Automotive driveline control by a nonlinear nonparametric QFT method

A new nonlinear Quantitative Feedback Theory (QFT) methodology is presented and applied to the control of the automotive driveline with nonlinear clutch and backlash. A driveline model is presented which incorporates the nonlinear clutch characteristics and the coupling backlash realistically sandwiched by compliant inertias. The model gives responses that are representative of typical driveline systems, with the backlash accentuating the magnitude of oscillatory shuffle response. A Nonparametric (NP) identification method is given for directly developing the QFT templates of the Linear Time-Invariant Equivalent (LTIE) plant model set. The identification uses a Discrete Fourier Transform (DFT) to convert the system data to the frequency domain (FD). To mitigate against windowing errors the frequency response (FR) data is locally smoothed by a sliding frequency weighting function. The LTIE set is obtained as set of NP identified models obtained directly from typical vehicle experimental input-output test data. Non-minimum phase (NMP) QFT bounds are determined from the nominal NP plant by determining the Hilbert transform of the NMP plant. The controller design methodology is applied to the model and it is shown that predefined robust tracking and disturbance response performance specifications can be systematically obtained, without subsequent heuristic parameter tuning.