ORIGINAL RESEARCH article

Front. Mech. Eng., 19 May 2026

Sec. Digital Manufacturing

Volume 12 - 2026 | https://doi.org/10.3389/fmech.2026.1806266

Automated control of robots in the work zone: a YOLO-Based approach for optimized maintenance

  • 1. Laboratory of Modeling and Simulation of Intelligent Systems, ENSET of Mohammedia, Hassan II University of Casablanca, Casablanca, Morocco

  • 2. Modeling, Information Processing and Control Systems, ENSAM, Moulay Ismail University, Meknes, Morocco

Abstract

Ensuring the safe and reliable operation of industrial robots requires effective monitoring systems capable of detecting abnormal situations within robotic workspaces. In the context of industry 4.0, computer vision techniques offer promising solutions for real-time supervision of industrial environments. This study proposes a vision-based monitoring framework designed to detect the position of an industrial robot relative to predefined operating and restricted zones. A custom dataset was created from a camera installed above the robot workspace, including images captured under different operational conditions. The models were trained to classify robot positions and detect their status in order to alert maintenance personnel when robots leave predefined zones and optimize interventions. The proposed system relies on deep learning object detection and instance segmentation models based on recent YOLO architectures. A comparative evaluation between YOLOv8 and YOLOv11 was first conducted to identify the most suitable architecture for the considered monitoring task. Experimental results show that both models achieve high detection accuracy, with mAP50 values exceeding 98%; while YOLOv8 demonstrates slightly better localization performance and training stability. Consequently, YOLOv8 was selected for further experiments. To evaluate the robustness and generalization capability of the proposed system, a cross-validation protocol was designed using multiple camera viewpoints and varying illumination conditions. The results indicate that multi-view training significantly improves detection robustness, while strict cross view experiments reveal the strong influence of viewpoint variation on model performance. In contrast, illumination changes have a comparatively smaller impact detection accuracy. Overall, the proposed monitoring framework highlights the potential of the models to significantly reduce unplanned downtime and boost the vigilance of maintenance operators, demonstrating their relevance in the context of Industry 4.0.

1 Introduction

Preventive maintenance remains an essential means of preventing costly breakdowns and unplanned stoppages. The integration of artificial intelligence (AI) into industry has revolutionized maintenance strategies, bringing a new dimension to them. In modern industrial environments, AI techniques are widely deployed for process optimization, predictive maintenance, quality improvement, anomaly detection and equipment monitoring (; ). By leveraging machine learning, deep learning, and data analytics, AI based maintenance can extract actionable insights from heterogeneous data source, thereby improving decision making, operational reliability and overall production efficiency (; ).

In this context, the monitoring of industrial equipment, particularly robots and automated systems, is becoming increasingly accessible and effective, in order to prevent collisions and unforeseen malfunctions in defined areas. Computer vision approaches thus represent a major technological advance, guaranteeing safe, supervised operation in real time (). Computer vision-based approaches have therefore emerged as a key technological enabler for intelligent monitoring, offering non-intrusive flexible and real-time supervision of complex industrial workspaces.

Industrial robots are in complex and dynamic environments and are exposed to various types of failures, including mechanical, electrical and software related faults. Maintenance strategies increasingly rely on failure prediction and early anomaly detection to anticipate malfunction and enable proactive interventions (; ; ). The integration of computer vision techniques offers a promising opportunity to strengthen early detection capabilities and improve the responsiveness of maintenance team.

Among deep learning approaches for visual monitoring, object detection models have become particularly effective for identifying and tracking objects within complex scenes. Convolutional Neural Networks (CNNs) have demonstrated remarkable performance in visual recognition tasks and have become the foundation of modern computer vision systems (). A lot of recent real time object detection frameworks such as You Only Look Once (YOLO) family of models have gained significant attention due to their ability to simultaneously perform object localization and classification within a single Neural Network architecture (). The high detection speed and accuracy of YOLO architectures make them particularly suitable for industrial monitoring applications where real time decision making is required.

In industrial robotics, monitoring whether a robot remains within its designated operational workspace is a critical safety requirement. Deviations from predefined work zones may indicate abnormal robot behavior or potential safety risks that require immediate interventions. Vision based monitoring can provide an efficient and flexible solution for detecting such anomalies by analyzing continuously the spatial position of the robot relative to its operation zone.

Our study is part of a maintenance approach aimed at reinforcing the vigilance of teams in charge of interventions and robot parameters setting. The detection of zone exits is a critical anomaly that can generate unexpected risks. In addition, AI-based solutions offer a flexible and cost-effective alternative for monitoring these anomalies. This article adapts YOLO models to robot monitoring in industrial environments, enabling real-time anomaly detection and prevention. The proposed approach is primarily a vision-based monitoring system rather than a full predictive maintenance framework. The contribution of our work lies in the real -time detection of spatial anomalies; such as robot deviations from predefined work zones which can serve as early indicators of abnormal behavior.

From maintenance perspective this monitoring capability supports preventive maintenance strategies by enabling early detection of unsafe zone or non-compliant robot states. Therefore, the proposed system should be considered as a decision support tool that enhances maintenance operations rather than directly performing failure prediction.

2 Related works

Among computer vision approaches, the “You Only Look Once” (YOLO) algorithm, introduced by Redmon in 2016 (). Which has revolutionized real-time object detection thanks to its unified architecture, combining bounding boxes and classification in a single pass (). Unlike traditional two stage detection framework, YOLO formulates object detection as a regression problem, enabling fast inference and making it particularly suitable for real time industrial monitoring applications.

Initially designed for generic tasks (YOLOv1), this algorithm has evolved to meet increased requirements in terms of accuracy and speed. Successive versions (from YOLOv2 to YOLOv11) have incorporated various improvements, including dimensional anchors (YOLOv2), finer spatial segmentations (YOLOv3), and optimization techniques such as the “Bag of Freebies” (YOLOv4) (). Recent versions including YOLOv5, YOLOv8 and YOLOv11 further enhance the architecture by introducing modular designs, improved feature fusion mechanisms and more efficient backbone networks, allowing these models to achieve high detection accuracy while maintaining real-time inference capability.

