Method and apparatus for controlling a hydraulic system of a work machine

A work machine for performing work with an attachment, comprising:

• an engine;
• a throttle configured to provide a throttle position signal for setting a speed of said engine;
• a hydraulic system including an engine-driven hydraulic pump and a hydraulic valve arrangement, said hydraulic system being configured to hydraulically actuate said attachment via said hydraulic valve arrangement;
• an operator command input device configured to provide an operator command signal for directing a motion of said attachment;
• and
• a controller, said controller including:
• a memory storing a first predetermined correlation between said operator command signal and a corresponding command flow rate from said hydraulic valve arrangement, said memory also storing a second predetermined correlation between said throttle position signal and a corresponding available flow rate from said hydraulic pump;
• and
• a processing unit communicatively coupled to said memory, said throttle and said operator command input device, wherein said processing unit is configured to execute program instructions to:
• receive said operator command signal from said operator command input device;
• receive said throttle position signal from said throttle;
• retrieve from said memory said first predetermined correlation and said second predetermined correlation;
• determine said command flow rate based on said first predetermined correlation and said operator command signal;
• determine said available flow rate based on said second predetermined correlation and said throttle position signal;
• and
• provide a control signal to said hydraulic valve arrangement based on said available flow rate and said command flow rate.

A controller for controlling a hydraulic system, said hydraulic system including an engine-driven hydraulic pump and a hydraulic valve arrangement controlled in response to an operator command signal from an operator command input device, wherein a speed of said engine is set based on a throttle position signal from a throttle, comprising:

• a memory storing a first predetermined correlation between said operator command signal and a corresponding command flow rate from said hydraulic valve arrangement, said memory also storing a second predetermined correlation between said throttle position signal and a corresponding available flow rate from said hydraulic pump;
• and
• a processing unit communicatively coupled to said memory, said throttle and said operator command input device, wherein said processing unit is configured to execute program instructions to:
• receive said operator command signal from said operator command input device;
• receive said throttle position signal from said throttle;
• retrieve from said memory said first predetermined correlation and said second predetermined correlation;
• determine said command flow rate based on said first predetermined correlation and said operator command signal;
• determine said available flow rate based on said second predetermined correlation and said throttle position signal;
• and
• provide a control signal to said hydraulic valve arrangement based on said available flow rate and said command flow rate.