Modeling and simulation of a hydrostatic transmission with variable-displacement pump

The S-matic power split drive of Steyr Antriebstechnik is a drive box for v ehicular drive systems which combines the advantages of hydrostatic and mec hanical transmission. This paper is concerned with the mathematical modelin g of the hydrostatic unit of the drive box with special emphasis on the swa sh-plate mechanism of the variable-displacement pump. For reasons of reliab ility no measurement device is planned for the variable swash-plate angle. Therefore, a simple discrete on-line simulator for the swash-plate angle is derived by simplifying gradually the mathematical model on the basis of ph ysical considerations. (C) 2000 IMACS. Published by Elsevier Science B.V. A ll rights reserved.