Kinematics and Dynamics of a Sliding/Bouncing Two Mass System

2011 ◽  
Author(s):  
Mohamed Gharib ◽  
Ali Tavakoli ◽  
Yildirim Hurmuzlu
Keyword(s):  
Slope Angle ◽  
Surface Friction ◽  
Correlation Ratio ◽  
Constrained Motion ◽  
Mass System ◽  
Inclined Planes ◽  
Ground Impact ◽  
The Impact ◽  
Wall Slope ◽  
Impact Problem

This paper presents the solution of the impact problem for a sliding/bouncing baton on flat and inclined planes subject to surface friction. The baton is assumed to have unilaterally constrained motion, which means one end slides on the ground while the other end collides with the ground. We use the impulse momentum approach and incorporate the impulse correlation ratio (ICR) hypothesis to solve the ground impact problem when the system has unilaterally constrained dynamics. Parametric investigations were carried out to examine the effect of the baton’s length and the inclined wall slope angle on the impulse correlation ratio. Numerical simulation and experiments were carried out to validate the model.

Collision of Two Mass Baton With Massive External Surfaces

2012 ◽  
Vol 79 (5) ◽  
Author(s):  
Ali Tavakoli ◽  
Mohamed Gharib ◽  
Yildirim Hurmuzlu
Keyword(s):  
Slope Angle ◽  
Surface Friction ◽  
Correlation Ratio ◽  
Constrained Motion ◽  
Surface Slope ◽  
Inclined Planes ◽  
Ground Impact ◽  
The Impact ◽  
Inclined Surface ◽  
Impact Problem

This paper presents the solution of the impact problem for a sliding/bouncing baton on flat and inclined planes subject to surface friction. The baton is assumed to have unilaterally constrained motion, which means one end slides on the ground while the other end collides with the ground. We use the impulse momentum approach and incorporate the impulse correlation ratio (ICR) hypothesis to solve the ground impact problem when the system has unilaterally constrained dynamics. Parametric investigations were carried out to examine the effect of the baton’s length and the inclined surface slope angle on the impulse correlation ratio. Numerical simulation and experiments were carried out to validate the model.

scholarly journals Existing Improvements in Simulation of Fire–Wind Interaction and Its Effects on Structures

Fire ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 27
Author(s):  
Maryam Ghodrat ◽  
Farshad Shakeriaski ◽  
David James Nelson ◽  
Albert Simeoni
Keyword(s):  
Slope Angle ◽  
Review Article ◽  
Damage Evaluation ◽  
Safety Engineering ◽  
Fire Damage ◽  
Disturbance Interactions ◽  
Fire Modelling ◽  
Fanning Effect ◽  
The Impact ◽  
Interaction Phenomena

This work provides a detailed overview of existing investigations into the fire–wind interaction phenomena. Specifically, it considers: the fanning effect of wind, wind direction and slope angle, and the impact of wind on fire modelling, and the relevant analysis (numerical and experimental) techniques are evaluated. Recently, the impact of fire on buildings has been widely analysed. Most studies paid attention to fire damage evaluation of structures as well as structure fire safety engineering, while the disturbance interactions that influence structures have been neglected in prior studies and must be analysed in greater detail. In this review article, evidence regarding the fire–wind interaction is discussed. The effect of a fire transitioning from a wildfire to a wildland–urban interface (WUI) is also investigated, with a focus on the impact of the resulting fire–wind phenomenon on high- and low-rise buildings.

Free Vibration Analysis for Thin Wire of Modern Wiresaw Between Sliced Wafers in Wafer Manufacturing Processes

2000 ◽  
Author(s):  
Songbin Wei ◽  
Imin Kao
Keyword(s):  
High Speed ◽  
Free Vibration Analysis ◽  
Equation Of Motion ◽  
Manufacturing Processes ◽  
Thin Wire ◽  
Wire Vibration ◽  
The Wire ◽  
The Impact ◽  
Wafer Manufacturing ◽  
Impact Problem

Abstract In wiresaw manufacturing process where thin wire moving at high speed is pushed onto ingot to produce slices of wafer, the wire is constrained by two wafer walls as it slices into the ingot. In this paper, we investigate the vibration of such wire under the constraints of wafer walls. To address this problem, the model for wire vibration with impact to wafer walls is developed. The equation of motion is discretized using the Galerkin’s method. The principle of impulse and momentum is utilized to solve the impact problem. The results of analysis and simulation indicate that the response under a pointwise sinusoidal excitation is neither periodical nor symmetric with respect to the horizontal axis, due to the excitation from the impact. The wire vibration behavior is affected dramatically by the wafer wall constraints.

