Measuring equipment and measuring method

A measuring equipment is provided. The equipment includes: a multi-axial actuated device; at least one sensor disposed on the multi-axial actuated device to adjust the orientation of the at least one sensor by the multi-axial actuated device, wherein scanning constraints of the sensor include a movable range of the at least one sensor, a scanning range of the at least one sensor and a scanning dead space of the at least one sensor for the contour of an object to be tested; a rotating device configured to rotate the object; and a processing device configured to obtain information relating to an optimal scanning orientation of the sensor based on the scanning constraints, and configured to control the multi-axial actuated device to adjust the at least one sensor.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on, and claims priority from, Taiwan Application Serial Number 105139436, filed on Nov. 30, 2016, the disclosure of which is hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The disclosure relates to a measuring equipment and a measuring method.

BACKGROUND

With the vigorous development of Computer Numerical Control (CNC), machining accuracy is continuously improved and widely applied to precision machine industries. However, with an aim of quality consistency for machining products, inspecting rules of quality management accuracy need to be passed. Currently, some products are inspected manually; however, manual inspection not only costs time but also has limitations for measurement accuracy. Thus, digital automatic inspection technics is gradually imported into markets.

Among nowadays inspections of quality management, according to needs of the products, plural types of inspected items can be determined, for example, inspected items of the vehicle wheel may include central hub, diameter of the aluminum wheel, Pitch Circle Diameter (PCD), Degree of deflection, flatness, position, thickness of the protruding edge, and so on, wherein some of the aforesaid items are classified as Dimensional Tolerances which can be inspected directly. However, some other items are classified as Geometric Tolerances, such as position, PCD and so on, usually need to be adaptability measured and ensured by manually comparison through tools, for example, a Micrometer.

However, if the traditional manual inspection for quality control is conducted in the automated production line, not only the detection accuracy is limited, but also time cost is increased, especially in precision machine production.

Accordingly, adoption of the automatic inspecting system in the automated production line is necessary for improving speeds of product quality management, so as for increasing the whole producing efficiency.

SUMMARY

According to an embodiment of the present disclosure, a measuring equipment is provided. The measuring equipment includes a multi-axial actuated device, at least one sensor, a rotating device and a processing device. The sensor is disposed on the multi-axial actuated and configured to scan an object to be tested, wherein scanning constraints of the at least one sensor include a movable range of the at least one sensor, a scanning range of the at least one sensor or a scanning dead space of the at least one sensor for a contour of the object. The rotating device is configured to rotate the object. The processing device is configured to obtain information relating to an optimal scanning orientation of the at least one sensor based on the scanning constraints, and configured to control the multi-axial actuated device to adjust the at least one sensor.

According to an embodiment of the present disclosure, a measuring method is provided. The method comprises fixing an object to be tested at a scanning region of a measuring equipment; synchronously rotating and scanning the object by at least one sensor of the measuring equipment for obtaining information of an object coordinate system of the object, wherein scanning constraints of the sensor include a movable range of the at least one sensor, a scanning range of the sensor and a scanning dead space of the at least one sensor for a contour of the object; constructing, by a processing device, the object coordinate system according to the obtained information of the object coordinate system; calculating, by the processing device, information relating to an optimal scanning orientation of the at least one sensor, including: associating the object coordinate system of the object to a base coordinate system, wherein the base coordinate system is determined according to a configuration of the measuring equipment; aligning the object coordinate system with a Computer-aided design (CAD) model coordinate system of the object, wherein the CAD model coordinate system is constructed in the processing device; and calculating a scanning position and a scanning angle of the at least one sensor in the CAD model coordinate system for adjusting a scanning position and a scanning angle of the at least one sensor in the base coordinate system; adjusting, based on the information relating to an optimal scanning orientation, the sensor and then scanning a contour of the object by the at least one sensor; and transforming, by the processing device, information of the contour of the object from the base coordinate system to the object coordinate system.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG. 1is a perspective view of a measuring equipment1according to a first embodiment of the disclosure.

InFIG. 1, the measuring equipment1may include a rotating device10, a multi-axial actuated device11, sensors12aand12b, and a processing device13.

