scholarly journals Dynamic Calculation of a Steering Control of Gantry High-Clearance Tractor Used in Horticulture and Viticulture

2020 ◽  
Vol 9 (7) ◽  
pp. 762-768
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Hydraulic Cylinder ◽  
Steering Control ◽  
Dynamic Calculation ◽  
Hydraulic Steering ◽  
Steering Mechanism ◽  
High Clearance

The article presents a mathematical model and the results of dynamic calculation of hydraulic steering control of a four-wheel gantry high-clearance tractor, consisting of a distributor, pipelines and a steering mechanism – a hydraulic cylinder. The results of pressure and flow rate changes in the hydraulic cylinder are presented. The results of dynamic calculation can be used to study the process of turning movement of a tractor.

scholarly journals A mathematical model of the steering wheel skidder

2018 ◽  
Author(s):  
Х.Ж. Као ◽  
А.М. Кочнев
Keyword(s):  
Mathematical Model ◽  
Dynamic Analysis ◽  
Dynamic Processes ◽  
Steering Wheel ◽  
Application Software ◽  
Steering Control ◽  
The Real ◽  
Hydraulic Steering ◽  
Direction Of Movement ◽  
Experimental Researches

Параметры рулевого управления трактора оказывают существенное влияние на его эксплуатационные свойства и, в первую очередь, на маневренность и устойчивость заданного направления движения, а также на утомляемость оператора. В основу выбора параметров рулевого управления должен быть положен динамический анализ. Цель исследования – разработка математической модели динамики гидросистемы рулевого управления колесных трелевочных тракторов. Для уточнения ряда параметров математической модели рулевого управления выполнен цикл экспериментальных исследований колесных трелевочных тракторов. Разработанная математическая модель работы рулевого управления колесных трелевочных тракторов, реализованная в виде пакета прикладных програма для ЭВМ, адекватна происходящим в нем реальным динамическим процессам и рекомендуется к использованию в АСНИ и САПР «Колесный трелевочный трактор» при исследовании и оптимизации параметров рулевого управления существующих и проектируемых тракторов для заготовки леса. The steering parameters of the tractor have a significant impact on its performance, and primarily on the maneuverability, stability of a given direction of movement, as well as fatigue of the operator. The choice of steering parameters should be based on dynamic analysis. The aim of the research is to develop a mathematical model of dynamics of hydraulic steering wheel skidders. For specification of a number of parameters of mathematical model of steering control the cycle of experimental researches of wheel skidders is executed. The developed mathematical model of steering wheel skidders, implemented in the form of a package of application software for computers, adequate to the real dynamic processes taking place in it and is recommended for use in ASNI and CAD «Wheel skidding tractor» in the study and optimization of steering parameters of existing and projected tractors for logging.

Research on an axial-mounted dual magnetostrictive material rods-based electro-hydrostatic actuator

2021 ◽  
pp. 1045389X2110145
Author(s):  
Yuchuan Zhu ◽  
Chang Liu ◽  
Yunze Song ◽  
Long Chen ◽  
Yulei Jiang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Flow Distribution ◽  
Maximum Flow ◽  
Magnetostrictive Material ◽  
Simulation Techniques ◽  
Motion State ◽  
New Type ◽  
Output Characteristics ◽  
Active Rectification

In this paper, an electro-hydrostatic actuator driven by dual axial-mounted magnetostrictive material rods-based pumps (MMPs) with a new type of active rectification valve is designed in the current study. Based on flow distribution of the active rectification valve and driving energy provided by two MMPs, the actuator can output continuous and bidirectional displacement. By establishing a mathematical model of the actuating system, using simulation techniques, the change rule of hydraulic cylinder’s motion state caused by different driving signals are studied and analyzed. Test equipment platform is constructed in the laboratory to test the output characteristics and confirm the feasibility of the new concept. The experimental results indicate that the maximum flow rate can reach approximately 2.7 L·min−1, while the operating frequency is 180 Hz.

scholarly journals A Mathematical Model for Swallowing of Concentrated Fluids in Oesophagus

2011 ◽  
Vol 8 (3-4) ◽  
pp. 309-321 ◽  
Author(s):  
S. K. Pandey ◽  
Dharmendra Tripathi
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Plug Flow ◽  
Flow Region ◽  
Mechanical Efficiency ◽  
Casson Fluid ◽  
Local Pressure ◽  
Integral Number ◽  
Tomato Puree ◽  
The Impact

