Tool and method for measuring parallelism and angle of shank skeleton of vehicle crash dummy

Disclosed are a tool and a method for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy. The tool includes: a fixation seat, where a magnetic fastener is arranged on the fixation seat and configured to mount a shank U-shaped member; and a movement assembly that is configured to drive a measurement assembly to move, so as to change a relative position of a measurement end of the measurement assembly and the shank U-shaped member. The condition that the measurement assembly directly comes into contact with the shank U-shaped member, and damages a surface of the shank U-shaped member is avoided while making an entire measurement process more convenient.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Chinese Patent Application No. 202310847462.6, filed on Jul. 12, 2023 and entitled “Tool and Method for Measuring Parallelism and Angle of Shank Skeleton of Vehicle Crash Dummy”, the content of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to the technical field of vehicle safety crash tests, in particular to a tool and a method for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy.

BACKGROUND

A vehicle crash dummy is crucial to the development of vehicle safety performance as an essential tool in a vehicle crash test. An existing vehicle crash dummy has a complex skeleton structure, and includes a shank U-shaped member to be welded. The shank U-shaped member of the crash dummy has a special structure with splints at two sides to be welded to a base. However, parts are likely to deform during welding, and their tolerance accuracy will be affected accordingly. In addition, it is difficult to accurately measure geometric tolerances including an angle of the base and a parallelism of the splints at two sides of the U-shaped member efficiently. And a parallelism measurement surface is connected to a knee sensor, and an angle measurement surface is connected to a tibia sensor. As a result, parallelism and angle deviations are likely to lead to the unreliability of overall measurement data of the sensor of the crash dummy eventually and affect the accuracy of the vehicle crash test if not found in time.

At present, the U-shaped member is mainly measured in contact and non-contact manners. In the case of the contact manner, a surface of a workpiece is likely to be damaged since it directly comes into contact with a measurement tool, which makes it impossible to satisfy test requirements in terms of precision. When the non-contact manner is used, a measurement apparatus cannot be reasonably mounted due to size limitation of the U-shaped workpiece to be measured. In view of this, a tool and a method for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy are provided for solving the above problems.

SUMMARY

In order to solve the above defects or deficiencies in the prior art, a tool and a method for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy are to be provided to conveniently and timely measure the parallelism and the angle, improve the machining accuracy of the shank skeleton of the crash dummy and improve a yield.

In a first aspect, the present disclosure provides a tool for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy. The tool includes:a fixation seat, where a magnetic fastener is arranged on the fixation seat and configured to mount a shank U-shaped member; the shank U-shaped member includes a base and a first splint and a second splint that are arranged on the base, the magnetic fastener has a standard angle, and the base has a preset angle; and under the condition that the base is mounted on a surface of the fixation seat, a surface, far away from the fixation seat, of the base forms a prediction plane;a measurement assembly, where the measurement assembly is provided with a first measurement end and a second measurement end, measurement directions of the first measurement end and the second measurement end are perpendicular to each other, and the measurement direction of the first measurement end is perpendicular to a bottom surface of the magnetic fastener; anda movement assembly, where the movement assembly is arranged between the measurement assembly and the fixation seat, and the movement assembly is provided with a drive end that is connected to the measurement assembly and configured to drive the measurement assembly to move, so as to change relative positions of the first measurement end and the base corresponding thereto, and of the second measurement end and the first splint or the second splint corresponding thereto.

In a second aspect, the present disclosure provides a method for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy implemented based on the tool described above. The method includes:driving, by a movement assembly, a measurement assembly to move in a first direction and towards a side close to a fixation seat, measuring a real-time distance between a first measurement end and a prediction plane and outputting a first curve by the first measurement end, and measuring a real-time distance between a second measurement end and a first splint and outputting a second curve by the second measurement end, where the first direction and a bottom surface of the fixation seat are arranged in parallel;driving, by the movement assembly, the measurement assembly to move in a second direction and towards a side far away from a base, and simultaneously measuring a real-time distance between the second measurement end and the first splint and outputting a third curve by the second measurement end, where the second direction is perpendicular to the first direction;causing the measurement assembly to rotate clockwise by 180°, driving, by the movement assembly, the measurement assembly to move in the second direction and towards a side close to the base, and measuring a real-time distance between the second measurement end and a second splint and outputting a fourth curve by the second measurement end;driving, by the movement assembly, the measurement assembly to move in the first direction and towards a side far away from the fixation seat, and measuring a real-time distance between the second measurement end and the second splint and outputting a fifth curve by the second measurement end;obtaining an ideal datum plane;computing five parallelism errors according to the first curve, the second curve, the third curve, the fourth curve and the fifth curve by taking the ideal datum plane as a datum; anddetermining that a preset angle is equal to a standard angle and the first splint and the second splint are parallel to the ideal datum plane respectively when all parallelism errors fall within a parallelism tolerance interval.

