scholarly journals Kinematics, Dynamics, and Optimal Control of Pneumatic Hexapod Robot

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Long Bai ◽  
Lu-han Ma ◽  
Zhifeng Dong ◽  
Xinsheng Ge
Keyword(s):  
Engineering Application ◽  
Pseudospectral Method ◽  
Hexapod Robot ◽  
Dynamics Modeling ◽  
Rescue Operation ◽  
The Matrix ◽  
Calculation Results ◽  
Practical Engineering ◽  
Body Joints ◽  
Relationship Of

Pneumatic hexapod robot is driven by inert gas carried by itself, which has board application prospect in rescue operation of disaster conditions containing flammable gas. Cruising ability is main constraint for practical engineering application which is influenced by kinematics and dynamics character. The matrix operators and pseudospectral method are used to solve dynamics modeling and numerical calculation problem of robot under straight line walking. Kinematics model is numerically solved and relationship of body, joints, and drive cylinders is obtained. With dynamics model and kinematics boundary conditions, the optimal input gas pressure of leg swing and body moving in one step is obtained by pseudospectral method. According to action character of magnetic valve, calculation results of control inputs satisfy engineering design requirements, and cruising ability under finite gas is obtained.

Synthetic Design of High Aspect Ratio Folding Wings Based on Aeroelastic Analysis

2014 ◽  
Vol 607 ◽  
pp. 409-412
Author(s):  
Sheng Li Lv ◽  
Cheng Wang ◽  
Yang Biao Ou ◽  
Guang Jun Yang ◽  
Xiao Yan Tong
Keyword(s):  
Engineering Application ◽  
Element Model ◽  
Expansion Process ◽  
Sweep Angle ◽  
Flutter Speed ◽  
Aeroelastic Analysis ◽  
Flutter Analysis ◽  
Practical Engineering ◽  
Analysis Models ◽  
Relationship Of

Finite element model of folding wings was designed in the light of structural scheme, and each part of the model used composites. Different aeroelastic analysis models were built from emission to cruise, and then the models were made the study focus on flutter analysis. The result showed the change relationship of the critical flutter speed of wings and flutter frequency with sweep angle in state of expansion process, and the change relationship of the critical flutter speed of wings and flutter frequency of folding wings with cruising altitude and cruise Mach number in state of cruise. The whole flight state was analyzed if the folding wings might flutter, and if it took place the structure optimization of wings was needed. Simulation results have a certain guiding significance for practical engineering application.

Dynamic Characteristics and Stability Analysis of Two-Dimensional (2D) Electro-Hydraulic Proportional Directional Valve

2015 ◽  
Author(s):  
S. Li ◽  
J. Ruan ◽  
B. Meng ◽  
W. A. Jia ◽  
H. Y. Xie
Keyword(s):  
Dynamic Characteristics ◽  
Magnetic Force ◽  
Engineering Application ◽  
Proportional Valve ◽  
Acceptable Range ◽  
Hydrostatic Force ◽  
Practical Engineering ◽  
Direct Operation ◽  
Electrohydraulic Valve ◽  
Proportional Directional Valve

A 2D electrohydraulic proportional directional valve is proposed, which integrates both direct and pilot operation of the valve. In this valve, the output magnetic force of the proportional solenoid is converted to rotate the spool through a thrust-torsion coupling and thus the pressure in the valve sensitive chamber is varied. The varied pressure exerted on the areas of the spool end produces a hydrostatic force to move the spool linearly, which will rotate the spool reversely. Theoretical analysis is carried to the proposed valve and the effects of the key geometric parameters on the dynamic characteristics of the 2D valve and stability are investigated. Experiments are also designed to access to the characteristics of the valve working under direct and pilot operation. The 2D electrohydraulic valve can work properly for both direct operation and pilot operation. The hysteresis and frequency response are measured and the results are within the acceptable range in practical engineering application required of the directional proportional valve.

