A method for precisely controlling the depth of counter-sinking

Abstract

The application discloses a kind of accurate control methods of counterbore depth, and error compensation is realized to the counterbore equipment and the surface of workpiece to accurately control counterbore depth, comprising: the outer closed loop control of tool feed is used to realize mechanical clearance compensation in tool feed process;High-precision tool setting gauge is used to measure tool length, and tool wear compensation is realized;High-precision displacement sensor is installed on pressure foot feed shaft to realize workpiece deformation compensation;High-precision distance measuring sensor is installed on pressure foot to measure normal vector, and error compensation of counterbore depth is realized by normal vector correction;Curvature analysis is carried out to the edge surface of counterbore, and curvature error compensation is realized.The application can realize high-precision control of weak rigid surface counterbore depth.

Description

Technical Field

[0001] This invention relates to the field of hole-making technology, specifically to a method for precise control of countersink depth. Background Technology

[0002] The key to accurately controlling the countersink depth is precisely controlling the relative position of the tool and the workpiece. However, during the hole-making process, the tool length, the normal vector of the tool and workpiece surfaces, the tool feed accuracy, the clamping force, and the axial cutting force all affect the precise control of the countersink depth due to the workpiece deformation in the tool feed direction and the curvature of the workpiece surface. For different types of surfaces, when the pressure foot clamps the workpiece along the normal direction, there is a deviation between the contact position of the pressure foot and the workpiece and the hole-making position in the tool feed direction. In actual machining, it is necessary to correct the tool feed depth to eliminate its impact on the countersink depth accuracy. During the countersinking process, the clamping force and axial cutting force cause the workpiece to deform in the tool feed direction. This deformation changes the precise relative position between the tool and the workpiece, reducing the tool feed depth and thus causing countersink depth errors. The feed axis positioning accuracy determines the motion accuracy of the tool in the feed direction, which is crucial to the countersink accuracy. Due to issues such as the rigidity of the feed axis and transmission backlash, the position feedback of the feed servo axis itself can lead to significant tool positioning errors. Summary of the Invention

[0003] This invention provides a method for precise control of countersink depth, which solves the technical problem of countersink depth control.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0005] A method for precisely controlling the depth of a countersink, comprising the following steps:

[0006] S1, Startup, program initialization and self-test, opening communication interface, establishing communication;

[0007] S2, Tool position detection: Tool position detection is required after each tool change using a tool setter;

[0008] S3, Normal Vector Adjustment: The angle between the normal vector of the pressure foot and the workpiece is calculated by the sensor on the pressure foot. Through multiple iterations, the angle between the tool direction and the normal vector of the workpiece is controlled within an acceptable range.

[0009] S4, Curvature Compensation: Calculates the deviation between the contact position of the pressure foot and the workpiece and the workpiece hole position in the tool feed direction, and corrects the tool feed depth.

[0010] S5, begin countersinking;

[0011] S6, Indenter Precision Compensation: Monitors workpiece deformation, obtains accurate deformation amount at countersink position, and compensates for tool feed;

[0012] S7, Feed accuracy error compensation: The feed axis is equipped with a high-precision grating as an external position feedback sensor, and the minimum positioning accuracy is guaranteed to be no less than 0.005mm through an external full closed-loop control algorithm;

[0013] S8, countersinking complete.

[0014] In step S3, four high-precision distance sensors are installed on the pressure foot. The included angle between the sensors is 90°. When the pressure foot contacts the workpiece, the four sensors can measure the distance to the workpiece. The normal angle between the pressure foot and the workpiece can be calculated using the data from the four sensors.

[0015] The formula for calculating the included normal angle in step S3 is:

[0016]

[0017]

[0018] in β is the angle in the X direction, l is the angle in the Y direction, s1, s2, s3, s4 represent the values ​​of the four range sensor readings after horizontal linearization, and θ represents the tilt angle of the range sensor.

