Evaluation method for analyzing stability of trigger signal at tail end of robot

Abstract

The invention discloses an evaluation method for analyzing the stability of a trigger signal at the tail end of a robot, and the method comprises the steps: controlling a camera to shoot an image containing the information of a coding point through an external trigger signal, extracting the position information of the coding point in the image, and analyzing the offset, thereby evaluating the stability of the trigger signal. The method comprises the following specific steps: sending a trigger signal through an IO module of a robot controller, and controlling a camera to collect an image; coordinates of coding points in a camera coordinate system are obtained through an image processing technology, and changes of offset are counted based on multiple times of sampling. In the evaluation process, the maximum offset threshold value of the coding point is set to be 10 mm, and if the maximum offset threshold value exceeds the range, the signal is judged to be unstable. Signal jitter evaluation adopts statistical indexes such as a mean value, a standard deviation, a range and a percentile for analysis. According to the method, through multiple acquisition and statistical analysis, the signal transmission stability of the system can be accurately evaluated in complex environments such as network fluctuation, mechanical jitter and system errors.

Description

Technical Field

[0001] The present invention relates to the technical field of robot automation control, and in particular to an evaluation method for analyzing the stability of a robot terminal trigger signal. Background Art

[0002] In robot automation operations, such as gluing and welding, accurate signal transmission and synchronous control are crucial to ensure the quality of the operation. Usually, industrial robots send trigger signals through external control systems to control the cameras or sensors installed at the end to collect data. However, the signal transmission process is affected by various external factors such as network delays, mechanical jitters, and ambient temperature changes, resulting in unstable triggering of cameras or sensors. If the trigger signal is unstable, data collection may be out of sync, affecting the accuracy of the test results. For example, during the gluing process, signal jitter may cause the camera shooting to be inconsistent with the actual gluing position, making it impossible to accurately judge the quality of the glue strip; during the welding process, signal delays may cause inaccurate detection of key welding nodes, affecting welding strength and consistency.

[0003] In the existing technology, most of the focus is on the optimization of camera response speed and system hardware performance, but there is a lack of effective evaluation methods for the stability of the entire signal transmission process. Especially in complex environments, existing evaluation methods often fail to fully consider the impact of external factors on signal jitter. Therefore, there is an urgent need for a method that can systematically evaluate the stability of signal triggering in robot operations, and can comprehensively evaluate the impact of the external environment on signal transmission stability in industrial scenarios such as gluing and welding. Summary of the invention

[0004] The present invention aims to provide an evaluation method for analyzing the stability of a trigger signal at the end of a robot, which is particularly suitable for camera or sensor trigger evaluation in industrial scenarios such as gluing and welding.

[0005] The present invention is achieved in that:

[0006] A method for evaluating the stability of a robot end trigger signal is provided. The specific steps of the method are as follows:

[0007] S100, installing a camera at the end of the robot, wherein the camera works through an external trigger signal, the trigger signal is sent by an IO module of the robot controller, and triggers the camera to acquire an image;

[0008] S200, the image captured by the camera contains information of coded points marked, where the coded points are used to evaluate signal stability;

[0009] S300, when the robot is controlled by program instructions to move to a photographing position at a stable speed, a trigger signal is sent and an image is collected;

[0010] S400, collecting images containing coding point information, extracting the position coordinates of the coding points in the camera coordinate system through image processing, using multiple sampling methods to obtain multiple groups of data and perform signal jitter analysis.

[0011] Preferably, the signal jitter in step S400 is evaluated by analyzing the code point offsets collected multiple times, which specifically includes the following steps:

[0012] S410, collecting a first image containing coded point information, and extracting coordinate information of the coded point in the camera coordinate system as a standard position coordinate value;

[0013] S420, collecting subsequent images, and extracting the relative position coordinate values ​​of the coding points in each image;

[0014] S430, counting the offsets of the relative position coordinate values ​​of the encoding points of the subsequent n-1 images and the standard position coordinate values ​​in the x and y directions;

[0015] S440, using the offset in combination with the movement speed of the manipulator to convert into a signal jitter time, or directly evaluating the stability of the signal based on the offset.

