Algorithms of Terminal Control of Multi-Copters

2019 ◽  
Vol 20 (1) ◽  
pp. 44-51 ◽  
Author(s):  
V. Kh. Pshikhopov ◽  
M. Yu. Medvedev ◽  
B. V. Gurenko
Keyword(s):  
Finite Time ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Moving Object ◽  
Target Point ◽  
Terminal Control ◽  
Current Position ◽  
Mobile Objects ◽  
Second Stage ◽  
Thrust And Torque

The article is devoted to the development of algorithms for terminal control of mobile objects. A moving object of multicopter type described by a nonlinear model of motion of a solid body in three-dimensional space is considered. A three-stage procedure for solving the problem of terminal control of a moving object when it moves to a given point is proposed. The main difference of the proposed procedure is the correction of the desired trajectory so that it passes through the current position of the moving object at each moment of time. This method of constructing the desired trajectory allows you to automatically adjust the speed when moving to a given point. The need for correction of the desired trajectory can be caused by the presence of obstacles, differences between the model and the real object, and the influence of external disturbances. At the first stage, the desired trajectory taking into account a given finite time of motion is constructed. The motion trajectory represents the desired velocity and orientation angles of a moving object of multi-copter type. At the second stage, the method of position-trajectory control is used to synthesize feedback, which provides stabilization of the moving object relative to the calculated desired trajectory. The result of the second stage is the thrust and torque generated by the motors, which are then recalculated in the speed of rotation of the rotors. At the third stage, the desired trajectory is corrected depending on the current position of the moving object. As a result of the correction, a singularity occurs at the target point. In order to eliminate the singularity at the target point, the problem is solved in the formulation of weak terminal control. Before the target point hits the given neighborhood, the velocity of the moving object is calculated based on the remaining distance and time of movement. When a given neighborhood of the target point is reached, the speed of movement becomes constant. The analysis of the closed-loop system is carried out, as a result of which the asymptotic stability of the desired trajectory and the hit of a moving object in a finite given neighborhood of the target point at a finite time are shown. The results of numerical modeling, confirming the performance of the proposed algorithms in the example of hexacopter, are presented.

Influence of Ball and Background Patterns on Perception of Visual Direction of a Moving Object

1979 ◽  
Vol 49 (2) ◽  
pp. 343-346 ◽  
Author(s):  
Marcella V. Ridenour
Keyword(s):  
Analysis Of Variance ◽  
Moving Objects ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Moving Object ◽  
Visual Direction ◽  
Visual Patterns ◽  
Prediction Time ◽  
The Subject ◽  
Three Dimensional Space

30 boys and 30 girls, 6 yr. old, participated in a study assessing the influence of the visual patterns of moving objects and their respective backgrounds on the prediction of objects' directionality. An apparatus was designed to permit modified spherical objects with interchangeable covers and backgrounds to move in three-dimensional space in three directions at selected speeds. The subject's task was to predict one of three possible directions of an object: the object either moved toward the subject's midline or toward a point 18 in. to the left or right of the midline. The movements of all objects started at the same place which was 19.5 ft. in front of the subject. Prediction time was recorded on 15 trials. Analysis of variance indicated that visual patterns of the moving object did not influence the prediction of the object's directionality. Visual patterns of the background behind the moving object did not influence the prediction of the object's directionality except during the conditions of a light nonpatterned moving object. It was concluded that visual patterns of the background and that of the moving object have a very limited influence on the prediction of direction.

scholarly journals Two-Stage Discrete Mechanical Modelin Three-Dimensional Space for Garment Simulation

2019 ◽  
Vol 19 (1) ◽  
pp. 26-35 ◽  
Author(s):  
Xuan Luo ◽  
Gaoming Jiang ◽  
Honglian Cong
Keyword(s):  
Mechanical Model ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Mathematical Expression ◽  
Two Stage ◽  
Second Stage ◽  
Simulation Speed ◽  
Optimal Value ◽  
Variable Distance ◽  
Stage Process

