Method for measuring angle of measuring head by three-coordinate measuring machine

Abstract

The invention discloses a method for measuring the angle of a measuring head by a three-coordinate measuring machine, which belongs to the technical field of three-coordinate measuring machines and comprises the following steps of: measuring the pitch angle of the measuring head: acquiring a central point O of a Z axis; when the measuring head swings in the workpiece measuring process, a measuring head center point B at the moment is obtained; obtaining a vertical line of the point B and the Z-axis center line, and recording an intersection point of the vertical line and the Z-axis center line as a point C; and acquiring a linear distance S1 between the point O and the point B, acquiring a distance H1 between the point O and the point C, acquiring a distance L1 between the point B and the point C, and determining an included angle theta between the linear S1 and the linear H1 by using an inverse trigonometric function. According to the method, the rotation angle and the pitch angle can be obtained by collecting the measuring head signal of the three-coordinate measuring machine in real time, collecting the signal of the edge sensor on the rotary table in real time, collecting the measuring head signal and the sensor signal, determining the position relation by utilizing three points to form a plane, and constructing a related calculation mode, so that the measurement precision of a workpiece can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coordinate measuring machines, and particularly relates to a method for measuring the angle of a probe of a coordinate measuring machine. Background Art

[0002] As a quality control means, the coordinate measuring machine has the advantages of high detection accuracy, high automation degree, convenient operation, etc., and is widely used.

[0003] When using a contact coordinate measuring machine to detect workpieces with complex curved surfaces, the measurement path planning is complex, the measurement efficiency is low, and it is difficult to accurately estimate the true contact point between the probe and the curved surface, seriously affecting the measurement accuracy.

[0004] Therefore, controlling the position of the probe is beneficial to improving the measurement accuracy. Summary of the Invention

[0005] In view of the above problems, the present invention provides a method for measuring the angle of a probe of a coordinate measuring machine, and the method includes: Measurement of the pitch angle of the probe: S1. Obtain the center point O of the Z-axis; S2. When the probe swings during the measurement of the workpiece, obtain the center point B of the probe at this time; S3. Obtain the perpendicular line from point B to the center line of the Z-axis, and the intersection point of the perpendicular line and the center line of the Z-axis is denoted as point C; S4. Obtain the linear distance S between point O and point B 1 , obtain the distance H between point O and point C 1 , obtain the distance L between point B and point C 1 , use the inverse trigonometric function to determine the included angle θ between the straight line S 1 and the straight line H 1 ; Measurement of the rotation angle of the probe: A1. Take any position on the edge of the rotary table in the initial state as point D; A2. When the rotary table rotates and the probe rotates accordingly, when the rotary table stops rotating, obtain the position where point D is located at this time as point E; A3. Obtain the perpendicular line from point E to the center line of the Z-axis, and the intersection point of the perpendicular line and the center line of the Z-axis is denoted as point A; A4. Obtain the linear distance a between point D and point A 1 , obtain the distance b between point E and point A 1 , obtain the distance c between point D and point E 1 , use the cosine theorem of a triangle to determine the included angle θ between AD and AE 1 .

[0006] Furthermore, a central sensor is provided at point O, the central sensor is communicatively connected to a computer, a sensor is provided on the probe head, and the sensor is communicatively connected to the computer; The acquisition of point O is determined by acquiring the signal of the central sensor, and the acquisition of point B is determined by the sensor signal on the probe head.

[0007] Furthermore, the acquisition of point B is determined by the swing signal sent by the sensor on the probe head, and the acquisition of point C is determined by the swing signal and the central sensor signal.

[0008] Furthermore, point C is the intersection of the central sensor signal in the Z-axis direction and the swing signal in the Y-axis direction.

[0009] Furthermore, where the included angle θ = arctanL 1 / H 1 .

