Artist residency: Êtres et Numérique

#Day #4

The previous evening, we had a problem with Poppy. We were not able anymore to communicate with the leg motors:

    512             except ValueError:
    513                 msg = 'could not parse received data {}'.format(map(ord, data))
--> 514                 raise DxlCommunicationError(self, msg, instruction_packet)
    515 
    516             logger.debug('Receiving %s', status_packet,

DxlCommunicationError: could not parse received data [0] after sending DxlPingPacket(id=0)

One of our USB2AX dongle was gone. After some investigation, I have found a damaged cable between r_hip_x and r_hip_z motors. The 12V and Data lines were unsheathed and I think there was a short circuit. I contacted Nicolas Saugnier (creator of these dongles), he told me that USB2AX v3.1 were protected to this kind of short-circuit but not the v3.0. The dead USB2AX was indeed a v3.0.

I went back to Inria for advanced repairs. It appeared that this short circuit had also ruined 2 motors: l_hip_x and r_knee_y…

During my trip to inria, 3 people ( @Steve, @omangin and Clement) decided to join the residency to work on the curiosity driven exploration algorithm I explained in my previous post. So a parallel scientific hackaton emerged from the first test days:

For my case, I continued to work with the dancer, we spent the day working on the design of a choreography involving Poppy on the floor:

However even after repairs, I had still erratical troubles to communicate with the robot:

  File "c:\users\poppy\documents\pypot\pypot\dynamixel\io.py", line 494, in __re
al_send
    nbytes = self._serial.write(data)
  File "C:\Python27\lib\site-packages\serial\serialwin32.py", line 270, in write

    raise writeTimeoutError
SerialTimeoutException: Write timeout

I think, it is a problem with one of the motor which has been damaged by the short circuit but not enough to be broken. So it is really difficult to find and replace it. In the evening, the problem was more and more present so I decided to exchange working parts between our 2 Poppy:

And we finally managed to finish our work on the choreography at 3am …

###Note
Today we lost a lot of time and energy caused (supposed) by a short circuit. Also, it ruined at least 2 motors and probably damaged few more …
For the Poppy I version, we will have to think about this problem and try to protect, as much as possible, the wires.