Papers by Keyword: Control

Abstract: Lower extremity exoskeletons are wearable robot manipulators that integrate human intelligence with the strength of legged robots. Recently, lower extremity exoskeletons have been specifically developed for rehabilitation, military, industrial applications and rescuing, heavy-weight lifting and civil defense applications. This paper presents controller design of a lower-extremity exoskeleton for a load carrying human to provide force feedback control against to external load carried by user during walking, sitting, and standing motions. Proposed exoskeleton system has two legs which are powered and controlled by two servo-hydraulic actuators. Proportional and Integral (PI) controller is designed for force control of system. Six flexible force sensors are placed in exoskeleton shoe and two load cells are mounted between the end of the piston rod and lower leg joint. Force feedback control is realized by comparing ground reaction force and applied force of hydraulic cylinder. This paper discusses control simulations and experimental tests of lower extremity exoskeleton system.

Abstract: This paper takes project management information systems as the main object of studying,it applies the theory and means of Project Management Knowledge System,and the specific features of construction project management on the research. It makes detail analysis and deep study to the application of WBS for project management and construction project information classification system.

Abstract: The prevention and control of pollution is an important technical link in haploid breeding of wheat. From the pollution types,causes and prevention methods in the process of wheat anther culture to analyze how to reduce pollution problems appeared in the tissue culture,so as to achieve the purpose of decreasing the cost of wheat breeding,and improving the efficiency of breeding purposes.

Abstract: Nowadays with the high fuel costs, the stress for energy saving and green emission of construction machineries, while not sacrifice of the operating performance, safety and dependableness, particularly for hydraulic excavators (HYEXs), are extremely exaggerated. As a result, electro-hydraulic actuators (EHA), that is promoted and with success applied to industry, is recently introduced to HYEXs. The aim of this paper is to propose a new style of excavator - electrical excavator (ELEX) - with energy saving capability using the EHAs. Each of the hybrid actuators is driven by an electrical motor/generator for retrieving a potential energy or a kinetic energy at the time of lowering or slewing stoppage of the excavator. An excavator having a hybrid boom system (HBS) is analyzed. Finally, operating efficiency and energy consumption of the projected excavator area unit are clearly studied. Keywords: Hydraulic excavator; electric excavator; electro-hydraulic actuator; control

Abstract: Exposure to welding fumes and its related hazards has always been a matter of serious concern. The mass and composition of fumes from welding depends on several factors. A detailed knowledge of these factors is necessary for understanding the mechanism of fume formation and developing suitable control strategies. This paper gives a literature overview on the various factors affecting welding fumes and strategies for controlling it. The paper focus on types of welding process like Manual Metal Arc Welding (MMAW) or Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW), Flux Core Arc Welding (FCAW), Gas and Tungsten Arc Welding (GTAW). The research in the area of controlling fumes at the source has grown rapidly recently. Still, effective methods have hardly been explored. Improving arc stability by addition of materials with low ionization potential to the welding electrode lead to promising new research directions.

Abstract: Deriving inspiration from the propulsion methods of squids, a pulsatile jet propulsion system is adopted in a robotic model. A squid-like direction control mechanism, which can direct the jet along any direction on a hemispherical work volume, is also implemented. To obtain a suitable robot velocity (_v) and a propulsive efficiency (η_p) for testing this mechanism, the stroke ratio (L/D) and outlet diameter are varied and the _v and the η_p of various alternatives are estimated experimentally using vision analysis. A Stroke ratio of 3.78 and an outlet diameter of 25.4 mm were found suitable and employed for testing the mechanism. When the jet is deflected by 60° in the horizontal plane, the robot rotates about its centroid, signifying excellent maneuverability. Reverse motion was also demonstrated by removing inlet valves and blocking the outlet through the direction control mechanism. The performance of the direction control mechanism indicates that the robotic model was a feasible alternative to conventional screw-propelled aquatic robots.

Abstract: This article from the detection quality control measures, testing the quality assurance system, testing organization and management systems, testing technology and other aspects of the work are discussed assay impartiality and reliability.

Abstract: Given the current supervisory work on site supervision and a clear understanding of the role of superficial, it is necessary to work in this role to be scientifically demonstrated, to obtain a unified understanding, to improve work quality.

Abstract: In the present paper, a combined method of large eddy simulations for non-premixed combustion in a turbulent flow coupled with proper orthogonal decomposition of instantaneous velocity, pressure and temperature fields is developed in order to identify the effect of coherent structure and to obtain a reduced order model for control model. First we investigate the reacting flow using Large Eddy Simulations technique. This physical model is pertinent to internal flows inside the hybrid rocket motors. The turbulence-combustion interaction is based on a combination of finite rate/eddy dissipation model applied to a reduced chemical mechanism with four reactions. Next, the paper refers to the derivation of a Reduced Order Model (ROM) for the same problem, based on the Proper Orthogonal Decomposition (POD) technique. ROMs are used to obtain fast and accurate results, needed in the areas of flow control. The flow and thermal fields obtained with ROMs are compared with the ones obtained from the full simulation and an analysis on the number of modes required to achieve the desired accuracy is presented. Finally, a static control technique is proposed.

Abstract: With the world's population growth the industrialization process and the unreasonable use of the environment,soil pollution problem has been increasingly prominent, the soil will become another shortage resource. This article introduces akind of soil pollution and restoration simulation system,the whole system simulates proliferation, migration and transformation process of different pollutants in different soil types, different hydrogeological environment three-dimensional space. The systerm also uses physical and chemical, biological and other repair method to repair contaminated soil. The use of LabVIEW graphical programming language to design PC man-machine interface looks simple and intuitive. Based on LabVlEW serial communication function, we develop the LabVIEW and PLC communication driver and achieve the real-time monitoring of the whole system ,which provides equipment and data support for the pollution of the soil.