This step aims to determine the upper and lower limits of torque fluctuations experienced by the servo motor during dynamic impact. For example, this can be done by iterating through all acquired instantaneous torque data points, comparing and recording the highest and lowest values. These extreme values ​​represent the maximum deviation of the locking mechanism's internal force state in the positive and negative directions when subjected to external impact.

[0063] Subsequently, the difference between the determined maximum and minimum instantaneous torque values ​​is calculated. This difference, the absolute difference between the maximum and minimum values, is defined as the torque fluctuation peak value T3. The T3 value directly reflects the dynamic stress fluctuation amplitude experienced by the locking mechanism under acceleration pulses. Calculating T3 in this way allows for a more comprehensive and accurate quantification of the locking mechanism's dynamic response because it considers the entire fluctuation range, not just the value at a single instant. This T3 value will be used as the basis for subsequent comparison with the dynamic impact resistance threshold K2 to determine whether the locking mechanism is in a normal locking state.

[0064] In some embodiments described above in this application, a method is proposed to verify the state of the locking mechanism by driving a servo motor to rotate forward and backward at different speeds, combined with the pulsation control of the robotic arm body. However, in practical applications, if the drive speed of the servo motor is not properly selected, it may lead to a decrease in torque measurement accuracy, or even cause impact or wear on the mechanism, thereby affecting the accuracy and reliability of the locking state verification.

[0065] In this regard, this application further proposes that the second speed is 10% to 30% of the first speed, and the value range of the first speed satisfies: 60° / s≤ω1≤180° / s.

[0066] Specifically, during the calibration of the locking mechanism, the first speed is used to drive the servo motor to rotate forward, moving the locking mechanism to a preset locking position to achieve the initial locking action and record the instantaneous torque value T1. The second speed is used for subsequent reverse rotation by a preset retraction angle θ1 and then forward rotation by an angle θ1 at the second speed to obtain the instantaneous torque value T2 characterizing the residual locking stress in the contact state. Setting the second speed to a range of 10% to 30% of the first speed aims to ensure that the locking mechanism can operate at a sufficiently low and smooth speed during micro-motion operations, thereby avoiding impacts or vibrations caused by excessive speed, which could affect the accuracy of torque measurement. Simultaneously, this ratio also ensures the efficiency of micro-motion operations, preventing them from being too slow and prolonging the calibration time. For example, the command value of the second speed can be proportionally correlated with the command value of the first speed through servo driver parameter settings, or the second speed can be dynamically calculated in the control algorithm.

[0067] The first speed ω1 is the forward rotation speed of the servo motor during the initial locking process. Limiting the first speed to between 60° / s and 180° / s ensures the locking mechanism reaches its position quickly while maintaining the stability of torque measurement and the safety of the mechanism. If the first speed is too low, the locking process will take longer, affecting verification efficiency; if the first speed is too high, the locking mechanism may experience a large impact when reaching the preset locking position, making the measurement of the instantaneous torque value T1 unstable and potentially causing unnecessary wear on the mechanism. Within this speed range, the servo motor can drive the locking mechanism in a relatively smooth and controlled manner, ensuring accurate acquisition of the T1 value and effectively reducing the impact risk during the locking process. For example, a speed command can be sent to the servo driver via a host computer or PLC, ensuring that the command value falls within the preset range.

[0068] Reference Figure 5 As shown, this application further proposes the steps of issuing an alarm signal and performing historical trend analysis after determining that the locking mechanism is in a false locking state. Specifically, issuing an alarm signal means that when the system detects that the locking mechanism is in a false locking state, it immediately alerts the operator or relevant systems through audible and visual indicators, screen display, or by sending communication commands to the upper-level control system, so as to prompt necessary intervention measures to be taken.

[0069] The historical trend analysis step aims to identify potential changes in the performance of the locking mechanism through monitoring and analysis of long-term data. Specifically, this step involves storing the ΔT1 and ΔT2 calculated for each verification into a historical database. The historical database can be a Structured Query Language (SQL) database, an unstructured database (NoSQL), or a simple log file system, used to persistently store the ΔT1 and ΔT2 values ​​for each verification, usually with timestamp information for subsequent time series analysis.

[0070] Based on this, the system will calculate the moving average A1 of ΔT1 and the moving average A2 of ΔT2 over the most recent L verifications, where L is not less than 5. The moving average is a commonly used time series smoothing technique. By calculating the average value of data within a fixed window, it can effectively filter out short-term fluctuations and reveal the long-term trend of data changes. For example, when L=5, after each new verification result, the system will calculate the average of the most recent 5 ΔT1 values ​​as A1 and the average of the most recent 5 ΔT2 values ​​as A2.

