xkonni / nes

SS2015

ACTION

canbus running in 4 beaglebones:

INSTRUCTIONS

dependencies

apt-get install i2c-tools libi2c-dev libprotobuf-dev protobuf-compiler

code

• clone this repository

  git clone https://github.com/xkonni/NES.git
  

• initialize gitmodules

  git submodule init
  

• update gitmodules

  git submodule update
  

• change to build directory

  cd controller
  

• build BBBIOlib

  cd src/lib/BBBIOlib
  make
  cd -
  

• if using can

  export CAN=1
  

• run cmake

  cmake .
  

• run make

  make
  

TODO

controller

• optional: read motorstatus

nes's Issues

Bus System Choice

Considered

• CAN
• SERCOS
• EtherCat

CAN

• Easy to implement and debug
• Messages have priorities
• Unknown delay until a message is transmitted
• Low speed
• Needs transceiver chips
• The bus is non-trivial to build

Sercos

• Bus with hard RT properties
• Inherent cycles for setting/getting data from slaves
• Very short delay between cycles possible
• Harder to configure
• No viable master implementation found
• There is only a basic API with no HW support

EtherCat

• Properties like Sercos
• Master: http://www.etherlab.org/en/ethercat/index.php
• Works with or without (slower) RT_PREEMPT patch for Linux
  • It should be manageable to get RT_PREEMPT working
• The master control process can be implemented using a C API

Proposal

• Implement a quick-and-dirty CAN bus so sensors and actuators can be steered
• When CAN works on a basic level try to set up basic EtherCat master/slave communication
  • Let the master talk to a proprietary slave
  • When the master works, try to set up a slave on a BeagleBone Black
• Implement the EtherCat control process

TODO: Decide on a deadline for basic EtherCat operations. It it's not working by then, improve the CAN bus