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从成本收益角度分析菇农自行制棒仍是主要生产方式的原因
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作者 朱新宇 颜廷武 陈思钰 《食药用菌》 2023年第6期378-384,共7页
工厂化专业制棒是未来食用菌产业发展的必然趋势,但自行制棒仍是当前中国菇农主要的生产方式。基于12省599份食用菌种植户调查数据,分种植品种、种植规模比较分析菇农自行制棒与购买专业菌棒进行生产的成本与收益,探究菇农自行制棒仍是... 工厂化专业制棒是未来食用菌产业发展的必然趋势,但自行制棒仍是当前中国菇农主要的生产方式。基于12省599份食用菌种植户调查数据,分种植品种、种植规模比较分析菇农自行制棒与购买专业菌棒进行生产的成本与收益,探究菇农自行制棒仍是当前主要生产方式的内在原因。结果表明:第一,从种植品种来看,菇农通过购买专业菌棒生产香菇、平菇、黑木耳均能获得比自行制棒更高的净收益,其中平菇的净收益在三者中最高;第二,从种植规模来看,小规模香菇种植户和大规模黑木耳种植户采用自行制棒生产方式所获净收益比购买专业菌棒更高,其余菇农通过购买专业菌棒进行生产则更有利;第三,因生产习惯偏好和降低菌棒采购成本而更倾向于自行制棒,忽视了采用专业优质菌棒可能实现更高的净收益,菇农总体表现出不完全理性的特征,这为自行制棒生产方式占据主流提供了一个可能的解释。因此,建议在保障菌棒高质优价前提下加强对工厂化专业菌棒的宣传推广,充分发挥典型种植户的示范引领作用,并通过农业合作社等组织集体统一购买专业菌棒以降低采购成本,引导菇农进行生产方式转型。 展开更多
关键词 自行制棒 购买专业菌 成本收益分析 种植品种 种植规模
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A new robust fuzzy method for unmanned flying vehicle control 被引量:5
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作者 Mojtaba Mirzaei Mohammad Eghtesad Mohammad Mahdi Alishahi 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2166-2182,共17页
A new general robust fuzzy approach was presented to control the position and the attitude of unmanned flying vehicles(UFVs). Control of these vehicles was challenging due to their nonlinear underactuated behaviors. T... A new general robust fuzzy approach was presented to control the position and the attitude of unmanned flying vehicles(UFVs). Control of these vehicles was challenging due to their nonlinear underactuated behaviors. The proposed control system combined great advantages of generalized indirect adaptive sliding mode control(IASMC) and fuzzy control for the UFVs. An on-line adaptive tuning algorithm based on Lyapunov function and Barbalat lemma was designed, thus the stability of the system can be guaranteed. The chattering phenomenon in the sliding mode control was reduced and the steady error was also alleviated. The numerical results, for an underactuated quadcopter and a high speed underwater vehicle as case studies, indicate that the presented adaptive design of fuzzy sliding mode controller performs robustly in the presence of sensor noise and external disturbances. In addition, online unknown parameter estimation of the UFVs, such as ground effect and planing force especially in the cases with the Gaussian sensor noise with zero mean and standard deviation of 0.5 m and 0.1 rad and external disturbances with amplitude of 0.1 m/s2 and frequency of 0.2 Hz, is one of the advantages of this method. These estimated parameters are then used in the controller to improve the trajectory tracking performance. 展开更多
关键词 adaptive fuzzy sliding-mode control unmanned flying vehicle control underactuated system Lyapunov stability high speed underwater vehicle
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H_∞ Robust Fault-Tolerant Controller Design for an Autonomous Underwater Vehicle’s Navigation Control System 被引量:4
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作者 程相勤 曲镜圆 +1 位作者 严浙平 边信黔 《Journal of Marine Science and Application》 2010年第1期87-92,共6页
In order to improve the security and reliability for autonomous underwater vehicle (AUV) navigation, an H∞ robust fault-tolerant controller was designed after analyzing variations in state-feedback gain Operating c... In order to improve the security and reliability for autonomous underwater vehicle (AUV) navigation, an H∞ robust fault-tolerant controller was designed after analyzing variations in state-feedback gain Operating conditions and the design method were then analyzed so that the control problem could be expressed as a mathematical optimization problem. This permitted the use of linear matrix inequalities (LMI) to solve for the Hv controller for the system. When considering different actuator failures, these conditions were then also mathematically expressed, allowing the H∞ robust controller to solve for these events and thus be fault-tolerant. Finally, simulation results showed that the H∞ robust fault-tolerant controller could provide precise AUV navigation control with strong robustness. 展开更多
关键词 AUV navigation control robust H∞ fault-tolerant control gain variations LMI
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