Application of auto-landing control in self-propelled carriage to log
2008
Ito, T.(Forestry and Forest Products Research Inst., Tsukuba, Ibaraki (Japan)) | Uemura, T.
To enable the auto-landing of log, we have improved the auto-landing mechanism that is an integral part of automatic operation of self-propelled carriages. Measurements were taken of differential pressures that occurred in the hydraulic motor of the hoisting winch drive while log of 10 m and 4 m in length were being landed. The results clearly showed that there was a temporary but considerable decrease in differential pressure soon after touchdown when the log was lifted up at a certain point away from the center of gravity. This occurred due to slackening of the hoisting cable because the cable momentarily fell faster than the log that was being lodged. On several occasions, the simulation misinterpreted the temporary pressure decrease to mean that landing was completed, so we revised the control program to prevent such misinterpretation. We also created a control program to arrange log in the direction of the skyline by alternately dropping the hoisting cable falling and moving the carriage. When the auto-landing operation was tested using log, automatic operation was accurate and log was arranged in the direction of the skyline according to the plan. Auto-landing operation for the log had been achieved. As a result, it became possible to have automatic operation from transportation to turning back through landing by integrating the auto-landing technique with the auto-traveling technique which had previously been developed.
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