Research on Speed Control of Unmanned Mine Electric-wheel Dump Truck Considering Time-varying Response Characteristics of Steering System

Abstract

Full hydraulic steering system adopted by mine electric-wheel dump truck is powered by steering hydraulic accumulator and steering hydraulic pump. Its actual steering response ability affected by road surface condition, steering oil pressure and flow, thus, it is a typical large inertia and time-varying execution system. Time-varying characteristics of the steering speed put forward time-varying coordination requirements for the lateral and longitudinal motion which indirectly restricted lateral motion ability of the unmanned mine truck. Speed planning and control without considering steering speed characteristics will result in poor coordination of lateral and longitudinal motion, which will lead to ineffective vehicle tracking. Firstly, this paper analyzes the key factors of time-varying response characteristics of the full hydraulic steering system based on its system principle. Secondly, the constraint of steering speed on the coordination of lateral and longitudinal motion is determined based on the deformation derivation of the truck kinematics model. Finally, combined with the pressure information of the steering accumulator, evaluation model of steering response capability and speed adjustment method in accordance with lateral and longitudinal cooperative constraints are established. Actual test results show that the designed speed adjustment method can achieve good tracking of the mine truck on the continuous limit curve path, with an average lateral error of 0.2 m, and ensure the continuous tracking ability of the mine electric-wheel dump truck on the complex curvature path.

Keywords

• electric-wheel mine dump truck
• steering speed
• time-varying characteristics
• unmanned driving
• cooperative constraint
• speed adjustment