The rotating device10may be disposed on a production machine such as on a scanning region of an inline production machine (for example, a fixing stage14), and the rotating device10is configured to rotate an object9to be tested (for example, a steel wheel). The rotating device10may be a seat support for disposing the object9thereon.

In the embodiment, the rotating device10may include a rotating shaft, and a rotational axis of the rotating shaft may be substantially parallel to an axial direction (for example, the Z-axial direction as shown inFIG. 1) perpendicular to a loading surface14aof the fixing stage14, so that the object9may be rotated with respect to the axial direction.

In addition, the rotating device10may be linearly moved upward or downward (for example, the positive or negative direction of the Z-axis) by an elevating mechanism, and the rotating device10may have a fixing part15, as shown inFIG. 2A, to fix the object9, so that the object9may be rotated with respect to the axial direction (for example, the Z-axial direction).

And, the fixing part15may include plural of fixtures150(as shown inFIG. 2B) and a motor (not shown) configured to drive those fixtures150. For example, the fixtures150may be the fixtures of pistol grip types which can be driven and expand outward (for example, as shown inFIG. 2C) to reach the inner wall of a hole90of the object9(for example, a hole located at a bottom-center or any other position of a steel wheel) for fixing the object9. The fixtures150may also be moved based on a size of the object9so as to be capable of fixing the objects9with different sizes.

Consequently, when the inspected object9is located at the fixing stage14corresponding to the rotating device10, the rotating device10is lifted up and then the fixtures150are driven by the motor of the fixing part15to fix the object9(for example, as shown inFIG. 2C) for inspection. After end of the inspection, the fixtures150are driven by the motor to release the object9and then the rotating device10is turned down for moving the object9to next workstation.

There are many kinds of objects that can be considered. In embodiments of the disclosure, an object is considered based on the rotation motion during measurement. In one embodiment, according to the rotation of the fixing mechanics during measurement, the object9with reference surface or reference axis may be chosen for the inspection. For example, the object9may be a workpiece having an axial-symmetry structure, the workpiece may be typically an object having central hub such as a bearing, a brake disc, or a round wheel, but the scope of the disclosure is not limited thereto.

In embodiments of the disclosure, the multi-axial actuated device11may be installed on the fixing stage14, and be around the rotating device10during measurement.

In the embodiment ofFIG. 1, the multi-axial actuated device11may have a bridge-type and include a supporting frame110and a shifting assembler16disposed on the supporting frame110, wherein the supporting frame110may be movably detached to the fixing stage14so that the shifting assembler16may be at top and one side (left or right side) of the rotating device10according to the movement of the supporting frame110.

In addition, the supporting frame110may be linearly moved along forward or backward direction of the fixing stage14(for example, the X-axial direction shown inFIG. 1) by, for example, utilizing rail structures (not shown) disposed at left and right sides of the fixing stage14.

And, as shown inFIG. 1, the shifting assembler16may include a first robotic arm17and a second robotic arm18, wherein the first robotic arm17may be disposed at top of the rotating device10and the second robotic arm18may be disposed at left side of the rotating device10.

Specifically, as shown inFIG. 2D, the first robotic arm17may include two linear rails17a,17band a first rotator17c, wherein the linear rails17a,17bmay be arranged along different axial directions (for example, the Y-axial rail17aand the Z-axial rail17b), and the Y-axial rail17amay be bridged over two pillars110aof the supporting frame110, the Z-axial rail17bmay be disposed on the Y-axial rail17aand configure to be shuttled left and right in the opposite direction of the supporting frame110and be stretched or retreated up and down in the opposite direction of the Y-axial rail17a. The first rotator17cmay be disposed at the bottom-end of the Z-axial rail17band axially oscillated around the Y-axis (such as the back and forth oscillation of the arrow R).

And, as shown inFIG. 2E, the second robotic arm18may include two linear rails18a,18band a second rotator18c, wherein the linear rails18a,18bmay be arranged along different axial direction (for example, the Y-axial rail18aand the Z-axial rail18b), and the Z-axial rail18bmay be disposed on one of the pillars110aof the supporting frame110, the Y-axial rail18amay be disposed on the Z-axial rail18band configure to be shuttled up and down in the opposite direction of the pillar110aand stretched or retreated left and right in the opposite direction of the Z-axial rail18b. The second rotator18cmay be disposed at the left-end of the Y-axial rail18aand axially oscillated around the X-axis (such as the left and right oscillation of the arrow C).

