Bleeding constitutes an essential stage in pre-processing operations for fish products. In China, this process remains entirely manual, characterized by low efficiency, high labor intensity, and operational hazards, creating a pressing demand for versatile automated equipment in the market. To address the mechanization requirements for efficient freshwater fish bloodletting, we developed an automated fish bleeding machine based on gill-based blood extraction principles, incorporating an impact-triggered positional bleeding methodology. The positional triggering mechanism was engineered through kinematic and dynamic analyses of fish sliding trajectories onto the trigger plate, informed by morphological parameters of fish specimens. This design achieved automated positional awareness and bleeding activation. A reciprocating bleeding mechanism was developed by mimicking manual bleeding motions, leveraging the quick-return motion characteristics of an offset crank-slider mechanism. The transmission system combined chain-drive and clutch mechanisms to enable sequential and intermittent power delivery. Experimental validation employed live specimens of snakehead (Channa argus), grass carp (Ctenopharyngodon idellus), and tilapia (Oreochromis mossambicus), with systematic evaluations including sensory assessments, comparative testing, and performance metrics. Results demonstrated a comprehensive sensory evaluation score of 3.8 for bleeding efficacy; significant influence of baffle geometry on performance, identifying V-shaped baffles as optimal; a bleeding success rate averaging 94% with throughput reaching 1417 fish/hour. The integrated workflow—directional feeding, postural constraint, positional triggering, reciprocating bleeding, and automated ejection—established a cyclic mechanized bleeding process with industrial applicability.

To address the inefficiencies of two-stage sweet potato harvesting in southern China, an integrated machine for synchronous haulm shredding and tuber excavation was developed. The equipment features a front-mounted, reverse-rotating crushing knife roller and a rear-mounted, adjustable grate-type digging shovel. The performance of the prototype was systematically evaluated through two-stage field trials in clay loam soil. First, an orthogonal test was employed to assess the haulm shredding quality. The results indicated that the knife roller speed significantly increased the qualified rate of crushed stems and leaves, whereas the forward speed exerted a negative effect. Additionally, the blade-to-ridge clearance primarily dictated the ridge-top stubble length. Second, a quadratic orthogonal rotational composite design was utilized to optimize the integrated harvesting parameters. The analysis demonstrated that shovel inclination significantly enhanced the tuber exposure rate, while both clearance and inclination exhibited quadratic nonlinear effects on the tuber damage rate. Multi-objective optimization established the optimal operational parameters as a blade-to-ridge clearance of 66.6 mm and a shovel inclination of 34.0°. Field validations under these settings achieved a tuber exposure rate of 83.7% and a damage rate of 4.3%, confirming the high reliability of the predictive models. The integrated equipment effectively shortens the harvesting cycle and demonstrates robust adaptability to clayey moist soils, thereby advancing the mechanization of sweet potato production.