...but we will here use the more familiar notation . By writing the derivate as , so that we include the time argument, we are emphasizing that the value of the derivative may change with time. Because it is typically cumbersome to repeatedly write down the argument, we can also write the derivative as just , while remembering that its value may change with time. A differential equation is an equation that relates the time derivative of a variable to its level. An example is the equation (1) . The variable is called a state variable because it gives the state of the system at any given point in time. In our example, gives the state or level of per capita capital stock. 2. A Dynamic System The basic dynamic principle is the idea that “the way things are determines the way things change.” A differential equation is one way of modeling the basic dynamic principle. The state variable indicates the way things are, while the time derivative indicates how things change. The differential equation itself is what relates the two. More precisely, a differential equation typically presents a functional relationship, showing how depends upon . When we want to...
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...through a system is defined as The Steady Flow Energy Equation (SFEE). The term ‘Fluid’ is defined as a substance that can flow. There are two types of fluids, gases and liquids. A Steady flow process occurs when the state of fluid conditions at any point in the control volume remain constant with respect to time. Specifically, the mass flow rate entering the system is equal to the mass flow rate exiting the system. Conversely, non-uniform flow process is when the velocity varies at any instant. The common systems which involve steady flow processes are open system turbines, compressors, pumps etc. [1] (W.BOLTON, 1990) Background Theory Steady flow energy equation The development of the Steady Flow Energy Equation of fluid is derived from the principle of conservation of energy which state that: For any mass system, the net energy supplied to the system equals the increase of energy of the system plus the energy leaving the system. Therefore, if is the increase of energy of the system, is the energy supplied to the system and the energy leaving the system. Therefore, the energy balance for the system is considered. The energy of a mass of fluid contains the forms as followed: 1. Internal energy due to the activity of the molecules of the fluid forming the mass; 2. Kinetic energy due to the velocity of the mass of fluid itself; 3. Potential energy due to the mass of fluid being at a height above the datum level and acted upon by gravity. [2] As steady flow...
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...Torsional Mechanical System | Name: Elina Ioannou P12201589 Lecturer: Prof. Bogumil Ulanicki | De Montfort University 2/24/2015 | ContentsPage Introduction………………………………………………………………………………….3 Parameters of the open loop 1DoF torsional system…………………….4 Position Proportional Control plotting data………………………………….6 Parameters of transient responses and their affect by gain Kp……..11 Position Proportional control with velocity feedback plotting data.15 Parameter of transient responses and their affect by gain Kd……….20 Speed Proportional feedback control……………………………………………23 The response of closed loop system due to increase of Kp values…24 Derivation of Closed loop system transfer function (fig. 2.2.2)………25 Changes of the location of poles due to changes of Kp and Kd Values……………………………………………………………………………………………25 Conclusion……………………………………………………………………………………..28 References……………………………………………………………………………………..29 Introduction All rotating machinery systems experience torsional oscillations to some degree during start up, shut down and continuous operation. Consequently, the evaluation and analysis of the torsional response characteristics of rotating and reciprocating equipment represent the reliability of a system. The Control and Dynamics Laboratory 1 was carried out to measure and investigate the dynamic characteristics of a simple single degree-of-freedom torsional mechanical system with the support of...
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...ϭ ᎏᎏ R and k var T ϭ ᎏᎏ R2 Birth–Death Processes For a birth-death process, the steady-state probability (pj) or fraction of the time that the process spends in state j can be found from the following flow balance equations: ( j ϭ 0) ( j ϭ 1) ( j ϭ 2) и и и ( jth equation) p0l0 ϭ p1m1 (l1 ϩ m1)p1 ϭ l0p0 ϩ m2p2 (l2 ϩ m2)p2 ϭ l1p1 ϩ m3p3 (lj ϩ mj)pj ϭ ljϪ1pjϪ1 ϩ mjϩ1pjϩ1 The jth flow balance equation states that the expected number of transitions per unit time out of state j ϭ (expected number of transitions per unit time into state j). The solution to the balance equations is found from l0l1 и и и ljϪ1 pj ϭ p0 ᎏᎏ m1m2 и и и mj ( j ϭ 1, 2, . . .) and the fact that p0 ϩ p1 ϩ и и и ϭ 1. Notation for Characteristics of Queuing Systems pj L Lq Ls W Wq Ws l m ϭ ϭ ϭ ϭ ϭ ϭ ϭ ϭ ϭ steady-state probability that j customers are in system expected number of customers in system expected number of customers in line (queue) expected number of customers in service expected time a customer spends in system expected time a customer spends waiting in line expected time a customer spends in service average number of customers per unit time average number of service completions per unit time (service rate) l r ϭ ᎏᎏ ϭ traffic intensity sm 1136 CHAPTER 2 0 Queuing Theory The M/M/1/GD/∞/∞ Model If r Ն 1, no steady state exists. For r Ͻ 1, pj ϭ r j (1 Ϫ r) ( j ϭ 0, 1, 2, . . .) l L ϭ ᎏᎏ mϪl l2 Lq ϭ ᎏᎏ ...
