Abstract: Speed control difficulty caused by nonlinear and strong interference is the bottleneck problem through the operation efficiency of the tractor hoist.Taking a caterpillar tractor hoist as a research object,an expert fuzzy PID control system of the tripping in operation speed based on tractor hoist was put forward,and the expert control rules were established.then the control device of tripping in operation speed for the tractor hoist was developed,and the workover test of the workover well in the tractor hoist was carried out.The results proved that the expert-fuzzy PID control system can achieve good control of the workover and reduce the working intensity of the workers and improve the efficiency and safety of the workover operation compared with the traditional manual control.

Key words: tractor hoist, expert control, fuzzy PID control