This model investigates particularly the impact of an integral and a non-integral number of waves on the swallowing of food stuff such as jelly, tomato puree, soup, concentrated fruits juices and honey transported peristaltically through the oesophagus. The fluid is considered as a Casson fluid. Emphasis is on the study of the dependence of local pressure distribution on space and time. Mechanical efficiency, reflux limit and trapping are also discussed. The effect of Casson fluid vis-à-vis Newtonian fluid is investigated analytically and numerically too. The result is physically interpreted as that the oesophagus makes more efforts to swallow fluids with higher concentration. It is observed that the pressure is uniformly distributed when an integral number of waves is there in the oesophagus; but it is non-uniform when a non-integral number of waves is present therein. It is further observed that as the plug flow region widens, the pressure difference increases, which indicates that the averaged flow rate will reduce for a Casson fluid. It is also concluded that Casson fluids are more prone to reflux.

Mathematical model of pressure distribution in a main pipeline during pumping with the use of drug reducing agents, taking into account their degradation

2021 ◽  
pp. 396-406
Author(s):  
Мурсалим Мухутдинович Гареев ◽  
Марат Иозифович Валиев ◽  
Филипп А. Карпов
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Pressure Distribution ◽  
Flow Rate ◽  
Pressure Head ◽  
Petroleum Products ◽  
Reducing Agents ◽  
Main Pipeline ◽  
Main Mode ◽  
Pipeline Pressure

Путевая деградация противотурбулентных присадок (ПТП) может стать причиной изменения основных параметров режима магистрального трубопровода - давления и расхода - относительно установившихся значений и осложнить контроль их отклонений от нормативных показателей. При этом до настоящего момента отсутствовала методика расчета режимов перекачки при использовании ПТП с учетом деградации. Авторами была поставлена цель по разработке методики для математического описания распределения давления в трубопроводе с учетом путевой деградации присадки, а также при различных концентрациях ПТП. Для достижения указанной цели предлагается дополнить уравнение баланса напоров с учетом эмпирической зависимости эффективности присадки от длины трубопровода. При расчетах давления в промежуточных точках трассы предлагается использовать данные опытно-промышленных испытаний по изменению эффективности ПТП. Для иллюстрации применения методики рассматриваются примеры перекачки нефти и нефтепродуктов с добавлением присадок в различных концентрациях. На основании экспериментальных данных получена адекватная математическая модель снижения эффективности ПТП по длине магистрального трубопровода для различных концентраций вводимой присадки. Path degradation of drug reducing agents (DRA) can cause changes in the main mode parameters of the main pipeline; pressure and flow rate, relative to the stable values, and complicate the adjustment of their deviations from the standard indicators. At the same time, up until now there has been no methodology for calculating pumping modes when using DRA that takes degradation into account. The authors set a goal to develop a methodology to mathematically describe the pressure distribution in the pipeline, taking into account the path degradation of the agent, as well as the parameters at different DRA concentrations. To achieve this goal, it is proposed to supplement the equation of the pressure head balance with the empirical dependency of agent efficiency on the length of the pipeline. When calculating the pressure at intermediate points of the route, it is proposed to use the pilot run data on the change in the DRA efficiency. To illustrate the application of the methodology, examples of pumping oil and petroleum products with added agents in various concentrations are discussed. On the basis of the experimental data, an adequate mathematical model of the DRA efficiency reduction along the length of the main pipeline for different concentrations of introduced agent was obtained.

scholarly journals Analysis of Platform Leveling Systems for Tracked Feller-Buncher Machines

Inventions ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 96
Author(s):  
Andronov Alexandr ◽  
Bacherikov Ivan ◽  
Zverev Igor
Keyword(s):  
Mathematical Model ◽  
Center Of Mass ◽  
Slope Angle ◽  
Hydraulic Cylinder ◽  
Second Stage ◽  
Modeling Methods ◽  
The Third ◽  
Support Reaction ◽  
Third Stage ◽  
The Stability

