This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
In this work, a hybrid control strategy integrating proportional derivative and H-infinity control method is proposed for a serial two-link robotic manipulator. The aim of this research is to achieve an improved trajectory tracking performance of the robot arm. The H-infinity controller achieves high performance and robustness in the presence of disturbances and uncertainties, such as unwanted overreaction caused by the derivative control's quick response times, while the proportional derivative controller stabilizes the nonlinear manipulator system. Simulation results using matlab shows that, the proposed hybrid controller, which integrates the advantages of both proportional derivative and H-infinity controllers, has the lowest rise time for the second link, the lowest settling time for the two links, the lowest peak time for both links and the fastest decay of the error response. In addition, the hybrid control scheme also has the lowest mean square error value, with 53.3% improvement over H-infinity controller and 91.8% improvement over proportional derivative controller, indicating improved trajectory tracking performance when compared to pure proportional derivative and pure H-infinity controllers, respectively. It was also discovered that, the hybrid controller has the lowest Integral Absolute Error (IAE), Integral Square Error (ISE), Integral Time Absolute error (ITAE) and Integral Time Square (ITSE) for the second link, while the error values for the first link are fairly okay, showing the superior performance of the hybrid controller above PD and H-infinity controllers respectively.
This study examines the effects of perturbations on the digital terrestrial television broadcasting (DTTB) signal in Jos, Plateau State, Nigeria, using measurement-based performance analysis. In order to examine the effects of environmental perturbations on DTTB signal, measurement campaign used the Nigerian Television Authority, Integrated Television Services (ITS) digital video broadcasting -second generation (DVB-T2) signal. The aim of the research was to identify the environmental and atmospheric perturbations with highest impact on DTTB signal. Field measurement was accurately obtained throughout the measurement campaign using the E8000 series spectrum analyzer, a DVB-T2 receiver, and other facilities in order to actualize the two important measurement characteristics, such as field strength and received signal strength (RSS). The outcome showed a significant amount of dips in route A, depriving towns surrounding rocky hills of a DVB-T2 signal, as demonstrated in the Du community with RSS values of -87.1 dBm, 85.2 dB , and -27.8 dB V/m, -23.9 dB V/m for field strength. Additionally, the results show that signal performance was better in the dry season compared to the rainy season (more primary coverage in the dry season compared to the rainy season), with the RSS value being -41.6 dBm versus -36.4 dBm and the field strength value being 34 dB/m versus 38.6 dB/m for route A, or the same on route B. Solving signal propagation issues requires understanding the fundamental metrics driving an increase in perturbations in any broadcast environment. Creating a model to address these issues will help with system evaluation, network planning, and broadcast service operation, ensuring quality of service (QoS).
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
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