[0010] Furthermore, an edge sensor is provided at any position on the edge of the rotary table, and the edge sensor is communicatively connected to the computer; the acquisition of points D and E is determined by the signal of the edge sensor, and the acquisition of point A is determined by the signal of the central sensor and the signal of the edge sensor.

[0011] Furthermore, the acquisition of point D is determined by the initial signal of the initial position of the edge sensor, the acquisition of point E is determined by the rotation signal of the edge sensor after the rotary table rotates, and the acquisition of point A is the intersection of the central sensor signal in the Z-axis direction and the rotation signal of point E in the Y-axis direction Furthermore, where θ 1 = arccos((a 1 ² + b 1 ² - c 1 ²) / (2a 1 b 1 ))

[0012] Advantages of the present invention: By collecting the probe head signal of the coordinate measuring machine in real time and the signal on the edge sensor on the rotary table in real time, through the collection of the probe head signal and the sensor signal, using the relationship of three points forming a plane to determine the position relationship and constructing relevant calculation methods, the rotation angle and pitch angle can be obtained, so as to improve the measurement accuracy of the workpiece on the premise of ensuring the normal detection of the coordinate measuring machine. Description of the Drawings

[0013] The accompanying drawings, which form a part of this application, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0014] Figure 1 is the pitch angle measurement flowchart of an embodiment of the present invention; Figure 2 is the swing angle measurement flowchart of an embodiment of the present invention. Detailed implementation manners

[0015] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] It should be noted that the inventive point of this solution lies in that by selecting a center point as a reference point, then obtaining the points of the initial positions of the probe and the rotary table, and obtaining the points of the positions of the probe and the rotary table after movement, a plane is established through the three points, and the pitch angle and the swing angle are determined using trigonometric functions.

[0017] See Figures 1 to 2 , the method for a coordinate measuring machine to measure the angle of a probe, including: Measurement of the pitch angle of the probe: S1. Set a central sensor at the center point O on the Z axis, then communicatively connect the central sensor with an external computer, send a first signal to the computer through the central sensor, and after receiving the first signal, the computer determines the position of point O; S2. When the probe swings on the measuring element, the computer receives a second signal sent by a sensor set on the probe, and the computer determines the center point B of the probe through the second signal; S3. The computer obtains the perpendicular intersection point C of the second signal and the first signal on the Z axis; wherein the first signal is the signal of the central sensor in the Z axis direction, and the second signal is the swing signal in the Y axis direction; S4. The computer obtains the straight-line distance S1 between point O and point B, obtains the distance H between point O and point C 1 , obtains the distance L between point B and point C 1 , and uses the inverse trigonometric function θ = arctanL 1 / H 1 to determine the included angle θ between the straight line S 1 and the straight line H 1 ; Measurement of the swing angle of the probe: A1. Set an edge sensor at any position on the edge of the turntable, connect the edge sensor to the computer for communication. When the turntable is not rotating, the edge sensor sends a third signal to the computer at the initial position, and the center sensor sends a fourth signal to the computer. Here, the signal sending point of the third signal is point D. A2. When the turntable rotates, the probe rotates accordingly. During this process, both the edge sensor and the center sensor interact with the computer in real-time for signal exchange. When the turntable stops rotating, the edge sensor sends a fifth signal to the computer, and the signal sending point of the fifth signal is point E. A3. The computer obtains the perpendicular intersection point of the fourth signal on the Z-axis and the fifth signal as point A. A4. The computer obtains the straight-line distance a between point D and point A 1 , obtains the distance b between point E and point A 1 , obtains the distance c between point D and point E 1 , uses the cosine theorem of a triangle θ1 = arccos((a 1 ² + b 1 ² - c 1 ²) / (2a 1 b 1 )) to determine the included angle θ between AD and AE 1 .

[0018] Among them, the acquisition of point B is determined by the swing signal sent by the sensor on the probe, and the acquisition of point C is determined by the swing signal and the signal of the center sensor.

