On the Analysis and Synthesis of Type I Spatial 6R Overconstrained Mechanism

Author(s):  
Chung-Ching Lee

Abstract Based on matrix algebra and its differentiation, we derive the general analytical kinematic solutions and simple stationary configurations of Type I spatial 6R overconstrained mechanism. This mechanism is a general form of Sarrus 6R mechanism. Its coupler point of a certain link has straight-line motion and this is used for the synthesis of straight-line mechanism by the optimization method. Moreover, a graphical synthesis technique with descriptive geometry is presented to design the linkage type of double-toggle mechanism for spatial clamping device. Two numerical examples are given for illustration and their results are verified by computer animation of motion.

Author(s):  
Chung-Ching Lee ◽  
Hong-Sen Yan

Abstract Based on matrix algebra, we derive the general analytical kinematic solutions of Type II movable spatial 6R mechanism with three adjacent parallel axes. This 6R mechanism was previously identified by the authors, and one of its special form is proposed as the retracting and wheel twisting mechanism for aircraft landing gears. A graphical synthesis technique by descriptive geometry is presented for the kinematic synthesis of the landing gear mechanism. A numerical example is given, and the mobility of this design is verified by computer animation of motions.


1960 ◽  
Vol 38 (1) ◽  
pp. 78-99 ◽  
Author(s):  
A. Ishimaru ◽  
G. Held

Part I considers the problem of determining the source distribution over a circular aperture required to produce a prescribed radiation pattern. In particular, the problem of optimizing the narrow broadside pattern from a circular aperture is discussed in detail and an improved design method over Taylor's for line source is devised. Numerical examples are given.Part II deals with the analysis of the radiation pattern from a circular aperture from γ1 to γ2 with the traveling wave type source functions. Expressions suitable to the analysis and the synthesis are obtained and the narrow-beam and shaped-beam synthesis are discussed.


2009 ◽  
Vol 67 ◽  
pp. 191-196 ◽  
Author(s):  
Lubna Hashmi ◽  
M.S. Qureshi ◽  
R.N. Dubey ◽  
M.M. Malik ◽  
Ishrat Alim ◽  
...  

A broad range of II-VI materials has been investigated in order to produce light in the full visible range for optoelectronic applications. The present investigation was carried out for the spectroscopic analysis and synthesis of wide band gap cadmium sulfide nanoparticles. Large-band gap semiconductors have the added advantage in that; they can support higher electric field before breaking down, which means that they can be used for high-power electronic devices.Synthesis has been carried out using colloidal synthesis technique at low temperature. The size, stabilization and optical properties were studied using UV-vis Spectrophotometer and Spectroflourometer. Further, the structural studies of synthesized powder were carried out using X-ray diffraction technique; which also confirms the formation of desired product. The capping ligand and the impurities present in the sample were characterized by Fourier transform infra red spectroscopy. Synthesized CdS powder dispersed in aqueous media gave the value of 193 nm for the onset wavelength using UV-vis spectrophotometer, which is significantly blue-shifted compared to bulk CdS and shows the quantum confinement effect. From the onset wavelength the radius of CdS quantum dot calculated using the Brus equation was found to be ca. 0.7 nm.


2013 ◽  
Vol 834-836 ◽  
pp. 1290-1294
Author(s):  
Xin Qin Liu

Mechanicalmethods were employed to study the motion and force transmission performance ofa kind of connecting rod slider mechanism with a curved edge driving component.The deduction methods and the computation formulae of the slider displacement,velocity, acceleration and the executive force gain coefficient were given.Considering two cases of the driving components with straight line edge andexponential function edge, the numerical examples was computed respectively,the results show that the former one is suitable for the force transmission andcan be used in the grip design and the other one is suitable for the motiontransmission which can be used in the fast moving mechanism


