This paper proposes a modified iterative learning control(MILC)periodical feedback-feedforward algorithm to reduce the vibration of a rotor caused by coupled unbalance and parallel *** control of the vibration of the ...
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This paper proposes a modified iterative learning control(MILC)periodical feedback-feedforward algorithm to reduce the vibration of a rotor caused by coupled unbalance and parallel *** control of the vibration of the rotor is provided by an active magnetic actuator(AMA).The iterative gain of the MILC algorithm here presented has a self-adjustment based on the magnitude of the *** filters are adopted to extract the synchronous(1×Ω)and twice rotational frequency(2×Ω)components of the rotor *** the notch frequency of the filter and the size of feedforward storage used during the experiment have a real-time adaptation to the rotational *** method proposed in this work can provide effective suppression of the vibration of the rotor in case of sudden changes or fluctuations of the rotor *** and experiments using the MILC algorithm proposed here are carried out and give evidence to the feasibility and robustness of the technique proposed.
Salient object detection(SOD)in RGB and depth images has attracted increasing research *** RGB-D SOD models usually adopt fusion strategies to learn a shared representation from RGB and depth modalities,while few meth...
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Salient object detection(SOD)in RGB and depth images has attracted increasing research *** RGB-D SOD models usually adopt fusion strategies to learn a shared representation from RGB and depth modalities,while few methods explicitly consider how to preserve modality-specific *** this study,we propose a novel framework,the specificity-preserving network(SPNet),which improves SOD performance by exploring both the shared information and modality-specific ***,we use two modality-specific networks and a shared learning network to generate individual and shared saliency prediction *** effectively fuse cross-modal features in the shared learning network,we propose a cross-enhanced integration module(CIM)and propagate the fused feature to the next layer to integrate cross-level ***,to capture rich complementary multi-modal information to boost SOD performance,we use a multi-modal feature aggregation(MFA)module to integrate the modalityspecific features from each individual decoder into the shared *** using skip connections between encoder and decoder layers,hierarchical features can be fully *** experiments demonstrate that our SPNet outperforms cutting-edge approaches on six popular RGB-D SOD and three camouflaged object detection *** project is publicly available at https://***/taozh2017/SPNet.
This paper discusses the H∞ consensus problem of leader-follower multi-agent systems. The controller for each agent is crafted to utilize comprehensive information from all connected agents, while an innovative event...
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A large-scale highway infrastructure monitoring system requires a complex and heterogeneous data transmission network to transmit different types and large amounts of sensor data. In order to meet the requirement of r...
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In the field of railway transportation, with the continuous improvement of train running speed and the continuous increase of operating mileage, it becomes particularly important to ensure the safety and integrity of ...
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Birds improve their aerodynamic performance and flight maneuverability through wing folding and deformation. Inspired by this, we designed a flapping wing with rigid-flexible coupling folding and angle of attack (AOA)...
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ISBN:
(数字)9798350385724
ISBN:
(纸本)9798350385731
Birds improve their aerodynamic performance and flight maneuverability through wing folding and deformation. Inspired by this, we designed a flapping wing with rigid-flexible coupling folding and angle of attack (AOA) adjustment in this paper. Our flapping wing can mimic birds’ wing leading edge bending during the upstroke and leading edge expanding during the downstroke. It can also actively adjust the AOA during the flapping to enhance the aerodynamic performance and maneuverability. Firstly, we designed the rigid-flexible coupling wing mechanism, including the leading-edge passive bending mechanism and the AOA active adjustment mechanism. Subsequently, we performed aerodynamic modeling of the wing flapping and verified the feasibility of the design using numerical simulation. Lastly, we designed a flapping wing robot prototype and conducted wing performance experiments. Results show that our leading-edge passive bending mechanism can enhance the aerodynamic performance of the wing, and the AOA active adjustment mechanism can increase the wing’s lift.
Elastic rods are commonly seen in our daily life. Although humans are sensitive to the shape change of rods, it is not intuitive to estimate the external forces applied to generate the deformation. We propose a method...