To sum up, the present disclosure discloses a specific structure of a tool for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy. According to the present disclosure, the magnetic fastener is arranged on the fixation seat for mounting the shank U-shaped member. The shank U-shaped member includes the base and the first splint and the second splint that are arranged on the base, the magnetic fastener has the standard angle, and the base has the preset angle; and under the condition that the base is mounted on the surface of the fixation seat, the surface, far away from the fixation seat, of the base forms the prediction plane. The tool further includes: the measurement assembly, where the measurement assembly is provided with the first measurement end and the second measurement end, the measurement directions of the first measurement end and the second measurement end are perpendicular to each other, and the measurement direction of the first measurement end is perpendicular to the bottom surface of the magnetic fastener; and the movement assembly that is arranged between the measurement assembly and the fixation seat, where the movement assembly is provided with the drive end that is connected to the measurement assembly and configured to drive the measurement assembly to move, so as to change relative positions of the first measurement end and the base and of the second measurement end and the first splint or the second splint.

According to the present disclosure, through cooperation of the measurement assembly and the movement assembly, the first measurement end and the second measurement end may measure the real-time distance between the first measurement end and the corresponding prediction plane, and the real-time distance between the second measurement end and each of the first splint and the second splint respectively. The angle tolerance that is difficult to measure accurately is converted into the parallelism tolerance that is easy to measure, such that whether the angle tolerance satisfies standards is indirectly determined, that is, the angle of the base and the parallelisms of the two splints can be measured quickly, and the condition that the measurement assembly directly comes into contact with the shank U-shaped member, and damages the surface of the member is avoided while making an entire measurement process more convenient and rapid.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure will be further described in detail below with reference to accompanying drawings and in conjunction with examples. It can be understood that particular examples described herein are merely used to explain relevant disclosure, rather than limit the present disclosure. In addition, it should be further noted that merely the parts related to the present disclosure are shown in the accompanying drawings for the convenience of description.

It should be noted that examples in the present disclosure and features therein can be combined with one another if there is no conflict. The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with the examples.

The present disclosure provides a tool for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy. As shown inFIGS.2aand2b, the tool includes:a fixation seat1configured to mount a shank U-shaped member2, where the shank U-shaped member2includes a base3and a first splint4and a second splint5that are arranged on the base3. In this case, the first splint4and the second splint5are the same kind of splint, and are defined as the first splint4and the second splint5for the convenience of distinguishing a certain splint when a second measurement end measures a distance between the second measurement end and the certain splint, as shown inFIG.6a.

As shown inFIG.2a, the fixation seat1is a pedestal connected to a side, far away from a first drive member8, of a first guide rail6. A magnetic fastener17is arranged on the pedestal, and the magnetic fastener17is magnetic and may attract the base3, so as to facilitate mounting and fixation of the base3, as shown inFIG.3c. The magnetic fastener17has a standard angle α which may be 16°. The base3has a preset angle β. When the base3is mounted on a surface of the fixation seat1, a surface, far away from the fixation seat1, of the base3forms a prediction plane3-1. In this case, the prediction plane3-1refers to the surface of the base3that is relatively far away from the fixation seat1and may be measured by a first measurement end.

Specifically, as shown inFIGS.3aand3b, the magnetic fastener17includes:a first straight wall17-1, a second straight wall17-2and a third straight wall17-3that are connected in sequence, wherea first included angle is formed between the first straight wall17-1and the second straight wall17-2, the first included angle is 90°, and an opening of the first included angle faces the third straight wall17-3; anda second included angle is formed between the first straight wall17-1and the third straight wall17-3, the second included angle is the standard angle α, and an opening of the first included angle faces the second straight wall17-2.

