Energy Efficient Control of a Discrete Displacement Multi-Chamber Cylinder
Translated title
Energibesparende Kontrol af et Multikammer Cylinder med Digital Hydraulik
Author
Joensen, Teitur
Term
4. term
Education
Publication year
2023
Submitted on
2023-03-14
Pages
60
Abstract
Dette projekt modellerede og styrede vinklen på en gravemaskinearm drevet af en digital hydraulisk aktuator: en hydraulikcylinder med flere kamre og tænd/sluk-ventiler, der kombinerer faste krafttrin (i stedet for kontinuerligt justerbare proportionale ventiler). Vi opbyggede en Simulink-model af systemet og designede tre PID-regulatorer til at positionere armen. Fordi digital hydraulik kun kan anvende foruddefinerede kraftkonfigurationer, udviklede vi en kraftskiftealgoritme (Force-Shifting Algorithm, FSA), som over tid vælger ventilkombinationer for at opnå den ønskede bevægelse. Hovedmålet var at øge energieffektiviteten. Vi afprøvede to tiltag: (1) at gøre FSA’ens samplingtid langsommere, så den skifter sjældnere mellem konfigurationer, og (2) at indføre en låsemekanisme, som holder armen på sit mål og dermed undgår små frem- og tilbage-oscillationer. Låsemekanismen reducerede energiforbruget, mens en langsommere samplingtid for FSA’en øgede energiforbruget. Resultaterne peger på, at aktiv låsning er mere lovende for effektiviteten end blot at reducere skiftefrekvensen i denne digitale hydrauliske løsning.
This project modeled and controlled the angle of an excavator arm driven by a digital hydraulic actuator: a multi-chamber hydraulic cylinder with on/off valves that combine fixed force levels (rather than continuously adjustable proportional valves). We built a Simulink model and designed three PID controllers to position the arm. Because digital hydraulics can only apply preset force configurations, we developed a Force-Shifting Algorithm (FSA) that selects valve combinations over time to achieve the desired motion. The main goal was to improve energy efficiency. We tested two ideas: (1) slowing the FSA sampling so it switches between configurations less often, and (2) adding a locking mechanism that holds the arm at its target to avoid small back-and-forth oscillations. The locking mechanism reduced energy consumption, while a slower FSA sampling time increased the system’s energy use. These results suggest that active locking is more promising for efficiency than simply reducing switching frequency in this digital hydraulic setup.
[This summary has been rewritten with the help of AI based on the project's original abstract]
Keywords
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