Contactless Temperature Measurement and Quality Inspection of Solar Panels Using Cleaning Robots

Optris Xi 400 and Xi 410 provide thermal image data for automated inspection processes in the solar industry

Challenge

Contamination and defects in solar panels reduce energy generation and require regular cleaning and quality inspections. Inspecting large areas is time-consuming. Solar radiation and reflections make reliable defect detection using stationary thermal imaging cameras difficult. At the same time, cleaning robots must efficiently coordinate their movement paths and precisely locate potentially defective solar modules.

Solution

Optris thermal imaging cameras integrated into cleaning robots enable contactless temperature measurement during automated solar panel cleaning. The captured thermal images reveal thermal anomalies and are linked to the robots’ position data. This creates a thermal map of the solar installation that locates potentially defective panels, optimizes cleaning routes, and supports targeted maintenance activities.

Benefits

Early detection of thermal anomalies enables targeted maintenance and reduces potential energy yield losses.
Combining cleaning and quality inspection reduces the need for separate inspection processes.
Thermal mapping facilitates precise localization of abnormal solar panels across large installations.
Optimized movement profiles prevent unnecessary repeated passes, reducing cleaning times and energy consumption.
Continuous temperature monitoring supports water distribution assessment and identifies potential cleaning nozzle malfunctions.

Temperature Deviations as Indicators of Defective Solar Modules

Solar installations are continuously exposed to changing environmental conditions. Dust, sand, bird droppings, and other deposits contaminate the surfaces of solar panels and reduce their energy yield. At the same time, damaged solar cells, electrical contact problems, or other defects can cause localized temperature increases. Operators of large photovoltaic installations therefore face the challenge of regularly cleaning extensive module surfaces while simultaneously inspecting their technical condition. Particularly in large-scale installations, both tasks require considerable time and organizational effort.

Automated cleaning robots perform the cleaning process by moving across inclined module surfaces and removing contamination using integrated cleaning systems. Following a controlled movement profile, the robots systematically traverse the solar panels. An additional infrared camera makes it possible to capture thermal information during this process and visualize abnormal temperature distributions. Localized temperature increases may indicate so-called hotspots, which require further quality inspection of individual modules.

Contactless infrared temperature measurement presents particular challenges regarding measurement conditions. Solar radiation and reflections on glass surfaces can influence measurement results. At the same time, the applied cleaning water temporarily changes the surface temperature, making it difficult to distinguish between actual defects and temperature deviations caused by the cleaning process. Residual contamination can also distort the thermal assessment.

Appropriate positioning of the thermal imaging camera within the cleaning robot reduces interfering reflections and enables reproducible measurement of the module surfaces. It is also essential to synchronize the measurement timing with the cleaning process.

In addition to defect detection, the spatial assignment of measurement data plays an important role. Linking the captured thermal images with the cleaning robot’s position data provides the basis for thermal mapping of the solar installation. This supports both the targeted localization of abnormal solar panels and the optimization of cleaning routes. The process therefore combines automated surface cleaning with additional data-driven condition assessment.

Contactless Infrared Temperature Measurement with the Optris Xi 400 and Xi 410

The compact Optris Xi 400 and Xi 410 thermal imaging cameras are well suited for integrating contactless temperature measurement into automated cleaning robots. Both IR cameras capture the temperature distribution across the solar panel surfaces and provide radiometric thermal images for subsequent quality inspection. The cameras are positioned inside the robot to provide a viewing angle as close to perpendicular to the module surface as possible, minimizing interfering reflections and the influence of cleaning water.

The Optris Xi 400 features an optical resolution of 382 × 288 pixels and achieves frame rates of up to 80 Hz. This makes it particularly suitable for detailed thermal imaging while the robot is moving. The Xi 410 offers a resolution of 384 × 240 pixels and enables the transmission of radiometric image data via Ethernet at 25 Hz. Both infrared cameras operate in the spectral range of 8 to 14 µm and offer temperature measurement ranges suitable for this application, from −20 to 100 °C and 0 to 250 °C, respectively.

The Xi 410 additionally supports autonomous operation with integrated hotspot detection and direct alarm outputs. Power over Ethernet enables data transmission and power supply over distances of up to 100 meters using suitable cables.

