Abstract: For ramp adaptation problem of shift schedule, the approach for multi-performance integrated optimal shift schedule (MPIOSS) for ramp driving of stepped automated transmission vehicle has been investigated. Firstly, the influence of ramp on shifting process is analyzed, and a method to determine the gear range according to the relation between the driving force under various throttle opening and slope resistance is put forward. Secondly, an integrated performance evaluation function is constructed by using the linear weighting method of ideal point and square sum to realize the overall optimization of vehicle power performance and fuel economy under the premise of reflecting the driver's performance expectation. Then, an optimization approach for MPIOSS for ramp driving based on genetic algorithm is proposed, which takes the integrated performance evaluation function as the optimization objective and considers the constraints of ramp driving. The proposed optimization approach is applied to formulate the MPIOSS shift schedules for a 5-speed automated manual transmission (AMT). Finally, the multi-performance integrated optimal shift schedules considering ramp and those ignoring ramp are verified via simulation under fixed throttle and fixed slope, fixed throttle and changing slope, changing throttle and fixed slope, and changing throttle and changing slope conditions. The results show that under the four kinds of ramp driving, the multi-performance integrated optimal ramp shift schedule can eliminate unexpected shift operation and improve the ride comfort. Under the modified HWFET-MTN driving cycle, the fuel economy of the vehicle with multi-performance integrated optimal ramp shift schedules is only slightly lower than that of the vehicle with conventional shift schedule, with a reduction of about 0.8%. Furthermore, power performance simulation under fixed slope shows the proposed MPIOSS for ramp driving can reflect the driver's performance demand intention

Key words: tepped automatic transmission, shift schedule, ramp, multi-performance integrated optimization