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The accuracy of laser trackers in large-scale dimensional metrology is subject to various influencing factors, with instrument positioning being a primary source of error. To address this, a multi-objective optimization algorithm, grounded in the Pareto improvement principle, is proposed. This algorithm is designed to optimize instrument placement, thereby minimizing measurement errors and enhancing the algorithm's efficacy in error reduction. Thereby, this article proved that positioning the laser tracker consistently on one side of the measurement area and aligning its height with the measuring points can effectively reduce the uncertainty of control point errors by up to 50%.
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http://dx.doi.org/10.1063/5.0207241 | DOI Listing |
Opt Express
June 2025
For ground-based segmented telescopes, the active control system primarily adjusts three out-of-plane DOFs: tip, tilt, and piston. In contrast, in-plane DOFs rely on high-precision mechanical alignment. A systematic analysis of the effects of in-plane motion on the optical performance of ring segmented mirror systems is presented, and an analytical relationship between in-plane motion and the higher-order residual aberrations after tilt compensation is derived.
View Article and Find Full Text PDFSci Data
July 2025
Division of Biomechanics and Research Development, Department of Biomechanics, and Center for Research in Human Movement Variability, University of Nebraska at Omaha, Omaha, NE 68182, USA.
We present a publicly available dataset, offering annotated full-body kinematics, gaze tracking, and ground reaction forces and moments from 48 healthy young adults performing a life-size suprapostural task. Using a 12-camera motion capture system, eye tracker, and force plate, we recorded full-body kinematics, eye gaze and pupil diameter, and ground reaction forces and moments as participants completed four tasks: standing upright, performing the Trail Making Test (TMT) Part A projected on a screen using a laser pointer and repeating these conditions on a wobble board inducing instability along the mediolateral axis. Each trial lasted five minutes, and the total number of trail connections was recorded.
View Article and Find Full Text PDFPhys Imaging Radiat Oncol
July 2025
Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland.
In-room computer tomography (CT) on-rails scanners are available in proton therapy centers but often limited to control imaging, due to geometric distortion and lack of integration. We present a calibration method combining CT-on-rails with a robotic table to achieve sub-millimeter patient positioning accuracy. Geometric distortions in 3DCT and topogram images were corrected using affine models and validated with laser tracker data.
View Article and Find Full Text PDFBiomimetics (Basel)
June 2025
College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
This study presents an integrated stiffness modeling and evaluation framework for an orthopedic surgical robot, aiming to enhance cutting accuracy and operational stability. A comprehensive stiffness model is developed, incorporating the stiffness of the end-effector, cutting tool, and force sensor. End-effector stiffness is computed using the virtual joint method based on the Jacobian matrix, enabling accurate analysis of stiffness distribution within the robot's workspace.
View Article and Find Full Text PDFSensors (Basel)
March 2025
Microsystems and Nanotechnology Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
We describe a method to calibrate angular positioning errors of a rotation stage using a laser tracker (LT), a plane mirror mounted on the stage, and stationary registration nests placed around the stage. Our technique involves determining the direction of the normal vector to the plane of the mirror at each angular step by performing two LT measurements-one directly to a stationary spherically mounted retroreflector (SMR), and another to the same SMR by bouncing the laser off a mirror mounted on the rotation stage. Because the angular range that can be measured from a single LT station is limited by the angle of incidence on the mirror, multiple LT stations are necessary to cover the full 360°, hence the need for stationary registration nests to tie the LT data into a common coordinate frame.
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