Load Calculation and Life Prediction for Auto Water Pump Bearing

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Zhengmei Li ◽  
Qiong Zhou ◽  
Jianping Tang ◽  
Jianwen Wang ◽  
Qi An
Keyword(s):  
Load Distribution ◽  
Normal Load ◽  
Analytical Calculation ◽  
Engineering Application ◽  
Water Pump ◽  
Bearing Load ◽  
Calculation Results ◽  
Bearing Design ◽  
Bearing Loads

Taking the water pump bearing with one roller row (WR)-type auto water pump bearing as a research sample, an analytical calculation method is developed to improve the accuracy and efficiency of the current calculations for the bearing loads and life in engineering application. Considering the misalignment due to the deflection of the bearing spindle, the bearing internal loads and deformations under the action of the complicated external space loads are obtained. The bearing fatigue life including the lives of the rollers and the balls is also calculated with considering the non-normal load distribution caused by the spindle deflection and the roller tilt. The bearing load and life calculation results are compared with those calculated by the traditional method in which the deflection of the bearing spindle and the roller tilt are ignored. The effects of the bearing spindle deflection on the load distribution and the life of the auto water pump bearing are analyzed and discussed. The life decrease in the auto water pump bearing is significant due to the deflection of the bearing spindle and it is recommended to give more attention to this deflection for the high quality of the bearing design and calculation.

scholarly journals ADA Solve the Cubic Equation in a New Method with Engineering Application

2020 ◽  
Vol 13 (3) ◽  
pp. 223-231
Author(s):  
Abdullah Dhayea Assi
Keyword(s):  
Classical Method ◽  
Engineering Application ◽  
Cubic Equation ◽  
A Value ◽  
Main Equation ◽  
The Matrix ◽  
Solution Equation ◽  
As Stress ◽  
Initial Root ◽  
Examination Room

         Up to date the cubic equation or matrix tensor is consisting of nine values ​​such as stress tensor that turns into the cubic equation which has been used for solving classic method. This is to impose an initial root several times to get it when achieves the equation and any other party is zero. Then dividing the cubic equation on the equation of the root. After that dividing the cubic equation on the equation of the root and using the classical method to find the rest of the roots. This is a very difficult issue, especially if the roots are secret or large for those who are looking in a difficult field or even for those who are in the examination room. In this research, two equations were reached, one that calculates the angle and the other that calculates the three roots at high accuracy without any significant error rate. By taking advantage of the traditional method, not by imposing a value to get the root of that equation, but by imposing an equation to get the solution equation that gives the value of that root. After imposing that equation, the general equation was derived from which that calculated the three roots directly and without any attempts. The angle that was implicitly derived during the derive of the main equation is calculated by taking advantage of the constants that do not change (invariants) for the matrix tensor (T).

scholarly journals An Analysis of the Retention of a Diamond Particle in a Metallic Matrix after Hot Pressing

2017 ◽  
Vol 17 (1) ◽  
pp. 17-20 ◽  
Author(s):  
J. Borowiecka-Jamrozek ◽  
J. Lachowski
Keyword(s):  
Elastic Energy ◽  
Synthetic Diamond ◽  
Computer Modelling ◽  
Diamond Particle ◽  
Metallic Matrix ◽  
Mechanical Parameters ◽  
Powder Mixtures ◽  
The Matrix ◽  
Calculation Results ◽  
Abaqus Software

Abstract This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the radius of plastic zone around particle.

scholarly journals Experimental Study on Influence of Temperature to Control Performance for Viscoelastic Materials Pounding Tuned Mass Damper

2021 ◽  
Vol 8 ◽  
Author(s):  
Dehui Ye ◽  
Jie Tan ◽  
Yabin Liang ◽  
Qian Feng
Keyword(s):  
Engineering Application ◽  
Tuned Mass Damper ◽  
Frame Structure ◽  
Force Model ◽  
Viscoelastic Materials ◽  
Mass System ◽  
Mass Damper ◽  
Different Temperatures ◽  
Practical Engineering ◽  
Portal Frame Structure

The pounding tuned mass damper (PTMD) is a novel passive damper that absorbs and dissipates energy by an auxiliary tuned spring-mass system. Viscoelastic materials are attached to the interface of the limitation collar in the PTMD so that the energy dissipation capacity can be enhanced. Previous studies have successfully demonstrated the effectiveness of PTMD at room temperature. However, in practice, the PTMD may face a broad temperature range, which can affect the mechanical properties of the viscoelastic materials. Thus, the study of vibration control effectiveness of PTMD at different temperatures is of great significance for its practical engineering application. In this paper, a series of experiments were conducted to investigate the performance of a PTMD in a temperature-controlled environment. A PTMD device was designed to suppress the vibration of a portal frame structure and tested across environmental temperatures ranging from –20°C to 45°C. The displacement reduction ratios demonstrated the temperature robustness of the PTMD. Additionally, the numerical results validated the accuracy of the pounding force model and the performance of PTMD.

