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Mobile robots are being widely used in smart manufacturing, and efficient task assignment and path planning for these robots is an area of high interest. In previous studies, task assignment and path planning are usually solved as separate problems, which can result in optimal solutions in their respective fields, but not necessarily optimal as an integrated problem. Meanwhile, precedence constraints exist between sequential processing operations and material delivery tasks in the manufacturing environment. Thus, those planning methods developed for warehousing and logistics may not simply apply to the environment of smart factories. In this paper, we propose an integrated task and path planning approach based on Looking-backward Search Strategy (LSS) and Regret-based Search Strategy (RSS). In the stage of task assignment, the real paths for mobile robots are identified based on the Cooperative A* (CA*) algorithm and the time and energy consumed by mobile robots and machining centers are calculated. Then a greedy strategy working with LSS or RSS is used to search reasonable task assignments in time-series, which can generate a joint optimal solution for both task assignment and path planning. We verify the validity of the proposed approach in a simulated smart factory and the results show that our approach can improve the operation efficiency of the smart factory and save the time and energy consumption effectively.

The nanocatalysts of VOx deposited on ZrO2 supports with single monoclinic (ZrO2‐M), tetragonal (ZrO2‐T), and binary monoclinic‐tetragonal (ZrO2‐MT) phase were synthesized. VOx/ZrO2‐MT catalysts exhibit better performance during propane nonoxidative dehydrogenation than VOx/ZrO2‐M and VOx/ZrO2‐T catalysts. Among VOx/ZrO2‐MT catalysts, the conversion and deactivation rate constant of VOx/ZrO2‐M31T69 catalyst is 35.2% and 0.22 h−1, respectively. The promoting role of ZrO2‐MT is revealed by experiments and theoretical calculations. The MT‐mixed phase structure in VOx/ZrO2‐MT catalyst improves the structural properties and dispersion of VOx. The tetragonal‐monoclinic transformation on the ZrO2‐MT surface facilitates VOx reduction and produces additional V3+ active sites. The highly dispersed V3+ sites on the ZrO2‐MT surface accelerate CH bond breaking and boost the desorption of propylene, which is the key reason for enhancing activity and stability during the reaction, respectively. Insight into the role of surface phase transformation of ZrO2‐MT is expected to obtain high‐efficient catalysts further.

Propane direct dehydrogenation (PDH) has received much attention. How to effectively catalyze inert C–H bond activation is of great significance for industrial development. Pt-based catalysts show excellent activity but are limited by their expensive price. Cr-based catalysts are scarcely applied owing to their high toxicity. V-based catalysts are appropriate candidates for their cheap price and low toxicity, but they suffer from high energy consumption. The photothermal synergy effect induced by nonradiative relaxation is expected to make the C–H bond activation and hydrogen coupling process easier compared to bare thermal catalysis. Herein, a set of V/TiO2 nanoscale catalysts were synthesized. The optimized 3 wt % V/TiO2 catalyst (hereafter simplified as 3V) has a particle size of ∼26 nm, achieving a propylene production rate of 342 μmol·g–1·h–1 at 500 °C with UV–vis light radiation, which is 9.2% higher compared with bare thermal conditions. In situ radiation X-ray photoelectron spectroscopy (XPS) shows that photon injection leads to more electron-deficient V atoms (Vδ+, 5 > δ > 3). The strengthened Lewis acidity enhances the C3H8 activation as revealed by kinetic evidence and in situ C3H8-DRIFT measurements. The calculated molecular orbital diagrams show that the V atoms decrease the energy gap between the highest occupied orbital (HOMO) of C3H8 and the lowest unoccupied orbital (LUMO) of the model catalyst. This work describes an efficient photothermal synergy approach, specifically the nonthermal effect for promoting propane dehydrogenation.