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...fundamentals of feedback control. This was done by following the rhetoric laid out in the DC-4 manual, which included using speed controller of an electric motor as well as a proportional controls and PI controls, based on the steady state error. By definition a feedback control system includes a number of components that has their output signal modified by a controller who supplies the input signal. Gain is a very important property of a feedback control system if not the most important. Gain by definition is the measurement of the ability to increase the amplitude or power of a signal from input to output on a two port circuit which can simply be stated as the correction for an amount of error. The error corrected is increased as gain is increased as can be seen in Equation 1 listed below. For the variables the ess term is error in steady state, Yr is the reference speed, kp is the control gain, and G is calibration gain....
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...Yqk86@yahoo.com.cn Abstract- In order to improve the performance of LMS (Least Mean Square) adaptive filtering algorithm, an improved robustness adaptive step-size LMS equalization algorithm was presented by establishing a nonlinear relationship between the two relevant statistics for step-size factor μ ( n ) and the error signal e( n ) . Compared with other algorithms, this algorithm overcomes of sensitivity to the noise coming from outside by introducing the statistics for the correlation of error signal e( n ) . Meanwhile, this algorithm presents some improvement on the principle of robustness. Theoretical analysis and simulation results indicate that this algorithm has a faster convergence speed and a better steady-state error, and can go back to steady state quickly when the channel is varying with time, which shows a better robustness and convergence than other traditional ones. Key words- adaptive equalize; variable step-size; Robustness; least mean square; error signal I. INTRODUCTION Adaptive equalization technology has always being an important technical topic in wireless mobile communication, which has an important significance to solve the inter-symbol interference (ISI) brought by multipath effect and channel’s finite bandwidth Among the numerous equalization algorithm, least mean square error algorithm (LMS) has attracted a wide spread attention due to its simple...
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...CENTRAL TYRE INFLATION SYSTEM (CTIS) • CTIS SYSTEM IS A MECHANICAL SYSTEM THAT ALLOWS DRIVER TO ADJUST VEHICLE’S TYRE PRESSURE WHILE THE VEHICLE IS IN MOTION i.e. BY INFLATING AND DEFLECTING THE TYRE PRESSURE. •USING CTIS A VEHICLE CAN BE OPERATED WITH TYRE PRESSURE APPROPRIATE TO THE SPEED AND STRENGTH OF THE ROAD SECTION BEING NEGOTIATED AND THE LOAD BEING CARRIED WITH INCREASED VEHICLE MOBILITY. This system is used to inflate/deflate tyres in order to adapt the vehicle's rolling capabilities to terrain conditions, in accordance with several pre-set categories: EMERGENCY, SOFT GROUND, TRACK and HIGHWAY. This function is controlled from the driving position by a special instrument panel •which activates a logic box to inflate/deflate the tyres, sending compressed air to the wheels via a rotary joint on the hub reducer of each wheel. • •MAJOR COMPONENETS IN THE SYSTEM •OCP (OPREATOR CONTROL PANEL) •PCU (PRESSUE CONTROL UNIT) •CTIS VALVES Central tyre inflation system (CTIS) vehicle Know your User Instruction Centralized tyre inflation Central tyre inflation system (CTIS) vehicle Press ON/OFF button to switch the device ON Know your At power up of system, the empty load signal will first fast blinking and will steady on when ECU is correctly initialized. If Load signal continuously blinks, the ECU initialization fails. The process initialization starts by blinking successively all panel signals (auto-test). After the initialization sequence...
