Hello !
I want to create a device that measures the initial angle at which someone jumps forward.
I have tried using an MPU6050 but I can't extract any results since I cannot know the angle of the sensor with respect to the ground to use the acceleration values.
How can I do that (without requiring an initial reference/calibration point)?
Thank you very much in advance.
Exactly how do you define that angle?
If I understand well, you would get
tan(alpha) = upward velocity/forward velocity
Where alpha is your corner. This equation is easily solved
Problem is that your sensor measures acceleration, not velocity.
Velocity can be calculated from acceleration if velocity is known at t0.
But the error will increase in time...
And your object (a runner?) will not move smoothly.
So you need another approach to measure velocity in 2D. And I do not have an idea for you... sorry
At the shoes. It's the arc tangent of the lateral force divided by the vertical force (G+a) at the instant of takeoff. Needs some refinement, but...
Two completely different opinions from the forum, of course, but what I wonder is how the OP defines the takeoff angle.
Well, same formula and something that you actually can measure.... with the proposed sensor
Let OP decide...
At the shoes will not be easy. Acceleration of one shoe will be zero..
You could measure resulting acceleration at the centre of gravity. That will be near the belly button...
it does seem hard to define. my proposal assumes zero rotational inertia
(launch force vector intersects the COG at the instant of take off).
but yes, lots of feedback needed here from the OP.
Hello, thank you very much for your responses.
It seems I did not define the problem very well.
That's what I am talking about.
If I could actually ensure that the MPU6050 is always horizontal to the ground then the angle would be arctan( z acceleration/x acceleration). The issue is that I cannot know the angle of the sensor itself.
Have you noticed that the accelerometer also measures g, the acceleration due to gravity?
For ballistic trajectory calculation in the xz plane, the takeoff angle is usually defined from velocity, as atan2(vz, vx) at t=0, the instant of launch.
if the imu package was placed on a gimbal and the gimbal was kept orientated to the center of the earth, the center of the Sun and level, the imu package orientation could be known at all points of movement.
Heck the movement measurements from the IMU could be used for various metrics as well as keeping the platform orientated.
That sounds challenging.
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