Research On Optimal Adhesion Utilization And Anti-slip Control Of Heavy-haul Electric Locomotives

As the core equipment of railway freight transportation,the optimal adhesion anti-slip control of heavy-haul electric locomotives with high loads and heavy axle loads has always been one of the hot issues in the traction control of heavy-haul locomotives.The so-called optimal adhesion anti-slip control means that under the given external environmental conditions,by controlling the traction motor to affect the adhesion state between the wheels and the rail,the locomotive exerts the maximum traction force that the current rail surface can allow,and at the same time avoids wheel slip.The research of the locomotive's anti-slip control under the optimal adhesion utilization status has significant research value to fully exert the locomotive traction.This paper takes the heavyhaul electric locomotive as the research object,starts from the observation of the wheel-rail adhesion coefficient,and studies the two main problems of the optimal adhesion anti-slip control of the locomotive and the optimization of the optimal adhesion point of the wheel and the rail.The main contributions are as follows:Aiming at the problem that the wheel-rail adhesion coefficient is difficult to obtain during the operation of heavy-haul electric locomotives,this paper proposes an estimation algorithm of wheel-rail adhesion coefficient based on non-singular terminal sliding mode observer.An analysis of the traction motor motion of heavy-haul electric locomotives shows that the load torque of the traction motor and the locomotive adhesion force can be converted.By constructing a non-singular terminal sliding mode observer to observe the load torque of the traction motor,the sensitivity of the traditional full-dimension observer to external parameter changes is reduced,and the wheel-rail adhesion coefficient is further estimated using the load torque observation value.Aiming at the problem that the heavy-haul electric locomotive is sometimes difficult to obtain the optimal sticking point on the uncertain rail surface,this paper proposes an extremum seeking algorithm based on the sliding mode extreme seeking theory for the optimal adhesion point of the uncertainty rail surface.The sliding mode extreme value search algorithm for the optimal adhesion point of the uncertain rail surface proposed in this paper uses the observation value of the adhesion coefficient as the input signal of the extreme value search algorithm,and then designs a series of sliding surface to ensure that the creep speed of the locomotive converges within the tiny neighborhood of the optimal adhesion point.When the sliding mode convergence condition is no longer part satisfied,the oscillatory integration effect is further used to converge,and the search accuracy is improved to reduce the search error.Aiming at the problem that the locomotive wheels are prone to slip when the heavy-haul electric locomotive is in the optimal adhesion state,an optimal adhesion anti-slip control algorithm based on the asymmetrical obstacle Lyapunov function is proposed in this paper.By extracting the creep speed of the locomotive as the state variable,the asymmetrical obstacle boundary of the asymmetrical obstacle Lyapunov function is designed to ensure that the locomotive creep speed is constrained to reliable high adhesive area.The obstacle boundaries in the stable area and the slip area can be independently designed to eliminate the symmetry obstacle limitation,and meet the abnormal utilization of the locomotive in the stable area and the anti-slip targets.Finally,the anti-slip control model of heavy-haul electric locomotives was built by Matlab simulation software,and the proposed control strategy was checked by simulation.And further use RT-Lab semi-physical simulation experiment platform to test the effectiveness of the proposed control strategy.