Due to these advantages, YOLO based approaches have been widely applied in various industrial monitoring and inspection tasks. In the field of infrastructure inspection, YOLO models have been successfully used for road maintenance application, enabling accurate mapping of internal road defects () and YOLO has also optimized the detection of potholes using drones equipped with YOLOv7 (). In industrial maintenance, a variant of YOLO, YOLODFT (), has been used for monitoring electrical equipment. While () has developed an optimized YOLOv8n framework that improves the detection of surface defects on wind turbines by 2.3% compared to reference models.

Recent studies have further demonstrated the effectiveness of yolo architecture for intelligent industrial monitoring and proactive maintenance. For example, () proposed an improved YOLOv8 architecture for industrial surface defect detection, achieving significant improvements in inspection accuracy in manufacturing environments (). Investigated deep learning–based visual inspection systems for Industry 4.0 manufacturing, highlighting the role of computer vision models in automated quality control. In addition (), emphasize that real-time object detection has become an important research area in computer vision.

More recent works have also explored improvement in YOLO architecture for defect detection and safety monitoring (), has demonstrated that the improved YOLOv11 architecture, which incorporates components such as the C3k2 block, improves the efficiency and accuracy of defect detection compared to previous models. In terms of fire safety, YOLO helps improve anomaly detection and maintenance of firefighting equipment in Saudi Arabia (). In the same context (), used YOLO for autonomous vehicle security by combining the strengths of YOLO architectures to ensure better detection of road signs and increased reliability. In the agricultural sector, it is a valuable tool that enables farmers to detect plant diseases early and take preventive action (). Also (), presents the RDW-YOLO algorithm based on YOLOv11, which improves methods for detecting pests in agriculture RDW-YOLO. Finally, in environmental protection, YOLOv6 and YOLOv7 are being used in Indonesia to detect and eliminate plastic waste, particularly bottles floating on the surface of the water ().

Overall, these studies highlight the versatility and robustness of YOLO architectures in real time monitoring and maintenance related tasks, motivation this adaption to industrial robot monitoring and anomaly detection in complex environments.

3 Research methodology

Our study aims to exploit YOLO techniques to facilitate robot preventive maintenance in a collaborative environment, where robots perform automated tasks. To achieve this goal, our approach is based on five main steps as shown in Figure 1: hardware definition, dataset construction, model training and solution installation. Our study also compares the performance of the YOLOv8 and YOLOv11 models.

FIGURE 1

3.1 Dataset creation pipeline

3.1.1 Experimental context

To evaluate a visual monitoring system capable of verifying whether an industrial robot is operating within its authorized work area, an experimental setup was established around an ABB IRB 1100 robotic manipulator installed in the M2S2I laboratory at ENSET Mohammedia.

The visual capture system relies on a fixed RGB camera mounted on a rigid support, positioned to observe the robot’s work area from different perspectives. To improve the robot’s robustness with respect to geometric variations and acquisition conditions, data was collected using several camera configurations corresponding to different observation angles of the scene.

To carry out our study, the following equipment was used and installed as shown in

Figure 2

:

  • ABB IRB1100 robot,

  • Cognex camera coupled to the robot

  • ZW LRCP FULL HD detection camera

FIGURE 2

3.1.2 Multi-angle acquisition

The dataset was constructed from several camera angles to reduce bias related to a single configuration and improve the generalization capacity of detection. We chose five main configurations:

  • Configuration 1 (C1)

Our initial configuration in which the camera is positioned above the robot at an inclined angle, with objective of capturing the spatial relationship between the robot and the work area.

  • Configuration 2 (C2)

Camera above the robot with the presence of a horizontal structural element (bars) visible above the operating area. This configuration aims to modify the visual context of the scene.

  • Configuration 3 (C3)

Camera positioned on a lateral support arm to introduce perspective variations.

  • Configuration 4 (C4)

Camera placed at a distance covering the entire scene to test robustness under real-world conditions.

  • Configuration 5 (C5)

In this configuration, controlled lighting variation has been introduced in order to study the effect of illumination conditions on object detection performances. The experimental conditions are: Reduced lighting and Enhanced lighting.

Details of these configurations will be given in the results Table 1.

TABLE 1

DatasetNumber of instancesRobot_in_operating_zoneRobot_in_restricted_zoneComment
C120349001134Each image contains one operating zone instance
C21297544814
C3300152148
C4300180120
C520015466
Total413119302201

Dataset distribution for all configurations.

3.1.3 Image extraction

Data was collected in the form of video sequences, captured during normal robot operation as well as in situations simulating an exit from the work area. The videos were then converted into still images using a temporal sampling process. The extraction pipeline includes the following steps:

  • Capture experimental videos;

  • Extract frames at constant intervals;

  • Filter out blurry or redundant images;

  • Organize images according to camera configuration.

This approach allows for the construction of a diverse dataset while limiting excessive temporal correlation between consecutive images.

To prevent data leakage due to temporal correlation between consecutive frames, we extracted frames at regular intervals to ensure sufficient variability between samples. We also filtered out visually similar consecutive frames to reduce redundancy.

Also, a strict separation between training, validation, and test sets was applied at the sequence level. This ensures that frames from the same video segment never appear in different subsets, preventing information leakage and allowing for a proper evaluation of the model’s generalization capabilities.

3.2 Annotation procedure

3.2.1 Purpose of the annotation

The annotation aims to identify the robot’s position relative to the work area, as shown in

Figure 3

, the chosen annotation strategy actually relies on three classes. This allows the model to develop true spatial reasoning:

  • Robot in the operating zone

  • Robot in a restricted area

  • Operating zone (reference boundary)

FIGURE 3

With this approach, the model doesn't just learn the robot’s state, it also understands the spatial relationship between the robot and its work area. Which is essential for reliable anomaly detection.

Table 2 shows a sample of the images collected.

