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 method and apparatus for controlling the motor output speed of a variable displacement hydraulic motor are disclosed. The method may include determining a value indicative of a motor output speed, determining a value indicative of a desired motor output speed, determining a desired position of a control valve using a nonlinear feedback control law, and, controlling the motor output speed as a function of the control valve position, wherein the nonlinear feedback control creates a first order system response.

Abstract: A method and apparatus for controlling the motor output speed of a variable displacement hydraulic motor are disclosed. The method may include determining a value indicative of a motor output speed, determining a value indicative of a desired motor output speed, determining a desired position of a control valve using a nonlinear feedback control law, and controlling the motor output speed as a function of the control valve position, wherein the nonlinear feedback control creates a first order system response.

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 method and apparatus for controlling a variable displacement hydraulic pump having a swashplate pivotally attached to the pump. The method and apparatus includes determining a desired swashplate angle as a function of a power limit of the pump, determining an actual swashplate angle, determining a value of discharge pressure of the pump, moving a servo valve spool to a desired position as a function of the desired swashplate angle, the actual swashplate angle and the discharge pressure, and responsively moving the swashplate to the desired swashplate angle position.

Abstract: A method and apparatus for controlling a variable displacement hydraulic pump having a swashplate pivotally attached to the pump. The method and apparatus includes determining a desired swashplate angle as a function of a power limit of the pump, determining an actual swashplate angle, determining a value of discharge pressure of the pump, moving a servo valve spool to a desired position as a function of the desired swashplate angle, the actual swashplate angle and the discharge pressure, and responsively moving the swashplate to the desired swashplate angle position.

Abstract: An apparatus and method for controlling a discharge pressure of a variable displacement hydraulic pump. The apparatus and method includes a swashplate pivotally attached to the pump, a control servo operable to increase an angle of the swashplate relative to the pump, a biasing servo operable to decrease the angle of the swashplate relative to the pump, a servo valve having an output port hydraulically connected to the control servo, a divertor line having a first end connected to the pump output port and a second end connected to the biasing servo, and means for controlling the servo valve as a function of the discharge pressure of the pump.

Abstract: An apparatus and method for controlling a discharge pressure of a variable displacement hydraulic pump. The apparatus and method includes a swashplate pivotally attached to the pump, a valve plate located on the pump to allow hydraulic fluid to enter the pump through an intake port on the valve plate, and to exit the pump through a discharge port on the valve plate, the hydraulic fluid entering and exiting the pump responsively creating a pressure carry over angle &ggr;, a control servo operable to control an angle of the swashplate relative to the pump, a servo valve having an output port hydraulically connected to the control servo and an input port hydraulically connected to the pump output port, and means for controlling the servo valve as a function of the discharge pressure of the pump and responsively balancing a torque induced by the pressure carry over angle &ggr; with a torque generated by a control pressure Pc at the control servo.

Abstract: A method and apparatus for controlling a pump discharge pressure of a variable displacement hydraulic pump having a swashplate, and a servo valve for controlling an angle of inclination of the swashplate. The method and apparatus includes sensing a value of an actual pump discharge pressure, determining a desired control pressure using a first feedback linearization control law, determining a desired servo valve spool position using a second feedback linearization control law, and controlling the value of the actual pump discharge pressure as a function of the first and second feedback linearization control laws.

Abstract: Apparatus for spacing consecutive capsules of solid material traveling as a capsule train in a pipeline in which the capsules are carried by a fluid flowing through the pipeline includes a separation system interposed between upstream and downstream portions of the pipeline for receiving the train of capsules. The separation system passes consecutively separated capsules within the capsule train to the downstream portion. The separation system is constructed for increasing the spacing between consecutive capsules within the capsule train in the downstream portion of the pipeline after passing through the separation system. The volume of fluid flowing from an outlet location of the separation system is substantially the same as the volume of fluid flowing into an inlet location of the separation system.