This application claims benefit of priority to prior-filed Peru Application 001494-2021/DIN filed Sep. 10, 2021 of which the entire contents thereof are hereby incorporated by reference into the present disclosure.
The invention mainly relates to systems and methods for monitoring mineral loading in mining excavation equipment.
Heavy equipment, such as excavators, are routinely employed in mineral and earth mining. Such machines are equipped with a shovel or bucket and quickly move loose ore into waiting vehicles for downstream processing. The operating implement that engages the loose rock are equipped with one or more ground engaging tools (GET) that is designed to be sacrificed at certain stages of wear. Because these parts have high hardness, loss of the part may damage downstream equipment such as crushers and conveyor belts. Such events, while rare, can result in significant downtime and safety hazards. It is therefore important for mining operations to detect the loss of a wear part as close to the loss event as possible.
Various techniques to detect GET loss events have been contemplated in the prior art. For example, techniques such as capturing successive images of the operating implement and measuring the intensity value of the pixels to determine whether a subset of pixels correspond to the wear part. Other techniques embed RFID modules within the GET to establish its position.
However, since actual GET loss events only happen on average once per excavator per year, many of these systems suffer from an unacceptable level of false alerts, resulting in unnecessary work stoppage or operator fatigue and disregard of alarms (the “cry-wolf syndrome”), or require specialized GETs (such as in RFID implementations) that are very expensive.
It is also impractical to employ humans for frequent inspections because the size of the excavators are massive and present a danger to personnel nearby. They must also work day or night, in very hot or very cold conditions, or in inclement weather.
The present invention, named the “GET smart” system, uses AI modeling and neural network technology to efficiently identify wear part loss events and provide other useful metrics during excavator operation to improve efficiency and reduce downtime.
In one embodiment, the invention monitors the integrity of ground engaging tools (GETs), which have the potential to cause catastrophic damage within the mining operations downstream from earth moving steps.
The invention uses a variety of multidimensional sensors to gather information pertaining to the excavator, its components, and its surroundings. All information is then structured into a unique data structure called the enriched tensor and processed in real-time using an embedded system comprising CPUs and tensor processing units (TPUs). The data is processed via statistical and artificial intelligence (AI) techniques, involving neural networks and visual transformers.
The invention uses several parallel and independent processing techniques to produce discrete results, which are evaluated individually by a custom algorithm to accurately detect missing GETs within acceptable false positive rates. Upon identification of a “true positive” event, the invention notifies the operator via an in-cab monitor, and also to remote users via cloud and mobile applications.
Other metrics relevant to the earth-moving process are computed by the invention. These include detecting the wear level of a GET, the volume of minerals per shovel bucket, and the average particle size.
Table 1 is a summary chart of a training dataset.
Processing enclosure 103 comprises essentially a computer to which the software portion of the invention is run, and a power management unit.
The tower assembly 100 may be located on an excavator, as shown in
The environmental sensor, which provides at least inertial data to track movement of the excavator, contains an accelerometer, gyroscope, and magnetometer. It is additionally capable of collecting temperature, atmospheric pressure, humidity, noise, and luminescence data. In an exemplary embodiment, this sensor may be the Bosch XDK. The sensor is installed in the tower assembly.
The sensor enclosure is protected by airblade system 140 which provides conditioned airflow to keep the data collection unit in good working order. The system works by channeling airflow through the top of the enclosure so that it travels past the camera window in a downward direction. This keeps the window clear of dust and moisture buildup and deflects flying debris which may damage the window or the sensors. The conditioned air can also keep the sensors at an optimal operating temperature. This system reduces maintenance requirements and the frequency to which a human is needed to access the physical components.
Central to the GET smart system is a data structure known as the enriched tensor, which stores relevant portions of the sensor data captured by the data collection unit; and the software algorithms that manipulate the enriched tensor known as the AI module.
As shown in
After capturing the raw data, a region of interest (ROI) is calculated by the tensor module 212. This calculation allows the system to efficiently identify the most relevant data for inclusion into the enriched tensor. The ROI is a minimum subset of the data which most likely includes information related to an object of interest.
An ROI may be determined via presets, or even as simply as via IMU data alone. Inertial data collected by the sensor can accurately determine the state of the excavator, whether the shovel is digging or transporting earth, such that the state where the shovel faces up (and the GETs are the most visible) can be optimally determined. The ROI may thus also be time-based, where the system simply ignores the data collected when it knows the shovel faces down and no GETs are visible. By limiting the data, it reduces the likelihood of generating false positives.
