scholarly journals Synthesis of a time-optimal control system for an extremal object

2021 ◽  
Vol 2090 (1) ◽  
pp. 012011
Author(s):  
G.A. Pikina ◽  
F.F. Pashchenko ◽  
A.F. Pashchenko
Keyword(s):  
Synthesis Method ◽  
State Variables ◽  
Third Order ◽  
Canonical Variables ◽  
System A ◽  
Control Interval ◽  
Canonical State ◽  
Time Optimal ◽  
Real Objects ◽  
Direction Of Movement

Abstract The paper presents the derivation of the synthesis method for the algorithm of the time-optimal controller for a third order dynamic system. A model with an extreme second-order transient response with delay was adopted as an object of research. The constant speed actuator is represented by an integrator. The synthesis is based on using the Pontryagin’s maximum principle and describing the dynamics of a system in the state space using canonical variables. The verification of the correctness of the result obtained by the theorem of Feldbaum A.A. on the number of switchings of the direction of movement of the regulating body during the control interval has been executed. To calculate the canonical state variables, it is proposed to use the position of the regulator, the controlled value and the derivative calculated from its values, measured on real objects.

Switching Strategy for Optimal Adaptive Third Order Control Systems

1970 ◽  
Vol 3 (10) ◽  
pp. T168-T172
Author(s):  
Satish C. Mohleji ◽  
Paul A. V. Thomas
Keyword(s):  
Control Systems ◽  
State Variables ◽  
Optimal Switching ◽  
Optimal Control Strategy ◽  
Actual System ◽  
Third Order ◽  
Time Optimal ◽  
The Difference ◽  
Bang Bang Control ◽  
Derivatives Of

The conventional design of bang bang control systems for time optimal performance involves an accurate mathematical model of the system and complex computations to determine the optimal switching conditions. Such a design is normally based on the assumption that the system parameters remain fairly constant. Recomputation of optimal trajectories becomes necessary for any change in the parameters. This paper describes a simple adaptive-optimal control strategy for systems representable in phase space and can be easily adopted on a digital controller. Projections of optimal curves are obtained by storing sections of actual system trajectories in the form of tables in the computer memory. Optimal switching instants are determined by shifting and comparing the stored trajectory with the actual trajectory. Since no manipulations are required and the switching curves are obtained by constantly storing and updating the system trajectories, the control remains optimum even when there is a change in parameters. The proposed strategy requires only measurement of error in the system, derivatives of error are formed by using the difference equations, a method well suited for digital formulation of state variables.

scholarly journals Measurement of Gem Colour Using a Computer Vision System: A Case Study with Jadeite-Jade

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 791
Author(s):  
Sufei Zhang ◽  
Ying Guo
Keyword(s):  
Computer Vision ◽  
Regression Model ◽  
Vision System ◽  
Expert Group ◽  
Group Test ◽  
System A ◽  
Real Objects ◽  
Practical Tool ◽  
Almost All

This paper introduces computer vision systems (CVSs), which provides a new method to measure gem colour, and compares CVS and colourimeter (CM) measurements of jadeite-jade colour in the CIELAB space. The feasibility of using CVS for jadeite-jade colour measurement was verified by an expert group test and a reasonable regression model in an experiment involving 111 samples covering almost all jadeite-jade colours. In the expert group test, more than 93.33% of CVS images are considered to have high similarities with real objects. Comparing L*, a*, b*, C*, h, and ∆E* (greater than 10) from CVS and CM tests indicate that significant visual differences exist between the measured colours. For a*, b*, and h, the R2 of the regression model for CVS and CM was 90.2% or more. CVS readings can be used to predict the colour value measured by CM, which means that CVS technology can become a practical tool to detect the colour of jadeite-jade.

scholarly journals A Boom Energy Regeneration System of Hybrid Hydraulic Excavator Using Energy Conversion Components

