Topology and parameter integrated synthesis for design of multi-speed bulldozer automatic transmissions based on graph library

Considering the bulldozer AT gear design method is rare in literature and time-consuming, a fast topology and parameter synthesis method for design of multi-speed ATs with the aid of FGE-based graph library is introduced in this paper. First, all non-isomorphic topology graphs of PGTs with multi-DOF are enumerated. Second, all gears of each PGTs with given number of brakes and clutches are synthesized and the PGTs is transformed into 1-DOF PGTs at different gears in order to derive its gear ratios based on the FGE composition process. A graph library is built based on the FGE composition process. Third, numerous gear ratios of each PGTs are synthesized quickly by identifying their isomorphic structures in the graph library and matching their nodes with those of the isomorphic structures. Compared with traditional method, the calculation time has been greatly reduced and the design efficiency has been improved. Finally, the rational topology schemes are sorted out by completely searching all possible combinations of gear sequences and optimizing their characteristic parameters with NSGA-II. The efficacy and feasibility of the method are verified by comparing the innovative 6-speed bulldozer AT scheme with existing Komatsu scheme.