Numerical analysis of the support platform for an unmanned aerial vehicle

The study investigates a thin-walled support platform for an unmanned aerial vehicle, i.e. aluminum beams connected by flat bars and angle irons. The construction is a kind of frame for a propulsion unit of the designed aircraft which is a combination of a multi-copter and a gyrocopter. This construction was tested for various load patterns to investigate the stresses and strains its profiles are connected. The load patterns correspond to different operation modes of the propulsion system, and the finite element method (FEM) and the SolidWorks software were used for the numerical calculations. The research was done for elastic operation of the individual components of the support platform. The analysis enabled to verify the state of stresses on the critical spots of the construction and to develop a construction for ground and flight tests to verify the correct operation of the propulsion control system and optimize its operation in different flight states.

On the Tripped Rollovers and Lateral Skid in Three-Wheeled Vehicles and Their Mitigation

Active safety systems for three-wheeled vehicles seem to be in premature development; in particular, delta types, also known as tuk-tuks or sidecars, are sold with minimal protection against accidents. Unfortunately, the risk of wheel lifting and lateral and/or longitudinal vehicle roll is high. For instance, a tripped rollover occurs when a vehicle slides sideways, digging its tires into soft soil or striking an object. Unfortunately, research is mostly aimed at un-tripped rollovers while most of the rollovers are tripped. In this paper, models for lateral skid tripped and un-tripped rollover risks are presented. Later, independent braking and accelerating control actions are used to develop a dynamic stability control (DSC) to assist the driver in mitigating such risks, including holes/bumps road-scenarios. A common Lyapunov function and an LMI problem resolution ensure robust stability while optimization allows tuning the controller. Numerical and HIL tests are presented. Implementation on a three-wheeled vehicle requires an inertial measurement unit, and independent ABS and propulsion control as main components.

Formalization of task of movement in longitudinal-transverse plane of tele-controlled underwater vehicles

В статье рассматривается модель движения телеуправляемого необитаемого подводного аппарата в продольной и поперечной плоскостях. Движение телеуправляемого аппарата в маршевом режиме или режимах компенсации перемещений рабочих инструментов достигается комбинацией упоров движителей. Новизна полученных результатов состоит в получении наборов компенсирующих коэффициентов в трёхмерной задаче интерполяции на регулярной сетке. Решение задачи – это частное решение системы дифференциальных уравнений, описывающих динамику телеуправляемого необитаемого аппарата с учётом изменения угла атаки, скольжения и скоростного крена в условиях наиболее распространённого типа движения телеуправляемого необитаемого аппарата. Перекосы в системе управления движителями вызваны неточностями установки в плане прямоугольной платформы с уравновешивающими блоками плавучести движителей, погрешностями изготовления элементов движительно-рулевого комплекса. Динамика движения рассматривается как статистическая задача с усреднением и линеаризацией характеристик упоров движителей, размещённых в плане платформы нулевой плавучести в продольной плоскости. Компенсация перекосов упоров в движительно-рулевом комплексе достигается вычислением коэффициентов компенсации в системе управления по статистикам, полученным в испытательном бассейне методом наименьших квадратов. Скомпенсированная система управления соответствует линейной модели управления телеуправляемого необитаемого аппарата. The article illustrates model of motion of a tele-controlled uninhabited underwater vehicle in longitudinal and transverse planes is considered. Motion of ROV in marching mode or modes of compensation of movements of working tools is achieved by combination of thrusts of propellers. The novelty of the results obtained consists in obtaining sets of compensating coefficients in the three-dimensional interpolation problem on a regular grid. The solution of the problem is a partial solution of a system of differential equations describing the dynamics of a tele-controlled uninhabited apparatus, taking into account changes in the angle of attack, sliding and speed roll in the conditions of the most common type of movement of a tele-controlled uninhabited apparatus. Distortions in the propulsion control system are caused by inaccuracies in the installation in plan of a rectangular platform with balancing units of buoyancy of propulsors, errors in the manufacture of elements of the propulsion-steering system. Motion dynamics is considered as a statistical problem with averaging and linearization of the characteristics of the thrusters of the movers located in terms of the zero buoyancy platforms in the longitudinal plane. Compensation of thrust distortions in the propulsion-steering system is achieved by calculation of compensation coefficients in the control system according to statistics obtained in the test basin using the least squares method. The compensated control system corresponds to a linear control model of a tele-controlled uninhabited apparatus.