Manufacturers need online methods that give up-to-date information of system capabilities to know and predict the performance of their machine tools. Use of an inertial measurement unit (IMU) is attractive for on-machine condition monitoring, so methods based on spatial filters were developed to determine rail wear conditions of linear guideways of a carriage from its IMU-based error motion. Rail wear-induced changes in translational and angular error motions as small as 1.5 μm and 3.0 microradians, respectively, could be resolved. A corresponding two-part root-cause analysis procedure was developed to determine the rail locations of error motion degradation as well as the most probable physical location of damage that causes the detected error motion changes. Another analysis method determined the root cause of non-localized damage along each rail. These approaches support the development of smart machine tools that provide actionable intelligence to manufacturers for early warnings of system degradation.
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http://dx.doi.org/10.1016/j.ijmachtools.2019.05.004 | DOI Listing |
Infant Behav Dev
January 2025
Universität zu Köln, Richard Strauss Straße 2, Cologne 50931, Germany.
The study examined the saccadic behavior of 4- to 10-month-old infants when tracking a two-dimensional linear motion of a circle that occasionally bounced off a barrier constituted by the screen edges. It was investigated whether infants could anticipate the angle of the circle's direction after the bounce and the circle's displacement from the location of bounce. Seven bounce types were presented which differed in the angle of incidence.
View Article and Find Full Text PDFSci Rep
January 2025
Zhongyuan University of Technology, Zhengzhou, 450007, China.
This paper studies the practical prescribed-time control problem for dual-arm robots handling an object with output constraints. Firstly, by utilizing the property that the sum of internal forces in the grasping space is zero, the system model is obtained and decomposed into the contact force model and free motion model, which are orthogonal to each other. Furthermore, by combining the performance function and constraint function, the original system tracking error is transformed to a new one, whose boundedness can ensure that the original system variable converges to the predetermined range within the specified time.
View Article and Find Full Text PDFMagn Reson Imaging
January 2025
Department of Medical Imaging, Pingyin people's Hospital, Jinan 250400, China.
Magnetic Resonance Imaging is a cornerstone of medical diagnostics, providing high-quality soft tissue contrast through non-invasive methods. However, MRI technology faces critical limitations in imaging speed and resolution. Prolonged scan times not only increase patient discomfort but also contribute to motion artifacts, further compromising image quality.
View Article and Find Full Text PDFJ Biomech
January 2025
Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital, Sichuan University Chengdu Sichuan Province China. Electronic address:
OpenCap, a smartphone-based markerless system, offers a cost-effective alternative to traditional marker-based systems for gait analysis. However, its kinematic measurement accuracy must be evaluated before widespread use in clinical practice. This study aimed to evaluate OpenCap for lower-limb joint angle measurements during walking in patients with knee osteoarthritis (OA) and to compare error metrics between patients and healthy controls.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Department of Electrical and Information Engineering, Kiel University, 24143 Kiel, Germany.
Clinical motion analysis plays an important role in the diagnosis and treatment of mobility-limiting diseases. Within this assessment, relative (point-to-point) tracking of extremities could benefit from increased accuracy. Given the limitations of current wearable sensor technology, supplementary spatial data such as distance estimates could provide added value.
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