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RRA kinematics

Posted: Wed Nov 15, 2017 2:28 am

by julian_atkinson

Hi there

I have plotted a comparison of the kinematics for IK vs RRA vs CMC.

I see a phase shift in the kinematics produced by RRA. Also, the kinematics from RRA is subsequently fed into CMC, but the CMC matched IK better than RRA.

Can anyone offer any insight as to why RRA has this phase shift around 65% of gait?

: j.jpg (189.5 KiB) Viewed 868 times

Thank you
regards,
Julian

Re: RRA kinematics

Posted: Tue Nov 21, 2017 3:10 pm

by jimmy

My first instinct seeing these plots is that it is a reporting issue. RRA uses a variable step size integrator so there is no guarantee that you will have the same number of frames as the input kinematics. For reporting, you will need to spline the rra kinematics to have linear rate.

Re: RRA kinematics

Posted: Thu Nov 23, 2017 2:30 am

by julian_atkinson

Thank you for your response James.

The results of all three functions have been resampled for this figure. This was done using the interp1 function in matlab, with the 'pchip' setting which is a shape-preserving piecewise cubic interpolation.

regards,
Julian