TABLE 2

ClassesExample of images
Robot in work zone
Robot in restricted zone
Operating zoneThe yellow and black rectangle you see in the image represents the safety zone or the operation zone demarcated for the robot

Example of dataset.

3.2.2 Annotation tool

The annotations were performed using the ROBOFLOW platform, which allows for the annotation of bounding boxes, dataset management, and the automatic generation of shapes compatible with YOLO models.

3.2.3 Classes and annotation types

For data annotation, we used the segmentation method, for which we defined three classes, as shown in

Table 3

and

Figure 3

:

  • “Robot in work zone”: the robot is considered to be in the work zone when the end effector (tool at the end of the arm) of the robot and its axis are inside the zone;

  • “Robot in forbidden zone”: Images of the robot outside the work zone;

  • “Operating zone”: The boundary of the operating zone is marked in yellow with the ‘operating zone’ label.

TABLE 3

ID className of class
01Robot in operation zone
02Robot in restricted zone
03Operation zone

Details of classes.

The annotation type used is polygonal segmentation/bounding boxes.

3.3 Quality control

Manual quality control was performed on a subset of annotated images (10%–20%) to verify:

  • Label consistency;

  • Contour accuracy;

  • Homogeneity of annotations between images.

3.4 Training model

We used the segmentation architecture of the YOLO family:

  • YOLOv8n-seg

  • YOLOv11n-seg

Both models were trained under the same conditions to ensure a fair comparison.

For our initial configuration C1, according to the 70/15/15; we used a dataset of 1423 images for data training, 306 for model validation and 305 for test, as shown in Table 4. The same spilt is used for all configurations.

TABLE 4

DatasetsNumber of images
Training dataset1423
Validation dataset306
Test dataset305
Total2034

Dataset distribution for initial configuration C1.

3.5 Evaluation protocol

3.5.1 Standard evaluation (in domain)

The trained model was validated and tested according to the 70/15/15 breakdown. The calculated metrics are:

  • mAP@50–95;

  • mAP@50;

  • Accuracy;

  • Recall;

  • F1-score.

3.5.2 Cross-condition evaluation

The model is then evaluated on unseen and partially offered conditions to measure:

  • Sensitivity to angle changes;

  • Sensitivity to scene modifications;

  • Sensitivity to variations in brightness.

The conditions are compared to the reference configuration C1, to evaluate the relative degradation.

3.6 Reproducibility and availability

To improve transparency and reproducibility:.

  • Training, validation, and inference data are documented;

  • A fixed seed is used for experiments;

  • Parameters are provided in Table 5;

  • An anonymized subset of the dataset can be shared.

TABLE 5

BlocParametersValus
Model setupArchitectures, version ultralytics, pretrained weights, imgszYOLOv8n-seg/YOLOv11n-seg; ultralytics 8.4.14; COCO pretrained; 640 × 640
Training setupEpochs, batch, optimizer, LR, seed100, 200 and 300 epochs; batch = 16; SGD; lr = 0.01; seed = 42
AugmentationRotation, brightness/contrast, blur, mosaic±10°; ±20%; Gaussian blur p = 0.1; mosaic enabled
Evaluation and inferencemetrics, conf/IoU thresholds, GPU/CPUmAP50/mAP50-95/P/R/F1; conf = 0.25; IoU = 0.45; RTX 3060 + i7
AnnotationAnnotation protocol3 classes/polygons
AnnotationQuality controlDouble manual check (10%–20%)

Reproduction parameters of experiments.

To improve the diversity of the dataset and enhance the robustness and generalizability of the deep learning models, the dataset was augmented using standard data augmentation techniques. These techniques included random rotations, horizontal and vertical translations, scaling, brightness and contrast adjustments, and slight perspective transformations. Data augmentation was applied exclusively to the training set to prevent data leakage and ensure an objective evaluation of the model.

3.7 Presentation of YOLO models used

Model training has been carried out using the yolo versions family, namely, YOLOv8 and YOLOv11, which are designed to provide improved detection accuracy and computational efficiency, making them particularly suitable for real time industrial monitoring applications. YOLO based models follow a unified object detection framework capable of simultaneously performing object localization and classification within a single neural network architecture ().

Both YOLOv8 and YOLOv11 adopt a modular architecture composed of three main components: a backbone network, a neck module and a detection head, Figure 4. The backbone is responsible for extracting hierarchical visual features from the input image using convolutional layers and feature extraction blocks. In YOLOv8, the backbone architecture relies on an optimized Cross stage Partial (CSP) structure combined with advanced convolutional modules to improve feature representation while maintaining computational efficiency ().

FIGURE 4

The neck component aggregates multi sale features through a feature fusion strategy that typically combines a Feature Pyramid Network (FPN) and a Path Aggregation Network (PAN). This structure allows the model to integrate both low level spatial information and high-level semantic features, enabling robust object detection across different object scales and complex industrial scenes.

YOLOv11 represents a further evolution of the YOLO architecture and introduces several improvements in feature extraction and feature fusion mechanisms. In particular enhanced convolutional blocks such as the C3K2 module improve the efficiency of feature representation and enable more accurate detection of objects and structural details in complex environments. Furthermore, YOLOv11 integrates instance segmentation capabilities, allowing the model not only to detect objects using bounding boxes but also to generate pixel-level segmentation masks for each detected object. This enables more precise scene interpretation and facilitates advanced applications such as detailed object localization, spatial analysis and industrial monitoring tasks ().

Finally, the detection head of YOLOv8 and YOLOv11 performs the final prediction stage by estimating class probabilities, bounding bx coordinates and confidence scores based on the extracted features/in segmentation mode, the model additionally predicts object masks, enabling fine grained representation of objects within the monitoring environment.

3.8 Decision rule for zone violation detection

In our approach, zone violation detection relies not only on the predicted class label but also on spatial reasoning derived from the segmentation results. Thus, our decision mechanism is based on the geometric relationship between the robot and the operating zone. To this end, in our study, a violation is detected when the spatial overlap between the robot’s segmentation mask and the operational area mask is less than a predefined threshold τ. Thus, we empirically set the value of τ to 0.7 which offers a balanced compromise between sensitivity to area violations and robustness to segmentation noise.