The base3has a preset included angle, and the preset included angle is the preset angle β. In this case, the preset included angle of the base3is formed between a bottom surface of the base3and an upper surface of the base3for mounting the first splint4and the second splint5.

When the base3is mounted on the magnetic fastener17, an opening of the preset angle faces a second guide rail9, the bottom surface of the base3is in surface contact with the third straight wall17-3, and a surface, far away from the magnetic fastener17, of the base3forms the above prediction plane3-1. In addition, when the prediction plane3-1is parallel to an ideal datum plane and a bottom surface of the magnetic fastener17, the second included angle α and the preset angle β are a pair of alternate interior angles.

The tool further includes a measurement assembly01, where the measurement assembly is configured to measure a real-time distance between the measurement assembly and each of the prediction plane3-1, the first splint4or the second splint5, the measurement assembly01is provided with a first measurement end13-1and a second measurement end14-1, measurement directions of the first measurement end13-1and the second measurement end14-1are perpendicular to each other, and the measurement direction of the first measurement end13-1is perpendicular to the bottom surface of the magnetic fastener17; anda movement assembly02, where the movement assembly is arranged between the measurement assembly01and the fixation seat1, and the movement assembly02is provided with a drive end18that is connected to the measurement assembly01and configured to drive the measurement assembly01to move, so as to change relative positions of the first measurement end13-1and the base3and of the second measurement end14-1and the first splint4or the second splint5.

As shown inFIGS.8and9, the prediction plane3-1of the base3is connected to a tibia sensor21. Two opposite surfaces of the first splint4and the second splint5are connected to a knee sensor22respectively.

Further, as shown inFIG.2a, the movement assembly02includes:a first guide rail6, where the first guide rail is arranged in a first direction and mounted at a bottom of the fixation seat1, and the first direction is arranged parallel to a bottom surface of the fixation seat1; and the first guide rail6is in a rectangular recess structure, and is formed by a bottom plate and four rectangular side plates that are arranged on the bottom plate and connected in sequence; and the rectangular side plates are perpendicular to the bottom plate;a first slide block7, where the first slide block is movably arranged on the first guide rail6and configured to mount the measurement assembly01; anda first drive member8, where the first drive member is arranged at a side, relatively far away from the fixation seat1, of the first guide rail6; as shown inFIG.10, a drive end18of the first drive member8is provided with a first screw19, the first screw19corresponds to and is arranged parallel to the first guide rail6, and the first slide block7is in threaded connection to the first screw19; and in this case, a type of the first drive member8includes, for example, a drive motor having a model including KY80AS0202-15.

The drive end18of the first drive member8drives the first screw19to rotate. Since the two rectangular side plates of the first guide rail6in a guide direction have a restrictive effect on the first slide block7, the first slide block7can be prevented from rotating around the first screw19and can move along the first screw19, that is, in the first direction, so as to change relative positions in the first direction of the first measurement end13-1and the base3and of the second measurement end14-1and the first splint4or the second splint5.

Further, as shown inFIG.2a, the movement assembly02further includes:a second guide rail9, where the second guide rail is arranged in a second direction and mounted on the first slide block7, and the second direction is perpendicular to the first direction;the first slide block7may drive the second guide rail9to move in the first direction when moving, and the second guide rail9is a rectangular recess structure, and is formed by a bottom plate and four rectangular side plates that are arranged on the bottom plate and connected in sequence; and the rectangular side plates are perpendicular to the bottom plate;a second slide block10, where the second slide block is movably arranged on the second guide rail9and configured to mount the measurement assembly01; anda second drive member11, where the second drive member is arranged at a side, relatively far away from the first slide block7, of the second guide rail9; as shown inFIG.11, a drive end18of the second drive member11is provided with a second screw20, the second screw20corresponds to and is arranged parallel to the second guide rail9, and the second slide block10is in threaded connection to the second screw20; and in this case, a type of the second drive member11includes, for example, a drive motor having a model including KY80AS0202-15.

