Microelectromechanical Hybrid Gyroscope Design of Closed-Loop Detection Circuit Based on FPGA

2013 ◽  
Vol 562-565 ◽  
pp. 172-177
Author(s):  
Dun Zhu Xia ◽  
Cheng Yu ◽  
Shou Rong Wang ◽  
Hong Sheng Li
Keyword(s):  
Closed Loop ◽  
Rotation Frequency ◽  
Digital Design ◽  
Closed Loops ◽  
Noise Interference ◽  
Scale Factors ◽  
Detection Circuit ◽  
Loop Detection ◽  
Sinusoidal Functions ◽  
Cross Axis

This paper presents a new microelectromechanical hybrid gyroscope (MHG) with three equilibrium rings. This structure can eliminate the error caused by the double rotation frequency of the driving shaft successfully. The MHG kinematic equations with three equilibrium rings are derived in this paper. Meanwhile, a new digital design and simulation of the MHG closed-loop detection circuit are proposed based on FPGA. The noise interference is weakened by using differential mode signal detection and the resources of FPGA are decreased by the loop diode demodulation in this paper. The cross axis coupling of the decoupled system is about 2.4%. The phase margin is 70deg and the magnitude margin is 22db after correction. The transcient response simulation is tested when the inputs are sinusoidal functions. The bandwidth and scale factors of x-axis and y-axis closed loops are analyzed in the paper. The bandwidth can reach about 70Hz and the scale factors of x-axis and y-axis closed loops are 0.1467V/o/s and -0.1467V/o/s respectively.

Triplet loss based metric learning for closed loop detection in VSLAM system

2021 ◽  
pp. 115646
Author(s):  
Jianfang Chang ◽  
Na Dong ◽  
Donghui Li ◽  
Minghui Qin
Keyword(s):  
Closed Loop ◽  
Metric Learning ◽  
Loop Detection ◽  
Triplet Loss

scholarly journals Fast and stable photoacoustic gas spectroscopy by frequency tracking of a quartz tuning fork in closed loop detection

2020 ◽  
Author(s):  
Maxime Duquesnoy ◽  
Raphaël Lévy ◽  
Jean-Michel Melkonian ◽  
Guillaume Aoust ◽  
Myriam Raybaut ◽  
...  
Keyword(s):  
Closed Loop ◽  
Tuning Fork ◽  
Quartz Tuning Fork ◽  
Frequency Tracking ◽  
Loop Detection

THE GEOMETRIC PHASE AND THE SCHWINGER TERM IN SOME MODELS

1992 ◽  
Vol 07 (21) ◽  
pp. 5045-5083 ◽  
Author(s):  
H. GROSSE ◽  
E. LANGMANN
Keyword(s):  
Parameter Space ◽  
Geometric Phase ◽  
Closed Loop ◽  
Parallel Transport ◽  
Quantum Mechanical System ◽  
Second Quantization ◽  
Closed Loops ◽  
Gauge Transformations ◽  
Canonical Anticommutation Relations ◽  
Inequivalent Representations

We discuss the quantization of fermions interacting with external fields and observe the occurrence of equivalent as well as inequivalent representations of the canonical anticommutation relations. Implementability of gauge and axial gauge transformations leads to generators which fulfil an algebra of current with a Schwinger term. This term can be written as a cocycle and leads to the boson-fermion correspondence. Transport of a quantum-mechanical system along a closed loop of parameter space may yield a geometric phase. We discuss models for which nonintegrable phase factors are obtained from the adiabatic parallel transport. After second quantization, one obtains, in addition, a Schwinger term. Depending on the type of transformation, a subtle relationship between these two obstructions can occur. We indicate finally how we may transport density matrices along closed loops in parameter space.

scholarly journals Flowering Buds of Globular Proteins: Transpiring Simplicity of Protein Organization

2002 ◽  
Vol 3 (6) ◽  
pp. 525-534 ◽  
Author(s):  
Igor N. Berezovsky ◽  
Edward N. Trifonov
Keyword(s):  
Protein Evolution ◽  
Closed Loop ◽  
Globular Proteins ◽  
Polymer Physics ◽  
Basic Unit ◽  
Amino Acid Residues ◽  
Sequence Motifs ◽  
Closed Loops ◽  
Physical Necessity ◽  
Functional Complexity

Structural and functional complexity of proteins is dramatically reduced to a simple linear picture when the laws of polymer physics are considered. A basic unit of the protein structure is a nearly standard closed loop of 25–35 amino acid residues, and every globular protein is built of consecutively connected closed loops. The physical necessity of the closed loops had been apparently imposed on the early stages of protein evolution. Indeed, the most frequent prototype sequence motifs in prokaryotic proteins have the same sequence size, and their high match representatives are found as closed loops in crystallized proteins. Thus, the linear organization of the closed loop elements is a quintessence of protein evolution, structure and folding.

