Notebook Entry

Today's task list:

  • [x] Motek training, Day One
  • [x] Work on parsing the walking data
  • [] Make generic settings on the lab website
  • [] Work on the website theme
  • [] Fix the budgeting and purchasing issues
  • [] Review the TODO items on the Yeadon paper
  • [] Run variations in guesses for structural id
  • [] Work on BMD papers

Motek Training

The Lua scripting environment.

D-Flow Feature Requests

  • feature request: output mox files to hdf5 instead
  • support python alongside of lua because of the abundance of scientific code
  • allow scripting outside the d-flow loop, ie.e start stop the loop, init code outside of it
  • include the Lua interpreter in the script module window for interactive debugging
  • Allow Lua scripts to be run and debugged outside of D-Flow
  • Introduce extensive keyboard shortcuts for interacting with modules.


  • Any top layer D-Flow related window does not gt hidden when you select windows that are behind it.

Walking System Identification

Ton's idea is to identify both the phase dependent gain matrix and the "commanded" gait cycle. I didn't understand the idea about identifying the commanded gait cycle (angles and rates) and still don't know if I understand what it means conceptually. But I think the problem now becomes non-linear.

\[m(t) = K(t) [s_{lc}(t) - s(t)]\]

If we measure \(m(t)\) and \(s(t)\) and want to solve for \(K(t)\) and \(s_{lc}(t)\) then things look non-linear:

\[m(t) = K(t) s_{lc}(t) - K(t)s(t)\]

But Ton was writing it like:

\[m(t) = A(t) - K(t)s(t)\]

If we have:

  • \(n\) time samples in a cycle
  • \(m\) cycles
  • \(p\) sensors
  • \(q\) controls

Then for one cycle:

  • \(K\): \(q \times p\)
  • \(s\): \(p \times 1\)
  • \(s_{lc}\): \(p \times 1\)
  • \(m\): \(q x 1\)

\(A\) is then shape \(q \times 1\) so we could solve for the entries of \(A\) and not for \(s_{lc}\) explicitly. Then at each time step in a cycle we have \(q + qp\) unknowns giving \(nq(1 + p)\) unknowns for a cycle and thus need that many equations. Each cycle gives us \(nq\) equations so we need at least \(1 + p\) cycles to solve for the entries of \(A\) and \(K\).

comments powered by Disqus