scholarly journals Active Disturbance Rejection Control of Underwater Vehicle with Omnidirectional Control

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wen-Qing Zhang ◽  
Liang-Long Da ◽  
Wu-Hong Guo ◽  
Yong Lv ◽  
Mei Han
Keyword(s):  
Disturbance Rejection ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Control Power ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control ◽  
Symmetry Structure ◽  
Omnidirectional Control ◽  
Output Equation ◽  
Three Dimensional Space

This paper focuses on the omnidirectional drive characteristics and autonomous control of the underwater saucer glider under the condition of underactuated and multiconstraints. Firstly, the dynamic model of the underwater saucer glider is established, and the underactuated control characteristics and the plane biaxial symmetry structure characteristics of the underwater saucer glider are analyzed. An omnidirectional drive mechanism with four water jet thrusters is designed, and the omnidirectional control power output equation is given. Secondly, a nonlinear active disturbance rejection controller is designed, and a visual simulation platform of UUVs based on MATLAB + MFC is established. Through a large number of numerical tests, the reliability and effectiveness of the control strategy are verified, and the smooth operation of the underwater saucer glider in the dynamic process of three-dimensional space is realized.

scholarly journals Measurement Compensation for Time-Delay Seeker and Three-Dimensional Adaptive Guidance Law Design

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3977
Author(s):  
Yukuan Liu ◽  
Guanglin He ◽  
Zenghui Qiao ◽  
Zhaoxuan Guo ◽  
Zehu Wang
Keyword(s):  
Disturbance Rejection ◽  
Sliding Mode ◽  
Three Dimensional ◽  
Compensation System ◽  
Active Disturbance Rejection Control ◽  
Missile Guidance ◽  
Guidance Law ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control ◽  
Twisting Algorithm

The time delay of seekers has grown to be a serious issue for tactical missile guidance with the development of flight vehicle technologies. To address the problem, a measurement compensation system for the seeker, with lags and delays based on predictive active disturbance rejection control, is proposed. In addition, to eliminate the effects of target maneuvers to the tactical missile guidance, an adaptive finite-time convergent sliding mode guidance law, based on super-twisting algorithm, is proposed in three-dimensional missile-target engagement kinematics. Specifically, the compensation system consists of a predictive tracking structure and an active disturbance rejection control system, which could follow a virtual measurement without lags and delays. The compensation system has advantages in disturbance rejection and model inaccuracy addressing, compared with existing compensation methods for seeker measurement. As for the sliding mode guidance law design, the proposed approach is based on an improved super-twisting algorithm with fast convergent adaptive gains, which has advantages in addressing unknown but bounded target maneuvers and avoiding chattering of the classical sliding mode control. As a result, the measurement compensation system and the adaptive sliding mode guidance law is verified robust and effective under the proposed constraints by the simulation examples.

Extension of the Spatial PDI Model to Three Dimensions

1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien
Keyword(s):  
Population Density ◽  
Dimensional Space ◽  
Finite Lattice ◽  
Three Dimensional ◽  
Upper Bounds ◽  
Three Dimensions ◽  
Lower And Upper Bounds ◽  
Density Index ◽  
Three Dimensional Space

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.

A Peptoid with Extended Shape in Water

2019 ◽  
Author(s):  
Jumpei Morimoto ◽  
Yasuhiro Fukuda ◽  
Takumu Watanabe ◽  
Daisuke Kuroda ◽  
Kouhei Tsumoto ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Biomolecular Recognition ◽  
Biological Application ◽  
New Class ◽  
Proteolytic Resistance ◽  
Pharmacokinetic Properties ◽  
Optically Pure ◽  
Three Dimensional Space

<div> <div> <div> <p>“Peptoids” was proposed, over decades ago, as a term describing analogs of peptides that exhibit better physicochemical and pharmacokinetic properties than peptides. Oligo-(N-substituted glycines) (oligo-NSG) was previously proposed as a peptoid due to its high proteolytic resistance and membrane permeability. However, oligo-NSG is conformationally flexible and is difficult to achieve a defined shape in water. This conformational flexibility is severely limiting biological application of oligo-NSG. Here, we propose oligo-(N-substituted alanines) (oligo-NSA) as a new peptoid that forms a defined shape in water. A synthetic method established in this study enabled the first isolation and conformational study of optically pure oligo-NSA. Computational simulations, crystallographic studies and spectroscopic analysis demonstrated the well-defined extended shape of oligo-NSA realized by backbone steric effects. The new class of peptoid achieves the constrained conformation without any assistance of N-substituents and serves as an ideal scaffold for displaying functional groups in well-defined three-dimensional space, which leads to effective biomolecular recognition. </p> </div> </div> </div>

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