Research on active electrohydraulic steering control of heavy duty articulated vehicles in coal mine based on yaw motion compensation

Due to the use of lumbar folding steering for heavy-duty articulated vehicles in coal mines, the lateral stiffness is weak and the disturbance factors are complex, making it more difficult to operate and easily causing safety problems. A new pump controlled electro-hydraulic steering system with lateral motion feedback compensation was proposed to improve the safe driving and handling performance of coal mine heavy-duty articulated vehicles in wet and low adhesion road environments, and further enhance the intelligent level of coal mine auxiliary transportation. A four-degree-of-freedom dynamics model of articulated vehicle and a mathematical model of pump-controlled electro-hydraulic steering system were established, including front body longitudinal, lateral, yaw and rear body yaw motion. Based on the yaw velocity and lateral acceleration of the decoupling dynamics model, the two-channel articulated steering control strategy of “steering control follow - yaw stability compensation” was designed. The steering control follow channel can realize the real-time tracking of the steering input of the driver by the articulated angle. The yaw stability compensation channel ensures that the actual yaw velocity is close to the ideal yaw velocity by actively adjusting the articulated angle. By setting up a pre-filters and attenuation integrator, an active steering control system was designed, which provides corrective action by adjusting the steering angle to ensure that the vehicle can follow the driver's intention and maintain path following. Based on the dSPACE/DS1007 semi physical simulation platform, some simulation tests were conducted on the low adhesion steering conditions of articulated mining vehicles. The effectiveness of the active controller for tracking the desired path of articulated vehicles was verified by simulating the J-shaped turning condition and selecting the low friction coefficient road conditions for the medium to low speed operation. Meanwhile, based on the experimental conditions of equivalent low adhesion coefficient road surface covered with ice and snow, a 25 t coal mine heavy-duty articulated support truck was used for actual vehicle turning experiments. The results show that the dynamics model of articulated vehicle and a mathematical model of pump-controlled electro-hydraulic steering system established can truly reflect the lumbar folding motion state of this type of vehicle by decoupling the yaw rate and lateral acceleration. The two-channel articulated steering control strategy of "steering control follow - yaw stability compensation" based on the analysis of articulated vehicle yaw stability control, as well as the designed active control system, can effectively improve the lateral stability of articulated vehicles under low adhesion coefficient road conditions, and the system has not changed the driver's driving experience, and after active control intervention, it can timely, safely, and smoothly hand over the vehicle's driving rights to the driver.