scholarly journals Sensitivity Analysis of the Transmission Chain of a Horizontal Machining Tool Axis to Design and Control Parameters

2014 ◽  
Vol 6 ◽  
pp. 169064 ◽  
Author(s):  
Stefano Mauro ◽  
Stefano Pastorelli ◽  
Tharek Mohtar
Keyword(s):  
Sensitivity Analysis ◽  
Lumped Parameter Model ◽  
Control Parameters ◽  
Damping Coefficients ◽  
Transmission Chain ◽  
Lumped Parameter ◽  
Tool Axis ◽  
Optimal Value ◽  
Structural Parts ◽  
And Control

This paper reports how a numerical controlled machine axis was studied through a lumped parameter model. Firstly, a linear model was derived in order to apply a modal analysis, which estimated the first mechanical frequency of the system as well as its damping coefficients. Subsequently, a nonlinear system was developed by adding friction through experimentation. Results were validated through the comparison with a commercial servoaxis equipped with a Siemens controller. The model was then used to evaluate the effect of the stiffness of the structural parts of the axis on its first natural frequency. It was further used to analyse precision, energy consumption, and axis promptness. Finally a cost function was generated in order to find an optimal value for the main proportional gain of the position loop.

Modeling and Control of a High Pressure Combined Air/Fuel Injection System

2009 ◽  
Author(s):  
Chao Yong ◽  
Eric J. Barth
Keyword(s):  
High Pressure ◽  
Fuel Injection ◽  
Lumped Parameter Model ◽  
Injection System ◽  
Fuel Injection System ◽  
Modeling And Control ◽  
Lumped Parameter ◽  
Mass Flow Rates ◽  
And Control ◽  
Liquid Piston

A high pressure combined air-fuel injection system is designed and tested for an experimental free liquid-piston engine compressor. The application discussed utilizes available high pressure air from the compressor’s reservoir, and high pressure fuel to mix and then inject into a combustion chamber. This paper addresses the modeling, design and control for this particular high-pressure air-fuel injection system, which features an electronically controlled air/fuel ratio control scheme. This system consists of a fuel line and an air line, whose mass flow rates are restricted by metering valves. These two lines are connected to a common downstream tube where air and fuel are mixed. By controlling the upstream pressures and the orifice areas of the metering valves, desired A/F ratios can be achieved. The effectiveness of the proposed system is demonstrated by a lumped-parameter model in simulation and validated by experiments.

Optimization of Equipment Control Parameters to Minimize HVAC Energy Consumption

2011 ◽  
Author(s):  
Aaron P. Wemhoff
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Control Method ◽  
The United States ◽  
Lumped Parameter Model ◽  
Base Case ◽  
Control Parameters ◽  
Household Energy ◽  
Lumped Parameter ◽  
Air Conditioning Systems

Heating, Ventilating, and Air Conditioning Systems (HVAC) consume nearly one-third of household energy in the United States. The optimization of the control parameters in HVAC equipment allows for a reduction in energy consumption. In this study, a supervisory control method is applied to a lumped parameter model of an HVAC system of interest containing a chiller and three dampers. The method determines the choice of control parameters that minimize the energy consumption for 1000 sampled steady-state loads. An energy savings of 39% was achieved using the method in this study compared to the base case.

Parameter Sensitivity Analysis of a Lumped-Parameter Model of Lymphangions in Series

2012 ◽  
Author(s):  
Samira Jamalian ◽  
James E. Moore ◽  
Christopher D. Bertram ◽  
Will Richardson
Keyword(s):  
Sensitivity Analysis ◽  
Interstitial Fluid ◽  
Lymphatic System ◽  
Lumped Parameter Model ◽  
Node Dissection ◽  
Parameter Sensitivity Analysis ◽  
Protein Balance ◽  
Vital Functions ◽  
Lumped Parameter ◽  
In Series

The lymphatic system is responsible for vital functions in the human body. In particular, it plays an important role in the immune system mechanism whereby undesirable elements are destroyed in the lymph nodes. But cancer cells also spread via the lymphatic system. The system maintains fluid and protein balance by gathering approximately 4 L/day of interstitial fluid and returning it to the venous system. Lymphedema, an ailment of the system for which there is no known cure, primarily affects cancer patients who have undergone lymph node dissection [1]. To understand how to treat such pathologies of the lymphatic system, it is first necessary to examine its fluid flow and pumping mechanisms quantitatively.

scholarly journals Parameter sensitivity analysis of a lumped-parameter model of a chain of lymphangions in series

2013 ◽  
Vol 305 (12) ◽  
pp. H1709-H1717 ◽  
Author(s):  
Samira Jamalian ◽  
Christopher D. Bertram ◽  
William J. Richardson ◽  
James E. Moore
Keyword(s):  
Sensitivity Analysis ◽  
Flow Rate ◽  
Pressure Difference ◽  
Lymphatic System ◽  
Lumped Parameter Model ◽  
Average Flow Rate ◽  
Average Flow ◽  
Lumped Parameter ◽  
Time Average ◽  
A Chain

Any disruption of the lymphatic system due to trauma or injury can lead to edema. There is no effective cure for lymphedema, partly because predictive knowledge of lymphatic system reactions to interventions is lacking. A well-developed model of the system could greatly improve our understanding of its function. Lymphangions, defined as the vessel segment between two valves, are the individual pumping units. Based on our previous lumped-parameter model of a chain of lymphangions, this study aimed to identify the parameters that affect the system output the most using a sensitivity analysis. The system was highly sensitive to minimum valve resistance, such that variations in this parameter caused an order-of-magnitude change in time-average flow rate for certain values of imposed pressure difference. Average flow rate doubled when contraction frequency was increased within its physiological range. Optimum lymphangion length was found to be some 13–14.5 diameters. A peak of time-average flow rate occurred when transmural pressure was such that the pressure-diameter loop for active contractions was centered near maximum passive vessel compliance. Increasing the number of lymphangions in the chain improved the pumping in the presence of larger adverse pressure differences. For a given pressure difference, the optimal number of lymphangions increased with the total vessel length. These results indicate that further experiments to estimate valve resistance more accurately are necessary. The existence of an optimal value of transmural pressure may provide additional guidelines for increasing pumping in areas affected by edema.

