scholarly journals Measurement of Rigidity Change of Preload Switching Spindle

2012 ◽  
Vol 6 (2) ◽  
pp. 175-179 ◽  
Author(s):  
Taku Yamazaki ◽  
◽  
Atsushi Matsubara ◽  
Shinya Ikenaga ◽  
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Rigidity ◽  
High Speeds ◽  
Loading Device ◽  
Magnetic Loading ◽  
Simulation Results ◽  
Load Displacement ◽  
Low Speeds ◽  
Relationship Of

High performance milling spindles with high rigidity and high speed are required for high productive machining. A preload switching spindle has been designed to obtain high rigidity at low speeds while avoiding bearing burn at high speeds. In this report, the load-displacement relationship of a preload switching spindle is measured with a non-contact magnetic loading device. Measurement and simulation results are compared to clarify the rigidity change by preload switching.

Development of Dynamic Loading Device for Rotating Spindle of Machine Tools

2012 ◽  
Vol 523-524 ◽  
pp. 544-549
Author(s):  
Ryota Sawamura ◽  
Shinya Ikenaga ◽  
Atsushi Matsubara
Keyword(s):  
Dynamic Loading ◽  
Machine Tools ◽  
High Speed ◽  
High Performance ◽  
Loading Rate ◽  
Electric Response ◽  
Loading Test ◽  
Loading Device ◽  
Magnetic Loading ◽  
The Magnetic Field

High performance milling spindles, which have high rigidity and high speed, are required for high productive machining. In order to evaluate the rigidity change of the spindle, authors has been developed a magnetic loading device. This device provides attractive force in radial direction to a dummy tool attached to a spindle. By using this device, the static stiffness of the rotating spindle has been successfully evaluated. However the loading rate could not be controlled due to the electric response lag caused by the magnetic field. To solve this problem, electric response of the coil-tool system with the air gap is analyzed and the dynamic response is estimated. The air-gap's influence on the load was also evaluated. Based on the analysis, a dynamic loading test is designed carried out for the measurement of the rigidity of a machine tool spindle.

Path-Following Steering Control for Articulated Vehicles

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
B. A. Jujnovich ◽  
D. Cebon
Keyword(s):  
High Speed ◽  
Path Following ◽  
Steering Control ◽  
Active Steering ◽  
High Speeds ◽  
Wide Range ◽  
Articulated Vehicles ◽  
Speed Range ◽  
Heavy Goods Vehicles ◽  
Low Speeds

Passive steering systems have been used for some years to control the steering of trailer axles on articulated vehicles. These normally use a “command steer” control strategy, which is designed to work well in steady-state circles at low speeds, but which generates inappropriate steer angles during transient low-speed maneuvers and at high speeds. In this paper, “active” steering control strategies are developed for articulated heavy goods vehicles. These aim to achieve accurate path following for tractor and trailer, for all paths and all normal vehicle speeds, in the presence of external disturbances. Controllers are designed to implement the path-following strategies at low and high speeds, whilst taking into account the complexities and practicalities of articulated vehicles. At low speeds, the articulation and steer angles on articulated heavy goods vehicles are large and small-angle approximations are not appropriate. Hence, nonlinear controllers based on kinematics are required. But at high-speeds, the dynamic stability of control system is compromised if the kinematics-based controllers remain active. This is because a key state of the system, the side-slip characteristics of the trailer, exhibits a sign-change with increasing speeds. The low and high speed controllers are blended together using a speed-dependent gain, in the intermediate speed range. Simulations are conducted to compare the performance of the new steering controllers with conventional vehicles (with unsteered drive and trailer axles) and with vehicles with command steer controllers on their trailer axles. The simulations show that active steering has the potential to improve significantly the directional performance of articulated vehicles for a wide range of conditions, throughout the speed range.

