A newcontrolled seed metering unit was designed and mounted on a common grain drill for direct seeding of wheat(DSW).It comprised the following main parts:(a)a variable-rate controlled direct current motor(DCM)as seed...A newcontrolled seed metering unit was designed and mounted on a common grain drill for direct seeding of wheat(DSW).It comprised the following main parts:(a)a variable-rate controlled direct current motor(DCM)as seed metering shaft driver,(b)two digital encoders for sensing the rotational speed of supplemental ground wheel(SGW)and seed metering shaft and(c)a control box to handle and process the data of the unit.According to the considered closed-loop control system,the designed control box regularly checked the revolution per minute(RPM)of seed metering shaft,as operation feedback,using its digital encoder output.The seeding ratewas determined based on the calculated error signal and output signal of the digital encoder of the SGW.A field with four different levels of wheat stubble coverage(10%,30%,40%and 50%)was selected for evaluation of the fabricated seed metering unit(FSMU).The dynamic tests were conducted to compare the performance of installed FSMU on the grain drill and equipped grain drill with common seed metering unit(CSMU)at three forward speeds of 4,6 and 8(Km/h)for DSW.Results of the FSMU assessment demonstrated that an increase in forwardspeed of grain drill(FSGD)and stubble coverage did not significantly affect the seeding rate in the grain drill forDSW.Using theFSMU reduced the coefficient of variation(CV)by approximately 50%.Consequently,applying the FSMU on the common grain drill led to a desirable seeding rate at different forward speeds of the grain drill and stubble existence.展开更多
针对复杂装备体系(Complex Equipment System-of-systems,CES)优化设计中指标变量多、仿真依赖性强、易陷入局部最优的问题,提出一种基于正向解析式和多目标博弈理论(Multi-Objective Game Theory,MOGT)优化算法的CES优化设计方法。为提...针对复杂装备体系(Complex Equipment System-of-systems,CES)优化设计中指标变量多、仿真依赖性强、易陷入局部最优的问题,提出一种基于正向解析式和多目标博弈理论(Multi-Objective Game Theory,MOGT)优化算法的CES优化设计方法。为提升CES优化设计的可解释性,构建任务级—能力级—装备级的评估指标体系;在此基础上,基于装备机理和效用函数表征装备评估指标与作战能力之间的正向映射关系,并利用相邻优属度熵权法计算各指标权重;通过正向解析式与约束条件建立多目标优化模型,并采用MOGT优化算法获得最佳优化结果。以某作战推演平台中防空攻防想定为例,开展算例评估与验证分析。研究结果表明,该方法能够实现CES中最优设计方案的求解,可显著提高设计效率和降低设计成本,为下一代装备发展论证、设计评估和作战试验提供了基础性工作。展开更多
文摘A newcontrolled seed metering unit was designed and mounted on a common grain drill for direct seeding of wheat(DSW).It comprised the following main parts:(a)a variable-rate controlled direct current motor(DCM)as seed metering shaft driver,(b)two digital encoders for sensing the rotational speed of supplemental ground wheel(SGW)and seed metering shaft and(c)a control box to handle and process the data of the unit.According to the considered closed-loop control system,the designed control box regularly checked the revolution per minute(RPM)of seed metering shaft,as operation feedback,using its digital encoder output.The seeding ratewas determined based on the calculated error signal and output signal of the digital encoder of the SGW.A field with four different levels of wheat stubble coverage(10%,30%,40%and 50%)was selected for evaluation of the fabricated seed metering unit(FSMU).The dynamic tests were conducted to compare the performance of installed FSMU on the grain drill and equipped grain drill with common seed metering unit(CSMU)at three forward speeds of 4,6 and 8(Km/h)for DSW.Results of the FSMU assessment demonstrated that an increase in forwardspeed of grain drill(FSGD)and stubble coverage did not significantly affect the seeding rate in the grain drill forDSW.Using theFSMU reduced the coefficient of variation(CV)by approximately 50%.Consequently,applying the FSMU on the common grain drill led to a desirable seeding rate at different forward speeds of the grain drill and stubble existence.
文摘针对复杂装备体系(Complex Equipment System-of-systems,CES)优化设计中指标变量多、仿真依赖性强、易陷入局部最优的问题,提出一种基于正向解析式和多目标博弈理论(Multi-Objective Game Theory,MOGT)优化算法的CES优化设计方法。为提升CES优化设计的可解释性,构建任务级—能力级—装备级的评估指标体系;在此基础上,基于装备机理和效用函数表征装备评估指标与作战能力之间的正向映射关系,并利用相邻优属度熵权法计算各指标权重;通过正向解析式与约束条件建立多目标优化模型,并采用MOGT优化算法获得最佳优化结果。以某作战推演平台中防空攻防想定为例,开展算例评估与验证分析。研究结果表明,该方法能够实现CES中最优设计方案的求解,可显著提高设计效率和降低设计成本,为下一代装备发展论证、设计评估和作战试验提供了基础性工作。
