Caterpillar Inc.

Caterpillar Sarl

Arick M Bakken

Paul John Cairns

Fuaad Sayeed

Niall Hugh McNamee

William Christopher Swick

An axial piston pump controller for an axial piston pump having a fixed valve plate and a variable displacement is provided. The axial piston pump controller is configured to determine a displacement of the axial piston pump, and to calculate a pump displacement control current to be supplied to the axial piston pump to control the displacement of the axial piston pump. Calculating the pump displacement control current comprises calculating a nominal value for the pump displacement control current based on a rotational speed of the axial piston pump, calculating a pump stiffness adjustment factor based on a pump stiffness control map having as inputs: an output pressure of the axial piston pump; and the estimated pump displacement, and calculating the pump displacement control current to be supplied to the axial piston pump based on the nominal value and the pump stiffness adjustment factor. The controller is further configured to output an instruction to output the calculated pump displacement control current to the axial piston pump in order to control the displacement of the axial piston pump.

Axial piston pump controller

The present invention refers to a method for generating a control command to at least one actuator of an electrohydraulic machine, comprising a step of receiving and monitoring an input signal provided by a user interface, a step of determining if the monitored input signal is related to a user-induced input or a non-user-induced input, and a step of generating the control command upon processing the input signal in dependence on whether the input signal is a user-induced input or a non-user-induced input.

Method and control unit for generating a control command to at least one actuator of an electrohydraulic machine

An excavator or other work machine includes a tilting bucket operated by a hydraulic actuator controlled by a bucket control valve responsive to control signals including a bucket shake control signal, which causes the bucket to move repeatedly in the rack and dump directions to shake debris from the bucket in a bucket shake operation. The actuator is powered by pressure from a hydraulic pump, and a control system includes an unloader valve to relieve pressure from the supply line to unload the pump when there is no demand for power. The control system is arranged to maintain a constant pressure signal in a load sensing line, to maintain the unloader valve constantly in a closed condition, for the duration of the bucket shake operation. This may be achieved by pressurising an actuator of a quick coupler to lock the bucket to the machine.

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Broughton Astley, United Kingdom

Arick M Bakken