In practice, the system evaluates whether the end effector, its axis, and a significant portion of the robot’s structure lie outside the predefined zone polygon. If this condition is met, an alert indicating a potential anomaly requiring intervention is generated.

4 Results

The objective of our research is to present a new monitoring framework based on real-time monitoring for proactive maintenance of robots in industrial environments. Thus, based on YOLO architectures, the system studied enables real-time detection of the position of industrial robots and verifies their spatial compliance with the recommended work areas. This approach offers visual geolocation, enabling immediate alerts to be triggered when a robot is located outside its designated workspace. Figure 7 explains the approach used in more detail.

4.1 Standard evaluation in domain

4.1.1 Yolov8 results

Initially, the model training is based on YOLOv8. The results of this training are shown in the Table 6 and Figure 5 which provide the model values for four parameters: precision, recall, mAP50, and mAP50-95 for bounding boxes and segmentation masks.

TABLE 6

MetricYolov8
Precision box0,9685
Recall box0,95874
mAP50 box0,98914
mAP5095 box0,87105
Precision mask0,89292
Recall mask0,87398
Mask_Map500,89524
mAP5095 mask0,7143

YOLOV8 metrics results.

FIGURE 5

The results show that the YOLOv8 model used achieves excellent results in bounding box detection and good performance in mask segmentation.

In fact, for bounding boxes, the model’s accuracy is 96.85%, which shows that the vast majority of detections are correct and with very few false positives. For recall, it reached 95.87%, which means that the model manages to detect almost all objects present. In addition, the mAP50 metric is high, recording a value of 98.91%, which means a good ability to locate objects at an IoU threshold of 0.5. Even with stricter criteria (mAP50-95 at 87.10%), performance remains very solid, confirming accurate and reliable localization.

On the other hand, with regard to segmentation masks, the model’s accuracy is 89.29% and its recall is 87.40%, which shows that the model correctly segments most objects while covering a large part of their actual surface area. In addition, the mAP50 is 89.52%, which is lower than the values obtained for bounding boxes. However, the mAP50-95 is lower (71.43%), revealing a drop in performance when segmentation must be very precise on the contours or fine details of objects.

4.1.2 Yolov11 results

The second phase of our research consists of using the YOLOv11 model in segmentation mode and adjusting the hyperparameters.

To this end, we have chosen two hyperparameters that are likely to influence the performance and results of the model. These two hyperparameters are: the number of training epochs and the learning rate.

Thus, the number of epochs is the number of times the entire training dataset is completely traversed by the model. We selected 100, 200, and 300 epochs.

On the other hand, the learning rate determines the extent of the adjustments made to the weights of the neural network at each iteration of the optimization. In this case, we chose the following values: (lr = 0.01, 0.001, and 0.0001).

Thus, Tables 7, 8 show samples of images illustrating the detection of robots in their work area and in the restricted area obtained by the two models at different training times.

TABLE 7

Detection model100 epoch200 epoch300 epoch
YOLOv8
YOLOv11

Sample of robot results in the work area.

TABLE 8

Detection model100 epoch200 epoch300 epoch
YOLOv8
YOLOv11

Sample of robot results in the restricted area.

Table 9 and Figure 6 summarize the values of the mAP50, mAP50-95, precision, recall, F1-score, and FPS metrics for the two models according to the different epochs and learning rates.

TABLE 9

ConfigurationModelmAP50mAP50-95PrecisionRecallF1-scoreFPS
100 epochs (lr = 0,01)YOLOv899.13%88.00%97.74%96.19%96.96%∼92
YOLOv1198.81%86.16%95.41%97.50%96.45%∼92
200 epochs (lr = 0,001)YOLOv899.05%88.34%98.32%95.19%96.73%∼90
YOLOv1199.17%87.29%97.90%96.93%97.41%∼90
300 epochs (lr = 0,0001)YOLOv899.05%88.34%98.32%95.19%96.73%∼88
YOLOv1199.08%87.28%98.03%94.90%96.44%∼88

Comparison of YOLOV8 and YOLOV11.

FIGURE 6

An overall reading of the results shows that both the YOLOv8 and YOLOv11 models perform very well in all configurations, with mAP50 values above 98% and F1 scores between 96% and 97%. This performance indicates excellent accuracy and very good recall. It is also worth noting that the differences in performance are small, indicating that the two architectures are competitive.

Furthermore, the results of the configuration comparison are as follows:

First, after training for 100 epochs with lr = 0.01, the results show that YOLOv8 achieves a slightly higher mAP50 (99.13% vs. 98.81% for YOLOv11) and a higher mAP50-95. However, YOLOv11 compensates with a stronger recall (97.50% vs. 96.19%), indicating that it detects slightly more objects with a few more false positives. The FPS remains the same (∼92), showing that speed is not impacted by the model.

Next, at 200 epochs and Lr = 0.001, we see that YOLOv11 takes the lead on mAP50 (99.17%) and maintains a good balance between precision and recall. Meanwhile, YOLOv8 remains very close with an mAP50 of 99.05%, but has slightly higher accuracy. For FPS and F1-score, the two models are almost identical.

Finally, at 300 epochs and lr = 0.0001, we observe that performance is stable, which shows that increasing the number of epochs at a low learning rate does not bring any notable gain. The two models are almost equivalent. Also, FPS remains the same (∼88), confirming that speed depends more on hardware configuration than on architecture or the number of epochs.

The analysis of results and taking into account the objective is to monitor whether a robot is within its working area. The main risk is triggering a false alarm (saying that the robot is out of range when it is still within range). In this type of mission, we are looking for fewer false alarms, which means higher accuracy. It is preferable to be sure before triggering an alarm, even if this sometimes means missing a borderline case. According to the results, YOLOv8 always has a slightly higher or equivalent accuracy to YOLOv11, especially at 100 epochs (+2.33% difference).

