36 n MACHINE VISION April 2026 www.drivesncontrols.com High-speed camera monitors robot vibrations without needing sensors Japanese researchers have devised a non-contact system for monitoring the vibrations of industrial robots while they are working, without using costly physical sensors that could be subject to interference. The researchers, from Hiroshima University, are using highspeed cameras, and a non-contact optical technique called Digital Image Correlation (DIC), to measure surface deformation, displacement and strain in the robots. The technique could be used for predictive maintenance. Abnormal vibrations in industrial robots can signal mechanical issues such as imbalances, loose components, worn bearings, or structural weaknesses. These issues can lead to unexpected shutdowns, costing thousands of dollars per hour in lost production. Poor maintenance can also lead to unpredictable robot behaviour, creating hazards for workers. Sensor drawbacks Physical sensors such as piezoelectric accelerometers can be highly effective for monitoring vibrations in robots, but they have drawbacks – particularly their high costs and the fact that they add weight to moving robotic arms. Wired sensors also need cables that trail along the arms, potentially resulting in problems of flexing, wear, tangling or breakage. The Japanese researchers used a sixdegree-of-freedom vertical articulated robot as their measurement target. After applying a random, high-contrast speckle pattern to the robot, they attached a small vibration exciter. They captured video of the moving robot using a Mikrotron EoSens 2.0CXP2 camera with a 20mm focal-length lens, located 1.2m from the robot. The video was divided into individual frames based on a frame rate of 1,000 frames per second. Each 1920 × 1080 pixel frame was divided into 128 × 128-pixel blocks, yielding 435 sub-images that simulated the operation of vibration sensors. A vibration visualisation algorithm developed in C++ with Microsoft Visual Studio Community 2017 was optimised using an Nvidia GeForce RTX 2080 GPU. The algorithm tracked changes in the speckle pattern on the robot, generating detailed 2D maps of how the surface was moving as a result of vibrations. High accuracy The system captured simultaneous measurements across the robot, detecting both high- and low-frequency vibrations. It achieved a level of accuracy that the researchers say would have been difficult to achieve using sensor-based techniques. The scientists now plan to enhance the robustness and practical applicability of their technique. They want to extend it to perform real-time vibration monitoring while the robot is moving, enabling more accurate characterisation of its operational dynamics. Other robot configurations will also be tested, and the researchers may turn to multi-camera stereo imaging to enable full 3D vibration analysis. • In 2022, SVS-Vistek bought Mikrotron. In January 2026, Allied Vision, Chromasens, Mikrotron, Net and SVS-Vistek were all consolidated under Allied Vision, which is part of the machine vision division of the TKH Group. High-speed cameras could offer a non-contact alternative to costly, interference-prone sensors for measuring vibrations in robots, researchers in Japan are suggesting. Multi-point Digital Image Correlation measurements of the robot in three operating positions Photo: Hiroshima University
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