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...ABSTRACT The objective of the controls laboratory is to use multiple methods to characterize parameters of a DC motor and compare these experimental methods to theory. By determining system parameters accurately, closed loop control can be used to optimize systems not only involving DC motors but essentially any mechanical system. Gains for several controllers were calculated and the effect of adding mass to the flywheel of the motor was investigated. Initially, the dead-zone and saturation voltages were obtained for the motor, to define the operating range. To determine system parameters (namely the time constant Tm and motor gain Km) two methods were investigated: step voltage response and frequency response. Using the step response, the steady-state speed of the DC motor was recorded for incremented input voltages and plotted. The slope of the linear regression of this plot is an estimation of the motor gain. The plot can be found at the end of this abstract. Additionally, for each input voltage a characteristic speed was determined by taking the product of the steady-state speed ωss and (1-e-1). Since the time constant is defined as the time taken for the exponent to be negative one (i.e. e-1), the characteristic speed occurs at the time constant. The time constant was obtained for each input voltage and averaged. To determine these parameters using frequency response, the input voltage was incremented over a range of frequencies. For each input frequency, the amplitude...
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...secondary value is substantially proportional to the primary value. Much development by various manufacturers has been done to improve the output measurements. The appearance and development of the Optical Current Transformer (OCT) in the last few decades become much more interesting to replace the conventional CT in the power system operation. In the past 15 years, Optical CT has received a significant attention by a manufaturer to replace iron-core CT in electric power industry. This Optical CT is non conductive and lightweight which can give the end user easiness of installing and doing maintenance. 2. Literature Review In [1], the author describes the experimental comparison between conventional current transformer (CT) and the optical current transformer (OCT) especially in steady state response, transient response and impact of ambient temperature. Optical CT offered high accuracy in measuring the primary current for measuring or protection purposes compared to a conventional CT. Most of the studies regarding the Otpical CT lately are raised in order to demonstrate the advantages of the Optical CT in power system compared to conventional CT. In reality, this optical CT has been installed together with Magnetic CT to compare the effectiveness and the accuracy of the Optical CT with Magnetic CT. In [2], thermal modeling of CT for Top Oil Temperature (TOT) and Hot Spot Temperature (HST) was developed to analyze the behaviour of the oil-filled...
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...management is about enabling staff to use qualities in order to fulfill their role and contribute to the organization’s mission and purpose. Good human resource is essential if organizations want to attract and retain good staff. If people see that an organization values its staff, they are more likely to apply for a job with the organization and more likely to stay once they are recruited. Good human resource management means that an organization reduces risk to its staff and reputation. It can do this by considering issues such as employment can also reduce cost for an organization. For example, good recruitment policies and processes mean that organizations can efficiently recruit people who will carry out their jobs effectively. Good systems for performance management mean that organizations can ensure that they are getting the best from their staff. It should be noted that volunteers are an important resource for many organizations. HUMAN RESOURCE MODELS Manpower Models Manpower requirements models are designed to tell the human resource planner how many of what types of people are needed to produce given levels of output....
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...Control system of a DC motor based on PID algorithm using MATLAB SIMULINK DC motors have variable characteristics and are used extensively in variable-speed drives. DC motor can provide a high starting torque and it is also possible to obtain speed control over wide range. Why do we need a speed motor controller? For example, if we have a DC motor in a robot and we just apply a constant power to each motor on a robot, then the poor robot will never be able to maintain a steady speed. It will go slower over carpet, faster over smooth flooring, slower up hill, faster downhill, etc. So, it is important to make a controller to control the speed of DC motor in desired manner. And that’s why we are now interested to design a control system named PID. Now if we want to define the PID control system,then it will be like this A block diagram of PID Control system Now if we want to discuss about the algorithm behind this control system then,it constritutes of three basic part all comes from the following equation: The Characteristics of P, I, and D Controllers A proportional controller ( ) will have the effect of reducing the rise time and will reduce but never eliminate the steady-state error. An integral control ( ) will have the effect of eliminating the steady-state error for a constant or step input, but it may make the transient response slower. A derivative control ( ) will have the effect of increasing the stability of the system, reducing...
