Workpiece positioning abnormality determination method for servo positioning device and device thereof

Abstract

The application discloses a workpiece positioning abnormality determination method and device capable of automatically detecting workpiece positioning abnormality of a servo positioning device, and the workpiece positioning abnormality determination method comprises the following steps: acquiring a first torque output value of at least one positioning shaft of the servo positioning device in a first predetermined time length; acquiring a second torque output value of the positioning shaft in a second predetermined time length; and determining that workpiece positioning is abnormal when the second torque output value deviates from the first torque output value by more than a predetermined degree.

Description

TECHNICAL FIELD

[0001] The present application relates to the production manufacturing field, and particularly relates to a workpiece positioning abnormality determination method for a servo positioning device and a device thereof. BACKGROUND

[0002] The NC locator is a servo positioning device developed according to the flexible production requirements of the automobile industry user body welding production line. The servo positioning device (NC locator) can realize XYZ three-axis (X-axis, Y-axis, Z-axis three positioning axes) linkage, wherein the X-axis realizes longitudinal reciprocating movement, the Y-axis realizes transverse reciprocating movement, and the Z-axis realizes lifting reciprocating movement. According to the positioning hole position of different workpieces, the positioning pin and the air cylinder at the top of the Z-axis or other parts complete the positioning clamping task to realize accurate positioning.

[0003] In one production, the servo positioning device will go through three processes: 1. The servo positioning device starts from the empty state to bear the vehicle body (hereinafter referred to as Step No1, workpiece loading stage); 2. The servo positioning device bears the vehicle body while the robot performs welding (hereinafter referred to as Step No2, workpiece processing stage); 3. The vehicle body on the servo positioning device is removed, and the NC re-enters the empty state (hereinafter referred to as Step No3, workpiece unloading stage). Figure 1 The output torque curve diagram of the servo positioning device in one production is shown.

[0004] Among them, the product quality is mainly divided into three factors, which are: 1. Poor servo positioning device equipment precision; 2. Poor robot precision; 3. Poor vehicle body precision. At present, the causes of product quality problems are mainly judged by manual work, and then improved accordingly, which makes the discovery of quality problems not only exist serious lag, but also time-consuming and laborious, and the workers have a large working strength, and the judgment error is easy to produce. SUMMARY

[0005] In view of the above problems, one object of the present application is to provide a workpiece positioning abnormality determination method for a servo positioning device and a device thereof, which can automatically analyze and judge the causes of product quality problems and reduce the working strength of workers.

[0006] Another object of the present application is to provide a workpiece positioning abnormality determination method for a servo positioning device and a device thereof, which can reduce the judgment error of the causes of product quality problems.

[0007] In order to achieve at least one of the above objects, the present application adopts the following technical solutions:

[0008] A workpiece positioning abnormality determination method for a servo positioning device, comprising the following steps:

[0009] acquiring a first torque output value of at least one positioning axis of the servo positioning device for a first predetermined time length;

[0010] acquiring a second torque output value of the positioning axis for a second predetermined time length;

[0011] determining that workpiece positioning is abnormal when the second torque output value deviates from the first torque output value by more than a predetermined degree.

[0012] As a preferred embodiment, the first predetermined time length is greater than the second predetermined time length, and the first predetermined time length and the second predetermined time length are consecutive time lengths.

[0013] As a preferred embodiment, the first predetermined time length is more than 5 times the second predetermined time length.

[0014] As a preferred embodiment, the first torque output value and the second torque output value are maximum torque output values in a workpiece loading stage.

[0015] As a preferred embodiment, the first torque output value and the second torque output value are maximum torque output values in a workpiece loading stage.

[0016] As a preferred embodiment, the first torque output value is an average of maximum torque output values in a workpiece loading stage in the first predetermined time length, and the second torque output value is an average of maximum torque output values in a workpiece loading stage in the second predetermined time length.