In other embodiments, the horizontal lines defining the ROI may be dynamic and generated by taking a center point of detected GETs and applying a minimum and maximum distance to the center point, which is then used as an axis to determine the region where GETs are likely to be found. This technique may prevent occasional edge cases where a GET drifts slightly out of preset areas and results in an incorrect detection. The boundaries of the ROI are different for each implementation and are customizable based on parameters such as the size of the excavator shovel and position of the sensors. The ROI also may not necessarily be a geometric portion of the entire visible screen; it may be limited to the rectangle or cuboid surrounding an object of interest, such as a GET or the “raw” attachment point after a GET detaches.
Returning to
The region of interest is represented by cuboid 230, which is also the entire volume of the point cloud, because only the portion of the point cloud within the cuboid is present within the enriched tensor. Portions outside are mostly irrelevant and remain unprocessed.
The AI module comprises a 2-dimensional convolutional neural network (2D-CNN) configured to process the 2-D image portion of the enriched tensor. The output is fed to a classification model, which makes a refined prediction. Both of these outputs are retained for later use. A weighting process gives a higher score when the outputs agree and a lower score when the outputs do not agree. In a preferred embodiment, the 2D-CNN may be a single shot detector (SSD) with a ResNet-18 neural network as backbone. The classification model may be a dense neural network (DNN), which is a CNN that is 18 to 100 layers deep.
The AI module additionally comprises a 3-dimensional convolutional neural network (3D-CNN) configured to process the point cloud portion of the enriched tensor. This NN is similar to the 2D-CNN except it is trained to process 3-D data. In an exemplary embodiment, this component may be PointPillars.
The AI module further comprises additional calculations used to process depth data to obtain distance to an object of interest, and a recurrent neural network (RNN) to process IMU (inertial) data. An RNN is the preferred embodiment because it is adept at processing time series data, which is what inertial data is structured as. Specifically, a long short-term memory (LSTM) neural network is preferable because it is better at processing long-term dependencies than a regular RNN, and it does not “forget” excavator states that occur only intermittently. Each generates its own outputs.
Finally, the AI module comprises a foundational model, which processes the entire enriched tensor without regard to individual data streams. In a preferred embodiment, the foundational model is not a neural network, but a vision transformer (ViT). A transformer in machine learning is comprised of multiple self-attention layers which are adept at generic learning methods that can be applied to a variety of data modalities. In the GET smart system, it is used to process the entire enriched tensor holistically, and similarly outputs prediction data.
A neural network or deep learning model requires training before they can be used in an application environment. The purpose of model training is to build the best mathematical representation of the relationship between detected data features and a label and inure the relationship to the NN. In the GET smart system, training generally involves providing a dataset comprising information regarding the object of interest that is pre-labeled. The training set can be thought of as a set of “right answers” to which the NN must be accustomed to.
A training dataset is divided into at least three subsets: a training subset is used to improve the performance of NNs through supervised learning; a validation subset is used as a quiz to demonstrate proficiency at a task; and a test subset used to obtain a set of proficiency metrics for the NNs.
Table 1 is a quantitative summary chart of relevant features of a training dataset. In one embodiment, the dataset used comprises 37,104 training images and 4,106 test images. The relevant features (the presence or absence of wear parts) are labeled such that the NN can recognize the features. For example, within a dataset, a tooth object is labeled 92,430 times. An object labeled “raw” is an image of a damaged GET or the raw attachment point 112 (see
The number of features and images in the table are an exemplary embodiment to sufficiently train a 2D-CNN neural network. Each type of model requires its own training dataset. However, it is estimated that at least 10,000 images are required if the dataset were ideal and as diverse as possible; with a less ideal dataset, more than 40,000 images can be needed. For the 3D-CNN that processes point clouds, at least 10,000 point clouds are required.
To reach desired accuracy, 80 to 120 epochs are used per training and between 10 to 20 trainings are performed. The process can take hours or even days. In a preferred embodiment, the training process is implemented on the NVIDIA TAO framework. The training is automated via a pipeline, which runs on dedicated hardware (for training use only) and implemented in Python3.
The procedure for training 3D-CNN is identical to the 2D-CNN in all respects except the intersection of test image labels and predicted labels is three-dimensional. Each model is trained in their own context; for example, only inertial data is used in training the RNN as it will only ever process data obtained from the IMU.
The training dataset is built from a combination of all inputs and sensors collected from similar equipment and environments. Raw data is collected from visual cameras, LIDAR, environmental sensors, IMU, and radar just as in actual operation. However, the GET smart system generates extra training data by manipulating and transforming the initial data set through a process called data augmentation.
The goal of data augmentation is to generate sufficiently diverse training data so the trained AI models are more robust than what is normally achievable through experimentation or simulation. Because actual GET loss events are rare, not all of the dataset needed can be collected in a production environment. Neither are GET loss events captured in sufficiently variable conditions to allow for the training diversity desired.