The drive end18of the second drive member11drives the second screw20to rotate. Since the two rectangular side plates of the second guide rail9in a guide direction have a restrictive effect on the second slide block10, the second slide block10can be prevented from rotating around the second screw20and can move along the second screw20, that is, in the second direction, so as to change relative positions in the second direction of the first measurement end13-1and the base3and of the second measurement end14-1and the first splint4or the second splint5.

Further, as shown inFIGS.6aand6b, the measurement assembly01includes:a mounting shaft12provided with a first end12-1and a second end12-2, where the first end12-1is, for example, a left end of the mounting shaft12, and the second end12-2is, for example, a right end of the mounting shaft12as shown inFIG.6b;a first distance measurement member13and a second distance measurement member14, where the first distance measurement member and the second distance measurement member are arranged at the first end12-1, a measurement end of the first distance measurement member13is the first measurement end13-1, and a measurement end of the second distance measurement member14is the second measurement end14-1; and in this case, a type of the first distance measurement member13and the second distance measurement member14includes, for example, a laser displacement sensor having a model including PANASONIC HG-C1400-P; anda third drive member15, where the third drive member is arranged at a side, close to the fixation seat1, of the second slide block10, and the third drive member15is provided with a drive end18connected to the second end12-2.

As shown inFIG.6a, the third drive member15includes a servo motor mounted on the second slide block10, the servo motor is provided with a drive shaft, and a driving wheel is mounted on the drive shaft; the third drive member15further includes a driven wheel arranged at the second end12-2of the mounting shaft12, and the driving wheel is connected to the driven wheel by a belt; and the drive shaft of the servo motor drives the driving wheel to rotate, and the driven wheel is driven by the belt to rotate, such that the mounting shaft12rotates, and the first distance measurement member13and the second distance measurement member14rotate clockwise by 180°.

In this case, a model of the servo motor includes, for example, 40CB010C-500000.

The third drive member15may drive the mounting shaft12to rotate around its own axis, such that the second measurement end14-1is changed to face the first splint4or the second splint5.

Further, as shown inFIG.7, the tool further includes:a limit recess15-1, where the limit recess is provided on the third drive member15. As shown inFIG.6b, the third drive member15is provided with a housing covering the driven wheel, the housing is connected to the second slide block10, and is provided with the limit recess15-1and an accommodation recess that are in communication with an interior of the housing, and the accommodation recess may allow the belt to pass therethrough and operate normally. The limit recess15-1is arranged far away from the second slide block10relative to the accommodation recess. The mounting shaft12may penetrate the housing to be connected to the driven wheel, and may maintain normal operation. In this case, an angle formed by a connection line that is between two ends of the limit recess15-1and a center point of a cross section of the housing is 180°.

As shown inFIGS.4and6b, a limit protrusion16is arranged in the limit recess15-1, and the limit protrusion16is connected to a side wall of the mounting shaft12and is configured to limit a rotatable angle of the mounting shaft12rotating around its own axis. Specifically, the limit protrusion16may rotate along with the mounting shaft12. When the limit protrusion16touches any end side wall of the limit recess15-1, the mounting shaft12is stopped from continuously rotating. In this case, the second measurement end14-1just rotates by 180°, and may measure a distance between the second measurement end and an adjacent splint.

The present disclosure provides a method for measuring a parallelism and an angle of a shank skeleton of a vehicle crash dummy implemented based on the tool according to Example 1.

Before a parallelism error and an angle error are measured according to the following method, it is necessary to mount a base3of a shank U-shaped member2to be measured on a fixation seat1. In addition, it is set that initial positions of a first measurement end13-1and a second measurement end14-1in a first direction are at a side, relatively close to a drive end18of a movement assembly02, of the base3, and stop positions of the first measurement end13-1and the second measurement end14-1in the first direction are at a side, relatively far away from the drive end18of the movement assembly02, of the base3; and initial positions of the first measurement end13-1and the second measurement end14-1in a second direction are at a side, relatively close to the base3, of a first splint4or a second splint5, and stop positions of the first measurement end13-1and the second measurement end14-1in the second direction are at a side, relatively far away from the base3, of the first splint4or the second splint5.

