scholarly journals Ultraprecision Real-Time Displacements Calculation Algorithm for the Grating Interferometer System

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2409 ◽  
Author(s):  
Weinan Ye ◽  
Ming Zhang ◽  
Yu Zhu ◽  
Leijie Wang ◽  
Jinchun Hu ◽  
...  
Keyword(s):  
Real Time ◽  
Affine Transformation ◽  
Degrees Of Freedom ◽  
Diffraction Spot ◽  
Calculation Algorithm ◽  
Six Degrees Of Freedom ◽  
Time Calculation ◽  
Interference Signals ◽  
Grating Interferometer ◽  
Optical Paths

Grating interferometry is an environmentally stable displacement measurement technique that has significant potential for identifying the position of the wafer stage. A fast and precise algorithm is required for real-time calculation of six degrees-of-freedom (DOF) displacement using phase shifts of interference signals. Based on affine transformation, we analyze diffraction spot displacement and changes in the internal and external effective optical paths of the grating interferometer caused by the displacement of the wafer stage (DOWS); then, we establish a phase shift-DOWS model. To solve the DOWS in real time, we present a polynomial approximation algorithm that uses the frequency domain characteristics of nonlinearities to achieve model reduction. The presented algorithm is verified by experiment and ZEMAX simulation.

Comparisons of Turning Abilities of Submarine With Different Rudder Configurations

2018 ◽  
Author(s):  
Dakui Feng ◽  
Xuanshu Chen ◽  
Hao Liu ◽  
Zhiguo Zhang ◽  
Xianzhou Wang
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Control Device ◽  
Body Motion ◽  
The Real ◽  
Six Degrees Of Freedom ◽  
Overlapping Grids ◽  
Free Running ◽  
Turning Radius ◽  
Time Changes

Submarine is usually equipped with two different control device arrangements, namely a cruciform and a X rudder configuration. In this paper, numerical simulations of the DARPA Suboff submarine and its retrofitted submarine with a X rudder configuration are presented. Turning simulations in model scale were studied to compare the turning abilities of the two different control device arrangements. The computations were performed with a house viscous CFD solver based on the conservative finite difference method. In the solver, RANS equation are solved coupled with six degrees of freedom (6DOF) solid body motion equations of the submarine in real time. The structured dynamic overlapping grids were used to simulate the real-time changes of the attitude of the submarine and the rotation of the rudder. The volume force method was used to replace the real propeller to realize the self-propelled movement of submarine. In the free running maneuvering simulations, the submarines move at the same initial velocity and rudder angle, restricted to the horizontal plane with four degrees of freedom (4DOF). Comparisons of the trajectory and kinematic parameters including relative turning radius and turning period between the two cases were presented in this paper. The results show that, compared with the cruciform rudder configuration, the X rudder configuration has obvious advantages for submarine in the turning abilities.

scholarly journals Testing of a MEMS Dynamic Inclinometer Using the Stewart Platform

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4233 ◽  
Author(s):  
Zhihua Liu ◽  
Chenguang Cai ◽  
Ming Yang ◽  
Ying Zhang
Keyword(s):  
Mechanical System ◽  
Real Time ◽  
Degrees Of Freedom ◽  
Cross Coupling ◽  
Micro Electro Mechanical System ◽  
Stewart Platform ◽  
Forward Kinematics ◽  
Six Degrees Of Freedom ◽  
Position And Orientation ◽  
The Cross

The micro-electro-mechanical system (MEMS) dynamic inclinometer integrates a tri-axis gyroscope and a tri-axis accelerometer for real-time tilt measurement. The Stewart platform has the ability to generate six degrees of freedom of spatial orbits. The method of applying spatial orbits to the testing of MEMS inclinometers is investigated. Inverse and forward kinematics are analyzed for controlling and measuring the position and orientation of the Stewart platform. The Stewart platform is controlled to generate a conical motion, based on which the sensitivities of the gyroscope, accelerometer, and tilt sensing are determined. Spatial positional orbits are also generated in order to obtain the tilt angles caused by the cross-coupling influence. The experiment is conducted to show that the tested amplitude frequency deviations of the gyroscope and tilt sensing sensitivities between the Stewart platform and the traditional rotator are less than 0.2 dB and 0.1 dB, respectively.

Performance of Developed Driving Simulator With Full Vehicle Model of Multibody Dynamics

2001 ◽  
Author(s):  
Taichi Shiiba ◽  
Yoshihiro Suda
Keyword(s):  
Real Time ◽  
Multibody Dynamics ◽  
Degrees Of Freedom ◽  
Driving Simulator ◽  
Vehicle Model ◽  
Full Vehicle ◽  
Real Time Analysis ◽  
Motion System ◽  
Time Calculation ◽  
6 Degrees Of Freedom

Abstract In this paper, the authors propose to apply the full vehicle model of multibody dynamics to driving simulator with 6 degrees of freedom motion system. By this proposal, the characteristics of driving simulator become very similar to the actual automobiles. It becomes possible to predict the performance of vehicle dynamics and the riding comfort by feeling test without prototyping automobile. To realize real-time calculation that is necessary for driving simulator, the authors proposed approximated real-time analysis method. By this method, real-time vehicle analysis of 2 ms step time of numerical integration is achieved with 91 degrees of freedom vehicle model.

scholarly journals Real-Time Estimation for Roll Angle of Spinning Projectile Based on Phase-Locked Loop on Signals from Single-Axis Magnetometer

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 839 ◽  
Author(s):  
Zhaowei Deng ◽  
Qiang Shen ◽  
Zilong Deng ◽  
Jisi Cheng
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Phase Error ◽  
Time Estimation ◽  
Phase Locked Loop ◽  
Roll Angle ◽  
Six Degrees Of Freedom ◽  
Blind Area ◽  
Real Time Estimation ◽  
Spinning Projectile

