Caterpillar Global Mining LLC

Caterpillar Inc.

Caterpillar Global Mining Hms Gmbh

Marcus Bitter

Sean Johnson

Sharath Cugati

A digging machine such as a face shovel is controlled in an automated dumping sequence in which the bucket is pivoted to a first angular orientation before opening and, optionally, re-orienting to a second, slightly more forwardly inclined angular orientation. The first orientation may relieve the front part of the bucket from the load while the second orientation is selected to discharge the load at an optimal trajectory. The bucket may move to a third angular orientation before closing the front part against gravity.

Face shovel and method of operation

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

Hydraulic control system and method

A hydraulic control system may include a closed loop hydraulic circuit with at least one hydraulic motor. A plurality of variable displacement pumps may be fluidly connected in parallel in the closed loop hydraulic circuit. A plurality of hydraulic actuators may be configured to adjust the displacement of the variable displacement pumps. A pilot valve assembly may be configured to supply the hydraulic actuators with hydraulic fluid having a pilot pressure corresponding to a desired displacement of the variable displacement pumps. A pressure regulating device may be configured to limit the pilot pressure of the hydraulic fluid supplied to the hydraulic actuators when a working pressure in the closed loop hydraulic circuit reaches a maximum allowable working pressure.

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Dortmund, Germany

Marcus Bitter