To realize the auto-pick up of plug seedlings by 2Y–2 type semi-auto transplanter, an auto plug seedling pick-up mechanism constituted with sector gear, grooved cam and retractable seedling clip is designed. As the wheel hub-shaped grooved cam influences the motion trajectory, main structural parameters including the law of motion, center-to-center spacing, the length of swing rod and polar radius were designed and calculated. And orthogonal test was applied on the depth reached, the installing angle, the moisture content of the matrix and the...