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how to activate iCub gyroscopes

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Nuno Guedelha edited this page Feb 21, 2018 · 2 revisions

Overview of gyroscopes connection logic on iCub v2.5 ETHERNET based robots, respective configuration in the URDF and robots-configuration files.

Gyroscopes logic connections

Logic and harness schematics

The iCub v2.5 ETHERNET based logic and harness schematics depict the boards embedding these sensors, how these boards are inter-connected and how they are connected to the main board LAN:

Most of the gyroscopes are embedded in EMS boards, except for the ones embedded in the MTB boards 1B7 and 2B7 mounted on the hand palms (refer to the distributed inertial sensing documentation in iCub wikis).

We describe below the main EMS, 2FOC, MC4 and Mainboard logic connections:

Main EMS boards connections for the arms

Gyroscopes on the MTB boards

The activation of the gyroscopes on the MTB boards is trivial and doesn't need additional configuration files or work, so we won't address this here.

Gyroscopes on the EMS boards

  • All EMS boards are daisy chain connected to the mainboard LAN. Each of them has an accelerometer LIS331DLH and a gyroscope L3G4200D. Only the gyroscope in each EMS board is handled by the firmware (embObjInertials device implementation).

  • Left arm: The EMS1 (EB1) is connected to the pair of 2FOC boards controlling the arm motors, but the EMS1 is mounted on the back of the torso as shown in the diagram above. The same way, the EMS2 is connected to the MTB boards mounted on the left arm, but that EMS board is actually mounted on the torso as well. So the gyroscopes embedded in the boards EMS1,2,3,4 will be exposed on Yarp as sensors on the torso.

  • Waist and legs: EMS5 (EB5) is mounted on the waist between the 2 hips. There are 3 boards on the left leg: EMS6 and EMS10 are mounted on the upper leg, EMS7 on the lower leg. A set of daisy-chained MTB boards (10B1 to 10B13) is plugged onto EMS10, for the skin support. An embObjInertials device along with an analogServer network wrapper handle the accelerometers on those MTB boards and the gyroscope on the EMS10.

URDF and sensor names

The gyroscopes sensor names in the URDF generated from the CAD are correctly named and have the correct parent link after their placement on the real robot. For instance, the gyroscope embedded on the board EB9, mounted on the right lower leg, is named r_lower_leg_ems_acc_eb9 and has for parent link r_lower_leg.

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