公开(公告)号：WO2019060136A1

公开(公告)日：2019-03-28

申请号：PCT/US2018/049566

申请日：2018-09-05

Applicant: CATERPILLAR INC.

Inventor： JOHNSON, Sean ,  BITTER, Marcus ,  CUGATI, Sharath

IPC: F15B7/00 ,  F15B21/08 ,  E02F9/22 ,  F15B11/05

Abstract: A closed-loop hydraulic circuit (164) associated with a swing mechanism (105) of a machine is controlled to obtain both a pressure control during acceleration and deceleration of the swing mechanism (105) and a velocity control during coasting. In this manner, a system pressure in closed-loop hydraulic circuit (164) is maintained below a maximum allowable pressure during acceleration and deceleration, and the swing mechanism (105) can be rotated at a desired constant speed during coasting. This is achieved by controlling a hydraulic actuator (142) adjusting the displacement of a variable displacement pump (140) in different control modes, depending on a comparison between a desired displacement of the pump and an actual displacement of the same.