Ideas needed! Measuring displacement on two axes, but can I measure the displacement on the different axes over one direction instead?
Hello fellow engineers!
A few weeks back I started a thread on different methods of translating horizontal and vertical displacement over one axis (the vertical one) so I could use some sort of displacement sensor above water to calculate strain on these axes in water.
TLDR: I am using two linear inductive proximity sensors on two axes, but the one that measures horizontal displacement does not fit in it's circular housing because it is perpendicular to the axle, so I need to find a way to fit both of these sensors in the housing while still being able to measure displacement over both axes. (And, if it doesn't properly fit in the housing it will disturb the flow of water through the tank, and thus negatively impact my measurements)
Today I'm here with a similar issue, sadly, even after I thought I had the solution for the first problem. I'll elaborate.
So, my initial task was to redesign a system that measures lift and drag forces on a wing, inside a circular tank with about 500 Liters of water. The wing is attached to a fixed clamp, and this clamp is fixed to a centered rotor that spins the wing around at constant speed, around a relatively low-ish Reynolds number (speeds of 0 - 2 m/s). The way we are going to measure lift and dragforces will be through displacement of the horizontal and vertical axes (see picture one). This is achieved by decoupling or uncoupling the total force over two axes, vertical for lift, horizontal for drag. The small displacement of these axes can be measured through a multitude of sensors, but, since we are measuring these forces in water (not in air, because then our scales would be impractically gigantic), a lot of them can't actually be used. I turned my attention to inductive proximity sensors, not switches, as these often come with industrial grade sealing/protection from the elements (I'm aware of other water proof sensors on the market, been doing a lot of research on them lately and IPS seem most suitable for my application). I will place one sensor above each moveable ring, so one parallel to the vertical axle to measure lift displacement, and one parallel to the horizontal axle to measure drag displacement.
The problem lies in the placement of the horizontal sensor (see the red circles in picture 2 and 3). I simulated the current idea in SolidWorks and it turns out the horizontal sensor is actually much too long, so it will poke out of its circular encasing. Why is this a problem, you may ask? That is because the sensor that is sticking out from its perfectly circular hub, will create a disturbance in the flow of water in the tank, which in turn will negatively influence the accuracy of our measurements. Of course, I could just enlarge everything, as in, make the rod of the wing longer so I can make the circular encasing wider as well, to fit everything in but, this will distort the currently very delicate displacement, and indirectly impact the precision of my sensor. The displacement I'm going to be measuring won't exceed 2mm, and my sensors are catered to that too, so if I increase sizes all around I will have to purchase two different sensors probably (> €250).
So I'm faced with this problem: My horizontally placed sensor is too long, and a way of fixing this would be by placing this sensor vertically also, but then the question would be how to translate the horizontal displacement to a vertical axis... Sadly I didn't grow up in a workplace, so I have very limited knowledge of practical solutions some of you might see as easy, or go-to.
I'd love to hear your thoughts on this matter! Maybe I'm just overlooking something very basic, but please don't hold back on any ideas you have, I can only learn from this!
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