When it comes to a security system, a false positive can cause unnecessary shutdowns, waste time, and even disrupt production. YOLOv8 is therefore more reliable for confirming an out-of-zone event, as it makes fewer false alarms.

In summary, the results show that YOLOv8 and YOLOv11 display consistent performance for all cases, where there are slight differences with regards to the values of metrics used for evaluation. From a broader view, In the case of YOLOv8, the model shows better localization while YOLOv11 performs similarly well in terms of recall. Generally speaking, Considering the negligible difference in performance and lack of statistical test between YOLOv8 and YOLOv11, the choice of using YOLOv8 for the upcoming experiment can be attributed to its slight consistency advantage.

Based on the comparative evaluation of YOLOv8 and YOLOv11, YOLOv8 trained for 200 epochs was selected as the final model for the cross-validation experiments.

4.2 Cross -view and cross-condition evaluation

In this section, the objective is to rigorously evaluate the performance and generalization capability of the proposed monitoring system. So, we conducted a series of cross-view experiments based on the experimental protocol defined in the previous section. While the dataset construction and training pipeline were previously described, the objective of the following experiments is to assess the robustness of the trained model under different operational conditions.

To address this challenge, a set of controlled experiments was designed using multiple combinations of training and testing datasets collected from different configurations viewpoints (C1, C2, C3, and C4). These experiments allow us to evaluate several aspects of the model performance, including baseline in-domain accuracy, robustness to multi-view conditions, generalization to partially or fully unseen viewpoints and sensitivity to illumination changes. Tables 1012 give a sample of these datasets.

TABLE 10

C1C2

Example of dataset for C1 and C2.

TABLE 11

C3C4

Example of dataset for C3 and C4.

TABLE 12

C5: Enhanced lightingC5: Reduced lighting

Example of dataset for C5 enhanced lighting. And reduced lighting.

The different experiments for cross-view and cross-condition evaluation are summarized in Table 13.

TABLE 13

ExperimentTraining setTest setObjective
E1C1C1 testBaseline in-domain performance
E2C1 + C2C1 test + C2 testMulti-view
E3C1 + C2 + 20% C3 + 20% C480% C3Robustness to partially seen viewpoint shift
E4C1 + C2 + 20% C3 + 20% C480% C4Generalization to another partially seen viewpoint
E5C1C2 testGeneralization to an unseen viewpoint
E6a - brightC1 + C2 + 20% C3 + 20% C4C5 light variantsIllumination robustness
E6b DarkC1 + C2 + 20% C3 + 20% C4C5 dark variantsIllumination robustness

The different experiments configurations used for cross-view and cross-condition evaluation.

We organized the experiments according to increasing levels of difficulty as follows: first a basic evaluation in the domain (E1), followed by multi-view training scenarios (E2–E4), and finally inter-view generalization tests and evaluation of lighting robustness (E5–E6a-E6b).

The datasets for each experiment are given in the Tables 14.

TABLE 14

DatasetsE1E2E3E4E5E6a/E6b
Training dataset142323322452245214232452
Validation dataset306400400400606400
Test dataset305194240240600200
Total203429263092309226293052

Dataset repartition by experiments.

4.2.1 Overall analysis of results obtained

The results in Table 15, the experiments E1-E6; allow us to rigorously evaluate the performance of the YOLO V8 model in several representative industrial deployment scenarios, including intra-domain validation, Multiview learning, generalization to partially observed views, generalization to a completely unobserved view, and robustness to photometric variations:

TABLE 15

ExperimentTraining setTest setBox precisionBox recallBox mAP@50Box mAP@50–95Mask precisionMask recallMask mAP@50Mask mAP@50–95
E1C1C1 test0.9770.9680.9910.8960.9730.9640.9900.840
E2C1 + C2C1 + C2 test0.9800.9730.9900.9110.9800.9730.9890.857
E3C1 + C2 + 20% C3 + 20% C480% C30.9260.8110.7780.6800.8750.7890.7490.593
E4C1 + C2 + 20% C3 + 20% C480% C40.8970.9580.9380.8850.8970.9580.9380.756
E5C1C2 test0.7360.4880.5700.2990.7230.4740.5510.206
E6aC1 + C2 + 20% C3 + 20% C4C1 bright test0.9570.9660.9870.8920.9570.9660.9870.836
E6bC1 + C2 + 20% C3 + 20% C4C1 dark test0.9720.9490.9790.8820.9720.9490.9790.821

Results of cross-view and cross-condition evaluation.

Using formula 1, we calculated the performance loss experimentally.

In general, the result s in Tables 1517 highlight three major findings:

TABLE 16

ExperimentBox mAP@50–95Performance drop (%)Objective
E10.8960%Baseline in-domain performance
E20.911−1.7% (win)Performance on seen multi-view conditions
E30.68024.1%Robustness to partially seen viewpoint shift
E40.8851.2%Generalization to another partially seen viewpoint
E50.29966.6%Generalization to an unseen viewpoint
E6a0.8396.4%Robustness to illumination changes

Performance drop.

TABLE 17

E2
E3
E4
E6a/E6b

Sample of cross-view and cross-condition evaluation results.

First, the model exhibits excellent performance under conditions close to the training domain; Second, the diversity of viewpoints during training significantly improves robustness; Third, generalization to a completely unobserved view remains the main limiting factor, even more so than variations in lighting.

4.2.2 Analysis by experiment

4.2.2.1 The intradomain reference performance E1

E1 results are very high:

  • Box mAP@50 = 0.991;

  • Box mAP@50–95 = 0.896;

  • Mask mAP@50 = 0.990;

  • Mask mAP@50–95 = 0.840.

These results show that the model correctly learns the geometric structure of the scene, the robot’s position, and the boundary of the operating area. The model does not suffer from an excess of false positives or a major detection deficit effect in this context.

4.2.2.2 Observed multiview learning E2

Experiment E1 extends learning to C1+C2. The results remain excellent, with a slight improvement on certain metrics:

  • Box mAP@50 = 0.990;

  • Box mAP@50–95 = 0.911;

  • Mask mAP@50 = 0.989;

  • Mask mAP@50–95 = 0.857.

