Development of a Plastic 3D Printed Valve for Small-Scale Electrohydrostatic Actuator Applications
Bibliographic record
Abstract
Electrohydrostatic actuators (EHA’s) are well-known for their high power densities (ratio of actuator weight to actuator power) and good dynamic performance. While EHA’s dominate in high-power systems, lower-powered systems (< 100W) typically employ electromechanical type actuators, such as screw actuators, due to the unavailability of low-cost hydraulic components on an appropriate scale. Recently, the radio-controlled hobby industry has started producing small- scale hydraulic pumps and cylinders for model construction equipment. These hobby grade pumps and cylinders may be repurposed in an EHA configuration for use in more demanding applications but limiting this is the fact that no appropriate method of handling the unbalanced cylinder flows of a typical single-rod cylinder exist. An inverse shuttle valve is a simple and efficient solution to compensate for this mismatch of cylinder flows, and the recent progression of 3D printed plastics enables such a valve to be produced for a very low cost. This thesis develops the small-scale 3D printed plastic inverse shuttle valve concept and improves upon prototypes developed within the Fluid Power Research Group at the University of Saskatchewan. Presented in this thesis is a wide variety of experiments investigating and improving the performance potential of such a 3D printed inverse shuttle valve in a small-scale EHA application. The sealing capabilities of 3D printed plastic poppets and the effects of print orientation, surface lapping, valve size, fluid pressure and sealing time were experimentally assessed. The pressure drops of the flow paths in a prototype design were measured and reduced by an informed selection of tubing and fittings. Finally, a series of experiments explored the steady state, dynamic response, and thermal performance of an EHA designed with the newly developed inverse shuttle valve. Satisfactory poppet sealing performance was obtained by utilizing a lapping procedure to smooth the sealing surfaces and selecting sealing element geometries insensitive to misalignment. A low- restriction flow path between the pump and valve was identified to improve power efficiency and reduce the potential for pump cavitation. Testing of the EHA revealed impressive performance, with high force and velocity capabilities, good energy efficiency, and very fast dynamic responses. These results satisfied the research objectives, demonstrating that the use of a 3D printed inverse shuttle valve in a small-scale EHA system is a viable concept.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".