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Quadcopter control using the viscoelastic control law
Manas Kumar Sahoo,J. K. Dutt,S. K. Saha 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10
Quadcopter is an unmanned aerial vehicle (UAV) with four rotors and generally, they are placed in a square formation with equal distance from the centre of mass. The thrust produced by each rotor is directed upward and the UAV is controlled by varying the magnitude and direction of the rotor speed with the help of DC motors. In this paper, a novel controller is proposed that imitate the behavior of four-element viscoelastic material. Some unmodelled disturbances was fed to the system to check the controller performance. The FE controller performance was compared with the classical PID controller. As in real world performances quadcopters are used in the presence of various sensors and other measuring devices, the time delay introduced by these instruments becomes very important for the stability of the system. Hence both the controllers were subjected to some designed time delay so that they can be compared in real-world scenario. The simulation of the above was carried out with the help of Simulink platform and from the simulation it was found that the FE controller is fast, accurate and precise in performance compared to the PID controller.
Numerical analysis of the effect of tool wear on surface integrity during hard turning
Rupak Kumar Nayak,Gaurav Bartarya,Manas Ranjan Sahoo 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3
The white layer formed during hard turning deteriorates surface integrity, thereby severely affecting the fatigue life of machined parts. A 2D FEM-based simulation model has been developed to simulate cutting temperature profiles in workpieces for the prediction of white layer thickness developed below the machined surface. Machining was simulated for fresh and worn tools with predefined flank wear. The temperature profile generated in the workpiece was analyzed for the critical temperature for phase transformation leading to white layer formation. The critical temperature was found to be deeper in the subsurface with an increase in cutting speed and wear, indicating a thicker subsurface white layer. Experimental observations using fresh tools were found very close to the simulation results. The model was extended to simulate temperature profile and predict the white layer for machining with tools having predefined tool flank wear.
Unusual Uptake of Prostate Specific Tracer <sup>68</sup>Ga-PSMA-HBED-CC in a Benign Thyroid Nodule
Damle, Nishikant Avinash,Tripathi, Madhavi,Chakraborty, Partha Sarathi,Sahoo, Manas Kumar,Bal, Chandrasekhar,Aggarwal, Shipra,Arora, Geetanjali,Kumar, Praveen,Kumar, Rajeev,Gupta, Ravikant The Korea Society of Nuclear Medicine 2016 핵의학 분자영상 Vol.50 No.4
$^{68}Ga$-Prostate specific membrane antigen- N,N′-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N′-diacetic acid- positron emission tomography/computed tomography or 68 Ga- HBED-CC-PSMA PET/CT, popularly known as PSMA PET/CT, is able to detect a small volume of recurrent prostate carcinoma (PC) when there is a prostate specific antigen (PSA) rise on follow-up after prostatectomy or other definitive treatment for PC. The use of PSMA PET/CT in the initial staging in PC is uncertain at this time. Clinical studies are underway to define its exact role in the management of the disease. At the same time it is important to be aware of unexpected sites of uptake of this ligand. We present here the case of a 62-year-old male patient who underwent prostatectomy for adenocarcinoma prostate. He also had a long-standing left solitary thyroid nodule (STN). Four months after surgery, he had a rising trend in serum PSA levels on three occasions, but the absolute value was less than 4 at all times. He underwent a $^{68}Ga$-PSMA-HBED-CC PET/CT, but it did not reveal any recurrent/metastatic site of disease. However, there was increased tracer uptake in the left STN. Fine needle aspiration cytology revealed features of atypia of undetermined significance, Bethesda category III. The patient underwent a left hemithyroidectomy and the histopathology showed features of a follicular adenoma.