High-Speed and High-Accuracy Schemes of Coordinate Calculation and End Point Judgment for Elliptic Interpolation

2012 ◽  
Vol 217-219 ◽  
pp. 2664-2668
Author(s):  
Shi Yong Wang ◽  
Di Li
Keyword(s):  
Motion Control ◽  
High Speed ◽  
High Performance ◽  
High Accuracy ◽  
Interpolation Point ◽  
End Point ◽  
Sample Method ◽  
Relationship Of ◽  
Approximation Calculation

To implement high-speed and high-accuracy elliptic interpolation required in high-performance motion control, novel coordinate calculation and end point judgment schemes are proposed. Data Sample method is used for coordinate calculation. High accuracy is guaranteed by avoiding approximation calculation of interpolation points. Exact end point judgment is constructed based on the position relationship of the current interpolation point, the next interpolation point and the end point to avoid incomplete interpolation or over interpolation of elliptic trajectories. The proposed schemes feature fewer amounts of calculation and high accuracy and can produce any elliptic trajectories.

The Role of High Performance Foil Bearings in Advanced, Oil-Free, High-Speed Motor Driven Compressors

2003 ◽  
Author(s):  
James F. Walton ◽  
Michael J. Tomaszewski ◽  
H. Heshmat
Keyword(s):  
High Speed ◽  
High Performance ◽  
Development Program ◽  
Foil Bearings ◽  
High Speeds ◽  
Start Up ◽  
Rolling Element ◽  
Temperature Capability ◽  
Full Speed ◽  
Bearing System

The demand for high power density, reliable, low maintenance, oil-free turbomachinery imposes significant demands on the bearing system. The full benefits of high speed, motor driven machines, for example are realized at speeds exceeding the capabilities of rolling element bearings. The high speeds, and requirement for oil-free operation in fuel cell applications also make conventional liquid lubricated bearings an undesirable alternative. The modern, oil-free foil bearing provides an excellent alternative, with its low power loss, damping for smooth high-speed operation and shock tolerance, elevated temperature capability and long maintenance free life. In this paper, the application of modern foil bearings to two different high-speed, oil-free compressors is discussed. In each application, foil bearings support a multi-component rotor operating at speeds above 70,000 RPM. Stable and reliable operation over the full speed range is demonstrated in each case. These applications also required low bearing start-up torque for compatibility with the torque characteristics of the integral motor. This work discusses the rotor bearing system design, the development program approach, and the results of testing to date.

Performance of Air-Lubricated Hydrodynamic Bearing Spindles for Laser Scanners

1991 ◽  
Vol 113 (3) ◽  
pp. 609-614 ◽  
Author(s):  
K. Tanaka ◽  
H. Muraki
Keyword(s):  
High Speed ◽  
High Performance ◽  
Experimental Results ◽  
Hydrodynamic Bearing ◽  
Vibration Resistance ◽  
High Speeds ◽  
Laser Printers ◽  
Laser Scanners

This paper reports on the performance of air-lubricated bearing spindles for high-speed laser scanners using newly developed bearings. Experimental results confirmed that these spindles have adequate performance including floating stability, endurance, vibration-resistance at high-speeds, and start-stop endurance for laser scanners. These spindles are already mass-produced and used in laser printers and digital color copiers, so their high performance and endurance are proven.

scholarly journals Review on the Effect of the Phenomenon of Cavitation in Combustion Efficiency and the Role of Biofuels as a Solution against Cavitation

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7265
Author(s):  
Ludovic Lamoot ◽  
Brady Manescau ◽  
Khaled Chetehouna ◽  
Nicolas Gascoin
Keyword(s):  
High Speed ◽  
High Performance ◽  
Research Work ◽  
Combustion Process ◽  
Energy Transition ◽  
Combustion Efficiency ◽  
Review Article ◽  
Cavitation Phenomenon ◽  
Heat Engines ◽  
High Speeds