As roll angle measurement is essential for two-dimensional course correction fuze (2-D CCF) technology, a real-time estimation of roll angle of spinning projectile by single-axis magnetometer is studied. Based on the measurement model, a second-order frequency-locked loop (FLL)-assisted third-order phase-locked loop (PLL) is designed to obtain rolling information from magnetic signals, which is less dependent on the amplitude and able to reduce effect from geomagnetic blind area. Method of parameters optimization of tracking loop is discussed in the circumstance of different speed and it is verified by six degrees of freedom (six degrees of freedom (DoF)) trajectory. Also, the measurement error is analyzed to improve the accuracy of designed system. At last, experiments on rotary table are carried out to validate the proposed method indicating the designed system is able to track both phase and speed accurately and stably. The standard deviation (SD) of phase error is no more than 3°.

Real-time contactless measurement of robot pose in six degrees of freedom

Measurement ◽  
1995 ◽  
Vol 14 (3-4) ◽  
pp. 255-264 ◽  
Author(s):  
Johann P. Prenninger ◽  
Karl M. Filz ◽  
Markus Vincze ◽  
Helmut Gander
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Contactless Measurement ◽  
Six Degrees Of Freedom

Research and Design of Distributed Controllers for Mechanical Arms of Humanoid Robot Based on FCS

2013 ◽  
Vol 419 ◽  
pp. 682-687
Author(s):  
Chong Ran Jiang ◽  
Li Li ◽  
Jin Quan Bai ◽  
Yan Zhong Huo
Keyword(s):  
Real Time ◽  
Study Design ◽  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Robot System ◽  
Six Degrees Of Freedom ◽  
Distributed Controllers ◽  
Research And Design

According to the high real-time and the high anti-interference which required by the machanical arms of humanoid robot, a distributed controllers for mechanical arms of humanoid robot system based on CAN is developed, to which C8051F041 micro controller is applied as the joint controllers. The circuits of incremental discs and speed detection as well as their applications are designed. The achievement of develop and design on distributed controllers for six degrees of freedom mechanical arms fulfills the trajectory requirement of humanoid robot qualification and the system according to the study design.

Water Immersion Reduced-Gravity Simulation

1969 ◽  
Vol 11 (5) ◽  
pp. 473-487 ◽  
Author(s):  
Otto F. Trout ◽  
William J. Bruchey
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Water Immersion ◽  
Training System ◽  
Test Procedures ◽  
Six Degrees Of Freedom ◽  
Engineering Data ◽  
Immersion Technique ◽  
Partial Gravity ◽  
Rescue Procedures

A water immersion technique for simulating zero- and partial-gravity conditions has been developed and employed to examine several extravehicular task areas in space. The technique allows the pressure-suited subject to move in six degrees of freedom unencumbered by connecting supports and simulates his biomechanical performance in weightless space. The technique is useful in examining the astronaut's capability to execute extravehicular work procedures, developing man-system engineering data, and as a training system. Several extravehicular task areas have been examined, including ingress-egress through airlock systems, manual self-locomotion, manipulation and maintenance tasks, and assessment of rescue procedures. Although limited in the study of rapid translatory tasks by the drag and damping effects of the water, the technique permits a perceptual equivalent simulation of complex manipulative tasks in real time. A description of the test procedures, equipment, and several typical tests is provided.

Real-Time Variance Calculation Method for Synchronous System Clock Based on Adaptive Exponential Smoothing

2014 ◽  
Vol 513-517 ◽  
pp. 1555-1560
Author(s):  
Yan Xu ◽  
Zhi Qiang Wang ◽  
Qing Yang
Keyword(s):  
Real Time ◽  
Environmental Changes ◽  
Exponential Smoothing ◽  
Calculation Algorithm ◽  
The Real ◽  
Synchronous System ◽  
System Clock ◽  
Time Calculation ◽  
Short Time ◽  
Variance Calculation

An adaptive clock variance calculation algorithm is designed to improve the real-time characteristics and complexity of general method. This algorithm use the latency and smoothing characteristics of exponential smoothing to achieve real-time calculation online. Using this algorithm, synchronous system can response to environmental changes in a short time. The test result shows that the real-time characteristics and output robustness can be improved obviously.

scholarly journals RECREATING CULTURAL HERITAGE ENVIRONMENTS FOR VR USING PHOTOGRAMMETRY

2019 ◽  
Vol XLII-2/W9 ◽  
pp. 305-310 ◽  
Author(s):  
A. Dhanda ◽  
M. Reina Ortiz ◽  
A. Weigert ◽  
A. Paladini ◽  
A. Min ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Cultural Heritage ◽  
Real Time ◽  
Structure From Motion ◽  
Degrees Of Freedom ◽  
Six Degrees Of Freedom ◽  
Whole Space ◽  
Optimized Model ◽  
Normal Maps

<p><strong>Abstract.</strong> In this paper, we propose a workflow for recreating places of cultural heritage in Virtual Reality (VR) using structure from motion (SfM) photogrammetry. The unique texture of heritage places makes them ideal for full photogrammetric capture. An optimized model is created from the photogrammetric data so that it is small enough to render in a real-time environment. The optimized model, combined with mesh maps (texture maps, normal maps, etc.) looks like the original high detail model. The capture of a whole space makes it possible to create a VR experience with six degrees of freedom (6DoF) that allows the user to explore the historic place. Creating these experiences can bring people to cultural heritage that is either endangered or too remote for some people to access. The workflow described in this paper will be demonstrated with the case study of Myin-pya-gu, an 11th century temple in Bagan, Myanmar.</p>

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