Despite the progress made in the last decades in the field of machine condition monitoring, there are still cases where the current state of the art is not enough and new technologies and advanced analysis methods are required to prevent unexpected failures. One example is planetary gearboxes (PGs), which are one of the main components of mechanical transmission systems in heavy-duty machines such as off-highway trucks, electric rope shovels, helicopters and wind turbines. Although those machines are usually equipped with vibration and temperature sensors to detect faults in mechanical components, these technologies might not be able to perform well under certain circumstances. Therefore, the applied investigation on new monitoring technologies in the field of machine condition monitoring is a necessary step. Among those, in this review the acoustic emission technology will be addressed as a tool for fault diagnosis of gear faults in PG.

尽管在过去的几十年中在机器状态监控领域取得了进步，但在某些情况下，当前的技术水平还不够，需要新的技术和先进的分析方法来防止意外故障。行星齿轮箱（PG）是一个例子，它是重型机械（如非公路用卡车，电动绳铲，直升机和风力涡轮机）中机械传动系统的主要组件之一。尽管这些机器通常配备有振动和温度传感器以检测机械组件中的故障，但是这些技术在某些情况下可能无法很好地发挥作用。因此，在机器状态监测领域对新型监测技术进行应用研究是必不可少的步骤。在这些，