scholarly journals Impact of Slope of Growing Trays on Productivity of Wheat Green Fodder by a Nutrient Film Technique System

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3009
Author(s):  
Andrius Grigas ◽  
Aurelija Kemzūraitė ◽  
Dainius Steponavičius ◽  
Aušra Steponavičienė ◽  
Rolandas Domeika
Keyword(s):  
Light Emitting Diode ◽  
Tap Water ◽  
Slope Angle ◽  
Experimental Studies ◽  
Matter Content ◽  
Light Sources ◽  
Dry Matter Content ◽  
Nutrient Film Technique ◽  
Indoor Lighting ◽  
The Impact

Application of hydroponic systems in feed production has not been extensively studied. Therefore, there is insufficient data on the effect of the slope of hydroponic growing trays used in the nutrient film technique on wheat fodder yield and its qualitative parameters. The slope of the trays has only been studied for food crops. This study conducted experimental research using a nutrient film technique hydroponic fodder growing device to evaluate the impact of growing tray slope angle on hydroponic wheat fodder production. The slope angle of the growing trays was changed from 2.0% (1.15°) to 8.0% (4.57°) with increments of 1.5% (0.86°). This research used two different light sources for wheat sprout illumination: indoor lighting (fluorescent lamps) and light-emitting diode illumination. In addition, two nutrient solutions were used for sprout irrigation: tap water and a solution enriched with macro- and microelements. Experimental studies confirmed the hypothesis that the slope angle of growing trays significantly affects the yield of wheat fodder grown for seven days. Analyzing the results, we found that the highest yield of wheat fodder after seven days of cultivation was achieved with growing trays sloped by 6.5% and using indoor lighting. In addition, we achieved the highest wheat fodder dry matter content using a 6.5% slope angle. Experimental studies also confirmed the hypothesis that using macro- and micronutrients in the nutrient solution does not significantly affect the yield of wheat fodder grown hydroponically for seven days.

Adaptive Motion and Force Control of Robots Performing a Complete Task

1999 ◽  
Author(s):  
Prabhakar R. Pagilla ◽  
Biao Yu
Keyword(s):  
Force Control ◽  
Position Control ◽  
Active Phase ◽  
Free Motion ◽  
Constrained Motion ◽  
Control Laws ◽  
Adaptive Motion ◽  
Inactive Phase ◽  
The Impact ◽  
Three Phases

Abstract In this work, we consider adaptive motion and force control of a robot performing a complete task. By a complete task we mean that the robot desired task contains both free motion and constrained motion. Further, we also consider transition from free motion to constrained motion. We divide the motion of the robot into three phases: (i) inactive phase, where the robot is in free motion, (ii) transition phase, where the transition from free motion to constrained motion takes place, and (iii) active phase, where the robot is in constrained motion with simultaneous force and position control. Uncertainty of the constraint results in the impact of robot with the constraint surface when transition from free motion to constrained motion. We design stable control laws for the three phases that results in an efficient algorithm for robots performing a complete task. Extensive experiments are conducted to show the validity of the proposed control designs.

Second Order Sliding Mode Neural Network-Based Visual Servoing of Robot Hands With Fast Manipulation, Including Transition

2005 ◽  
Author(s):  
Rodolfo Garci´a-Rodri´guez ◽  
V. Parra-Vega ◽  
Francisco Rui´z-Sa´nchez
Keyword(s):  
Neural Network ◽  
Visual Servoing ◽  
Sliding Mode ◽  
Second Order ◽  
Constrained Motion ◽  
Unilateral Constraints ◽  
Robot Hands ◽  
Commuting Time ◽  
Algebraic Constraints ◽  
The Impact

Strictly speaking, transition tasks such as those executed by robot hands involve free, impact, and constrained motion regimes, with changing dynamics. Impulsive, unilateral constraints arises in the impact regime, which makes very difficult to design a control system. Moreover, algebraic constraints arise in the constrained regime. The trivial approach would be to avoid impact, and to commute consistently ODE- and DAE-based controller, or to impose virtual constraints to model as a DAE system all regimes. In any case, it is required to know exactly the commuting time. In this paper, a very simple control scheme is proposed based on avoiding impact regime, through zero transition velocity from free to constrained motion, therefore impulsive dynamics does not appear. This is possible because we guarantee exactly the time to commute with a novel well-posed finite time convergence scheme, to produce convergence toward any desired trajectory at any given arbitrarily time and for any initial condition. In this way, ODE and DAE dynamics/controllers commute stably. Inertial and gravitational forces are compensated by a recurrent neural network driven by image-based position and force tracking errors, with a decentralized structure for each robot. The network is tuned on line with a second order force-position sliding modes to finally guarantee exponential tracking.

