Abstract:Aiming at the unmanned driving problem of underground unmanned vehicles in the roadway environment, an improved PID cascade algorithm is designed based on the improved fuzzy PID algorithm. The improved fuzzy PID algorithm is used as obstacle avoidance algorithm in the steering angle controller and lateral deviation controller.These two controller output steering angle，then the steering angle input the incremental digital PID algorithm.And the proportional electromagnetic valve get the result to control the steering of the vehicle. Experimental results show that the improved PID cascade algorithm has great advantages over the multivariable PID algorithm in terms of response speed and steady-state error.