These results show that introducing a second view does not degrade learning, but on the contrary, improves the model’s ability to produce more robust localizations across several IoU thresholds. This experiment therefore validates a key hypothesis: that Multiview learning improves robustness without compromising nominal performance.

4.2.2.3 Generalization to partially observed views

Experiments E3 and E4 evaluate the model in an intermediate situation. Views C3 and C′ are not completely unknown; a small proportion of images from these views are included in the training.

–E3, test on C3

Thus, E3, tested on C3, shows a clear drop in performance:

  • Box mAP@50 = 0.778;

  • Box mAP@50–95 = 0.680;

  • Mask mAP@50 = 0.749;

  • Mask mAP@50–95 = 0.593.

This indicates that view C3 introduces a more significant visual break compared to C1 and C2, encompassing several factors: perspective variation, modification of the robot’s relative appearance, and a change in proportion between the robot and the area.

–E4 test on C4

Unlike C3, the results are good:

  • Box mAP@50 = 0.938;

  • Box mAP@50–95 = 0.885;

  • Mask mAP@50 = 0.938;

  • Mask mAP@50–95 = 0.756.

Thus, the contrast between E3 and E4 is scientifically very interesting. While both experiments are based on the same methodological principle, C4 is clearly closer to the learning domain than C3. This means that not all variations in perspective have the same impact on performance.

4.2.2.4 Strict generalization to a completely unobserved view E5

The E5 experiments are probably one of the most important. The model is trained only on C1 and then tested on C5, which constitutes a completely unobserved view. The performance drops sharply:

  • Box mAP@50 = 0.570;

  • Box mAP@50–95 = 0.299;

  • Mask mAP@50 = 0.552;

  • Mask mAP@50–95 = 0.206.

This decrease demonstrates that the model, when trained on a single perspective, develops a representation that is too specific from a training perspective. In practice, this means that the excellent performance of E1 does not guarantee robust deployment capabilities in a variable environment.

Thus, E5 confirms the existence of a strong viewpoint effect. This justifies the need for:

  • Multiview learning,

  • Vertical cross-validation,

  • Possibly future approaches to domain adaptation.

Thus, E5 highlights the structural limitations of single-view learning and reinforces the credibility of the experimental protocol we established.

4.2.2.5 Robustness to photometric variations

The E6 experiments (dark and bright) evaluate the model’s sensitivity to low and high light conditions. The results are generally high for both tests:

  • Box mAP@50 = 0.987;

  • Box mAP@50–95 = 0.839;

  • Mask mAP@50 = 0.902

  • Mask mAP@50–95 = 0.721.

These results show that the model is significantly more robust to photometric variation than to a strong geometric viewpoint, as the E6 results are considerably superior to the E3 and especially the E5 results.

Thus, this result is important, meaning that the system could maintain acceptable performance in an environment with reduced or strong lighting, provided that the geometric configuration remains close to that known during training.

4.2.3 Conclusion

Based on the results, the conclusion of this section is as follows:

  • First, the proposed YOLOv8 model performs highly under the observed intra-domain and multi-view conditions, with very high performance for E1 and E2.

  • Then, Experiments E3 and E4 demonstrate that the partial introduction of new views during training improves generalization capacity, although this improvement is highly dependent on the similarity between the test view and the training views.

  • However, experiment E5 highlights the major difficulty of generalization to a completely unobserved view, emphasizing the critical role of viewpoint bias.

  • Finally, E6-dark/light confirms that the model remains generally robust to lighting variations, with a more pronounced impact on segmentation than on detection

5 Discussion

5.1 Results summary

The experimental analysis first compared two recent object detection architectures namelyYOLOv8 and YOLOv11, to identify the most suitable model for the proposed robotic monitoring system. Both models achieved very high detection performance. With mAP50 values exceeding 98%. However, using the more demanding mAP50-95 metric, YOLOv8 exhibits slightly higher localization accuracy (88.34%) than YOLOv11 (87.29%). Furthermore, YOLOv8 demonstrated greater stability across training configurations while maintaining a similar inference speed. Therefore, YOLOv8, trained for 200 epochs, was selected for subsequent experiments.

Cross-view and cross-condition evaluation experiments were conducted to evaluate the robustness and generalizability of the proposed monitoring framework under different viewpoints and lighting conditions. The baseline experiment E1 confirms excellent performance in this area, with a mAP50 of 0.991 and a mAP50-95 of 0.86. When multiple viewpoints were included in the training E2, the model maintained stable performance and slightly improved accuracy indicating that Multiview learning enhanced robustness.

Experiments involving partially observed viewpoints E3 and E4 showed that model performance depends on the geometric similarity between viewpoints, with better results obtained on viewpoint C4 than on C3.

The strict viewpoint comparison experiments where the model was trained on C1 and tested on the unknown viewpoint C2, revealed a significant drop in performance, highlighting the strong influence of viewpoint bias in vision surveillance systems.

Finally, the lighting experiment E6 demonstrated that the model remains relatively robust in low-light conditions. Although segmentation accuracy decreases slightly, overall detection performance remains high. These results indicate that variations in viewpoint have a greater impact on system performance than variations in lighting.

Overall, the proposed monitoring system achieves high detection accuracy while maintaining reasonable robustness in the face of diverse viewpoints and environmental conditions.

5.2 Scientific and research contributions

Our research combines computer vision, predictive maintenance, and industrial robotics, with a particular focus on spatial monitoring of robots using AI. The main scientific contributions of this study can be summarized as follows:

  • Development of a vision-based monitoring framework for industrial robotic workspaces:

Our work proposes a computer vision-based monitoring system capable of detecting the position of an industrial robot relative to predefined operating and restricted zones. The proposed framework enables real-time supervision of robotic workspaces, contributing to improved operational safety and maintenance monitoring in industrial environments.

Figure 7

illustrates the proposed framework.

  • Comparative evaluation of recent object detection architectures for robot monitoring.

