Influencing Factors on Stick-Slip Behavior of a Ball Screw Driven Elevation Mechanism for MLRS

2012 ◽  
Vol 271-272 ◽  
pp. 958-968
Author(s):  
Young Hyu Choi ◽  
Sung Hyun Jang ◽  
Ji Han Oh
Keyword(s):  
Mathematical Model ◽  
Ball Screw ◽  
Force Model ◽  
Stick Slip ◽  
Single Degree Of Freedom ◽  
Stribeck Effect ◽  
The Stability ◽  
Friction Parameters ◽  
The Mathematical Model ◽  
Rocket System

As an MLRS (Multiple Launch Rocket System) cage is moved with a uniform speed through an elevation mechanism for MRLS operated using ball screws, its stick-slip behavior can be observed by the friction in a ball screw actuator. In this study, a single-degree of freedom mathematical model of an MLRS elevation system is designed and its stick-slip behavior is analyzed using a friction force model considering the Stribeck effect. The stability of a vibration system is analyzed through deriving an equation of normalized motion for the mathematical model and the influences of mechanical parameters and friction parameters on the vibration response and stability are theoretically analyzed.

scholarly journals NECESSITY TO IMPROVE THE MATHEMATICAL MODEL OF FREIGHT CARS TO STUDY CASES OF ITS DERAILMENTS

2020 ◽  
pp. 442-451
Author(s):  
А.V. Batig ◽  
A. Ya. Kuzyshyn
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Computer Experiment ◽  
Rolling Stock ◽  
Software Systems ◽  
Freight Car ◽  
The Stability ◽  
The Many ◽  
The Impact ◽  
The Mathematical Model

One of the most important problems that pose a serious threat to the functioning of railways is the problem of freight cars derailment. However, according to statistics, the number of cases of the derailments of freight cars in trains annually grows. Тo prevent such cases, the necessary preventive measures are developed, and to study the causes of their occurrence, a significant number of mathematical models, programs and software systems created by leading domestic and foreign scientists. Studies of such mathematical models by the authors of this work have led to the conclusion that they are not sufficiently detailed to the extent that it is necessary for analyze the reasons of its derailment. At the same time, an analysis of the causes of the rolling stock derailments on the railways of Ukraine over the past five years showed that in about 20 % of cases they are obvious, and in 7 % of cases they are not obvious and implicitly expressed. The study of such cases of rolling stock derailment during an official investigation by the railway and during forensic railway transport expertises requires the use of an improved mathematical model of a freight car, which would allow a quantitative assessment of the impact of its parameters and rail track on the conditions of railway accidents. Therefore, taking into account the main reasons that caused the occurrence of such railroad accidents over the last five years on the railways of Ukraine, the article selected the main directions for improving the mathematical model of a freight car, allowing to cover all the many factors (explicit and hidden) and identify the most significant ones regarding the circumstances of the derailment rolling stock off the track, established on the basis of a computer experiment. It is proposed in the mathematical model of a freight car to take into account the guiding force, the value of which is one of the main indicators of the stability of the rolling stock. The authors of the article noted that not taking into account the influence of the guiding forces on the dynamics of the freight car can lead to an erroneous determination of the reasons for the rolling stock derailment or even to the impossibility of establishing them.

Walking Stability Analysis of Multi-Legged Crablike Robot over Slope

2013 ◽  
Vol 572 ◽  
pp. 636-639
Author(s):  
Xi Chen ◽  
Gang Wang
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Stability Criterion ◽  
Stability Margin ◽  
Static Stability ◽  
Matlab Simulation ◽  
And Performance ◽  
The Stability ◽  
The Mathematical Model ◽  
The Relationship

This paper deals with the walking stability analysis of a multi-legged crablike robot over slope using normalized energy stability margin (NESM) method in order to develop a common stabilization description method and achieve robust locomotion for the robot over rough terrains. The robot is simplified with its static stability being described by NESM. The mathematical model of static stability margin is built so as to carry out the simulation of walking stability over slope for the crablike robot that walks in double tetrapod gait. As a consequence, the relationship between stability margin and the height of the robots centroid, as well as its inclination relative to the ground is calculated by the stability criterion. The success and performance of the stability criterion proposed is verified through MATLAB simulation and real-world experiments using multi-legged crablike robot.

