Recent content by n00bcake22

Thanks for your replies. Here are the answers to your questions. Also, I have attached a horrible paint drawing of my setup; let me know if you have any other questions. Thanks. Yes, the laser is a rangefinder device. Yes. If the laser is fixed over a surface sample the measurement...

Hello Everyone, Here is my situation: I am using a laser to take distance (height) measurements on a variety of surface types (e.g. mirror, machined surface, plastic, etc.) and I would like to quantify the repeatability of the laser measurements on each surface type. Please note that I care...

Thanks tiny-tim! Converting to Cartesian and back it is! :) Is this the suggested method for all vector operations (dot/cross product, etc.)? Could you give a slightly more verbose example of “bound” and “free” vectors? I am still a bit confused. Using your examples, a force A i^ + B j^...

Hello Everyone, I was just wondering if there was a way to add two vectors that are determined by spherical coordinates (radius, theta, phi). For example, if I have v1 = (5, Pi/4, Pi/2) and v2 = (3, Pi, -Pi/2) is there a way to add these using their respective radii, thetas, and phis or do I...

@Stephen: I think you read my question wrong as your description doesn't match my statement. Lanedance has the correct idea. x = population = N(mu1, sig1) y = measurement of x = x_true + e e = error = N(0, sig2) a = some lower bound, a < mu1 I would like to know the total probability of...

Hello Everyone, My statistics is terribly rusty so I am turning to all of you for assistance! I am in the process of reviewing my old text but I figured this may be quite a bit quicker. Homework Statement Suppose "x" is normally distributed with "mu_1" and "sigma_1." Now suppose x is measured...

It is a through-shaft sensor so I would guess it is intended for both static and dynamic readings. Looking back, my sinusoid equation should be Voltage_Sensor = A*sin(...). I have not measured BOTH the sensor voltage and torque (based on another sensor) as a function of shaft position, just...

@ Stephen: Yes, I did something similar to your error prediction idea. I added boundary lines of +/- 10% to the factory equation and looked for trend/outliers in my recorded data points. Again, not really the statistical "gauge" I'm looking for but it roughly indicates if there may be an issue...

Very interesting point! I believe the torque would be the independent variable in the factory's calibration testing (they want to know the output voltage of their sensor provided a known torque). Maybe they attach an arm of known length and center of gravity to provide the "known" torque? I am...

Oh sorry, the system diagram in the data sheet is just an example the supplier uses. I use a computer to "read" in the voltage and perform whatever calculations are required. I believe each torque sensor shipped has its own calibration equation (which I am guessing they found using regression...

Hey Stephen, sorry it took me a while to respond. Things have been hectic. Anyway, the experiment I run is your described case "2)" and the input torque is VERY repeatable (STDEV < 0.005 inch-pounds, generally). This was measured using a "good" torque sensor. In response to your questions...

Yes. That is the test setup and my situation exactly. The test is quite accurate but likely far inferior to the manufacturer's. Because of this, I used linear regression to calibrate the sensor to my "noisier" setup. Once the test data began falling outside the acceptable limits, however, my...

Ha ha, well my statistics is terribly rusty (and pretty poor to begin with) so I'll try to just explain my intent in general terms and you can offer your thoughts from there. All I am really looking for is a way to see "how well" the factory calibration equation fits/matches/predicts/correlates...

Hello Stephen, Thanks for the reply and this is the situation: I have a torque sensor that comes with factory calibration values for the slope and intercept, "nominal" y1. In the past, however, I have run experiments to gather torque vs voltage data and (through linear regression) obtained my...

Hello Everyone, I was wondering if there is a statistical method to compare two linear equations. I have one "nominal" equation y1=a1*x+b1 and one equation found using linear regression on a data set, y2=a2*x+b2. I know I can just "look" and compare the slope and intercept values but it...