Week 7

In the beginning of this week has been set a goal: finish the hardware. This means finish all the connections, install the Arduinos, the back LED status panel and fix everything up.

The first task was to project a way to fix the used eletronic. It was drawn, in SolidWorks, a board that could fit in the rack mount. Some holes and space was left to fix the Arduinos and to pass to cables. The used material was polycarbonate (similar to acrylic). This design can be watched further in this post.

After that, the goal was to make the board to put the Arduino Micro to receive the encoder signals. As you can see in the picture below, screw connectors were used to make the connections.

placa_ArdMicro

Another detail is the existing socket, witch will be used to place capacitors to filter the signals from the encoders.

After mount the Arduino Micro, the rest was assembled and tested in the mean time:

Montagem_arduinos_vista1

Arduinos and relay module installed with connections.

Montagem_arduinos_vista2

In this picture it is possible to observer the pan/tilt unit installed.

The next step was to connect the LED status panel to the main circuit, and make the emergency button disable the DC drives power and the ON/OFF disable the DC power supplies (DC/DC converters).

montageem_traseira.jpg

After the assembly the following items were successfully tested:

  • Status LED’s : 5, 12 and 48V;
  • Emergency button;
  • ON/OFF button;
  • Read encoder data and transmit it via I2C;
  • Data transmission via Ethernet to ROS;
  • Actuate motors (the motors can be actuated but not as desired)

Despite that, a major problems persists, the motors are not rotating both ways. There is a problem with the PWM signals to the DC drive that could not be solved yet.

 

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