Concerning the problem of wanting the performance of heat engines used in the automotive, aeronautics, and aerospace industries, researchers and engineers are working on various possibilities for improving combustion efficiency, including the reduction of gases such as CO, NOx, and SOx. Such improvements would also help reduce greenhouse gases. For this, research and development has focused on one factor that has a significant impact on the performance of these engines: the phenomenon of cavitation. In fact, most high-performance heat engines are fitted with a high-speed fuel supply system. These high speeds lead to the formation of the phenomenon of cavitation generating instabilities in the flow and subsequently causing disturbances in the combustion process and in the efficiency of the engine. In this review article, it is a question of making a state-of-the-art review on the various studies which have dealt with the characterization of the phenomenon of cavitation and addressing the possible means that can be put in place to reduce its effects. The bibliographic study was carried out based on five editors who are very involved in this theme. From the census carried out, it has been shown that there are many works which deal with the means of optimization that must be implemented in order to fight against the phenomenon of cavitation. Among these solutions, there is the optimization of the geometry of the injector in which the fuel flows and there is the type of fuel used. Indeed, it is shown that the use of a biofuel, which, by its higher viscosity, decreases the effects of cavitation. Most of these jobs are performed under cold fluidic conditions; however, there is little or no work that directly addresses the effect of cavitation on the combustion process. Consequently, this review article highlights the importance of carrying out research work, with the objective of characterizing the effect of cavitation on the combustion process and the need to use a biofuel as an inhibitor solution on the cavitation phenomenon and as a means of energy transition.

The Research Progress of Melanin

2011 ◽  
Vol 204-210 ◽  
pp. 2057-2060
Author(s):  
Jian Ming Wang ◽  
Ai Hua Ao ◽  
Chang Sheng Qiao ◽  
Yu Zhong ◽  
Yuan Yuan Zhang
Keyword(s):  
High Speed ◽  
High Performance ◽  
Analytical Techniques ◽  
Research Progress ◽  
Countercurrent Chromatography ◽  
New Techniques ◽  
Wide Range ◽  
High Performance Capillary Electrophoresis ◽  
Relationship Of ◽  
The Relationship

The sources of melanin and the sorts of melanin are introduced. New techniques for extraction and analysis of natural melanin were introduced. New analytical techniques are high performance liquid chromatography, high-speed countercurrent chromatography, high performance capillary electrophoresis and chromatography-mass spectrometry. The relationship of polyketide melanogenesis molecular biology to that of nonmelanin-producing pathways in a wide range of fungi and other organisms is discussed. The applications of melanin are introduced.

Measurement of Wet cornering Traction of Tires

1971 ◽  
Vol 44 (4) ◽  
pp. 962-995 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Elastohydrodynamic Lubrication ◽  
Speed Test ◽  
High Speeds ◽  
Wide Range ◽  
Low Speeds ◽  
Test Variability ◽  
Traction Testing ◽  
Tread Rubber

Abstract We have shown that the cornering wet traction performance of tires, as measured with a special cornering trailer, is influenced by a number of factors and their interaction with each other. Unlike conventional low speed “spin-out” wet cornering traction testing, we have evaluated tire traction over the range 30–60 mph. Over this range there is a marked speed dependence in the rating of various tread rubbers and tread patterns. In general, tread rubbers show a wide range of performance ratings at the lower speeds (30–35 mph) and a narrower range at high speeds (55–60 mph). Various tread patterns on the contrary show similar behavior at low speeds but a wide divergence in traction level at high speeds. Higher durometer tread compounds show improved high speed traction for any given rubber. Tread hardness cannot be used as an omnibus indicator of wet traction performance, however, as each rubber has its own separate correlation line. Low coefficient pavement can have either low or high degrees of macrotexture, but the lack of microtexture or harshness (asperities in the fraction of a millimeter range) produces this type of pavement. Tires must perform safely on such pavement sections of public highways and the testing reported here was done on such test surfaces. Evaluations of four types of tread rubber show that they rank from high to low traction level in the order: SBR, Butyl, NR and BR (solution type) on smooth, low microtexture surfaces. Although BR gives low traction when used alone it is not so used in commercial tread compounds. When properly blended with SBR or NR, tread compounds containing BR give satisfactory traction performance and improved wear performance. The overall behavior of tires can be explained in terms of the concepts of hydrodynamic and boundary layer lubrication. At low speeds boundary layer lubrication predominates on all but the smoothest pavements. This accounts for the marked influence of tread rubber at low speeds. At high speeds both thick and thin film elastohydrodynamic lubrication predominate. In this speed range tread materials play a lesser role and tread pattern or geometry plays a larger role. The relative softness and deformability of tread compound, compared to pavement aggregate, accounts for the importance of elastohydrodynamic lubrication. Drawing on the work of many previous investigators and the data of this work it is postulated that the fraction of the tire contact area of a cornering tire that is in the elastohydrodynamic mode of lubrication is a linear function of speed. This accounts for the good linearity of the plots of traction as a function of speed. Test variability is discussed and steps taken to measure and control such relevant factors as water depth are outlined. The use of statistically designed testing programs with their inherent averaging character are advocated for those doing this work. In addition to their power at averaging test results, such designs uncover the strong interaction between tire and test variables that underlie all wet traction testing.

