Disclosed is a low-precision incremental
encoder-based method for ultra-
low speed control of a
servo system. According to the present invention, a
fast speed observer in an ultra-low-speed working state is achieved, only a sampling speed and
load torque in an M / T method need to be observed, and position information of an
electric motor does not need to be observed, such that the structure of the observer is simplified, and calculation is simple and fast; moreover, the influence of a
friction force and
cogging torque on a speed change is considered, such that the speed observation precision is further improved. The
fast speed observer can reduce
hysteresis and measurement dead zones, such that the speed response and the speed control precision in a low-speed working state are greatly improved, the problem in a traditional observer of a large position deviation caused by nonlinear factors such as an external load is avoided, improving the stability and robustness of the
system. According to the present invention, the
processing of sampling measurement time at a medium-high speed and the
processing of switching the observer at a
low speed in the M / T method can optimize the
speed measurement precision at both the medium-high speed and the ultra-
low speed, and can better satisfy the requirements of apparatuses such as a
radar on rotating speed control.