Differential folding steering control strategy of mining vehicle articulated system based on multi-loop nesting

JI Zhiyong; WU Zhongbin; REN Zhiyong; ZHANG Ruiliang; WANG Tie

doi:10.13225/j.cnki.jccs.2024.0466

Abstract：There is a hysteresis of articulated vehicles when they follow the folding motion,and their steering characterist-ics may also show non-linear characteristics under specific operating conditions.To further improve the handling perform-ance of articulated steering vehicles,a double closed-loop structure of position and velocity is adopted to collaboratively control the folding process,and real-time compensation of the followed target is carried out according to the yaw motion error.On this basis,a differential folding steering strategy based on multi-loop nesting is proposed for the differential steering configuration.An 8-DOF nonlinear dynamics model of the articulated mining vehicle containing the horizontal motion of the front and rear bodies and the rotational motion of the wheels is constructed,and the position and velocity closed-loop control parameters of the system are determined through the time-domain analysis of the folding steering pro-cess.The crossover frequency,phase delay,and bandwidth distribution of the follow-up folding system under the single-loop and double-loop control are comparatively analyzed based on the frequency characteristics of the controllers.In the input of the position loop,i.e.the calculation of the folding reference position,the driver's desired folding position is posit-ively compensated based on the actual yaw motion deviation of the vehicle body,where the reference point of the yaw ve-locity is obtained by real-time computation of a linearly discretized 8-DOF differential steering model,thus forming a multi-loop nested structure.Based on the MATLAB/Simulink numerical simulation platform and the articulated steering proportional prototype experimental platform of the distributed electric driven,the folding steering control strategy is veri-fied.The results show that,on the good road surface,compared with the original single-loop control,the folding angle rise time of the multi-loop nested control strategy is reduced by 56.8％,50％,and 51％,respectively,in the step steering test of 5°,10°,and 15°,and the phase delay is reduced by 75.6％,80.4％,and 75.4％,respectively,in the sinusoidal steering angle input test with the amplitude of 10°,20°,and 30° and the frequency of 0.8 Hz.The system bandwidth is increased while the steering is stabilized.In the test on low adhesion road,the multi-loop nested control strategy can reduce the lateral pos-ition deviation of the vehicle by 56.8％,and the phase deviation of the yaw velocity by 40.3％,which shows better traject-ory tracking capability than the single-loop control.