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Bagging is a crucial step in the full cycle management of pear cultivation, with increasing labor costs annually, driving research on intelligent bagging equipment. We describe an intelligent bagging end-effector for pears, which employs the Yolov8 algorithm for fruitlets detection and the Semi-Global Block Matching (SGBM) algorithm to acquire three-dimensional spatial information of the targets. To address the computational limitations of embedded devices in agricultural intelligent equipment, we improve the YOLOv8 model by replacing its neck component with the Asymptotic Feature Pyramid Network (AFPN) and incorporating Context Guided (CG) blocks into the C2f module. These improvements significantly reduce the model’s parameters and size while enhancing detection accuracy. To provide accurate three-dimensional information to the end-effector, we use the SGBM algorithm to obtain depth information of the targets. We constrain the matching process based on the model’s detected candidate bounding boxes and binocular prior knowledge, which improves the matching accuracy of the model while reducing the computational load. Finally, we deploy the model and matching algorithm on a Jetson Nano, which serves as the controller for the bagging end-effector based on the vacuum negative pressure principle. Experimental results show that the improved model achieves a precision of 96%, an increase of 1.4% over YOLOv8, with the size reduced from 6.2M to 5.0M. The depth information accuracy obtained by the algorithm is within 3cm. The improved model, combined with SGBM, runs at 11.5 fps on the Jetson Nano embedded device, meeting real-time performance requirements.

Design and development of a high power, widebandwidth W-band travelling wave tube (TWT) is presented in this paper. The design and simulation covers folded waveguide (FWG) circuit, electron gun, periodical permanent magnet system, and coupling window with the emphasis on the FWG optimization and particle-in-cell simulation by Computer Simulation Technology (CST) particle studio. Two TWT prototypes have been developed and tested, which demonstrate over 30-W output power in frequency between 91 and 101 GHz with over 30-dB saturated gain. Maximum power was found to be about 40 W around 95 GHz, while the flat output power curve under same drive level was observed. [ABSTRACT FROM PUBLISHER]

W-band TWTs are key devices for high-frequency and high-power amplifiers used in high-resolution imaging applications. This paper presents the design, simulation, and fabrication of W-band pulsed TWTs. For higher power and broader bandwidth, TWTs have been developed using all-metal folded waveguide (FWG) slow-wave structures, diamond-disc windows, and horseshoe-shaped carbonized alumina attenuators. The test results show that W-band FWG pulsed TWTs can reach over 100 W output power with 6.7 GHz bandwidth and over 33 dB saturated gain at 20% duty cycle, while the maximum output power exceeds 200 W. [ABSTRACT FROM AUTHOR]

W-band Folded Waveguide (FWG) TWTs with moderately high-power and broad-bandwidth are a key device for many applications, such as radar and imaging systems. This letter presents the development of a 10 GHz bandwidth 100 W W-band FWG pulsed TWT. The test results show that this TWT is capable to offer over 100 W output power with 10.1 GHz bandwidth. [ABSTRACT FROM PUBLISHER]