scholarly journals Estimating the Uplift Bearing Capacity of Belled Piers Adjacent to Sloping Ground by Numerical Modeling Based on Field Tests

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yangchun Han ◽  
Jiulong Cheng ◽  
Weifeng Zheng ◽  
Shijun Ding
Keyword(s):  
Numerical Modeling ◽  
Bearing Capacity ◽  
Attenuation Coefficient ◽  
Slope Angle ◽  
Field Tests ◽  
Embedment Depth ◽  
Sloping Ground ◽  
Foundation Model ◽  
The Difference ◽  
The Impact

In order to evaluate the uplift bearing capacity of belled piers beside slopes, a series of numerical simulations are carried out based on field tests data. First, a number of uplift loading tests of full-scale belled piers are carried out on the project site of transmission line in Anhui Province, China. Second, a slope-foundation model for numerical modeling is proposed and calibrated based on field tests data. The behavior of belled piers adjacent to slopes subject to uplift load is studied by numerical modeling. The impact of three parameters, including distance (a) from the belled pier to the crest of the slope, slope angle (β), and embedment depth (h) of the belled pier, has been investigated on the uplift capacity of the belled pier. Based on the simulation results, an attenuation coefficient (ω) is put forward for evaluating the reduction of uplift bearing capacity of the belled pier. The results show that the coefficient ω is negatively correlated with distance a and depth h, and the influence of distance a is greater than that of depth h according to the results of variance analysis, but the difference is not significant by F test. Moreover, the empirical equation between attenuation coefficient ω and three key factors a, β, and h had been presented by a series of fitting.

scholarly journals Erosion Failure of a Soil Slope by Heavy Rain: Laboratory Investigation and Modified GA Model of Soil Slope Failure

2019 ◽  
Vol 16 (6) ◽  
pp. 1075 ◽  
Author(s):  
Xiaofei Jing ◽  
Yulong Chen ◽  
Changshu Pan ◽  
Tianwei Yin ◽  
Wensong Wang ◽  
...  
Keyword(s):  
Laboratory Investigation ◽  
Slope Failure ◽  
Slope Angle ◽  
Heavy Rain ◽  
Annual Rainfall ◽  
Soil Slope ◽  
Saturated Zone ◽  
Wetting Front ◽  
Rainfall Condition ◽  
The Impact

Rainfall has been identified as one of the main causes for slope failures in areas where high annual rainfall is experienced. The slope angle is important for its stability during rainfall. This paper aimed to determine the impact of the angle of soil slope on the migration of wetting front in rainfall. The results proved that under the same rainfall condition, more runoff was generated with the increase of slope angle, which resulted in more serious erosion of the soil and the ascent of wetting front. A modified Green-Ampt (GA) model of wetting front was also proposed considering the seepage in the saturated zone and the slope angle. These findings will provide insights into the rainfall-induced failure of soil slopes in terms of angle.

scholarly journals Transition from Electromechanical Dynamics to Quasi-Electromechanical Dynamics Caused by Participation of Full Converter-Based Wind Power Generation

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6270
Author(s):  
Jianqiang Luo ◽  
Siqi Bu ◽  
Jiebei Zhu
Keyword(s):  
Power Generation ◽  
Power Systems ◽  
Wind Power ◽  
Oscillation Mode ◽  
Wind Power Generation ◽  
Correlation Ratio ◽  
State Variables ◽  
Interesting Phenomenon ◽  
Electromechanical Dynamics ◽  
The Impact

Previous studies generally consider that the full converter-based wind power generation (FCWG) is a “decoupled” power source from the grid, which hardly participates in electromechanical oscillations. However, it was found recently that strong interaction could be induced which might incur severe resonance incidents in the electromechanical dynamic timescale. In this paper, the participation of FCWG in electromechanical dynamics is extensively investigated, and particularly, an unusual transition of the electromechanical oscillation mode (EOM) is uncovered for the first time. The detailed mathematical models of the open-loop and closed-loop power systems are firstly established, and modal analysis is employed to quantify the FCWG participation in electromechanical dynamics, with two new mode identification criteria, i.e., FCWG dynamics correlation ratio (FDCR) and quasi-electromechanical loop correlation ratio (QELCR). On this basis, the impact of different wind penetration levels and controller parameter settings on the participation of FCWG is investigated. It is revealed that if an FCWG oscillation mode (FOM) has a similar oscillation frequency to the system EOMs, there is a high possibility to induce strong interactions between FCWG dynamics and system electromechanical dynamics of the external power systems. In this circumstance, an interesting phenomenon may occur that an EOM may be dominated by FCWG dynamics, and hence is transformed into a quasi-EOM, which actively involves the participation of FCWG quasi-electromechanical state variables.

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