A servo valve for precisely controlling a position of a pneumatic cylinder does not require a servo amplifier and a small sized and/or high durability servo valve unit. The servo valve comprises a unit body having first and second portions, first and second valve portions, first and second seal members that open and close the first and second valve portions, respectively, first and second drive mechanisms that drive first and second seal members by first and second electric pulses, respectively, a supply flow path between the first end and first valve, an exhaust flow path between the second end and second valve, a common flow path connected to the supply and exhaust flow paths via first and second valve portions, and a drive flow path connected to the pneumatic actuator. First and second drive mechanisms are arranged in a drive mechanism arrangement portion located between first and second end portions.

A machine control system can store model weights determined via machine learning using a training dataset correlating preset hydraulic valve displacements to measured movement parameters of a machine component. The machine control system can receive an input command for the component and machine state data from machine sensors. A control mapping model can use the model weights to map a combination of the input command and the machine state data into a predicted displacement of the hydraulic valve that causes movement of the component in response to the input command.

Provided is an arrangement and a method to detect an oil leakage between a first section and a second section of a hydraulic cylinder. A movable piston is arranged between the first and second section in a way that the piston changes position between the sections. The change in position is done in dependency of a difference between a first force, which acts at the first section on a first cross sectional area of the piston, and a second force, which acts at the second section on a second cross sectional area of the piston. The first section comprises hydraulic oil with a predefined first pressure, while the first force is calculated based on this pressure and based on the first area. The second section comprises hydraulic oil with a predefined second pressure, while the second force is calculated based on this pressure and based on the second area.

A milling machine may have a frame, a milling drum attached to the frame, and ground engaging tracks that support the frame and propel the milling machine in a forward or rearward direction. The milling machine may have height adjustable actuators connecting the frame to the tracks. Each actuator may have a cylinder attached to the frame, a piston slidably disposed within the cylinder, and a rod connected at a first end to the piston and connected to a track at a second end. The milling machine may have a tank storing hydraulic fluid and a fluid conduit connecting the tank to the cylinder. The milling machine may have a control valve selectively controlling a flow rate of the hydraulic fluid in the fluid conduit. The milling machine may also have a controller that determines a height of the frame relative to the ground surface based on the flow rate.

Fault diagnostics utilize an embedded tracking digital twin of a valve assembly physical part in a microprocessor system of the valve positioner. The digital twin has simulation model parameters including a fault-related simulation model parameter. The digital twin receives a control signal representing a real control of the at least part of the valve assembly, and generates simulated measurements relating to the simulated control result. The digital twin compare the simulated measurements with real measurements that relate to the real control result, to track an error between the results of simulated operation and the real operation of the valve assembly to adjust the fault-related simulation model parameter in a sense that the error is decreased. The fault-related simulation model parameter relates to a specific physical fault in the physical part of the valve assembly, and it is detectable and identifiable based on the simulation model parameter adjusted value.

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 work machine (1) comprises at least one structural element (21), at least one pressure medium operated actuator 22) for establishing at least one operation of the work machine, and at least one detection device (23) to determine the position of the structural element (21) of the work machine. An arrangement for controlling at least one operation of the work machine (1) comprises: a control valve arrangement (24) for controlling the actuator (22), and a control device (25) for controlling the control valve arrangement (24). The control device (25) is adapted to control said control valve arrangement (24) for adjusting the pressure and/or volume flow on the return line of the actuator (22) as dependent on the position of the structural element (21).

A speed control system and a power load balance detector for a turbine is provided. The speed control system includes a speed wheel with a plurality of teeth. A timer stores a time stamp when each of the teeth passes by a speed probe. A first speed estimate is determined for overspeed protection, and a second speed estimate is determined for operational speed control. The power load balance detector trips or shuts down the turbine when an unbalance is above a first threshold and the speed of the turbine is above a second threshold.

A hydraulic arrangement for supplying a consumer or actuator includes a first supply device that has at least one pump with an adjustable delivery volume. The hydraulic arrangement further includes a second supply device that is connected in parallel to the first supply device. The second supply device includes a loadable accumulator and a digitally regulated switching valve arrangement.

A vehicle-height control system includes: a fluid supply and discharge device including a compressor configured to suck fluid, and a tank configured to supply the fluid; an actuator-side passage connected to the fluid supply and discharge device; a vehicle-height control actuator provided for a wheel and connected to the actuator-side passage via a vehicle-height control valve; and a vehicle height controller configured to control a vehicle height for the wheel by controlling the fluid supply and discharge device and the vehicle-height control valve to control supply and discharge of the fluid in the vehicle-height control actuator. The vehicle height controller includes a start controller configured to open the vehicle-height control valve after establishing communication between the actuator-side passage and at least one of the tank and the compressor in a state in which the vehicle-height control valve is closed at a start of control of the vehicle height.