Design And Study On Simplified Film Stripper For Tabacco Seedling

Plastic film mulching technology can significantly increase the yield and quality of crops,and it has been widely used in agricultural production.However,severe farmland pollution,even “white pollution” in some areas,has been caused by the large amount of residual film and crops have been reduced in production,because it is difficult for plastic film to degrade under natural conditions.This turns to be a prominent problem of the current green development of agriculture.Tobacco is an important economic crop in China.Plastic film mulching is widely used in tobacco cultivation.In the early days with low temperature of transplanting tobacco seedlings in the field,the heat preservation effect of plastic film can significantly promote the growth of tobacco seedlings.However,in the middle and late growth stages of tobacco,especially in low altitude areas,plastic film tends to have a negative effect on tobacco growth as the temperature rises,therefore stripping plastic film for tobacco seedling is proposed.In addition,the film strength of the seedling stage is better,and plastic film is easy to recycle.Then,as the use period of plastic film becomes longer,plastic film is aging severely,which makes it more difficult to recover.Therefore,it is important to design and study on a kind of simplified film stripper for tabacco seedling,which could contribute to solve the film recycling problem in hilly and mountainous regions,and to promote the green development of agriculture as well as increase the degree of agricultural mechanization.This dissertation carried out design and study on the simplified film stripper for tabacco seedling,which employs a film stripping motor to drive a conical roll to uncover the film.During the process of stripping the film,the film stripping motor could drive the conical roll to uncover the film with a constant torque based on the control system.Therefore,the film stripper could strip the film with a near constant force,ensuring reliable and continuous film removal.The film stripper was composed of a film stripping system,a control system and a walking system.The film stripping system implemented film stripping and film offloading,and mainly consisted of the conical roll,the film stripping motor,the drive mechanism,the film locking plate and the film collecting mechanism.The control system realizes the independent control and constant-torque drive of the two-side film stripping motors.The walking system provides support and movement functions.The film pulling and snap force experiments were carried on.The experiment results indicated that the film stripping force range was 25.91 N~41.83 N and the film stripping torque range 1.55 N·m~2.51 N·m was acquired associated with the structural size of the conical roll.The force,stress and displacement of conical film stripping mechanism were analyzed,and the finite element model of the conical roll was established and simulated.The constant torque control principle of the motor was analyzed.Through the constant current output characteristic test of the film stripping motor,the regression equation of the film stripping motor's current and torque,and the equation of current and film stripping force were obtained.Based on the equations,the control of constant current was designed.The hardware circuit design and software design of the control system were completed.The hardware circuit design included the film stripping motor's drive circuit,the setting stripping force circuit,the current detection circuit,the walking speed detection circuit,the battery voltage detection circuit as well as alarm and prompt circuit.The software design program included the main program,the battery voltage detection program,the constant current control program,the interrupt service program,the alarm and prompt subroutine,and the like.The constant torque experiment of the film stripper showed that the average constant current control error of the control system was 2.46%,and the average constant torque control error was 4.12%.Field Experiment of prototype showed that when the film stripping force was 30.9 N,corresponding current of the film stripping motor 2.9 A,the film recovery rate of the film stripper was 93.24%,and the tobacco injury rate was 1.94%,which demonstrated the film stripping performance was good enough to meet the application requirements.