This work deals with electromyography (EMG) signal processing for the diagnosis and therapy of different muscles. Because the correct muscle activity measurement of strongly noised EMG signals is the major hurdle in medical applications, a raw measured EMG signal should be cleaned of different factors like power network interference and ECG heartbeat. Unfortunately, there are no completed studies showing full multistage signal processing of EMG recordings. In this article, the authors propose an original algorithm to perform muscle activity measurements based on raw measurements. The effectiveness of the proposed algorithm for EMG signal measurement was validated by a portable EMG system developed as a part of the EU research project and EMG raw measurement sets. Examples of removing the parasitic interferences are presented for each stage of signal processing. Finally, it is shown that the proposed processing of EMG signals enables cleaning of the EMG signal with minimal loss of the diagnostic content.
The employment of input filters in modern DC–DC converters is mandatory in order to ensure EMC (Electro-Magnetic Compatibility), provide power electronics with decent voltage and minimize the converter influence on the power grid. The LC type input filters bring also a possibility of voltage and current oscillation that may occur in the system. This oscillation may rise to a certain level that affects system stability. A wide range of methods are employed in order to attenuate these oscillations and allow appropriate system transient response. In this paper, the sliding mode control (SMC) strategy is proposed to reduce the input LC filter voltage and current oscillation and allow DC (Direct Current) output voltage control for both resistive and constant power load. The proposed control algorithm is intended for use in railway, tram and trolleybus DC/DC converters. For the proposed scheme of control simulation, a model is developed using Simulink software. Furthermore, laboratory stand experiments are carried out to verify simulation results.
In this paper, the implementation of sliding mode control algorithms for the case of power grid current regulation in a T-type bidirectional inverter system connected via an LCL filter to the power grid is proposed and presented. A mathematical model of such a system has been proposed, which was then implemented in a simulation environment. The method of designing sliding controllers using the Lyapunov method to conduct a stability proof is presented. The article includes a comparative analysis of two sliding mode control algorithms: the classic one, which includes equivalent control, discontinuous part, and proportional reaching law, and the hybrid one, in which the discontinuous part and reaching law were modified.
The reduction or elimination of selected torque and current harmonics is widely used in multilevel inverter fed induction motor drives. A wide range of methods are employed to achieve this goal. Those modes of operation allow the avoidance of certain torque and current harmonics that may lead to disturbance and even mechanical and electrical resonance. In this paper, the selective harmonic elimination technique (SHE-PWM) is employed to reduce the chosen torque harmonics in a three-level NPC inverter-fed induction motor drive. The proposed method is compared with the synchronized carrier pulse width modulation technique (SCPWM). For both schemes of control simulation, a model is proposed using Simulink software. Furthermore, laboratory stand experiments are carried out to verify the correctness of torque harmonics formation.
This paper contains an example of a simulation implementation of sliding mode control algorithms for the problem of adjusting the linear position of a quadrotor. A mathematical model of the drone was proposed, which was then implemented in a simulation environment. The method of designing sliding mode controllers using the Lyapunov method in order to improve stability was presented. A cascade system based entirely on sliding mode control algorithms is introduced. The article ends with a comparative analysis of simulation test results of classical control systems and controllers based on sliding mode control.
Praca zawiera propozycję rozwiązania problemu obecności zaburzeń napięciowych w systemie mikrosieci przy wykorzystaniu odpowiedniego algorytmu sterowania w postaci nieprzełączającego dyskretnego ślizgowego regulatora prądu sieciowego. Zaprojektowany został model matematyczny filtra LCL, który stanowi element pośredni pomiędzy siecią energetyczną a falownikiem sieciowym. Na podstawie tego modelu opracowany został algorytm sterowania, którego działanie przetestowane zostało za pomocą zaawansowanego modelu symulacyjnego. W eksperymencie symulacyjnym uwzględniono postać zaburzenia napięciowego pomierzonego w warunkach rzeczywistych, w zakładzie przemysłowym. Zakończenie artykułu stanowi prezentacja uzyskanych wyników przeprowadzonych testów.