[0016] Preferably, the camera control mainboard receives the trigger signal and controls the camera shooting, and the trigger signal transmission and the camera shooting action are treated as a whole, and the system stability evaluation ignores the time consuming from the camera receiving the signal to executing the shooting, because the time consuming is in microseconds.

[0017] Preferably, a signal stability evaluation process is also included, and the specific steps are:

[0018] S500, extracting the position information of the coding point by image processing technology, and converting it into coordinate values ​​in the camera coordinate system;

[0019] S600, taking the coding point position of the first image as a standard and the coding point positions in other images as relative coordinate values;

[0020] S700, calculating the offset between n-1 relative coordinate values ​​and the standard coordinate value;

[0021] S800, statistically calculates the offset data, and converts it into signal jitter time in combination with the movement speed of the robot, or directly evaluates the jitter amplitude by the offset.

[0022] Preferably, the maximum allowable range of the code point offset is set to 10 mm. If the code point offset exceeds this threshold, it is considered that the signal transmission is unstable.

[0023] Preferably, the signal jitter evaluation process uses multiple sampling, and the sampling is repeated 2000 times to obtain n-1 deviation data to evaluate the signal jitter amplitude.

[0024] Preferably, the statistical method of the offset data comprises the following steps:

[0025] S810, calculating the mean of the offset data to reflect the overall jitter of the signal;

[0026] S820, calculating the standard deviation of the offset, which is used to evaluate the discreteness of the signal jitter amplitude;

[0027] S830, calculating the difference (range) between the maximum offset and the minimum offset to evaluate the maximum jitter amplitude of the signal;

[0028] S840. Use the 90th or 95th percentile to evaluate the jitter range of the signal in most cases.

[0029] Preferably, the method does not introduce a system error compensation mechanism, and the evaluation goal is to directly evaluate the stability of the system by counting the signal offset under network fluctuations, mechanical jitter, temperature changes and system errors.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention analyzes the offset of the coding point in the image taken by the camera and calculates the signal jitter time or offset amplitude to evaluate the stability of signal transmission; and through this method, the trigger signal stability of the robot terminal camera can be systematically evaluated, and combined with the complexity of the industrial production environment, the jitter situation in the signal transmission process can be comprehensively analyzed to ensure the detection accuracy and stability in industrial operations such as gluing and welding.

[0032] 2. The present invention is not limited to improving the response speed and hardware performance of the camera, but conducts stability analysis from the entire signal transmission process to provide a solution for systematically evaluating the stability of trigger signal transmission.

[0033] 3. The present invention comprehensively evaluates the jitter of the signal in a complex environment through multiple sampling and statistical analysis, and is more suitable for gluing and welding scenarios in actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flowchart of the evaluation method of the present invention; DETAILED DESCRIPTION

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The following is a further description with reference to the accompanying drawings and specific embodiments:

[0037] like Figure 1 As shown, an evaluation method for analyzing the stability of the robot end trigger signal is applicable to scenarios such as gluing and welding systems. The method includes the following steps:

[0038] 1. Camera installation and trigger signal setting

[0039] 1) Camera installation: The camera is fixed to the end of the robot, and the robot performs industrial operations (such as gluing or welding) according to a predetermined program. The camera is used to capture images of specific locations during industrial operations.

[0040] 2) Trigger signal source: The trigger signal of the camera is sent by the IO module of the robot controller, and the camera shooting is controlled by the external trigger signal. After each trigger signal of the IO module is sent, the camera control mainboard receives the signal and immediately executes the shooting task.

[0041] 3) Trigger time processing: The total time from the robot controller sending a signal to the camera completing the shooting action is the evaluation object. This method does not count the time from the camera control mainboard receiving the signal to the camera completing the shooting action (this time is usually at the microsecond level and can be ignored), but focuses on evaluating the stability of the trigger signal during the entire signal transmission process.