scholarly journals Oculomotor activity parameters of the operator in the P300 brain computer interface and similar stimulus situations

2015 ◽  
Vol 8 (4) ◽  
pp. 134-144
Author(s):  
I.A. Basyul
Keyword(s):  
Average Length ◽  
Brain Computer Interface ◽  
Computer Interface ◽  
Similar Stimulus ◽  
The Matrix ◽  
Relationship Of ◽  
The Relationship ◽  
Visual Fixations ◽  
Oculomotor Activity ◽  
Stimulus Environment

Hypotheses about the relationship of the processes of visual perception and variations of the task in an identical stimulus environment was tested. The following tasks were tested: 1) a simple observation of the illuminations of the character in the matrix; 2) counting the number of highlights; 3) monitoring of the target symbol highlights and typing text with the P300 BCI. In a group of 14 people showed that the highest average length of visual fixation and the lowest dispersion of fixation observed for the second type of task. Statistically significant differences in the level of dispersion of visual fixations found between 1-2 and 1-3 modes; differences between the modes for the duration of fixations are at trends. Significant differences in the number of visual fixations on the target symbols wasn’t detected. The overall conclusion is the high perspective of pairing methodology brain-computer interface on the P300 wave with eye tracking to optimize the characteristics of the stimulus in the BCI environment. The differences in the parameters of oculomotor activity between the tasks reflect the level of attention concentration in the target symbols of the P300 BCI

Practical Calculation Method for the Bearing Capacity at High Temperature of Concrete Filled Steel Tubular Columns Subjected to Fire

2014 ◽  
Vol 1065-1069 ◽  
pp. 1358-1362
Author(s):  
Jin Sheng Han ◽  
Hao Ran Liu ◽  
Shu Ping Cong
Keyword(s):  
High Temperature ◽  
Bearing Capacity ◽  
Fire Resistance ◽  
Calculation Method ◽  
Engineering Application ◽  
Practical Calculation ◽  
Tubular Columns ◽  
Calculation Results ◽  
Simplified Calculation ◽  
Simplified Calculation Method

The fire resistance of concrete filled steel tubular column is usually obtained by the numerical analysis method, which is difficult to operate and not convenient in the actual civil engineering. So it is necessary to study the simplified calculation method. A large number of numerical simulation results of the temperature distribution of the section and the bearing capacity at high temperature of the concrete filled steel tubular columns are analyzed. The influences of secondary parameters are simplified. The simplified calculation method at 150 min and 180 min for the bearing capacity at high temperature of concrete filled steel tubular columns subjected to axial compression and fire is presented on the basis of comprehensive analysis of the numerical calculation results. The calculation results can be used as the basis to judge the fire resistance. It is shown by the comparison with the experimental results that the precision of the simplified calculation method can meet the requirements of engineering application.

Study on Flexural Behavior of Pre-Stressed Concrete Hollow Slabs Strengthen with CFRP

2013 ◽  
Vol 446-447 ◽  
pp. 1413-1416
Author(s):  
Bo Wang ◽  
Juan Han
Keyword(s):  
Experimental Method ◽  
Engineering Application ◽  
Flexural Behavior ◽  
Experimental Basis ◽  
Concentrated Force ◽  
Disaster Area ◽  
Practical Engineering ◽  
Symmetrical Load

The purpose of this paper is to focus on studying its flexural behavior after different damages pre-stressed concrete hollow slab is strengthened with CFRP. By the experimental method, twelve residential pre-stressed concrete hollow slabs are tested under concentrated force at the two points of the symmetrical load in order to analyze both flexural behavior and effects factored by different bonding modes. The conclusion can be drawn that the flexural behavior of pre-stressed concrete hollow slabs strengthened with CFRP is well-tried. It provides design suggestions and reference for pre-stressed concrete hollow slabs strengthened with CFRP, and also provides an experimental basis for the repairing and reinforcing practical engineering application in Wenchuan disaster area.

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