An Improved Fuzzy Logic Control Method for Combine Harvester's Cleaning System.

Impurities rate and losses rate are two main indicators for the performance of a cleaning system in combine harvester. The impurities rate and losses rate are affected by both the external environment factors and mechanical structural parameters of the system. To obtain an ideal cleaning effect, an effective control strategy, which should be able to adjust the key controlled variables based on the real-time working parameters detection, is required. Due to the nonlinear process of grain harvesting, there is no precise mathematical model to describe the behavior of the cleaning system. By means of combining fuzzy logic control (FLC) theory and expert knowledge, this paper presents an improved FLC algorithm for the cleaning system which is mounted in our self-designed combine harvester. A control system is developed to implement the proposed algorithm. Experiments were conducted to evaluate the cleaning performance. The average values of the impurities rate and losses rate in low, middle and high modes based on our fuzzy control method are 1.66 and 1.69%, which are better than the corresponding values of 2.13 and 2.11% from the classical control method. The results show that the established control system is reliable and effective to improve harvest efficiency. [ABSTRACT FROM AUTHOR]