Zengxiong Peng

Study on fuzzy shift control strategy of multi-axles independent driving HEVs based on curve recognition

In this paper, taking a multi-axles independent driving HEV (Hybrid Electric Vehicle) for the study, a model for multi-axles independent driving system was built, a shifting strategy based on throttle and vehicle speed was formulated, and the fuzzy shifting control based on curve recognition was studied. Through fuzzy control methods, a fuzzy shift control system was established to amend shift strategy under curve driving condition. The results indicated that fuzzy shift control strategies based on curve recognition could not only retain the advantages of two-parameter shifting strategy, but also recognize curve conditions and avoid occurrence of unexpected shifting effectively. Vehicle comfort could be greatly improved.

Numerical Simulation and Dynamic Characteristics of Secondary Controlled Hydrostatic Drive

Hydrostatic secondary control is the definition for a variable displacement rotary hydrostatic drive working with constant pressure. The configuration of the standard swash-plate design secondary controlled unit A4VS is introduced. Based on mathematical models of some components such as electro-hydraulic servo valve, positioning cylinder and axis piston unit, the block diagrams of double closed-loop speed control circuit are discussed. In order to research the dynamic characteristics of the secondary controlled hydrostatic drive, the numerical simulation model is established by use of MSC.EASY5 software. The comparative analysis on results of numerical simulation and test for frequency response characteristic demonstrated that the simulation model of the secondary controlled hydrostatic drive is adequately accurate. The influences of load inertia and the PID parameters on the dynamic characteristic of secondary controlled hydrostatic drive are investigated depending on simulating and test.