scholarly journals Performance Analysis of High Speed Hybrid CMOS Full Adder Circuits for Low Voltage VLSI Design

VLSI Design ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Subodh Wairya ◽  
Rajendra Kumar Nagaria ◽  
Sudarshan Tiwari
Keyword(s):  
High Speed ◽  
High Performance ◽  
Low Voltage ◽  
Supply Voltage ◽  
Vlsi Design ◽  
Reducing Power ◽  
Full Adder ◽  
Process Models ◽  
Majority Function ◽  
Simulation Results

This paper presents a comparative study of high-speed and low-voltage full adder circuits. Our approach is based on hybrid design full adder circuits combined in a single unit. A high performance adder cell using an XOR-XNOR (3T) design style is discussed. This paper also discusses a high-speed conventional full adder design combined with MOSCAP Majority function circuit in one unit to implement a hybrid full adder circuit. Moreover, it presents low-power Majority-function-based 1-bit full addersthat use MOS capacitors (MOSCAP) in its structure. This technique helps in reducing power consumption, propagation delay, and area of digital circuits while maintaining low complexity of logic design. Simulation results illustrate the superiority of the designed adder circuits over the conventional CMOS, TG, and hybrid adder circuits in terms of power, delay, power delay product (PDP), and energy delay product (EDP). Postlayout simulation results illustrate the superiority of the newly designed majority adder circuits against the reported conventional adder circuits. The design is implemented on UMC 0.18 m process models in Cadence Virtuoso Schematic Composer at 1.8 V single-ended supply voltage, and simulations are carried out on Spectre S.

scholarly journals Implementation and Comparison of Radix-8 Booth Multiplier by using 32-bit Parallel prefix adders for High Speed Arithmetic Applications

2021 ◽  
Vol 12 (3) ◽  
pp. 5673-5683
Author(s):  
Barma Venkata RamaLakshmi Et. al.
Keyword(s):  
High Speed ◽  
High Performance ◽  
Digital Systems ◽  
High Demand ◽  
Major Drawback ◽  
Booth Multiplier ◽  
Computational Speed ◽  
Parallel Prefix ◽  
Simulation Results ◽  
Prefix Adders

This paper presents the implementation and design of  Radix-8 booth Multiplier using 32-bit parallel prefix adders. High performance processors have a high demand in the industrial market. For achieving high performance and to enhance the computational speed multiplier plays a key role in performance of digital system. But the major drawback is it consumes more power , area and delay. To enhance the performance and decrease the area consumption and delay there are many algorithms and techniques. In this paper we designed a radix-8 Booth Multiplier using two parallel prefix adders and compared them for best optimized multiplier. The number of parital products generation can be reduced by n/3 by using radix-8 in the multiplier encoding. To further reduce the additions we have used booth recoding mechanism .We have implemented the design using Kogge stone adder and Brent kung adder. We observed that by using parallel prefix adders reduces the delay further more which results in significant increase in speed of the digital systems. The simulation results are carried out on XILINX VIVADO software.

Sign in / Sign up

Export Citation Format

Share Document