Accelerometer capabilities without a gyro - Hopefully a quick answer
Leo.K
Posts: 21
Hi,
I'm working on university final year project to detect and record the movements of a kite flight and display it in google earth.
The initial idea was to use a tri-axis accelerometer (Hitachi H48C) to measure x,y,z movements but I now realise I need a gyro or similar to detect the angles. Otherwise I believe it is impossible to seperate the g component from the forces created by the kite movement as soon as the kite is moving at·a "non-constant" speed.
Now there is no budget left I have been asked to do what I can with the accelerometer. My initial thought was to apply it to a vehicle or similar. The question is,
What am I able to sucessfully·display/measure with the accelerometer? I'd like to at least be able to display forwards and backwards movement plus display any turns, allowing me to plot a route I took. (Start and end location are obtained by GPS) My thoughts are it should be able to do this fairly accurately until it comes to a hill where the g component will shift to the y axis slightly. Am I able to overcome this problem? Is what Im trying to do only possible on flat terrain if at all?
Any help would be much appreciated. I have read and read and read on this but just can't seem to work out if its possible without extra components. Please ask if I am being unclear about anything.
Thank you
Leo
I'm working on university final year project to detect and record the movements of a kite flight and display it in google earth.
The initial idea was to use a tri-axis accelerometer (Hitachi H48C) to measure x,y,z movements but I now realise I need a gyro or similar to detect the angles. Otherwise I believe it is impossible to seperate the g component from the forces created by the kite movement as soon as the kite is moving at·a "non-constant" speed.
Now there is no budget left I have been asked to do what I can with the accelerometer. My initial thought was to apply it to a vehicle or similar. The question is,
What am I able to sucessfully·display/measure with the accelerometer? I'd like to at least be able to display forwards and backwards movement plus display any turns, allowing me to plot a route I took. (Start and end location are obtained by GPS) My thoughts are it should be able to do this fairly accurately until it comes to a hill where the g component will shift to the y axis slightly. Am I able to overcome this problem? Is what Im trying to do only possible on flat terrain if at all?
Any help would be much appreciated. I have read and read and read on this but just can't seem to work out if its possible without extra components. Please ask if I am being unclear about anything.
Thank you
Leo
Comments
2) Think about the physics. What are the forces applied to the accelerometer? How do Newton's Laws apply?
3) You're clearly limited by the resolution of the accelerometer and by the frequency of the measurements. You can't account for movement due to an acceleration that was brief and you missed it or that you miscalculated due to limited accuracy and limited resolution in time. Eventually, these errors accumulate and affect your estimated position and velocity.
4) You can't really measure angular velocity or acceleration without a gyro. If you don't have some idea of the orientation of the accelerometer, you won't know how to apply the measured accelerations.
Thanks very much for your reply. I'm very sorry for the multiple posts. I realised the second section existed after I posted the first. I thought I'd be able to remove the first post but I couldnt see how. I will look again or request the removal of this post as I believe the sandbox is probably the more appropriate section. And sorry again. I do understand the nuisance of people multi-posting.
Please could you help me/reply in the sandbox? It would be much appreciated.
I have added a little more info to the sandbox section. Please could you see if you can help? I think your point 4 may answer my question but I'm not sure.
Thank you very much for sharing your expertise,
Leo
I hope this helps. There is a skate board application in the parallax text book smart sensors and applications.
http://www.parallax.com/Portals/0/Downloads/docs/prod/sic/SmartSensors-v1.0.pdf
Stephen Wagner