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Dynamic Modeling and Torsional Vibration Analysis of Crankshafts Equipped with DMF & CPVA
, M.Sc. Thesis Sharif University of Technology ; Sayyadi, Hassan (Supervisor)
Abstract
Torque variations caused by intermittent combustion and inertia effects of reciprocating components, exert significant torsional excitation on crankshaft of internal combustion engines. These excitation induces considerable torsional vibration on crankshafts. Therefore, modeling and analysis of crankshaft torsional vibration and absorber systems, especially in automobiles engine that crankshaft tolerate high amplitude excitations coupled with heavy inertia effects has high importance. In this study, ability of centrifugal pendulum vibration absorber and dual mass flywheel which used in rotating machinery for vibration reduction, will be examined. At first, cranktrain will be torsionaly...
Designing of Gyrover and Controlling it with Fuzzy-pade’ Method
, M.Sc. Thesis Sharif University of Technology ; Zohoor, Hassan (Supervisor) ; Sohrabpour, Saeed (Supervisor)
Abstract
Gyrover is a kind of robot which can move with only one single wheel. In this robot, all the mechanical and electronics’ systems are placed in the wheel of robot. So the wheel of robot is the boundary which separates the inner equipment of gyrover with outside environment. In this robot, only one wheel is used for moving, so the amount of friction of movement in gyrover robot is less in comparison with two and more wheeled vehicles. Because of this gyrover can move to more domains. Gyrover robot can move both on land and water. Gyrover robot is not intrinsically stable which means that it cannot stand on ground. So for stability of gyrover another dynamic system should be used. The best...
Design, Manufacturing and Testing a Micro Hydro Turbine Governor Using Commercial Controller
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
Lots of micro hydropower potentials are spread all around Iran country. They have the capability to produce electricity for workhouses, residential areas, agricultural and animal husbandries and recreational tourism centers. Hence, Sharif University of Technology and Iran Water and Power Resources Development Corporation decided to design and produce three types of hydro micro turbines to cover all range of micro hydropower potentials available in Iran. These three types of micro turbines are Pelton, Banki and Axial and they are designed in order to cover high, middle and low heads in sequence. Frequency control of micro hydropower plants is so vital due to plant off-grid. The most prevalent...
Introducing a dimensionless number as tank selector in hybrid solar thermal energy storage systems
, Article Journal of Mechanical Science and Technology ; Volume 25, Issue 4 , 2011 , Pages 871-876 ; 1738494X (ISSN) ; Zohoor, H ; Sharif University of Technology
Abstract
Using hybrid energy storage system is a method for increasing the storage capability of solar thermal energy. If multiple energy storage devices with complementary performance characteristics are used together, the resulting system will be a 'Hybrid Energy Storage System'. In other words, a Hybrid Energy Storage System (HESS) has several media available for storage at any time. In this way, increase in storable energy is obtained without increasing collectors' area. When there are more than one storage mediums, the system should be able to choose the best medium for storing energy according to the conditions. In the previous works, an optimizer program was used to find the proper medium...
Introducing GyroSym: a single-wheel robot
, Article International Journal of Dynamics and Control ; Volume 8, Issue 2 , 2020 , Pages 404-417 ; Abedin Nasab, M. H ; Liu, G ; Sharif University of Technology
Springer
2020
Abstract
In this paper, GyroSym, a compact highly-stable single-wheel robot is introduced. Symmetrical flywheels have been used as its stabilization mechanism to keep the wheel upright. Thanks to the type of the flywheel used, the dynamic equations of the robot is simplified, the torque needed to tilt the spin axis is reduced, and the space is drastically minimized. Besides, a centrifugal clutch is used to smooth the motion of the robot in forward motion. Two controllers, fuzzy and fuzzy-Padé, were implemented based on their ability to stabilize the robot. Although both prevented the GyroSym from falling over, neither can entirely cancel out the effects of nonlinear behaviors that is present in the...
Potential use of cold thermal energy storage systems for better efficiency and cost effectiveness
, Article Energy and Buildings ; Volume 42, Issue 12 , 2010 , Pages 2296-2303 ; 03787788 (ISSN) ; Mozafari, A ; Ahmadi, A ; Esmaili, P ; Shayesteh, M ; Sarkhosh, M ; Dincer, I ; Sharif University of Technology
Abstract
The present article deals with the employment of combined heat and power (CHP) micro gas turbines using natural gas and cold thermal energy storage system (CTES) in Tehran (with mild climate), Bandarabas (with hot and humid climate) and Kerman (with semi-hot climate). A micro CHP produces electricity to meet the electrical energy needs of the building, and it is also considered to meet part of the heating, cooling and domestic hot water energy needs through a heat pump and refrigeration system. A detailed study considering the effect of CTES system on the selection of micro gas turbines of a residential building located in Tehran is performed. The results show that since the number of micro...
Positioning and tracking control of an amphibious single wheel robot
, Article 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 11 , 2009 , Pages 545-551 ; 9780791848722 (ISBN) ; Alizadeh, D ; Sharif University of Technology
2009
Abstract
Amphibious single wheel robot consists of a sharp-edged wheel actuated by a spinning flywheel for steering and a drive motor for propulsion. The spinning flywheel acts as a gyroscope to stabilize the robot and also can be tilted to achieve steering. In this paper, the kinematics of a single wheel robot in water, Gyrover, is analyzed and then a simple mechanism for driving it is proposed. In previous studies, Lagrange approach is used for hydrodynamic modeling of the robot. A nonlinear position controller is designed to bring the robot to any desired position. Based on the designed controller, a tracking controller is augmented to the robot. For simplicity the added mass effect has been...
Dynamic anlysis of an amphibious single wheel robot part1: Moving in straight path
, Article 31st Mechanisms and Robotics Conference, presented at - 2007 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE2007, Las Vegas, NV, 4 September 2007 through 7 September 2007 ; Volume 8 PART B , 2008 , Pages 927-932 ; 0791848027 (ISBN); 9780791848029 (ISBN); 0791848094 (ISBN); 9780791848098 (ISBN) ; Alasty, A ; Sharif University of Technology
2008
Abstract
A single wheel, gyroscopically stabilized robot is a sharpedged wheel actuated by a spinning flywheel for steering and a drive motor for propulsion. The spinning flywheel acts as a gyroscope to stabilize the robot and it can be tilted to achieve steering. In this paper first the kinematics of a single wheel robot, like Gyrover, in water is considered and then a simple mechanism for its movement in water is proposed. After hydrodynamic analysis of the robot a complete dynamics model is designed with Lagrange energy method. The only simplification used here is neglecting the added mass effect in hydrodynamic analysis. This complete model can be used for examining the behavior of the robot in...
Stability control of an Amphibious single wheel robot
, Article ASME International Mechanical Engineering Congress and Exposition, IMECE 2007, Seattle, WA, 11 November 2007 through 15 November 2007 ; Volume 9 PART B , 2008 , Pages 1465-1472 ; 0791843033 (ISBN); 9780791843031 (ISBN) ; Alasty, A ; Sharif University of Technology
2008
Abstract
Single wheel robots are typically those kinds of robots which contain all the necessary mechanizations, namely the stabilization and driving mechanizations, within a shell-liked housing appearing analogous to a wheel. These robots have proved to be useful in various fields of industry due to their advantages of giving high instant acceleration and maintaining high cruise speeds for considerable amount of time in addition to being compact and small. It is a sharp-edged wheel actuated by a spinning flywheel for steering and a drive motor for propulsion. The spinning flywheel acts as a gyroscope to stabilize the robot and it can be tilted to achieve steering. In this paper first the kinematics...