Analysis of Stability of Forestry Vehicles Driven on Inclined Forest Land

本研究的目的是分析在倾斜林地上行驶的林业车辆的稳定性，并给出临界俯仰角和横摇角。研究结果总结如下：1)从形态结构和操作功能两方面对林业车辆进行分类；即滑板车型，运输车（轮式）：小型货代型，运输车（履带式）：农用拖拉机型和移动堆场型。2)通过对小型货代车辆静稳定性试验结果的分析，论证了支腿在小型货代车辆装载作业中的重要性。3)通过对装载和空载小型货代车辆在林地、滑行道和林道上行驶的俯仰角和侧倾角的测量，明确了在林地上行驶的车辆出现最大的振荡角，即俯仰角为14-21度，侧倾角为12-17度。4)由静稳定角和振荡稳定角计算临界稳定角。特别是在对林业车辆有重要意义的横向上，得到了路面19 ~ 24度和林地9 ~ 12度作为横摇角的暂定判据。5)在倾斜林地上，车辆的运动分析仍需采用动力学方法，其中包括悬架系统试验和质量转动惯量分析。

The purposes of this study are to analyze the stability of forestry vehicles driven on inclined forest land, and to show critical pitch and roll angle of stability.The results obtained from the study are summarized as follows ;1) Forestry vehicles can be classified from the view point of morphological structure and operational functions of vehicles ; namely Skidder type, Transporter (Wheeled) : Mini-forwarder type, Transporter (Crawler) : Farm tractor type and Mobile yarder type.2) Importance of outrigger was approved in loading operation with Mini-forwarder type vehicles by analysis of results obtained from static stability test of them.3) From the measurements of pitch and roll angle of the loaded and nonloaded Mini-forwarder type vehicle driven on forest land, skid road and forest road, it was clarified that maximum oscillatory angles appear in the vehicles driven on forest land : namely pitch angle is 14-21 degree and roll angleis 12-17 degree.4) The critical angle of stability is calculated from static stability angle and oscillatory angle. Especially, in lateral direction that is meaningful to forestry vehicles, the values of 19-24 degree in skid road and 9-12 degree in forest land are obtained as the tentative criteria of oscillatory angle of roll.5) It was remained in future that the motion of vehicles driven on inclined forest land is analyzed by means of dynamics in which tests of suspension system and analysis of mass moment of inertia are contained.