A mathematical model for a rolling legged robot that uses a shifting center of gravity

2016 ◽  
Author(s):  
Rilwan Mohammed Tukur ◽  
N. Karthikeyan
Keyword(s):  
Mathematical Model ◽  
Center Of Gravity ◽  
Legged Robot

scholarly journals Launch Bar Dynamics Character Analysis of Carrier-Based Aircraft Catapult Launch

2019 ◽  
Vol 9 (15) ◽  
pp. 3079
Author(s):  
Zhu ◽  
Lu ◽  
Yang ◽  
Ji ◽  
Han ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Working Condition ◽  
Center Of Gravity ◽  
Obvious Effect ◽  
Character Analysis ◽  
Driving Mechanisms ◽  
Study Results ◽  
Flight Deck

The launch bar is a unique device of carrier-based aircraft, which is connected to the nose gear and shuttle. In order to avoid the launch bar striking the flight deck after the launch bar pops out of the shuttle, it is very important to research the dynamics performance of the launch bar. This paper establishes a staged mathematical model of catapult launch including the launch bar, a steam-powered catapult, a holdback bar, and a carrier-based aircraft. This article studied the effect of the mass of the launch bar, restoring moment of the launch bar, and center of gravity position of the launch bar on the dynamics performance of the launch bar. The results showed the following: (1) we could reduce the risk collision of the launch bar and deck by reducing the mass of the launch bar, increasing the restoring moment, and shifting the center of gravity position of the launch bar; (2) under the working condition of this article, we changed the center of gravity position of the launch bar to control the sink of the launch bar end, having the most obvious effect, and we reduced the mass of the launch bar, having the least effect on controlling the sink of the launch bar end; however, reducing the mass of the launch bar could also greatly reduce the risk collision of the launch bar and deck; (3) in order to avoid the launch bar striking the flight deck, the restoring moment of the launch bar must overcome the sum of other moments. The study results can give a theoretical reference for designing and testing the launch bars of carrier-based aircraft. It can also give a theoretical reference for designing and testing the launch bar’s driving mechanisms.

scholarly journals Introducing a particular mathematical model for predicting the resistance and performance of prismatic planing hulls in calm water by means of total pressure distribution

2015 ◽  
Vol 12 (2) ◽  
pp. 73-94 ◽  
Author(s):  
P. Ghadimi ◽  
S. Tavakoli ◽  
M. A. Feizi Chekab ◽  
A. Dashtimanesh
Keyword(s):  
Mathematical Model ◽  
Pressure Distribution ◽  
Total Pressure ◽  
Center Of Gravity ◽  
Governing Equations ◽  
Calm Water ◽  
Hydrodynamic Study ◽  
Pass Through ◽  
And Performance

Mathematical modeling of planing hulls and determination of their characteristics are the most important subjects in hydrodynamic study of planing vessels. In this paper, a new mathematical model has been developed based on pressure distribution. This model has been provided for two different situations: (1) for a situation in which all forces pass through the center of gravity and (2) for a situation in which forces don not necessarily pass through the center of gravity. Two algorithms have been designed for the governing equations. Computational results have been presented in the form of trim angle, total pressure, hydrodynamic and hydrostatic lift coefficients, spray apex and total resistance which includes frictional, spray and induced resistances. Accuracy of the model has been verified by comparing the numerical findings against the results of Savitsky's method and available experimental data. Good accuracy is displayed. Furthermore, effects of deadrise angle on trim angle of the craft, position of spray apex and resistance have been investigated.

403 A Multi-legged Robot Considering Efficiency of Center-of-gravity Movement

2006 ◽  
Vol 2006.41 (0) ◽  
pp. 153-154
Author(s):  
Koya TAKAHASHI ◽  
Yoshihiro HAGIHARA ◽  
Takeshi HARAKO ◽  
Yukari HAGIHARA ◽  
Akira HASHIMOTO ◽  
...  
Keyword(s):  
Center Of Gravity ◽  
Legged Robot

scholarly journals Method for determining the spatial position of the center of gravity of machines

2019 ◽  
pp. 71-82
Author(s):  
I. A. Blinov
Keyword(s):  
Mathematical Model ◽  
Computer Model ◽  
Center Of Gravity ◽  
Spatial Position ◽  
Coordinate Method ◽  
The Core ◽  
Measurement Results ◽  
Minimum Number ◽  
Mathematical Processing ◽  
Processing Of Measurement Results

Having analyzed traditional methods for determining the coordinates of the center of gravity of machines, we developed a three-coordinate method using the simplest and most affordable means of hanging products with a crane beam. The method differs from analogues in the minimum number of weighings when there are no force-measuring means as a component of the measuring circuit. We introduce a mathematical model, which is the core of the method, and a computer model which minimizes the complexity of mathematical processing of measurement results

scholarly journals Transport category airplane flight range calculation accounting center-of-gravity position shift and engine throttling characteristics

2021 ◽  
pp. 4-14
Author(s):  
Ruslan Tsukanov ◽  
Viktor Riabkov
Keyword(s):  
Mathematical Model ◽  
Fuel Consumption ◽  
Program Implementation ◽  
Fuel Efficiency ◽  
Real Data ◽  
Center Of Gravity ◽  
Specific Fuel Consumption ◽  
Flight Range ◽  
Position Shift ◽  
Range Calculation

