As a core component of a fully automatic pepper transplanter, the performance of the seedling-picking mechanism is of particular significance. However, existing seedling-picking mechanisms have problems such as being prone to damaging the seedling roots and substrate, as well as having poor stability. To develop a highly efficient, stable, and minimally damaging seedling-picking mechanism, this study proposed a design scheme for a stem-clamping-and-pulling-out-type seedling-picking end actuator driven by a non-circular gear system. The specific methods and objectives include the following: (1) designing a differential non-circular gear system to replicate a manual picking trajectory accurately; (2) establishing a kinematic model and developing optimization software to determine the optimal parameter combination; (3) experimentally validating the mechanism’s performance through virtual simulations and bench tests. The bench tests showed that the mechanism could complete two seedling-picking operations per rotation, extracting an entire row (eight plants) in a single rotation at a speed of 30 r/min. The measured angles of the end effector at four key postures were highly consistent with simulation and high-speed camera data, with all key posture errors less than 1°. These results demonstrate the mechanism’s high accuracy, efficiency, and reliability.

The knot-forming motions of knotters are difficult to directly observe, and knotting tests are labor-intensive and time-consuming. To address these issues, a novel test bench motion scheme was proposed to simulate the bundling process of a bale, and a performance test bench for a single-knot knotter was developed under controllable indoor conditions. The bench can verify the working principles of different knotters and assess the knotting success rate. To meet the requirements of unattended and safe operations for long-term continuous knotting tests, an automatic control process for the test bench was constructed to identify the knot-releasing failure and twine breakage fault based on monitoring the pressure of the simulated bale. By establishing the corresponding relationships between knotting actions and image states, a test and analysis method for detecting the motion timing sequences of the knotter was developed. This allowed us to obtain a motion timing diagram of the knotter, which can provide references for its reverse design or performance evaluation. The results of the continuous knotting tests show that the tested knotter achieved a knotting success rate of 99.57%, and the test bench can meet the performance testing requirements of the knotter.

As a carbon-free alternative fuel for internal combustion engines (ICEs), ammonia (NH ₃ ) is gaining popularity in global decarbonization and sustainable transportation initiatives. Ammonia reduces CO ₂ emissions due to its hydrogen-rich composition and minimal carbon content. Its use in combustion engines presents unique and complex emission challenges that differ from those of hydrocarbon fuels. Unburned ammonia (NH ₃ slip), nitrogen oxides (NO _x ), and nitrous oxide (N ₂ O) pose significant environmental, health, and regulatory risks. This comprehensive evaluation examines emissions from ammonia-fueled engines. It reviews recent literature on combustion behavior, pollutant formation processes, and advanced aftertreatment technologies. Dual-fuel strategies, such as ammonia-hydrogen and ammonia-diesel, and their impacts on flame propagation, emissions control, and fuel reactivity are discussed. The paper also considers the performance and selectivity of SCR systems, AMOX catalysts, and AI-driven adaptive control frameworks. Tables, statistics, and performance graphs illustrate emission trends, thermal management requirements, and trade-offs across different operating conditions. The durability, regeneration, and poisoning resistance of catalytic materials in real-world applications are thoroughly examined. Researchers, engineers, and policymakers can utilize this mini-review to identify potential obstacles in developing clean, efficient, and scalable ammonia-powered vehicle systems.