FIGURE 7

The study provides a systematic comparison between two recent deep learning architectures, YOLOv8 and YOLOv11 in the context of industrial robot monitoring. The results demonstrate that YOLOv8 achieves slightly better localization accuracy and training stability while maintaining real-time inference performance.

  • Construction of a Multiview robotic workspace dataset.

A dataset was developed using multiple camera viewpoints capturing the industrial robot workspace from different perspectives. This dataset allows the evaluation of vision-based monitoring systems under varying geometric configurations and supports the analysis of viewpoint-related challenges in robotic monitoring tasks.

  • Introduction of a cross-view validation protocol for industrial vision systems.

A comprehensive cross-view and cross-condition evaluation framework was designed to evaluate the robustness of the monitoring system across multiple viewpoints and illumination conditions. The proposed protocol includes baseline evaluation, multi-view training experiments, strict cross-view generalization tests, and illumination robustness analysis.

  • Experimental analysis of viewpoint bias in robot monitoring systems.

The experimental results highlight the strong influence of viewpoint variations on detection performance. In particular, the strict cross view experiment reveals a significant performance drop when the model is trained on a single viewpoint, emphasizing the importance of multi-view training for reliable deployment in industrial environments.

Overall, these contributions provide practical and methodological insights for the development and evaluation of vision-based monitoring systems for industrial robotic applications.

5.3 Limitations

Despite the promising results obtained in this study, several limitations should be acknowledged.

First, the dataset used in this work is limited to a specific robotic workspace and a relatively controlled industrial environment.

Although multiple viewpoints were considered, the diversity of environmental conditions remains limited compared with real-world industrial deployments.

Second, the system relies primarily on visual information captured by fixed cameras. In highly dynamic environments, occlusions or complex background structures may affect detection performance.

Third, although segmentation capabilities were evaluated, the current framework focuses primarily on object detection rather than precise robot pose estimation or motion prediction.

6 Conclusion

This study focuses on the application of AI to optimize robot detection and maintenance interventions in industrial environments. Based on the YOLO v8 and YOLO v11 models, we have developed a real-time detection system that monitors the operational states of robots in predefined zones. The results show that both models deliver excellent performance, with YOLO v8 and YOLO v11 achieving high values of mean accuracy and impressive measures of recall and precision over different epochs. YOLO v8, in particular, shows consistent improvement with increasing training epochs, while YOLO v11 also delivers robust performance despite a slight dip at intermediate epochs. The Cross-validation experiments have also revealed that Multiview training significantly improves detection robustness, while rigorous cross-assessments highlight the significant influence of viewpoint variations on model performance. In contrast, lighting variations have a comparatively smaller impact on detection accuracy.

This research highlights the potential of AI-driven solutions to improve maintenance efficiency; by enabling automated detection of zone violations and abnormal robot positions, the proposed framework helps to reduce safety risks and improve operational efficiency in industrial environments.

Nevertheless, several challenges remain for large-scale deployment, including the diversity of datasets, robustness in the face of complex environmental conditions, and computational constraints for real-time processing. Future research will focus on integrating multisensory data, exploring domain adaptation techniques to improve cross-environment generalization, and extending the framework to predictive maintenance by integrating temporal analysis of robot behavior.

Statements

Data availability statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Author contributions

ML: Writing – original draft, Software, Formal Analysis, Resources, Data curation, Visualization, Methodology. ME-C: Supervision, Writing – review and editing, Project administration, Validation. SN: Writing – review and editing, Supervision, Project administration, Resources, Validation. ME: Writing – original draft, Resources, Methodology. MH: Supervision, Writing – review and editing, Software, Resources.

Funding

The author(s) declared that financial support was not received for this work and/or its publication.

Acknowledgments

The authors would like to express their sincere gratitude to the Director of ENSET Mohammedia for their continuous support and to the M2S2I Laboratory for providing technical support, including access to laboratory facilities and the use of available research resources. This non-financial support contributed to the successful completion of the experimental work.

Conflict of interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declared that generative AI was not used in the creation of this manuscript.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmech.2026.1806266/full#supplementary-material

References

  • 1

    AlayedA.AlidrisiR.FerasE.AboukozzanaS.AlomayriA. (2024). Real-time inspection of fire safety equipment using computer vision and deep learning. Eng. Technol. Appl. Sci. Res.14 (2), 1329013298. 10.48084/etasr.6753

  • 2

    CarvalhoT. P.SoaresF. A. A. M. N.VitaR.FranciscoR. da P.BastoJ. P.AlcaláS. G. S. (2019). A systematic literature review of machine learning methods applied to predictive maintenance. Comput. Ind. Eng.137, 106024. 10.1016/j.cie.2019.106024

  • 3

    DhandaM.RogersB. A.HallS.DekoninckE.DhokiaV. (2025). Reviewing human-robot collaboration in manufacturing: opportunities and challenges in the context of industry 5.0. Robot. Comput.-Integr. Manuf.93, 102937. 10.1016/j.rcim.2024.102937

  • 4

    DuiH.XuH.ZhangL.WangJ. (2023). Cost-based preventive maintenance of industrial robot system. Reliab. Eng. Syst. Saf.240, 109595. 10.1016/j.ress.2023.109595

  • 5

    GuoB. H. W.ZouY.FangY.GohY. M.ZouP. X. W. (2021). Computer vision technologies for safety science and management in construction: a critical review and future research directions. Saf. Sci.135, 105130. 10.1016/j.ssci.2020.105130

  • 6

    HüttenN.Alves GomesM.HölkenF.AndricevicK.MeyesR.MeisenT. (2024). Deep learning for automated visual inspection in manufacturing and Maintenance: a survey of Open- access papers. Appl. Syst. Innov.7 (1), 11. 10.3390/asi7010011

  • 7

    KiranaN. L.KurnianingtyasD.Indriati (2024). A deep learning approach to plastic bottle waste detection on the water surface using YOLOv6 and YOLOv7. Eng. Technol. Appl. Sci. Res.14 (6), 1862318630. 10.48084/etasr.8592

