[Ether]

Originally Posted by Invictus3593

Using trapezoidal integration, would that eliminate the errors?

Not with the accelerometer and gyro that come in the KoP. They're not accurate enough. The problem is the double integration (to get from accel to position). The small errors in the accel and gyro signal get integrated. The errors accumulate. After a short period of time, your computed position drifts away from your true position. The gravity problem Greg mentioned also contributes to errors in the accel signal in the plane of interest (the floor).

Haha, he gave the ac = (Vt2)/r equation to use in the case that we were turning, which would throw off our real location; I guarantee you I don't drive in circles!

The method I described applies to 2D motion in the plane of the floor, so it applies to turning (be it circular or not) as well as linear motion. The a=v²/r is not required.

If we updated the rotational acceleration every 10ms and took the average acceleration for that period, do you think would this be a short enough interval to be able to plot location semi-accurately?

You can answer this question by simulating a simple example in Excel or LabVIEW or Maxima or Octave or SciLab or any CAS tool or programming language of your choice. Assume you have a vehicle traveling in a perfect circle of radius R at a constant speed S. Then you know what the true ax and ay components of the acceleration are at any point in time. Do the numerical integration using those perfectly correct numbers. You should get almost perfect circular motion. Now introduce a small error into those ax and ay numbers, to reflect errors expected in the KoP gyro and accelerometer, and do the integration. You'll probably get something like a spiral instead of a circle.

I've read that with robotic probes that go into caves and such, they use this kind of plotting system, an accelerometer and a gyro

I don't know about the probes you are referring to, but if they use only an accelerometer and gyro to compute position they're probably much more expensive (and accurate) than those in the KoP.

Or is there anther way to do it without the problems you describe?

Placed properly, 3 unpowered omni follower wheels, each with an encoder, could theoretically be used to compute both position and rotational orientation -- without the need for a gyro or accelerometer. That would have a different set of problems.