Research on Truck Speed Tracking Method Based on Preview and Fuzzy Rule for Open-Pit Mines

The whole operation process of mining trucks used in open-pit coal mines involves transporting coal or rock from the pit bottom to the ground surface for unloading. In this process, fully loaded trucks navigate unstructured roads characterized by varying gradients, including both upslopes and downslopes, and potholes of different sizes. These challenging road conditions often lead to unstable speed control, resulting in frequent coal/rock drops, particularly on slopes. Consequently, following trucks may perceive these drops as obstacles and stop abruptly, further exacerbating the dropping problem and creating a vicious cycle, which greatly reduces the operating efficiency of these trucks. However, the existing feedforward + PI control method falls short in solving this issue. In this regard, this paper proposes a speed tracking method specifically for open-pit mine trucks operating on unstructured roads. First, the upper-level controller calculates the expected acceleration, leveraging a working mode adjustment method based on road preview and a rule table. Then, the lower-level controller employs a dynamic calibration table method to calculate the truck's throttle opening and electric braking percentage, taking actuator delay into account. This approach enables the stable tracking of expected speeds for trucks operating on unstructured roads. Experimental results based on real trucks showed that the implementation of the proposed speed tracking control method based on preview and the rule table greatly reduced the frequency of working mode switching and minimized coal/rock dropping due to adverse road conditions for mining trucks. The operating efficiency was improved by about 30% compared with the conventional method. The proven advantages in stability and adaptability lay a foundation for the energy-saving operation of mining trucks.