This paper proposes a finite time convergence sliding mode control (FSMC) strategy based on linear parameter-varying (LPV) methodology for the stability control of a morphing aircraft subject to parameter uncertainties and external disturbances. Based on the Kane method, a longitudinal dynamic model of the morphing aircraft is built. Furthermore, the linearized LPV model of the aircraft in the wing transition process is obtained, whose scheduling parameters are wing sweep angle and wingspan. The FSMC scheme is developed into LPV systems by applying the previous results for linear time-invariant (LTI) systems. The sufficient condition in form of linear matrix inequality (LMI) constraints is derived for the existence of a reduced-order sliding mode, in which the dynamics can be ensured to keep robust stability and L2 gain performance. The tensor-product (TP) model transformation approach can be directly applied to solve infinite LMIs belonging to the polynomial parameter-dependent LPV system. Then, by the parameter-dependent Lyapunov function stability analysis, the synthesized FSMC is proved to drive the LPV system trajectories toward the predefined switching surface with a finite time arrival. Comparative simulation results in the nonlinear model demonstrate the robustness and effectiveness of this approach.

Porous asphalt concrete (PAC) has an open-graded aggregate mixture to yield high air voids; PAC is mainly applied to the surface drainage layer on high-speed trafficked highway pavements. The objective of the study was to investigate the effect of binder types on the engineering properties and field performance of PAC mixtures. Three binder types were selected for a 19-mm nominal maximum aggregate size gradation: conventional asphalt AR-80, polymer-modified asphalt, and high-viscosity asphalt. A series of laboratory tests were conducted to evaluate the engineering properties of the PAC mixture, including permeability, resistance to draindown, resistance to disintegration, resistance to rutting, and resistance to indirect traction. A 3-km in-service test road was constructed to monitor the performance of PAC pavements using these three binders. Polymer-modified binder was shown to minimize abrasion loss and enhance the durability of the PAC mixture. Test results indicated that the use of polymer-modified binder, instead of unmodified binder, reduced rutting and raveling. When the mixture contained high-viscosity binder, it showed the best performance in the field. Field measurements indicated improved drainage as a result of replacement of the conventional asphalt AR-80 binder with the polymer-modified and high-viscosity binders. PAC pavement surfaces provided good frictional characteristics once the asphalt binder film was worn from the aggregate.

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Cold recycling technology is a widely applied asphalt pavement rehabilitation technology. e properties of emulsified asphalt residues after water evaporates play an important role in the performance of the asphalt pavement. is paper investigates the rheological and fatigue properties of emulsified asphalt residues under different evaporation methods. Two different matrix asphalt binders and emulsifiers were selected to prepare the emulsified asphalt. Moreover, the direct heating method (DHM) and the EN13074 and ASTM D7497-09 evaporation methods were used to obtain emulsified asphalt residues. Furthermore, the linear viscoelasticity, the permanent deformation resistance, and the fatigue resistance were evaluated by the temperature sweep and frequency sweep tests, the multiple stress creep recovery (MSCR) test, and the linear amplitude sweep (LAS) test, respectively. e test results show that under the three evaporation conditions, the growth amplitude order of the rutting factor, recovery percent, complex modulus, and fatigue life of emulsified asphalt residues is ASTM D7497-09 > EN13074 > DHM, and as is the attenuation amplitude order of the nonrecoverable creep compliance and phase angle. e results reveal that the evaporation process leads to oxidation and hardening of the residues. e hardening degree of the ASTM D7497-09 evaporation method is higher than that of the EN13074 evaporation method, and the hardening degree of the EN13074 evaporation method is higher than that of the direct heating method. e rheological and fatigue performances of the emulsified asphalt residues depend on the matrix asphalt. Moreover, the residue that was prepared from 70# asphalt has good high-temperature and fatigue properties, but it has higher temperature sensitivity and stress sensitivity.

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