WO2019180487A1

WO2019180487A1 - System and method for measuring surfaces of moving objects

Info

Publication number: WO2019180487A1
Application number: PCT/IB2018/051871
Authority: WO
Inventors: Roy Ellery JAQUE CANDIA; Alfonso Eliot MERINO DIAZ; Luis Antonio HERRERA DEVAUD
Original assignee: Bailac Servicios En Ahorros De Neumaticos Ltda.
Priority date: 2018-03-20
Filing date: 2018-03-20
Publication date: 2019-09-26
Also published as: CL2018002550A1

Abstract

A system and method for measuring surfaces of moving objects, comprising: a light emitting device, which is located above the surface of the moving object and which projects a beam of light in the form of a transverse line over the surface; an image capturing device, located in an inclined position with respect to the beam of light emitted by the light emitting device and which captures images in time of the projected transverse line; means for determining a speed and an acceleration, respectively, of the moving object; and a processing device that allows to identify in the captured images the transverse line projected onto the moving object, determining a height of a plurality of points on said transverse line at a specific time, and using the information of the speed and acceleration to reconstruct in time a three- dimensional profile of the surface of the moving object.

Description

SYSTEM AND METHOD FOR MEASURING SURFACES OF MOVING OBJECTS

The present invention relates to remote monitoring systems and the measurement of wear on moving surfaces, especially for equipment used in large-scale mining. In particular, the present invention consists of a surface measuring system for moving objects, which allows the detection of abnormalities, cuts or foreign elements on the surface of the objects.

BACKGROUND

In order to meet the high demand for mineral resources, large-scale mining must maintain high productivity, which in practice requires the transfer and processing of large quantities of raw materials. In this context, the scheduled maintenance of the different equipment involved in the process is of vital importance, as it helps to ensure greater availability and reliability of the same, avoiding unplanned stops for the repair of equipment, which result in a high opportunity cost because production must be temporarily stopped.

In view of the above, material transfer equipment such as conveyor belts and trucks play a key role in the production of mining operations, and the detention of any of these, either scheduled or unscheduled, translates into high costs. This is the case, for example, of the giant tires for mining trucks ("Off-Road" trucks), which are currently monitored periodically and in-situ by qualified staff, which normally carries out the review of each equipment manually through a "depth meter", with which the remaining rubber is measured at different points on the surface of the tires.

In this way, the measurement of the remaining rubber should be made with field staff in specific locations, forcing the mining team to leave its work cycle and go to the measurement location, where it should be checked each of the tires, stopping their production for a considerable time. Usually, a field monitoring group can complete the review of an entire fleet of equipment in approximately 1 week.

On the other hand, the measurement of rubber remaining is not usually well measured, not only because of the human factor but because the current methodology only allows measurements at specific points of the tire, using the depth meter, and not in all its surface, which limits the efficiency of the process and does not allow a good preventive programming of tire care.

As a result of the above, there is a need to have tire wear measurement equipment that can operate remotely and automatically. A solution to the proposed problem is disclosed in WO 2008/061770 A1 , which describes a system for measuring the tread depth of vehicle tires, which comprises one or more units of measurement located at specific locations on the tire, and where each of them detects a distance between the tire and the unit of measurement at that specific point. Each measuring unit uses a transmitter that emits a signal in the form of electromagnetic radiation at a certain point on the tire, and a receiver that captures the reflection of said signal on that same point in the tire. In this way, each measuring unit determines the distance between it and the surface of the tire at the measured point, and when measuring at different points of the tire you can compare the distances between the measured points to determine the different tire surface heights.

However, although this document shows a system that allows to determine the level of tire wear in an automated way, this system requires that the vehicle is stopped and is not applicable in addition to large mining trucks ("off-road"), since it is specifically designed for small or conventional vehicles. These drawbacks are due to the geometry of the treads of conventional vehicles, which are completely different from those of a giant tire for mining trucks, as can be seen in figure 1 . In conventional vehicles the treads are extended along the entire surface of the tire with a substantially uniform geometry, in a longitudinal direction. Therefore, when the wheel is in motion, the height difference between the surface of the tread and the adjacent recess is kept substantially constant. Due to this principle, the different wear measurement devices of the prior art, being directed to conventional vehicles, are limited to locating sensors at fixed points on the surface of the tire, to make measurements at specific points on said surface, in such a way to calculate the difference in height between the surface of the tread and the adjacent recess.

