Research on Measurement Accuracy of Laser Tracking System Based on Spherical Mirror with Rotation Errors of Gimbal Mount Axes

Shi, Zhaoyao; Song, Huixu; Chen, Hongfang; Sun, Yanqiang

doi:10.1515/msr-2018-0003

Cited by 5 publications

(4 citation statements)

References 14 publications

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“…Instead of placing sensors directly on the orientation platform, mirrors can be placed there to only adjust the optical path of the sensors [74,75]. While this lowers required payload capacities and may allow for a larger range of motion, it introduces difficulties in controlling the system and promotes errors through sensor and axis misalignment [76] which need to be compensated for. Additionally, some sensor modalities, such as certain laser based devices, do not work using a mirror.…”

Section: Pointing Mechanismsmentioning

confidence: 99%

High-Precision Low-Cost Gimballing Platform for Long-Range Railway Obstacle Detection

Assaf

Cornelius

Cadena

et al. 2022

Sensors

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Increasing demand for rail transportation results transportation by rail, resulting in denser and more high-speed usage of the existing railway network, making makes new and more advanced vehicle safety systems necessary. Furthermore, high traveling speeds and the greatlarge weights of trains lead to long braking distances—all of which necessitates Long braking distances, due to high travelling speeds and the massive weight of trains, necessitate a Long-Range Obstacle Detection (LROD) system, capable of detecting humans and other objects more than 1000 m in advance. According to current research, only a few sensor modalities are capable of reaching this far and recording sufficiently accurate enoughdata to distinguish individual objects. The limitation of these sensors, such as a 1D-Light Detection and Ranging (LiDAR), is however a very narrow Field of View (FoV), making it necessary to use ahigh-precision means of orienting to target them at possible areas of interest. To close this research gap, this paper presents a novel approach to detecting railway obstacles by developinga high-precision pointing mechanism, for the use in a future novel railway obstacle detection system In this work such a high-precision pointing mechanism is developed, capable of targeting aiming a 1D-LiDAR at humans or objects at the required distance. This approach addresses To address the challenges of a low target pricelimited budget, restricted access to high-precision machinery and equipment as well as unique requirements of our target application., a novel pointing mechanism has been designed and developed. By combining established elements from 3D printers and Computer Numerical Control (CNC) machines with a double-hinged lever system, simple and cheaplow-cost components are capable of precisely orienting an arbitrary sensor platform. The system’s actual pointing accuracy has been evaluated using a controlled, in-door, long-range experiment. The device was able to demonstrate a precision of 6.179 mdeg, which is at the limit of the measurable precision of the designed experiment.

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Section: Pointing Mechanismsmentioning

confidence: 99%

High-Precision Low-Cost Gimballing Platform for Long-Range Railway Obstacle Detection

Assaf

Cornelius

Cadena

et al. 2022

Sensors

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“…The schematic diagram of the laser tracer is shown in Fig. 1 [12]. In order to clearly identify the characteristics of all the geometrical errors, the geometrical errors are divided into two categories according to the principle of generation -originally geometrical errors and derivatively geometrical errors.…”

Section: Geometrical Error Sources Of Rotatory Axes In Laser Tracermentioning

confidence: 99%

“…Point b0, b1 and direction vector nB0 are given as (10) - (12): (11) cos 0 sin (12) Point b0(θ, φ), b1(θ, φ) and direction vector nB(θ, φ) has changed after rotation, and are given as (13) -(15):…”

Section: B a A D D E E F F G B H P P P P P P P P P Pmentioning

confidence: 99%

A Simple Integrated Geometrical Error Model for Laser Tracer

2018

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Geometrical errors of 2D gimbal mount axes are studied for laser tracer for the sake of realizing rapid detection for numerical control equipment. The high precision reference sphere, which serves as the reflection unit and is set on the base, avoids the influence on measurement accuracy caused by the movements of rotatory axes, and ensures that laser tracer owns large tracing angle. The nonlinear coupling relationship between the geometrical errors and the measurement accuracy of laser tracer is analyzed; the integrated geometrical error model of 2D gimbal mount axes and laser interferometry system is established; the error map of the measuring system is brought. The simulation results demonstrate that the measurement error of the laser tracer is certain and unique after the value and direction of all the geometrical errors determined.

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“…In the ground simulation experiment, the quality of the measurement results depend on the choice of measurement conditions. The selection of new measurement conditions parameters, determination of parameter optimization criteria [ 19 , 20 , 21 ] and optimization algorithms [ 22 , 23 , 24 , 25 , 26 ] will determine the final accuracy and practicability of the ground simulation experiment.…”

Section: Introductionmentioning

confidence: 99%

Least-Square-Method-Based Optimal Laser Spots Acquisition and Position in Cooperative Target Measurement

Feng

et al. 2022

Sensors

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The relative positioning precisions of coordinate points is an important indicator that affects the final accuracy in the visual measurement system of space cooperative targets. Many factors, such as measurement methods, environmental conditions, data processing principles and equipment parameters, are supposed to influence the cooperative target’s acquisition and determine the precision of the cooperative target’s position in a ground simulation experiment with laser projected spots on parallel screens. To overcome the precision insufficiencies of cooperative target measurement, the factors of the laser diode supply current and charge couple device (CCD) camera exposure time are studied in this article. On the hypothesis of the optimal experimental conditions, the state equations under the image coordinates’ system that describe the laser spot position’s variation are established. The novel optimizing method is proposed by taking laser spot position as state variables, diode supply current and exposure time as controllable variables, calculating the optimal controllable variables through intersecting the focal spot centroid line and the 3-D surface, and avoiding the inconvenience of solving nonlinear equations. The experiment based on the new algorithm shows that the optimal solution can guarantee the focal spot’s variation range in 5–10 pixels under image coordinates’ system equivalent to the space with a 3 m distance and 0.6–1.2 mm positioning accuracy.

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Research on Measurement Accuracy of Laser Tracking System Based on Spherical Mirror with Rotation Errors of Gimbal Mount Axes

Cited by 5 publications

References 14 publications

High-Precision Low-Cost Gimballing Platform for Long-Range Railway Obstacle Detection

High-Precision Low-Cost Gimballing Platform for Long-Range Railway Obstacle Detection

A Simple Integrated Geometrical Error Model for Laser Tracer

Least-Square-Method-Based Optimal Laser Spots Acquisition and Position in Cooperative Target Measurement

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