The cup-chain metering device is commonly used in potato planters despite its problems of missing-seeding,double-seeding and ground wheel sliding.A mechanical-electrical design was developed for planters to resolve these problems.A regression experiment was conducted with three factors(chain speed,chain tightening distance and cup tilting)and two indicators(missing-seeding rate and double-seeding rate).Based on the results of regression experiment,a numerical regression model was built and a multi-objective optimization method was used to get an optimal solution.Subsequently,the optimized device was tested in the field.The device design presents a tilting seed cup with a guard plate and an electric control system.The laboratory test showed that the missing-seeding rate increased with the chain speed.It initially decreases and then increases with the chain tightening distance and cup tilting angle.The double-seeding rate declines with chain speed.It increases initially and declines afterward with the chain tightening distance.The optimization resulted in a missing-seeding rate of 4.39%and a double-seeding rate of 8.78%under the parameters of 0.32 m/s seeding speed,0.94×10-3 m tightening distance,and 12.5°cup tilting angle.The field test demonstrated that electric control instead of ground wheel-driven chain enables fast seeding and precise intra-row seeding distance.
