Abstract: In agricultural production, the period from 3 to 5 leaves after maize emergence is critical for weeding operations. Currently, mechanized inter-row weeding technology for maize has become relatively mature. However, due to the limited and discontinuous operation space between plants, intra-row mechanized weeding still faces numerous challenges, hence chemical and manual weeding remain the primary methods. Addressing the issues of low weeding efficiency and high seedling damage rate in existing maize intra-row weeding devices, this study designed a lightweight swing-type sine rotary yoke weeding device for intra-row in maize cultivation to enhance weed management in maize fields. This research introduces a Coordinate Attention (CA) module before the SPPF layer of the YOLOv5s model to enhance the network's focus on maize seedling targets, suppressing the interference of irrelevant information such as weeds on detection results. The detection accuracy was improved by 0.84 percentage points compared to the YOLOv5s model, which was 94.7%, and outperformed YOLOv5s in mAP, F1, and P performance metrics. The device takes a single intra-row area as the minimum operational unit. When the vision system detects an intra-row segment and feeds back to the control system, the control system determines whether the area can complete weeding and seedling protection actions based on the current vehicle speed and intra-row segment information. When the intra-row segment meets the minimum threshold for operation, the control system will actuate the motor to rotate, and the reducer outputs rotational movement to both sides of the sine rotary yoke mechanism, driving the push rods to push the weeding ends on both sides for seedling protection and weeding operations. Furthermore, the trajectory and absolute speed of the weeding blade directly affect the device's seedling protection and weeding effect. Therefore, this study conducted an in-depth analysis of the motion trajectory of the weeding blade and determined its limit speed. Ultimately, a response surface analysis method was used for a three-factor, three-level combination experiment to optimize operational parameters. The factors considered in the study include the device's forward speed, crop protection zone diameter, and the weeding blade's penetration depth into the soil, with the indicators being weeding efficiency, seedling damage rate, and energy consumption. The results showed that the device's forward speed had the most significant impact on weeding efficiency (P<0.01), the crop protection zone diameter had the most significant impact on seedling damage rate (P<0.01), and the weeding blade's penetration depth into the soil had the most significant impact on energy consumption (P<0.01). In the verification experiment conducted under the optimal parameter combination, with a forward speed of 0.42 m/s, a crop protection zone diameter of 74 mm, and a weeding blade penetration depth of 18 mm, the device achieved a weeding efficiency of 92.75%, a seedling damage rate of 2.91%, and power consumption of 129.7 W, meeting the requirements for intra-row weeding during maize field management. Fifteen days after the field trials concluded, observations were made in the weeded areas, and it was found that although some weeds, located at the edge of the crop protection zone, still had roots in the soil and a tendency to continue growing, the majority of the weeds had been eradicated. The device demonstrated excellent seedling protection and weeding effects, as well as a low weed recovery rate, providing important references for practical production applications and machine upgrades.