Abstract: A system and method for controlling the swing of a machine is disclosed. The system may comprise a hydrostatic circuit that includes an electronic displacement control pump and a first swing motor fluidly connected in a closed loop circuit. The electronic displacement control pump configured to control the supply of fluid to the swing motor based on a final pump displacement command. The first swing motor configured to rotate the upper carriage of the machine. The hydrostatic circuit configured to control (a) an actual speed of the first swing motor when the final pump displacement command results from a requested swing motor speed and (b) a torque of the first swing motor when the final pump displacement command results from a requested swing motor torque.

Abstract: A system and method for controlling the swing of a machine is disclosed. The system may comprise a hydrostatic circuit that includes an electronic displacement control pump and a first swing motor fluidly connected in a closed loop circuit. The electronic displacement control pump configured to control the supply of fluid to the swing motor based on a final pump displacement command. The first swing motor configured to rotate the upper carriage of the machine. The hydrostatic circuit configured to control (a) an actual speed of the first swing motor when the final pump displacement command results from a requested swing motor speed and (b) a torque of the first swing motor when the final pump displacement command results from a requested swing motor torque.

Abstract: A hydraulic system includes one or more hydraulic pumps, one or more hydraulic motors, a hydraulic tank, and fluid lines. The hydraulic system also includes one or more check valves fluidly connected to the hydraulic pumps and the hydraulic motors. The hydraulic system also includes one or more pilot-operated valves, operably coupled to the check valves by one or more pilot lines. The pilot-operated valves are configured to receive fluid pressure from the fluid lines, opening to allow hydraulic fluid to travel between fluid lines.

Abstract: A valve has a valve body including a main chamber having a first port and a second port, and a main poppet disposed within the main chamber. The main poppet includes a first surface forming a control chamber within the main chamber. The valve has a first passage communicating the control chamber with the first port, and a second passage communicating the control chamber with the second port. The valve also includes a pilot valve having a pilot poppet for controlling fluid flow from the control chamber to the first port through a third passage, and to the second port through a fourth passage, respectively. The valve may further have a feedback spring coupled between the main poppet and the pilot poppet to provide a force relative to a distance between the main poppet and the pilot poppet.

Abstract: Consistent with an aspect of the disclosure, a method for controlling a hydraulic cylinder is provided. The hydraulic cylinder is provided with a chamber and configured to receive fluid from a valve. The method includes receiving a user input and determining a desired velocity of the hydraulic cylinder in accordance with the user input. In addition, the velocity of the hydraulic cylinder is measured and a position of the valve is determined in accordance with the desired velocity of the hydraulic cylinder and the measured velocity of the hydraulic cylinder. The method further includes determining a desired force to be applied to the valve in accordance with a difference between the desired and measured velocities of the hydraulic cylinder, and actuating the valve in accordance with the desired force to thereby inject the fluid into the chamber and move the hydraulic cylinder.

Abstract: A valve for a fluid circuit is disclosed. The valve has a main valve element with a first end and a second end. The main valve element is movable between a flow-passing and a flow-blocking position in response to fluid pressure exerted on the first and second ends. The valve also has a solenoid mechanism operatively associated with the main valve element to move the main valve element toward one of the flow-passing and the flow-blocking positions. The valve further has a main valve spring configured to bias the main valve element in opposition to movement caused by the solenoid mechanism. The valve additionally has a relief valve element configured to communicate a fluid with the first end of the main valve element in response to a fluid pressure to initiate movement of the main valve element.

Abstract: A sensor for a variable displacement pump is provided. The pump has a housing containing a swashplate that is adapted to rotate about an axis. The sensor includes a magnet connected to the swashplate to rotate with the swashplate. A semiconductor chip is disposed proximate the magnet and within the housing. A control is adapted to direct a current through the semiconductor chip and to determine the voltage across the semiconductor chip. The control is further adapted to determine the angle of the swashplate relative to the housing based on the determined voltage.

Abstract: A sensor for a variable displacement pump is provided. The pump has a housing containing a swashplate that is adapted to rotate about an axis. The sensor includes a magnet connected to the swashplate to rotate with the swashplate. A semiconductor chip is disposed proximate the magnet and within the housing. A control is adapted to direct a current through the semiconductor chip and to determine the voltage across the semiconductor chip. The control is further adapted to determine the angle of the swashplate relative to the housing based on the determined voltage.