Thence in measuring, the supporting frame110may firstly be moved for adjusting positions of the pillars110a, to have the first robotic arm17being located at top of the rotating device10, and then the first and second robotic arms17and18are actuated.

The aforementioned sensors12aand12bmay respectively be disposed on the first and second rotators17cand18cof the multi-axial actuated device11, so that the first and second robotic arms17and18can be actuated to adjust the orientations of the sensors12aand12bfor sensing, and hence the object9fixed on the rotating device10can be measured effectively by the sensors12aand12b. In other words, with the first and second robotic arms17and18of the shifting assembler16, the multi-axial actuated device11may adjust the orientations of the sensors.

In the embodiment, the sensors12aand12bmay be optical sensors, such as laser-type rangefinder, but the scope of the disclosure is not limited thereto.

And, scanning constraints of the sensors12aand12bmay include a movable range of the sensor, a scanning range of the sensor or a scanning dead space of the sensor for a contour of the object. Specifically, the sensor12aor12bmay be an optical rangefinder for scanning an object to measure the geometric dimension of the object, but a scanning dead space (for example, as the dash line shown inFIG. 2G) of the sensor may be aroused due to a contour of the object9′; and the sensor12aor12bmay have intrinsic constraints in specifications, such as the range of a View Angle θ (for example, the limitation of an angle between an incident line of light-beam and a normal line of the scanned surface shown inFIG. 2F), the valid Depth of Field D (for example, the limitation of scanning depth), and so on. In addition, a movable range of the sensor12aor12bmay be restricted by the multi-axial actuating device11. Therefore, aforesaid constraints may need to be solved for obtaining more complete or valid measuring data of the object9from the measuring equipment1, for example, constraints of scanning dead space of the sensor due to the contour of the object9′ can be solved by adjusting orientations of the sensor12aor12b, as shown in FIG.2H).

Therefore, a movable range of the sensor12aor12bmay be determined according to the structural design of the multi-axial actuated device11, a scanning range of the sensor12aor12bmay be determined according to species of the sensor, and a scanning dead space of the sensor due to the contour of the object may be determined according to the structure such as the contour of the object9to be tested.

In addition, considering the random variations raised from the installation of the object9, the location and the posture of the sensor12aor12bmay be dynamically or adaptively adjusted when installing the object9to the measuring equipment1. And then, after fixing the object9, a contour of the object9can be measured by rotating the object9relative to the sensor12aor12b, so that dimensions of the object9can be obtained from the measuring and some specific dynamic features, such as runout of the object9, may also be obtained from the measuring.

The aforesaid processing device13is configured to deal with the scanning constraints of the sensor12aor12b, to have the sensor12aor12bbeing adjusted to an optimal direction or posture by the multi-axial actuated device11.

In the embodiment, the processing device13may be a control computer or a portable computer. The processing device13may include a controller, an Arithmetic Unit (AU), a processor or known hardware.

In addition, the processing device13may be wirely or wirelessly coupled to the sensors12aand12bfor receiving information, wherein the information may include information of movable ranges of the sensors12aand12b, scanning ranges of the sensors12aand12bor a scanning dead space relating to the contour of the object9.

And, the processing device13may be electrically coupled to the multi-axial actuated device11for controlling movement of the multi-axial actuated device11.

FIGS. 3A and 3Bare perspective views of a measuring equipment2according to a second embodiment of the disclosure. In the embodiment, the production stage is apparently different from the fixing stage14of the first embodiment, and other structures of the equipment2and the equipment1of the first embodiment may be same or similar.

As shown inFIG. 3A, the production stage may be a transportation stage24, for example a conveyor, and a transportation belt of the transportation stage24may be constituted of plural flattened roll bars24aas a roller conveyor.

In the embodiment, the transportation stage24has an opening240at the location corresponding to the rotating device10, as shown inFIG. 3B, so that the rotating device10can be elevated through the opening240by an elevator20for fixing the object9.

In an embodiment, the transportation belt of the transportation stage24may be constituted of an isolation belt with well ductility.

