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Abstract

The aim of this study is to design a control strategy for the angular rate (speed) of a DC motor by varying the terminal voltage. This paper describes various designs for the control of direct current (DC) motors. We derive a transfer function for the system and connect it to a controller as feedback, taking the applied voltage as the system input and the angular velocity as the output. Different strategies combining proportional, integral, and derivative controllers along with phase lag compensators and lead integral compensators are investigated alongside the linear quadratic regulator. For each controller transfer function, the step response, root locus, and Bode plot are analysed to ascertain the behaviour of the system, and the results are compared to identify the optimal strategy. It is found that the linear quadratic controller provides the best overall performance in terms of steady-state error, response time, and system stability. The purpose of the study that took place was to design the most appropriate controller for the steadiness of DC motors. Throughout this study, analytical means like tuning methods, loop control, and stability criteria were adopted. The reason for this was to suffice the preconditions and obligations. Furthermore, for the sake of verifying the legitimacy of the controller results, modelling by MATLAB and Simulink was practiced on every controller.
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Abstract

Two low-cost methods of estimating the road surface condition are presented in the paper, the first one based on the use of accelerometers and the other on the analysis of images acquired from cameras installed in a vehicle. In the first method, miniature positioning and accelerometer sensors are used for evaluation of the road surface roughness. The device designed for installation in vehicles is composed of a GPS receiver and a multi-axis accelerometer. The measurement data were collected from recorded ride sessions taken place on diversified road surface roughness conditions and at varied vehicle speeds on each of examined road sections. The data were gathered for various vehicle body types and afterwards successful attempts were made in constructing the road surface classification employing the created algorithm. In turn, in the video method, a set of algorithms processing images from a depth camera and RGB cameras were created. A representative sample of the material to be analysed was obtained and a neural network model for classification of road defects was trained. The research has shown high effectiveness of applying the digital image processing to rejection of images of undamaged surface, exceeding 80%. Average effectiveness of identification of road defects amounted to 70%. The paper presents the methods of collecting and processing the data related to surface damage as well as the results of analyses and conclusions.
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Abstract

In renewable systems, there may be conditions that can be either network error or power transmission line and environmental conditions such as when the wind speed is unbalanced and the wind turbine is connected to the grid. In this case, the control system is not damaged and will remain stable in the power transmission system. Voltage stability studies on an independent wind turbine at fault time and after fixing the error is one of the topics that can strengthen the future of independent collections. At the time of the fault, the network current increases dramatically, resulting in a higher voltage drop. Hence the talk of fast voltage recovery during error and after fixing the error and protection of rotor and grid side converters against the fault current and also protection against rising DC voltage (which sharply increases during error) is highly regarded. So, several improvements have been made to the construction of a doubly-fed induction generator (DFIG) turbine such as: a) error detection system, b) DC link protection, c) crow bar circuit, d) block of the rotor and stator side converters, e) injecting reactive power during error, f) nonlinear control design for turbine blades, g) tuning and harmonization of controllers used to keep up the power quality and to stabilize the system output voltage in the power grid. First, the dynamic models of a wind turbine, gearbox, and DFIG are presented. Then the controllers are modeled. The results of the simulation have been validated in MATLAB/Simulink.
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