为解决凿岩台车臂定位系统与液压臂结构不匹配而出现液压臂下降时抖动、平动速度慢、泵压过高等问题，系统分析液压臂下降时抖动的原因，指出液压臂下降时抖动是由于液压臂下部液压缸平衡阀的先导油源压力不稳引起的，并通过试验证实，如果下降过程中下部液压缸平衡阀的先导油源压力一直大于其开启压力，液压臂能够平缓下降。可以通过提高液压臂油源压力和增大下部液压缸回油背压来解决液压臂下降抖动问题。

In order to solve the problems of jitter, slow translational speed and high pump pressure when the hydraulic arm falls due to the structure mismatch between the jumbo arm positioning system and the hydraulic arm，the reason of jitter of hydraulic arm is analyzed systematically, and it is pointed out that the jitter of the hydraulic arm is caused by the instability of the hydraulic cylinder balance valve under the hydraulic arm.And through the test, if the pilot oil source pressure of the lower hydraulic cylinder balance valve is always greater than the opening pressure, the hydraulic arm can gently decline. The jitter problem of hydraulic arm drop can be solved by increasing the pressure of hydraulic arm oil source and increasing the back pressure of the lower hydraulic cylinder.