Robert Boschgmbh

Norrhydro Oy

Tuotekehitys Oy Tamlink

Matti Linjama

Lauri Siivonen

Kalevi Huhtala

Ari Sipola

Matti Vilenius

Jyrki Tammisto

Mikko Huova

Hannu-Pekka Vihtanen

Arto Laamanen

Heino Foersterling

Edgar Stamm

An apparatus comprising: a series of units, each being capable of producing a volume flow; a first channel for supplying hydraulic fluid into the apparatus; a second channel for supplying hydraulic fluid from the apparatus; a first series of valves comprising at least one controlled valve for each unit; a third channel for supplying hydraulic fluid from the apparatus; and several controlled auxiliary valves, each being provided for one unit. The control circuit also comprises: at least one actuator for converting hydraulic energy to mechanical energy, wherein said actuator is at least connected to either the second channel or the third channel; and a control device configured to synchronize the operation of the valves of the first series of valves and said auxiliary valves with the operation of said units, and to control the actuator by means of pressure and volume flow. In the method, the operation of the first series of valves and said auxiliary valves is synchronized with the operation of said units, and controlling the pressure and the volume flow in a predetermined manner, for controlling one or more actuators by means of a control device.

Apparatus, a control circuit and a method for producing pressure and volume flow

In a method for controlling a valve system controlling an actuator, the first direction of motion of the actuator is controlled solely by the first and the second valve series; or, its second direction of motion is controlled solely by the third and the fourth valve series; and an error caused by a fault situation in the control of the actuator is compensated for by using, for the control of the first direction of motion, also the third valve series, the fourth valve series, or both of them; or, an error in the control of the actuator caused by a fault situation is compensated for by using, for the control of the second direction of motion, also the first valve series, the second valve series, or both of them. In the method, for searching for faults in the valve system controlling the actuator, the pressure of the inlet port of the valve system, the pressure of the first working port, and the pressure of the outlet port are determined; one or more valves of the first valve series and one or more valves of the second valve series are opened; the measured pressure of the first working port is compared with a situation corresponding to a system operating correctly; and on the basis of the comparison it is concluded whether the single valve is faulty or not.

Detecting of faults in a valve system and a fault tolerant control

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Valkkinen, Finland

Matti Linjama