[0042] 2. Signal stability evaluation process

[0043] 1) Obtaining code point information: The robot moves to the specified shooting position, and the camera captures an image containing code point information according to an external trigger signal, and obtains the position coordinates of the code point in the camera coordinate system. The code point is used to calibrate and analyze the position information in the image related to actual industrial operations.

[0044] 2) Multiple sampling: The robot passes through the shooting point at a stable speed. Each time it passes, the camera captures an image based on the trigger signal and extracts the coded point information from the image. Repeatedly capture multiple images to obtain n sets of data for offset analysis, as follows:

[0045] (1) Capture the first image and extract the encoding point position as the standard coordinate value x, y, z;

[0046] (2) Collect each subsequent image and extract the coordinate values ​​x0, y0, z0, ..., xn-1, yn-1, zn-1 of the coding point relative to the standard position;

[0047] (3) Calculate the offset: According to the difference between the relative coordinates of the encoding point and the standard coordinates, calculate the offsets Δx and Δy in the x-axis and y-axis directions respectively. The formulas are as follows: Δxi = xi-x, Δyi = yi-y, i = 1, 2, ..., n-1;

[0048] (4) Total offset: The total amount of two-dimensional offset is calculated to evaluate the offset of the camera relative to the standard position:

[0049]

[0050] 3) Convert the offset into jitter time: The offset captured by the camera is combined with the movement speed of the robot arm to convert it into the corresponding signal jitter time Δt. The formula is:

[0051]

[0052] Where v is the moving speed of the robot arm, Δd i is the offset of the i-th image acquisition, Δt i is the corresponding signal jitter time, which reflects the jitter amplitude of the trigger signal in multiple cycles.

[0053] 4) Statistical analysis: After collecting n-1 offsets, perform signal stability evaluation. Signal evaluation statistically analyzes the following indicators:

[0054] (1) Mean: Calculate the average value of all offsets to reflect the overall jitter level of the signal. The formula is as follows:

[0055]

[0056] (2) Standard Deviation (σ): reflects the discreteness of the offset distribution and measures the amplitude of signal jitter. The formula is:

[0057]

[0058] (3) Range: The range of signal jitter is evaluated by the difference between the maximum offset and the minimum offset:

[0059] Range=Δd max -Δd min

[0060] (4) Percentile: Use the 90th or 95th percentile to evaluate the signal jitter range for most tests. If the jitter value of the high percentile is still within the set threshold, the signal transmission stability of the system is good.

[0061] 3. Signal threshold setting

[0062] According to the stability requirements of signal transmission during robot movement, the maximum allowable range of offset is set to 10mm. When the calculated offset exceeds 10mm, the signal transmission is considered unstable. The offset is converted into a time threshold through the robot speed (500mm / s), and the formula is:

[0063]

[0064] That is, the signal jitter time should not exceed 20ms. If it exceeds this value, the signal transmission is considered unstable.

[0065] 4. Repeat the test

[0066] In order to ensure the validity of statistical data and the accuracy of evaluation results, this method performs 2000 samplings and finally obtains 1999 deviation data. By performing statistical analysis on these 1999 sets of data, the jitter amplitude of the signal and the stability of the system are determined.

[0067] Examples of practical application scenarios

[0068] Example 1, Gluing system: During the gluing process, the quality of the glue strip depends on the camera's accurate detection of the glue strip position. If the trigger signal is unstable, the image of the glue strip taken by the camera may be biased, affecting the accuracy of the detection result. This method can effectively evaluate the stability of the trigger signal, thereby ensuring the detection accuracy of the gluing system.

[0069] Example 2, welding system: During the welding process, the accurate detection of parameters such as the position and depth of the weld also depends on the stable triggering of the camera. This method can evaluate the stability of the camera signal transmission during the welding process by analyzing the signal jitter time, thereby ensuring the accuracy of welding quality detection.

