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iCub 3 - Stator/Rotor auto-calibration

This page shows how to run the autocalibration procedure of the rotor/stator alignement on iCub 3.

Prepare the XML files

In order to get the values to put in the XML files, we need to modify the file enabling the autocalibration.

The files are located in robots-configuration/robots-icebox/iCubGenova09/hardware/mechanicals.

Accordingly to the joint you have to calibrate, select the corresponding file and set AutoCalibration param to 1 and RotorIndexOffset to 0:

 <group name="2FOC">
        <param name="AutoCalibration">       1             1       </param>
        <param name="Verbose">               0             0       </param>
        <param name="HasHallSensor">         0             0       </param>
        <param name="HasTempSensor">         0             0       </param>
        <param name="HasRotorEncoder">       1             1       </param>
        <param name="HasRotorEncoderIndex">  1             1       </param>
        <param name="HasSpeedEncoder">       0             0       </param>
        <param name="RotorIndexOffset">      0             0       </param>
        <param name="MotorPoles">            12            8       </param>
   </group>

Run yarprobotinterface

In order to get the value to be written in the XML file above, yarprobotinterface needs to be launched.

Info

In order to get less messages from the yarprobotinterface log, better off enabling the calibration only for the joint that needs to be calibrated. To do that in the corresponding calibration file, edit the CALIB_ORDER param to contain only the number of the joint you need: 

            <param name="CALIB_ORDER"> (0) (1) (2) (3) (4) (5) </param>

Retrieve the offset from the log messages

Once yarprobotinterface is running, check the log messages and look for a DEBUG message regarding the joint being under calibration as below:

[DEBUG]  from BOARD 10.0.1.10 (right_leg-eb10-j0_1), src CAN1, adr 1, time 92s 891m 994u: (code 0x04000002, par16 0x8119 par64 0xffcc0042ffff0079) -> DEBUG: tag02 + .

Looking at par64, the rightmost 4 digits are the offset: 0x0079 = 121 degrees; this is the value to save in the file (see next steps).

The first DEBUG messages have the rightmost 4 digits equal to the default value 0xffff until the offset is not found.

Warning

The 8 leftmost digits (in the example 0xffcc0042) must be not 0!
Otherwise the calibration is failed/not completed.

Note

The joint number is determined by its 2FOC CAN address, considering that adr can be in [1-4]:

Example 1 (right_leg-eb10-j0_1), src CAN1, adr 1 -> adr 1 is the first joint defined in right_leg-eb10-j0_1, so joint 0

Example 2 (right_leg-eb11-j2_3), src CAN1, adr 2 -> adr 2 is the second joint defined in right_leg-eb11-j2_3, so joint 3

Put the values in the XML files

Once the value of the autocalibration is retrieved, just put it in the corresponding XML file.

For the value retrieved above we need to modify the joint 0 column of file and set AutoCalibration back to 0:

The column order in the file follows the joint order in the file-name; in the case of right_leg-eb10-j0_1-mec.xml, the first column is for joint 0 and the second one is for joint 1.

<group name="2FOC">
        <param name="AutoCalibration">       0             0          </param>
        <param name="Verbose">               0             0          </param>
        <param name="HasHallSensor">         0             0          </param>
        <param name="HasTempSensor">         0             0          </param>
        <param name="HasRotorEncoder">       1             1          </param>
        <param name="HasRotorEncoderIndex">  1             1          </param>
        <param name="HasSpeedEncoder">       0             0          </param>
        <param name="RotorIndexOffset">      121           358        </param>
        <param name="MotorPoles">            12            8          </param>
   </group>

Warning

In order to have the modification working, reboot the control boards before running yarprobotinterface again.