As shown inFIG.1, the method includes:

S10. The movement assembly02drives a measurement assembly01to move in the first direction and towards a side close to the fixation seat1, the first measurement end13-1measures a real-time distance between the first measurement end and a prediction plane3-1and outputs a first curve, and the second measurement end14-1measures a real-time distance between the second measurement end and the first splint4and outputs a second curve, where the first direction and a bottom surface of the fixation seat1are arranged in parallel.

In this case, the real-time distance, measured by the first measurement end13-1, between the first measurement end and the prediction plane3-1is a distance between the first measurement end13-1and the prediction plane3-1measured by the first measurement end13-1when moving from the initial position to the stop position in the first direction. The real-time distance, measured by the second measurement end14-1, between the second measurement end and the first splint4is a distance between the second measurement end14-1and the first splint4measured by the second measurement end14-1when moving from the initial position to the stop position in the first direction.

The first measurement end13-1measures once the distance between the first measurement end and the prediction plane3-1every set duration, and the set duration is set according to actual demand. In this way, a plurality of discrete distances may be obtained after a period of time, and these discrete distances and corresponding measurement time are input into a controller. The controller outputs a measurement time-distance curve after performing fitting on the distances and corresponding measurement time, and in this case, the first curve is output. A second curve, a third curve, a fourth curve and a fifth curve may also be output according to the above process.

In this case, a type of the controller includes, for example, Programmable Controller MY-26A PLC.

S20. The movement assembly02drives the measurement assembly01to move in the second direction and towards a side far away from the base3, and the second measurement end14-1measures a real-time distance between the second measurement end and the first splint4and outputs the third curve, where the second direction is perpendicular to the first direction. In this case, the real-time distance, measured by the second measurement end14-1, between the second measurement end and the first splint4is a distance between the second measurement end14-1and the first splint4measured by the second measurement end14-1when moving from the initial position to the stop position in the second direction.

S30. The measurement assembly01is caused to rotate clockwise by 180°, the movement assembly02drives the measurement assembly01to move in a second direction and towards a side close to the base3, and the second measurement end14-1measures a real-time distance between the second measurement end and the second splint5and outputs the fourth curve. In this case, the real-time distance, measured by the second measurement end14-1, between the second measurement end and the second splint5is a distance between the second measurement end14-1and the second splint5measured by the second measurement end14-1when moving from the initial position to the stop position in the second direction.

S40. The movement assembly02drives the measurement assembly01to move in the first direction and towards a side far away from the fixation seat1, and the second measurement end14-1measures a real-time distance between the second measurement end and the second splint5and outputs the fifth curve. In this case, the real-time distance, measured by the second measurement end14-1, between the second measurement end and the second splint5is a distance between the second measurement end14-1and the second splint5measured by the second measurement end14-1when moving from the initial position to the stop position in the first direction.

S50. An ideal datum plane is obtained.

As shown inFIG.5, the step that an ideal datum plane is obtained specifically includes:a center of a bottom surface of a magnetic fastener17is taken as an origin. As shown inFIG.5, the origin is point o, an extension line that passes the center of the bottom surface of the magnetic fastener17and is perpendicular to the first direction and the second direction is taken as an X axis, an extension line that passes the center of the bottom surface of the magnetic fastener17and is parallel to the first direction is taken as a Y axis, an extension line that passes a center of the prediction plane3-1and is parallel to the second direction is taken as a Z axis, and a three-dimensional coordinate system is constructed.

In the three-dimensional coordinate system, center coordinate points of four bolt holes on the bottom surface of the magnetic fastener17are obtained. As shown inFIG.5, the center coordinate points of the four bolt holes are w1, w2, w3and w respectively, and the corresponding coordinates are (x1, y1), (x2, y2), (x3, y3) and (x4, y4) in sequence.

Two ideal datum points are computed according to the four center coordinate points, where the ideal datum point is a midpoint coordinate point of a line that is perpendicular to the first direction and the second direction and connects two center coordinate points. As shown inFIG.5, the two ideal datum points are r1and r2respectively, and corresponding coordinates are (0, y5) and (0, y6) in sequence.

According to the two ideal datum points, an ideal straight line is obtained. As shown inFIG.5, the ideal straight line is a line segment formed between r1and r2.

An ideal datum plane is obtained according to the ideal straight line.