A problem facing world commercial aviation is a provision of the flight range and an increase in the fuel efficiency of transport category airplanes using fuel trim transfer application, which allows for decreasing airplane trim drag at cruise flight. In the existing mathematical models, center-of-gravity position is usually assumed fixed, but with fuel usage, center-of-gravity shifts within the definite range of center-of-gravity positions. Until the fuel trim transfer was not used in airplanes, the center-of-gravity shift range was rather short, that allowed to use the specified assumption without any considerable mistakes. In case of fuel trim transfer use, center-of-gravity shifts can reach 15…20 % of mean aerodynamic chord, that requires considering the center-of-gravity actual position during the flight range calculation. Early made estimated calculations showed the necessity of following mathematical model improvement using accounting the real engine throttling characteristics. The goal of this publication is to develop a method of flight range calculation taking transport category airplane into account actual center-of-gravity position with fuel using and variation in engine-specific fuel consumption according to their throttling characteristics. On the basis of real data from engine maintenance manuals, formulas are obtained for approximation throttling characteristics of turbofan engines in the form of dimensionless specific fuel consumption (related to the specific fuel consumption at full thrust) dependence on the engine throttling coefficient. A mathematical model (algorithm and its program implementation using С language in Power Unit 11.7 R03 system) has been developed to calculate the airplane flight range accounting its actual center-of-gravity position shift with fuel usage and variation in specific fuel consumption according to engine throttling characteristics. Using comparison with known payload-range diagram, adequacy of developed mathematical model is shown. Recommendations to improve the mathematical model are also given.

The Research on Grounding Pressure Distribution of Tracked Travelling Mechanism

2014 ◽  
Vol 526 ◽  
pp. 115-120
Author(s):  
Xi Yang Liu ◽  
Zhi Yong Jiao ◽  
Mei Yu Zhang
Keyword(s):  
Mathematical Model ◽  
Pressure Distribution ◽  
Center Of Gravity ◽  
Core Region ◽  
Tracked Vehicles ◽  
Overall Design ◽  
Ground Pressure ◽  
Ground Conditions ◽  
The Mathematical Model

The grounding pressure of tracked vehicles is closely related to the overall structure of the vehicles and the ground conditions, and its distribution is more complex and changes in the different center of gravity. So in this paper, under certain assumptions, we derive the mathematical model of the grounding pressure distribution through analysis and research, which can predict the ground pressure distribution of tracked vehicles at any moment. By analyzing the tracked grounding pressure distribution, we put forward the concept of core region of track connecting with the ground, and some meaningful conclusions and formulas for the overall design of tracked vehicles.

scholarly journals IMPROVING THE STABILITY TWO-LEVEL CAR HAULER

2017 ◽  
Vol 1 (48) ◽  
pp. 8-18
Author(s):  
N. N. Shpilka
Keyword(s):  
Mathematical Model ◽  
Elastic Properties ◽  
Correct Choice ◽  
Center Of Gravity ◽  
Dynamic Processes ◽  
Lateral Stability ◽  
Location Parameters ◽  
Simulation Results ◽  
The Stability

To improve the lateral stability of car hauler way you value optimal cargo location parameters, elastically mounted on a platform, developed a mathematical model of its motion. At the same time take into account fluctuations in cargo and car hauler. According to the simulation results revealed that the system for car «hauler – cargo» accounting for elastic properties leads to a significant decrease in the frequency and amplitude of the system vertical oscillations. Therefore, the presence of the cargo can be regarded as a dynamic passive damping (in the case of a correct choice and design of layout parameters). There is proposed to reduce the distance between the cargo and the upper platform by determination of maximum values of the cargo oscillations amplitudes. In turn, the reduction of the height of the platform reduces the height of the center of gravity of the system, improves the stability of car hauler. Keywords: car hauler, dynamic processes, fluctuations, platform, stability.  

Hydro-aerodynamic mathematical model and multi-objective optimization of wing-in-ground effect craft in take-off

2017 ◽  
Vol 232 (4) ◽  
pp. 421-433 ◽  
Author(s):  
Mohammad Tavakoli Dakhrabadi ◽  
Mohammad Saeed Seif
Keyword(s):  
Mathematical Model ◽  
High Speed ◽  
Ground Effect ◽  
Practical Method ◽  
Aerodynamic Characteristics ◽  
Center Of Gravity ◽  
Computational Time ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Wing In Ground Effect

Hydro-aerodynamic mathematical model and multi-objective optimization of a popular wing-in-ground effect craft are presented in this research using a hydro-aerodynamic practical method and the genetic algorithm. The primary components of the wing-in-ground effect craft configuration include a compound wing, catamaran hull form and a power-augmented ram platform. The hydro-aerodynamic practical method with low computational time and high accuracy is performed by coupling hydrodynamic and aerodynamic considerations using the potential flow theory in ground effect and the semi-empirical equations proposed for high-speed marine vehicles. The trade-off between hydrodynamic and aerodynamic characteristics makes it difficult to simultaneously satisfy the design requirements of high hydro-aerodynamic performance. In this article, three goals—reduced hump resistance, increased compound wing lift-to-drag ratio and reduced take-off speed—are selected as the objective functions. The longitudinal position of center of gravity, position of outer wing with respect to main wing, power augmented ram platform angle to horizontal and flap angle are also adopted as design variables. Static height stability and the location of the center of gravity with respect to the aerodynamics centers are considered as constraints for the stable flight in ground effect. The optimal solutions of the multi-objective optimization were not unique, rather a set of non-dominated optima, called the Pareto sets, are obtained. As a result of the multi-objective optimization, 25 Pareto individuals are obtained that the naval architects can use in designing wing-in-ground crafts.

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