Abstract This paper focuses on robust optimal adaptive control strategy to deal with tracking problem of a quadrotor unmanned aerial vehicle (UAV) in presence of parametric uncertainties, actuator amplitude constraints, and unknown time-varying external disturbances. First, Lyapunov-based indirect adaptive controller optimized by particle swarm optimization (PSO) is developed for multi-input multi-output (MIMO) nonlinear quadrotor to prevent input constraints violation, and then disturbance observer-based control (DOBC) technique is aggregated with the control system to attenuate the effects of disturbance generated by an exogenous system. The performance of synthesis control method is evaluated by a new performance index function in time-domain, and the stability analysis is carried out using Lyapunov theory. Finally, illustrative numerical simulations are conducted to demonstrate the effectiveness of the presented approach in altitude and attitude tracking under several conditions, including large time-varying uncertainty, exogenous disturbance, and control input constraints.

Osmotic dehydration is a method to partially remove moisture from vegetables and fruits. Three sucrose concentrations (20, 30 and 40% w/w) in four temperatures (30, 40, 50 and 60ºC) were used in this study. Effective diffusion coefficient was determined for examined temperatures and concentrations using Fick's second law of diffusion adapted to slab geometry. The calculated effective diffusion coefficients of water were of the order of 10-9 m²/s. Activation energy was calculated and found to be 17.533, 4.861 and 5.446kJ/mol for 20, 30 and 40% w/w solutions, respectively.