Some techniques explicitly contemplated are performing mathematical operations to the image, such as presenting a mirror image, tilting the image up to 15 degrees in either direction, zooming in or out, or adjusting the contrast so that the image is brighter or darker.
Other techniques involve applying the operations above to the three-dimensional point cloud. In a preferred embodiment, the point cloud for a particular object of interest is manipulated such that all data points are moved slightly further or closer to a computed point representing the center of the object, generating point clouds of the object that is slightly larger or smaller than the actual object.
In another embodiment, a digital representation of the excavator and the shovel may be generated, comprising synthetic data, in a process known as a digital twin.
One of the primary tasks of the GET smart system is to detect a GET loss event at the moment of occurrence or as close to the event as possible so that the wear part could be located and removed. This should be accomplished with a frequency of false alerts at or below a tolerable level for the operator so that mining operations are not unduly interrupted.
Another task of the system is to detect the wear level of any particular GET. As these parts are sacrificial, wearing is an integral part of their lifecycle. Accurate prediction of a GET nearing the end of its service span can signal a need for preventative maintenance and avoid a GET loss event altogether.
Data selected for processing is queued in the AI module queue and enters the AI module 250, which produces discrete outputs from every model, as explicated supra. These outputs comprise at least a predicted label and an associated confidence level for each label. The outputs comprise at least 3D-FM (3-dimensional foundational model); 3D-CNN; 2D-FM (2-dimensional foundational model); 2D-CNN; 2D classifier; depth; and RNN (inertial) output.
In the figure, the GET within bounding box 413 is lost or damaged. The AI module determines this and assigns it a “raw” label and a confidence level, which is further processed downstream.
To facilitate readability, not all of the bounding boxes or labels are illustrated herein. Note that while the figure is two-dimensional, a three-dimensional result with bounding boxes being cuboids is generated and manipulated mathematically.
In one embodiment, the manager evaluates the output from the 2D classifier and generates a set of labels and confidence levels for each element detected within a preset bounding box. Output from the 3D-CNN is similarly evaluated except only those objects that overlap the 2D bounding boxes are evaluated. If the models further agree on the labels, the object is considered valid.
More holistically, if multiple models report a missing GET with high confidence but the RNN reports that the shovel is in a position where the GET should not be visible, then it is likely a false detection of an errant particle that resembles a missing GET, and an alert is not sounded. If multiple models report a missing GET in a region that is too close or too far away from the region of interest based on depth data, the manager may determine that the detection is not valid.
In this representation of a depth map, at least some of the GETs are shown selected in their ROIs. For each object recognized, a center of mass is calculated and mapped to a corresponding location on the depth map. Only those that are located within the correct distance (an exemplary distance may be between 7-8 meters) are selected for further processing.
The system also determines GET point cloud 424 from LIDAR data delineating the contours of the GET and subsequently a polygon approximation 425 is calculated.
This information is then computed to determine the physical parameters, such as area, mass, measurements, and volume of a GET. Since these parameters are known for a new GET, a level of wear for each individual GET can be computed.
The GET smart system can leverage its AI models to automate certain other tasks without having to physically manipulate or examine the minerals collected. The system performs volumetric analysis of a given shovel load to determine volume and weight of the material scooped up. The system can also provide an estimate of the particle size of the material. As is apparent in the drawings, it is possible to accomplish many different tasks with just one set of sensor data inputs.
Referencing
These metrics are available through the user interface to allow, for instance, the operator to quantify the loads placed on a dump truck so that it is properly and efficiently loaded. Underloading a dump truck causes costly inefficiencies during the earth moving process and overloading a dump truck can cause damage to the truck.
Regarding the particle size app, the typical environment in which the excavators operate is to scoop up material after the mine had already been blasted with explosives. The measure of particle size or granulometry is important to adjust and optimize both the blasting process and downstream processing.
Referencing
This information is then computed to determine the physical parameters such as area and volume per particle. These samples at the surface are representative of the entire contents of the shovel because they are scooped up at random, and thus there is no need to analyze sub-surface components.
The size measurement is then converted to useful metrics which inform the mine blasting process and the processing plant. These metrics are reported to the mine blasting operator through the cloud to allow the mine and plant operators to set mineral processing parameters and provide feedback to blasting operations to detect under or over blasting.
The advantages of these applications in the GET smart system are less physical contact and downtime required to examine or measure the material being extracted and thus increasing efficiency and safety.
All publications and patent applications cited in this specification are herein incorporated by reference as if each individual publication or patent application were specifically, and individually, indicated to be incorporated by reference.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
Number | Date | Country | Kind |
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PE001494-2021/DIN | Sep 2021 | PE | national |
PCT/IB2022/058595 | Sep 2022 | WO | international |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2022/058595 | 9/12/2022 | WO |