This paper presents a novel method for optimizing the contact force of a hexapod robot to enhance its dynamic motion stability when one of its legs *** proposed approach aims to improve the Force Angle Stability Margi...
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This paper presents a novel method for optimizing the contact force of a hexapod robot to enhance its dynamic motion stability when one of its legs *** proposed approach aims to improve the Force Angle Stability Margin(FASM)and adapt the foot trajectory through contact force optimization to achieve safe and stable motion on various *** foot force optimization approach is designed to optimize the FASM,a factor rarely considered in existing contact force optimization *** formulating the problem of enhancing the motion stability of the hexapod robot as a Quadratic Programming(QP)optimization problem,this approach can effectively address this *** of a hexapod robot using a fault-tolerant gait,along with real field experiments,were conducted to validate the effectiveness and feasibility of the contact force optimization *** results demonstrate that this approach can be used to design a motion controller for a hexapod robot with a significantly improved motion *** summary,the proposed contact force optimization method offers a promising solution for enhancing the motion stability of hexapod robots with single leg failures and has the potential to significantly advance the development of fault-tolerant hexapod robots for various applications.
Inverter-based distributed generations(IBDGs)are the main approach to utilizing clean energy in distribution networks(DNs).Compared with synchronous source,fault response of IBDG is very *** a result,in DNs with high ...
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Inverter-based distributed generations(IBDGs)are the main approach to utilizing clean energy in distribution networks(DNs).Compared with synchronous source,fault response of IBDG is very *** a result,in DNs with high penetration of IBDGs,legacy protection schemes will no longer be *** this paper,an energy-based directional pilot protection scheme suitabie for DNs with IBDGs is *** scheme considers the large range of phase angle caused by IBDG integration and uses improved energy polarity criterion to determine fault *** addition,magnitude of energy is used to distinguish between faults and load switching to overcome maloperation of directional pilot protection caused by internal unmeasured load *** proposed scheme first uses local measured information to determine fault direction sign and then exchanges the direction sign with the remote *** scheme does not require high-bandwidth communication and strict data synchronization,so it can be implemented at a low ***,simulation studies verify effectiveness of the proposed scheme.
Design and manufacturing play pivotal roles in hydraulic-driven robotic ***,previous studies have emphasized mainly results and performance,often overlooking the specifics of the design and manufacturing *** paper int...
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Design and manufacturing play pivotal roles in hydraulic-driven robotic ***,previous studies have emphasized mainly results and performance,often overlooking the specifics of the design and manufacturing *** paper introduces a novel approach known as light weight design and integrated manufacturing(LD&IM)for hydraulic wheel-legged *** LD&IM method leverages topology optimization and generative design techniques to achieve a substantial 45%weight reduction,enhancing the robot’s dynamic motion *** innovative design method not only streamlines the design process but also upholds the crucial attributes of light weight construction and high strength essential for hydraulic wheel-legged ***,the integrated manufacturing method,incorporating selective laser melting(SLM)and high-precision subtractive manufacturing(SM)processes,expedites the fabrication of high-quality *** the LD&IM approach,a hydraulic-driven single wheel-legged robot,denoted as WLR-IV,has been successfully *** robot boasts low mass and inertia,high strength,and a simplified component *** assess its dynamic jumping capabilities,the control loop integrates a linear quadratic regulator(LQR)and zero dynamic-based controller,while trajectory planning uses the spring-loaded inverted pendulum(SLIP)*** jumping results confirm the WLR-IV single-legged robot’s exceptional dynamic performance,validating both the effectiveness of the LD&IM method and the rationale behind the control strategy.
With rapid electrification of transportation systems in recent years, the electric vehicle routing problem (EVRP) has received increasing attention. In order to serve a set of valuable transportation tasks using a fle...
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To understand the anisotropy dependence of the damage evolution and material removal during the machining process of MgF_(2) single crystals,nanoscratch tests of MgF_(2) single crystals with different crystal planes a...
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To understand the anisotropy dependence of the damage evolution and material removal during the machining process of MgF_(2) single crystals,nanoscratch tests of MgF_(2) single crystals with different crystal planes and directions were systematically performed,and surface morphologies of the scratched grooves under different conditions were *** experimental results indicated that anisotropy considerably affected the damage evolution in the machining process of MgF_(2) single crystals.A stress field model induced by the scratch was developed by considering the anisotropy,which indicated that during the loading process,median cracks induced by the tensile stress initiated and propagated at the front of the *** cracks induced by tensile stress initiated and propagated on the subsurface during the unloading *** addition,surface radial cracks induced by the tensile stress were easily generated during the unloading *** stress change led to the deflection of the propagation direction of lateral ***,the lateral cracks propagated to the workpiece surface,resulting in brittle removal in the form of chunk *** plastic deformation parameter indicated that the more the slip systems were activated,the more easily the plastic deformation *** cleavage fracture parameter indicated that the cracks propagated along the activated cleavage planes,and the brittle chunk removal was owing to the subsurface cleavage cracks propagating to the crystal *** the same processing parameters,the scratch of the(001)crystal plane along the[100]crystal-orientation was found to be the most conducive to achieving plastic machining of MgF_(2) single *** theoretical results agreed well with the experimental results,which will not only enhance the understanding of the anisotropy dependence of the damage evolution and removal process during the machining of MgF_(2) crystals,but also provide a theoretical foundation for achiev
This paper evaluates three controlsystems for the propulsion of remote-controlled unmanned underwater vehicles utilizing direct current (DC) motors with propellers. Simulation models based on dynamic and static prope...
