System Evaluation Method for Two Planetary Gears Multi-mode Hybrid Powertrain under Gray Relational Analysis Based on Fuzzy AHP and Entropy Weight Method 2020-01-0430
Millions of configurations of power-split hybrid powertrain can be generated due to the variation in number of planetary-gear sets (PG), the difference in number, type and installation location of shift actuators (clutches or brakes), and the difference in connection positions of power components. Considering the huge number of configurations, complex structures and control modes, it is vital to construct an appropriate multi-index system evaluation method, which directly affects the requirement fulfillment and the time and cost of 2-PG system configuration design.
Considering one-sidedness (dynamic and economic performance), simplicity (linear combination of indicators) and subjectivity (relying on expert experience) of previous system evaluation method of 2-PG hybrid system design, a more systematic evaluation method is proposed in this paper.
The proposed evaluation system consists of five categories, involving dynamic, economy, comfort, reliability and cost, and more than 20 indicators. To reduce the influence of the different experts' subjective opinions and the one-sidedness of objective data, a comprehensive system evaluation method based on fuzzy analytic hierarchy process (FAHP), entropy weight method (EWM) and grey relational analysis (GRA) is put forward. The consistency of subjective judgment and evaluation results is enhanced by FAHP; the objectivity and rationality are enhanced by EWM based on huge sample data of feasible 2-PG system configurations; finally, the best configuration is obtained via sorting using GRA.
The system evaluation method proposed in this paper combines the advantages of three evaluation methods. The calculation process is simple and the evaluation results are intuitive. It provides a new evaluation method for power-split hybrid system design.