Axial piston pump controller

An axial piston pump having a fixed valve plate and a variable displacement comprising:

• a swash plate having a variable angle of inclination in order to define a displacement of the axial piston pump;
• a solenoid actuator connected to the swash plate, the solenoid actuator configured to control the angle of inclination of the swash plate in order to control the displacement of the axial piston pump;
• and
• an axial piston pump controller configured to:
• determine a displacement of the axial piston pump;
• calculate a pump displacement control current to be supplied to the solenoid actuator to control the displacement of the axial piston pump comprising:
• 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 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 solenoid actuator based on the nominal value and the pump stiffness adjustment factor;
• and
• output an instruction to output the calculated pump displacement control current to the solenoid actuator in order to control the displacement of the axial piston pump.

A method of controlling a displacement of an axial piston pump having a fixed valve plate and a variable displacement comprising:

• estimating a displacement of the axial piston pump;
• calculating a pump displacement control current to be supplied to the axial piston pump to control the displacement of the axial piston pump comprising:
• 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;
• and
• outputting 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.