Constraint Wrench Formulation for Closed-Loop Systems Using Two-Level Recursions

2007 ◽  
Vol 129 (12) ◽  
pp. 1234-1242 ◽  
Author(s):  
Himanshu Chaudhary ◽  
Subir Kumar Saha
Keyword(s):  
Lagrange Multipliers ◽  
Spanning Tree ◽  
Closed Loop ◽  
Equations Of Motion ◽  
Constraint Forces ◽  
Minimal Set ◽  
Closed Loops ◽  
Closed Loop Systems ◽  
Subsystem Level ◽  
Body Level

In order to compute the constraint moments and forces, together referred here as wrenches, in closed-loop mechanical systems, it is necessary to formulate a dynamics problem in a suitable manner so that the wrenches can be computed efficiently. A new constraint wrench formulation for closed-loop systems is presented in this paper using two-level recursions, namely, subsystem level and body level. A subsystem is referred here as the serial- or tree-type branches of a spanning tree obtained by cutting the appropriate joints of the closed loops of the system at hand. For each subsystem, unconstrained Newton–Euler equations of motion are systematically reduced to a minimal set in terms of the Lagrange multipliers representing the constraint wrenches at the cut joints and the driving torques/forces provided by the actuators. The set of unknown Lagrange multipliers and the driving torques/forces associated to all subsystems are solved in a recursive fashion using the concepts of a determinate subsystem. Next, the constraint forces and moments at the uncut joints of each subsystem are calculated recursively from one body to another. Effectiveness of the proposed algorithm is illustrated using a multiloop planar carpet scraping machine and the spatial RSSR (where R and S stand for revolute and spherical, respectively) mechanism.

Efficient Parallel Computer Simulation of the Motion Behaviors of Closed-Loop Multibody Systems

2007 ◽  
Author(s):  
Shanzhong Duan ◽  
Andrew Ries
Keyword(s):  
Parallel Computing ◽  
Multibody Systems ◽  
Closed Loop ◽  
High Efficiency ◽  
Equations Of Motion ◽  
Parallel Computer ◽  
Constraint Forces ◽  
Computing Systems ◽  
Closed Loops

This paper presents an efficient parallelizable algorithm for the computer-aided simulation and numerical analysis of motion behaviors of multibody systems with closed-loops. The method is based on cutting certain user-defined system interbody joints so that a system of independent multibody subchains is formed. These subchains interact with one another through associated unknown constraint forces fc at the cut joints. The increased parallelism is obtainable through cutting joints and the explicit determination of associated constraint forces combined with a sequential O(n) method. Consequently, the sequential O(n) procedure is carried out within each subchain to form and solve the equations of motion while parallel strategies are performed between the subchains to form and solve constraint equations concurrently. For multibody systems with closed-loops, joint separations play both a role of creation of parallelism for computing load distribution and a role of opening a closed-loop for use of the O(n) algorithm. Joint separation strategies provide the flexibility for use of the algorithm so that it can easily accommodate the available number of processors while maintaining high efficiency. The algorithm gives the best performance for the application scenarios for n>>1 and n>>m, where n and m are number of degree of freedom and number of constraints of a multibody system with closed-loops respectively. The algorithm can be applied to both distributed-memory parallel computing systems and shared-memory parallel computing systems.

scholarly journals Incremental Pose Map Optimization for Monocular Vision SLAM Based on Similarity Transformation

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4945 ◽  
Author(s):  
Wenlei Liu ◽  
Sentang Wu ◽  
Zhongbo Wu ◽  
Xiaolong Wu
Keyword(s):  
Global Optimization ◽  
Closed Loop ◽  
Similarity Transformation ◽  
Direct Method ◽  
Depth Estimation ◽  
Monocular Vision ◽  
Depth Information ◽  
Cumulative Error ◽  
Loop Detection ◽  
Probability Graph

The novel contribution of this paper is to propose an incremental pose map optimization for monocular vision simultaneous localization and mapping (SLAM) based on similarity transformation, which can effectively solve the scale drift problem of SLAM for monocular vision and eliminate the cumulative error by global optimization. With the method of mixed inverse depth estimation based on a probability graph, the problem of the uncertainty of depth estimation is effectively solved and the robustness of depth estimation is improved. Firstly, this paper proposes a method combining the sparse direct method based on histogram equalization and the feature point method for front-end processing, and the mixed inverse depth estimation method based on a probability graph is used to estimate the depth information. Then, a bag-of-words model based on the mean initialization K-means is proposed for closed-loop feature detection. Finally, the incremental pose map optimization method based on similarity transformation is proposed to process the back end to optimize the pose and depth information of the camera. When the closed loop is detected, global optimization is carried out to effectively eliminate the cumulative error of the system. In this paper, indoor and outdoor environmental experiments are carried out using open data sets, such as TUM and KITTI, which fully proves the effectiveness of this method. Closed-loop detection experiments using hand-held cameras verify the importance of closed-loop detection. This method can effectively solve the scale drift problem of monocular vision SLAM and has strong robustness.

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