基于ROS的机械臂运动控制

Overview -------- This branch (indigo-devel) is intended for ROS Indigo and above, and uses the Catkin buildsystem. It may also be compatible with ROS Hydro. This ROS stack includes an Arduino library (called ROSArduinoBridge) and a collection of ROS packages for controlling an Arduino-based robot using standard ROS messages and services. The stack does **not** depend on ROS Serial. Features of the stack include: * Direct support for Ping sonar and Sharp infrared (GP2D12) sensors * Can also read data from generic analog and digital sensors * Can control digital outputs (e.g. turn a switch or LED on and off) * Support for PWM servos * Configurable base controller if using the required hardware The stack includes a base controller for a differential drive robot that accepts ROS Twist messages and publishes odometry data back to the PC. The base controller requires the use of a motor controller and encoders for reading odometry data. The current version of the stack provides support for the following base controller hardware: * Pololu VNH5019 dual motor controller shield (http://www.pololu.com/catalog/product/2502) or Pololu MC33926 dual motor shield (http://www.pololu.com/catalog/product/2503). * Robogaia Mega Encoder shield (http://www.robogaia.com/two-axis-encoder-counter-mega-shield-version-2.html) or on-board wheel encoder counters. **NOTE:** The Robogaia Mega Encoder shield can only be used with an Arduino Mega. The on-board wheel encoder counters are currently only supported by Arduino Uno. * The library can be easily extended to include support for other motor controllers and encoder hardware or libraries. Official ROS Documentation -------------------------- A standard ROS-style version of this documentation can be found on the ROS wiki at: http://www.ros.org/wiki/ros_arduino_bridge System Requirements ------------------- **Python Serial:** To install the python-serial package under Ubuntu, use the command: $ sudo apt-get install python-serial On non-Ubuntu systems, use either: $ sudo pip install --upgrade pyserial or $ sudo easy_install -U pyserial **Arduino IDE 1.6.6 or Higher:** Note that the preprocessing of conditional #include statements is broken in earlier versions of the Arduino IDE. To ensure that the ROS Arduino Bridge firmware compiles correctly, be sure to install version 1.6.6 or higher of the Arduino IDE. You can download the IDE from https://www.arduino.cc/en/Main/Software. **Hardware:** The firmware should work with any Arduino-compatible controller for reading sensors and controlling PWM servos. However, to use the base controller, you will need a supported motor controller and encoder hardware as described above. If you do not have this hardware, you can still try the package for reading sensors and controlling servos. See the NOTES section at the end of this document for instructions on how to do this. To use the base controller you must also install the appropriate libraries for your motor controller and encoders. For the Pololu VNH5019 Dual Motor Shield, the library can be found at: https://github.com/pololu/Dual-VNH5019-Motor-Shield For the Pololu MC33926 Dual Motor Shield, the library can be found at: https://github.com/pololu/dual-mc33926-motor-shield The Robogaia Mega Encoder library can be found at: http://www.robogaia.com/uploads/6/8/0/9/6809982/__megaencodercounter-1.3.tar.gz These libraries should be installed in your standard Arduino sketchbook/libraries directory. Finally, it is assumed you are using version 1.0 or greater of the Arduino IDE. Preparing your Serial Port under Linux -------------------------------------- Your Arduino will likely connect to your Linux computer as port /dev/ttyACM# or /dev/ttyUSB# where # is a number like 0, 1, 2, etc., depending on how many other devices are connected. The easiest way to make the determination is to unplug all other USB devices, plug in your Arduino, then run the command: $ ls /dev/ttyACM* or $ ls /dev/ttyUSB* Hopefully, one of these two commands will return the result you're looking for (e.g. /dev/ttyACM0) and the other will return the error "No such file or directory". Next you need to make sure you have read/write access to the port. Assuming your Arduino is connected on /dev/ttyACM0, run the command: $ ls -l /dev/ttyACM0 and you should see an output similar to the following: crw-rw---- 1 root dialout 166, 0 2013-02-24 08:31 /dev/ttyACM0 Note that only root and the "dialout" group have read/write access. Therefore, you need to be a member of the dialout group. You only have to do this once and it should then work for all USB devices you plug in later on. To add yourself to the dialout group, run the command: $ sudo usermod -a -G dialout your_user_name where your\_user\_name is your Linux login name. You will likely have to log out of your X-window session then log in again, or simply reboot your machine if you want to be sure. When you log back in again, try the command: $ groups and you should see a list of groups you belong to including dialout. Installation of the ros\_arduino\_bridge Stack ---------------------------------------------- $ cd ~/catkin_workspace/src $ git clone https://github.com/hbrobotics/ros_arduino_bridge.git $ cd ~/catkin_workspace $ catkin_make The provided Arduino library is called ROSArduinoBridge and is located in the ros\_arduino\_firmware package. This sketch is specific to the hardware requirements above but it can also be used with other Arduino-type boards (e.g. Uno) by turning off the base controller as described in the NOTES section at the end of this document. To install the ROSArduinoBridge library, follow these steps: $ cd SKETCHBOOK_PATH where SKETCHBOOK_PATH is the path to your Arduino sketchbook directory. $ cp -rp `rospack find ros_arduino_firmware`/src/libraries/ROSArduinoBridge ROSArduinoBridge This last command copies the ROSArduinoBridge sketch files into your sketchbook folder. The next section describes how to configure, compile and upload this sketch. Loading the ROSArduinoBridge Sketch ----------------------------------- * If you are using the base controller, make sure you have already installed the appropriate motor controller and encoder libraries into your Arduino sketchbook/librariesfolder. * Launch the Arduino 1.0 IDE and load the ROSArduinoBridge sketch. You should be able to find it by going to: File->Sketchbook->ROSArduinoBridge NOTE: If you don't have the required base controller hardware but still want to try the code, see the notes at the end of the file. Choose one of the supported motor controllers by uncommenting its #define statement and commenting out any others. By default, the Pololu VNH5019 driver is chosen. Choose a supported encoder library by by uncommenting its #define statement and commenting out any others. At the moment, only the Robogaia Mega Encoder shield is supported and it is chosen by default. If you want to control PWM servos attached to your controller, look for the line: <pre> #define USE_SERVOS </pre> and make sure it is not commented out like this: <pre> //#define USE_SERVOS </pre> You must then edit the include file servos.h and change the N_SERVOS parameter as well as the pin numbers for the servos you have attached. * Compile and upload the sketch to your Arduino. Firmware Commands ----------------- The ROSArduinoLibrary accepts single-letter commands over the serial port for polling sensors, controlling servos, driving the robot, and reading encoders. These commands can be sent to the Arduino over any serial interface, including the Serial Monitor in the Arduino IDE. **NOTE:** Before trying these commands, set the Serial Monitor baudrate to 57600 and the line terminator to "Carriage return" or "Both NL & CR" using the two pulldown menus on the lower right of the Serial Monitor window. The list of commands can be found