In this paper,the fixed-time stability of spacecraft formation reconfiguration(position tracking)is ***,a novel nonsingular terminal sliding mode surface is designed and based on which a fixed-time coordinated control...
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In this paper,the fixed-time stability of spacecraft formation reconfiguration(position tracking)is ***,a novel nonsingular terminal sliding mode surface is designed and based on which a fixed-time coordinated controller is designed to keep the closed-loop system states have a finite settling time bounded by some predefined ***,another nonsingular terminal sliding mode surface is designed by combining the artificial potential function and the aforementioned sliding surface,which meets the mutual distance constraint during transition process among spacecraft when it is *** another coordinated controller with fixed-time observer considering mutual distance constraint is presented,which guarantees the closed-loop system states stable also in bounded settling ***,simulation results are shown to validate the correctness of the proposed *** is worth mentioning that the control schemes also work even though there is a properly limit on the control input.
In this paper a parametric family of stabilizing controllers for a nonlinear discrete control system is obtained for different values of a parameter at the system matrix. An algorithm for constructing a stabilizing co...
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In multimodal multiobjective optimization problems(MMOPs),there are several Pareto optimal solutions corre-sponding to the identical objective *** paper proposes a new differential evolution algorithm to solve MMOPs w...
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In multimodal multiobjective optimization problems(MMOPs),there are several Pareto optimal solutions corre-sponding to the identical objective *** paper proposes a new differential evolution algorithm to solve MMOPs with higher-dimensional decision *** to the increase in the dimensions of decision variables in real-world MMOPs,it is diffi-cult for current multimodal multiobjective optimization evolu-tionary algorithms(MMOEAs)to find multiple Pareto optimal *** proposed algorithm adopts a dual-population framework and an improved environmental selection *** utilizes a convergence archive to help the first population improve the quality of *** improved environmental selection method enables the other population to search the remaining decision space and reserve more Pareto optimal solutions through the information of the first *** combination of these two strategies helps to effectively balance and enhance conver-gence and diversity *** addition,to study the per-formance of the proposed algorithm,a novel set of multimodal multiobjective optimization test functions with extensible decision variables is *** proposed MMOEA is certified to be effective through comparison with six state-of-the-art MMOEAs on the test functions.
The author considers the problem of optimal tracking with a given reference trajectory and singular disturbances for the case of proportional-integral-differential control laws. The application of the decoupling metho...
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The photocatalytic CO_(2) cycloaddition to prepare high value-added chemicals,such as cyclic carbonates(CCs)under mild conditions is an effective strategy to realize carbon ***,through a three-step reaction,the porphy...
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The photocatalytic CO_(2) cycloaddition to prepare high value-added chemicals,such as cyclic carbonates(CCs)under mild conditions is an effective strategy to realize carbon ***,through a three-step reaction,the porphyrin-based covalent organic polymer with bimetallic active sites(Fe-COP-Zr)is successfully obtained by coordinating Fe^(2+) and Zr^(4+)with porphyrin and bipyridine(Bpy),*** to excellent photosensitivity of porphyrin moieties,Fe-COP-Zr exhibits outstanding visible light absorption,which is very important for the production of photogenerated ***,Fe-COP-Zr shows high photocatalytic performance towards CO_(2) cycloaddition with a yield of 12.1 mmol/h,which is 6 times higher than that of pure covalent organic polymer(COP)and 3 times higher than that of monometallic *** reason for this excellent photocatalytic CO_(2) cycloaddition performance may be ascribed to the synergistic effect of Fe and Zr *** photogenerated electrons are easily injected into epichlorohydrin(ECH)through Fe—O bonds to form affluent electron transition state,and interact with Zr^(4+) as Lewis acid sites for the ring-opening of ECH,which is the rate-determining step for the visible light boosted chemical fixation of CO_(2) into *** work might provide some insights for design and preparation of COPs with multiple active sites to modulate their photocatalytic activities.
This paper explores a multi-agent containment problem, where a fast evader, modeled having constant speed and using constant heading, attempts to escape a circular containment region that is orbited by a slower team o...
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The increasing of satellite launch missions, collisions and disintegration events of space objects, and the vast number of near-Earth asteroids pose significant challenges to space traffic management. Space situationa...
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In this study,we fabricated multifunctional metastructures from carbon fiber-reinforced plastic composites using additive manufacturing *** metastructures are characterized by their lightweight,load-bearing capacity,a...
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In this study,we fabricated multifunctional metastructures from carbon fiber-reinforced plastic composites using additive manufacturing *** metastructures are characterized by their lightweight,load-bearing capacity,and broadband low-frequency sound absorption *** metastructure consists of 36 unit cells,and non-local coupling mechanism was considered for designing the sound absorption *** developed an acoustic impedance theory tailored for the metastructure,facilitating an analysis of thermal and viscous dissipation *** is proven theoretically and experimentally that the proposed composite metastructure can achieve a noise reduction with an average sound absorption coefficient greater than 0.9 across frequencies in the rage of 330-1500 *** also studied the metastructure’s quasi-static and cyclic compression performance,confirming its efficient absorption capabilities after cyclic *** proposed design and additive manufacturing method for composite metastructures provides a novel pathway for creating lightweight,multifunctional structures with diverse applications,such as aerospace engineering.
This paper deals with the problem of combining task and motion planning for a manipulator system. We propose a linear temporal logic (LTL) approach which follows the traditional hierarchical planning process, includin...
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The impulse sound source generated by the "hydro-electric effect"has great development potential in the fields of rock breaking, geosteering, location determination, hydro-electric forming, water treatment a...
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