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nepfaff / robot_payload_id

Identifying object inertial properties using a robot arm
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Try symbolic version that declares symbolic variables for the lumped parameters that the inverse dynamics are linear in #9

Closed nepfaff closed 9 months ago

nepfaff commented 9 months ago

We have problems with declaring symbolic variables for Drake's base parameters of CoM and unit inertia as the inverse dynamics are not linear in these. Hence, we need to use DecomposeLumpedParameters instead of DecomposeLinearExpression and cannot solve the SDP with respect to these parameters. The goal of this issue is doing it similarly to the autodiff version where we declare variables for the lumped parameters h and I and then obtain Drake's base parameters from them before passing them to the plant.

nepfaff commented 9 months ago

This doesn't work as the engine is not able to simplify the expressions that come from doing this. See here for the bug report: https://github.com/RobotLocomotion/drake/issues/20666