scholarly journals Research on folding suspension of multi-constrained rover based on the variation and fusion of rods and pairs

2017 ◽  
Vol 14 (4) ◽  
pp. 172988141772733
Author(s):  
Fei Yang ◽  
Honghao Yue ◽  
Meng Li ◽  
Jianguo Tao ◽  
Zongquan Deng
Keyword(s):  
Mathematical Model ◽  
Graph Theory ◽  
Functional Diversity ◽  
Structural Characteristics ◽  
Engineering Application ◽  
Cost Ratio ◽  
Planetary Rovers ◽  
Limited Space ◽  
Space Launch ◽  
Efficiency Cost

Planetary rovers with folding functions can solve the contradiction between the limited space of the vehicle and the functional diversity of the rover and greatly improve the efficiency–cost ratio of space launch activities. In this article, the multi-constrained quadrilateral suspension is considered based on the practical requirements of planetary detection. Based on graph theory and metamorphic theory, the structural characteristics and movement patterns of the rover are analyzed, the configuration transforming process of adding or decreasing the number of rods and kinematic pairs during folding is studied, and the corresponding mathematical model is established. The suspension of the rover is divided into three basic units, and the folding study is performed around each unit. The folding set of each unit type is given, and a feasible folding set is selected for each type of unit according to their structural characteristics and constraint conditions. At the same time, 15-folding schemes for the rover are given, and the optimal scheme is determined. According to the final folding scheme of the rover, the principle prototype of the rover is developed, and the functional experiment of the folding and unfolding is performed. The experimental results verify the feasibility and rationality of the folding scheme, indicating that the developed detection vehicle has a large fold ratio, which can fully adapt to the limited space inside the rocket. The theoretical and technical results can provide technical support for the engineering application of subsequent rovers with folding.

The Automatic Generation of a Mathematical Model for Machinery Systems

1973 ◽  
Vol 95 (2) ◽  
pp. 629-635 ◽  
Author(s):  
D. A. Smith ◽  
M. A. Chace ◽  
A. C. Rubens
Keyword(s):  
Mathematical Model ◽  
Graph Theory ◽  
Computer Program ◽  
Mechanical System ◽  
Input Data ◽  
Automatic Generation ◽  
Electrical Networks ◽  
Lagrange’S Equation ◽  
Detailed Explanation ◽  
Independent Loops

This paper presents a detailed explanation of a technique for automatically generating a mathematical model for machinery systems. The process starts from a relatively small amount of input data and develops the information required to model a mechanical system with Lagrange’s equation. The technique uses elements of graph theory which were developed for electrical networks. The basic identifications required for mechanical systems are: paths from ground to mass centers, the independent loops of parts, if any, and paths associated with applied force effects. The techniques described in this paper have been used successfully in a generalized computer program, DAMN.

scholarly journals Cryptographic Recursive Control of Integrity of Metadata Electronic Documents. Part 1. Mathematical Model

2020 ◽  
pp. 2-18
Author(s):  
Dmitry Tali ◽  
◽  
Oleg Finko ◽  
◽  
Keyword(s):  
Mathematical Model ◽  
Graph Theory ◽  
Information Systems ◽  
Control Method ◽  
Research Result ◽  
Document Management ◽  
Technical Solution ◽  
Electronic Document ◽  
Electronic Documents ◽  
Electronic Document Management

The purpose of the research is to increase the level of security of electronic document metadata in the face of destructive influences from authorized users (insiders). Research methods: new scientific results allowed using a combination of data integrity control method based on the «write once» method and of authentication of HMAС messages (hash-based message authentication, as well as graph theory methods. Research result: a method of cryptographic recursive 2-D control of the integrity of electronic documents metadata is proposed. The analysis of the object of the study was carried out, based on the results of which it was concluded that it is necessary to effectively protect the metadata of electronic documents processed by automated information systems of electronic document management. Developed and described a mathematical model of the proposed method, based on graph theory. The developed technical solution makes it possible to implement the functions of cryptographic recursive twodimensional control of the integrity of the metadata of electronic documents, as well as to provide the possibility of localizing modified (with signs of violation of integrity) metadata records, in conditions of destructive influences of authorized users (insiders). This, in turn, reduces the likelihood of collusion between trusted parties by introducing mutual control over the results of their actions. The proposed solution makes it possible to ensure control of the integrity of data processed by departmental automated information systems of electronic document management, where, due to the peculiarities of their construction, it is impossible to effectively use the currently popular blockchain technology.

scholarly journals Key Aspects of the Proper Formulation of the Model in Numerical Analysis of the Influence of Mining Exploitation on Buildings

2015 ◽  
Vol 36 (2) ◽  
pp. 17-28
Author(s):  
Lucyna Florkowska ◽  
Jan Walaszczyk
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Numerical Modelling ◽  
Underground Mining ◽  
Structural Characteristics ◽  
Number Of Factors ◽  
Proper Formulation ◽  
Key Aspects ◽  
The Impact ◽  
Complex Matter