Elastic rods are commonly seen in our daily life. Although humans are sensitive to the shape change of rods, it is not intuitive to estimate the external forces applied to generate the deformation. We propose a method to interactively track the elastic linear objects by using the Cosserat rod model to regulate the captured noisy points. We develop a framework based on particle filters to work with the physics-based model, turning the inverse physics problem into a forward simulation and search problem. We show that with the proposed method, we can simultaneously digitalize the shape as well as the external forces on real-world elastic rods. With these capabilities, we demonstrate virtual and augmented reality applications to facilitate the interaction with elastic linear objects. The tracking performance is also validated with experiments.
Birds and insects achieve remarkable aerial maneuvering skills through the primary and passive deformation of their wings. We proposed a wing design method based on origami for a flapping-wing robot (FWR) mimicking la...
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ISBN:
(数字)9798350385724
ISBN:
(纸本)9798350385731
Birds and insects achieve remarkable aerial maneuvering skills through the primary and passive deformation of their wings. We proposed a wing design method based on origami for a flapping-wing robot (FWR) mimicking ladybugs. First, we designed a wing deformation mechanism, which includes an active folding mechanism and an passive unfolding mechanism. Second, we performed rigid-flexible coupled multibody dynamics simulations to verify the feasibility of the wing design scheme and provide design parameters for the robot prototype fabrication. Third, we designed the robot prototype, with dimensions of $32.5 \mathrm{~cm} \times 43.91 \mathrm{~cm} \times 14.6 \mathrm{~cm}$ and a weight of 429.35 g. Finally, experimental testing was conducted on the robot, showing that the folding time of the wings is 3.7 s, the unfolding time is 3.8 s, and the folding ratio is $\mathbf{6 2. 3 8 1 \%}$. Additionally, we tested and compared the required tension of the robot wings with theoretical analysis for validation. The folding wings designed in this paper possess the merits of simple structure, lightweight, fast folding speed, and high efficiency. Furthermore, wing folding can significantly reduce aerodynamic drag, enabling the FWR to improve aerodynamic performance and reduce energy consumption during both upstroke and downstroke.
Soft landing on weightless asteroids is challenging in space exploration missions. This paper proposes a cable-driven landing gear system (LGS) with rigid-flexible coupled structures (RFCSs) for the soft landing of a ...
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ISBN:
(数字)9798350355369
ISBN:
(纸本)9798350355376
Soft landing on weightless asteroids is challenging in space exploration missions. This paper proposes a cable-driven landing gear system (LGS) with rigid-flexible coupled structures (RFCSs) for the soft landing of a spacecraft on asteroids. The cable-driven mechanism improves the compliance of the spacecraft’s landing legs and has the merits of being lightweight and compact. The RFCS minimizes the impact force of the landing legs when crashing the asteroid’s surface. We designed a three-legged LGS and formulated its kinematics and dynamics. We conducted simulations and experiments of a simplified spacecraft prototype. The results showed that the spacecraft can safely land on rough slopes, with the legs contacting the ground at different sequences. The collision speeds of $10-50 \mathrm{~cm} / \mathrm{s}$ are verified. This study provides a new idea for the landing and operation of these cable-driven RFCS probes in a weightless environment. The results are valuable for the design of asteroid landers and their stabilizing control.
Autonomous takeoff of flapping-wing robots (FWRs) is crucial for accelerating response speed and reducing costs in executing tasks. Jumping-aided takeoff is an effective method adopted by birds. However, the limited p...
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ISBN:
(数字)9798350377705
ISBN:
(纸本)9798350377712
Autonomous takeoff of flapping-wing robots (FWRs) is crucial for accelerating response speed and reducing costs in executing tasks. Jumping-aided takeoff is an effective method adopted by birds. However, the limited power density of motors poses challenges in achieving this type of takeoff for FWRs. In this study, we introduce a ground-based FWR ejecting system that utilizes a symmetric slider-crank mechanism (S-SCM) to store energy in spring. This stored energy is then converted into the takeoff speed of the FWR. The dynamic model of each working stage is established, and the design parameters are optimized according to simulation results. The prototype of the FWR ejecting system is fabricated for experimental validations. The results indicate that the system can provide a takeoff speed of 4 m/s for the 270 g FWR. Notably, the system is deployable on rough terrains and only adds a 3.2 g payload to the robot. Our work advances the autonomous takeoff of FWRs, promoting the application of such robots.
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