[0019] The calculation of the deviation between the contact position of the pressure foot and the workpiece and the workpiece hole-making position in the tool feed direction in step S4 is divided into the following four categories:

[0020] a. When the workpiece surface is a spherical convex surface, the correction amount for the tool feed depth is:

[0021]

[0022] b. When the workpiece surface is a concave surface similar to a sphere, the correction amount for the tool feed depth is:

[0023]

[0024] c. When the workpiece surface is a cylindrical convex surface, the pressure foot detection error is 0, and the correction amount for the tool feed depth is:

[0025]

[0026] d. When the workpiece surface is a cylindrical concave surface, the tool feed depth correction is:

[0027]

[0028] Where r ph_in The radius r represents the inner circle radius of the pressure foot end face. ph_outThe radius r represents the outer circle radius of the pressure foot end face. hl R represents the radius of the countersink hole, and R is the workpiece radius of curvature.

[0029] In step S6, a high-precision grating ruler is used on the clamping shaft to achieve high-precision detection of the workpiece deformation, and the overall accuracy of the clamping shaft displacement detection is controlled within 0.005mm.

[0030] Based on the above technical solution, the following technical effects can be achieved:

[0031] This invention achieves precise control of countersink depth through error compensation between the countersinking equipment and the workpiece surface. This includes: compensating for mechanical backlash during tool feed through external closed-loop control; compensating for tool wear by measuring tool length using a high-precision tool setter; compensating for workpiece deformation by installing a high-precision displacement sensor on the pressure foot feed axis; compensating for countersink depth error by installing a high-precision distance sensor on the pressure foot for normal vector measurement and correction; and compensating for actual curvature error by analyzing the surface curvature of the countersink edge. The system can achieve high-precision control of countersink depth on weakly rigid curved surfaces. Attached Figure Description

[0032] Figure 1 This is the control flowchart of the present invention;

[0033] Figure 2 This is a system control composition diagram of the present invention;

[0034] Figure 3 This is the control principle diagram of the present invention;

[0035] Figure 4 This is a schematic diagram of the convex surface of the pressure foot contact ball in this invention;

[0036] Figure 5 This is a schematic diagram of the concave surface of the pressure foot contact ball in this invention;

[0037] Figure 6 This is a schematic diagram of the pressure foot contact columnar convex surface in this invention;

[0038] Figure 7 This is a schematic diagram of the concave surface of the pressure foot contact column in this invention. Detailed Implementation

[0039] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0040] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0041] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] like Figures 1-7 As shown, a method for precise control of countersink depth includes the following steps:

[0044] S1, Startup, program initialization and self-test, opening communication interface, establishing communication;

[0045] S2, Tool position detection: Tool position detection is required after each tool change using a tool setter;

[0046] S3, Normal Vector Adjustment: The angle between the normal vector of the pressure foot and the workpiece is calculated by the sensor on the pressure foot. Through multiple iterations, the angle between the tool direction and the normal vector of the workpiece is controlled within an acceptable range.

[0047] S4, Curvature Compensation: Calculates the deviation between the contact position of the pressure foot and the workpiece and the workpiece hole position in the tool feed direction, and corrects the tool feed depth.

[0048] S5, begin countersinking;

[0049] S6, Indenter Precision Compensation: Monitors workpiece deformation, obtains accurate deformation amount at countersink position, and compensates for tool feed;

[0050] S7, Feed accuracy error compensation: The feed axis is equipped with a high-precision grating as an external position feedback sensor, and the minimum positioning accuracy is guaranteed to be no less than 0.005mm through an external full closed-loop control algorithm;

[0051] S8, countersinking complete.

[0052] In step S3, four high-precision distance sensors are installed on the pressure foot. The included angle between the sensors is 90°. When the pressure foot contacts the workpiece, the four sensors can measure the distance to the workpiece. The normal angle between the pressure foot and the workpiece can be calculated using the data from the four sensors.

[0053] The formula for calculating the included normal angle in step S3 is:

[0054]

[0055]

[0056] in β is the angle in the X direction, l is the angle in the Y direction, s1, s2, s3, s4 represent the values ​​of the four range sensor readings after horizontal linearization, and θ represents the tilt angle of the range sensor.