[0017] As a preferred embodiment, when the second torque output value is greater than the first torque output value by a first predetermined multiple, it is determined that the workpiece precision is abnormal; the first predetermined multiple is not less than 1.05 times.

[0018] As a preferred embodiment, when the second torque output value is less than the first torque output value by a second predetermined multiple, it is determined that the positioning end of the servo positioning device is abnormal; the second predetermined multiple is not more than 0.95 times.

[0019] As a preferred embodiment, the first torque output value and the second torque output value are minimum torque output values in a workpiece unloading stage.

[0020] As a preferred embodiment, the first torque output value is an average of minimum torque output values in a workpiece unloading stage in the first predetermined time length, and the second torque output value is an average of minimum torque output values in a workpiece unloading stage in the second predetermined time length.

[0021] As a preferred embodiment, when the second torque output value is less than the first torque output value by a third predetermined multiple, it is determined that the workpiece precision is abnormal; the third predetermined multiple is not higher than 0.95 times.

[0022] As a preferred embodiment, when the second torque output value is greater than the first torque output value by a fourth predetermined multiple, it is determined that the positioning end of the servo positioning device is abnormal; the second predetermined multiple is not less than 1.05 times.

[0023] As a preferred embodiment, the first torque output value and the second torque output value are average torque output values in the workpiece processing stage.

[0024] As a preferred embodiment, the first torque output value is an average torque output value in the workpiece processing stage in a first predetermined time length; and the second torque output value is an average torque output value in the workpiece processing stage in a second predetermined time length.

[0025] As a preferred embodiment, when the second torque output value is greater than the first torque output value by a fifth predetermined multiple, it is determined that the output torque of the servo positioning device is too large; the fifth predetermined multiple is not less than 1.05 times.

[0026] A workpiece positioning abnormality determination device for a servo positioning device, comprising the following steps:

[0027] A first acquisition module is configured to acquire a first torque output value of at least one positioning axis of the servo positioning device in a first predetermined time length;

[0028] A second acquisition module is configured to acquire a second torque output value of the positioning axis in a second predetermined time length;

[0029] An abnormality determination module is configured to determine that the workpiece positioning is abnormal when the second torque output value deviates from the first torque output value by more than a predetermined degree.

[0030] Advantages:

[0031] In the workpiece positioning abnormality determination method provided in the embodiment, when the second torque output value is higher than the first torque output value by more than a predetermined threshold value or the second torque output value is lower than the first torque output value by more than a predetermined threshold value, it indicates that the deviation between the first torque output value and the second torque output value is too large, thereby confirming that the workpiece positioning is abnormal, and at this time, an alarm can be given to remind the on-site workers to check. Therefore, the workpiece positioning abnormality determination method provided in the embodiment can automatically analyze and judge the causes of product quality problems, thereby reducing the work intensity of workers.

[0032] The particular embodiments of the application will be described in relation to the enclosed drawings as best described below, as an illustration of the principles of the application that can be employed in practicing the application. It is understood that the embodiments of the application are not limited in scope to the

[0033] Features described and / or illustrated with respect to one embodiment can be used in one or more other embodiments in the same or similar manner, in combination with or in place of one or more features of the other embodiments.

[0034] It should be emphasized that the term "comprises / comprising" when used in this specification is taken to mean the presence of stated features, integers, steps or components but not to the exclusion of one or more other features, integers, steps, components or groups thereof. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0036] Figure 1 The output torque curve in the servo positioning device is shown in the figure;

[0037] Figure 2 It is a workpiece positioning abnormality determination method flowchart provided by an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the technical personnel in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0039] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or there can be one or more intervening elements present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. As used herein the terms "vertical", "horizontal", "left", "right", and the like are used for illustration and not limitation.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0041] Referring to Figure 2 An embodiment of the present application provides a workpiece positioning abnormality determination method for a servo positioning device, comprising the following steps:

[0042] S100, acquiring a first torque output value of at least one positioning axis of the servo positioning device for a first predetermined time length;

[0043] S200, acquiring a second torque output value of the positioning axis for a second predetermined time length;

[0044] S300, determining that workpiece positioning is abnormal when the second torque output value deviates from the first torque output value by more than a predetermined degree.

