whirlabout meaning in English

n.
旋转，盘旋。

Whirlabout flat drive system adopts direct current electromotor and servo system is closed loop . the system carries out the response of adjusting shipboard 90 ? within 1 . 8 seconds and orientates accurate position simultaneously ( the error is within ? ? )
同时为实现1 . 8秒调舷90的响应，并调舷定位在精确方位上(误差在20之内) ，伺服系统以线性? ?非线性系统来实现。