Abstract This paper focuses on the better performance between the garment simulation result and the simulation speed. For simplicity and clarity, a notation “PART” is defined to indicate the areas between the garment and the human body satisfying some constraints. The discrete mechanical model can be achieved by the two-stage process. In the first stage, the garment can be divided into several PARTs constrained by the distance. In the second stage, the mechanical model of each PART is formulated with a mathematical expression. Thus, the mechanical model of the garment can be obtained. Through changing the constrained distance, the simulation result and the simulation speed can be observed. From the variable distance, a desired value can be chosen for an optimal value. The results of simulations and experiments demonstrate that the better performance can be achieved at a higher speed by saving runtime with the acceptable simulation results and the efficiency of the proposed scheme can be verified as well.

scholarly journals Optimization Design of a 2.5 Stage Highly Loaded Axial Compressor with a Bezier Surface Modeling Method

2020 ◽  
Vol 10 (11) ◽  
pp. 3860
Author(s):  
Song Huang ◽  
Jinxin Cheng ◽  
Chengwu Yang ◽  
Chuangxin Zhou ◽  
Shengfeng Zhao ◽  
...  
Keyword(s):  
Flow Field ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Axial Compressor ◽  
High Dimensions ◽  
Peak Efficiency ◽  
Stall Margin ◽  
Second Stage ◽  
Highly Loaded ◽  
Three Dimensional Space

Due to the complexity of the internal flow field of compressors, the aerodynamic design and optimization of a highly loaded axial compressor with high performance still have three problems, which are rich engineering design experience, high dimensions, and time-consuming calculations. To overcome these three problems, this paper takes an engineering-designed 2.5-stage highly loaded axial flow compressor as an example to introduce the design process and the adopted design philosophies. Then, this paper verifies the numerical method of computational fluid dynamics. A new Bezier surface modeling method for the entire suction surface and pressure surface of blades is developed, and the multi-island genetic algorithm is directly used for further optimization. Only 32 optimization variables are used to optimize the rotors and stators of the compressor, which greatly overcome the problem of high dimensions, time-consuming calculations, and smooth blade surfaces. After optimization, compared with the original compressor, the peak efficiency is still improved by 0.12%, and the stall margin is increased by 2.69%. The increase in peak efficiency is mainly due to the rotors. Compared with the original compressor, for the second-stage rotor, the adiabatic efficiency is improved by about 0.4%, which is mainly due to the decreases of total pressure losses in the range of above 30% of the span height and 10%–30% of the chord length. Besides, for the original compressor, due to deterioration of the flow field near the tip region of the second-stage stator, the large low-speed region eventually evolves from corner separation into corner stall with three-dimensional space spiral backflow. For the optimized compressor, the main reason for the increased stall margin is that the flow field of the second-stage stator with a span height above 50% is improved, and the separation area and three-dimensional space spiral backflow are reduced.

scholarly journals Multi-attribute interactive visualization of three-dimensional trajectory sets

2021 ◽  
Vol 48 (4) ◽  
Author(s):  
Jing He ◽  
◽  
Haonan Chen ◽  
Keyword(s):  
Dimensional Space ◽  
Spatial Scales ◽  
Three Dimensional ◽  
Spatial Location ◽  
Spatiotemporal Analysis ◽  
Moving Object ◽  
Dynamic Visualization ◽  
Location Awareness ◽  
Trajectory Data ◽  
Attribute Information

Rapidly advancing location-awareness technologies and services have collected and stored massive amounts of moving object trajectory data with attribute information that involves various degrees of spatial scales, timescales, and levels of complexity. Unfortunately, interesting behaviors regarding combinations of attributes are scarcely extracted from datasets. Further, trajectories are typically dependent on the environment of three-dimensional space, and another issue of interest to us is to preserve spatial-location visualization while guaranteeing the description of temporal information. Therefore, we developed a novel analytics tool that combines visual and interactive components to enable a dynamic visualization of three-dimensional trajectory multi-attribute behaviors. Under the context of spatiotemporal analysis, this approach integrates multiple attributes into one view to efficiently explore the attribute visualization problem of multi-attribute combination without over-plotting. To assess the feasibility of our solution, we visualized and analyzed multi-attribute information of moving object trajectories using a real mining truck dataset as a case study.

scholarly journals The sophisticated visual system of a tiny Cambrian crustacean: analysis of a stalked fossil compound eye

2011 ◽  
Vol 279 (1732) ◽  
pp. 1335-1340 ◽  
Author(s):  
Brigitte Schoenemann ◽  
Christopher Castellani ◽  
Euan N. K. Clarkson ◽  
Joachim T. Haug ◽  
Andreas Maas ◽  
...  
Keyword(s):  
Moving Objects ◽  
Compound Eye ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Contralateral Side ◽  
Moving Object ◽  
Compound Eyes ◽  
Optical Axes ◽  
The Right ◽  
Deep Cavities