[0071] Furthermore, the system determines whether the locking mechanism's performance is deteriorating based on the trend and magnitude of the sliding average. Specifically, the judgment criteria are as follows: if A1 slides monotonically for three consecutive times and the current A1 slide exceeds 150% of the initial A1, or if A2 slides monotonically for three consecutive times and the current A2 slide exceeds 130% of the initial A2, a performance degradation warning for the locking mechanism is output. Here, "initial A1" and "initial A2" refer to the baseline sliding average values ​​of ΔT1 and ΔT2 obtained through multiple verifications when the locking mechanism is in a brand-new or normal operating state. The condition of three consecutive monotonically increasing values ​​ensures the continuity of the trend, rather than random fluctuations; while the condition of exceeding the initial value by a certain percentage quantifies the degree of degradation, avoiding misjudgments of minor fluctuations. The output method of the performance degradation warning can be similar to that of an alarm signal, but it is usually presented in a more explicit warning or maintenance suggestion form, such as displaying a suggestion to check the locking mechanism on the human-machine interface or notifying maintenance personnel via email / SMS.

[0072] Through the above technical solution, this application introduces long-term trend analysis of the locking mechanism's performance, building upon traditional false locking condition determination. By continuously recording and analyzing historical data of ΔT1 and ΔT2, and calculating their sliding average, the system can effectively identify signs of performance degradation in the locking mechanism, such as progressive wear, loosening, or fatigue, that may occur during operation. When these signs of degradation reach preset trend and magnitude conditions, such as a three-time consecutive monotonically increasing sliding average that significantly exceeds the initial baseline value, the system can issue a timely performance degradation warning. This allows maintenance personnel to intervene in advance for inspection, maintenance, or replacement before the locking mechanism completely fails or causes false locking, thus transforming passive, reactive maintenance based on single-test verification into proactive preventative maintenance. This warning mechanism significantly improves the operational reliability and safety of the robotic arm quick-change module, effectively avoiding downtime losses and potential safety risks caused by sudden failures, extending the equipment's service life, and optimizing maintenance strategies.

[0073] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A locking state verification process for a quick-change module of a robotic arm, applied to a locking mechanism driven by a servo motor, the locking mechanism being installed at the end of the robotic arm, characterized in that, Includes the following steps: Drive the servo motor to rotate forward at the first speed to drive the locking mechanism to the preset locking position, and record the instantaneous torque value T1 of the motor at the moment the preset locking position is reached; The servo motor is driven to rotate in the opposite direction at a second speed lower than the first speed by a preset retraction angle θ1, and then rotates in the forward direction at the second speed by an angle θ1, so that the locking mechanism returns to the preset locking position, and the instantaneous torque value T2 at the moment of return is recorded; wherein: θ1 is less than the motor angle corresponding to one meshing tooth pitch of the locking mechanism, so that the locking mechanism still maintains the meshing contact state after the reverse micro-motion, and T2 is used to characterize the residual locking stress in the contact state; The robot arm body is controlled to execute a preset short-range high-frequency pulse control command, so that the end of the robot arm generates an acceleration pulse of preset amplitude in a direction perpendicular to the locking pin axis, and the peak torque fluctuation T3 of the servo motor during the acceleration pulse is recorded. Calculate the first torque difference ΔT1 = T1 - T2, and the second torque difference ΔT2 = T3 - T1; Obtain the pre-calibrated static resistance deviation threshold K1 and dynamic impact resistance threshold K2, where K1 and K2 are the standard deviation multiples of ΔT1 and ΔT2 or fixed tolerance limits obtained from historical data statistics under normal locking conditions, respectively. If ΔT1≤K1Δ and ΔT2≤K2, then the locking mechanism is determined to be in a normal locking state. If ΔT1>K1 or ΔT2>K2, the locking mechanism is determined to be in a false locking state.

2. The locking state verification process of the robotic arm quick-change module according to claim 1, characterized in that: The preset backoff angle θ1 is determined as follows: Before driving the servo motor to rotate in the opposite direction at the second speed at the preset retraction angle θ1, drive the servo motor to rotate in the forward direction at a third speed lower than the second speed, and continuously collect the instantaneous torque value of the servo motor. The motor angle position corresponding to the turning point where the torque value changes from a stable state to a continuously increasing state is recorded as the engagement start point. Continue rotating forward until the torque value reaches a stable high value, then record the current motor angle position as the fully engaged position. The total rotation angle from the starting point of engagement to the fully engaged position is recorded as the total engagement stroke, and the preset return angle θ1 is set to 5% to 15% of the total engagement stroke.