Design, Analysis, Experimentation, and Control of a Partially Compliant Bistable Mechanism

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Ayse Tekes ◽  
Hongkuan Lin ◽  
Kevin McFall
Keyword(s):  
Dynamic Response ◽  
Elliptic Integral ◽  
Three Dimensional ◽  
Design Analysis ◽  
Lumped Parameter Model ◽  
Lumped Parameter ◽  
Rigid Body Model ◽  
3D Printed ◽  
Bistable Mechanism ◽  
And Control

Abstract This study presents the design analysis and development of a novel partially compliant bistable mechanism. Motion behavior dependence on links and relative angles are analyzed, lumped parameter model is derived, mechanism parts including the compliant members are three-dimensional (3D) printed and a state feedback controller is implemented so that the slider follows a well-defined trajectory if designed as an actuator. The proposed mechanism consists of initially straight, large deflecting fixed-pinned compliant links, rigid links, and a sliding mass. Dynamic response of the mechanism is studied using elliptic integral solutions, pseudo rigid body model (PRBM), vector closure loop equations and Elliptic integrals. Nonlinear model is simulated in matlab simulink using fourth‐order Runge‐Kutta algorithms. The research emphasizes on the realization and dynamic response of the mechanism and the trajectory control of the slider so that the slider can be kept constant at specified distances resulting a dwell motion if designed as a linear actuator.

Three Formulations of Sling Load Dynamics for UAV Motion Planning and Control

2018 ◽  
Author(s):  
Alexander Cicchino ◽  
Inna Sharf
Keyword(s):  
Elastic Properties ◽  
Computational Cost ◽  
Solution Space ◽  
Linear Complementarity ◽  
Lumped Parameter Model ◽  
Complementarity Conditions ◽  
Planning And Control ◽  
Lumped Parameter ◽  
Aerial Vehicle ◽  
And Control

In this paper, the sling load dynamics of an aerial vehicle carrying a payload are investigated by employing three formulations of the governing equations. They are the hybrid formulation where the system exists in either a taut cable or slack cable configuration, with appropriate treatment of the transition between the two; the linear complementarity problem (LCP) formulation where the cable constraints are imposed as linear complementarity conditions and finally, the lumped parameter formulation where the cable is modelled with a series of spring-mass elements. The hybrid and LCP formulations neglect the elasticity of the cable while the lumped parameter model explicitly accounts for the elastic properties of the cable, albeit in a discrete way. The importance of the incorporation of elastic properties of the cable on the system is investigated for the variation in solution space of the payload. The three formulations are compared numerically, for information on the computational cost, motion of the payload, and tension profile, for several aerial maneuvers, including an aggressive obstacle avoidance with a window clearance flight.

Lumped Parameter Model of Planetary Gear Systems

1978 ◽  
Vol 192 (1) ◽  
pp. 251-258 ◽  
Author(s):  
J. W. Polder
Keyword(s):  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Lumped Parameter Model ◽  
Damping Coefficients ◽  
Planetary Gear Trains ◽  
Lumped Parameter ◽  
Vibration Model ◽  
Close Relationship ◽  
Angular Velocities ◽  
Gear Trains

A model system is described by parameters for shafts, planetary gear trains and nodes. Moments of inertia, spring stiffnesses and damping coefficients are assigned to the shafts; gear ratios and efficiencies are assigned to planetary gear trains. The equivalence of angular velocities and torques is demonstrated for shafts (vibration model), as well as for planetary gear trains and nodes (configuration of the system). This brings about a new view on the concept of degrees of freedom. The close relationship between gear ratios and torque ratios yields identical functions for these ratios when applied to the input and output shafts of a system. The full use of this relationship requires strict conventions of signs and an extension of the interpretation of values. The introduction of a new concept, named responsivity, expresses the relationships between torques and between powers of arbitrary shafts. With suitable equations, it becomes possible to investigate torque and power distributions exhaustively.

scholarly journals Lumped parameter model and experimental tests on a pressure limiter for variable displacement pumps

2020 ◽  
Vol 197 ◽  
pp. 07005
Author(s):  
Paola Fresia ◽  
Massimo Rundo
Keyword(s):  
Experimental Tests ◽  
Control Flow ◽  
Lumped Parameter Model ◽  
Load Sensing ◽  
Axial Piston Pumps ◽  
Discharge Coefficients ◽  
Lumped Parameter ◽  
Variable Displacement ◽  
Flow Through ◽  
And Control

The paper presents the lumped parameter model of a pressure limiter for axial piston pumps developed in the Simcenter Amesim® environment. The control includes both the absolute and differential (load sensing) pressure limiter in a single body. The continuous position valve was tested experimentally alone on a test rig in order to estimate the discharge coefficients required for tuning the model. The tests were performed at imposed positions of the spool and the corresponding modulated pressure and control flow through the valve were measured. A contactless transducer was used for measuring with a very high accuracy the spool position. The influence of the bleed orifice on the pressure gain was also measured experimentally. It was found that the discharge coefficients have a significant influence on the hydraulic characteristic of the valve with also a consequence on the dynamic behavior of the entire displacement control.

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