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Control Methods
Published in Michael Muhlmeyer, Shaurya Agarwal, Information Spread in a Social Media Age, 2021
Michael Muhlmeyer, Shaurya Agarwal
Examples and applications of control theory are everywhere around us in the form of robotics, navigation of rockets, aircraft autopilot systems, adaptive cruise control of automobiles, heating and cooling systems in buildings, and many more. The formal control theory is believed to have been started by James Maxwell in 1868 during the analysis of the centrifugal governor. A more layman's introduction and intuitive explanation of control theory, including the two main types — open-loop and closed-loop control — was discussed in the previous chapter. The field has been evolving since its inception, and the methods range from a relatively simple PID controller to the more sophisticated optimal control methods. Depending on the dynamical systems and control objective, a controller must be chosen and designed carefully to meet the requirements.
Approaches to geomorphology
Published in Richard J. Chorley, Stanley A. Schumm, David E. Sugden, Geomorphology, 2019
Richard J. Chorley, Stanley A. Schumm, David E. Sugden
The degree to which the internal state or the output of a system is adjusted to its input is a measure of system equilibrium. In very simple systems equilibrium is attained by the output responding in a purely passive manner (i.e. the discharge of water from a rock-floored lake varying with flow into the lake), but more often changes in the throughput have an effect upon the input by a process known as feedback. In 1884, the same year as the American geomorphologist W. M. Davis published his first tentative statement of the cycle of erosion, the French scientist Henri-Louis Le Chatelier stated the principle that a change undergone by any of the factors governing the equilibrium of a chemical thermodynamic system will result in a compensating change in that factor in the opposite sense to the original change, such that the effect of the change will be halted and absorbed. This principle, which we now term homeostasis, self-regulation, or negative feedback has long been known in a general sense in the physical and engineering sciences; indeed, James Watt used it in the construction of a centrifugal governor on his steam engine in the last decade of the eighteenth century. What is more important from our point of view is that, seven years before Le Chatelier, the American geomorphologist G. K. Gilbert had used the concept, termed by him grade, in the context of landform development (Plate 1).
Elements of a Classical Control System
Published in Thrishantha Nanayakkara, Ferat Sahin, Mo Jamshidi, Intelligent Control Systems with an Introduction to System of Systems Engineering, 2018
Thrishantha Nanayakkara, Ferat Sahin, Mo Jamshidi
We are living in an era where man has been able to design and implement precise control systems not only in factory applications, such as robotic welding, assembling, and painting, etc., but also in military and space applications such as antimissile guard systems, coordination and stabilizing the modules in the International Space Station, and robots that explore other planets in the solar system. The history of modern control systems dates back to the seventeenth century. One of the best-known engineering achievements is the centrifugal governor designed by James Watt in 1769 based on a suggestion made by his industrial partner, Mathew Boulton. Before J. C. Maxwell gave the first rigorous mathematical foundations of automatic control in 1868 [1], the mechanical feedback systems proposed by James Watt contributed to the industrial revolution. We have to keep in mind that these developments took place when there were no digital computers. However, the early control engineers had carefully accounted for the essential features of a dynamical system before devising a control system to keep the dynamic system on track. With the advent of digital computers, the theoretical basis and the range of applications of control systems has witnessed dramatic improvements in the past few decades [2,3]. Figure 2.1 shows the concept of the centrifugal governor. Let us discuss the elements of a classical controller using Figure 2.1.
Performance and emission characteristics of diesel engine using biodiesel with the effect of Dimethyl carbonate (DMC) fumigation
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
The layout of the test engine setup is shown in Figure 1. A naturally aspirated, water-cooled, Kirloskar – diesel engine was used for the experiments, and the test engine specifications are listed in Table 1. The engine was modified for injecting dimethyl carbonate (DMC) through electronically controlled fuel injector, into the air intake to the cylinder. The DMC injection pressure was about 3bar and the amount of DMC injected was controlled by the electronic control unit. The engine is coupled with an electrical dynamometer and fitted with a conventional fuel injection system, which has a three-hole nozzle of 0.2 mm. The nozzle opening pressure recommended by the manufacturer was 200bar and the injection timing is 23°bTDC. The centrifugal governor, which is fitted on the engine, enables the automatic regulation of the engine speed. The injection system of the engine was periodically cleaned and calibrated as recommended by the manufacturer. A K-type thermocouple-based temperature sensor was used to measure the exhaust gas temperature. The emission concentrations of HC and CO, CO2and NOx were measured with AVL 444 DI gas analyzer. The diesel smoke was measured by AVL smoke meter (AVL-437).