FIGS. 4A and 4Bare perspective views of a measuring equipment3according to a third embodiment of the disclosure. In the embodiment, the rotating device is apparently different from the one of the second embodiment, and other structures of the equipment3and the equipment2of the second embodiment may be same or similar.

As shown inFIGS. 4A and 4B, the rotating device30includes standing bars30acapable of being laterally moved, so that the standing bars30acan withstand the object9, thereby fixing object9when the object9is in the scanning region.

In the embodiment, four standing bars30aof the rotating device30are arranged so that they have spaces between them, and a rectangular contour is thus formed to facilitate fixing the object9, but the scope of the disclosure is not limited thereto.

And, the object9may be driven to rotate through the self-rotating of the standing bar30aaround a vertical axis of the standing bar30a, wherein the vertical axis of the standing bar30amay be in an up-and-down direction or the Z-axial direction shown inFIG. 4A. Understandingly, the mutual motion between the standing bars30aand the object9is same as the rotation of the transform, and, therefore, the mechanism for the mutual rotating motion between them may be embodied through gear, friction or the likes.

While only two sensors12aand12bare illustrated in aforesaid three embodiments, it will be understood those sensors12aand12bmay be determined through working with the configurations of the multi-axial actuated devices11of the equipment1,2and3, respectively. Therefore, a measuring equipment of the disclosure may include a single sensor or at least three sensors capable of scanning top or side of the object9, but the scope of the disclosure is not limited thereto.

FIG. 5is a schematic flow diagram of a measuring method according to an embodiment of the disclosure. In the embodiment, the measuring method may be embodied by the aforesaid equipment1,2or3.

As shown inFIG. 6A, before the three steps S1to S3of analyzing an optimal scanning orientation of the sensor, constructing an object coordinate system (Xo, Yo, Zo) of the object9to be tested is performed, including: obtaining an object coordinate system (Xo, Yo, Zo) of the-object9after the object9is fixed in a scanning region (for example, fixed on the rotating device10or30). In the embodiment, the supporting frame110and the first robotic arm17are utilized for moving the sensor12ato the top region of the rotational axis (for example, the region above the center of the object9as shown inFIG. 2D) of the rotating device10or30, and then rotating the object9by the rotating device10or30and scanning the object9, synchronously, for measuring a reference surface or a reference axis so as to construct the object coordinate system (Xo, Yo, Zo) in the processing device13.

Next, the optimal scanning orientation of the sensor12bis analyzed for the second robotic arm18, as the steps S1to S3shown inFIG. 5, exemplary details are disclosed in the following.

Step S1: Associating the object coordinate system (Xo, Yo, Zo) to a base coordinate system (Xm, Ym, Zm), as shown inFIG. 6A, wherein the base coordinate system (Xm, Ym, Zm) may be determined according to the configuration of the equipment1,2or3. In the embodiment, random derivations may arise at times as fixing the object9to the equipment1,2or3, and hence a transformation relation between the object coordinate system (Xo, Yo, Zo) and the base coordinate system (Xm, Ym, Zm) may need to be constructed.

Step S2: Aligning the object coordinate system (Xo, Yo, Zo) with a CAD model coordinate system (Xc, Yc, Zc) of the object9, as shown inFIG. 6B, for obtaining a transformation relation between the object coordinate system (Xo, Yo, Zo) and the CAD model coordinate system (Xc, Yc, Zc). In the embodiment, the CAD (Computer-aided design) model coordinate system (Xc, Yc, Zc) may be stored in the processing device13.

Step S3: Calculating the scanning position and the scanning angle of the sensor12bin the CAD model coordinate system (Xc, Yc, Zc), then transforming the scanning position and the scanning angle to the base coordinate system (Xm, Ym, Zm), so as to adjust orientations (for example, scanning position and the scanning angle) of the sensor12bfor scanning.

In the embodiment, the optimal scanning orientation of the sensor12bmay be obtained by adopting probabilistic technique to analyzing a curve surface of the object9, wherein the probabilistic technique may solve a combinatorial optimization problem. For example, in Step S3, an optimization algorithm, such as Genetic Algorithm (GA), may be performed to calculate the scanning position and the scanning angle of the sensor12bin the CAD model coordinate system. In an embodiment, the optimization algorithm may be Simulated annealing (SA), Particle Swarm Optimization (PSO), and so on, but the scope of the disclosure is not limited thereto.

