Method for measuring probe angle using three-dimensional coordinate measuring machine

Abstract

The present invention discloses a method for measuring the angle of a probe of a three-dimensional coordinate measuring machine, belonging to the technical field of three-dimensional coordinate measuring machines, comprising: measuring the pitch angle of the probe: obtaining the center point O of the Z axis; when the probe swings during the process of measuring a workpiece, obtaining the center point B of the probe at this time; 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; obtaining the straight-line distance S1 between point O and point B, obtaining the distance H1 between point O and point C, obtaining the distance L1 between point B and point C, and using inverse trigonometric functions to determine the angle θ between straight line S1 and straight line H1. The present invention collects the probe signal of the three-dimensional coordinate measuring machine in real time, and the signal from the edge sensor of the turntable in real time. By collecting the probe signal and the sensor signal, the position relationship is determined by using the three-point plane, and a related calculation method is constructed to obtain the rotation angle and the pitch angle, which is conducive to improving the measurement accuracy of the workpiece.

Description

Technical Field

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

[0002] As a quality control method, three-dimensional coordinate measuring machine has the advantages of high detection accuracy, high degree of automation and easy operation, and is widely used.

[0003] When using a contact-type three-dimensional coordinate measuring machine to inspect workpieces with complex surfaces, the measurement path planning is complex and the measurement efficiency is low. At the same time, it is difficult to accurately estimate the actual contact point between the stylus and the surface, which seriously affects the measurement accuracy.

[0004] Therefore, controlling the position of the probe is conducive to improving 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 using a three-dimensional coordinate measuring machine, the method comprising:

[0006] Measurement of probe pitch angle:

[0007] S1, obtain point O, which is the center point of the Z axis;

[0008] 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;

[0009] The acquisition of the O point is determined by acquiring the signal of the central sensor;

[0010] S2, when the probe swings during the measurement of the workpiece, obtain point B at this time, said point B is the center point of the probe, and the acquisition of said point B is determined by the sensor signal on the probe

[0011] S3, obtaining a perpendicular line between point B and the center line of the Z axis, and recording the intersection of the perpendicular line and the center line of the Z axis as point C;

[0012] 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;

[0013] 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;

[0014] 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 inverse trigonometric functions to determine the angle θ between line S1 and line H1;

[0015] Measurement of probe rotation angle:

[0016] A1, any position on the edge of the turntable in its initial state is point D;

[0017] A2: When the turntable rotates, the probe rotates accordingly. When the turntable stops rotating, the position of point D is obtained as point E.

[0018] A3, obtain the 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;

[0019] 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.

[0020] Furthermore, the angle θ=arctan L1 / H1.

[0021] Furthermore, θ1=arccos((a12+b12-c12) / (2a1b1)).

[0022] Beneficial effects of the present invention:

[0023] The present invention collects the probe signals of a three-dimensional coordinate measuring machine in real time, and collects the signals of the edge sensor of the turntable in real time. By collecting the probe signals and sensor signals, the position relationship is determined by using three points to form a plane, and a related calculation method is constructed to obtain the rotation angle and pitch angle, thereby improving the measurement accuracy of the workpiece under the premise of ensuring the normal detection of the three-dimensional coordinate measuring machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 is a flow chart of pitch angle measurement according to an embodiment of the present invention;

[0026] Figure 2 4 is a flowchart of the rotation angle measurement according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, 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 intended to limit the present invention.

[0028] It should be noted that the invention of this scheme lies in that by selecting a center point as the base point, then obtaining the initial position point of the probe and the turntable, and obtaining the position point after the movement of the probe and the turntable, a plane is established through three points, and the pitch angle and rotation angle are determined using trigonometric functions.

[0029] See also Figures 1 to 2 , the method of measuring the probe angle of the three-dimensional coordinate measuring machine includes:

[0030] Measurement of probe pitch angle:

[0031] S1, obtaining point O, where point O is the center point of the Z axis, setting a center sensor at point O, then connecting the center sensor to an external computer for communication, sending a first signal to the computer via the center sensor, and determining the position of point O after the computer receives the first signal;

[0032] S2, when the probe swings on the measuring element, the computer receives a second signal sent by the sensor on the probe, and the computer determines the center point of the probe based on the second signal, wherein the center point of the probe is point B;

[0033] S3, the computer obtains a point C where the second signal intersects the first signal perpendicularly on the Z axis; wherein the first signal is the center sensor signal in the Z axis direction, and the second signal is the swing signal in the Y axis direction;

[0034] S4, the computer obtains the straight-line distance S1 between point O and point B, obtains the distance H1 between point O and point C, obtains the distance L1 between point B and point C, and uses the inverse trigonometric function θ = arctanL1 / H1 to determine the angle θ between line S1 and line H1;

[0035] Measurement of probe rotation angle:

[0036] A1. An edge sensor is provided at any position on the edge of the turntable. The edge sensor is communicatively connected to a computer. When the turntable is not rotating, the edge sensor sends a third signal to the computer at its initial position, and the center sensor sends a fourth signal to the computer. The sending point of the third signal is point D.

[0037] A2: When the turntable rotates, the probe rotates accordingly. During this process, the edge sensor and the center sensor exchange signals with the computer in real time. When the turntable stops rotating, the edge sensor sends a fifth signal to the computer. The sending point of the fifth signal is point E.

[0038] A3, the computer obtains the vertical intersection of the fourth signal and the fifth signal on the Z axis as point A;

[0039] A4. The computer obtains the straight-line distance a1 between point D and point A, the distance b1 between point E and point A, and the distance c1 between point D and point E. Using the triangle cosine theorem, θ1 = arccos((a12 + b12 - c12) / (2a1b1)), determine the angle θ1 between AD and AE.

[0040] 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 center sensor signal.

[0041] 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.

[0042] An edge sensor is provided at any position on the edge of the turntable, and the edge sensor is communicatively connected to a computer; acquisition of the points D and E is determined by signals from the edge sensors, and acquisition of the point A is determined by signals from the center sensor and the edge sensors.

[0043] 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.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for measuring the angle of a probe using a coordinate measuring machine, characterized in that: include: Measurement of probe pitch angle: S1, obtain point O, which is the center point of the Z axis; 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 central sensor; S2, when the probe swings during the measurement of the workpiece, obtaining point B at this time, wherein point B is the center point of the probe and is determined by a sensor signal on the probe; S3, obtaining a perpendicular line between point B and the center line of the Z axis, and recording the intersection of the perpendicular line and the center line of the Z axis as point C; 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; 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; 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 inverse trigonometric functions to determine the angle θ between line S1 and line H1; Measurement of probe rotation angle: A1, any position on the edge of the turntable in its 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; An edge sensor is provided at any position on the edge of the turntable, and the edge sensor is in communication with a computer; acquisition of the points D and E is determined by signals from the edge sensors, and acquisition of the point A is determined by signals from the center sensor and the edge sensors; 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.

2. The method for measuring the probe angle of a coordinate measuring machine according to claim 1, characterized in that: in, The angle θ=arctan L1 / H1.

3. The method for measuring the angle of a probe of a three-dimensional coordinate measuring machine according to claim 1, characterized in that: in, θ1=arccos((a1 2 +b1 2 -c1 2 ) / (2a1b1))。

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