Power braking is usually required when mine hoist is at reducing stage, but sPeed closed-loop control is difficultly realized.
交流矿井提升机的减速阶段，一般要求主要用动力制动，但速度闭环控制难实现。
2
In this paper, the hoist and lower automatic control system for stage and orchestra is designed, which is necessary to high technical equipment for those newly built theaters.