3. The locking state verification process for the quick-change module of the robotic arm according to claim 1, characterized in that: The static resistance deviation threshold K1 is pre-calibrated according to the following steps: With the locking mechanism in a known normal locking state, the following steps are repeated N times: driving the servo motor to rotate forward at a first speed to move the locking mechanism to a preset locking position and recording T1; driving the servo motor to rotate backward at a second speed by θ1 and then rotating forward at the second speed by θ1 to return and recording T2. Each time, a set of T1 is obtained. i and T2 i Calculate ΔT1 each time. i =T1 i -T2 i N ΔT1 values ​​are obtained. i Values, where N≥10; Calculate the average value μ1 and standard deviation σ1 of the N ΔT1i values, and set K1 as: K1=μ1+3σ1.

4. The locking state verification process of the robotic arm quick-change module according to claim 1, characterized in that: The dynamic impact resistance threshold K2 is pre-calibrated according to the following steps: With the locking mechanism in a known normal locking state, the step of controlling the robotic arm to execute short-range high-frequency pulse control commands to generate acceleration pulses at the end of the robotic arm and recording torque fluctuation peak values ​​T3 is repeated M times, obtaining a set of T1 each time. j and T3 j T1 j For the instantaneous motor torque value recorded when it is initially locked into position during the same calibration process, calculate ΔT2 for each step. j =T3 j -T1 j M ΔT2 values ​​were obtained. j Values, where M≥10; Calculate the M ΔT2 values. j Given the mean μ2 and standard deviation σ2 of the values, K2 is set as: K2 = μ2 + 3σ2.

5. The locking state verification process of the robotic arm quick-change module according to claim 1, characterized in that: The preset short-range high-frequency pulse control command is: control the robotic arm body to complete a reciprocating jog displacement with an amplitude of 1 mm to 3 mm in a direction perpendicular to the locking pin axis within a time of 0.05 seconds to 0.2 seconds, so that the end of the robotic arm generates an acceleration pulse with a peak acceleration of 0.5g to 2g, where g is the acceleration due to gravity.

6. The locking state verification process of the robotic arm quick-change module according to claim 5, characterized in that: The direction of the reciprocating jog displacement is as follows: starting from the preset locking position, it first moves half the amplitude distance in a single direction perpendicular to the axis of the locking pin, then moves the full amplitude distance in the opposite direction, and finally returns to the preset locking position.

7. The locking state verification process for the quick-change module of the robotic arm according to claim 1, characterized in that: The instantaneous torque value T1 of the motor at the moment of reaching the preset locking position and the instantaneous torque value T2 at the moment of return are recorded. Specifically, this includes: acquiring the current value of the motor current loop feedback in real time through the servo motor driver at a sampling frequency of not less than 200Hz, converting the current value into an instantaneous torque value according to the torque constant of the servo motor, and reading the instantaneous torque value at the moment when the position sensor signal is detected to trigger or the encoder reaches the preset pulse count as T1 or T2.

8. The locking state verification process of the robotic arm quick-change module according to claim 1, characterized in that: Record the peak torque fluctuation T3 of the servo motor during the acceleration pulse. Specifically, from the moment the short-range high-frequency pulse control command is issued until the command is completed, continuously collect all instantaneous torque values ​​of the servo motor during this time period, take the maximum and minimum values, calculate the difference between the maximum and minimum values, and use the difference as the peak torque fluctuation T3.

9. The locking state verification process of the robotic arm quick-change module according to claim 1, characterized in that: The second speed is 10% to 30% of the first speed, and the range of the first speed satisfies: 60° / s≤ω1≤180° / s.

10. The locking state verification process of the robotic arm quick-change module according to claim 1, characterized in that: After determining that the locking mechanism is in a false locking state, the following steps are also included: the controller issues an alarm signal, and the historical trend analysis step is also included: ΔT1 and ΔT2 calculated in each verification are stored in the historical database, and the sliding average value A1 of ΔT1 and the sliding average value A2 of ΔT2 in the most recent L verifications are calculated respectively, where L≥5; if the sliding A1 increases monotonically for three consecutive times and the current sliding A1 exceeds 150% of the initial A1, or the sliding A2 increases monotonically for three consecutive times and the current sliding A2 exceeds 130% of the initial A2, then a warning of performance degradation of the locking mechanism is output.

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