Chico joint calibration

We explain here how to calibrate Chico's joint encoders.

General calibration procedure

• Power-cycle (i.e., switch off and on) the board controlling the joint that you want to calibrate.

• With the emergency/fault button pressed down, launch iCubInterface --config $ICUB_ROOT/app/iCubLisboa01/conf/icubRaw.ini

• Launch robotMotorGui

• Manually align the joints to a desired zero position and write down the values provided by robotMotorGui

• Open $ICUB_ROOT/app/iCubLisboa01/conf/iCub_Calibration_Lisboa_001.xls

• Go to the desired joint section; edit the yellow fields with the robotMotorGui values that you have previously noted down; observe the resulting red values.

• Edit $ICUB_ROOT/app/iCubLisboa01/conf/icub_<limb>_safe.ini and write the new "red" values that you have just read in the XLS. The rows to edit are typically: Zeros, Min, Max, Encoders, Calibration1, Calibration3.

• Update $ICUB_ROOT/app/iCubLisboa01/conf/icub_<limb>.ini as well.

• With the emergency/fault button must be pressed down, launch iCubInterface --config $ICUB_ROOT/app/iCubLisboa01/conf/icubSafe.ini

• Verify these things:
  • that the zero position makes physical sense, i.e., it is really close to the desired zero;
  • manually move the joints a bit around the zero position, check that the values provided by robotMotorGui are changing continuously, without glitches or jumps

• Calibration is now complete. You are ready to run iCubInterface with the motors enabled (emergency button up).

Example: shoulder calibration

• With canLoader20, flash the old firmware version 1.51 to board number 2 (example for right shoulder: pcan, net 2, board 2).

• For the icubRaw.ini phase, follow the instructions of the general calibration procedure above, and proceed in this order:
  • Manually place the 3 shoulder joints to a position that is consistent to the desired values (0, 0, any). This corresponds to the arm being vertical and perpendicular to the floor. Write down the first two encoder values provided by robotMotorGui; let's call them "first value" and "second value".
  • Next, manually put the shoulder to position (first value - 30, second value + 30, 0), which means that the first two values are given by the formula, while the third joint must be in a position that corresponds to the desired zero. Take note of the "third value" provided now by robotMotorGui.

• Update the XLS file as per general procedure.

• With canLoader20, flash back to the new firmware version 1.53.