On A Formulation of the Elastic Stability Equations of Circular Cylindrical Shells Under Variable Internal Pressure

1985 ◽  
Vol 9 (2) ◽  
pp. 64-69
Author(s):  
J.L. Urrutia-Galicia ◽  
A.N. Sherbourne
Keyword(s):  
Mathematical Model ◽  
Internal Pressure ◽  
Cylindrical Shells ◽  
Direct Analysis ◽  
Elastic Stability ◽  
Equilibrium Path ◽  
Circular Cylindrical Shells ◽  
The Stability ◽  
Variable Internal Pressure ◽  
The Mathematical Model

The mathematical model of the stability analysis of circular cylindrical shells under arbitrary internal pressure is presented. The paper consists of a direct analysis of the equilibrium modes in the neighbourhood of the unperturbed principal equilibrium path. The final stability condition results in a completely symmetric differential operator which is then compared with current theories found in the literature.

scholarly journals An Approach for the Global Stability of Mathematical Model of an Infectious Disease

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1778
Author(s):  
Mojtaba Masoumnezhad ◽  
Maziar Rajabi ◽  
Amirahmad Chapnevis ◽  
Aleksei Dorofeev ◽  
Stanford Shateyi ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Mathematical Model ◽  
Global Stability ◽  
Incidence Rates ◽  
Endemic Equilibrium ◽  
Symmetry Properties ◽  
Nonlinear Incidence Rates ◽  
Lyapunov Matrix ◽  
The Stability ◽  
The Mathematical Model

The global stability analysis for the mathematical model of an infectious disease is discussed here. The endemic equilibrium is shown to be globally stable by using a modification of the Volterra–Lyapunov matrix method. The basis of the method is the combination of Lyapunov functions and the Volterra–Lyapunov matrices. By reducing the dimensions of the matrices and under some conditions, we can easily show the global stability of the endemic equilibrium. To prove the stability based on Volterra–Lyapunov matrices, we use matrices with the symmetry properties (symmetric positive definite). The results developed in this paper can be applied in more complex systems with nonlinear incidence rates. Numerical simulations are presented to illustrate the analytical results.

Oblique stability of circularly polarized MHD waves

1990 ◽  
Vol 43 (2) ◽  
pp. 257-268 ◽  
Author(s):  
E. Mjølhus ◽  
T. Hada
Keyword(s):  
Mathematical Model ◽  
Finite Amplitude ◽  
Mhd Waves ◽  
Circularly Polarized ◽  
Right Hand ◽  
Wave Trains ◽  
The Stability ◽  
The Right ◽  
The Mathematical Model ◽  
Dnls Equation

The stability of finite-amplitude weakly dispersive circularly polarized MHD wave trains with respect to oblique modulations is investigated. The mathematical model is a multi-dimensional extension of the DNLS equation. We have found that the right-hand-polarized wave, which is stable with respect to parallel modulations, is unstable with respect to certain oblique modulations for most primary wavenumbers.

Performance Simulation and Analysis of the Progressive Distributor of the Oil-Air Lubrication by AMEsim

2013 ◽  
Vol 395-396 ◽  
pp. 1227-1232
Author(s):  
Qi Guo Sun ◽  
A Li Cai ◽  
Hong Bo Lv ◽  
Zheng Hui Zhou
Keyword(s):  
Mathematical Model ◽  
Friction Coefficient ◽  
Viscous Friction ◽  
Simulation Method ◽  
Analytic Method ◽  
Performance Simulation ◽  
Air Lubrication ◽  
Oil Flow ◽  
The Stability ◽  
The Mathematical Model

The mathematical model and the simulation model of the progressive distributor are established using an analytic method and AMEsim, a kind of simulation platform, respectively in this paper. The influences of the progressive structure, the viscous friction coefficient, the flow and pressure of the system and the size of throttle orifice on the performance of the progressive distributor are analyzed by the numerical simulation method. The results show that the fluctuations of the flow and pressure of the system are produced due to the overlapping motion of the three pistons, the oil-flow of the progressive distributor can be stabilized by choosing a reasonable viscous friction coefficient, and motion stability of the pistons of the progressive distributor, and the stability of the flow and pressure for the system are influenced by the size of throttle orifice. These conclusions will provide bases for the design of the oil-air lubricating system and the improvement of the structure of the progressive distributor.

