Variable stiffness mechanisms(VSMs)are a class of compliant mechanisms that can adjust their intrinsic stiffness,which promises to be beneficial in applications needed to interact with the environment,such as collabor...
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Variable stiffness mechanisms(VSMs)are a class of compliant mechanisms that can adjust their intrinsic stiffness,which promises to be beneficial in applications needed to interact with the environment,such as collaborative robots,wearable robots,and polishing *** paper presents the design and optimization of a novel linear VSM,called cLVSM,to produce linear motion,conversely to the majority of VSMs designed to perform rotary *** changing the effective length of specially designed circular beams,the cLVSM is capable of continuous stiffness regulation from a minimum value to almost *** from the VSMs which need rotation-to-translation converting mechanisms for stiffness regulation,the stiffness of the proposed design is adjusted by directly rotating the beams without the use of additional mechanisms,which contributes to improving the structural compactness,and reducing the energy loss and error in ***,the beam rotation needed to regulate the stiffness is almost perpendicular to the beam deflection force,which helps to reduce the torque needed for stiffness *** stiffness model of the proposed VSM is developed using the screw theory,and the design parameters are optimized using the genetic *** effectiveness of the mathematical model and the performance of the design are verified by simulation and experiments.
Oracle bone inscriptions are the earliest mature writing system in China. Research on the character recognition of oracle bone inscriptions is of great significance for interpreting ancient history and culture. Howeve...
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A 2 m class robotic drill was sent to the Moon and successfully collected and returned regolith samples in late 2020 by *** was a typical thick wall spiral drill(TWSD)with a hollow auger containing a complex coring sy...
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A 2 m class robotic drill was sent to the Moon and successfully collected and returned regolith samples in late 2020 by *** was a typical thick wall spiral drill(TWSD)with a hollow auger containing a complex coring system to retain subsurface regolith *** the robotic drill was launched,a series of laboratory tests were carried out to investigate and predict the possible drilling loads it may encounter in the lunar *** work presents how the sampling performance of the TWSD is affected by the regolith *** and analysis during the drilling and sampling process in a simulated lunar regolith environment were *** compressibility of a typical lunar regolith simulant(LRS)was measured through unidirectional compression tests to study the relationship between its inner regolith stress and bulk density.A theoretical model was established to elucidate the cutting discharge behavior by auger flights based on the aforementioned *** were conducted with the LRS,and the results show that the sampling performance is greatly affected by the flux of the drilled cuttings into the spiral flight *** work helped in scheduling reasonable drilling parameters to promote the sampling performance of the robotic drill in the Chinese Chang’E 5 mission.
In this paper, the trajectory tracking problem of the Unmanned Aerial Vehicle (UAV) is considered. Firstly, different from the accurate models adopted in most of existed works, we consider a concise and effective mode...
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This paper introduces a novel prediction method for a quadcopter model based on Koopman operator theory. Due to the inherently high non-linearity of the quadcopter dynamics, the proposed method leverages the Koopman o...
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Controllable canonical forms play important roles in the analysis and design of control *** this paper,a fundamental class of discrete-time bilinear systems are *** systems are of interest since,on one hand,they have ...
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Controllable canonical forms play important roles in the analysis and design of control *** this paper,a fundamental class of discrete-time bilinear systems are *** systems are of interest since,on one hand,they have the most complete controllability *** the other hand,they can be nearly-controllable even if controllability ***,controllability of the systems with positive control inputs is studied and necessary and sufficient algebraic criteria for positive-controllability and positive-near-controllability are ***,controllable canonical forms and nearly-controllable canonical forms of the systems are presented,respectively,where the corresponding transformation matrices are also explicitly *** are given to demonstrate the effectiveness of the derived controllability criteria and controllable canonical forms.
This paper presents a software turbo decoder on graphics processing units(GPU).Unlike previous works,the proposed decoding architecture for turbo codes mainly focuses on the Consultative Committee for Space Data Syste...
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This paper presents a software turbo decoder on graphics processing units(GPU).Unlike previous works,the proposed decoding architecture for turbo codes mainly focuses on the Consultative Committee for Space Data Systems(CCSDS)***,the information frame lengths of the CCSDS turbo codes are not suitable for flexible sub-frame parallelism *** mitigate this issue,we propose a padding method that inserts several bits before the information frame *** obtain low-latency performance and high resource utilization,two-level intra-frame parallelisms and an efficient data structure are *** presented Max-Log-Map decoder can be adopted to decode the Long Term Evolution(LTE)turbo codes with only small *** proposed CCSDS turbo decoder at 10 iterations on NVIDIA RTX3070 achieves about 150 Mbps and 50Mbps throughputs for the code rates 1/6 and 1/2,respectively.
At present, modern large-scale astronomical observation equipment can collect a large number of high-resolution images. Astronomy has entered the era of big data. Deep learning has shown great potential in astronomica...
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Fisheye cameras offer a significantly larger field of view compared to conventional cameras,making them valuable tools in the field of computer ***,their unique optical characteristics often lead to image distortions,...
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Fisheye cameras offer a significantly larger field of view compared to conventional cameras,making them valuable tools in the field of computer ***,their unique optical characteristics often lead to image distortions,which pose challenges for object detection *** address this issue,we propose Yolo-CaSKA(Yolo with Contrastive Learning and Selective Kernel Attention),a novel training method that enhances object detection on fisheye camera *** standard image and the corresponding distorted fisheye image pairs are used as positive samples,and the rest of the image pairs are used as negative samples,which are guided by contrastive learning to help the distorted images find the feature vectors of the corresponding normal images,to improve the detection ***,we incorporate the Selective Kernel(SK)attention module to focus on regions prone to false detections,such as image edges and blind ***,the mAP_(50) on the augmented KITTI dataset is improved by 5.5% over the original Yolov8,while the mAP_(50) on the WoodScape dataset is improved by 2.6% compared to *** results demonstrate the performance of our proposed model for object detection on fisheye images.
This paper proposes a novel voltage stability assessment method to calculate the static voltage stability margin and identify the vulnerable buses with consideration of N-1 contingencies for power systems. Firstly, th...
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