Further, the step that an ideal datum plane is obtained according to the ideal straight line specifically includes:a coordinate plane where the ideal straight line is located is obtained from the three-dimensional coordinate system.

The ideal straight line is extended in a coordinate axis direction that does not belong to the coordinate plane, and the ideal datum plane is obtained.

As shown inFIG.5, the coordinate plane where the ideal straight line is located is oXY, and the coordinate axis that does not belong to the coordinate plane is Z axis. Accordingly, a coordinate plane where the ideal datum plane obtained is located is oYZ.

S60. Five parallelism errors are computed according to the first curve, the second curve, the third curve, the fourth curve and the fifth curve by taking the ideal datum plane as a datum.

S70. It is determined that a preset angle β is equal to a standard angle α, and the first splint4and the second splint5are parallel to the ideal datum plane respectively when all parallelism errors fall within a parallelism tolerance interval. That is, the shank U-shaped member2currently tested is qualified.

In this case, the parallelism tolerance interval may be ±0.5 mm.

Further, the step that it is determined that a preset angle β is equal to a standard angle α includes:

The ideal datum plane is taken as a datum, and coordinates of data points of the first curve in the three-dimensional coordinate system are obtained.

A corresponding line segment corresponding to each data point is obtained according to coordinates of the origin and the data points.

An actual included angle corresponding to each data point is computed according to an included angle that is formed between the line segment corresponding to each data point and the X axis.

It is determined that the preset angle β of the base3is equal to the standard angle α when differences between all actual included angles and the standard angle α fall within an angle tolerance interval.

In this case, the angle tolerance interval may be ±20′.

According to the present disclosure, the base3of the shank U-shaped member2is mounted on the magnetic fastener17having the standard angle α, such that the surface, far away from the magnetic fastener17, of the base3mounted forms the prediction plane3-1that may be measured by the first measurement end13-1. Based on the real-time distance, measured by the first measurement end13-1, between the first measurement end and the prediction plane3-1, the first curve is obtained, and the parallelism error is computed according to a relation between the first curve and the ideal datum plane. It is determined that the prediction plane3-1and the ideal datum plane are parallel to each other when the parallelism error falls within the parallelism tolerance interval. In this case, the prediction plane3-1is also parallel to the bottom surface of the magnetic fastener17, that is, the preset angle β of the base3and the standard angle α of the magnetic fastener17are a pair of alternate interior angles, and the preset angle β is equal to the standard angle α. By determining whether the parallelism error of the prediction plane3-1satisfies standards, and then indirectly determining whether the preset angle β of the base3satisfies standards, a process of measuring and determining is more simplified.

Similarly, the real-time distances between the second measurement end and the first splint4and between the second measurement end and the second splint5are measured by the second measurement end14-1, and the second curve, the third curve, the fourth curve and the fifth curve are obtained accordingly. Four parallelism errors are computed according to relations between the curves and the ideal datum plane. When all the four parallelism errors fall within the parallelism tolerance interval, it is determined that the first splint4and the second splint5are parallel to the ideal datum plane, that is, the first splint4and the second splint5are parallel to each other, and the first splint4and the second splint5are also perpendicular to the prediction plane3-1respectively since the prediction plane3-1is also parallel to the bottom surface of the fixation seat1. Compared with a traditional measurement method, the present disclosure is not limited by space, the angle tolerance that is difficult to measure accurately is converted into the parallelism tolerance that is easy to measure, such that whether the angle tolerance satisfies standards is indirectly determined, that is, the angle of the base3and the parallelisms of the two splints can be measured quickly, and the condition that the measurement assembly01directly comes into contact with the shank U-shaped member2, and damages the surface of the shank U-shaped member2is avoided while making an entire measurement process more convenient and rapid.

What is described above is merely explanation of preferred examples of the present disclosure and applied technical principles. It should be understood by those skilled in the art that the scope of invention involved in the present disclosure is not limited to a technical solution formed by a specific combination of the technical features described above, but should further cover other technical solutions formed by any random combination of the technical features described above or their equivalent features without departing from the inventive concepts, for example, a technical solution formed by interchanging the features described above and (non-limitative) technical features having similar functions as disclosed in the present disclosure.