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 im-prove 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-free-dom dynamics model of articulated vehicle and a mathematical model of pump-controlled electro-hydraulic steering sys-tem were established,including front body longitudinal,lateral,yaw and rear body yaw motion.Based on the yaw velo-city 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 en-sures 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 ac-tion 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 adhe-sion 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 coeffi-cient road conditions for the medium to low speed operation.Meanwhile,based on the experimental conditions of equival-ent 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 steer-ing 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 articu-lated vehicles under low adhesion coefficient road conditions,and the system has not changed the driver's driving experi-ence,and after active control intervention,it can timely,safely,and smoothly hand over the vehicle's driving rights to the driver.
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