Constrained control of the synchromesh operating state in an electric vehicle´s clutchless automated manual transmission

This paper considers the constrained control problem of the friction regimes in sliding lubricated surfaces with the purpose of speed synchronization, wear reduction and increasing the lifetime of the friction lining material. The case study here is the engagement process of the synchronizer cone clutch system. Such synchronizer performs the clutchless gear shifting in a 2-speed automated manual transmission (AMT) of an electric vehicle. In the present study, the frictional behavior of the cone clutch system is investigated by considering the involved lubricated friction regimes. By knowing the lubricated sliding friction regimes, the dynamic model of the system is derived according to the variable coefficient of friction. Moreover, the primary sources of the uncertainty and disturbance are recognized and considered in the dynamic model of the system. For the purpose of controlling the system, the control objectives and the constraints are defined, and a controller design method is proposed. The controller design method is based on solving a set of linear programming (LP) problems in the offline phase, which results in a piecewise affine (PWA) feedback law that can be easily applied on the system in the real-time closed-loop configuration. Finally, the performance of the proposed control approach is assessed by presenting the closed-loop control results for the ideal situation as well as the perturbed systems in the presence of the disturbance.