[0070] Compared with the prior art, the present invention is not limited to improving the hardware response speed, but systematically evaluates the stability of the entire signal transmission process. Most existing methods focus on optimizing the performance of camera hardware, while ignoring the impact of external environmental factors (such as network fluctuations, mechanical jitter, temperature changes, etc.) on signal transmission. The present invention comprehensively evaluates the jitter of the signal in a complex environment through multiple sampling and statistical analysis, which is more suitable for gluing and welding scenarios in actual production.

[0071] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for evaluating the stability of a robot end trigger signal, characterized in that: The specific steps of this method are as follows: S100, installing a camera at the end of the robot, wherein the camera works through an external trigger signal, the trigger signal is sent by an IO module of the robot controller, and triggers the camera to acquire an image; S200, the image captured by the camera contains information of coded points marked, where the coded points are used to evaluate signal stability; S300, when the robot is controlled by program instructions to move to a photographing position at a stable speed, a trigger signal is sent and an image is collected; S400, collecting images containing coding point information, extracting the position coordinates of the coding points in the camera coordinate system through image processing, using multiple sampling methods to obtain multiple groups of data and perform signal jitter analysis.

2. The method for evaluating the stability of a robot end trigger signal according to claim 1, characterized in that: In step S400, the signal jitter is evaluated by analyzing the code point offsets collected multiple times, which specifically includes the following steps: S410, collecting a first image containing coded point information, and extracting coordinate information of the coded point in the camera coordinate system as a standard position coordinate value; S420, collecting subsequent images, and extracting the relative position coordinate values ​​of the coding points in each image; S430, counting the offsets of the relative position coordinate values ​​of the encoding points of the subsequent n-1 images and the standard position coordinate values ​​in the x and y directions; S440, using the offset in combination with the movement speed of the manipulator to convert into a signal jitter time, or directly evaluating the stability of the signal based on the offset.

3. The method for evaluating the stability of a robot end trigger signal according to claim 1, characterized in that: The camera control mainboard receives the trigger signal and controls the camera shooting. The trigger signal transmission and the camera shooting action are treated as a whole. The system stability evaluation ignores the time between the camera receiving the signal and executing the shooting, because the time is at the microsecond level.

4. A method for evaluating the stability of a robot end trigger signal according to any one of claims 1 to 3, characterized in that: It also includes the signal stability evaluation process, the specific steps are: S500, extracting the position information of the coding point by image processing technology, and converting it into coordinate values ​​in the camera coordinate system; S600, taking the coding point position of the first image as a standard and the coding point positions in other images as relative coordinate values; S700, calculating the offset between n-1 relative coordinate values ​​and the standard coordinate value; S800, statistically calculates the offset data, and converts it into signal jitter time in combination with the movement speed of the robot, or directly evaluates the jitter amplitude by the offset.

5. The method for evaluating the stability of a robot end trigger signal according to claim 4, characterized in that: The maximum allowable range of the code point offset is set to 10 mm. If the code point offset exceeds this threshold, it is considered that the signal transmission is unstable.

6. The method for evaluating the stability of a robot end trigger signal according to claim 4, characterized in that: The signal jitter evaluation process adopts multiple sampling, and the sampling is repeated 2000 times to obtain n-1 deviation data to evaluate the signal jitter amplitude.

7. The method for evaluating the stability of a robot end trigger signal according to claim 6, characterized in that: The statistical method of the offset data comprises the following steps: S810, calculating the mean of the offset data to reflect the overall jitter of the signal; S820, calculating the standard deviation of the offset, which is used to evaluate the discreteness of the signal jitter amplitude; S830, calculating the difference (range) between the maximum offset and the minimum offset to evaluate the maximum jitter amplitude of the signal; S840. Use the 90th or 95th percentile to evaluate the jitter range of the signal in most cases.

8. The method for evaluating the stability of a robot end trigger signal according to claim 1, characterized in that: This method does not introduce a system error compensation mechanism. The evaluation goal is to count the signal offset under network fluctuations, mechanical jitter, temperature changes and system errors to directly evaluate the stability of the system.

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