Abstract. The optimal location of piezo-actuators and piezo-sensors for the vibration control of a rectangular plate with SFSF (Simply Supported -Free -Simply Supported -Free) boundary conditions is presented in the paper. Based on bending moments, M x(x, y) and My(x, y), the modal control forces generated by the piezo-stripes are calculated for the first five mode shapes. Calculations are carried out for different locations of two piezo-strips directed along the X and Y axes. The obtained results are used to define performance indexes of modal control forces for the two considered directions of vibration. In a similar way the modal unit elongations of the piezo-sensors are calculated for two different orientations of the piezos on the plate. Based on these results the objective cost functions J ε-odd and Jε-even are defined separately for odd and even modes. The quasi-optimal locations of the piezo-actuators and piezo-sensors are determined by maximizing the proposed cost functions. After analytical and numerical investigations the process of the full model identification is carried out at the laboratory stand. A chirp signal is applied in the identification process. The rectangular plate is excited with the chirp force while output signals are measured by the piezo-sensors oriented in the perpendicular directions X and Y . In such a way two mathematical models are obtained to control the vibration of the plate separately for odd and even natural modes.
Abstract:The paper presents the process of modeling and designing control laws for four-rotor type of the Parrot UAV. The state space model is obtained by using several phenomena like gyroscopic effects for rigid bodies, propellers and rotors. The obtained model has been used to design PID control laws for roll, pitch, yaw angle and altitude, respectively. The numerical simulations of the closed loop model are shown that system in satisfy way stabilize flight of the quadro-rotor in all considered directions.
Energy harvesting from moving structures for autonomous electrically powered applications, i.e. unmanned aerial vehicles (UAVs), especially in the case quadrotors, has been a common subject of scientific investigations in last years. Most of them have looked into improving the endurance of electrically powered UAVs using technologies such as photovoltaic or vibration harvesting. UAV platforms have a limited amount of power for electrical suppling. In order to keep a constant time of flight duration, the UAV can be equipped with an additional battery, which increases the total mass and causes higher energy losses. Therefore, we address this problem in our paper by proposing a vibration-based energy harvesting system. It consists of piezoelectric harvesters integrated into a frame of BLDC rotors. In order to check efficiency of the energy harvesting system, the copter is equipped with MFC harvesters. Taking into account this solution, the distributedparameters of the electromechanical system in the modal coordinates are estimated using numerical methods. The simulation results showedhow the duty cycle of the PWM signal applied to the BLDC rotor and resistive load connected to the system influence on voltage generating by the piezo harvester, while experimental test allow verify them.
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