Abstract Numerical modelling is an important tool used to analyse various aspects of the impact of underground mining on existing and planned buildings. The interaction between the building and the soil is a complex matter and in many cases a numerical simulation is the only way of making calculations which will take into consideration the co–existence of a number of factors which have a significant influence on the solution. The complexity of the matter also makes it a difficult task to elaborate a proper mathematical model – it requires both a thorough knowledge of geologic conditions of the subsoil and the structural characteristics of the building. This paper discusses the most important problems related to the construction of a mathematical model of a building-mining subsoil system. These problems have been collected on the basis of many years of experience the authors have in observing the surveying and tensometric deformations of the rock–mass and buildings as well as in mathematical and numerical modelling of the observed processes.

scholarly journals Application of Linear and Nonlinear Graphs in Structural Synthesis of Kinematic Chains

1973 ◽  
Vol 95 (2) ◽  
pp. 525-532 ◽  
Author(s):  
M. Huang ◽  
A. H. Soni
Keyword(s):  
Mathematical Model ◽  
Graph Theory ◽  
Structural Analysis ◽  
Three Dimensional ◽  
Structural Synthesis ◽  
Kinematic Chains ◽  
Piston Cylinder ◽  
General Constraints ◽  
Analysis And Synthesis ◽  
Linear And Nonlinear

Using graph theory and Polya’s theory of counting, the present paper performs structural synthesis and analysis of planar and three-dimensional kinematic chains. The Section 2 of the paper develops a mathematical model that permits one to perform structural analysis and synthesis of planar kinematic chains with kinematic elements such as revolute pairs, cam pairs, springs, belt-pulley, piston-cylinder, and gears. The theory developed is applied to enumerate eight-link kinematic chains with these kinematic elements. The Section 3 of the paper develops a mathematical model that permits one to perform structural analysis and synthesis of multi-loop spatial kinematic chains with higher and lower kinematic pairs. The theory developed is applied to enumerate all possible two-loop kinematic chains with or without general constraints.

scholarly journals “Buy Online, Pick Up in Store” under Fit Uncertainty: To Offer or Not to Offer

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Huijing Li ◽  
Shilei Yang ◽  
Haiyan Kang ◽  
Victor Shi
Keyword(s):  
Mathematical Model ◽  
Distribution Function ◽  
Cost Ratio ◽  
Cost Factor ◽  
Optimal Decisions ◽  
Numerical Studies ◽  
Shopping Experience ◽  
Complex Decision ◽  
The Cost ◽  
Decision Complexity

Retailers offer BOPS (Buy Online, Pick Up in Store) service to improve consumers shopping experience. However, this greatly increases the decision complexity for retailers and consumers. For consumers, whether to purchase online or from a store with the BOPS service is a complex decision. This is especially true when the product has fit uncertainty. That is, consumers are uncertain about product fitness before using it. Also, their store visit cost can be heterogeneous and follows some distribution function. For a retailer, it needs to jointly optimize multiple decisions including the convenience degree of BOPS. To help the retailer develop the jointly optimal decisions, we first build a mathematical model where the retailer sells the product through online and store channel and analyzes the possible effects of BOPS. We find that the retailer should offer BOPS when the channel cost ratio (ratio of shipment fee divided by average store visit cost) is large enough. Through numerical studies, we show that the ratio of profit offering BOPS divided by the benchmark increases with the probability of product fit, shipment fee, and the convenience degree of BOPS. We then consider the case where the convenience degree of BOPS is also a decision itself. We find the optimal convenience degree of BOPS increases along with the average store visit cost and the probability of product fit. When the cost factor of offering the convenience for BOPS is larger than a threshold, the retailer should never offer BOPS.

Design of a New Multi-Channel High-Low Pressure Micro-Ejection System

2011 ◽  
Vol 189-193 ◽  
pp. 4313-4317
Author(s):  
Wei Yang ◽  
Qiang Yin ◽  
Kun Wang Niu ◽  
Jiao Zhang ◽  
Wen Dong Zhang
Keyword(s):  
Mathematical Model ◽  
Numerical Analysis ◽  
Structural Design ◽  
Structural Characteristics ◽  
Low Pressure ◽  
Classical Trajectory ◽  
Design Methods ◽  
Analysis And Design ◽  
Bullet Velocity

According to the structural characteristics of the multi-channel high-low pressure micro-ejection system,this paper sets up mathematical model of the trajectory based on the classical trajectory theory,makes numerical analysis to prove the rationality of the structural design,tests the pressure and bullet velocity of the launching system.The results show that the analysis and design methods of the multi-channel high-low pressure micro-ejection system are reasonable and reliable.

Parametric Variational Principle of Viscoplastic Lubrication Model

1992 ◽  
Vol 114 (4) ◽  
pp. 731-735 ◽  
Author(s):  
C. W. Wu ◽  
W. X. Zhong ◽  
L. X. Qian ◽  
L. C. Hu ◽  
S. M. Sun
Keyword(s):  
Mathematical Model ◽  
Mathematical Method ◽  
Variational Principle ◽  
Original Problem ◽  
Engineering Application ◽  
Tangential Velocity ◽  
Control Vector ◽  
Parametric Variational Principle ◽  
Variational Process ◽  
The Mathematical Model

An effective mathematical method to deal with the viscoplastic lubrication model is presented here by applying the parametric variational principle (Zhong, 1985). The plastic slippage of lubricant would occur at the lubricated surfaces under isothermal lubrication. The boundary tangential velocity, therefore, can be taken as the parametric vector (or the control vector) in variational process. The mathematical model of the original problem is finally reduced to a complementarity problem. The algorithm presented in this paper is simple and reliable and shows promise in engineering application.

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