Author(s):  
Ning-Xin Chen ◽  
Shin-Ming Song

Abstract The leg mechanism of a walking machine has a strong influence on the performance of the machine. A successful leg mechanism should be energy efficient, compact in size, strong and simple. In order to achieve good energy efficiency, a walking machine leg should be able to generate an exact or approximate straight line at the foot with only one driving actuator. This paper deals with the synthesis and analysis of a new leg mechanism — the planetary gear leg mechanism. Four types of planetary gear legs are studied. By the SUMT optimization method, a 20 inch tall leg is able to generate an approximate straight line trajectory with a maximum deviation of 0.12805 inches in a 20 inch stroke. The direct and inverse kinematics and velocities of the legs are analyzed. Also, the distribution of actuator force/moment during walking are studied. The results show that this leg design has great potential to be used as a practical walking machine leg.


2010 ◽  
Vol 69 (3) ◽  
Author(s):  
W. F. Harris

For a dioptric system with elements which may be heterocentric and astigmatic an optical axis has been defined to be a straight line along which a ray both enters and emerges from the system.  Previous work shows that the dioptric system may or may not have an optical axis and that, if it does have one, then that optical axis may or may not be unique.  Formulae were derived for the locations of any optical axes.  The purpose of this paper is to extend those results to allow for reflecting surfaces in the system in addition to refracting elements.  Thus the paper locates any optical axes in catadioptric systems (including dioptric systems as a special case).  The reflecting surfaces may be astigmatic and decentred or tilted.  The theory is illustrated by means of numerical examples.  The locations of the optical axes are calculated for seven optical systems associated with a particular heterocentric astigmatic model eye.  The optical systems are the visual system, the four Purkinje systems and two other nonvisual systems of the eye.  The Purkinje systems each have an infinity of optical axes whereas the other nonvisual systems, and the visual system, each have a unique optical axis. (S Afr Optom 2010 69(3) 152-160)


Author(s):  
Constantinos Mavroidis ◽  
Bernard Roth

Abstract This paper presents a new systematic method for dealing with overconstrained mechanisms, and describes how the method was used to discover new overconstrained mechanisms and correct errors in several previously published overconstraint conditions. With this one method we are able to verify all previously known overconstrained mechanisms. In addition, this method yields the input-output equations of any single-loop overconstrained mechanism. For all new and corrected overconstrained mechanisms, numerical examples of input-output curves are presented.


2010 ◽  
Vol 450 ◽  
pp. 397-400
Author(s):  
Hsin Rau ◽  
Kuo Hua Cho ◽  
Yi Hsiang Wang

. The study models multi-characteristics inspection for inspection allocation problems with workstations of attribute data in serial production systems. Either 100% or 0% inspection is performed and Type I and Type II errors are considered. In addition, this study considers three possibilities of treatment of detected nonconforming units, namely, repair, rework and scrap. With the above considerations, a profit model is developed for optimally allocating inspections. Moreover, a genetic algorithm is used to solve the problem and it is proved to have much less computation time, compared with an optimization method based on complete enumeration, especially when number of workstations and characteristics becomes more.


Author(s):  
Kimberly Ryland ◽  
Carl A. Nelson ◽  
Thomas Hejkal

Retinopathy of Prematurity, caused by abnormal blood vessel development in the retina of premature infants, is a leading cause of childhood blindness. It is treated using laser photocoagulation. Current methods require the surgeon to assume awkward standing positions, which can result in injury to the surgeon if repeated often. To assist surgeons in providing quality care and prevent occupational injury, a new infant surgical table was designed. The engineered solution is an attachment to a standard surgical table, saving cost and space. This takes advantage of the adjustable height and tilt provided by the standard table, while 360° rotation designed into the attachment allows the surgeon to sit during surgery. The critical cords and tubes are routed through the attachment to avoid pulling and kinking. A four-bar locking mechanism allows easy attachment to standard medical railing. Finally, a straight line mechanism provides positive locking of the rotation, allowing precise positioning of the infant.


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