Fossilized compound eyes from the Cambrian, isolated and three-dimensionally preserved, provide remarkable insights into the lifestyle and habitat of their owners. The tiny stalked compound eyes described here probably possessed too few facets to form a proper image, but they represent a sophisticated system for detecting moving objects. The eyes are preserved as almost solid, mace-shaped blocks of phosphate, in which the original positions of the rhabdoms in one specimen are retained as deep cavities. Analysis of the optical axes reveals four visual areas, each with different properties in acuity of vision. They are surveyed by lenses directed forwards, laterally, backwards and inwards, respectively. The most intriguing of these is the putatively inwardly orientated zone, where the optical axes, like those orientated to the front, interfere with axes of the other eye of the contralateral side. The result is a three-dimensional visual net that covers not only the front, but extends also far laterally to either side. Thus, a moving object could be perceived by a two-dimensional coordinate (which is formed by two axes of those facets, one of the left and one of the right eye, which are orientated towards the moving object) in a wide three-dimensional space. This compound eye system enables small arthropods equipped with an eye of low acuity to estimate velocity, size or distance of possible food items efficiently. The eyes are interpreted as having been derived from individuals of the early crustacean Henningsmoenicaris scutula pointing to the existence of highly efficiently developed eyes in the early evolutionary lineage leading towards the modern Crustacea.

Base Algorithms of the Direct Adaptive Position-Path Control for Mobile Objects Positioning

2015 ◽  
Vol 763 ◽  
pp. 110-119 ◽  
Author(s):  
Viacheslav Pshikhopov ◽  
Mikhail Medvedev ◽  
Victor Krukhmalev ◽  
Victor Shevchenko
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Reference Model ◽  
Block Diagram ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Mobile Object ◽  
Mobile Objects ◽  
Closed Loop Systems ◽  
Path Control

Problem of a mobile object positioning in the presence of determinate disturbances is considered in this paper. A mobile object is described by kinematics and dynamics equations of a solid body in three dimensional space. The control inputs of the mobile object are forces and torques. Design of adaptive control is based on position-path control method for mobile objects. In this article two algorithms of the adaptive position-path control are developed. The first algorithm is adaptive position-path control with integration component and a reference model. The second algorithm is adaptive position-path control with a reference model and an extended mobile robot model. Block diagram of the direct adaptive position-path control system with a reference model is suggested. Design procedures of the adaptive position-path control systems and stability analysis of the closed-loop systems are presented. Computer simulation results of the designed adaptive closed-loop systems with both constant and variable disturbances are presented. On base of the analysis and modeling results conclusions are provided.

New three-dimensional second-order sliding mode guidance law with impact-angle constraints

2019 ◽  
Vol 124 (1273) ◽  
pp. 368-384
Author(s):  
F.-J. Zhao ◽  
H. You
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Impact Angle ◽  
Second Order ◽  
Singular Problem ◽  
Guidance Law ◽  
Coupling Terms ◽  
Second Order Sliding Mode

AbstractAiming at the issue of missiles attacking on-ground maneuvering targets in three-dimensional space, a three-dimensional finite-time guidance law with impact-angle constraints is proposed. In order to improve convergence speed and restrain chattering phenomenon, the nonsingular fast terminal three-dimensional second-order sliding mode guidance law with coupling terms is designed based on the theory of nonhomogeneous fast terminal sliding surface and second-order sliding mode control. The system model need not be linearized during the design process, and the singular problem is avoided. A nonhomogeneous disturbance observer is designed to estimate and compensate the total disturbance, which is caused by target maneuvering information and coupling terms of line of sight. And the stability and finite-time convergence of the guidance law are proved strictly and mathematically. Finally, simulation results have verified the effectiveness and superiority of the proposed guidance law.

Three Dimensional structure and organization of diploid chromosomes by optical section microscopy

1987 ◽  
Vol 45 ◽  
pp. 633-635
Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Developmental State ◽  
Mitotic Cell ◽  
Biological Properties ◽  
Dimensional Structure ◽  
Specific Gene ◽  
Three Dimensional Structure ◽  
Complementary Techniques ◽  
Dynamic Structures

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.

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