Adaptive model predictive control of a six-rotor electric vertical take-off and landing urban air mobility aircraft subject to motor failure during hovering

In this article, motor failure control of a six-rotor electric vertical take-off and landing (eVTOL) urban air mobility aircraft is investigated using adaptive model predictive control (MPC) based on the linear parameter-varying (LPV) model developed using the nonlinear rigid-body aircraft model. For capturing the aircraft dynamics under motor failure conditions, a family of linearized models are obtained by trimming the nonlinear aircraft model at multiple equilibrium conditions and the LPV model is obtained by linking the linear models using the failed rotor speed, where the system transition from healthy to failure is modeled by a scheduling parameter calculated based on failed rotor speed caused by available motor peak power after failure. The proposed adaptive MPC is developed to optimize the system output performance, including the rigid-body aircraft velocity and altitude, by using quadratic programming optimization with reference compensation subject to a set of time-varying constraints representing the current available propeller acceleration calculated based on the motor power. Simulation study is conducted based on the developed LPV control design and original nonlinear rigid-body model, and the simulation results demonstrate that the designed adaptive MPC controller is able to recover and maintain the aircraft at desired stable condition after motor failure.

Физически корректные конфигурационные пространства в описании внутренней динамики жесткой молекулы

A family of configuration spaces in the description of the internal dynamics of a rigid molecule has been considered. It has been shown that the requirement of the physical correctness of the description leads to serious restrictions for such spaces. In particular, only spaces satisfying the Eckart condition are allowed for a nonlinear rigid molecule.

Modeling, Identification, and Adaptive Robust Motion Control of Voice-Coil Motor Driven Stages

Voice-coil motors are widely used in precision motion control of industrial applications such as head positioning of hard disk drives, semiconductor fabrication and packaging. In this paper, to achieve high precision movement potential of vertical voice-coil motor driven stages, the accurate modeling of nonlinear rigid body dynamics is developed, and the model parameters are estimated by the identification experiments in time domain. The neglected high-frequency dynamics are also identified through frequency response experiments to verify the validity of the frequency range of the proposed rigid-body dynamical model. To attenuate the serious nonlinear effect of the plant dynamics, Coulomb friction compensation is used when obtaining the frequency response results. Based on the verified nonlinear rigid-body dynamical model, an adaptive robust controller is developed to obtain a guaranteed performance in the presence of both parametric uncertainties and uncertain nonlinearities. Comparative control experimental results obtained show the effectiveness and good tracking performance of the proposed ARC algorithm.

Research on the Shock Response of 3-DOF Tangent and Nonlinear Rigid Body Packing System

The buffering model of nonlinear rigid body packing system is established and the vibration equations are achieved. Through a series of transformation, the state variables of the oscillatory differential equation are obtained. The shock response spectrum curved surfaces of the system, which is shocked by the final peak pulse, are calculated by using the Runge-Kutta method.

A New Method for Modeling of Fully Flexible Aircrafts

The purpose of this study is to produce a modeling capability for integrated flight dynamics of flexible aircraft that can better predict some of the complex behaviors in flight due to multi-physics coupling. Based on the studying of the exiting modeling approaches, the author put forward a new modeling method, and developed a new formulation integrating nonlinear rigid-body flight mechanics and linear aeroelastic dynamics for fully elastic aircrafts using Lagrangian mechanics. The new equations of motion overcome the disadvantages of the exiting methods, and include automatically all six rigid-body degrees of freedom and elastic information, the seamless integration is achieved by using the same reference frame and the same variables to describe the aircraft motions and the forces acting on it, including the aerodynamic forces. The formulation is modular in nature, in the sense that the structural model, the aerodynamic theory, and the controls method can be replaced by any other ones to better suit different types of aircraft.