The invention realizes stepless variation of auto transmission ratio, and resolves the problem of weak transmission force of the present variable speed case at the same time.

In case of the noise statistic being unknown or variable, adaptive Kalman filter is used to get drift speed of each axle at each test position, and then drift parameter is calculated.

Introduces the working-case and the controlling-process of the mine lift, analyses the principle of variable frequency adjust speed and energy saving in terms of theory.