However, the methodology described in the prior art is not applicable to the giant tires used in mining, since in these the treads do not extend along the surface of the tire with a uniform geometry in the direction of rotation of the wheel, but rather show perforations or recesses with different orientations and angles. Consequently, when the wheel is in motion, the height difference between two adjacent points on the surface does not keep constant. This difference in geometry is basically due to the fact that mining trucks are designed to transport a high tonnage, which causes the tires to overheat during use. To solve this problem and allow better heat resistance, giant tires are designed with different geometries than conventional tires, which allow better ventilation, letting heat escape through large recesses. In view of the inability of prior art systems to perform measurements of wear on large tires, such as those used in mining trucks, there is a need to have a wear measurement system that can be applied independently of the geometry of the tire surface, that can take data efficiently and can operate while the vehicle is in motion.

To correct the aforementioned deficiencies, a system for measuring the surfaces of objects in motion is presented, which allows the detection of abnormalities in the surface, such as wear, cuts or the presence of foreign objects on the surface. The system comprises:

• a light emitting device, which is located on the moving surface and projects a light beam in the form of a transverse line on the surface;

• an image capture device, located in an inclined position with respect to the light beam emitted by the light emitting device and which captures images in time of the projected transverse line;

• means for determining the speed and acceleration of the moving object; and

• a processor that allows to identify in the captured images the transverse line projected onto the moving object, determine a height of a plurality of points on said transverse line, and use the information of the speed and acceleration to reconstruct in time the surface of the object in motion.

The present invention also contemplates the provision of a method of measuring moving surfaces, comprising the steps of:

• projecting a light beam in the form of a transverse line on a moving surface, from a location on the surface of the object;

• capturing images in time of the projected transverse line, through an image capture device that is located in an inclined position with respect to the projection of the light beam;

• determining a speed and an acceleration in a given time of the moving object; and

• identifying in the captured images the transverse line projected on the surface of the object, determining the height of a plurality of points on said transverse line, and use the information of the speed and acceleration to reconstruct in time a three-dimensional profile of the surface of the moving object. Additionally, the invention includes a remote communication and monitoring system for monitoring the surfaces of one or more moving equipment, which comprises:

• one or more measuring systems of moving surfaces, each located in a field equipment, where the system identifies captured images of a light beam in the form of a transverse line projected on the surface of the equipment, determining a height of a plurality of points on said line, and reconstructing a three-dimensional profile of the surface of the moving object; y

• one or more servers that communicate with the measurement systems, which store the monitoring information obtained by each system, and which allow to display said information in a user interface; wherein through the user interface it is possible to selectively activate each measurement system remotely and receive in real time information related the three-dimensional profile of the surface of each equipment in the field by means of each measurement system.

In this way, through the systems and the method described in the present invention it is possible to carry out a measurement of the state of the equipment in an automated and remote way, with which it is possible to maintain a monitoring of multiple equipment in one central location and distance, while the equipment(s) is in full operation and automatically.

Based on the foregoing, various operational advantages arise from the configurations of the present invention, of which, for example, the following may be mentioned:

1 .- The times associated to the measurement of the equipment are reduced: as previously mentioned, at present the measurement of the rubber remaining in large tires is carried out with staff in the field, causing the equipment to stop and exit of its work cycle, the rules of procedure of the tasks are met and manual check of different points on the surface of the tire is carried out. This means stopping the production of the equipment mining for a considerable time, which results into an important cost for any mining site.

2.- Advance planning of equipment attention: the system of the present invention allows to monitor in real time the state of the equipment, detecting early possible anomalies in the surface thereof, such as a decrease in the remaining rubber, microcracks on the surface, incrustation of strange objects such as stones or others, or even chains in bad condition in the case of mining tires. Through an appropriate analysis of this information it is possible to carry out an advance planning for each team, in order to optimize the future operation of the same.