[0045] In the workpiece positioning abnormality determination method provided by the embodiment, when the second torque output value is higher than the first torque output value by more than a predetermined threshold or the second torque output value is lower than the first torque output value by more than a predetermined threshold, it is confirmed that the deviation between the first torque output value and the second torque output value is too large, and thus it is determined that the workpiece positioning is abnormal. At this time, an alarm can be given to remind the on-site workers to check. Therefore, the workpiece positioning abnormality determination method provided by the embodiment can automatically analyze and determine the cause of the occurrence of product quality problems, and reduce the working intensity of workers.

[0046] Considering that the workpiece undergoes a workpiece loading stage, a workpiece machining stage, and a workpiece unloading stage in the entire machining stage, accordingly, the first torque output value and the second torque output value are compared by using values in the same stage. For example, Figure 1 As shown in the figure, in the workpiece loading stage, the servo positioning device has a maximum output torque, in the entire workpiece machining stage, the output torque of the servo positioning device is roughly constant (with slight fluctuations), and in the workpiece unloading stage, similar to the loading stage, there is a minimum output torque.

[0047] In the embodiment, the first predetermined time length and the second predetermined time length each include a plurality of workpiece complete machining processes, including the machining process of the workpiece from the loading stage to the unloading stage. The first predetermined time length is greater than the second predetermined time length, and the first predetermined time length and the second predetermined time length are continuous time lengths. The first predetermined time length is more than 5 times the second predetermined time length. For example, the first predetermined time length can be more than 5 hours or more than 1 day. In some embodiments, the first predetermined time length and the second predetermined time length can be 1 day, so as to determine whether there is a problem with the product quality of the day.

[0048] In steps S100 and S200, the first torque output value and the second torque output value of each positioning axis of the XYZ axes of the servo positioning device are obtained. The second predetermined time length is later than the first predetermined time length. The first torque output value includes at least one of the maximum torque output value in the workpiece loading stage, the average torque output value in the workpiece machining stage, and the minimum torque output value in the workpiece unloading stage, and the second torque output value includes at least one of the maximum torque output value in the workpiece loading stage, the average torque output value in the workpiece machining stage, and the minimum torque output value in the workpiece unloading stage.

[0049] Specifically, the first torque output value can be the average value of each workpiece machining stage or machining stage or unloading stage of the workpiece obtained by calculation, or the average value of the workpiece machining stage or machining stage or unloading stage of each day. The second torque output value can be the average value of each workpiece machining stage or machining stage or unloading stage of the workpiece obtained by calculation, or the average value of the workpiece machining stage or machining stage or unloading stage of each day.

[0050] In the embodiment, the first torque output value and the second torque output value are the maximum torque output values in the workpiece loading stage. Specifically, the first torque output value is the average value of the maximum torque output values in the workpiece loading stage in the first predetermined time length. The second torque output value is the average value of the maximum torque output values in the workpiece loading stage in the second predetermined time length.

[0051] When the second torque output value is greater than the first torque output value by a first predetermined multiple, it is determined that the workpiece precision is abnormal; the first predetermined multiple is not less than 1.05 times.

[0052] determining that the positioning end of the servo positioning device is abnormal when the second torque output value is less than the first torque output value by a second predetermined multiple; the second predetermined multiple being no more than 0.95 times. In this embodiment, the sum of the first predetermined multiple and the second predetermined multiple is 2. Of course, the first predetermined multiple, the second predetermined multiple, the third predetermined multiple, the fourth predetermined multiple, and the fifth predetermined multiple can be set as desired, and are not fixed values. For example, the workpiece positioning abnormality determination method can also have a setting step for setting at least one of the first predetermined multiple, the second predetermined multiple, the third predetermined multiple, the fourth predetermined multiple, and the fifth predetermined multiple.

