Electronic – accelerometer/gyro combo question


I have a system arm that free-ranges within a certain area. The arm swings, translates and rotates about a vertical axis which sits atop a mobile base. The mobile base can move any direction in the X-Y plane. It's movements are strictly programmed but I would like to start a new version that is semi-autonomous. This new version would need to receive feedback on 3-axis positioning, speed and rotation relative to a fixed point at the edge of the enclosed system (or relative to the position at which it is initialized).
Sensor feedback is completely new to me but I am willing to dive in. Could someone recommend a great starting point for me? Thanks!

Best Answer

What kind of range and accuracy are you looking for?

From a repeated position accuracy standpoint, using a accelerometers and gyroscopes would accumulate errors and drift over time.

Rotary and linear position encoders would probably be the way to go.

If you've opened up a more recent mechanical mouse, you've probably seen the slotted plastic wheel running through the gap of a caliper-like component like this one. You count pulses to keep track of where you are. These are pretty cheap, as long as you have a way of easily making/obtaining the necessary rotary or linear code strip.

There are nicer encoders that cost a bit more. Avago seems to have a bunch of position sensing and motion sensing technologies (led/laser mouse motion detectors, for example).