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This paper utilizes the quantitative feedback theory (QFT) to design a robust controller for adaptive cutting feedrate control. The proposed algorithm could dynamically change the feedrate according to the spindle current which is highly related to the measured cutting force. The QFT controller could provide the constant cutting force even under different cutting condition. Hence, the machining efficiency...
The input command shaping technique is integrated with computerized numerical control (CNC) interpolators to suppress structural vibration of machine tools. The algorithm is called integrating input-shaping interpolator (ISI) which applies the input shaping on the acceleration/deceleration stage before interpolation (ADBI) such that the command contour errors can be avoided. Theoretical derivation...
The long-term settlements over tunnels can be rather significant, particularly when tunnels are embedded in soft and compressible soils. The influence of grouting on the evolution of long-term surface settlement, as well as ground loss, is simulated by imposing prescribed volumetric strain on the disturbed area around the tunnel due to shield tunneling. The volumetric strain could be detected from...
Acceleration/deceleration (Acc/Dec) federate planning is used to generate smooth command in motion control. Typically, acceleration/deceleration before interpolation (ADBI) scheme is to plan the tangent direction velocity profile for the trajectory using a look-ahead function. However, the ADBI scheme could cause the axis velocity command's discontinuity at the line segments junction. Although the...
The effect of curing process on the warpage of encapsulated electronic package is considered by using a coupled chemical-thermo-mechanical modeling methodology. A cure-dependent constitutive model that consists of a cure kinetics model, a curing and chemical aging induced shrinkage model and a degree of cure-dependent viscoelastic relaxation model was implemented in a numerical finite element model...
The article instructs the work principle of the injector device and its application in the reverse-circulation sampling drilling bit. Then use the fluent fluid engineering emulator software to simulate the internal fluid territory of the injector when the obliquity is 15, 30,45,60,75 and 90 degree. The pressure distributing cloud chart and the corresponding numerical value has been gotten. An injector...
Fire on railway station is a very important disaster is worth of consideration. Fire risk evaluation is an important part for reducing and controlling fire in railway station. Up to now there are several evaluation methods, but few of them combining fire probability with fuzzy evaluation. Based on overall analysis of fire risk in railway station, a mathematical model of comprehensive probability fuzzy...
The main important factors to affect the evacuation of people by analyzing the fire theory happened in the underground space have been gotten. They are fire temperature, smoke concentration, and poisonous gas and ventilated velocity etc key factors. Do the emulation analysis about some kind of underground space fire by fire simulation software Smart-fire and the fire scene and situation have been...
Fire in the underground long and big tunnel is a serious accident. Itpsilas very essential to study the evacuation technology and rescue people in the fire situation. The authors do the theory research about the fire factors that affect the peoplepsilas lives in the tunnel, including high temperature, toxic gases, visibility and heat radiation and so on. Adopted the technical engineering risk theory,...
Fire on railway station is a very important disaster is worth of consideration. When fired, smoke will bring many pollution gases and harmful particles with high temperature. Study the smoke flow phenomenon will provide help for people's lives. In the article, the author use the Smartfire software to simulate the fire on the station, it has provide the critical ventilation velocity that will disturb...
Air drive reverse circulation bit interior fluid field analysis has relied on experiments for a long time. With the development of the computer, numerical simulation and emulation software brought many advantages contrasting the experiment. However, due to the complexity of the interior fluid field, few people have done the resolution calculation for it. In this article, through simplifying the air...
Fire in the underground space is a serious accident. It's very essential to study the evacuation technology and how to rescue people in the fire situation. There are about 4 kinds of evacuation style in long and bit tunnel after a fire, that is. The authors do the research about the fire evacuation technology based on risk theory. In the article, 5 grades fire risk grades have been made. that is:1...
An adaptive reference control (ARC) technique is proposed for minimizing overshoot/undershoot voltage and settling time of low-dropout regulators (LDO). Linear operation provided by ARC technique can dynamically and smoothly adjust the reference voltage for increasing slew rate of error amplifier and forcing output voltage back to its steady-state value rapidly. The amount of transient revision is...
This paper presents a BRC technique to speed up the charging time of the Li-Ion battery. Based on the physical properties of the battery cell, the charger circuit charges the cell with three stages, which are trickle current (TC), constant current (CC), and constant voltage (CV) stages. Due to the internal parasitic resistance of the Li-Ion battery pack system, the charger circuit switches from the...
This paper proposes a fast transient technique (FTT) to achieve excellent transient response of current-mode buck DC-DC converters. The proposed technique combines a non-linear control and a linear control mechanism to achieve fast transient response time, low output ripples, and stable transient operation at the same time. The test chip was fabricated in UMC 0.18-mum process. Experimental results...
In this paper, the compensation of internal resistance of the Li-Ion battery is proposed. The requirement of fast and steady charger becomes the most important issue for power management ICs. Refer to the characteristics of the battery, how to charge the battery with adequate current and fasten the time of charging is critical to the devisers. Due to the impedance of battery pack, the energy of charger...
A programmable dual hysteretic window comparator is presented in this paper. The comparator uses a cascoded flipped voltage follower (CASFVF), a high speed V-I converter, and a current comparator to enhance the response time and accuracy. Moreover, the positive and negative hysteretic thresholds can be programmable, respectively. Simulation results in 0.25-mum CMOS technology demonstrate the validity...
A programmable voltage-to-current converter with linear voltage control resistor (VCR) is presented in this paper. It uses a cascoded flipped voltage follower (CASFVF) to be the input stage in order to enhance the response time and accuracy. Programmability is achieved by using the control signal Vctrl to adjust the equivalent resistance of VCR. Simulation results in 0.25-mum CMOS technology demonstrate...
We have developed a switched-capacitor CMOS voltage reference (SCVR). The circuit is shown in Fig. 24.3.2 and is composed of a low-power bias circuit [G. De Vita and G. iannacone, 2007], a core circuit and a switched-capacitor difference amplifier that is insensitive to op-amp offset voltage. The clock signals (phi1, phi2, phi2') are non-overlapping to prevent leakage. The core circuit supplies Vgs1...
An adaptive frequency control (AFC) technique is proposed for minimizing transient dropout voltage and response time of switching DC-DC converters. As we know, nonlinear fast- transient techniques with fixed switching frequency can effectively regulate the unstable output voltage back to steady-state within a short time. However, they suffer from oscillation problem because of large sourcing or sinking...
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