Random vibrations in unmanned aerial vehicles, mathematical analysis and control methodology based on expectation and probability

Abstract

The analysis of the random vibrations that occur during the flight of the unmanned aerial vehicles is important, as these random vibrations have random characteristic properties and have the ability to decrease the endurance of such systems. The accuracy of data collected from sensors in the unmanned aerial vehicle system is important for the flight control system. The transferring of these data among different sensors such as inertial measurement unit, axis accelerometers, GPS or cameras is usually affected by many factors. One of the important factors is the random vibration, which is usually caused by aerodynamic excitation or air turbulence. The problem of random vibrations has been studied for a long time and explained in many text books. In this study, the author introduces a mathematical analysis for random vibrations that are independent of their sources by considering these vibrations as a random and non-stationary process and designs a control methodology based on expectations and probability theory to reduce the effect of these vibrations. The analysis used in this research is based on the assumptions of practical approximation techniques.

3D geometry‐based UAV to vehicle multiple‐input multiple‐output channel model incorporating Unmanned aerial vehicle heaving motion

“…We made the assumption that the moving scatterers are spread in a constant manner between two terminals. By taking that all the channel parameters are uniformly distributed around the terminal and can be defined as, with respect to [26], the z ‐axis directional forces parameters with the range of 0.5 mg ≤ F z ≤ 1.25 mg and −6 ≤ F z , e ≤ 2, the velocity parameter $$\left\Vert {\mathbf{v}}^{{S}_{n}^{i}}\right\Vert {\text{\~{\,}}}U\left(0,1\right)m/s$$, where U defines the uniform distribution $${\phi }_{v}^{{S}_{n}^{\text{Tx}}},{\phi }_{v}^{{S}_{n}^{\text{Rx}}}$$ and $${\theta }_{v}^{{S}_{n}^{\text{Tx}}},{\theta }_{v}^{{S}_{n}^{\text{Rx}}}$$are uniformly distributed over (− π , π ). In addition, the rotation of the UAV is distributed over ( π /2, π /2) with the mass of approximately m ∼ 5 kg and the distance between the transceivers is $$\left\Vert {\mathbf{D}}^{i}\left({t}_{0}\right)\right\Vert =200m$$.…”

“…l s (0) shows the length of the inspection tool when the UAV is in a free-flight mode, and l s (t) stands for the movement after the first touch. The derivation from [26] shows that small UAV types have a vibration shape that is very similar to sinusoidal. A sine oscillation is a type of periodic motion in which the displacement varies as a sine function over time.…”

“…We made the assumption that the moving scatterers are spread in a constant manner between two terminals. By taking that all the channel parameters are uniformly distributed around the terminal and can be defined as, with respect to [26], the z-axis directional forces parameters with the range of 0.5 mg ≤ F z ≤ 1.25 mg and…”

“…The derivation from [26] shows that small UAV types have a vibration shape that is very similar to sinusoidal. A sine oscillation is a type of periodic motion in which the displacement varies as a sine function over time.…”

A Novel UAV Air-to-Air Channel Model Incorporating the Effect of UAV Vibrations and Diffuse Scattering

“…The UAV rotation may be relevant for reflecting the influence of atmospheric turbulence and wind gusts. However, when considering the operations of propellers and engines, both the UAV and antennas may experience high-frequency repetitive movements [14]. This refers to oscillating or back-and-forth motions around an equilibrium position, rather than spinning motions.…”