scholarly journals Orthogonality Measurement of Three-Axis Motion Trajectories for Micromanipulation Robot Systems

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 344
Author(s):  
Yuezong Wang ◽  
Jinghui Liu ◽  
Hao Chen ◽  
Jiqiang Chen ◽  
Yangyang Lu
Keyword(s):  
Coordinate System ◽  
Coordinate Frame ◽  
Reference Coordinate System ◽  
Vector Operation ◽  
Motion Trajectories ◽  
Displacement Sensors ◽  
Robot Systems ◽  
Trajectory Measurement ◽  
Assembly Error ◽  
Line Fitting

In robotic micromanipulation systems, the orthogonality of the three-axis motion trajectories of the motion control systems influences the accuracy of micromanipulation. A method of measuring and evaluating the orthogonality of three-axis motion trajectories is proposed in this paper. Firstly, a system for three-axis motion trajectory measurement is developed and an orthogonal reference coordinate system is designed. The influence of the assembly error of laser displacement sensors on the reference coordinate system is analyzed using simulation. An approach to estimating the orthogonality of three-axis motion trajectories and to compensating for its error is presented using spatial line fitting and vector operation. The simulation results show that when the assembly angle of the laser displacement sensors is limited within a range of 10°, the relative angle deviation of the coordinate axes of the reference coordinate frame is approximately 0.09%. The experiment results show that precision of spatial line fitting is approximately 0.02 mm and relative error of the orthogonality measurement is approximately 0.3%.

scholarly journals Reference Coordinate System Requirements for Space Physics and Astronomy

1980 ◽  
Vol 56 ◽  
pp. 71-75
Author(s):  
J. D. Mulholland
Keyword(s):  
Boundary Conditions ◽  
Coordinate System ◽  
Space Physics ◽  
Coordinate Frame ◽  
Coordinate Systems ◽  
Reference Coordinate System ◽  
System Requirements ◽  
Internal Coherence ◽  
Earth Dynamics

AbstractChanges in reference coordinate systems have major implications well beyond the realm of Earth dynamics. Definitions that serve geodynamic convenience may cause considerable effects for other disciplines. After presenting some typical areas in which coordinate frame definitions are important, recommendations are given for criteria to be considered as boundary conditions in discussing changes. These cover such qualities as observability, complexity, stability, internal coherence and uniqueness.

2.2. Working Group 2: Conceptual Definitions of Reference Coordinate Systems for Earth Dynamics

1975 ◽  
Vol 26 ◽  
pp. 21-26
Keyword(s):  
Coordinate System ◽  
Working Group ◽  
General Character ◽  
Coordinate Systems ◽  
Reference Coordinate System ◽  
Group 2 ◽  
Definition Of ◽  
Earth Dynamics

An ideal definition of a reference coordinate system should meet the following general requirements:1. It should be as conceptually simple as possible, so its philosophy is well understood by the users.2. It should imply as few physical assumptions as possible. Wherever they are necessary, such assumptions should be of a very general character and, in particular, they should not be dependent upon astronomical and geophysical detailed theories.3. It should suggest a materialization that is dynamically stable and is accessible to observations with the required accuracy.

scholarly journals LevioSAM: Fast lift-over of alternate reference alignments

2021 ◽  
Author(s):  
Taher Mun ◽  
Nae-Chyun Chen ◽  
Ben Langmead
Keyword(s):  
Population Genetics ◽  
Coordinate System ◽  
Data Structures ◽  
Succinct Data Structures ◽  
Reference Coordinate System ◽  
Link Type ◽  
A Chain ◽  
Time Required ◽  
Effective Use

AbstractMotivationAs more population genetics datasets and population-specific references become available, the task of translating (“lifting”) read alignments from one reference coordinate system to another is becoming more common. Existing tools generally require a chain file, whereas VCF files are the more common way to represent variation. Existing tools also do not make effective use of threads, creating a post-alignment bottleneck.ResultsLevioSAM is a tool for lifting SAM/BAM alignments from one reference to another using a VCF file containing population variants. LevioSAM uses succinct data structures and scales efficiently to many threads. When run downstream of a read aligner, levioSAM completes in less than 13% the time required by an aligner when both are run with 16 threads.Availabilityhttps://github.com/alshai/[email protected], [email protected]

Reference coordinate system in design of shoe lasts

2009 ◽  
Vol 1 (sup1) ◽  
pp. 8-10
Author(s):  
Kirill Zamarashkin ◽  
Nikolai Zamarashkin
Keyword(s):  
Coordinate System ◽  
Reference Coordinate System

scholarly journals Research on Visualization and Error Compensation of Demolition Robot Attachment Changing

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2428 ◽  
Author(s):  
Qian Deng ◽  
Shuliang Zou ◽  
Hongbin Chen ◽  
Weixiong Duan
Keyword(s):  
Coordinate System ◽  
Coordinate Transformation ◽  
Error Compensation ◽  
Compensation Method ◽  
Positioning Error ◽  
Nuclear Facility ◽  
Reference Coordinate System ◽  
Accuracy Requirement ◽  
Docking Accuracy ◽  
Changing Process

Attachment changing in demolition robots has a high docking accuracy requirement, so it is hard for operators to control this process remotely through the perspective of a camera. To solve this problem, this study investigated positioning error and proposed a method of error compensation to achieve a highly precise attachment changing process. This study established a link parameter model for the demolition robot, measured the error in the attachment changing, introduced a reference coordinate system to solve the coordinate transformation from the dock spot of the robot’s quick-hitch equipment to the dock spot of the attachment, and realized error compensation. Through calculation and experimentation, it was shown that the error compensation method proposed in this study reduced the level of error in attachment changing from the centimeter to millimeter scale, thereby meeting the accuracy requirements for attachment changing. This method can be applied to the remote-controlled attachment changing process of demolition robots, which provides the basis for the subsequent automatic changing of attachments. This has the potential to be applied in nuclear facility decommissioning and dismantling, as well as other radioactive environments.

