Design,Modeling and Control of a Simulator of an Aircraft Maneuver in the Wind Tunnel Using Cable Robot

International Journal of Control, Automation and Systems - In this paper, a new controllable simulator is proposed and modeled by which, experimental tests of the aircraft’s models can be...     

Computer simulation of the optical properties of high-temperature cermet solar selective coatings

A computer simulation is developed to calculate the solar absorptance and thermal emittance of various configurations of cermet solar selective coatings. Special attention has been paid to those material combinations, which are commonly used in high-temperature solar thermal applications. Moreover, other material combinations such as two-, three- and four-cermet-layer structures as solar selective coatings have been theoretically analyzed by computer simulation using three distinct physical models of Ping Sheng, Maxwell–Garnett and Bruggeman. The novel case of two-cermet-layer structure with different cermet components has also been investigated. The results were optimized by allowing the program to manipulate the metal volume fraction and thickness of each layer and the results compared to choose the best possible configuration. The calculated results are within the range of 0.91–0.97 for solar absorptance and 0.02–0.07 for thermal emittance at room temperature.     

Dyamic modelig ad trackig cotrol of a car with $$ trailers

Tractor–trailer systems as multibody modular robotic systems have been widely used to increase load transportation capacity. Control of these systems started from motion aid facilities in human-driven vehicles to fully autonomous mobile robots in recent years. The mobility of these systems is restricted due to the presence of nonholonomic constraints of wheels and also to the system severe underactuated nature. Several control problems are under research for autonomous navigation of such systems. Trajectory tracking is one of the main problems in the context of autonomous nonholonomic systems. In this paper, dynamic modeling and control of a car with \(n\) trailers have been developed. First, a dynamic model of the system is obtained. Next, an output feedback kinematic controller and a feedback linearization kinetic controller have been used for tracking control of the system. Finally, experimental results are presented to show the merits of the proposed method.     

Design, construction and performance testing of a new system for energy saving in rural buildings

Drying fruit, heating residential buildings and providing a hot water supply in villages all consume energy. Using fossil fuel for these purposes creates pollution and costs too much. In contrast, the use of solar energy in these applications leads to a noticeable decrease both in pollution and investment costs. In this study, a new solar system was designed and tested in order to reduce energy usage in rural residential buildings and the food drying industry. As the peaks of energy consumption in the proposed system are not simultaneous, this new system is very effective in reducing energy consumption, controlling energy peaks and reducing environmental pollution. This system has the ability to provide the required energy in both summer and winter modes. In the summer mode, the energy supply is used for providing hot water and drying agricultural products, while in winter mode it is used for rural residences heating and hot water supply. Drying time has been varied between 51.23 and 42.45 h according to type of application, and average temperature difference between room and ambient is almost nearly 10 °C with different air heaters. The system includes energy supply and storage equipment, solar dryers, water collectors and rectangular, triangular, trapezoidal and double-pass with longitudinal fins air heaters. The system was tested in Iran for drying apricots, heating rural residential buildings and supplying hot water for domestic use, meanwhile, the energetic and exergetic efficiency of the system was calculated 37.3-61.3 and 3.2-9.7 respectively for different types of installations.     

Analytical model of atrium for heating and ventilating an institutional building naturally

The incorporation of an atrium into a building will not automatically lead to energy savings. The energy consumption of a parent building may be increased if compared with a similar-shaped building without an atrium. This is due to the increased need for artificial lighting, mechanical ventilation. In practice, atria are rarely incorporated in designs for the main purpose of energy saving. This research presents the relation between the passive heating and ventilating effect and the dimension of an atrium and the parent building. To achieve this purpose, an institutional single zone three story building is assumed in Tehran metrological condition. The fictitious building has an atrium and correlates with three elements of wall, glazing and air. Heat balance equation has been written for each element. By substituting the temperature profile of the atrium in the set of temperature equations, temperature of each element has been acquired. The results are in good agreement with empirical results which other researchers gathered.     

Comparative analysis of three numerical methods for estimating the onshore wind power in a coastal area

Although there are many studies concerning the estimation of wind potential in different locations of Iran, an adequate evaluation of wind power for onshore locations of this country has not been investigated yet. The purpose of this research is to evaluate the potential of onshore wind in the south of Iran along the Gulf of Oman by comparing three Weibull numerical methods. In the first step, it became clear that the maximum likelihood method (MLM) compared to other methods represented the actual wind data with the lowest error rate and therefore it was selected as an accurate statistical distribution to model the wind speed of the investigated location. Using the MLM, the estimation of wind speed characteristics as well as the techno-economic evaluation of different wind turbines has been investigated. It was concluded that both technically and economically the studied area does not have sufficient wind power for the development of large-scale or grid-connected wind turbines. However, it may have enough power for non-grid-connected mechanical applications, such as wind generators for water pumping. Therefore, in the last part of this paper, an investigation of water pumping potential of the studied site by using adequate and modern wind turbines with lower start-up wind speed was recommended for future studies. Furthermore, it was suggested that the current methodology used in this research could be employed and extended in future studies to evaluate the wind potential of all onshore locations of Iran including onshore locations along the Persian Gulf and Caspian Sea.     

Modeling and control of uncertain multibody wheeled robots

Multibody System Dynamics - This paper addresses the trajectory tracking problem of nonholonomic vehicles in the presence of uncertainties. Kinematic perturbations stem from skidding of wheels,...     

Experimental investigation for optimization of design parameters in a rectangular duct with plate-fins heat exchanger by Taguchi method

This study presents the determination of optimum values of the design parameters in a heat exchanger with a rectangular duct by using Taguchi method. The heat exchanger has plate-fins containing periodically interrupted diverging and converging channel flow domains. The experimental investigation for the established heat exchanger involves short rectangular fins attached in 8 × 8 arrays to a surface having various inclination angles. The effects of the six design parameters such as the ratio of the duct channel width to height, the ratio of the winglets length to the duct channel length, inclination angles of winglets, Reynolds number, flow velocity and pressure drop are investigated. In the Taguchi experimental design method, Nusselt number and friction factor are considered as performance parameters. An L₂₅ (5⁶) orthogonal array is chosen as an experimental plan for the design parameters. The analysis of Taguchi method conducted with an optimization process to reach minimum pressure drop (friction factor) and maximum heat transfer (Nusselt number) for the designed heat exchanger. Experimental results validated the suitability of the proposed approach.     

Design Analysis of Impinging Jet Array Heat Transfer From a Surface With V-Shaped and Convergent–Divergent Ribs by the Taguchi Method

In this work, the effects of the impingement plate geometry, Reynolds number, jet-plate distance-to-jet diameter ratio, and the jet diameter-to-rib height ratio on the impingement jets were investigated using the Taguchi experimental design method. The heat transfer measurements over a surface with V-shaped ribs (V-SR) and convergent-divergent shaped ribs (CD-SR) by a circular impinging jet array were investigated using a thermal infrared camera. Both V-SR and CD-SR configurations, with an angle of 45°, were considered. Both projected and total Nusselt numbers were considered as performance statistics. After the data on each quality characteristic were obtained from the orthogonal arrays, a main effect analysis and analysis of variance (ANOVA) were conducted to determine the parameters that had significant effects on these quality characteristics. The L₃₂ (2¹ × 4³) orthogonal array was selected as an experimental plan for the four parameters. The Taguchi method was applied with an optimization process to reach the maximum heat transfer. Experimental results validated the suitability of the proposed approach. The best heat transfer performance was obtained with the V-SR arrangements.