A method is for controlling an actuation force exerted by an actuating device having a first working chamber and a second working chamber supplied with pressurized air from a source of pressurized air by a first pressure regulator and a second pressure regulator. The method includes calculating, by an optimization algorithm based on a dynamic model of the actuating device and of the first and second pressure regulators, desired values for control signals for the first and second pressure regulators to generate an actuation force equal to a desired value for the actuation force. An estimated value for the actuation force, estimated values for pressures inside the first and second working chambers and for first derivatives of the pressures, are determined by a state observer based on a measured value for the actuation force and on measured values for the pressures in the first and second working chambers.

A system for adjusting actuator pressure on an agricultural implement includes a fluid-driven actuator configured to adjust a position of a tool of the implement relative to the implement frame, with the fluid-driven actuator defining a fluid chamber. Furthermore, the system includes a valve configured to control a flow of a fluid to the fluid-driven actuator. In addition, the system includes a fluid conduit fluidly coupled between the valve and the fluid chamber. Moreover, the system includes a computing system is configured to determine the current position of the tool relative to the implement frame based on the data captured by a position sensor. Additionally, the computing system is configured to determine a current volume of the fluid chamber and the fluid conduit based on the determined current position. Furthermore, the computing system is configured to control the operation of the valve based on the determined current volume.

A sensor system for monitoring a condition of a piston rod includes an interrogator system having a first coil winding coupled to a housing and radially spaced from the piston rod such that a gap is defined between the first coil winding and the piston rod. A second coil winding is coupled to the piston rod and is inductively coupled to the first coil winding. The second coil winding is configured to communicate with the first coil winding through a range of linear movement of the piston rod relative to the housing. A sensor is coupled to the second coil winding. The sensor is configured to measure a characteristic associated with the piston rod and generate a current in the second coil winding to transmit, via the inductive coupling with the first coil winding, an electrical output signal associated with the characteristic to the interrogator system.

A digital positioner for a valve includes a valve controller configured to obtain a set point value for a valve travel of a valve, and generate a pulse-width modulated current signal based on the set point value. The digital positioner also includes a current-to-pressure converter configured to receive the pulse-width modulated current signal from the valve controller, convert the pulse-width modulated current signal to a pulse-width modulated pressure signal, and provide the pulse-width modulated pressure signal to a pneumatic actuator in the valve to adjust a position of the valve.

A hydraulic system includes a first and a second rotating hydraulic machine, the first and second hydraulic machine being arranged to provide a torque via a common output shaft; a first valve arrangement for providing a differential hydraulic pressure level over the first hydraulic machine by using two sources of hydraulic fluid having different hydraulic pressure levels, a second valve arrangement for providing a differential hydraulic pressure level over the second hydraulic machine by using two sources of hydraulic fluid having different hydraulic pressure levels; and a control unit configured to control the first valve arrangement and the second valve arrangement such that different discrete levels of torque are provided via the output shaft of the hydraulic system. A hydraulic system for providing different discrete levels of torque using one hydraulic machine and a plurality of differential pressure levels, and a method for controlling a hydraulic system, are also provided.

A downforce control system for an agricultural ground engaging unit provides individual control of each agricultural ground engaging row unit by providing a proportional pressure control valve connected to the retracting chamber of a double acting cylinder which varies the upward force produced by the retracting chamber of the cylinder against a constant counteracting downward force produced by an extending chamber of the cylinder, the valve control based on a comparison of a sensed resultant downward force on the agricultural ground engaging row unit and a predetermined target downward force.

A drive system with multiple hydraulic cylinders applying torque to the drive shaft of a machine. Each cylinder is attached at one end to the frame of the machine by a clevis that pivots and the other end is rotationally connected to a shaft fixed to a crank arm, fixed to the drive shaft. Each cylinder either pushes or pulls-the crank arm shaft producing torque on the drive shaft in the form of a moment about centerline. As the drive shaft rotates, each cylinder alternately pushes and pulls on the crank arm shaft, depending on the rotational position of the crank arm with respect to the cylinders. The direction of force applied by each hydraulic cylinder is determined by an electro/hydraulic direction control valve, driven by a programmable logic controller, using a signal from a sensor to detect the rotational position of the drive shaft.

According to one embodiment, an actuator includes a plurality of channel members each having at least one first port into which fluid flows and at least one second port from which the fluid flows out. At least one of the channel members includes a different number of second ports from a number of first ports. The channel members are joined with each other to form at least one channel component.

Disclosure herein are hydraulic systems and method of use thereof. The hydraulic systems can include a hydraulic cylinder and a manifold. The hydraulic cylinder can have a first end and a second end. The hydraulic cylinder can include a first port, a second port, and a third port. The first port can be located proximate the first end. The second port cane be located proximate the second end. The third port can be located in between the first port and the second port. The manifold can include a first valve and a second valve. The first valve can be in fluid communication with the first port and the third port. The second valve can be in fluid communication with the second port and the third port.

In one aspect, a system for controlling the supply of hydraulic fluid to an implement may include a pump, a control valve coupled to the pump and first and second fluid lines provided in flow communication with output ports of the control valve. The system may also include a pressure control valve configured to regulate a pressure of the hydraulic fluid being supplied to the control valve such that the hydraulic fluid is supplied to the control valve at a first pressure for raising at least one ground-engaging component of the implement and a second pressure for lowering the ground-engaging component(s). Moreover, the system may include a bypass line in fluid communication with the pressure control valve such that fluid diverted through the bypass line actuates the pressure control valve to adjust the fluid pressure of the hydraulic fluid supplied to the control valve between the first and second pressures.