2018-01-1164 Published 0 3 Apr 2018 © 2018 SAE International; Ford Motor Company.Multi-objective Parameter Optimization of Automatic Transmission Shift Control Profiles Vanja Ranogajec University of Zagreb Mirko Coric OptimoRouteJosko Deur University of ZagrebVladimir Ivanovic Ford Motor Company Citation: Ranogajec, V., Coric, M., Deur, J., and Ivanovic, V., “Multi-objective Parameter Optimization of Automatic Transmission Shift Control Profiles,” SAE Technical Paper 2018-01-1164, 2018, doi:10.4271/2018-01-1164. Abstract This paper proposes a method for multi-objective parameter optimization of piecewise linear time profiles for control of Automatic Transmission (AT) shifts and presents results obtained on an example of a powertrain with a 10-speed automatic transmission. The paper first outlines the powertrain dynamics model. Then, the AT control trajectory optimization approach is outlined and employed with the aim of getting insights into the optimal shift control profiles and related performance. The parameter optimization problem is to find parameters of piecewise linear shift control profiles, which provide a trade-off between the shift comfort and performance. The optimization problem is solved by using the multi-objective genetic algorithm MOGA-II incorporated within modeFRONTIER environ - ment. As an extension of the parameter optimization approach, a method for robust parameter optimization is proposed, which aims at ensuring high shift quality and robustness in the presence of transmission actuation param - eter variations. The objective is to find shift control profile parameters that simultaneously minimize mean values of vehicle jerk and shift duration indices as well as their standard deviations for improved robustness against change of trans - mission parameters. The overall optimization approach is demonstrated first on an example of a single-transition power-on upshift, and the obtained optimization results are analyzed and compared to the control trajectory and non-robust parameter optimization results. The analysis points out that the shift robustness can be improved by sacrificing comfort. Finally, the method is applied to a double-transition power-on downshift to illustrate its applicability for more demanding transmission control tasks. Introduction New generation of torque converter automatic trans - missions (ATs) includes a large number of gears for improved fuel economy and vehicle performance [1, 2]. Development of shift control and calibration for those transmissions is challenging due to reconfigurable dynamics associated with a large number of clutch application combi - nations and manifold noise factors such as the actuation errors and delays and related uncertainties or constantly varying operating conditions due to the changing accelera - tion demand by the driver. In order to guide the control system design and calibra - tion process towards the best achievable system performance, different optimization approaches have been proposed in literature. For example, a dynamic-programming- based optimal control is proposed in Ref. [ 3] to derive an analytical feedback and feedforward control law for a single (inertia) phase of a conventional gearshift. In Ref. [ 4], an AT control trajectory optimization approach has been proposed, which is based on the pseudospectral collocation method. This approach gives optimal control inputs (e.g. clutch torque capacity and engine torque reduction) for different shift control cases and with no prior knowledge of control trajec - tories required. However, the obtained optimal shift control trajectories may not be directly applicable in real transmission control system. Namely, in the absence of accurate clutch and engine torque measurements or estimates, it may be very chal - lenging to maintain shift control torques at desired (often complex-shaped) profiles by means of highly nonlinear hydraulic clutch actuators and limited (in terms of precision and r