# Balancing a plate with an IMU offset from the center

I recently bought a IMU . I am new at this.

My question: Does the positioning of the IMU matter? Are there any differences between placing it at the center of the plate or if it is offset from the center?

Thanks.

• What do you mean by balancing a plate? Balancing it on its side like an inverted pendulum? Balancing it on a ball? – JJM Driessen Oct 11 '15 at 13:57
• I have actuators under the plate to stabilize it. Sometimes the plate is affected by external factors, so I have to correct the orientation to make the plate surface horizontal again. – goddar Oct 12 '15 at 10:41
• So, the plate is horizontal, but it still isn't clear what system you are considering. Proper sensor placement largely depends on the system that you consider and the goal you pursue; a sketch would be appropriate. – JJM Driessen Oct 13 '15 at 12:43
• Hi, sorry for taking too long to reply. I'm still considering to play around with either a tricopter or a pole climbing robot, but I'm still searching for more information. From my research, the sensor is usually placed at the center. It just makes me wonder why aren't there systems with IMU placed off center. – goddar Oct 22 '15 at 10:46

Basically it does not matter.
But you have to be carefull if the plate is rotating fast, because the rotation of the plate around its center point, with the IMU placed out of center, will cause the accelerometer to measure centrifugal forces.

If your task is to stabalize the platform, this won't be an issue for you.

• Owh yes, thats a good point. Thanks. Besides the effect of centrifugal force, do you think vibrations will affect the IMU's readings? I mean, will the IMU still gives out the same readings at the same orientation before and after experiencing vibrations? Of course the imu is calibrated before hand. – goddar Oct 12 '15 at 10:38
• During the vibration-phase the accelerometer might produce non sense. Depends on the amplitude of the vibration. Basically vibrations do not alter the IMU sensor if they are under a certain threshold. You can find this value in datasheets usually. If you hit the sensor with a force which is exceeding the acceleration limit, then the sensor's measurement can be changed. But we are talking about the range of 100,000 m/s² for MEMS. – TobiasK Oct 12 '15 at 11:49