Extracting Joint Gravity Term in FRI of KUKA LBR IIWA

  • Hi,

    I would like to get the information of the joint gravity vector (the G(q) term of the rigid body equation of motion) that KUKA internally computed and applied.

    I see that in the old FRI, the gravity (and also mass matrix and Jacobian) are provided, as you can see here: https://github.com/CentroEPiag…_hw/include/fri/friComm.h

    The FRI that we currently use are using Protobuf, with a file named friLBRState.h (version 1.7, written in 2014-2015), and it has interfaces such as getMeasuredTorque(), getCommandedTorque(), getExternalTorque(), but I could NOT find anything related to gravity (nor mass matrix).

    Is there anyway I can get information of this gravity term? Thanks!

    Best Regards,


  • AD
  • massula

    Approved the thread.
  • Hello,

    if you're using an old 1.7 version, I guess you could still find it as below,

    As far as I know, these functions are not provided and supported by KUKA since 2016.

    ModelParameterRequestService MPRS = new ModelParameterRequestService(lbr);
    IModelParameters MP = MPRS.requestModelData();
    Matrix mass = MP.getMassMatrix();
    Matrix jacob = MP.getJacobianMatrix();

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