Applied Mechanics and Materials Vol. 454

Abstract: In recent years, industry and commerce have been developed and economic conditions have been improved, technology evolvement enhances the standard of living. Medical, hygiene, health and welfare issues have drawn public attention. The elderly population to the total population ratio has been increased year by year. Electric wheelchairs or electric scooters have become very important mobile aids for those physically disabled, the elderly, and chronically ill patients everyday lives. Currently the function of wheelchairs on the market is still considerably limited. Most patients are still suffering psychological burden of the shifting of the center of gravity due to uphill, downhill or driving on non-horizontal surface. This study shows how to solve the problem of seat tilt problem while encounter stairs, ramps and other non-horizontal surface. Therefore their insecurity can be reduced and their comfort can be increased. In this study, we constructed a seat with automatically level adjustable seat cushion. By continuously detecting the seat level degree, the tilt angle was detected when driving on non-horizontal surface. Using microcontroller and stepper motors with automatic feedback to adjust the seat to reach the level of the body. By way of this machinery automation can improve the mechanical properties of the seat. This framework will not only improve the existing wheelchair uncomfortable problems, and can also be applied to other moving vehicles.

Abstract: Based on the probability distributions of wind direction and wave direction, the fatigue load is applied to the offshore wind turbine structure according to the actual environmental loading direction. The deterministic fatigue damage due to the wind load and the spectrum fatigue damage due to the wave load are calculated, respectively. Then, the total fatigue damage of the offshore wind turbine structure is obtained by the linear superposition. Compared with the results that the fatigue damage of the offshore wind turbine structure is computed under fatigue loads exerted in single direction, the results of omnidirectional fatigue analysis are more reasonable.

Abstract: Battery charging is the most substantial issue in battery management systems, and the intelligent charger can provide stable and reliable energy conversion to electric vehicles. So the research of high power intelligent battery charger becomes very important. This paper introduces the main concept of battery charging of an electric vehicle, and studies the working principle and hardware scheme of an intelligent charging system, and researches the material performance. And based on research results, we will propose desirable characteristics of charger for public use.

Abstract: This paper used solidworks software to build 3-D model of a certain Heavy Vehicle Part, then analyzed the model strain state under typical operation condition by ANSYS,

Abstract: Agricultural mechanization was a research emphasis in mechanical engineering and one of the basic content of modern agriculture, it possessed very significant effect on increasing agricultural productivity. The present status and development tendency on agricultural mechanization at home and abroad were expounded in this paper. Through the analysis of agricultural mechanization to modern agriculture, the theories of promoting the development of precision agriculture, agricultural robots, automatic control were put forward. At last, some advices on speeding up agricultural mechanization in mechanical engineering were given.

Abstract: The control working condition and the control load direction of the typical Tripod substructure for the offshore wind turbine are studied by the finite element analysis software SACS. The results show that the different control criterions are corresponding to the different control working conditions for the Tripod substructure of the offshore wind turbine, and the control load directions vary with the structure form and the marine environments. Therefore, the static and dynamic analysis of the offshore wind turbine substructure in the single or limited load directions cant reflect the static and dynamic characteristic of the structure sufficiently. The multidirectional static and dynamic analysis of the offshore wind turbine structure has to be carried out.

Abstract: The PID control algorithm is simple. But when it controls DC servo motor of nonlinearity, delay and strongly couple, its dynamic control performance is poor. Fuzzy control which is essentially equivalent to a nonlinear PD control has poor steady state performance. Fuzzy-PI dual-mode control simultaneously has PID control's steady-state performance and fuzzy control's dynamic performance. The step response simulation results shows that Fuzzy-PI controls rise time is 8sec and that the overshoot and steady-state error are close to 0. It has stronger anti-interference ability, higher dynamic performance and higher steady state performance.

Abstract: In geomagnetic aided navigation (GAN), the vehicle is expected to traverse the areas with excellent matching suitability in order to obtain high matching precision. The route planning problem under matching suitability constraints is studied based on particle swarm optimization (PSO) algorithm in this article. Firstly, the PSO algorithm is briefly introduced and the expanding space of route nodes is determined with the maneuverability constraints of the vehicle. Then the minimum movement distance, the ability of avoiding threats and the proximity to suitable-matching areas are considered to construct the fitness function of PSO algorithm. Further the route planning method under matching suitability constraints is proposed. Experimental results show that the proposed method is effective, and the vehicle can successfully avoid the threats and can traverse the suitable-matching areas.

Abstract: In recent years, water conservancy cause has been developing rapidly in China, the gravity dam risk assessment model has a great significance for the study. Firstly, the paper introduces risk and risk assessment. Then, the thesis uses expert investigation method to recognize the main risk factors of the project, analyze the probability and loss of risk factors of the gravity dam ; and based on the R = P × C model and fuzzy comprehensive evaluation method.Finally, we obtain the level of each risk factor, providing the basis for the prevention of the risks.