This project addresses these two needs by introducing the concepts of instability and passivity in the design of electrohydraulic valves. Firstly, a new class unstable single stage valves (which are inherently cheaper and more reliable than multistage valves) with improved performance will be developed. By intentionally making the spool unstable, spool agility and hence bandwidth, can be enhanced by the unstable flow forces. Secondly, a new class of electrohydraulic valves that possess a passivity property will be developed. Although passivity is well recognized to improve safety and to enhance human friendliness, it has not been previously exploited in electrohydraulic systems.
Theory for the design and control of the new unstable valves and passive valves will be developed. The new valves will be prototyped. The unstable valves will be demonstrated in typical force and position tracking tasks. The usefulness of the passive valves in safety critical, human operated applications will be demonstrated in the context of a hydraulically actuated teleoperated surgical tool.
This research will enable hydraulic systems to be more cost effective,
more reliable, have better performance, and to be safer and more user friendly.
These advances will expand hydraulics into a larger segment of industry
and to new applications.
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