1
$\begingroup$

I'm trying to sense the position and orientation of an object in real-time using an Arduino. I'm able to measure orientation with ease using a 9-DOF IMU.

I cant seem to figure out how to measure linear position. I tried integrating the linear acceleration readings from the IMU (compensated for gravity) to get velocity then integrating again to get position and using filters at each step. Despite using filters I still get a very inaccurate result.

Unless there's some holy grail algorithm that can extract linear position from an IMU I have to turn to other sensors or devices. Are there any sensors/devices that measure linear position/displacement with respect to an origin (start position).

Does the following device or anything similar to it exist?

Is there such thing as device that has a cable/tether that once pulled measures the displacement based on how far its been pulled out and in what direction? (perhaps by sensing tensile forces/directions on the cable?)

enter image description here

Improve this question
$\endgroup$
3
  • 2
    $\begingroup$ Good imu for position tracking are very expensive. Instead of origin, can you track relative to some beacon? $\endgroup$
    – Abel
    May 18 at 13:50
  • $\begingroup$ Yes, such "draw wire sensors" exist. But where sensors are concerned, context matters a lot and you've given none. Normally use an IMU where no other sensors will suffice because the object has too many degress of freedom. Asking for a draw wire sensor implies your degrees of freedom are very limited. $\endgroup$
    – DKNguyen
    May 18 at 17:01
  • 1
    $\begingroup$ An IMU can augment an absolute position sensor, but as you've just experienced, it can't be an absolute position sensor. There are innumerable ways to do absolute position sensing -- you need to tell us more about what you're doing before we can really help you out here. $\endgroup$
    – TimWescott
    Jun 19 at 20:23

1 Answer 1

Reset to default
0
$\begingroup$

Is there such thing as device that has a cable/tether that once pulled measures the displacement based on how far its been pulled out and in what direction? (perhaps by sensing tensile forces/directions on the cable?)

Yes, a 'linear transducer' or 'string pot' will give you an accurate distance indication, but not the direction. Maybe you can use 2 such devices, to give the distance & angle by triangulation.

Improve this answer
$\endgroup$
1
  • $\begingroup$ Two would give you the location if your gizmo is constrained to a plane, or otherwise has two degrees of freedom. You'd need three for 3D motion. $\endgroup$
    – TimWescott
    Jun 19 at 20:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.