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...methods for studying the evolution of stars, ocean currents, weather patterns, plate tectonics and even blood circulation. Some important technological applications of fluid dynamics include rocket engines, wind turbines, oil pipelines and air conditioning systems. FLOW The movement of liquids and gases is generally referred to as "flow," a concept that describes how fluids behave and how they interact with their surrounding environment — for example, water moving through a channel or pipe, or over a surface. Flow can be either steady or unsteady. In his lecture notes, "Lectures in Elementary Fluid Dynamics" (University of Kentucky, 2009) J. M. McDonough, a professor of engineering at the University of Kentucky, writes, "If all properties of a flow are independent of time, then the flow is steady; otherwise, it is unsteady." That is, steady flows do not change over time. An example of steady flow would be water flowing through a pipe at a constant rate. On the other hand, a flood or water pouring from an old-fashioned hand pump are examples of unsteady flow. Flow can also be either laminar or turbulent. Laminar flows are smoother, while turbulent flows are more chaotic. One important factor in determining the state of a fluid’s flow is its viscosity, or thickness, where...
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...Approximately 14 billion years ago, the universe that stands today was born. There are various explanations for how it was created. Research shows that they are essential scientific questions and it stimulate scientists to debate their research. Many scientists from all over the world and different time periods work to find the reason behind its creation. The different theories on the origin of the universe have a great impact on the way humans view how the universe was created. The most known is the Big Bang theory and smaller theories include the String theory, the Incredible Bulk theory, the Times Arrow theory and the Steady State theory. (Tate) The universe is almost 14 billion years old. There are two common ways scientists use to calculate how old the universe is. The first method involves measuring the speeds and distances of the galaxies. Scientists interpret that the galaxies were closer together before in the past because all of them are slowly moving further from each other every second. Identifying the current speeds and distances of the galaxies, included with the rate at which the universe is accelerating, permits scientists to calculate how long it took...
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...C H A P T E R 4 THE ECONOMY IN THE VERY LONG RUN: The Economics of Growth LEARNING OBJECTIVES After reading and studying this chapter, you should be able to: ̈ Understand that economic growth is due to growth in inputs, such as capital and labour, and to improvements in technology. ̈ Understand that capital accumulates through savings and investment. ̈ Understand that the long run level of output per person depends positively on the savings rate and negatively on the rate of population growth. ̈ Understand that the basic economic growth model predicts that standards of living in different countries will eventually converge. 61 62 PART 2 The Economy in the Long Run and the Very Long Run e have enormously higher incomes than did our great-grandparents. People in industrialized nations are far wealthier than people living in less developed countries. In fact, North Americans and many Europeans had higher incomes a century ago than people in poor countries do today. What accounts for these vast differences? What will determine our standard of living in the future? Growth accounting and growth theory answer these questions. Growth accounting explains what part of growth in total output is due to growth in different factors of production (capital, labour, etc.). Growth theory helps us understand how economic decisions control the accumulation of factors of production, for example, how the rate of saving...
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...Senior Member, IEEE Abstract—The first five-phase induction motor drive system was proposed in the late 1970s for adjustable speed drive applications. Since then, a considerable research effort has been in place to develop commercially feasible multiphase drive systems. Since the three-phase supply is available from the grid, there is a need to develop a static phase transformation system to obtain a multiphase supply from the available three-phase supply. Thus, this paper proposes a novel transformer connection scheme to convert the threephase grid supply to a five-phase fixed voltage and fixed frequency supply. The proposed transformer connection outputs five phases and, thus, can be used in applications requiring a five-phase supply. Currently, the five-phase motor drive is a commercially viable solution. The five-phase transmission system can be investigated further as an efficient solution for bulk power transfer. The connection scheme is elaborated by using the simulation and experimental approach to prove the viability of the implementation. The geometry of the fabricated transformer is elaborated in this paper. Index Terms—Five phase, multiphase, three phase, transformer, turn ratio. I. INTRODUCTION ULTIPHASE (more than three phase) systems are the focus of research recently due to their inherent advantages compared to their three-phase counterparts. The applicability of multiphase systems is explored in electric power generation [2]–[8], transmission [9]–[15]...
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