  • 8

    LeCunY.BengioY.HintonG. (2015). Deep learning. “Deep Learning,” Nat.521 (7553), 436444. 10.1038/nature14539

  • 9

    LirongL.HaoC.JunweiD.BingM.ZhijieZ.ZhangqinH.et al (2025). High-voltage transmission line inspection based on multi-scale lightweight convolution. Measurement.251. 117193. 10.2139/ssrn.4861628

  • 10

    MehadjbiaA.Slaoui-HasnaouiF. (2025). “Structural damage detection of wind turbine based on YOLO11,” in 5th International Conference on Innovative Research in Applied Science, Engineering and Technology (IRASET). Fez, Morocco: IEEE,2025. 16. 10.1109/IRASET64571.2025.11008148

  • 11

    RajamohananR.LathaB. C. (2023). An optimized YOLO v5 model for tomato leaf disease classification with field dataset. Eng. Technol. Appl. Sci. Res.13 (6), 1203312038. 10.48084/etasr.6377

  • 12

    RedmonJ.DivvalaS.GirshickR.FarhadiA. (2016a). You only look once: unified, real-time object detection. arXiv arXiv:1506.02640. 10.48550/arXiv.1506.02640

  • 13

    RedmonJ.DivvalaS.GirshickR.FarhadiA. (2016b). “You only look once: unified, real–time object detection,” in 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 779788. 10.1109/CVPR.2016.91

  • 14

    SaranyaE.NivethaR.AbiramiS.Mohaideen ArsathM.DharaneeshS. (2024). “Revolutionizing road maintenance: YOLO based pothole detection system,” in 2024 10th International Conference on Advanced Computing and Communication Systems (ICACCS), 19911997. 10.1109/ICACCS60874.2024.10716937

  • 15

    SongJ.ChengK.ChenF.HuaX. (2025). RDW-YOLO: a deep learning framework for scalable agricultural Pest monitoring and control. Insects16 (5), 545. 10.3390/insects16050545

  • 16

    SoudaniM. L.NissabouriS.Ech-ChhibatM. E. H. (2024a). “Maintenance and production optimization using artificial intelligence (AI) tools: a bibliometric analysis and review,” in 2024 4th International Conference on Innovative Research in Applied Science, Engineering and Technology (IRASET), 18. 10.1109/IRASET60544.2024.10549204

  • 17

    SoudaniM. L.NissabouriS.Ech-ChhibatM. E. H. (2024b). Artificial intelligence for maintenance and production optimization: applications, techniques and challenges. Int. Rev. Mech. Eng. IREME18 (11), 577. 10.15866/ireme.v18i11.25151

  • 18

    SoudaniM. L.NissabouriS.Ech-ChhibatM. E. H.HaidouryM.ElhirchI. (2025). “Industrial robots and collaborative robots: a comparative study,” in 2025 5th International Conference on Innovative Research in Applied Science, Engineering and Technology (IRASET), 110. 10.1109/IRASET64571.2025.11008132

  • 19

    SoumyadeepM.SinghA. P.SharmaA.KumarP. (2023). “Real-time object detection and tracking using deep learning,” in 2023 11th International Conference on Intelligent Systems and Embedded Design (ISED), 17. 10.1109/ISED59382.2023.10444534

  • 20

    Ultralytics (2026). Explore ultralytics YOLOv8. Available online at: https://docs.ultralytics.com/models/yolov8/(Accessed March 08, 2026).

  • 21

    WangK.ZhangX.SunY.XuT.LiJ.CaoS. (2024). YOLO-DFT: an object detection method based on cloud data fusion and transfer learning for power system equipment maintenance. IET Collab. Intell. Manuf.6 (2), e12104. 10.1049/cim2.12104

  • 22

    WangL.ZhangG.WangW.ChenJ.JiangX.YuanH.et al (2024). A defect detection method for industrial aluminum sheet surface based on improved YOLOv8 algorithm. Front. Phys.12 (Jun), 1419998. 10.3389/fphy.2024.1419998

  • 23

    ZhanfangZ.TuoL. (2025). Enhancing wind turbine blade damage detection with YOLO-wind. Sci. Rep.15 (1), 18667. 10.1038/s41598-025-03639-8

  • 24

    ZhaoR.TangS. H.ShenJ.SupeniE. E. B.RahimS. A. (2024). Corrigendum to ‘enhancing autonomous driving safety: a robust traffic sign detection and recognition model TSD-YOLO’. Signal Process.225, 109619. 10.1016/j.sigpro.2024.109619

  • 25

    ZontaT.da CostaC. A.da Rosa RighiR.de LimaM. J.da TrindadeE. S.LiG. P. (2020). Predictive maintenance in the industry 4.0: a systematic literature review. Comput. Ind. Eng.150, 106889. 10.1016/j.cie.2020.106889

  • 26

    ZouX. (2019). “A review of object detection techniques,” in 2019 International Conference on Smart Grid and Electrical Automation (ICSGEA), 251254. 10.1109/ICSGEA.2019.00065

Summary

Keywords

deep learning, object detection, optimization industrial robotics, predictive maintenance, YOLO V8, YOLOv11

Citation

Lamine Soudani M, Ech-Chhibat MEH, Nissabouri S, El khiate M and Haidoury M (2026) Automated control of robots in the work zone: a YOLO-Based approach for optimized maintenance. Front. Mech. Eng. 12:1806266. doi: 10.3389/fmech.2026.1806266

Received

07 February 2026

Revised

26 April 2026

Accepted

27 April 2026

Published

19 May 2026

Volume

12 - 2026

Edited by

Lien Thi Vu, Phenikaa University, Vietnam

Reviewed by

Viet Q. Vu, Thai Nguyen University of Technology, Vietnam

Muhammad Umar Elahi, Dongguk University, Republic of Korea

Updates

Copyright

*Correspondence: Mohamed Lamine Soudani,

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

Outline

Figures

Cite article

Copy to clipboard


Export citation file


Share article

Article metrics