Actuators ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
Tri Cuong Do ◽  
Duc Giap Nguyen ◽  
Tri Dung Dang ◽  
Kyoung Kwan Ahn
Keyword(s):  
Management Strategy ◽  
Electrical Energy ◽  
Maximum Energy ◽  
Regeneration System ◽  
Hydraulic Pump ◽  
Energy Management Strategy ◽  
Energy Regeneration ◽  
System A ◽  
Time Optimal ◽  
Novel Design

In this paper, a novel design of an energy regeneration system was proposed for recovering as well as reusing potential energy in a boom cylinder. The proposed system included a hydraulic pump/motor and an electrical motor/generator. When the boom moved down, the energy regeneration components converted the hydraulic energy to electrical energy and stored in a battery. Then, the regenerated energy was reused at subsequent cycles. In addition, an energy management strategy has been designed based on discrete time-optimal control to guarantee position tracking performance and ensure component safety during the operation. To verify the effectiveness of the proposed system, a co-simulation (using MATLAB and AMESim) was carried out. Through the simulation results, the maximum energy regeneration efficiency could achieve up to 44%. Besides, the velocity and position of the boom cylinder achieved good performance with the proposed control strategy.

scholarly journals Tunable Nonlinear Optical Property of MnS Nanoparticles with Different Size and Crystal Form

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 34
Author(s):  
Zhihao Zhang ◽  
Pengchao Li ◽  
Yuzong Gu
Keyword(s):  
Optical Property ◽  
Nonlinear Optical ◽  
Nonlinear Optical Property ◽  
Nonlinear Refraction ◽  
Synthesis Method ◽  
Crystal Form ◽  
Optical Nonlinearity ◽  
Photon Absorption ◽  
Third Order ◽  
Crystal Forms

It is significant to study the reason that semiconductor material has adjustable third-order optical nonlinearity through crystal form and dimensions are changed. αMnS nanoparticles with different crystal forms and sizes were successfully prepared by one-step hydrothermal synthesis method and their size-limited third-order nonlinear optical property was tested by Z-scan technique with 30 ps laser pulses at 532 nm wavelength. Nanoparticles of different crystal forms exhibited different NLO (nonlinear optical) responses. γMnS had stronger NLO response than αMnS because of higher fluorescence quantum yield. Two-photon absorption and the nonlinear refraction are enhanced as size of nanoparticlesreduced. The nanoparticles had maximum NLO susceptibility which was 3.09 × 10−12 esu. Susceptibility of αMnS increased about nine times than that of largest nanoparticles. However, it was reduced when size was further decreased. This trend was explained by the effects of light induced dipole moments. And defects in αMnS nanoparticles also had effect on this nonlinear process. MnS nanoparticles had potential application value in optical limiting and optical modulation.

scholarly journals Crop growth models without hormones.

1983 ◽  
Vol 31 (4) ◽  
pp. 313-323 ◽  
Author(s):  
C.T. de Wit ◽  
F.W.T.P. de Vries
Keyword(s):  
Dynamic Models ◽  
Dynamic Equilibrium ◽  
Growth Models ◽  
Co2 Assimilation ◽  
Crop Growth ◽  
State Variables ◽  
System A ◽  
Similar Information ◽  
Hormonal System ◽  
Crop Growth Models

For the simulation of organ formation and assimilate partitioning, information is required on the current level of activities like CO2 assimilation and the growth of various organs, as well as state variables such as leaf and root wt., N content and carbohydrate reserves and exogenous variables like radiation and temp. This information may be retained in auxiliary state variables by considering the dynamic equilibrium between growth of roots and shoots. Auxiliary state variables are not tangible quantities but mathematical artefacts of the simulation program; it is speculated that in real plants similar information may be retained and transferred by the hormonal system. A hormonal system is a communication system and such systems may be analysed either in terms of means (of the hardware used) or in terms of purpose (of the messages transferred). In dynamic models of crop growth, interest should be focused on the latter. Wheat, maize and ryegrass are used as examples. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Lateral vibration control of a shafting-hull coupled system with electromagnetic bearings

