학습제어를 이용한 지게차 자동변속기 상향 변속품질 개선 = An Upshift Improvement in the Quality of Forklift’s Automatic Transmission by Learning Control

다국어 초록 (Multilingual Abstract)

Recently, automatic transmissions caused a good improvement in the shift quality of a forklift. An advanced shift control algorithm, which was based on TCU firmware, was applied with embedded control technology and microcontrollers. In the clutch-to-clutch shifting, one friction element is released and the other friction element is activated. During this process, if the release and application timings are not synchronized, an overrun or tie-up occurs and ultimately leads to a shift shock. The TCU, which measures only the speed of the forklift, inevitably applies the open-loop shift control. In this situation, the speed ratio does not change during the clutch fill. The torque phase occurs until the clutch is disengaged. In this study, an offline shift logic of the learning control was proposed. It induced a synchronous shift when the learning control progressed. During this process, the reference current trajectory of the release clutch was corrected and applied to the next upshift. We considered the results of the overrun/tie-up characteristics of the upshift performed immediately before. The vehicle test proved that the deviation in shift quality, which was caused by the difference in the mechanical characteristics of the clutch, could be improved by the learning control.

참고문헌 (Reference)

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6 C. H. Song, "Development of the Learning Control Logic Considering Hysteresis for Internal Resistance in Dry-type Engine Clutch in Parallel Hybrid System" 48-48, 2015

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