Thermal image analysis is performed using the license-free Optris PIX Connect software or by integrating the image data into the robot control system through a Software Development Kit (SDK). Temperature values from individual pixels are synchronized with the robot’s movement data. Additional positioning information from visual cameras or LiDAR sensors enables spatial assignment of the captured images.

By combining individual thermal images through software processing, a comprehensive thermal overview map of the solar installation is created. This map displays temperature distributions and abnormal solar panels according to their positions. At the same time, the cleaning robot’s movement profile can be documented to identify areas that have already been processed and avoid unnecessary repeated passes. In this way, Optris infrared temperature measurement enhances the cleaning process with integrated thermal quality control.

Higher System Availability Through Automated Thermal Quality Inspection

The combination of automated cleaning and contactless temperature measurement provides solar installation operators with additional opportunities for condition monitoring. While the cleaning robot cleans the module surfaces, the integrated Optris thermal imaging camera provides thermal information about abnormal temperature distributions. This allows potentially defective solar panels to be identified at an early stage and subjected to targeted further inspection. Position-based data acquisition makes it possible to locate affected modules more quickly within large solar farms and plan maintenance activities more efficiently.

A key advantage comes from combining the thermal images into a comprehensive thermal overview map. This visualizes the temperature distribution across the solar installation and documents abnormal areas. At the same time, the recorded movement profile supports systematic navigation of the cleaning robot. Areas that have already been cleaned can be taken into account, reducing unnecessary repeated passes and helping optimize cleaning times and energy consumption.

With the Xi 400 and Xi 410, Optris offers compact, industrial-grade infrared cameras that can be integrated into existing robot designs with minimal space requirements, thanks to their small dimensions of approximately 36 mm in diameter and 100 mm in length. The IP67 protection rating supports operation under demanding environmental conditions. The different integration options are particularly beneficial: while the Xi 400 provides high frame rates for detailed analysis, the Xi 410 additionally enables autonomous temperature monitoring with direct signal output.

The license-free PIX Connect software and available SDK interfaces simplify integration into customized control and analysis systems. This allows thermal quality inspection to be adapted to different robot concepts.

For further optimization, Optris offers additional accessories such as air purge attachments, protective shields, and water-cooling housings. When appropriately configured, these components help protect the camera optics against contamination and demanding environmental conditions. In addition, monitoring temperature-related changes during cleaning enables assessment of water distribution and the detection of potentially malfunctioning cleaning nozzles. The result is a scalable solution that combines cleaning, condition monitoring, and process optimization.

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Talk to us about your IR Temperature Measurement Requirements

There are over 300 different pyrometer variants to choose from in the Optris infrared pyrometer portfolio each optimized for material, spot size, distance from the target, and environmental conditions. Fortunately, there is a trained engineer to phone or chat with to guide you through the process of choosing the perfect infrared sensor for your application.

The same support is available for the extensive IR camera product line.

Contactless Temperature Measurement and Quality Inspection of Solar Panels Using Cleaning Robots

Challenge

Solution

Benefits

Temperature Deviations as Indicators of Defective Solar Modules

Contactless Infrared Temperature Measurement with the Optris Xi 400 and Xi 410

Higher System Availability Through Automated Thermal Quality Inspection

Recommended Products

Xi 400 LT USB

Xi 410 LT ETH

Other Solar Applications

Crucial Role of Temperature Sensing in Accurate Solar Cell Flash Testing

Solar Cell Manufacturing: Thermal Quality Checks for Soldering & Tabbing

Steady State Thermography for Non-Intrusive Solar Module Defect Detection

Weak Shunt Identification in Solar Cells Production with Infrared Cameras

Talk to us about your IR Temperature Measurement Requirements

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Contactless Temperature Measurement and Quality Inspection of Solar Panels Using Cleaning Robots

Challenge

Solution

Benefits

Temperature Deviations as Indicators of Defective Solar Modules

Contactless Infrared Temperature Measurement with the Optris Xi 400 and Xi 410

Higher System Availability Through Automated Thermal Quality Inspection

Recommended Products

Xi 400 LT USB

Xi 410 LT ETH

Other Solar Applications

Crucial Role of Temperature Sensing in Accurate Solar Cell Flash Testing

Solar Cell Manufacturing: Thermal Quality Checks for Soldering & Tabbing

Steady State Thermography for Non-Intrusive Solar Module Defect Detection

Weak Shunt Identification in Solar Cells Production with Infrared Cameras

Talk to us about your IR Temperature Measurement Requirements

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