[0057] The calculation of the deviation between the contact position of the pressure foot and the workpiece and the workpiece hole-making position in the tool feed direction in step S4 is divided into the following four categories:

[0058] a. When the workpiece surface is a spherical convex surface, such as Figure 4 As shown, the correction amount for the tool feed depth is:

[0059]

[0060] b. When the workpiece surface is a concave surface similar to a sphere, such as Figure 5 As shown, the correction amount for the tool feed depth is:

[0061]

[0062] c. When the workpiece surface is a cylindrical convex surface, such as Figure 6 As shown, the pressure foot detection error is 0. At this time, the correction amount for the tool feed depth is:

[0063]

[0064] d. When the workpiece surface is a concave cylindrical surface, such as Figure 7 As shown, the tool feed depth correction amount is:

[0065]

[0066] Where r ph_in The radius r represents the inner circle radius of the pressure foot end face. ph_out The radius r represents the outer circle radius of the pressure foot end face. hl R represents the radius of the countersink hole, and R is the workpiece radius of curvature.

[0067] In step S6, a high-precision grating ruler is used on the clamping shaft to achieve high-precision detection of the workpiece deformation, and the overall accuracy of the clamping shaft displacement detection is controlled within 0.005mm.

[0068] This invention provides a method for precise control of countersink depth. This method achieves precise control of countersink depth by compensating for errors between the countersinking equipment and the workpiece surface. The method includes: compensating for mechanical backlash during tool feeding through external closed-loop control of the tool feed; compensating for tool wear by measuring the tool length using a high-precision tool setter; compensating for workpiece deformation by installing a high-precision displacement sensor on the pressure foot feed axis; compensating for countersink depth errors by installing a high-precision distance sensor on the pressure foot and performing normal vector measurement and normal vector correction; and compensating for actual curvature errors by analyzing the surface curvature of the countersink edge.

[0069] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for precise control of countersink depth, characterized in that, Includes the following steps: S1, Startup, program initialization and self-test, opening communication interface, establishing communication; S2, Tool position detection: Tool position detection is required after each tool change using a tool setter; S3, Normal Vector Adjustment: The angle between the normal vector of the pressure foot and the workpiece is calculated by the sensor on the pressure foot. Through multiple iterations, the angle between the tool direction and the normal vector of the workpiece is controlled within an acceptable range. S4, Curvature Compensation: Calculates the deviation between the contact position of the pressure foot and the workpiece and the workpiece hole position in the tool feed direction, and corrects the tool feed depth. S5, begin countersinking; S6, Indenter Precision Compensation: Monitors workpiece deformation, obtains accurate deformation amount at countersink position, and compensates for tool feed; S7, Feed accuracy error compensation: The feed axis is equipped with a high-precision grating as an external position feedback sensor, and the minimum positioning accuracy is guaranteed to be no less than 0.005mm through an external full closed-loop control algorithm; S8, countersinking complete; In step S3, four high-precision distance sensors are installed on the pressure foot. The included angle between the sensors is 90°. When the pressure foot contacts the workpiece, the four sensors can measure the distance to the workpiece. The normal angle between the pressure foot and the workpiece can be calculated using the data from the four sensors. The formula for calculating the included normal angle in step S3 is: Where α is the angle in the X direction, β is the angle in the Y direction, l is the distance between two symmetrical ranging sensors, s1, s2, s3, and s4 represent the values ​​of the four ranging sensor readings after horizontal linearization, and θ represents the tilt angle of the ranging sensor. The calculation of the deviation between the contact position of the pressure foot and the workpiece and the workpiece hole-making position in the tool feed direction in step S4 is divided into the following four categories: a. When the workpiece surface is a spherical convex surface, the correction amount for the tool feed depth is: b. When the workpiece surface is a concave surface similar to a sphere, the correction amount for the tool feed depth is: c. When the workpiece surface is a cylindrical convex surface, the pressure foot detection error is 0, and the correction amount for the tool feed depth is: d. When the workpiece surface is a cylindrical concave surface, the tool feed depth correction is: Where r ph_in The radius r represents the inner circle radius of the pressure foot end face. ph_out The radius r represents the outer circle radius of the pressure foot end face. hl This represents the radius of the countersink hole, where R is the workpiece radius of curvature. In step S6, a high-precision grating ruler is used on the clamping shaft to achieve high-precision detection of the workpiece deformation, and the overall accuracy of the clamping shaft displacement detection is controlled within 0.005mm.

Images