[0053] In this embodiment, the first torque output value and the second torque output value include average torque output values in the workpiece machining phase. Specifically, the first torque output value is an average torque output value in the workpiece machining phase in a first predetermined time period; and the second torque output value is an average torque output value in the workpiece machining phase in a second predetermined time period. Further, when the second torque output value is greater than the first torque output value by a fifth predetermined multiple, it is determined that the output torque of the servo positioning device is too large; the fifth predetermined multiple being no less than 1.05 times.

[0054] A specific application embodiment of the present application will be described in detail below to better understand the present application:

[0055] Torque output data of each positioning axis of the servo positioning device for a period of time (a days, a ≥ 1) is intercepted, with the previous 90% time period (first predetermined time period) as reference data and the last 10% time period (second predetermined time period) as examination data. (a days can be set according to customer requirements, and in addition, 90% and 10% here can also be changed according to requirements.)

[0056] Whether the robot welding is abnormal is examined using the torque output data of each positioning axis of Step No2 (workpiece machining phase), and the average torque output value (first torque output value, second torque output value) of each day is calculated to compare the first torque output value and the second torque output value of each positioning axis.

[0057] If the average torque output value (second torque output value) of Step No2 (workpiece processing stage) per day in the last 10% of the observation period > 1.1 * the average torque output value (first torque output value) of Step No2 per day in the first 90% of the observation period, it indicates that the output torque of the servo positioning device (NC locator) during production is too large and exceeds the normal range. If the average torque output value (second torque output value) per day in the last 10% of the observation period ≤ 1.1 * the average torque output value (first torque output value) of Step No2 per day in the first 90% of the observation period, it indicates that the output torque of the servo positioning device (NC locator) during production is within the normal range and positioning is not abnormal.

[0058] If the maximum torque output value (second torque output value) of Step No1 (workpiece loading stage) per day in the last 10% of the observation period > 1.1 * the maximum torque output value (first torque output value) of Step No1 per day in the first 90% of the observation period, it indicates that the servo positioning device is subjected to excessive resistance when receiving the workpiece, indicating poor workpiece precision.

[0059] If the maximum torque output value (second torque output value) of Step No1 (workpiece loading stage) per day in the last 10% of the observation period < 0.9 * the maximum torque output value (first torque output value) of Step No1 per day in the first 90% of the observation period, it indicates that the servo positioning device is subjected to small resistance when receiving the workpiece, but the resistance is large during actual welding, indicating that the positioning end of the servo positioning device has deformed and is more fitted to the position of the workpiece, the overall precision is reduced, resulting in a deviation between the teaching point position and the actual point position during spot welding.

[0060] In a specific embodiment, considering that the output torque curves of the workpiece loading stage and the workpiece unloading stage are similar (moving in opposite directions, the maximum output torque appears in the workpiece loading stage, the minimum output torque appears in the workpiece unloading stage, and after experiencing the maximum output torque and the minimum output torque, the output torque appears an inflection point), the first torque output value and the second torque output value are the minimum torque output value in the workpiece unloading stage.

[0061] The first torque output value is the average value of the minimum torque output value in the workpiece unloading stage in the first predetermined time period or the minimum torque output value of the workpiece unloading stage per day. The second torque output value is the average value of the minimum torque output value in the workpiece unloading stage in the second predetermined time period.

[0062] When the second torque output value is less than a first torque output value by a third predetermined multiple, it is determined that the workpiece precision is abnormal; the third predetermined multiple is not higher than 0.95 times. When the second torque output value is greater than the first torque output value by a fourth predetermined multiple, it is determined that the positioning end of the servo positioning device is abnormal; the second predetermined multiple is not less than 1.05 times. For example, when the second torque output value is less than 0.9 times the first torque output value, it is determined that the workpiece precision is abnormal, where the workpiece precision is poor, and the abnormality may be caused by poor machining precision of a previous process line; when the second torque output value is greater than 1.1 times the first torque output value,

[0063] The workpiece positioning abnormality determination method also has a step of visualizing the abnormality, in which a pie chart and a line chart are displayed according to the proportion of each fault cause per day. The pie chart can clearly show the cause of the reduction in machining quality, and the line chart can show the development trend of each fault cause.