Modeling and Stability Analysis of Hydraulic System for Wave Simulation

2013 ◽  
Vol 291-294 ◽  
pp. 1934-1939
Author(s):  
Jian Jun Peng ◽  
Yan Jun Liu ◽  
Yu Li ◽  
Ji Bin Liu
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Mathematical Models ◽  
Hydraulic System ◽  
Simulation System ◽  
Displacement Sensor ◽  
Schematic Diagram ◽  
Wave Simulation ◽  
The Stability ◽  
The Mathematical Model

This thesis put forward a hydraulic wave simulation system based on valve-controlled cylinder hydraulic system, which simulated wave movement on the land. The mathematical model of valve-controlled symmetric cylinder was deduced and the mathematical models of servo valve, displacement sensor and servo amplifier were established according to the schematic diagram of the hydraulic system designed, on the basis of which the mathematical model of hydraulic wave simulation system was obtained. Then the stability of the system was analyzed. The results indicated that the system was reliable.

Stability of Velocity-Loop-Based Hydraulic Control Loading System

2012 ◽  
Vol 619 ◽  
pp. 472-475
Author(s):  
Pan Guo Qi ◽  
Li Wei Zhao ◽  
Pei Chao Cong ◽  
Hui Wang
Keyword(s):  
Mathematical Model ◽  
Block Diagram ◽  
System Model ◽  
Flight Simulator ◽  
Stability Conditions ◽  
Hydraulic Control ◽  
Function Block ◽  
Loading System ◽  
The Stability ◽  
The Mathematical Model

A hydraulic Control Loading System (CLS) based on velocity-loop was developed and installed on our flight simulator earlier days, but the CLS cannot keep stable in some conditions. This problem is discussed in this paper. The mathematical model of velocity-loop-based CLS is firstly developed with the method of transfer function block diagram. Then, system’s stability conditions are put forward using Roth criterion based on the system model developed. At last, the experiments proves the stability

Performance Calculation of Mill Hydraulic Loading System

2012 ◽  
Vol 479-481 ◽  
pp. 2416-2419
Author(s):  
Xiao Bin Ji ◽  
Xue Yi Qi ◽  
Yong He Feng ◽  
Yang Zhang
Keyword(s):  
Mathematical Model ◽  
Initial Pressure ◽  
Economical Efficiency ◽  
Hydraulic Loading ◽  
Loading System ◽  
The Stability ◽  
The Mathematical Model ◽  
Performance Calculation

The paper research the mathematical model and the stability of the mill hydraulic loading system by analyzing the principle of mill hydraulic loading system, and find that the main reason for unstability is the low initial pressure of the accumulator, and solved basically the unstability problems of the system and improved the safety and the economical efficiency of anlage fahren through the analysis and the adjustment on initial pressure of the accumulator.

scholarly journals Simulation Analysis of One Degree of Freedom Motion of Electromagnetic Spherical Joint based on Maxwell

2021 ◽  
Vol 2085 (1) ◽  
pp. 012014
Author(s):  
Haoran Wang ◽  
Fucong Liu ◽  
Sai Lou
Keyword(s):  
Mathematical Model ◽  
Simulation Analysis ◽  
Lagrange Equation ◽  
Degree Of Freedom ◽  
Spherical Joint ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Structure And Motion ◽  
The Mathematical Model ◽  
The Relationship

Abstract In order to improve the stiffness of the spherical joint of the robot, reduce the difficulty of manufacturing and the complexity of the control system, this paper proposed a method of spherical joint and digital drive of the robot based on the electromagnetic principle. Firstly, introduces the structure and motion principle of the spherical joint of the robot, establishes the mathematical model of the spherical joint and establishes the dynamic model according to the second Lagrange equation. after that, the relationship between the number of ampire-turns of the electromagnet on the spherical joint, the attitude Angle of the rotor and the force of the rotor was obtained by simulating the single degree of freedom of the joint based on Ansys maxwell and Matlab, which provided a basis for the realization of the digital drive of the spherical joint.

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