2018 ◽  
Vol 38 (1) ◽  
pp. 154-167 ◽  
Author(s):  
Hui Qin ◽  
Hongbo Zheng ◽  
Wenyuan Qin ◽  
Zhiyi Zhang
Keyword(s):  
Frequency Response ◽  
Acoustic Radiation ◽  
Synthesis Method ◽  
Coupled System ◽  
Lateral Vibration ◽  
Vibration Transmission ◽  
Lateral Vibrations ◽  
System A ◽  
Vibration Responses ◽  
Stiffness And Damping

In order to suppress lateral vibration transmission and reduce acoustic radiation of a shafting-hull coupled system, a new approach using electromagnetic bearings in the shafting system is proposed. The dynamic characteristics of the electromagnetic bearings, especially the equivalent stiffness and damping as well as the applicable scope of linearization of the electromagnetic bearings, are analysed at first. With the equivalent parameters, a dynamic model of the shafting-hull coupled system is established subsequently by using the frequency response synthesis method to derive frequency response functions associated with the lateral vibrations. Finally, the influence of the control parameters of the electromagnetic bearings on vibration transmission in the shafting-hull system is studied. Analysis results indicate that lateral vibration responses are suppressed significantly when electromagnetic bearings are introduced into the shafting-hull system, and as a result, sound radiation of the system is reduced, which demonstrates that the proposed approach is effective in controlling vibration transmission in the shafting system.

Constructing Poisson and Dissipative Brackets of Mixtures by using Lagrangian-to-Eulerian Transformation

2010 ◽  
Vol 26 (2) ◽  
pp. 219-228
Author(s):  
K.-C. Chen
Keyword(s):  
Evolution Equations ◽  
Poisson Brackets ◽  
State Variables ◽  
Component Mixture ◽  
Dissipative Part ◽  
Canonical Variables ◽  
Lagrangian Variable ◽  
Two Component ◽  
Lagrangian Form

AbstractThis paper aims to construct the bracket formalism of mixture continua by using the method of Lagrangian- to-Eulerian (LE) transformation. The LE approach first builds up the transformation relations between the Eulerian state variables and the Lagrangian canonical variables, and then transforms the bracket in Lagrangian form to the bracket in Eulerian form. For the conservative part of the bracket formalism, this study systematically generates the noncanonical Poisson brackets of a two-component mixture. For the dissipative part, we deduce the Eulerian-variable-based dissipative brackets for viscous and diffusive mechanisms from their Lagrangian-variable-based counterparts. Finally, the evolution equations of a micromorphic fluid, which can be treated as a multi-component mixture, are derived by constructing its Poisson and dissipative brackets.

Weakly Nonlinear Mass Transfer in an Internally Soluted and Modulated Porous Layer

2020 ◽  
Vol 12 (5) ◽  
pp. 622-631
Author(s):  
Palle Kiran ◽  
S. H. Manjula
Keyword(s):  
Mass Transfer ◽  
Solvability Condition ◽  
Finite Amplitude ◽  
Amplitude Equation ◽  
Third Order ◽  
Weakly Nonlinear ◽  
Weakly Nonlinear Analysis ◽  
System Parameters ◽  
System A ◽  
Rotating Porous Media

The effect of solutal modulation on a rotating porous media is studied. Using solvability condition, the finite amplitude equation is derived at third order of the system. A weakly nonlinear analysis is applied to investigate mass transfer in a porous medium. In this article, the stationary convection is discussed in the presence of solutal Rayleigh number. The amplitude equation (GLE) is solved numerically. Using this GLE the Sherwood number is evaluated in terms of the various system parameters. The effect of individual parameters on mass transport is discussed in detail. It is found that the mass transfer is more for modulated system than un-modulated case. Further, internal solute number Si enhance or diminishes the mass transfer. Finally it is also found that, solutal modulation can be effectively applied in either enhancing or diminishing the mass transfer.

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