[0064] The workpiece positioning abnormality determination method provided by the embodiment has the following advantages:

[0065] 1) By classifying and analyzing the fault causes, the main cause of the fault can be roughly inferred, and the customer can be helped to perform a more targeted inspection, for example, the largest area of the pie chart indicates that this cause is most likely to cause the fault.

[0066] 2) By observing the changes along the time axis as a whole, the misjudgment can be avoided to some extent.

[0067] 3) By certain monitoring and observation, the best maintenance time can be inferred, the number of invalid maintenance can be reduced, the maintenance cost can be reduced, the production efficiency can be improved, the product quality can be ensured, and the trend of the fault cause can be observed through the line chart.

[0068] The application also has an embodiment providing a workpiece positioning abnormality determination device for a servo positioning device, comprising: a first acquisition module configured to acquire a first torque output value of at least one positioning axis of the servo positioning device for a first predetermined time length; a second acquisition module configured to acquire a second torque output value of the positioning axis for a second predetermined time length; and an abnormality determination module configured to determine that workpiece positioning is abnormal when the first torque output value deviates from the second torque output value by a predetermined degree.

[0069] Any numerical values recited herein include all values from the lower value and up to the upper value in increments of one unit, provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if a numerical value is recited as being from 1 to 90, preferably from 20 to 80, and more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, and 30 to 32, etc. are expressly enumerated in this specification. For values which are less than one, one unit is considered to be 0.0001, 0.001, 0.01, 0.1, as appropriate. These are only examples of what is specifically enumerated herein, and are not meant to limit the application in any way. Furthermore, the inclusion of a numerical range recited herein is not intended to exclude any gyrations from the scope of the range, as appropriately interpreted, unless the context clearly indicates otherwise.

[0070] All ranges are inclusive of the endpoints and of all numbers between the endpoints, unless otherwise indicated. "About" or "approximately," when used to describe a range, is meant to encompass the two endpoints of the range as well as all numbers in between. Thus, "about 20 to 30" is intended to cover "about 20 to about 30," including at least the specified endpoints.

[0071] All articles and references, including patent applications and publications, disclosed below are incorporated herein by reference for all purposes. The term "consisting essentially of to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the term "comprising" or "including" to describe combinations of elements, ingredients, components or steps herein also is taken to mean that other elements, ingredients, components or steps can be present in addition to those specifically recited, in order to achieve the described functionality of the combination. The term "comprising" as used herein is intended to indicate an open group, including "consisting essentially of. The use of the term "comprising" also includes the use of the term "including," "containing," or "characterized by," and vice versa.

[0072] Multiple elements, ingredients, components or steps can be provided by a single integrated element, ingredient, component or step. Alternatively, a single integrated element, ingredient, component or step might be divided into separate multiple elements, ingredients, components or steps. To "comprise" or "comprising," as used herein, means to "include" or "including," but not to the exclusion of other elements, ingredients, components or steps.