The study was devoted to the analysis of feller buncher platform leveling systems. The widespread use of these systems in the design of modern feller-buncher machines makes the study relevant to assess operational efficiency. The analysis was conducted in five stages using analytical and stochastic mathematical modeling methods. In the first stage, the existing layouts of alignment systems were analyzed from the position of force on the hydraulic cylinder rods of the platform tilt drive. The three-cylinder layout scheme, where the force on the hydraulic cylinder rod was 50…60% less than that on the two-cylinder layout, appeared to be the most expedient. In the second stage, a mathematical model for determining changes in the position of the center of mass of the feller-buncher depending on the inclination angle of the platform was derived. In the third stage, a mathematical model was derived for determining the limiting angle of slope of the terrain when the feller buncher moved up the slope. For this purpose, two calculation schemes were considered when the machine moved up the slope without and with a tilted platform. Zero support reaction on the front roller was taken as the stability criterion. In the fourth stage, a mathematical model for determining the limiting angle of slope of the terrain during the roll of the feller-buncher machine was obtained. In the fifth stage, the efficiency of the application of leveling systems was evaluated. A graph of the dependence of changes in the terrain slope angle on the platform slope angle was plotted, and a regression dependence for an approximate estimate was obtained. A regression analysis was also carried out, and dependencies were obtained to determine the weight of a feller-buncher with a leveling system and the added pressure on the ground caused by the increase in the weight of the base machine. The analysis of platform leveling systems showed the effectiveness of their application in the designs of feller-buncher machines, as it allows the machines to work on slopes with an inclination of 50…60% more than without them.

scholarly journals Assessment of a mathematical model considering the effect of flow rate on in-vitro drug-release from PLGA films

2021 ◽  
Vol 321 ◽  
pp. 04011
Author(s):  
Navideh Abbasnezhad ◽  
Farid Bakir ◽  
Stéphane Champmartin ◽  
Mohammadali Shirinbayan
Keyword(s):  
Mathematical Model ◽  
Drug Release ◽  
Flow Rate ◽  
Drug Carrier ◽  
Diclofenac Sodium ◽  
Drug Eluting Stents ◽  
In Vitro Drug Release ◽  
Drug Eluting ◽  
Release Profiles

Drug-eluting stents implanted in blood vessels are subject to various dynamics of blood flow. In this study, we present the evaluation of a mathematical model considering the effect of flow rate, to simulate the kinetic profiles of drug release (Diclofenac Sodium (DS)) from in-vitro from PLGA films. This model solves a set of non-linear equation for modeling simultaneously the burst, diffusion, swelling and erosion involved in the mechanisms of liberation. The release parameters depending on the flow rate are determined using the corresponding mathematical equations. For the evaluation of the proposed model, test data obtained in our laboratory are used. To quantify DS release from drug-carrier PLGA films, we used the flow-through cell apparatus in a closed-loop. Four flow rate values are applied. For each value, the model-substance liberation kinetics showed an increase in drug released with the flow rate. The simulated release profiles show good agreement with the experimental results. Therefore, the use of this model could provide a practical tool to assess in-vitro drug release profiles from polymer matrices under continuous flow rate constraint, and could help improve the design of drug eluting stents.

Test Analysis of a Six-Wheel Hydraulic Active Suspension Control System

2012 ◽  
Vol 591-593 ◽  
pp. 1710-1714
Author(s):  
Wei Chen ◽  
Zhi Yao ◽  
Qing Bo Zhao ◽  
Tong Jian Wang
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Active Suspension ◽  
Hydraulic Cylinder ◽  
Suspension System ◽  
Quantitative Feedback Theory ◽  
Test Analysis ◽  
Suspension Control ◽  
System Robustness ◽  
Road Performance

In order to make the active hydraulic suspension system to adaptive the ground. Taking the asymmetric valve controlled hydraulic cylinder as actuators, a six wheels hydraulic active suspension was designed. It is difficult to analysis of the six wheels system. So this paper established the single wheel’s mathematical model to instead analysis of the whole system, designed QFT (Quantitative Feedback Theory) controller which can be a solution to the system robustness, researched the hydraulic active suspension system. The results show that it is good for tracking performance of the hydraulic cylinder which taking the asymmetric valve controlled as actuators, system responses timely and the controller can meet the controlling requirements. This hydraulic active suspension system can improve off-road performance of engineering vehicles.

Sign in / Sign up

Export Citation Format

Share Document