The Model Predictive Control (MPC) trajectory tracking problem of an unmanned quadrotor with input and output constraints is addressed. In this article, the dynamic models of the quadrotor are obtained purely from operational data in the form of probabilistic Gaussian Process (GP) models. This is different from conventional models obtained through Newtonian analysis. A hierarchical control scheme is used to handle the trajectory tracking problem with the translational subsystem in the outer loop and the rotational subsystem in the inner loop. Constrained GP based MPC are formulated separately for both subsystems. The resulting MPC problems are typically nonlinear and non-convex. We derived a GP based local dynamical model that allows these optimization problems to be relaxed to convex ones which can be efficiently solved with a simple active-set algorithm. The performance of the proposed approach is compared with an existing unconstrained Nonlinear Model Predictive Control (NMPC). Simulation results show that the two approaches exibit similar trajectory tracking performance. However, our approach has the advantage of incorporating constraints on the control inputs. In addition, our approach only requires 20% of the computational time for NMPC.

The catalytic cycle and activity of methanol-to-olefin conversion over low-silica AlPO-34 zeolites can be effectively altered by changing the Brønsted acid density.

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Flexible electrochromic supercapacitors (FECSCs) for powering wearable electronics have attracted considerable attention. Silver nanowires (AgNWs) are one kind of the most potential flexible transparent electrodes (FTEs) materials for the emerging flexible devices. Currently, fabricating FECSC based on AgNWs FTEs is still hindered by their intrinsic poor electrochemical stability. To address this issue, a hybrid AgNWs/Co(OH)2/PEDOT:PSS electrode is proposed. The PEDOT:PSS could not only improve the resistance against electrochemical corrosion of AgNWs, but also work as functional layer to realize the electrochromic and energy-storage properties. Moreover, the Co(OH)2 interlayer further improved the electrochromic and energy-storage performance. Based on the improvement, we further assembled the symmetrical FECSCs. Under the same condition, the areal capacitance (0.8 mF/cm2) and coloration efficiency (269.8 cm2/C) of AgNWs/Co(OH)2/PEDOT:PSS FECSC were obviously higher than AgNWs/PEDOT:PSS FECSC. Furthermore, the obtained FECSC exhibited excellent stability against the mechanical deformation. The areal capacitance remained stable during 1000 times cyclic bending with a 25-mm curvature radius. These results demonstrated the broad application potential of the AgNWs/Co(OH)2/PEDOT:PSS FECSC for the emerging portable and multifunctional electronics.

Conductive polymer composites (CPCs) with high conductivity and flexibility play a crucial role in emerging flexible electronics. However, the facile fabrication of high-performance flexible conductors is still challenging due to cumbersome manufacturing steps and the need for expensive metal nanomaterials as conductive fillers. Herein, we presented a facile and cost-effective method to prepare CPCs with an ultralow resistivity of 2.4 × 10–5 Ω·cm at 60% silver micronflakes. The elastic CPCs are simply composed of conductive cofillers of commercial silver micronflakes and polyaniline/halloysite nanotubes (PANI/HNTs) and water-based polyurethane (WPU) resin as the matrix. With a delicate design, the PANI/HNTs could locate adjacent silver micronflakes in the WPU resin and form conducting paths to improve the electrically conductive performance of the composites significantly. Thus, the CPCs serve as flexible conductors showing high conductivity and excellent stability during numerous cyclic mechanical deformations, such as bending, stretching, twisting, and folding. These advantages make the valuable materials candidates for the next generation of flexible conductors.