[0073] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the examples provided would be apparent upon reading the above description. The scope of the teachings should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. The omission in the following claims of any aspect of subject matter that is disclosed herein is not a disclaimer of such subject matter, nor should it be regarded that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A method for determining workpiece positioning anomalies using a servo positioning device, characterized in that, The method comprises the following steps: acquiring a first torque output value of at least one positioning axis of the servo positioning device for a first predetermined time length; acquiring a second torque output value of the positioning axis for a second predetermined time length; determining that workpiece positioning is abnormal when the second torque output value deviates from the first torque output value by more than a predetermined degree; the first torque output value and the second torque output value are maximum torque output values in a workpiece loading stage; the first torque output value is an average of maximum torque output values in a workpiece loading stage in the first predetermined time length; the second torque output value is an average of maximum torque output values in a workpiece loading stage in the second predetermined time length; when the second torque output value is greater than the first torque output value by a first predetermined multiple, it is determined that workpiece precision is abnormal; the first predetermined multiple is not less than 1.05 times; when the second torque output value is less than the first torque output value by a second predetermined multiple, it is determined that a positioning end of the servo positioning device is abnormal; the second predetermined multiple is not more than 0.95 times; and / or, the first torque output value and the second torque output value are minimum torque output values in a workpiece unloading stage; the first torque output value is an average of minimum torque output values in a workpiece unloading stage in the first predetermined time length; the second torque output value is an average of minimum torque output values in a workpiece unloading stage in the second predetermined time length; when the second torque output value is less than the first torque output value by a third predetermined multiple, it is determined that workpiece precision is abnormal; the third predetermined multiple is not more than 0.95 times; when the second torque output value is greater than the first torque output value by a fourth predetermined multiple, it is determined that a positioning end of the servo positioning device is abnormal; the second predetermined multiple is not less than 1.05 times.

2. The workpiece positioning abnormality determination method according to Claim 1, characterized by, The first predetermined time length is greater than the second predetermined time length, and the first predetermined time length and the second predetermined time length are continuous time lengths.

3. The workpiece positioning abnormality determination method according to Claim 2, characterized by, The first predetermined time length is more than 5 times the second predetermined time length.

4. The workpiece positioning abnormality determination method according to Claim 1, characterized by, The first torque output value is acquired for each positioning axis of XYZ axes of the servo positioning device.

5. The workpiece positioning abnormality determination method according to Claim 1, characterized by, The first torque output value and the second torque output value are average torque output values in a workpiece processing stage.

6. The workpiece positioning abnormality determination method according to Claim 5, characterized by, The first torque output value is an average torque output value in a workpiece processing stage in the first predetermined time length; the second torque output value is an average torque output value in a workpiece processing stage in the second predetermined time length.

7. The workpiece positioning abnormality determination method according to Claim 6, characterized by, When the second torque output value is greater than the first torque output value by a fifth predetermined multiple, it is determined that the output torque of the servo positioning device is too large; the fifth predetermined multiple is not less than 1.05 times.

8. A workpiece positioning anomaly determination device for a servo positioning device, characterized in that, The method comprises the following steps: a first acquisition module is configured to acquire a first torque output value of at least one positioning axis of the servo positioning device for a first predetermined time length; a second acquisition module is configured to acquire a second torque output value of the positioning axis for a second predetermined time length; an abnormality determination module is configured to determine that workpiece positioning is abnormal when the second torque output value deviates from the first torque output value by more than a predetermined degree; the first torque output value and the second torque output value are maximum torque output values in a workpiece loading stage; The first torque output value is an average of maximum torque output values in a workpiece loading stage in a first predetermined time length; the second torque output value is an average of maximum torque output values in the workpiece loading stage in a second predetermined time length; when the second torque output value is greater than the first torque output value by a first predetermined multiple, it is determined that the workpiece precision is abnormal; The first predetermined multiple is not less than 1.05 times; when the second torque output value is less than the first torque output value by a second predetermined multiple, it is determined that the positioning end of the servo positioning device is abnormal; The second predetermined multiple is not more than 0.95 times; And / or, The first torque output value and the second torque output value are minimum torque output values in a workpiece unloading stage; The first torque output value is an average of minimum torque output values in a workpiece unloading stage in a first predetermined time length; the second torque output value is an average of minimum torque output values in the workpiece unloading stage in a second predetermined time length; when the second torque output value is less than the first torque output value by a third predetermined multiple, it is determined that the workpiece precision is abnormal; The third predetermined multiple is not more than 0.95 times; when the second torque output value is greater than the first torque output value by a fourth predetermined multiple, it is determined that the positioning end of the servo positioning device is abnormal; The second predetermined multiple is not less than 1.05 times.

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