Quadcopter unmanned aerial vehicle is a multivariable, coupled, unstable, and underactuated system with inherent nonlinearity. It is gaining popularity in various applications and has been the subject of numerous research studies. However, modelling and controlling a quadcopter to follow a trajectory is a challenging issue for which there is no unique solution. This study proposes an optimal hybrid quadcopter control with MPC-based backstepping control for following a reference trajectory. The outer-loop controller (backstepping controller) regulates the quadcopter’s position, whereas the inner-loop controller (Model Predictive Control) regulates its attitude. The translational and rotational dynamics of the quadcopter are analyzed utilizing the Newton-Euler method. After that, the backstepping controller (BC) is created, which is a recurrent control method according to Lyapunov’s theory that utilizes a genetic algorithm (GA) to choose the controller parameters automatically. In order to apply a linear control technique in the presence of nonlinearities in the quadcopter dynamics, Linear Parameter Varying (LPV) Model Predictive Control (MPC) structure is developed. Simulation validated the dynamic performance of the proposed optimal hybrid MPC-based backstepping controller of the quadcopter in following a given reference trajectory. The simulations demonstrate the fact that using a command control input in trajectory tracking, the proposed control algorithm offers suitable tracking over the assigned position references with maximum appropriate tracking errors of 0.1 m for the �� and �� positions and 0.15 m for the �� position.

In this work, a new dual-evaporator CO2transcritical refrigeration cycle with two ejectors is proposed. In this new system, we proposed to recover the lost energy of condensation coming off the gas cooler and operate the refrigeration cycle ejector free and enhance the system performance and obtain dual-temperature refrigeration simultaneously. The effects of some key parameters on the thermodynamic performance of the modified cycle are theoretically investigated based on energetic and exergetic analysis. The simulation results for the modified cycle indicate more effective system performance improvement than the single ejector in the CO2vapor compression cycle using ejector as an expander ranging up to 46%. The exergetic analysis for this system is made. The performance characteristics of the proposed cycle show its promise in dual-evaporator refrigeration system.

Celem tekstu jest dyskusja z teoriami mówiącymi o tym, że dzisiejsze społeczeństwa nie są zdolne do integracji opartej na powszechnie podzielanych normach. Teza o „zaniku wspólnych sensów” daje obraz społeczeństwa jako agregatu jednostek lub skonfliktowanych grup. Jako kontrprzykład do takich konkluzji autor proponuje pojęcie norm średniego zasięgu. Zgodnie z prezentowanym ujęciem, takie normy mogą łączyć zróżnicowanych aktorów społecznych i być powszechnie uznawane. Wspólna normalność może być negocjowana oddolnie i niekoniecznie jest odgórnie narzucana przez różne formy władzy społecznej. Przykłady takich norm autor znajduje w rzeczywistości życia codziennego. Zalicza do nich normę niemarnowania żywności, regułę gościnności, szacunku dla żałoby, opiekuńczość wobec dzieci oraz dbanie o własne zdrowie.