A New Three-Dimensional Moving Timoshenko Beam Element for Moving Load Problem Analysis

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Yan Xu ◽  
Weidong Zhu ◽  
Wei Fan ◽  
Caijing Yang ◽  
Weihua Zhang
Keyword(s):  
Dynamic Analysis ◽  
Coordinate System ◽  
Timoshenko Beam ◽  
Moving Load ◽  
Three Dimensional ◽  
Beam Element ◽  
Superposition Method ◽  
Reference Coordinate System ◽  
Current Formulation ◽  
Timoshenko Beam Element

Abstract A new three-dimensional moving Timoshenko beam element is developed for dynamic analysis of a moving load problem with a very long beam structure. The beam has small deformations and rotations, and bending, shear, and torsional deformations of the beam are considered. Since the dynamic responses of the beam are concentrated on a small region around the moving load and most of the long beam is at rest, owing to the damping effect, the beam is truncated with a finite length. A control volume that is attached to the moving load is introduced, which encloses the truncated beam, and a reference coordinate system is established on the left end of the truncated beam. The arbitrary Lagrangian–Euler method is used to describe the relationship of the position of a particle on the beam between the reference coordinate system and the global coordinate system. The truncated beam is spatially discretized using the current beam elements. Governing equations of a moving element are derived using Lagrange’s equations. While the whole beam needs to be discretized in the finite element method or modeled in the modal superposition method (MSM), only the truncated beam is discretized in the current formulation, which greatly reduces degrees-of-freedom and increases the efficiency. Furthermore, the efficiency of the present beam element is independent of the moving load speed, and the critical or supercritical speed range of the moving load can be analyzed through the present method. After the validation of the current formulation, a dynamic analysis of three-dimensional train–track interaction with a non-ballasted track is conducted. Results are in excellent agreement with those from the commercial software simpack where the MSM is used, and the calculation time of the current formulation is one-third of that of simpack. The current beam element is accurate and more efficient than the MSM for moving load problems of long three-dimensional beams. The derivation of the current beam element is straightforward, and the beam element can be easily extended for various other moving load problems.

A Symmetrical Coordinate Frame on the Hexagonal Grid for Computer Graphics and Vision

1993 ◽  
Vol 115 (3) ◽  
pp. 447-449 ◽  
Author(s):  
I. Her
Keyword(s):  
Computer Vision ◽  
Computer Graphics ◽  
Coordinate System ◽  
Distance Functions ◽  
Coordinate Frame ◽  
Vision Systems ◽  
Hexagonal Grid ◽  
Spatial Properties ◽  
Computer Vision Systems

This paper investigates the hexagonal tessellation of picture elements used in computer graphics and computer vision systems. Its purpose is to propose a symmetrical hexagonal coordinate frame to replace the existing oblique coordinate system. In the proposed symmetrical coordinate frame, spatial properties of the hexagonal grid such as distance functions are better represented.

scholarly journals Large-Scale Light Field Capture and Reconstruction

2020 ◽  
Author(s):  
Yuan Gao
Keyword(s):  
Coordinate System ◽  
Real World ◽  
Large Scale ◽  
Light Field ◽  
Geometric Constraints ◽  
Video Frame ◽  
Coordinate Frame ◽  
Light Fields ◽  
Synthesis Methods ◽  
Kinect V2

This thesis discusses approaches and techniques to convert Sparsely- Sampled Light Fields (SSLFs) into Densely-Sampled Light Fields (DSLFs), which can be used for visualization on 3DTV and Virtual Reality (VR) de- vices. Exemplarily, a movable 1D large-scale light field acquisition system for capturing SSLFs in real-world environments is evaluated. This system consists of 24 sparsely placed RGB cameras and two Kinect V2 sensors. The real-world SSLF data captured with this setup can be leveraged to reconstruct real-world DSLFs. To this end, three challenging problems require to be solved for this system: (i) how to estimate the rigid trans- formation from the coordinate system of a Kinect V2 to the coordinate system of an RGB camera; (ii) how to register the two Kinect V2 sensors with a large displacement; (iii) how to reconstruct a DSLF from a SSLF with moderate and large disparity ranges. To overcome these three challenges, we propose: (i) a novel self- calibration method, which takes advantage of the geometric constraints from the scene and the cameras, for estimating the rigid transformations from the camera coordinate frame of one Kinect V2 to the camera coordi- nate frames of 12-nearest RGB cameras; (ii) a novel coarse-to-fine approach for recovering the rigid transformation from the coordinate system of one Kinect to the coordinate system of the other by means of local color and geometry information; (iii) several novel algorithms that can be categorized into two groups for reconstructing a DSLF from an input SSLF, including novel view synthesis methods, which are inspired by the state-of-the-art video frame interpolation algorithms, and Epipolar-Plane Image (EPI) in- painting methods, which are inspired by the Shearlet Transform (ST)-based DSLF reconstruction approaches.

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