3.- Increase the safety of workers in the field: The danger of workers in the field is reduced due to the system of the present invention since the measurement procedures in the field are avoided or diminished considerably, because many of the tasks required they can be carried out remotely and automated. In large mining, due to the large size of the equipment that must be monitored, accidents are usually fatal, for example, a blowout of a mining tire can throw pieces of it up to 300 meters away, which is not the case with a rubber tire of conventional vehicles.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a diagram of a front view of a measurement system for conventional vehicle tires, according to prior art configurations.

Figure 2 shows a diagram of the different elements of a configuration of the present invention.

Figure 3 shows a diagram of an example of an image captured by the image capturing device at a specific time, wherein it is possible to see the line of the light beam projected on a tire for mining trucks.

Figure 4 shows an example of the information obtained through the processor of the present invention, once the line of the light beam projecting on the object of Figure 3 has been processed.

Figure 5a shows an example of an application of the invention in a tire, which is used to measure its surface by the present invention.

Figure 5b shows an example of a three-dimensional profile of the tire of Figure 5a, obtained by the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In a reference to the figures, and as can be seen particularly in FIG. 2, the present invention consists of a system for measuring surfaces of objects in motion, which allows the detection of surface abnormalities, such as wear, cuts or the presence of foreign elements on the surface. The system comprises: • a light emitting device (1), which is located on the surface of the moving object (3) and projects a light beam (4) in the form of a transverse line on the surface;

• an image capturing device (2), located in an inclined position with respect to the light beam emitted by the light emitting device (1 ) and which captures images in time of the projected transverse line;

• means for determining the speed and acceleration of the moving object; and

• a processor that allows to identify in the captured images the transverse line projected on the moving object (3), determining a height of a plurality of points on said transverse line, and using the information of speed and acceleration to reconstruct in time a three-dimensional profile of the surface of the moving object.

In this way, according to the system described above, the light emitting device projects the light beam on the surface to be scanned and the capture device captures images at time intervals, or preferably captures images in the form of a video, previous calibration of a respective lens and the type of light used. With this information a triangulation is applied on each point of the projected line and the surface of the object that is being slid is reconstructed by means of the processor, frame by frame. In a preferred case, said surface corresponds to the tread of a tire for mining trucks, which could even have chains installed during the operation.

As seen in Figure 2, due to the arrangement of the devices of the system, wherein the image capturing device (2) is arranged at a distance "d" from the light emitting device (1 ) and with an angle "a" with respect to the projection of the ray of light, it is possible to determine by a trigonometric calculation the height "h", which is defined as the distance between the device of emission of light and the surface in motion at a given time.

Due to the location of the image capturing device (2), it captures an image as shown in figure 3, wherein the transverse line projected on the surface is adapted to the form of the surface of the moving object, at a given moment. In this way, by means of the interaction of the devices of the measurement system it is possible to establish the height of each point illuminated by the line projected from a self -defined coordinate axis.

For its part, the processor is able to identify the line illuminated on the surface of the object, as shown in Figure 4, differentiating the heights of the points at a particular time and, by using the speed and acceleration, it is possible to assign the information of each point in a given time with a longitudinal location on the surface of the moving object. In this way, it is possible reconstruct a three-dimensional profile of the moving object, as shown in Figures 5a and 5b.

Figures 5a and 5b show an example of a three-dimensional profile of a tire for mining trucks, where the level of detail that can be obtained by the present invention for a moving object can be appreciated, being able to clearly identify the treads, or other objects such as chains or strange elements.

From the three-dimensional profile obtained from the moving object, and considering previous information about the initial characteristics of the object, it is possible to obtain a measurement of the wear of the surface of the tire. For example, calculate the remaining rubber of a tire for mining trucks, in the different positions of the band of rolling, allowing to take a detailed control of the form of the wear.

Additionally, the system is able to identify strange elements such as rocks embedded in the tires, or determine the condition of the chains when they are used in the operation of the mining truck. The monitoring of chains can be carried out in order to optimize the maintenance of the mines, evaluating the level of wear or identifying in advance possible failures.

