lcmt_iiwa_status.lcm

package drake;

struct lcmt_iiwa_status {
  // The timestamp in microseconds.
  int64_t utime;

  int32_t num_joints;

  // From FRI documentation: "The currently measured joint positions of the
  // robot in radians."
  double joint_position_measured[num_joints];

  // The FRI driver does not provide velocity; we estimate it in our driver via
  // a low-pass filter.  Units are radians / sec.
  double joint_velocity_estimated[num_joints];

  // From FRI documentation: "The last commanded joint positions of the robot in
  // radians."
  double joint_position_commanded[num_joints];

  // From FRI documentation:
  // "The joint positions commanded by the interpolator in radians. When
  // commanding a motion overlay in your robot application, this method will
  // give access to the joint positions currently commanded by the motion
  // interpolator.  This method will return NULL during monitoring mode."
  //
  // The Kuka motion interpolated code is a black-box to us, so we typically do
  // not try to model/simulate this signal.
  double joint_position_ipo[num_joints];

  // From FRI documentation: "The currently measured joint torques of the robot
  // in Nm."
  //
  // This appears to be the raw measurement of the torque sensors, which is
  // attempting to track joint_torque_commanded.
  double joint_torque_measured[num_joints];

  // From FRI documentation: "The last commanded joint torques of the robot in
  // Nm."
  //
  // This appears to be most similar to the torque input to multibody plant.
  double joint_torque_commanded[num_joints];

  // From FRI documentation: "The currently measured external joint torques of
  // the robot in Nm.  The external torques corresponds to the measured torques
  // when removing the torques induced by the robot itself."
  //
  // This appears to be the contact forces (in joint coordinates) as well as any
  // residuals from modeling errors (as computed by the onboard Kuka inverse
  // dynamics model, which is a black-box to us). Recall that the inertia of
  // the tool is included (potentially very approximately) in the onboard Kuka
  // model, so long as a tool is defined in the active Sunrise project. You can
  // use the Kuka pendant to teach the tool inertia.
  double joint_torque_external[num_joints];
}