针对标准型往复式切割器切割棉秆过程中动刀片磨损严重以及易出现棉花秸秆被动刀片前桥向前推倒、劈裂等问题,该文在分析往复式切割器切割图的基础上,提出了切割有效率的概念,并以切割有效率为研究目标,采用仿真技术和响应面法,研究了动刀片的结构参数(动刀片宽度、刀刃高度、前桥宽度)对切割有效率的影响,同时利用高速摄像系统观察分析了动刀片前桥形状对棉秆切割质量的影响；通过响应面分析,优化了动刀片的结构参数,建立了目标值与各影响因素之间的回归模型,并对模型进行了验证；通过高速摄像技术优化了动刀片前桥的形状,提高了棉秆切割质量。试验结果表明,动刀片宽度、刀刃高度、前桥宽度以及两两之间的交互作用对切割有效率都具有显著影响,动刀片前桥形状对棉秆切割质量有重要影响。优化设计的动刀片的结构参数是:动刀片宽度为90 mm、刀刃高度为52 mm、前桥宽度为15 mm、前桥形状为圆弧型,此时的切割有效率为96.148 2%。利用优化设计的动刀片,在棉花秸秆切割试验台上进行了棉秆切割试验,试验结果表明,新型动刀片的棉花秸秆割茬高度的平均值比标准型动刀片割茬高度的平均值低5.9 mm,棉花秸秆单位面积切割功的平均值降低了6.1%,棉花秸秆割茬截面平整率提高了12%。研究结果可为高效、低耗的棉花秸秆往复式切割器的设计提供参考。

China is one of the most important cotton?producing areas in the world.It is well known that cotton stalk is a kind of renewable biomass energy resource and can be widely used.Therefore, it is very important to research the harvesting techniques and equipment of cotton stalk, and design the cutting blade of cotton stalk.The conception of cutting effective rate was put forward on the basis of analyzing the cutting pattern of the reciprocating cutter, and it was used to describe the cutting characteristics of reciprocating cutter, because the cutting pattern of the reciprocating cutter could describe the cutting quality and height of the stubble of cotton stalk.In order to explore the effect of the knife section structural parameters(the width, height, and leading end width of the knife section) as well as the operating parameters(the average cutting velocity was 0.9 m/s, and the ratio of cutting velocity to feeding velocity was 1.25) on cutting effective rate of cotton stalk reciprocating cutter, and optimize the structural parameters of the knife section, the simulation test was performed with the ADAMS software.The simulation testing scheme designed with the box?behnken design(BBD) method was a three?factor three?level testing scheme, and the testing factors were the width of the knife section, the height of the knife section cutting edge, and the width of the leading end.The response surface analysis method was used to analyze the simulation testing data and optimize the knife section structural parameters of the cotton stalk reciprocating cutter.In order to observe and analyze the cutting process and morphological structure of the stubble as well as optimize the profile of the knife section, the cutting test was performed with a cutting test bench of cotton stalk by the high?speed photography technology.The samples were the ripe cotton stalks with the diameter of 11.7-13.2 mm, and the moisture content of 31%-37%, which were collected from a cotton field located at Shanghe County, Shandong Province.The results obtained from the response surface test showed that the effects of the width of the knife section, the height of the knife section cutting edge, and the width of the leading end on the objective value(the cutting effective rate) were significantly different(P<0.01), and the effects of the interactions between the width of the knife section and the height of the knife section cutting edge, between the width of the knife section and the width of the leading end, and between the height of the knife section cutting edge and the width of the leading end on the objective value were also significantly different(P<0.01).By analyzing the sequence images of cutting process of cotton stalk from the cutting test by the high?speed photography technology for cotton stalk, it was known that the effects of the different profile of the leading ends on the cutting quality of cotton stalk and the height of the stubble of cotton stalk were significantly different.It was concluded that the optimal combination of the knife section structural parameters of cotton stalk reciprocating cutter was that the width of knife section was 90 mm, the height of knife section cutting edge was 52 mm, the width of leading end was 15 mm, and the profile of leading end was arc?shaped.On the basis of the results of the verifying tests, it was found that the cutting effect of cotton stalk for cotton stalk reciprocating cutter with the new knife section was good, the height of cotton stalk cutting stubbles of the optimized knife section was 5.9 mm shorter than the standard knife section′s, the average value of cutting power per unit area of cotton stalk for the optimized knife section was 6.1% less than the standard knife section′s, and the smoothness of cutting stubble section of cotton stalk for the optimized knife section was 12% more than the standard knife section′s.The results of this research can provide technical support not only for developing a new cotton stalk cutter, but also for designing the equipment for harvesting hard stalk with a large planting area.

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国家“863”计划资助项目(2009AA043601)；教育部博士点基金项目(20133702110011)；山东农业大学青年科技创新基金项目。