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Is it possible to calculate precise speed with LSM6DS3 accelerometer?

VAvag.1
Associate II
 
1 ACCEPTED SOLUTION

Accepted Solutions
Peter BENSCH
ST Employee

Well, an accelerometer can only measure acceleration in different axes. If it moves at a constant speed in a constant direction (linear vector), the acceleration is zero. So you can only measure changes in velocity and calculate a change in position from this by integration, for example, whereby drift effects must of course be taken into account.

But a velocity (speed) cannot be derived from this.

Does it answer your question?

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

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2 REPLIES 2
Peter BENSCH
ST Employee

Well, an accelerometer can only measure acceleration in different axes. If it moves at a constant speed in a constant direction (linear vector), the acceleration is zero. So you can only measure changes in velocity and calculate a change in position from this by integration, for example, whereby drift effects must of course be taken into account.

But a velocity (speed) cannot be derived from this.

Does it answer your question?

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
VAvag.1
Associate II

Hi Peter. Thank You for response.

My aim is to calculate the speed in one direction (x-axis). Movement begins from 0 speed and ends with 0 speed, There are feu speeds (including intermediate 0 speed) that I must distinguish. As You mention, if acceleration is 0, the speed is constant, and it may be not the same as a the beginning. But if the sum of all sampled acceleration values (positive & negative) for particular interval is 0, then we can say that the speed at the end of that interval is same as at the beginning (particularly 0 beginning 0 end). In real life, when I take samples and calculate speed, the graphic have a slope (positive or negative), and it never ends at the same speed as at the beginning, even I take into account Zero-g level. Are some correcting algorithms for it? Sending You 2 graphics, 1-st is simple movement in 2 directions, an the 2-nd is real movement. In both cases real movement stars and stops at 0 speed.