200 likes | 435 Views
PROPULSION AND STEERING OF A FLOATING MINI-ROBOT BASED ON MARANGONI FLOW ACTUATION. Karthik Visvanathan, Farah Shariff, Seow Yuen Yee and Amar S. Basu Department of Mechanical Engineering, University of Michigan, Ann Arbor, USA
E N D
PROPULSION AND STEERING OF A FLOATING MINI-ROBOT BASED ON MARANGONI FLOW ACTUATION Karthik Visvanathan, Farah Shariff, Seow Yuen Yee and Amar S. Basu Department of Mechanical Engineering, University of Michigan, Ann Arbor, USA Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, USA 指導教授:劉承賢 教授 學生:劉景文
Outline • Introduction • Literature review • Experiment • Result • Conclusion/future work • Reference
Introduction • Marangoni Flow • The mass transfer along an interface due to surface tension gradient • Liquid with a high surface tension pulls more strongly on the surrounding liquid • Gradient in surface tension will naturally cause the liquid to flow away from regions of low surface tension
Introduction • Example of Marangoni flow - Tears of wine • Alcohol has a lower surface tension than water • This effect is named after Italian physicist Carlo Marangoni • Surface tension gradient can be caused by concentration gradient, temperature gradient, etc. Picture source: www.wikipedia.org keyword : tears of wine
Introduction • Floating mini-robot based on thermal Marangoni flow
Literature review • Steve H. Suhr et al. designed and built the first controllable water strider robot Picture source: “Biologically Inspired Miniature Water Strider Robot” Steve H. Suhr, Yun Seong Song, Sang Jun Lee, and Metin Sitti, Member, IEEE
Literature review • Ming Su designed a floating boat by applying drops of organic solvents to the liquid layer “Liquid mixing driven motions of floating macroscopic objects” APPLIED PHYSICS LETTERS 90, 144102 2007
Literature review • A similar work using isopropyl alcohol as a propellant “Propulsion of microboats using isopropyl alcohol as a propellant” J. Micromech. Microeng. 18 (2008) 067002 (6pp)
Experiment • Water based mini robots for environmental sensing applications and/or military applications • Marangoni flow based on local thermal gradient for propulsion and steering • Compared with solution based propulsion limited fuel may be a challenge • Compared with propeller based propulsion noise and vibration may be a challenge • In a macro system, marangoni flow is usually ignored; but in a micro system, marangoni flow becomes dominant
Experiment • Six legged design provides three DOF of movement • High temperature induces low surface tension, exerting a tangential force to propel the robot
Experiment • Lift force increases with increasing contact angle and saturates at contact angle greater than 90° • To increase lift force leg of the robot can be covered with a hydrophobic material
Experiment • A 10mm x 300μm x 300μm leg with a 2mm x 200μm x 1μm heater • Minimum gap of 10mm between the legs required to prevent temperature gradient from one leg to affect the other
Experiment • At 60℃ for each leg • maximum flow velocity 15.3mm/s • propulsion force 0.638mN
Result • A H-shaped structure was constructed to test the feasibility of the proposed mini-robot • H-shaped robot tested in Fluorinert FC 3283 solution
Result • Linear, clockwise, counter-clockwise motion of the H-shaped structure demonstrated • Spot heated using a soldering iron, the structure was observed to move from regions of lower surface tension (high temperature region) to higher surface tension (low temperature region)
Conclusion/future work • This paper reports a novel propulsion mechanism utilizing a thermal gradient based Marangoni flows • Preliminary experiments demonstrate the feasibility of the proposed propulsion mechanism • The actual proposed device is expected to perform better • hydrophobic material will increase total lift force • propulsion force can be increased by increasing temperature of the heater and the number of legs
Reference • Wikipedia • “Biologically Inspired Miniature Water Strider Robot” Steve H. Suhr, Yun Seong Song, Sang Jun Lee, and Metin Sitti, Member, IEEE • “Propulsion of microboats using isopropyl alcohol as a propellant” J. Micromech. Microeng. 18 (2008) 067002 (6pp) • “Liquid mixing driven motions of floating macroscopic objects” APPLIED PHYSICS LETTERS 90, 144102 (2007)