In this way, considering the application of the present invention in mining truck tires, it is possible to detect, for example: a) Gas bubbles inside the tire that occur due to temperature increases, where the rubber generates gases that accumulate in bubbles between the layers of rubber. In this case, by identifying the location of malformations it is possible to detect these accumulations of gas and take corrective actions in time. b) Foreign elements on the surface of the tire. The great weight of the tire causes rocks to be embedded, as time goes by are pushed by other embedded rocks, advancing more and more towards the interior of the tire, generating the risk of a blowout. These rocks are large and protrude from the surface of the tire, so they are easily detected by the system. c) Cuts on the surface of the tire that are generated due to the torque in the rubber when in contact with the floor and the rocks, which produces cracks that are advancing towards the interior of the tire. These cuts generate friction, which increases the temperature and makes them visible through a thermal camera, allowing corrective actions to be taken in time to repair. In a preferred embodiment of the invention, the type of light used in the light emitting device is a laser. However, other options are equally possible as long as they allow information to be obtained in an adequate manner with respect to the surface of the moving object.

Similarly, the image capturing device may preferably be a CMOS photosensitive sensor encapsulated in a pinhole camera with a lens. Alternatively, an infrared sensor could be used in order to identify temperature profiles on the moving surface.

The system of the present invention can additionally comprising a TAG reader that allows reading all the components installed in the moving object, in order to associate the object with its status and work statistics. This TAG reader is used for the identification of components of the object, and is applicable to certain types of applications, such as tire use. Its function is to identify each tire installed in each position of the equipment and to keep a history of time of use with its eventualities, in order not to run the risk of failures due to exceeding its time of use or due to possible failures detected.

One of the usual problems in the use of the invention, such as during the operation of tires or conveyor belts, is the presence of mud in the surface of the moving object, which can jump from the moving surface to any of the devices of the system, affecting the quality and reliability of the captured images. In order to overcome this issue, in an alternative embodiment of the invention the system can comprise a protective casing that permanently protects its constituent elements against the mud. This casing comprises a movable cover that is driven by one or more motors to selectively move the cover from a closed position to an open position, allowing the image capturing device to carry out the capture of images for a short period of time when the cover is in an open position, and protecting the device and the other elements when the cover is in a closed position.

On the other hand, and as previously described, the present invention also contemplates the provision of a method for measuring surfaces in motion, comprising the steps of:

• projecting a light beam in the form of a transverse line over a moving surface, from a location above the surface;

• capture images in time of the projected transverse line, from an image capturing device that is in an inclined position with respect of the projection of the bean of light.

• determining a speed and an acceleration in time of the moving object; and • identifying in the captured images the transverse line projected on the surface of the object, determining a height of a plurality of points on the transverse line, and using the speed and acceleration information of the object to reconstruct in an three-dimensional profile of the surface of the moving object. Preferably, the step of identifying the transverse line projected on the surface of the object comprising digitizing the image captured by the image capture device to define each point of the projected line and reconstructing the surface of the object that is being slid by frame.

Additionally, the step of using the speed and acceleration information to reconstruct a three- dimensional profile over time comprising assigning the obtained information, in order to assign to each point of the line in the digitized image a specific time, associated with a longitudinal location on the surface of the object in motion.

For its part, the invention also contemplates a remote communication and monitoring system for the supervision of the surface of moving equipment, comprising:

• one or more systems for measuring moving surfaces, each located in an equipment in the field, wherein the system identifies captured images of a light beam in the form of a transverse line projected on the surface of the equipment, determining a height of a plurality of points on said line, and reconstructing in time a three-dimensional profile of the surface of the moving object; and

• one or more servers that communicate with the measurement systems, which store the monitoring information obtained by each system, and which allow to display said information in a user interface;

Where in the user interface it is possible to selectively activate each measurement system remotely and receiving in real time information related to the three-dimensional profile of the surface of each equipment in the field by means of each measurement system. Preferably, the remote communication and monitoring system can be configured to carry out a periodic analysis automatically, or it can be activated through a user's request through the user interface.

Finally, it should be mentioned that the invention has been described mainly with reference to some preferred embodiments, as shown in the figures. However, a person skilled in the art will be able to clearly recognize that other embodiments or modifications are equally possible within the spirit of the invention. For example, the arrangement of the elements or the types of light capture and emission devices used may vary according to the specific requirements of each implementation. Accordingly, the description detailed above is to be understood broadly, the spirit and scope of the invention being limited only by the appended claims.