In addition, as shown inFIG. 7, exemplary details of performing Genetic Algorithm (GA) may include the following.

Initialization: Assigning six genes to each chromosome, wherein three of the six genes are assigned as parameters of scanning position and the other three of the six genes are assigned as parameters of scanning angle, and defining ranges of each gene (for example, scanning ranges of the sensor12aand12b).

Evaluation: Calculating fitness values (for example, scanning ranges effectively covering the curve surface of the object) of all the chromosomes (for example, the scanning positions and the scanning angles) in the group of a generation.

Termination Criteria: Judging whether those fitness values of the whole chromosomes are good or bad, and if an ending threshold is passed then calculating an average of all the chromosome and assigning the average as the optimal solutions, otherwise entering processes such as Selection, Reproduction, Crossover, Mutation, and so on for re-Evaluation.

And, the sensor12bhas following constraints: a movable range of the sensor12b; a scanning dead space relating to the contour of the object; and constraints of scanning range, such as View Angle θ of the sensor12b, Depth of Field D of the sensor12b, and so on. Therefore, utilizing the Optimization Algorithms to calculate an optimal scanning position and an optimal scanning angle of the sensor12bwhere the sensor12bmay effectively scan the curve surface of the object9, so that meaningless scan data and measurement time may be effectively reduced.

After Step S3, as shown inFIG. 5, a second rotational scanning is proceeded with adjusting, by the second robotic arm18, the sensor12bto an optimal or better scanning orientation, as shown inFIG. 6C(a scanning range P of the sensor12bcan cover a projected area A of the curve surface of the object9), and then the rotating device10or30is actuated so that the sensors12aand12bcan synchronously scan the object9, and the processing device13is utilized to process the scanned contour data from the sensors12aand12band transform coordinates of the scanned contour data from the base coordinate system (Xm, Ym, Zm) to the object coordinate system (Xo, Yo, Zo).

And then, the processing device13obtains and stores the transformed scanned contour data for calculating feature tolerances or feature accuracy of the object9.

Accordingly, the aforesaid exemplary method may be executed with the measuring equipment1,2or3of the present disclosed embodiments; utilize the rotating device10or30and the multi-axial actuated device11for overcoming scanning constraints of the sensors12aand12b, so that an user may fix the inspected object9on the rotating device10or30; utilize the sensor12aof the first robotic arm17for scanning the object9and obtaining information of reference surface or reference axis of the inspected object9; calculate the object coordinate system (Xo, Yo, Zo) based on the information of the reference surface or the reference axis and then obtain a transformation relation between the object coordinate system (Xo, Yo, Zo) and the base coordinate system (Xm, Ym, Zm) of the measuring equipment. After that, the object coordinate system (Xo, Yo, Zo) may be aligned with a CAD model coordinate system (Xc, Yc, Zc) of the object9for calculating an optimal measuring angle of the object9in the CAD model coordinate. After the optimal measuring angle of the object9in the CAD model coordinate system is transformed, the sensor12b, disposed on second robotic arm18, may be automatically adjusted to an optimal scanning position and an optimal scanning angle of the sensor12bin the base coordinate system (Xm, Ym, Zm), and then the sensors12aand12bcan scan the object9synchronously for preventing invalid measurement.

In addition, in the embodiments, based on the pre-known CAD model of the object9, a better or optimal scanning location and a better or optimal scanning posture of the sensor12bmay be calculated in order to overcome scanning constraints of the sensor12b.

And, it should be understood that the disclosed method is not limited to be applied with the embodied measuring equipment1,2, or3of the present disclosure.

According the aforementioned embodiments, the disclosed method and the equipment may utilize the rotating device and the multi-axial actuated device for overcoming scanning constraints of the sensors, so as to prevent or lower invalid measurement, reduce time for repeating adjustment and working time of machine operations, and reduce mismeasurements arisen from movements.

In summary, the method and the equipment disclosed in aforementioned embodiments may be applied on Automated Production Line, for example, especially on Fine Machining Production, so as to improve measurement accuracy and save production time and efforts.