Circuit arrangement for position and feed control of a hydraulic cylinder
AssigneeMannesmann Rexroth GmbH
InventorJoachim Neumann
Life of this patent
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Abstract
The object of the invention is to improve the position and feed or advance regulation of a hydraulic drive which is controlled by a proportional valve. In a first compensation circuit the flow characteristic of the proportional valve is linearized to obtain very small feed rates and a high control amplification. In a second compensation circuit the positioning error of the drive arising from the necessary overlapping of the proportional valve is compensated.
Claims10
A control circuit which is part of an arrangement for position and feed control of a hydraulic cylinder, the arrangement having a proportional valve with an overlap in its neutral position in which its passages close before the valve is fully in the neutral position for controlling fluid paths between the cylinder and a fluid source and a tank, the control circuit comprising:
- means for generating a control signal from a deviation between a common variable and a controlled variable,
- a first compensation circuit for generating a position compensation signal when said proportion valve approaches the overlapping position,
- means for summing said position compensation signal and said control signal, and
- amplifier means for communicating an operating signal to said proportional valve in response to a summation of said position compensation signal and control signal, the operating signal directing the proportional valve to retain a remaining cross-section of said proportional valve opened before reaching its overlapping condition and until the control deviation is zero.
Dependencies are inferred from the claim text.