[0019] Point C is the intersection point of the center sensor signal in the Z-axis direction and the swing signal in the Y-axis direction.

[0020] An edge sensor is provided at any position on the edge of the turntable, and the edge sensor is connected to the computer for communication; the acquisition of point D and point E is determined by the signal of the edge sensor, and the acquisition of point A is determined by the signal of the center sensor and the signal of the edge sensor.

[0021] The acquisition of point D is determined by the initial signal at the initial position of the edge sensor, the acquisition of point E is determined by the rotation signal of the edge sensor after the turntable rotates, and the acquisition of point A is the intersection point of the center sensor signal in the Z-axis direction and the rotation signal of point E in the Y-axis direction.

[0022] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for measuring the angle of a probe using a three-dimensional coordinate measuring machine, characterized in that: include: Measurement of probe pitch angle: S1, obtain the center point O of the Z axis; S2, when the probe swings during the process of measuring the workpiece, the center point B of the probe is obtained; S3, obtaining a perpendicular line between point B and the center line of the Z axis, and the intersection of the perpendicular line and the center line of the Z axis is recorded as point C; S4, obtain the straight-line distance S1 between point O and point B, obtain the distance H1 between point O and point C, obtain the distance L1 between point B and point C, and use the inverse trigonometric function to determine the angle θ between the straight line S1 and the straight line H1; Measurement of probe rotation angle: A1, any position on the edge of the turntable in the initial state is point D; A2, when the turntable rotates, the probe rotates accordingly. When the turntable stops rotating, the position of point D is obtained as point E; A3, obtain a perpendicular line between point E and the center line of the Z axis, and the intersection of the perpendicular line and the center line of the Z axis is recorded as point A; A4, obtain the straight-line distance a1 between point D and point A, obtain the distance b1 between point E and point A, obtain the distance c1 between point D and point E, and use the triangle cosine theorem to determine the angle θ1 between AD and AE.

2. The method for measuring the angle of a probe by a three-dimensional coordinate measuring machine according to claim 1, characterized in that: A center sensor is provided at the O point, and the center sensor is connected to the computer for communication; a sensor is provided on the probe, and the sensor is connected to the computer for communication; The acquisition of the O point is determined by acquiring the signal of the center sensor, and the acquisition of the B point is determined by the sensor signal on the probe.

3. The method for measuring the angle of a probe by a three-dimensional coordinate measuring machine according to claim 2, characterized in that: The acquisition of the point B is determined by the swing signal sent by the sensor on the probe, and the acquisition of the point C is determined by the swing signal and the center sensor signal.

4. The method for measuring the angle of a probe by a three-dimensional coordinate measuring machine according to claim 3, characterized in that: The point C is the intersection of the center sensor signal in the Z-axis direction and the swing signal in the Y-axis direction.

5. The method for measuring the angle of a probe by a three-dimensional coordinate measuring machine according to claim 1, characterized in that: in, The angle θ=arctanL1 / H1.

6. The method for measuring the angle of a probe by a three-dimensional coordinate measuring machine according to claim 2, characterized in that: An edge sensor is provided at any position of the edge of the turntable, and the edge sensor is communicatively connected to a computer; the acquisition of the point D and the point E is determined by the signal of the edge sensor, and the acquisition of the point A is determined by the signal of the center sensor and the signal of the edge sensor.

7. The method for measuring the angle of a probe by a three-dimensional coordinate measuring machine according to claim 6, characterized in that: The acquisition of point D is determined by the initial signal of the initial position of the edge sensor, the acquisition of point E is determined by the rotation signal of the edge sensor after the turntable rotates, and the acquisition of point A is the intersection of the center sensor signal in the Z-axis direction and the rotation signal of point E in the Y-axis direction.

8. The method for measuring the angle of a probe by a three-dimensional coordinate measuring machine according to claim 1, characterized in that: in, θ1=arccos((a1²+b1²-c1²) / (2a1b1)).

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