Claims

1 . A system for measuring surfaces of moving objects, comprising:

a light emitting device, which is located above the surface of the moving object and which projects a beam of light in the form of a transverse line over the surface;

an image capturing device, located in an inclined position with respect to the beam of light emitted by the light emitting device and which captures images in time of the projected transverse line;

means for determining a speed and an acceleration, respectively, of the moving object; and

a processing device that allows to identify in the captured images the transverse line projected onto the moving object, determining a height of a plurality of points on said transverse line at a specific time, and using the information of the speed and acceleration to reconstruct in time a three-dimensional profile of the surface of the moving object.

2. A system for measuring surfaces according to claim 1 , wherein the image capturing device is arranged at a distance from the light emitting device and angled with respect to the projection of the beam of light, whereby a distance between the light emitting device and the moving surface is determined at a given time.

3. A system for measuring surfaces according to any of the preceding claims, wherein the type of light used in the light emitting device is a laser.

4. A system for measuring surfaces according to any of the preceding claims, wherein the image capturing device corresponds to a photosensitive sensor encapsulated in a pinhole camera with a lens.

5. A system for measuring surfaces according to any of the preceding claims, further comprising an infrared sensor that allows to identify temperature profiles on the moving surface.

6. A system for measuring surfaces according to any of the preceding claims, wherein the surface corresponds to the tire tread of a mining truck tire.

7. A system for measuring surfaces according to claim 6, wherein the system allows to identify the wear of the surface of the tire, the presence of foreign objects in the surface or the condition of chains installed for the operation of the tire.

8. A system for measuring surfaces according to claim 6, further comprising a TAG reader that allows the tire to be associated with a status, operation statistics and a usage time history.

9. A system for measuring surfaces according to any of the preceding claims, further comprising a protective casing that permanently protects the elements of the system against the mud, the casing comprising a movable cover that is driven by one or more motors to selectively move the cover from a closed position to an open position, allowing the image capturing device to carry out the capture of images for a short period of time when the cover is in an open position, and protecting the device and the other elements when the cover is in a closed position.

10. A method for measuring surfaces of moving objects, comprising the steps of:

projecting a beam of light in the form of a transverse line over a moving surface, from a location above the surface;

capturing images in time of the projected transverse line, from an image capturing device that is located in an inclined position with respect to the projection of the beam of light;

determining a speed and an acceleration in time of the moving object; and

identifying in the captured images the transverse line projected on the surface of the object, determining a height of a plurality of points on the transverse line identified in time, and using the velocity and acceleration information of the object to reconstruct a three- dimensional profile of the surface of the moving object.

1 1. A method for measuring surfaces according to claim 10, wherein the step of determining the height of the plurality of points on the transverse line comprises identifying a distance between the light emitting device and the moving surface at a given instant by means of the inclined position of the image capturing device with respect to the projection of the beam of light.

12. A method for measuring surfaces according to claim 10, wherein the step of identifying the transverse line projected onto the surface of the object comprises digitizing the image captured by the image capturing device to define each point of the projected line and reconstructing frame by frame the surface of the moving object.

13. A method for measuring surfaces according to claim 10, wherein the step of using the velocity and acceleration information to reconstruct in time a three-dimensional profile comprises assigning the speed and acceleration information to each point of the line in the digitized image at a certain time, so as to relate each point with a longitudinal location on the surface of the moving object.

14. A remote communication and monitoring system for the supervision of surfaces of moving equipment, comprising:

one or more systems for measuring moving surfaces, each located in an equipment in the field, wherein the system identifies captured images of a beam of light in the form of a transverse line projected on the surface of the equipment, determining a height of a plurality of points on said line, and reconstructing in time a three-dimensional profile of the surface of the moving object; and

one or more servers that communicate with the measurement systems, which store the monitoring information obtained by each system, and which allow to display said information in a user interface;

wherein in the user interface it is possible to selectively activate each measurement system remotely, and receiving in real time information related to the three-dimensional profile of the surface of each equipment in the field by means of each measurement system.

15. A remote communication and monitoring system according to claim 14, wherein the remote communication and monitoring system may be configured to automatically perform a periodic analysis, or it may be activated by a request of a user through the user interface.