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On the pressure peak minimization in digital hydraulics

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


Original languageEnglish
Title of host publicationThe Tenth Scandinavian International Conference on Fluid Power, May 21-23, 2007, Tampere, Finland, SICFP'07
EditorsJ. Vilenius, K.T. Koskinen
Place of PublicationTampere
PublisherTampere University of Technology
Number of pages15
ISBN (Print)978-952-15-1759-4
Publication statusPublished - 2007
Publication typeA4 Article in a conference publication


Non-ideal on/off valves may cause coincidentally pressure peaks in digital hydraulics. The risk of pressure peaks depends on the coding scheme of the digital hydraulic valve system. Traditional Pulse Code Modulation (PCM) control based on the binary coding has high risk for pressure peaks whereas in Pulse Number Modulation (PNM) control pressure peaks does not occur at all. However, PNM is not yet a solution for pressure peak problem in digital hydraulics due to some technical issues. Instead, Fibonacci coding is a compromise between the above systems and it can ease pressure peak problem in digital hydraulics. Together with coding, controller has also an influence on pressure peaks. Cost function based controller can take into account the risk of pressure peaks in different state transitions and the bad state transitions can be avoided. In this study, a cost function for pressure peak minimization is utilized in a binary and Fibonacci coded valve system based on Separate Meter-In and Separate Meter-out (SMISMO) control. Suitability of different coding schemes is evaluated and the effects of controller parameters on pressure peaks are experimentally studied.

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