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Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging *** study presents a novel cable-driven legged landing gear(CLG)with different...
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Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging *** study presents a novel cable-driven legged landing gear(CLG)with differential transmission for unmanned helicopters in complex landing *** obtain the preferred configuration of the legged mechanism,a multi-objective optimization framework for the CLG is constructed by concurrently considering terrain adaptability,landing stability and reasonable linkage of internal *** non-dominated sorting genetic algorithmⅡis employed to numerically acquire the optimal scale parameters that guide the mechanical design of the *** unmanned helicopter prototype equipped with the devised CLG is developed with key performance *** results show that the devised CLG can provide energy-efficient support over uneven terrains(totally driven torque demand less than 0.1 N m)in quasi-static landing tests,and favorable terrain adaptability(posture fluctuation of the fuselage less than±1°)in unknown slope landing *** exhibited merits give the proposed CLG the potential to enhance the landing performance of future aircraft in extreme environments.
Driven by practical applications, the achievement of distributed observers for nonlinear systems has emerged as a crucial advancement in recent years. However, existing theoretical advancements face certain limitation...
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Driven by practical applications, the achievement of distributed observers for nonlinear systems has emerged as a crucial advancement in recent years. However, existing theoretical advancements face certain limitations: They either fail to address more complex nonlinear phenomena, rely on hard-to-verify assumptions, or encounter difficulties in solving system ***, this paper aims to address these challenges by investigating distributed observers for nonlinear systems through the full-measured canonical form(FMCF), which is inspired by full-measured system(FMS) theory. To begin with, this study addresses the fact that the FMCF can only be obtained through the observable canonical form(OCF) in existing FMS *** paper demonstrates that a class of nonlinear systems can directly obtain FMCF through state space equations, independent of OCF. Also, a general method for solving FMCF in such systems is provided. Furthermore, based on the FMCF, A distributed observer is developed for nonlinear systems under two scenarios: Lipschitz conditions and open-loop bounded *** paper establishes their asymptotic omniscience and demonstrates that the designed distributed observer in this study has fewer design parameters and is more convenient to construct than existing approaches. Finally, the effectiveness of the proposed methods is validated through simulation results on Van der Pol oscillators and microgrid systems.
Dear editor,The inherent hysteresis of a piezoelectric actuator(PEA) results in intricate nonlinearity between the output displacement and input voltage, which restricts positioning accuracy of the actuator [1, 2]. Hy...
Dear editor,The inherent hysteresis of a piezoelectric actuator(PEA) results in intricate nonlinearity between the output displacement and input voltage, which restricts positioning accuracy of the actuator [1, 2]. Hysteresis behavior appears as a coupling of nonlinearity, frequency-dependence and memory characteristic, which makes it difficult to comprehensively characterize hysteresis [3]. To eliminate the effect of hysteresis on the positioning accuracy of PEAs,
The development of projection-based stereolithography additive manufacturing techniques and magnetic photosensitive resins has provided a powerful approach to fabricate miniaturized magnetic functional devices with co...
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The development of projection-based stereolithography additive manufacturing techniques and magnetic photosensitive resins has provided a powerful approach to fabricate miniaturized magnetic functional devices with complex three-dimensional spatial ***,the present magnetic photosensitive resins face great challenges in the trade-off between high ferromagnetism and excellent printing *** address these challenges,we develop a novel NdFeB-Fe_(3)O_(4) magnetic photosensitive resin comprising 20 wt.%solid loading of magnetic particles,which can be used to fabricate high-precision and ferromagnetic functional devices via micro-continuous liquid interface production *** resin combining ferromagnetic NdFeB microparticles and strongly absorbing Fe_(3)O_(4) nanoparticles is able to provide ferromagnetic capabilities and excellent printing quality simultaneously compared to both existing soft and hard magnetic photosensitive *** established penetration depth model reveals the effect of particle size,solid loading,and absorbance on the curing characteristics of magnetic photosensitive resin.A high-precision forming and ferromagnetic capability of the NdFeB-Fe_(3)O_(4) magnetic photosensitive resin are comprehensively *** is found that the photosensitive resin(NdFeB:Fe_(3)O_(4)=1:1)can print samples with sub-40μm fine features,reduced by 87%compared to existing hard magnetic photosensitive resin,and exhibits significantly enhanced coercivity and remanence in comparison with existing soft magnetic photosensitive resins,showing by an increase of 24 times and 6 times,*** reported NdFeB-Fe_(3)O_(4) magnetic photosensitive resin is anticipated to provide a new functional material for the design and manufacture of next-generation micro-robotics,electromagnetic sensor,and magneto-thermal devices.
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